Efeito de extratos vegetais de Hamamelis virginiana, Persea americana, Cynara scolymus L e Stryphnodendron barbatiman Msobre a expressão fenotípica dos fatores de virulência em biofilmes de Candida albicans / Effect of Hamamelis virginiana, Persea americana, Cynara scolymus L and Stryphnodendron barbatiman M plant extracts on the phenotypic expression of virulence factors in biofilms of the Candida albicans

Objetivo: Analisar a expressão fenotípica de fatores de virulência em biofilmes de Candida albicans frente a extratos glicólicos de plantas. Material e Métodos: Os biofilmes de Candida albicans (ATCC 18804) obtidos a partir de incubação de 48 horas foram expostos por 5 minutos e 24 horas a diferentes concentrações de extratos glicólicos de Hamamelis virginiana e Persea americana, Cynara scolymus L e Stryphnodendron barbatiman M, a fim de verificar a ação antifúngica da proteinase, fosfolipase e hemolisina. Resultados: Todos os extratos foram eficazes na redução do biofilme. Em contato por 5 minutos. os extratos reduziram 50% do biofilme. Após 24 horas. o extrato de Persea americana apresentou o biofilme em 90%, seguido de Cynara scolymus, que o interrompeu em 85%. Houve mudança na intensidade da proteinase após 5 minutos e 24 horas, com uma atividade enzimática média de 0,69 em comparação com o controle de 0,49. Cynara scolymus foi o extrato com maior concentração média de 100 mg/ml; a intensidade da fosfolipase foi alterada com Stryphnodendron barbatiman sendo mais efetivo em 24 horas em relação ao controle (p< 0,0001). A secreção de hemolisina foi modificada por Hamamelis virginiana (12,5 mg/ml) após 5 minutos de exposição e em 24 horas. todos os extratos foram capazes de causar alterações na secreção. Conclusão: Os extratos testados apresentam potencial antifúngico em biofilmes de Candida albicans, implicando em redução significativa dos fatores de virulência. Assim, estes podem ser indicados como uma ferramenta terapêutica alternativa para reduzir a morbidade dessas infecções, já que em ambos os tempos de exposição investigados, eles foram capazes de reduzir a secreção enzimática do fungo (AU)

Objective: Analyze the phenotypic expression of virulence factors in Candida albicans biofilms against plant glycolicextracts. Material and Methods: The biofilms of Candida albicans (ATCC 18804) obtained from incubation for 48 hours were exposed for 5 minutes and 24 hours to different concentrations of glycolic extracts of Hamamelis virginiana and Persea americana, Cynara scolymus L and Stryphnodendron barbatiman M, in order to verify the antifungal activity of the proteinase, phospholipase and hemolysin. Results: All extracts were effective in reducing biofilm. In contact for 5 minutes. the extracts reduced 50% of the biofilm. After 24 hours, the Persea americanaextract showed the biofilm at 90%, followed by Cynara scolymus, which interrupted it at 85%, There was a change in proteinase intensity after 5 minutes and 24 hours. with an average enzymatic activity of 0.69 compared to the control of 0.49. Cynara scolymus was the extract with the highest mean concentration of 100 mg/ml; the phospholipase intensity was changed with Stryphnodendron barbatiman being more effective in 24 hours compared to the control (p< 0.0001). The hemolysin secretion was modified by Hamamelis virginiana (12.5 mg/ml) after 5 minutes of exposure, and in 24 hours. all extracts were capable to cause changes in secretion. Conclusion: The tested extracts have antifungal potential in Candida albicans biofilms, implying a significant reduction in virulence factors. Thus, these can be indicated as an alternative therapeutic tool to reduce the morbidity of these infections, as in both investigated exposure times. they were able to reduce theenzymatic secretion of the fungus (AU)

Actividad de fosfolipasas y proteasas en aislamientos de especies de Candida colonizadoras y causantes de vulvovaginitis en mujeres gestantes / Phospholipase and proteinase activities of isolatesof colonizing Candida spp. causing vulvovaginitis in pregnant women

Introducción. Las proteasas y las fosfolipasas son factores de virulencia de Candida spp. que cumplen un papel importante en la invasión de los tejidos. Entre los factores relacionados con el huésped, se encuentran algunos asociados con las características ambientales y otros con la colonización. Objetivo. Determinar la actividad de fosfolipasas y proteasas en aislamientos de especies colonizadoras y patógenas de Candida spp., aisladas de mujeres gestantes de Cartagena de Indias. Materiales y métodos. Se determinó la actividad de fosfolipasas y proteasas en 56 aislamientos mediante degradación del sustrato y cálculo del coeficiente de actividad enzimática. Se compararon las actividades de fosfolipasas y proteasas, entre los aislamientos colonizadores y los patógenos. Resultados. La actividad de la fosfolipasa fue "muy alta" (< 0,69) en 34 aislamientos e, igualmente, la de la proteasa en 14. No hubo diferencias significativas al comparar las actividades de las fosfolipasas y de las de las proteasas, entre los aislamientos colonizadores y los patógenos. Conclusiones. La actividad de las fosfolipasas predominó como factor de virulencia en los aislamientos estudiados. No obstante, no se encontró una diferencia significativa entre los grupos de aislamientos colonizadores y los patógenos, en cuanto a las actividades de fosfolipasas y proteasas.

Introduction. Proteases and phospholipases are virulence factors of Candida spp. that play an important role in tissue invasion. Among the factors related to the host some are associated with environmental characteristics and others with Candida colonization. Objectives. To determine phospholipase and protease activities in colonizing and pathogenic strains, isolated from pregnant women in Cartagena de Indias. Materials and methods. Phospholipase and protease activity was determined in 56 isolates, evaluating substrate degradation and calculating the enzyme activity coefficient. Phospholipase and protease activities were compared between colonizing and pathogenic strains. Results. "Very high" (<0.69) phospholipase and protease activity was found in 34 and 14 isolates, respectively. There was no significant difference when comparing phospholipase and protease activities between colonizing and pathogenic isolates. Conclusions. Phospholipase activity predominated as a virulence factor in the studied strains, but no significant difference was found between colonizing and pathogenic strains for phospholipase and protease activities.

Genotipos de virulencia de Helicobacter pylori y su asociación con lesiones precursoras de malignidad gástrica y parámetros histológicos en pacientes colombianos / Helicobacter pylori virulence genotypes and their relationship with precursor lesions of gastric malignancy and histological parameters in infected patients in Colombia

Se determinó la presencia de los genotipos de virulencia de Helicobacter pylori y su asociación con las lesiones precursoras de malignidad gástrica y parámetros histológicos en pacientes con síntomas de dispepsia del suroccidente de Colombia. Se realizó reacción en cadena de polimerasa (PCR) para la caracterización genética de vacA, cagA, babA2 y sabA. Se empleó la prueba de chi cuadrado o Fischer para evaluar la asociación de cada genotipo sobre el desenlace clínico. En los pacientes con lesiones precursoras de malignidad gástrica se encontró que el 86,3% presentaron el genotipo vacA s1/m1, el 68,1% cagA+ y los genotipos babA2+ y sabA+ con el 68,8% y 55,8%, respectivamente. También, se demostró la asociación entre los genotipos de virulencia y el grado severo de infiltración de células polimorfonucleares. Además, se encontró una asociación entre la combinación de los genes vacA/cagA, vacA/sabA y babA2/sabA. Este estudio proporciona evidencia acerca de la asociación de los genotipos de virulencia del H. pylori y la inflamación gástrica en pacientes infectados.

The aim of this research was to determine the presence of Helicobacter pylori virulence genotypes and their association with precursor lesions of gastric malignancy and histological parameters in patients with dyspepsia symptoms in southwestern Colombia. Polymerase chain reaction (PCR) was used for the genetic characterization of vacA, cagA, babA2 and sabA. The chi-square or Fischer test were used to evaluate the association between each genotype and the clinical outcome. We found that 86.3% of the patients with precursor lesions of gastric malignancy presented the vacA s1/m1 genotype, 68.1% had the cagA+ genotype and 68.8% and 55.8% had the babA2+ and sabA+ genotypes, respectively. Our results show association between virulence genotypes and severe degree of polymorphonuclear cell infiltration. In addition, we found an association between the combination of vacA/cagA, vacA/sabA and babA2/sabA genes. This study provides evidence about the association of H. pylori virulence genotypes and gastric inflammation in infected patients.

Detection and expression of SapS, a class C nonspecific acid phosphatase with O-phospho-L- tyrosine-phosphatase activity, in Staphylococcus aureus isolates from patients with chronic osteomyelitis / Detección y expresión de SapS, una fosfatasa ácida no específica de clase C con actividad de fosfatasa O-fosfotirosina, en aislamientos de Staphylococcus aureus de pacientes con osteomielitis crónica

Introduction. The identity of Staphylococcus aureus virulence factors involved in chronic osteomyelitis remains unresolved. SapS is a class C non-specific acid phosphatase and a well-known virulence factor that has been identified in S. aureus strain 154 but in protein extracts from rotting vegetables. Objective. To identify the SapS gene and characterize the activity of SapS from S. aureus strains: 12 isolates from bone infected samples of patients treated for chronic osteomyelitis and 49 from a database with in silico analysis of complete bacterial genomes. Materials and methods. The SapS gene was isolated and sequenced from 12 S. aureus clinical isolates and two reference strains; 49 S. aureus strains and 11 coagulase-negative staphylococci were tested using in silico PCR. Culture media semi-purified protein extracts from the clinical strains were assayed for phosphatase activity with p-nitro-phenyl- phosphate, O-phospho-L-tyrosine, O-phospho-L-serine, and OphosphoL-threonine in conjunction with various phosphatase inhibitors. Results. SapS was detected in the clinical and in-silico S. aureus strains, but not in the in silico coagulase-negative staphylococci strains. Sec-type I lipoprotein-type N-terminal signal peptide sequences; secreted proteins, and aspartate bipartite catalytic domains coding sequences were found in the SapS nucleotide and amino acid sequence analysis. SapS dephosphorylated with p-nitro-phenyl-phosphate and ophosphoLtyrosine were selectively resistant to tartrate and fluoride, but sensitive to vanadate and molybdate. Conclusion. SapS gene was found in the genome of the clinical isolates and the in silico S. aureus strains. SapS shares biochemical similarities with known virulent bacterial, such as protein tyrosine phosphatases, suggesting it may be a virulence factor in chronic osteomyelitis.

Introducción. Se desconoce la identidad de los factores de virulencia de Staphylococcus aureus implicados en la osteomielitis crónica. Sin embargo, SapS, una fosfatasa ácida no específica de clase C, es un factor de virulencia reconocido y ya fue identificada en la cepa 154 de S. aureus, pero en extractos proteicos de vegetales podridos. Objetivo. Detectar el gen SapS y caracterizar la actividad de la fosfatasa SapS en cepas de S. aureus aisladas de pacientes con osteomielitis crónica y en las reportadas en una base de datos de análisis in silico de genomas bacterianos completos. Materiales y métodos. Se aisló y secuenció el gen SapS en los 12 aislamientos clínicos de S. aureus y en dos cepas de referencia; estas secuencias se analizaron junto con las secuencias de las cepas reportadas en la base de datos de genomas bacterianos: 49 cepas de S. aureus y 11 cepas de estafilococos negativos para coagulasa. Se evalúo la actividad de la fosfatasa SapS, presente en los extractos de los sobrenadantes de los cultivos de las cepas clínicas, mediante la hidrólisis de fosfato p-nitrofenil, O-fosfo-L- tirosina, O-fosfo-L serina y O-fosfo-L treonina junto con varios inhibidores de fosfatasas. Resultados. Se detectó el gen SapS en el genoma de las cepas clínicas y en las 49 cepas de S. aureus analizadas in silico, pero no en las 11 cepas de estafilococos negativos para coagulasa. La secuenciación de SapS reveló un péptido señal presente en el extremo N-terminal de proteínas extracelulares y los dominios bipartitos de aspartato (DDDD) en su sitio catalítico. SapS hidroliza selectivamente el fosfato p-nitrofenil y la O-fosfo-L-tirosina, pero es sensible a vanadato y molibdato. Conclusión. Se encontró SapS en el genoma de S. aureus de las cepas clínicas y de las cepas de simulación computacional. La SapS con actividad específica para la hidrólisis de la O-fosfo-L-tirosina comparte similitudes bioquímicas con las fosfatasas-tirosina bacterianas, por lo que puede formar parte de la red de factores de virulencia de la osteomielitis crónica.

Candida albicans the main opportunistic pathogenic fungus in humans / Candida albicans el principal hongo patógeno oportunista en humanos

Abstract Candida albicans is a commensal of the mammalian microbiome and the primarypathogenic fungus of humans. It becomes a severe health problem in immunocompromisedpatients and can cause a wide variety of mucosal and systemic infections. The interactionbetween C. albicans and host cells is characterized by the expression of virulence factors suchas adhesins and invasins, the secretion of hydrolytic enzymes, a transition from yeast to fil-amentous hyphae form, and the ability to form biofilms; these features collectively result in cell adhesion, invasion, and damage. This review describes complex commensal interactions of C. albicans with host cells and the cellular events that it triggers in a pathogenic environment. We also review the host immune response induced by C. albicans antigens and the mechanisms developed by this fungus to avoid the action of antifungal agents.

Resumen Candida albicans es un comensal del microbioma de mamíferos y el principal hongopatógeno de humanos. En pacientes inmunocomprometidos se convierte en un grave problemade salud por causar una amplia variedad de infecciones en mucosas y sistémicas. La interacciónentre C. albicans y las células del huésped lleva a la expresión de factores de virulencia, comoadhesinas e invasinas, a la secreción de enzimas hidrolíticas y a la transición de levadura a hifa filamentosa, capaz de para formar biopelículas, lo que genera adherencia, invasión y dano celular. En esta revisión describimos la compleja interacción comensal de C. albicans con la célula huésped y los eventos celulares que ejecuta en un ambiente patogénico. También se revisa la respuesta inmunitaria del huésped inducida por antígenos de C. albicans y los mecanismos desarrollados por este hongo para evitar la acción de agentes antifúngicos.

Helicobacter pylori infection: A balance between bacteria and host / Helicobacter pylori: un balance entre bacterias y huésped

Abstract In Argentina, despite the important studies conducted on the prevalence of infection and the antibiotic resistance of Helicobacter pylori, there are no reports simultaneously analyzing a profile of virulence factors of the bacterium and polymorphisms in cytokine genes in patients with different alterations in the gastric mucosa (including intestinal metaplasia, IM). Our aim was to evaluate H. pylori genotypes in 132 adult patients with chronic gastritis presenting three different histological findings (inactive chronic gastritis, active chronic gastritis IM( and active chronic gastritis IM+) along with SNP-174 G>C in the IL-6 gene. cagA, vacA and babA2 genes were analyzed by multiplex PCR. The -174 G>C SNP IL-6 gene was analyzed by PCR-RFLP. Patients with active chronic gastritis IM+ showed the highest proportion of the cagA(+)/IL-6GG, cagA(+)/vacAm1s1/IL-6GG and cagA(+)/vacAm1s1/babA2(+)/IL-6GG combinations (p<0.05). There was 4-5 times greater probability of finding patients presenting the GG genotype for SNP-174 G>C IL-6, which in turn were infected with the most virulent H. pylori genotypes -cagA(+), cagA(+)/vacAm1s1 and cagA(+)/vacAm1s1/babA2- in the ACGIM+ group in comparison to the ICG group. Our results provide regional data to the idea that the transition towards severe alterations in the gastric mucosa would be the result of a balance between specific factors of H. pylori and inherent host factors. This fact can be useful to identify patients at greater risk and to select those individuals requiring appropriate eradication treatment to prevent progression to gastric cancer.

Resumen En Argentina, a pesar de los importantes estudios realizados sobre la prevalencia de infección y la resistencia a antibióticos de Helicobacter pylori, no existen reportes que analicen simultáneamente un perfil de factores de virulencia de la bacteria y polimorfismos en genes de citoquinas en pacientes con diferentes alteraciones en la mucosa gástrica (incluida la metaplasia intestinal [MI]). Nuestro objetivo fue evaluar genotipos de H. pylori en 132 pacientes adultos con gastritis crónica, con tres diferentes hallazgos histológicos (gastritis crónica inactiva [GCI], gastritis crónica activa [MI(] y gastritis crónica activa [MI+]), junto con el SNP-174 G>C en el gen de IL- 6. Los genes cagA, vacA y babA2 se analizaron mediante PCR multiplex. El SNP-174 G>C IL-6 se analizó mediante PCR-RFLP. Los pacientes con gastritis crónica activa MI+ mostraron la mayor proporción de combinaciones cagA(+)/IL-6GG, cagA(+)/vacAm1s1/IL-6GG y cagA(+)/vacAm1s1/babA2(+)/IL-6GG (p<0,05). Hubo 4-5 veces mayor probabilidad de encontrar pacientes con el genotipo GG en SNP-174 G>C IL-6 y a su vez infectados con los genotipos más virulentos de H. pylori-cagA(+), cagA(+)/vacAm1s1 y cagA(+)/vacAm1s1/babA2-en el grupo gastritis crónica activa MI+ en comparación con el grupo GCI. Nuestros resultados aportan datos regionales a la idea de que la transición hacia alteraciones más graves en la mucosa gástrica resultaría de un equilibrio entre factores específicos de H. pylori y factores inherentes al huésped. Esto puede ser útil para identificar pacientes con mayor riesgo y seleccionar aquellos individuos que requieran un apropiado tratamiento de erradicación para prevenir la progresión al cáncer gástrico.

Virulence associated characteristics and drug resistance of Klebsiella pneumoniae isolated from patients living in Zhongjiang county of Sichuan province / 中国基层医药

Objective:To investigate the distribution characteristics of virulence-related phenotypes/genotype, capsular serotype, drug resistance phenotypes, and sequence typing (ST) of Klebsiella pneumoniae in patients living in Zhongjiang county, improve clinical understanding, and provide evidence for the prevention and control of bacterial drug resistance and clinical rational drug use. Methods:The data of 135 strains of Klebsiella pneumoniae isolated from patients who received treatment in Zhongjiang County People's Hospital from July to December 2019 were retrospectively analyzed. Bacterial identification and drug sensitivity testing were performed using the WalkAway-40Plus automated microbiology system. Strains with a high viscosity phenotype were identified using wire drawing experiments. Hypervirulence-associated capsular serotype and virulence genes were verified by polymerase chain reaction. ST of Klebsiella pneumoniae strain was identified using multilocus sequence typing. Results:Strains with a high viscosity phenotype were identified in 50.4% of the 135 strains. 54.1%, 54.8%, and 54.1% of the strains were positive for virulence genes iucA, iroN, rmpA. The proportion of strains with capsular Serotype K1 or K2 was 11.9% and 15.6%, respectively. A total of 65 kinds of ST were identified, with ST23 and ST37 being the most common, accounting for 11.1% and 6.7%, respectively. The resistance rate of the strains to 16 kinds of antibiotics was 0.0%-25.2%, and the resistance rate to Carbapenem antibiotics, Amikacin, and Tigecycline was less than 1%. The positive rate of virulence gene of strains with a high viscosity phenotype was significantly higher than that of strains without a high viscosity phenotype ( P < 0.001), and its resistance rate to Cephalosporin was significantly lower in strains with a high viscosity phenotype than that in strains without a high viscosity phenotype ( P < 0.001). Conclusion:Klebsiella pneumoniae in Zhongjiang County is characterized by "high virulence and low drug resistance". It is necessary to continuously monitor the changes in the virulence and drug resistance of Klebsiella pneumoniae in Zhongjiang County, Sichuan Province, and be alert to the rapid dissemination of highly virulent strains.

Streptococcus mutans e seu metabolismo a nível molecular no contexto ecológico da doença cárie / Streptococcus mutans and its metabolism at the molecular level in the ecological context of dental caries

Objetivo: Durante décadas, o Streptococcus mutans foi con-siderado o principal agente etiológico da doença cárie. Esta revisão apresentará seu histórico e metabolismo a nível molecular. Ao entender as vias metabólicas do S.mutans envolvidas no desenvolvimento de lesões cariosas, será possível desenvolver novos métodos de modulação de biofilmes no controle da doença cárie e elucidar a neces-sidade de continuar pesquisando essa bactéria. Revisão de literatura: Embora o S. mutans não constitua uma pro-porção significativa na colonização da microbiota bucal da dentição hígida, essa proporção aumenta quando há acidificação contínua do biofilme, associada ao excesso de carboidratos na dieta do hospedeiro. Isso ocorre devido a um conjunto de fatores de virulência, tais como, adesão, formação de biofilme, acidogenicidade, aciduricidade, atividades de proteases, produção de mutacinas e vias de transdução de sinal. Cada uma dessas propriedades, coordenadamente, alteram a ecologia do biofilme dental. Discussão: Ainda é relevante entender o metabolismo do S. mutans como microrganismo modelo em lesões cariosas devido a seus inúmeros fatores de virulência. Porém, no contexto da doença cárie como uma disbiose, estratégias terapêuticas antimicrobianas, mais especificamente anti-S.mutans, voltadas para a eliminação do microrganismo, po-dem não ser a chave do controle da doença cárie, enquanto a modulação do microbioma poderá se tornar o futuro das clínicas odontológicas. Conclusão: Biofilmes associados a doença cárie compreendem um ecossistema diverso, sugerindo uma etiologia polimicrobiana, porém, estudos futuros que visem à prospecção, ao desenvolvimento e à inter-relação do S. mutans com outros microrganismos e com o hospedeiro humano ainda são justificados a fim de desvendar a transição 'homeostase-disbiose'.

Aim: For decades, the Streptococcus mutans was consi-dered the main agent of caries. This review will show its history and metabolism at the molecular level. By understanding its metabolic pathways involved in the development of carious lesions, it can be possible to develop new methods of modulating biofilms in the control of caries, as well as to elucidate the need to continue researching this bacterium. Literature review: Although S. mutans does not constitute a significant proportion in the colonization of the oral microbiota of the sound dentition, its proportion increases when there is continuous acidification of the biofilm, asso-ciated with excess carbohydrates in the host diet. This is due to a set of virulence factors, such as adhesion, biofilm formation, acidogenicity, aciduricity, proteases activity, mutacins production and signal transduction pathways. Each of these properties coordinately alters the ecology of the dental biofilm. Discussion: It is still relevant to understand the metabolism of S. mutans as a model microorganism in carious lesions due to its numerous virulence factors. However, in the context of caries as a dysbiosis, antimicrobial therapeutic strategies, more specifically anti-S.mutans, aiming to eliminate the microorganism, may not be the key to caries control, and the microbiome modulation may become the future of dental clinics. Conclusion: Biofilms associated with caries disease comprise a diverse ecosystem, suggesting a polymicrobial etiolo-gy, however, future studies aimed at the prospection, development and interrelationship of S. mutans with other microorganisms and with the human host are still justified in order to unravel the 'homeos-tasis-dysbiosis' transition.

Helicobacter pylori: novedades, genes de virulencia y resistencia a los antibióticos en Colombia / Helicobacter pylori: novelties, virulence genes and antibiotic resistance in Colombia / Helicobacter pylori: novidades, genes de virulência e resistência aos antibióticos na Colômbia

Helicobacter pylori es un carcinógeno tipo I resistente a múltiples antibióticos y con alta prioridad en salud pública. La infección por este microorganismo está influenciada por una interacción compleja entre la genética del huésped, el entorno y múltiples factores de virulencia de la cepa infectante. Afecta al 50 % de la población mundial, provocando afecciones gastroduodenales graves, la mayoría de forma asintomática. El 20 % de los individuos con H. pylori pueden desarrollar a través del tiempo lesiones gástricas preneoplásicas y el 2 % de ellos un cáncer gástrico. Las manifestaciones clínicas gastrointestinales y extragastrointestinales están asociadas a su virulencia y a la respuesta del sistema inmunológico con la liberación de citosinas proinflamatorias, tales como TNF-alfa, IL-6, IL-10 e IL-8, causantes de inflamación aguda y crónica. Múltiples factores de virulencia han sido estudiados como el gen A asociado a la citotoxina (CagA) y la citotoxina vacuolante (VacA), los cuales juegan un rol importante en la aparición del cáncer gástrico. Dada la resistencia cada vez mayor a los antibióticos utilizados, las líneas de estudio en el futuro inmediato deben estar encaminadas en establecer la utilidad de los nuevos antibióticos y la determinación de profagos colombianos en todo el país. Esta revisión tiene como objetivo hacer una puesta al día sobre las características del H. pylori, los mecanismos patogénicos, genes de virulencia, su asociación con el mayor riesgo de cáncer gástrico, farmacorresistencia microbiana y su erradicación.

Helicobacter pylori is recognized as a class I carcinogen resistant to multiple antibiotics and with high priority in public health. The infection caused by this microorganism is influenced by a complex interaction between host genetics, environment, and multiple virulence factors of the infecting strain. It affects 50% of the world population, causing severe gastroduodenal conditions, most of them asymptomatic. Through time, 20% of individuals with H. pylori may develop preneoplastic gastric lesions and 2% of them develop gastric cancer. The gastrointestinal and extra-gastrointestinal clinical manifestations are associated with its virulence and the response of the immune system with the release of pro-inflammatory cytokines, such as TNF-alpha, IL-6, IL-10 and IL-8, which cause acute and chronic inflammation. Multiple virulence factors have been studied, such as cytotoxin-associated gene A (CagA) and vacuolating cytotoxin A (VacA), which play an important role in the development of gastric cancer. Due to the increasing antibiotics resistance, the research in the immediate future should be aimed at establishing the usefulness of the new antibiotics and the determination of Colombian prophages throughout the country. This paper aims to update the characteristics of H. pylori, its pathogenic mechanisms, virulence genes, its association with the increased risk of gastric cancer, microbial drug resistance, and eradication.

Helicobacter pylorié um carcinógeno tipo I resistente a múltiplos antibióticos e com alta prioridade na saúde pública. A infecção por este microrganismo está influenciada por uma interação complexa entre a genética do hospede, o entorno e múltiplos fatores de virulência da cepa infectante. Afeta a 50% da população mundial, provocando afeções gastroduodenais graves, a maioria de forma assintomática. 20% dos indivíduos com H. pylori podem desenvolver através do tempo lesões gástricas pré-neoplásicas e 2% deles um câncer gástrico. As manifestações clínicas gastrointestinais e extragastrointestinais estão associadas à sua virulência e à resposta do sistema imunológico com a liberação de citocinas pró-inflamatórias, tais como TNF-alfa, IL-6, IL-10 e IL-8, causantes de inflamação aguda e crónica. Múltiplos fatores de virulência hão sido estudados como o gene. A associado à citotoxina (CagA) e a citotoxina vacuolante (VacA), os quais jogam um papel importante no aparecimento do câncer gástrico. Dada a resistência cada vez maior aos antibióticos utilizados, as linhas de estudo no futuro imediato devem estar encaminhadas em estabelecer a utilidade dos novos antibióticos e a determinaçãode profagos colombianos em todo o país. Esta revisão tem como objetivo fazer uma atualização sobre as características do H. pylori, os mecanismos patogénicos, genes de virulência, sua associação com o maior risco de câncer gástrico, farmacorresistência microbiana e sua erradicação.

ß-lactamasas de espectro extendido y factores de virulencia en Escherichia coli uropatógenas en asilos de ancianos en Lima, Perú / ß-lactamases and virulence factors in uropathogenic Escherichia coli in nursing homes in Lima, Peru

RESUMEN Los asilos de ancianos son instituciones con una alta prevalencia de infecciones del tracto urinario ocasionado por Escherichia coli productoras de ß-lactamasas de espectro extendido (BLEE), con diversos factores de virulencia. El objetivo del estudio fue determinar la frecuencia del gen bla CTX-M y de ocho genes de virulencia en 35 E. coli uropatógenas productoras de BLEE provenientes de seis asilos en Perú, durante el 2018. El 57,1% (20/35) de las E. coli fueron portadores del gen bla CTX-M. Además, se obtuvo una frecuencia del 46% (15/35) y 37% (13/35) de hly-alfa y cnf-1, respectivamente; elevada presencia de los genes iucC (63%, 22/35), aer (94%, 33/35) y chuA (94%, 33/34) y una frecuencia del 46% (16/35) y del 91% (32/34) de los genes pap GII y nanA, respectivamente. Existe predominancia en la distribución del gen bla CTX-M, además de una alta frecuencia de exotoxinas que le confieren una ventaja competitiva para diseminarse hacia el torrente sanguíneo.

ABSTRACT Nursing homes are institutions with high prevalence of urinary tract infections caused by ESBL-producing E. coli with several virulence factors. The aim of this study was to determine the frequency of the bla CTX-M gene and eight virulence genes in 35 ESBL-producing uropathogenic E. coli from six nursing homes in Peru during 2018. Of the E. coli samples, 57.1% (20/35) were carriers of the bla CTX-M gene. Furthermore, we obtained frequencies of 46% (15/35) and 37% (13/35) for hly-alpha and cnf-1, respectively; we also found high presence of the iucC (63%, 22/35), aer (94%, 33/35) and chuA genes (94%, 33/34) as well as a frequency of 46% (16/35) and 91% (32/34) for the pap GII and nanA genes, respectively. The bla CTX-M gene is predominant and a high frequency of exotoxins gives it a competitive advantage for spreading into the bloodstream.

Stress response and virulence factors in bacterial pathogens relevant for Chilean aquaculture: current status and outlook of our knowledge

The study of the stress responses in bacteria has given us a wealth of information regarding the mechanisms employed by these bacteria in aggressive or even non-optimal living conditions. This information has been applied by several researchers to identify molecular targets related to pathogeny, virulence, and survival, among others, and to design new prophylactic or therapeutic strategies against them. In this study, our knowledge of these mechanisms has been summarized with emphasis on some aquatic pathogenic bacteria of relevance to the health and productive aspects of Chilean salmon farming (Piscirickettsia salmonis, Tenacibaculum spp., Renibacterium salmoninarum, and Yersinia ruckeri). This study will aid further investigations aimed at shedding more light on possible lines of action for these pathogens in the coming years.

Progress in pathogenesis of perinatal group B streptococcal infection / 中华围产医学杂志

Group B Streptococcus (GBS) is a major cause of severe perinatal infection, stillbirth, premature delivery, and neonatal infectious diseases. Ascending infection after vaginal colonization is the main route of prenatal GBS transmission. The pathogenic mechanism of GBS from asymptomatic colonization to invasive infection mainly relates to virulence factors, the regulation of two-component systems and immune escape. This paper reviews progress in pathogenic mechanism of perinatal GBS infection in recent years, aiming to provide a theoretical basis for the development of vaccines and new treatment approaches against GBS.

Drug resistance and virulence characteristics of of Staphylococcus aureus isolated from skin sites of suppurative infections in Inner Mongolia / 中华皮肤科杂志

Objective:To analyze drug resistance, virulence and molecular epidemiological characteristics of Staphylococcus aureus ( S. aureus) isolated from skin sites of suppurative infections, and to provide an experimental basis for clinical anti-infective therapies. Methods:Swab samples from suppurative skin lesions and nasal secretions were collected from inpatients in Department of Dermatology, the Affiliated Hospital of Inner Mongolia Medical University from May 2020 to December 2020, and subjected to bacterial isolation and culture. Suspected S. aureus colonies were identified by matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Drug sensitivity test was conducted by using the broth microdilution method. Virulence genes of S. aureus were amplified by PCR, and real-time fluorescence-based quantitative PCR was performed to determine the relative expression of 4 virulence genes including tsst-1, pvl, hla and clfA in S. aureus strains from different sources. S. aureus strains were genotyped by multilocus sequence typing. Drug resistance rates and detection rates of virulence genes were compared by using chi-square test or Fisher′s exact test, and measurement data among groups were compared by using t test or Mann-Whitney U test. Results:A total of 85 strains of S. aureus were isolated from 210 inpatients, including 54 isolates from skin sites of suppurative infections (case group) and 31 isolates from the nasal cavity (control group) . Drug sensitivity test showed that 14 strains of methicillin-resistant S. aureus (MRSA) were identified among 85 strains of S. aureus. The resistance rate to penicillin was the highest (90.59%, 77/85) in the 85 S. aureus strains; the resistance rates to clindamycin and erythromycin were 60.00% (51/85) and 61.18% (52/85) respectively; no strains showed resistance to rifampicin, vancomycin or linezolid. PCR showed that the detection rate of the pvl gene was 33.33% (18/54) in the case group, which was significantly higher than that in the control group (12.90%, 4/31; χ2= 4.28, P= 0.038) . Real-time fluorescence-based quantitative PCR showed that the relative expression level of the clfA gene was significantly higher in the control group (3.87[2.30, 5.94]) than in the case group (1.63[0.95, 2.62], P= 0.007) . A total of 17 ST types were identified among the 85 strains of S. aureus, and the dominant types were ST398-methicillin-susceptible S. aureus (20/71) and ST22-MRSA (9/14) . The detection rate of the virulence gene pvl was significantly higher in the ST22-MRSA strain (14/14) than in the non-ST22 MRSA strains (0, P < 0.001) . Conclusions:S. aureus strains isolated from the skin sites of suppurative infections were highly resistant to penicillin, clindamycin and erythromycin, so these antibiotics should not be used as the first-choice empiric treatment. The occurrence of cutaneous S. aureus infections may be associated with the virulence gene pvl, and the nasal colonization of S. aureus may be associated with the clfA gene.

Research progress in infection-associated virulence factors of Staphylococcus aureus / 中华临床感染病杂志

Staphylococcus aureus is an important pathogen of human infectious diseases, which can cause skin and soft tissue infections, endocarditis, necrotizing pneumonia, myelitis and other serious infectious diseases. With the use of antibiotics, Staphylococcus aureus is evolving to develop drug resistance; at the same time it produces a variety of virulence factors to attack the host. This article will review the recent advances of Staphylococcus aureus virulence factors associated with the three stages of infection and introduce the detection methods of virulence factors briefly.

Research progress on pathogenicity and mechanism of important virulence factors of Moraxella catarrhalis / 中华检验医学杂志

Moraxella catarrhalis ( Mca) is a kind of gram-negative diplococcus which can exist in the respiratory tract of the human. It could be a non-symptom diplococcus on the health people. Otitis media occurs when the Mca reaches the middle ear along the eustachian tube. Sometimes the patients could suffer from the acute exacerbation of chronic obstructive pulmonary disease or pneumonia due to lung lesions caused by Mca. Little is known about the pathogenesis of the Mca, which leads to an incomplete understanding of its pathogenicity. This review aims to clarify the relationships between the Mca and the related diseases and the mechanism of the significant virulence factors. We hope to raise awareness of Mca and also provide some ideas for clinical diagnosis of relevant diseases it caused.

Molecular characteristics and virulence genes of Staphylococcus aureus in bloodstream infection from children during 2016-2021 / 中华检验医学杂志

Objectives:To study the molecular characteristics, virulence gene and resistance profiles of Staphylococcus aureus ( S. aureus, SA) isolates from bloodstream infections (BSI), so as to further understand the molecular characteristics of S. aureus in pediatric patients. Methods:A total of 53 S. aureus strains in bloodstream infections from Shanghai Children′s Hospital between 2016 and 2021 were collected. Antimicrobial susceptibility test were adopted by instrumental and disk diffusion method. Thirty-two kinds of virulence genes were detected by PCR and underwent multi-locus sequence typing (MLST), Staphylococcus protein A (spa) typing and staphylococcal chromosome cassette (staphylococcal cassette chromosome mec, SCCmec) typing characterizing methicillin-resistant Staphylococcus aureus (MRSA). Statistical analysis was performed using χ 2 test or Fisher exact test. Results:MRSA isolates accounted for 50.94% of the total(27/53), with ST398-t034-SCCmecV (6/53, 11.32%) and ST59-t437-SCCmecIV (4/53, 7.55%) as the most common MRSA clones. Methicillin-sensitive Staphylococcus aureus (MSSA) isolates occupied 49.06% (26/53), among which typing ST22-t309 (3/53, 5.66%) and ST7-t091/t1685 (2/53, 3.77% each) were prevalent. Of the 53 strains, all carried ≥6 virulence genes, 33 strains (62.26%) carried ≥10 virulence genes, including 18 strains of MSSA (69.23%) and 15 strains of MRSA (55.56%). The carriage rate of pvl gene in MSSA was higher than that of MRSA isolates (12/26, 33.33% vs. 6/27, 22.22%), and sasX was only detected in MRSA isolates (4/53, 7.55%). The resistant rates of BSI-SA isolates to penicillin, erythromycin and clindamycin were 98.11%, 49.06% and 41.51%, respectively. MRSA were more resistant to clinical antimicrobial agents than MSSA. Conclusions:MRSA strains cover a high proportion in S. aureus bloodstream infection of children, with ST398-t034 and ST59-t437 being the most common clones. The virulence gene carrying rate for BSI-SA was high with a greater pvl gene carrying rate in MSSA isolates while sasX was only detected in MRSA isolates. More clinical attention should be paid to the high resistance status and virulence genes characteristics of BSI-SA.

Caracterização molecular de Staphylococcus aureus isolados de queijos artesanais da Serra da Canastra / Molecular characterization of Staphylococcus aureus isolated from artisanal cheeses from Serra da Canastra

O queijo Minas Artesanal da Canastra é produzido na Serra da Canastra (MG), utilizando leite cru, coalho e pingo, que é uma cultura endógena natural de cada queijaria. Devido ao uso de leite cru, o produto pode veicular microrganismos causadores de doenças veiculadas por alimentos, como Staphylococcus aureus. A caracterização molecular é uma ferramenta importante para avaliar a população microbiana do alimento e direcionar a aplicação de medidas de controle na produção. Este estudo caracterizou a diversidade genética, o potencial de virulência e determinou o perfil de susceptibilidade a antimicrobianos de S. aureus isolados de queijos produzidos na Serra da Canastra. Para o estudo transversal foram analisados 248 isolados de queijos que tinham um tempo de maturação de 22 dias, provenientes de 83 propriedades. Por outro lado, no estudo longitudinal foram analisados outros 197 isolados coletados ao longo do processo de maturação, provenientes de três propriedades. Os isolados foram submetidos a testes bioquímicos para confirmação do gênero e para a confirmação da espécie de S. aureus, foi identificado o gene nuc por meio da técnica de PCR. Além disso, foi pesquisado o gene mecA para a detecção de S. aureus Resistente a Meticilina (MRSA). Após os testes de confirmação, 144 isolados do estudo transversal e 159 do estudo longitudinal foram positivos para o gene nuc, específico para S. aureus. Posteriormente, o perfil clonal foi determinado por Eletroforese de Campo Pulsado (PFGE) utilizando a enzima SmaI e tipagem do locus agr por PCR multiplex. A análise por PFGE foi realizada no programa BioNumerics. A técnica PCR foi realizada para identificar a presença de genes que codificam a produção de hemolisinas, toxina TSST-1, enterotoxinas SEs (SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI, SEJ, SEO, SEM), formação de biofilme e Componentes Microbianos de Superfície que Reconhecem a Matriz de Moléculas Adesivas (MSCRAMMs). Os isolados foram submetidos ao teste de susceptibilidade a antimicrobianos por disco de difusão. Por último, a formação de biofilme em microplaca de 96 poços, em caldo TSB a 37°C, foi verificada pela metodologia de Cristal Violeta. O gene mecA foi detectado em 1,9% dos 445 isolados. A tipagem agrrevelou que 83 (27,4%) dos isolados são do tipo agr-I, 95 (31,4%) agr-II e 43 (14,2%) agr-III, sendo que não foram detectados isolados classificados como agr-IV. A tipagem por PFGE revelou um total de 54 perfis. Assim, um isolado representativo de cada perfil foi utilizado nos demais testes que mostraram a presença dos genótipos spa mais frequentes t127 e t605 (20,58%); t002 (14,70%), seguidos pelos tipos t267 (8,82%); t1234 e t693 (5,8%) e t021, t177, t306, t321, t359, t442, t521, t693 e t5493 (2,9%). Além disso, encontramos a presença dos genes do grupo SEs, sea 1 (1,8%), seh 11 (20,3%), sei 10 (18,5%), sej 7 (12,9%), seg e seo 14 (25,9%), sem 8 (14,8%), e os genes seb, sec, sed, see e tst não foram detectados. Para os genes das hemolisinas, hla foi positivo em todos os isolados e hlb foi positivo em 53 (98,1%) isolados. Os genes positivos para MSCRAMMS foram fnbA, fnbB 18 (33,3%), clfA, clfB e eno 53 (98,1%), fib 44 (81,4%), bbp 4 (7,4%), cna 17 (31,4%) e ebps 10 (18,5%). Por último, os genes de formação de biofilme icaA e icaD estiveram presentes em 38 (70,3%) e 25 (46,2%) dos isolados, respectivamente. Na avaliação de susceptibilidade a antibióticos dos 54 isolados escolhidos, 25 (46,3%) apresentaram maior resistência a penicilina e 13 (24,0%) a tetraciclina. Em menor porcentagem (1,8%), 1 isolado cada foi resistente a eritromicina, cefoxitina, clindamicina, gentamicina, cotrimazol, azitromicina e trimetropim. Além disso, 8 isolados (14,8%) apresentaram resistência intermediaria a tetraciclina, 3 (5,5%) a gentamicina e 1 (1,8%) a tobramicina. No teste para a determinação da formação de biofilme por cristal violeta, 13,7%, foram classificados em isolados não formadores, 60,8% em fracamente formadores, 25,5% moderadamente formadores e nenhum como fortemente formador. A alta diversidade de cepas de S. aureus observada neste estudo mostrou que existem vários tipos de linhagens circulando na região da Canastra. A caracterização revelou uma elevada frequência de genes de virulência e que mais estudos são necessários para avaliar o potencial de produção de enterotoxinas nos queijos artesanais. A melhora dos procedimentos de higienização durante todas as etapas de produção pode ser uma solução para a redução dos níveis de contaminação por S. aureus

Canastra Minas Artesanal cheese is produced in Serra da Canastra (MG), using raw milk, rennet and a natural endogenous culture called pingo. Due to the use of raw milk, the product can carry microorganisms that cause foodborne diseases, such as Staphylococcus aureus. Molecular characterization is an important tool to assess the microbial population of food and guide the application of control measures in production. This study characterized the genetic diversity, virulence potential and determined the antimicrobial susceptibility profile of S. aureus isolated from cheeses produced in Serra da Canastra. A total of 248 isolates from 22 days ripened cheeses were obtained from 83 properties (cross sectional study). Another 197 isolates were collected during maturation (longitudinal study), in three properties. The isolates were submitted to biochemical tests to confirm the genus and to confirm the S. aureus species, the nuc gene was identified by PCR. In addition, the detection of mecA gene was performed for the detection of Methicillin Resistant S. aureus (MRSA). After confirmation tests, 144 isolates from the cross-sectional study and 159 from the longitudinal study were positive for the nuc gene, specific for S. aureus. Subsequently, the clonal profile of the isolates was determined by Pulsed Field Gel Electrophoresis (PFGE) using the SmaI enzyme and typing of the agr locus by multiplex PCR. PFGE analysis was performed using the BioNumerics program. PCR was performed to identify the presence of genes encoding the production of hemolysins, TSST-1 toxin, enterotoxins SEs (SEA, SEB, SEC, SED, SEE, SEG, SEH, SEI, SEJ, SEO, SEM), biofilm formation and microbial surface components recognizing adhesive matrix molecules (MSCRAMMs). The isolates were submitted to the antimicrobial susceptibility test by disc diffusion. Finally, biofilm formation in a 96-well microplate in TSB broth at 37°C was verified by the Cristal Violeta method. The mecA gene was detected in 1.9% of the 445 isolates. Agr typing revealed that 83 (27.4%) of the isolates are agr-I, 95 (31.4%) agr-II and 43 (14.2%) agr-III, and no isolate was classified as agr-IV. PFGE typing revealed a total of 54 profiles. Thus, a representative isolate of each profile was used in the other tests that showed the presence of the most frequent spagenotypes t127, t605 (20.58%); t002 (14.70%), followed by types t267 (8.82%); t1234, t693 (5.8%) e t021, t177, t306, t321, t359, t442, t521, t693 and t5493 (2.9%). In addition, we found the presence of the genes of the SEs group: sea 1 (1.8%), seh 11 (20.3%), sei 10 (18.5%), sej 7 (12.9%), seg and seo 14 (25.9%), sem 8 (14.8%), while seb, sec, sed, see and tst genes were not detected. For hemolysin genes, hla was positive in all isolates and hlb was positive in 53 (98.1%) isolates. The positive genes for MSCRAMMS were: fnbA, fnbB 18 (33.3%), clfA, clfB e eno 53 (98.1%), fib 44 (81.4%), bbp 4 (7.4%), cna 17 (31.4%) and ebps 10 (18.5%). Finally, the biofilm formation genes icaA and icaD were present in 38 (70.3%) and 25 (46.2%) of the isolates, respectively. In the evaluation of antibiotic susceptibility of the 54 isolates, 25 (46.3%) showed greater resistance to penicillin and 13 (24.0%) to tetracycline. In a lower percentage (1.8%), 1 isolate each was resistant to erythromycin, cefoxitin, clindamycin, gentamicin, contrimazole, azithromycin and trimethoprim. In addition, 8 isolates (14.8%) showed intermediate resistance to tetracycline, 3 (5.5%) to gentamicin and 1 (1.8%) to tobramycin. In the test for the determination of biofilm formation by crystal violet, 13.7% were classified as non-forming isolates, 60.8% as weakly forming, 25.5% moderately forming and none as strongly forming. The high diversity of S. aureus strains observed in this study showed that there are several types of strains circulating in the Canastra region. The characterization revealed a high frequency of virulence genes and that further studies are needed to assess the potential for enterotoxin production in artisanal cheeses. The improvement of hygiene procedures during all stages of production can be a solution for reducing the levels of contamination by S. aureus

Expressão e localização celular da diguanilato ciclase DgcP em Pseudomonas aeruginosa / Expression and cell localization of the diguanylate cyclase DgcP in Pseudomonas aeruginosa

A bactéria Gram-negativa Pseudomonas aeruginosa é um patógeno oportunista frequentemente associado a vítimas de queimaduras graves ou indivíduos com fibrose cística, sendo os isolados resistentes a carbepenêmicos dessa espécie considerados pela OMS como uma das maiores ameaças ao controle de infecções. O estabelecimento da infecção por esse patógeno é dependente de uma série de fatores de virulência, entre eles o pilus tipo IV (T4P), que possui papel importante na adesão a superfícies e motilidade do tipo twitching, essenciais para a colonização do hospedeiro. Uma das moléculas importantes na diferenciação entre as formas séssil e planctônica de P. aeruginosa é o segundo mensageiro bis-(3,5)-di-guanosina monofosfato cíclico (c-di-GMP), cuja síntese é feita enzimaticamente por diguanilato ciclases (DGCs). DgcP é uma DGC localizada nos polos da célula, que tem sua atividade de síntese de c-di-GMP aumentada na presença da proteína FimV, essencial para a montagem do T4P em P. aeruginosa. Neste trabalho, ensaios de microscopia de fluorescência, organização e expressão gênica foram realizados com o objetivo de aumentar a compreensão sobre o papel de DgcP em relação a sua expressão e aos fatores que regulam o T4P de P. aeruginosa. A proteína DgcP em fusão com mNeonGreen no C-terminal, expressa a partir do locus cromossômico, se localiza de maneira predominantemente bipolar tanto na linhagem selvagem quanto nos mutantes ΔpilA, ΔpilR e ΔchpA, evidenciando que seu padrão de localização não depende dos sistemas de regulação Pil-Chp e PilS-PilR. Ensaios de RT-PCRmostraram que dgcP se encontra em operon com PA14_72430 e dsbA1, indicando um papel celular conjunto entre esses genes, até o momento, desconhecido. Por fim, ensaios de qRT-PCR revelaram que os níveis de mRNA de dgcP são invariáveis nas linhagens WT, ΔpilA, ΔpilR, ΔchpA e ΔfimV, cultivadas em meio líquido ou meio sólido. Os resultados aqui mostrados, combinados com trabalhos prévios do nosso e de outros grupos, sugerem que DgcP é uma diguanilato ciclase responsável por geração constante de c-di-GMP nos polos da célula, possivelmente, atuando na sinalização local dependente do dinucleotídeo cíclico, cuja localização e atividade não são dependentes dos sistemas de regulação que atuam sobre o T4P

The Gram-negative bacterium Pseudomonas aeruginosa is an opportunistic pathogen often associated with severe burn victims or individuals with cystic fibrosis, which carbapenem-resistant isolates were classified by th World Health Organization classified one of the greatest threats to infection control. The establishment of infection by this pathogen is dependent on a series of virulence factors, including the type IV pilus (T4P), which plays an important role in adhesion to surfaces and twitching motility, essential features for host colonization. Bis-(3',5')-cyclic dimeric guanosine monophosphate (c-di-GMP) is a second messenger that involved in processes of biofilm formation, motility, and virulence. The diguanylate cyclase DgcP synthetizes cdi-GMP and it is located at the cell poles, and its activity depends on the scaffold protein FimV, essential for T4P assembly in P. aeruginosa. By increasing c-di-GMP levels, DgcP decreases flagellum-dependent motility and increases biofilm formation. In this work, fluorescence microscopy, gene organization and expression assays were performed to understand the whether DgcP localization and expression are under the control of T4P regulatory proteins. Fluorescence microscopy analysis showed that DgcP localizes predominantly at both cell poles in ΔpilA, ΔpilR, and ΔchpA mutants, showing that its localization pattern does not depend on the Pil-Chp and PilS-PilR systems. Furthermore, RT-PCR assays showed that dgcP is found in an operon with PA14_72430 and dsbA1, indicating an unknown putative related cellular role for these genes. Finally, qRT-PCR assays indicated that DgcP expression is invariant in ΔpilA, ΔpilR, ΔchpA, and ΔfimV mutants, either in liquid or solid medium. The results shownhere, combined with previous work by ours and other groups, suggest that DgcP is a diguanylate cyclase responsible for constant generation of c-di-GMP at the cell poles, possibly acting in local signaling dependent on the cyclic dinucleotide, but that is not under the control of the known T4P regulatory systems

Clarithromycin-resistant H. pylori primary strains and virulence genotypes in the Northeastern region of Brazil

ABSTRACT The increase of H. pylori resistance to clarithromycin is a concern. This study evaluated the prevalence of H. pylori's primary resistance to clarithromycin and its association with virulence factors in adult dyspeptic patients and asymptomatic children. The gastric mucosa from patients (153 gastritis, 24 gastric cancer, 21 peptic ulcer) and gastric juice obtained by string test from 24 H. pylori and 23S rRNA positive asymptomatic children were included. The clarithromycin resistance was assessed by TaqMan RT-PCR 23S rRNA point mutations, A2142G and/or A2143G, and H. pylori virulence markers by PCR. Overall, the clarithromycin resistance was 14.4% (32/222), 14.2% in adults, and 12% in children, whereas origin, gender, and disease were not distinctive factors. The most prevalent point mutation was A2143G (62.5%). The point mutation was significantly less frequent in cagA-positive (11.4%) than in cagA-negative (23.6%) strains (p=0.03 OR = 0.4 95%CI = 0.19 - 0.91) as well as in cagE-positive (10.2%), cagE-negative (21.2%) (p=0.03 OR: 0.4 I.C:0.20-0.91). No difference was found in iceA or vacA alleles genotypes. Primary resistance to clarithromycin was lower than that reported in Southeast Brazil. The cagA and cagE positive H. pylori samples have few point mutations suggesting that individuals infected with virulent strains may be more susceptible to anti-H. pylori treatment.

HELICOBACTER PYLORI cagA VIRULENCE GENE AND SEVERE ESOGASTRODUODENAL DISEASES: IS THERE AN ASSOCIATION? / Gene de virulência cagA de Helicobacter pylori e doenças esogastroduodenais severas: existe uma associação?

ABSTRACT BACKGROUND: Helicobacter pylori colonizes approximately half of the world's human population. Its presence in the gastric mucosa is associated with an increased risk of gastric adenocarcinoma, gastric lymphoma, and peptic ulcer disease. In Brazil, the high prevalence of H. pylori infection is a serious health problem. H. pylori virulence factors are associated with an increased risk of serious gastrointestinal disorders. The cagA gene encodes a cytotoxin-A-associated antigen (CagA) that is involved in bacterial pathogenicity. H. pylori strains carrying the cag pathogenicity island (cag-PAI) are significantly associated with severe clinical outcomes and histopathological changes. OBJECTIVE: The present study aims to investigate the prevalence of the cagA gene among H. pylori isolates from patients with different gastric pathologies. Further, the study hopes to verify its association with clinical outcomes. In addition, phylogenetic analysis was performed on cagA-positive H. pylori strains from patients with severe and non-severe diseases. METHODS: Gastric specimens were collected through a biopsy from 117 patients with different esogastroduodenal diseases. DNA was extracted from these gastric specimens and the polymerase chain reaction was performed to amplify the gene fragments corresponding to the 16S ribosomal RNA and cagA genes using specific primers. The polymerase chain reaction products of selected samples positive for cagA were sequenced. The sequences were aligned with reference sequences from the National Center for Biotechnology Information (NCBI) (Bethesda/USA), and a phylogenetic tree was constructed. RESULTS: H. pylori was detected in 65.9% (77/117) of Brazilian patients with different gastroduodenal disorders. Overall, 80.5% (62/77) of the strains were cagA-positive. The ages of patients with cagA-positive strains (15 males and 47 females) ranged from 18 to 74 years. The lesions were categorized as non-severe and severe according to the endoscopic and histopathological reports the most prevalent non-severe esogastroduodenal lesion was gastritis 54/77 (70.12%), followed by esophagitis 12/77 (15.58%) and duodenitis 12/77 (15.58%). In contrast, the most prevalent severe lesions were atrophy 7/77 (9.09%), followed by metaplasia 3/77 (3.86%) and gastric adenocarcinoma 2/77 (2.59%). Phylogenetic analyses performed with the partial sequences of the cagA gene obtained from local strains were grouped in the same clade. No differences in phylogenetic distribution was detected between severe and non-severe diseases. CONCLUSION: The cagA gene is highly prevalent among H. pylori isolates from gastric lesions in Brazilian patients. The presence of the cagA gene was not considered a marker of the severity of esogastroduodenal lesions in the present study. This is the first study to investigate the phylogenetic population structure of H. pylori strains in a Brazilian capital, which may improve our understanding of the clinical outcome of H. pylori infection.

RESUMO CONTEXTO: Helicobacter pylori coloniza aproximadamente metade da população humana mundial. A presença do microrganismo na mucosa gástrica está associada a um risco aumentado de adenocarcinoma gástrico, linfoma gástrico e úlcera péptica. No Brasil, a alta prevalência de infecção por H. pylori é um grave problema de saúde. Os fatores de virulência de H. pylori estão associados a risco aumentado de distúrbios gastrointestinais severos. O gene cagA codifica um antígeno associado à citotoxina A (CagA) que está envolvido na patogenicidade bacteriana. As cepas de H. pylori portadoras da ilha de patogenicidade cag (cag-PAI) estão significativamente associadas a desfechos clínicos severos e alterações histopatológicas. OBJETIVO: O presente estudo tem como objetivo investigar a prevalência do gene cagA entre isolados de H. pylori de pacientes com diferentes desordens gástricas, bem como verificar sua associação com desfechos clínicos. Além disso, a análise filogenética foi realizada em cepas de H. pylori cagA-positivas de pacientes com doenças severas e não severas. MÉTODOS: Amostras gástricas foram coletadas por meio de biópsia gástrica de 117 pacientes com diferentes doenças esogastroduodenais. O DNA foi extraído das amostras e utilizado para amplificar os fragmentos gênicos correspondentes aos genes RNA ribossomal 16S e cagA, através da reação em cadeia da polimerase. Os produtos da reação em cadeia da polimerase de amostras selecionadas positivas para cagA foram sequenciados e as sequências foram alinhadas com sequências de referência do National Center for Biotechnology Information (NCBI) (Bethesda/EUA). As análises filogenéticas foram realizadas a partir do sequenciamento e construção da árvore filogenética. RESULTADOS: H. pylori foi detectado em 65,9% (77/117) dos pacientes brasileiros com diferentes distúrbios gastroduodenais. No total, 80,5% (62/77) das cepas foram cagA-positivas. As idades dos pacientes com cepas cagA-positivas (15 homens e 47 mulheres) variaram de 18 a 74 anos. As lesões foram categorizadas como não severas e severas de acordo com o laudo endoscópico e histopatológico. A lesão esogastroduodenal não severa mais prevalente foi gastrite 54/77 (70,12%), seguida de esofagite 12/77 (15,58%) e duodenite 12/77 (15,58%). Em contraste, as lesões severas mais prevalentes foram atrofia 7/77 (9,09%), seguida de metaplasia 3/77 (3,86%) e adenocarcinoma gástrico 2/77 (2,59%). As análises filogenéticas realizadas com as sequências parciais do gene cagA obtidas de cepas locais foram agrupadas no mesmo clado. Nenhuma diferença na distribuição filogenética foi detectada entre doenças severas e não severas. CONCLUSÃO: O gene cagA é altamente prevalente entre isolados de H. pylori de lesões gástricas em pacientes brasileiros. A presença do gene cagA não foi considerada um marcador de severidade das lesões esogastroduodenais no presente estudo. Este é o primeiro estudo a investigar a estrutura filogenética da população de cepas de H. pylori em uma capital brasileira. Esses resultados irão contribuir para o entendimento sobre o desfecho clínico da infecção por H. pylori.