Fixation of pfcrt chloroquine resistance alleles in Plasmodium falciparum clinical isolates collected from unrest tribal agencies of Pakistan / Fixação de alelos de resistência à cloroquina pfcrt em isolados clínicos de Plasmodium falciparum coletados de agitações de agências tribais do Paquistão

Abstract Plasmodium falciparum resistance to Chloroquine (CQ) is a significant cause of mortality and morbidity worldwide. There is a paucity of documented data on the prevalence of CQ-resistant mutant haplotypes of Pfcrt and Pfmdr1 genes from malaria-endemic war effected Federally Administered Tribal Areas of Pakistan. The objective of this study was to investigate the prevalence of P. falciparum CQ-resistance in this area. Clinical isolates were collected between May 2017 and May 2018 from North Waziristan and South Waziristan agencies of Federally Administrated Trial Area. Subsequently, Giemsa-stained blood smears were examined to detect Plasmodium falciparum. Extraction of malarial DNA was done from microscopy positive P. falciparum samples, and P. falciparum infections were confirmed by nested PCR (targeting Plasmodium small subunit ribosomal ribonucleic acid (ssrRNA) genes). All PCR confirmed P. falciparum samples were sequenced by pyrosequencing to find out mutation in Pfcrt gene at codon K76T and in pfmdr1 at codons N86Y, Y184F, N1042D, and D1246Y. Out of 121 microscopies positive P. falciparum cases, 109 samples were positive for P. falciparum by nested PCR. Pfcrt K76T mutation was found in 96% of isolates, Pfmdr1 N86Y mutation was observed in 20%, and 11% harboured Y184F mutation. All samples were wild type for Pfmdr1 codon N1042D and D1246Y. In the FATA, Pakistan, the frequency of resistant allele 76T remained high despite the removal of CQ. However, current findings of the study suggest complete fixation of P. falciparum CQ-resistant genotype in the study area.

Resumo A resistência do Plasmodium falciparum à cloroquina (CQ) é uma causa significativa de mortalidade e morbidade em todo o mundo. Há uma escassez de dados documentados sobre a prevalência de haplótipos mutantes CQ-resistentes dos genes Pfcrt e Pfmdr1 da guerra endêmica da malária em áreas tribais administradas pelo governo federal do Paquistão. O objetivo deste estudo foi investigar a prevalência de resistência a CQ de P. falciparum nesta área. Isolados clínicos foram coletados entre maio de 2017 e maio de 2018 nas agências do Waziristão do Norte e do Waziristão do Sul da Área de Ensaio Administrada Federalmente. Posteriormente, esfregaços de sangue corados com Giemsa foram examinados para detectar Plasmodium falciparum. A extração do DNA da malária foi feita a partir de amostras de P. falciparum positivas para microscopia, e as infecções por P. falciparum foram confirmadas por nested PCR (visando genes de ácido ribonucleico ribossômico de subunidade pequena de Plasmodium (ssrRNA)). Todas as amostras de P. falciparum confirmadas por PCR foram sequenciadas por pirosequenciamento para descobrir a mutação no gene Pfcrt no códon K76T e em pfmdr1 nos códons N86Y, Y184F, N1042D e D1246Y. De 121 microscopias de casos positivos de P. falciparum, 109 amostras foram positivas para P. falciparum por nested PCR. A mutação Pfcrt K76T foi encontrada em 96% dos isolados, a mutação Pfmdr1 N86Y foi observada em 20% e 11% abrigou a mutação Y184F. Todas as amostras eram do tipo selvagem para o códon N1042D e D1246Y de Pfmdr1. No FATA, Paquistão, a frequência do alelo resistente 76T permaneceu alta apesar da remoção de CQ. No entanto, as descobertas atuais do estudo sugerem a fixação completa do genótipo resistente a CQ de P. falciparum na área de estudo.

Mecanismos de expressão de resistência aos antibióticos e saúde pública / Mechanisms of expression of resistance to antibiotics and public health / Mecanismos de expresión de la resistencia a los antibióticos y salud pública

Com o avanço da medicina e o aumento do uso de antimicrobianos, a resistência microbiana vem se tornando um problema sério na saúde pública. Para que uma bactéria se torne resistente, são necessários vários fatores, entre eles, o uso indiscriminado e prolongado de antimicrobianos e as resistências intrínsecas e adquiridas. Nesse contexto, o objetivo do trabalho foi explorar os mecanismos de ação dos antimicrobianos, de resistência e a sua importância na saúde pública. Foram utilizadas para a presente pesquisa, as bases de dados Pubmed, Google acadêmico e Scielo. Segundo a Organização Mundial da Saúde define-se resistência ao antibiótico quando o mesmo não produz mais efeito. A inserção cada vez mais frequente de antimicrobianos favorece a resistência, onde provocam uma pressão seletiva sobre os microrganismos, tornando-os resistentes a diversas drogas. O uso indiscriminado de antimicrobianos é o principal fator de resistência microbiana, assim como o uso de antimicrobianos sem exame de cultura e teste de sensibilidade. Neste sentido, conclui-se que é de suma importância a atualização de protocolos que contenham os mecanismos de resistência bacteriana a fim de minimizar o uso indiscriminado de antimicrobianos, assim como capacitar os profissionais da saúde para este problema na saúde pública.

With the advance of medicine and the increase in the use of antimicrobials, microbial resistance has become a serious problem in public health. For a bacterium to become resistant, several factors are necessary, among them, the indiscriminate and prolonged use of antimicrobials and the intrinsic and acquired resistance. In this context, the objective of the work was to explore the mechanisms of action of antimicrobials, resistance and their importance in public health. Pubmed, Google academic and Scielo databases were used for this research. According to the World Health Organization, resistance to antibiotics is defined when it no longer has an effect. The increasingly frequent insertion of antimicrobials favors resistance, where they put selective pressure on microorganisms, making them resistant to various drugs. The indiscriminate use of antimicrobials is the main factor of microbial resistance, as well as the use of antimicrobials without culture examination and sensitivity test. In this sense, it is concluded that it is extremely important to update protocols that contain the mechanisms of bacterial resistance in order to minimize the indiscriminate use of antimicrobials, as well as to train health professionals for this problem in public health.

Con los avances de la medicina y el mayor uso de antimicrobianos, la resistencia microbiana se ha convertido en un grave problema de salud pública. Para que una bacteria se vuelva resistente son necesarios varios factores, entre ellos, el uso indiscriminado y prolongado de antimicrobianos y la resistencia intrínseca y adquirida. En este contexto, el objetivo de este trabajo fue explorar los mecanismos de acción de los antimicrobianos, la resistencia y su importancia en la salud pública. Para esta investigación se utilizaron las bases de datos Pubmed, Google Scholar y Scielo. Según la Organización Mundial de la Salud, la resistencia a un antibiótico se define cuando deja de producir efecto. El uso cada vez más frecuente de antimicrobianos favorece la resistencia, ya que provocan una presión selectiva sobre los microorganismos, haciéndolos resistentes a varios fármacos. El uso indiscriminado de antimicrobianos es el principal factor de resistencia microbiana, así como el uso de antimicrobianos sin pruebas de cultivo y sensibilidad. En este sentido, se concluye que es de suma importancia actualizar los protocolos que contienen los mecanismos de resistencia bacteriana para minimizar el uso indiscriminado de antimicrobianos, así como capacitar a los profesionales de la salud para este problema en la salud pública.

Resistência antimicrobiana em uroculturas de moradores das Zonas Norte e Nordeste de Porto Alegre / Antimicrobial resistance in urine cultures of residents of North and Northeast Porto Alegre / Resistencia a los antimicrobianos en urocultivos de residentes de las Zonas Norte y Noreste de Porto Alegre

Introdução: Infecção urinária é motivo comum de consulta na Atenção Primária, requerendo tratamento empírico. Para a seleção do antimicrobiano, é necessário conhecer o perfil de resistência dos uropatógenos na comunidade. Objetivo: Analisar o perfil de resistência antimicrobiana em uroculturas realizadas em pacientes da Atenção Primária à Saúde do Serviço de Saúde Comunitária do Grupo Hospitalar Conceição, de julho de 2017 a junho de 2019. Métodos: Estudo transversal, observacional e descritivo com uroculturas de pacientes ambulatoriais das Unidades de Saúde do Serviço de Saúde Comunitária do Grupo Hospitalar Conceição, nas Zonas Norte e Nordeste de Porto Alegre, de julho de 2017 a junho de 2019. Os dados das uroculturas foram fornecidos pelo laboratório do Grupo Hospitalar e analisados por meio das proporções, por sexo, micro-organismo e resistência antimicrobiana. Resultados: Encontraram-se 2.000 uroculturas positivas no período, principalmente por Escherichia coli (75,50%), Klebsiella pneumoniae (7,80%), Staphylococcus saprophyticus (4,95%), Enterococcus specie (3,35%) e Proteus mirabilis (2,85%). Entre os antibióticos orais testados, a maior resistência foi para ampicilina (48,95%), seguida por sulfametoxazol+trimetoprima (25,85%), norfloxacino (18,05%), ciprofloxacino (18,00%), amoxicilina+clavulanato (11,05%) e nitrofurantoína (8,60%). Considerando-se apenas E. coli, as resistências foram 47,75% para ampicilina, 29,74% para sulfametoxazol+trimetoprima, 19,74% para norfloxacino e ciprofloxacino, 8,08% para amoxicilina+clavulanato e 1,99% para nitrofurantoína. Conclusões: O perfil de resistência antimicrobiana nas Zonas Norte e Nordeste de Porto Alegre sugere que sejam utilizados para tratamento empírico de infecção do trato urinário nessa localidade nitrofurantoína ou amoxicilina+clavulanato.

Introduction: Urinary tract infection is a common reason for consultation in primary care, requiring empirical treatment. For the selection of the antimicrobial, it is necessary to know the resistance profile of uropathogens in the community. Objective: To analyze the profile of antimicrobial resistance in urine cultures performed on primary health care patients from the Community Health Service of Grupo Hospitalar Conceição from July 2017 to June 2019. Methods: Cross-sectional, observational and descriptive study with urine cultures of outpatients from the Health Units from the Community Health Service of Grupo Hospitalar Conceição, in North and Northeast Porto Alegre, Brazil, from July 2017 to June 2019. The data on urine cultures were provided by the Grupo Hospitalar laboratory and analyzed through proportions, by sex, microorganism, and antimicrobial resistance. Results: Two thousand positive urine cultures were found in the period, mainly for Escherichia coli (75.50%), Klebsiella pneumoniae (7.80%), Staphylococcus saprophyticus (4.95%), Enterococcus specie (3.35%) and Proteus mirabilis (2.85%). Among the oral antibiotics tested, the most frequent resistance was to ampicillin (48.95%), followed by trimethoprim+sulfamethoxazole (25.85%), norfloxacin (18.05%), ciprofloxacin (18.00%), amoxicillin-clavulanate (11.05%) and nitrofurantoin (8.60%). Considering only E. coli, resistance was 47.75% to ampicillin, 29.74% to trimethoprim+sulfamethoxazole, 19.74% to norfloxacin and ciprofloxacin, 8.08% to amoxicillin-clavulanate and 1.99% to nitrofurantoin. Conclusions: The profile of antimicrobial resistance in the North and Northeast Zones of Porto Alegre suggests that nitrofurantoin or amoxicillin-clavulanate should be used for empirical treatment of urinary tract infection in this locality.

Introducción: La infección del tracto urinario es un motivo frecuente de consulta en atención primaria, requiriendo tratamiento empírico. Para la selección del antimicrobiano, es necesario conocer el perfil de resistencia de los uropatógenos en la comunidad. Objetivo: Analizar el perfil de resistencia antimicrobiana en urocultivos realizados en pacientes de atención primaria de salud de Serviço de Saúde Comunitária de Grupo Hospitalar Conceição de julio de 2017 a junio de 2019. Métodos: Estudio transversal, observacional y descriptivo con urocultivos de pacientes ambulatorios de las Unidades de Salud de Serviço de Saúde Comunitária de Grupo Hospitalar Conceição, en las Zonas Norte y Nordeste de Porto Alegre, de julio de 2017 a junio de 2019. Los datos de urocultivos fueron proporcionados por el laboratorio de Grupo Hospitalar y analizados a través de proporciones, por sexo, microorganismos y resistencia a los antimicrobianos. Resultados: En el período se encontraron 2.000 urocultivos positivos, principalmente por Escherichia coli (75,50%), Klebsiella pneumoniae (7,80%), Staphylococcus saprophyticus (4,95%), Enterococcus especie (3,35%) y Proteus mirabilis (2,85%). Entre los antibióticos orales probados, la mayor resistencia fue para la ampicilina (48,95%), seguida de sulfametoxazol+trimetoprima (25,85%), norfloxacina (18,05%), ciprofloxacina (18,00%), amoxicilina+clavulanato (11,05%) y nitrofurantoína (8,60%). %). Considerando solo a E. coli, la resistencia fue del 47,75% para ampicilina, 29,74% para sulfametoxazol + trimetoprima, 19,74% para norfloxacina y ciprofloxacina, 8,08% para amoxicilina + clavulanato y 1,99% para nitrofurantoína. Conclusiones: El perfil de resistencia a los antimicrobianos en las regiones Norte y Nordeste de Porto Alegre sugiere que se utilizan para el tratamiento empírico de la infección del tracto urinario en esta localidad nitrofurantoína o amoxicilina+clavulanato.

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.

Praziquantel-encapsulated niosomes against Schistosoma mansoni with reduced sensitivity to praziquantel / Niosomas encapsulados en prazicuantel contra Schistosoma mansoni con sensibilidad reducida al prazicuantel

Introduction: Praziquantel (PZQ) is the only commercially available drug for schistosomiasis. The current shortage of alternative effective drugs and the lack of successful preventive measures enhance its value. The increase in the prevalence of PZQ resistance under sustained drug pressure is, therefore, an upcoming issue. Objective: To overcome the tolerance to PZQ using nanotechnology after laboratory induction of a Schistosoma mansoni isolate with reduced sensitivity to the drug during the intramolluscan phase. Materials and methods: Shedding snails were treated with PZQ doses of 200 mg/kg twice/ week followed by an interval of one week and then repeated twice in the same manner. The success of inducing reduced sensitivity was confirmed in vitro via the reduction of cercarial response to PZQ regarding their swimming activity and death percentage at different examination times. Results: Oral treatment with a single PZQ dose of 500 mg/kg in mice infected with cercariae with reduced sensitivity to PZQ revealed a non-significant reduction (35.1%) of total worm burden compared to non-treated control mice. Orally inoculated PZQ- encapsulated niosomes against S. mansoni with reduced sensitivity to PZQ successfully regained the pathogen's sensitivity to PZQ as evidenced by measuring different parameters in comparison to the non-treated infected animals with parasites with reduced sensitivity to PZQ. The mean total worm load was 1.33 ± 0.52 with a statistically significant reduction of 94.09% and complete eradication of male worms. We obtained a remarkable increase in the percentage reduction of tissue egg counts in the liver and intestine (97.68% and 98.56%, respectively) associated with a massive increase in dead eggs and the complete absence of immature stages. Conclusion: PZQ-encapsulated niosomes restored the drug sensitivity against laboratory- induced S. mansoni adult worms with reduced sensitivity to PZQ.

Introducción. El prazicuantel es el único fármaco disponible comercialmente para la esquistosomiasis. La escasez actual de medicamentos alternativos y la falta de medidas preventivas eficaces aumentan su valor. La creciente prevalencia de la resistencia al prazicuantel bajo una presión prolongada del fármaco es, por tanto, un tema emergente. Objetivos. Superar la tolerancia al prazicuantel mediante nanotecnología después de la inducción en laboratorio de un aislamiento de Schistosoma mansoni con sensibilidad reducida al fármaco durante la fase intramolusco. Materiales y métodos. Los caracoles que liberaban cercarias se trataron con prazicuantel en dosis de 200 mg/kg dos veces por semana, seguidas de un intervalo de una semana, y luego se repitieron dos veces de la misma manera. La inducción exitosa de la sensibilidad reducida se confirmó in vitro mediante la reducción de la reacción de las cercarias al prazicuantel con respecto a su actividad de natación y el porcentaje de muerte en diferentes momentos de examen. El éxito en inducir una menor sensibilidad se confirmó in vitro mediante la reducción de la reacción de las cercarias al prazicuantel. Resultados. El tratamiento oral con una dosis única de prazicuantel de 500 mg/kg en ratones infectados con cercarias con sensibilidad reducida al prazicuantel, reveló una reducción no significativa (35,1 %) de la carga total de gusanos en comparación con los ratones de control no tratados. Los niosomas encapsulados en prazicuantel inoculados por vía oral contra S. mansoni con sensibilidad reducida al prazicuantel, permitieron reestablecer con éxito la sensibilidad del patógeno al medicamento, como lo demostró la medición de diferentes parámetros en comparación con los animales infectados no tratados con parásitos con sensibilidad reducida a prazicuantel. La carga media total de gusanos fue de 1,33 ± 0,52, con una reducción estadísticamente significativa del 94,09 %, y la erradicación completa de los gusanos machos adultos. Se obtuvo un aumento notable en el porcentaje de reducción del recuento de huevos en el tejido del hígado y el intestino (97,68 % y 98,56 %, respectivamente), asociado con un aumento masivo de huevos muertos y ausencia total de estadios inmaduros. Conclusión. Los niosomas encapsulados en prazicuantel restauraron la sensibilidad al fármaco contra gusanos adultos de S. mansoni con sensibilidad reducida al prazicuantel inducida en el laboratorio.

Tuberculosis resistente a medicamentos de primera línea en pacientes del cantón Durán, Ecuador / First-line drug-resistant tuberculosis in patients from the city of Duran, Ecuador

La tuberculosis continúa siendo un problema de salud pública. Al respecto, se realizó un estudio no experimental de corte transversal, con el objetivo de caracterizar clínica y epidemiológica-mente el estado de la TB resistente a medicamentos de primera línea en la ciudad de Durán, desde enero 2015 hasta diciembre 2019. Los datos incluidos en los documentos de la matriz del programa de tuberculosis resistente. De 1111 casos nuevos de tuberculosis reportados en el cantón Durán durante el período estudiado, 45 de estos presentaron resistencia a medicamentos de primera línea. El 88,89% tuvo resistencia a rifampicina, el 33,33% de los pacientes se dispen-sarizaron en 2019. Los valores de chi cuadrado de Pearson no mostraron asociación estadística-mente significativa entre las variables investigadas (p>0,05). Entre los involucrados predominó el grupo de edades de 20 a 39 años, el sexo masculino, la tuberculosis pulmonar, infectados con VIH/sida, resistencia clasificada como primaria, los que abandonaron el seguimiento al trata-miento y la no manifestación de reacciones adversas a los medicamentos. No se observó mortali-dad entre los casos nuevos, predominando entre aquellos con recaída, el género masculino y los que tuvieron tuberculosis extrapulmonar.

Tuberculosis is a disease that continues to be a public health problem. In this regard, a non-expe-rimental cross-sectional study was carried out to characterize clinically and epidemiologically the status of TB resistant to first-line drugs in the city of Durán, from January 2015 to December 2019. The data included in the resistant tuberculosis program matrix documents. 1111 new cases of tuberculosis were reported in the Duran canton during the study period, 45 of these ones presented resistance to first-line drugs. 88.89% had rifampicin resistance, 33.33% of the patients were dispensed in 2019. Pearson's chi-square values did not show a statistically significant asso-ciation between the investigated variables (p> 0.05). Among the study population, it was predo-minated the age group between 20 and 39, male sex, pulmonary tuberculosis, infected with HIV / AIDS, resistance classified as primary, those who abandoned the follow-up to treatment and the non-manifestation of adverse drug reactions. No mortality was observed among new cases, predominantly among those ones with relapse, the male gender and those ones who had extra-pulmonary tuberculosis

Analysis of HIV-1 genetic subtype and pretreatment drug resistance among men who have sex with men infected with HIV-1 from 19 cities of 6 provinces in China / 中华流行病学杂志

Objective: To investigate the distribution of HIV-1 genetic subtypes and pretreatment drug resistance (PDR) among men who have sex with men (MSM) from 19 cities of 6 provinces in China. Methods: From April to November 2019, 574 plasma samples of ART-naive HIV-1 infected MSM were collected from 19 cities in Hebei, Shandong, Jiangsu, Zhejiang, Fujian, and Guangdong provinces, total ribonucleic acid (RNA) was extracted and amplified the HIV-1 pol gene region by nested polymerase chain reaction (PCR) after reverse transcription. Then sequences were used to construct a phylogenetic tree to determine genetic subtypes and submitted to the Stanford drug resistance database for drug resistance analysis. Results: A total of 479 samples were successfully amplified by PCR. The HIV-1 genetic subtypes included CRF01_AE, CRF07_BC, B, CRF55_01B, CRF59_01B, CRF65_cpx, CRF103_01B, CRF67_01B, CRF68_01B and unrecognized subtype, which accounted for 43.4%, 36.3%, 6.3%, 5.9%, 0.8%, 0.8%, 0.4%, 0.4%, 0.2% and 5.5%, respectively. The distribution of genetic subtypes among provinces is statistically different (χ2=44.141, P<0.001). The overall PDR rate was 4.6% (22/479), the drug resistance rate of non-nucleoside reverse transcriptase inhibitors, nucleoside reverse transcriptase inhibitors, and protease inhibitors were 3.5% (17/479), 0.8% (4/479) and 0.2% (1/479), respectively. The PDR rate of recent infections was significantly higher than that of long-term infections (χ2=4.634, P=0.031). Conclusions: The HIV-1 genetic subtypes among MSM infected with HIV-1 from 19 cities of 6 provinces in China are diverse, and the distribution of subtypes is different among provinces. The overall PDR rate is low, while the PDR rate of recent infections was significantly higher than that of long-term infections, suggesting the surveillance of PDR in recent infections should be strengthened.

Detection of drug resistance genes of mycobacterium tuberculosis by rolling circle amplification technique with multicolor fluorescent probes / 中华预防医学杂志

The aim of this study was to construct a simple, rapid and ultra-sensitive optical biosensing technique based on rolling circle amplification (RCA), and to apply it to multiple detection of drug-resistant genes of mycobacterium tuberculosis. The common mutation sites of isoniazid, rifampicin and streptomycin resistance genes are katG315 (AGC➝ACC), rpoB531 (CAC➝TAC) and rpsL43 (AAG➝AGG). For these three gene sites, from February 2020 to May 2021, in the Department of Laboratory Medicine of the First Affiliated Hospital of Army Military Medical University, the padlock probe (PLP), primers and capture probes were designed. And a solid-phase RCA constant temperature amplification reaction system based on magnetic beads was constructed and the experimental parameters were optimized. The RCA products were accurately captured by the multicolor fluorescent probes (Cy3/Cy5/ROX), and the single-tube multiple detection of three mutation genes was realized. The sensitivity, specificity and linear range of this method were further verified. The results showed that the response range of katG315 in the same reaction system ranged from 1.0 pmol/L to 0.1 nmol/L. The response range of rpoB531 and rpsL43 ranged from 1.0 pmol/L to 50.0 pmol/L and 1.0 pmol/L to 20.0 pmol/L, and the method had good specificity and sensitivity, and could accurately identify single base mutations in mixed targets, with the minimum detection limit as low as 1.0 pmol/L. The recoveries of simulated serum samples were 95.0%-105.2%. In conclusion, the constant temperature amplification multiple detection method constructed in this study can quickly realize the single-tube multiple detection of three drug resistance mutation sites. This technology is low-cost, simple and rapid, and does not rely on large equipment, providing a new analysis method for pathogen drug resistance gene detection.

A real world study on the relationship between drug resistance of targeted therapy and prognosis of HER-2-positive advanced breast cancer / 中华肿瘤杂志

Objective: To explore the effect of primary and acquired resistance to anti-human epidermal growth factor receptor 2 (HER-2) on the overall survival of patients with HER-2 positive advanced breast cancer. Methods: The clinical characteristics of HER-2 positive patients with advanced breast cancer admitted to Cancer Hospital of Chinese Academy of Medical Sciences from January 1998 to December 2018 were collected, and their neoadjuvant/adjuvant and advanced three-line chemotherapy were summarized. Among them, targeted drugs for HER-2 included trastuzumab, pertuzumab, T-DM1, RC48-ADC, lapatinib, pyrotinib, allitinib, sipatinib, seratinib. Based on the duration of benefit from anti HER-2 treatment, the patients were divided into two groups: primary anti HER-2 resistance group and acquired anti HER-2 resistance group. In this study, the overall survival (OS) was used as the main end point. Kaplan-Meier analysis and Cox proportional risk regression model were used to analyze the effects of different drug resistance mechanisms on the overall survival. Results: The whole group of 284 patients were included. The median age of recurrence and metastasis was 48 years old, 155 (54.6%) were hormone receptor (HR) positive and 129 (45.4%) were HR negative, 128 cases (45.1%) were premenopausal and 156 cases (54.9%) were postmenopausal, 277 cases (97.5%) had a score of 0-1 in ECoG PS and 7 cases (2.5%) had a score of more than 2 in the first diagnosis of relapse and metastasis. There were 103 cases (36.3%) in the primary drug resistance group and 181 cases (63.7%) in the secondary drug resistance group. The median overall survival time of the two groups was 24.9 months and 40.4 months, respectively, with statistical significance (P<0.001). Conclusion: Primary resistance to HER-2 is one of the factors of poor prognosis in HER-2 positive breast cancer, and its mechanism needs to be further explored.

Prevalence of antifolate drug resistance markers in Plasmodium vivax in China / 医学前沿

The dihydrofolate reductase (dhfr) and dihydropteroate synthetase (dhps) genes of Plasmodium vivax, as antifolate resistance-associated genes were used for drug resistance surveillance. A total of 375 P. vivax isolates collected from different geographical locations in China in 2009-2019 were used to sequence Pvdhfr and Pvdhps. The majority of the isolates harbored a mutant type allele for Pvdhfr (94.5%) and Pvdhps (68.2%). The most predominant point mutations were S117T/N (77.7%) in Pvdhfr and A383G (66.8%) in Pvdhps. Amino acid changes were identified at nine residues in Pvdhfr. A quadruple-mutant haplotype at 57, 58, 61, and 117 was the most frequent (57.4%) among 16 distinct Pvdhfr haplotypes. Mutations in Pvdhps were detected at six codons, and the double-mutant A383G/A553G was the most prevalent (39.3%). Pvdhfr exhibited a higher mutation prevalence and greater diversity than Pvdhps in China. Most isolates from Yunnan carried multiple mutant haplotypes, while the majority of samples from temperate regions and Hainan Island harbored the wild type or single mutant type. This study indicated that the antifolate resistance levels of P. vivax parasites were different across China and molecular markers could be used to rapidly monitor drug resistance. Results provided evidence for updating national drug policy and treatment guidelines.

Effects of pretreatment HIV drug resistance on the virological response of HIV-infected patients after 3-year antiretroviral therapy / 中华流行病学杂志

Objective: To investigate the impact of pretreatment drug resistance (PDR) on virological effect among HIV-infected patients having received antiretroviral therapy (ART) after three years. Methods: The baseline survey of PDR among HIV-infected patients was conducted in 2018, with a three-year follow up study. The clinic data and virological laboratory test variables were statistically analyzed. Results: Of the 2 433 participants, 41.6% (1 012/2 433) were aged between 18 and 34, 82.8% (2 015/2 433) were males, 46.9% (1 142/2 433) had education of high school or above, 22.4% (544/2 433) were farmers, 33.8% (823/2 433) were unmarried, 48.1% (1 169/2 433) were infected heterosexually and 41.3% (1 004/2 433) were with CRF07_BC. The prevalence of PDR was 4.5% (109/2 433). The prevalence of virological suppression failure (viral load ≥50 copies/ml) and drug resistance at three years follow up after ART was 8.1%(196/2 433) and 2.5%(60/2 433) respectively. The prevalence of virological suppression failure and drug resistance at three years follow up after ART were 18.3% (20/109) and 7.6% (176/2 324), and 4.6% (5/109) and 2.4% (55/2 324) among participants with PDR and non-PDR, respectively. The results of multivariate logistic regression model showed that illiteracy (aOR=3.26, 95%CI: 1.82-5.86), primary and junior high school education (aOR=1.54, 95%CI: 1.09-2.18), CD4+T lymphocyte count <200/μl (aOR=2.77, 95%CI: 1.75-4.37) and CD4+T lymphocyte count 200-499/μl (aOR=1.55, 95%CI: 1.10-2.18) at a three year follow up visit after ART, missed drugs in the past month (aOR=4.24, 95%CI: 2.92-6.17), and PDR (aOR=2.84, 95%CI: 1.67-4.85) were statistically significant with virological suppression failure on treatment. Conclusions: The prevalence of PDR in China at a low level currently, and the virological suppression failure rate is low after three years of ART. It is necessary to strengthen drug resistance monitoring of HIV-infected patients and pay attention to the influence of PDR on treatment effect.

The Effect of hnRNPK/Beclin1 Signaling on the Drug Resistance of Imatinib in Ph+ Leukemia / 中国实验血液学杂志

OBJECTIVE@#To explore the effect of hnRNPK/Beclin1 signaling on the drug resistance of imatinib in Ph+ leukemia.@*METHODS@#Expression level of hnRNPK was verified in the imatinib resistant and sensitive Ph+ leukemia cell lines by using Western blot. hnRNPK expression was down-regulated by using RNAi. Expression level of LC3I/II and Beclin1 were detected by Western blot and the sensitivity of imatinib was analyzed by CCK-8 assay before and after modulation of hnRNPK expression.@*RESULTS@#hnRNPK showed overexpressed in imatinib resistant leukemia cell line. After the expression level of hnRNPK was down-regulated by RNAi, the sensitivity of drug resistance lines to imatinib restored, while the expression level of LC3I/II and Beclin1 were consistant with the modulation of hnRNPK expression.@*CONCLUSION@#hnRNP K/Beclin1 signaling may be involved in the development of imatinib resistance in Ph+ leukemia through the regulation of autophagy.

Establishment of Drug-Resistant Cell Lines of Acute Myeloid Leukemia and Correlation of Sirt1 and PGC-1α Expression Levels with Drug Resistance / 中国实验血液学杂志

OBJECTIVE@#To construct cytarabine-resistant acute myeloid leukemia (AML) cell lines, and explore the correlation between Sirt1, PGC-1α expression levels and drug resistance.@*METHODS@#Human acute promyelocytic leukemia Kasumi-1 cells were induced by the method of gradually increasing the concentration of Ara-C drug. The IC50 value of Kasumi-1 cells before and after drug addition was detected by CCK-8 method, so as to construct Ara-C resistant cell lines. The expression levels of Sirt1 and PGC-1α mRNA in Kasumi-1 drug-resistant cell lines and their parental cell lines were detected by real-time fluorescence quantitative PCR, and the expression levels of Sirt1 and PGC-1α protein in kasumi-1 drug-resistant cell lines and their parental cell lines were detected by Western blot.@*RESULTS@#The constructed Kasumi-1 cell line had common morphological characteristics of drug-resistant cell lines under microscope, and the drug resistance index was greater than 5, indicating that Kasumi-1 drug-resistant cells had good drug resistance after the construction. The RT-qPCR and Western blot assays showed that the expression levels of Sirt1 and PGC-1α mRNA and protein in the drug-resistant cell lines were higher than those of the parental cell lines (P<0.001).@*CONCLUSION@#AML cell lines resistant to Ara-C can be successfully induced by the method of gradually increasing the concentration, and the co-high expression of Sirt1 and PGC-1α may mediate the drug resistance of AML cells.

Lung Cancer Stem-like Cells and Drug Resistance / 中国肺癌杂志

Lung cancer remains the leading cause of cancer-related death world-wide. Therapy resistance and relapse are considered major reasons contributing to the poor survival rates of lung cancer. Accumulated evidences have demonstrated that a small subpopulation of stem-like cells existed within lung cancer tissues and cell lines, possessing the abilities of self-renewal, multipotent differentiation and unlimited proliferation. These lung cancer stem-like cells (LCSCs) can generate tumors with high effeciency in vivo, survive cytotoxic therapies, and eventually lead to therapy resistance and recurrence. In this review, we would like to present recent knowledges on LCSCs, including the origins where they come from, the molecular features to identify them, and key mechanisms for them to survive and develop resistance, in order to provide a better view for targeting them in future clinic.
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Effect of MiR-155 Knockout Mediated by Dual sgRNAs on Drug Sensitivity of FLT3-ITD+AML / 中国实验血液学杂志

OBJECTIVE@#Two sgRNAs transfected FLT3-ITD+AML cell line MV411 with different binding sites were introduced into CRISPR/cas9 to obtain MV411 cells with miR-155 gene knockout. To compare the efficiency of miR-155 gene knockout by single and double sgRNA transfection and their effects on cell phenotypes.@*METHODS@#The lentiviral vectors were generated containing either single sgRNA or dual sgRNAs and packaged into lentivirus particles. PCR was conducted to measure gene editing efficiency, and miR-155 expression was evaluated by qPCR. CCK-8 assay was used to evaluate the cell proliferation, and calculate drug sensitivity of cells to adriamycin and quizartinib. Annexin V-APC/7-AAD staining was used to label cell apoptosis induced by adriamycin and quizartinib.@*RESULTS@#In the dual sgRNAs transfected cells, a cleavage band could be observed, meaning the success of gene editing. Compared with the single sgRNA transfected MV411 cells, the expression level of mature miR-155-5p was lower in the dual sgRNA transfected cells. And, dual sgRNA transfected MV411 were more sensitive to adriamycin and quizartinib with lower IC50 and higher apoptosis rate.@*CONCLUSION@#The inhibition rate of miR-155 gene expression transfected by dual sgRNA is higher than that by single sgRNA. Dual sgRNA transfection can inhibit cell proliferation, reverse drug resistance, and induce apoptosis more significantly. Compared with single sgRNA transfection, dual sgRNA transfection is a highly efficient gene editing scheme.

Construction of EF-G knockdown strain of Mycobacterium smegmatis and drug resistance analysis / 生物工程学报

As the only translational factor that plays a critical role in two translational processes (elongation and ribosome regeneration), GTPase elongation factor G (EF-G) is a potential target for antimicrobial agents. Both Mycobacterium smegmatis and Mycobacterium tuberculosis have two EF-G homologous coding genes, MsmEFG1 (MSMEG_1400) and MsmEFG2 (MSMEG_6535), fusA1 (Rv0684) and fusA2 (Rv0120c), respectively. MsmEFG1 (MSMEG_1400) and fusA1 (Rv0684) were identified as essential genes for bacterial growth by gene mutation library and bioinformatic analysis. To investigate the biological function and characteristics of EF-G in mycobacterium, two induced EF-G knockdown strains (Msm-ΔEFG1(KD) and Msm-ΔEFG2(KD)) from Mycobacterium smegmatis were constructed by clustered regularly interspaced short palindromic repeats interference (CRISPRi) technique. EF-G2 knockdown had no effect on bacterial growth, while EF-G1 knockdown significantly retarded the growth of mycobacterium, weakened the film-forming ability, changed the colony morphology, and increased the length of mycobacterium. It was speculated that EF-G might be involved in the division of bacteria. Minimal inhibitory concentration assay showed that inhibition of EF-G1 expression enhanced the sensitivity of mycobacterium to rifampicin, isoniazid, erythromycin, fucidic acid, capreomycin and other antibacterial agents, suggesting that EF-G1 might be a potential target for screening anti-tuberculosis drugs in the future.

Sunitinib induced resistance of endothelial cells by up-regulating P-glycoprotein and PI3K/Akt pathway

Abstract Drug resistance is a crucial obstacle to achieve satisfactory chemotherapeutic effects. Numerous studies have shown that the PI3K/Akt signaling pathway plays a significant role in various processes of cellular events and tumor progression, while few studies have focused on the PI3K/Akt signaling pathway in drug resistance of endothelial cells. The present study aims to explore the relationship of PI3K/Akt signaling and cellular resistance to anticancer drugs in human microvessel endothelial cells (HMEC-1). We established stable sunitinib-resiatant human microvessel endothelial cells (HMEC-su) after long-term exposure to sunitinib (a small-molecule tyrosine kinase receptor inhibitor) for 12 months. HMEC-su showed significant alternations of cell morphology and exhibited a 2.32-fold higher IC50 of sunitinib than parental HMEC-1 cells. Expression of P-glycoprotein (P-gp) and breast cancer-resistance protein (ABCG2) which mediates drug efflux, increased significantly in HMEC-su lines compared with HMEC-1 cells by western blots assay. Our study further demonstrates that LY294002 (blocking the PI3K/Akt pathway) enhances the sensibility of HMEC-su to suntinib and inhibits the gene transcription and protein expression of P-gp, ABCG2 in HMEC-su cells. In conclusion, these results indicate that LY294002 could reverse P-gp and ABCG2 mediated-drug resistance to sunitinib in HMEC-su cells by inhibiting PI3K/Akt signaling.

Mutación en el gen SCN9Aasociado con el síndrome de Dravet: presentación de un caso pediátrico / Mutation in the SCN9A Gene Associated with Dravet Syndrome: A Pediatric Case Report / Mutação no gene SCN9A associada à síndrome de Dravet: relato de um caso pediátrico

Introducción:el síndrome de Dravet, también conocido como epilepsia mioclónica grave de la infancia, corresponde a una encefalopatía epiléptica resistente a fármacos que inicia generalmente en el primer año de vida. Se caracteriza por crisis epilépticas que suelen tener múltiples desencadenantes; el más asociado es la presencia de episodios febriles previos. Se considera una enfermedad rara, debido a su baja incidencia y prevalencia. Presentación del caso: niño de 10 años de edad con un cuadro de epilepsia de origen estructural, asociada con un retraso en el neurodesarrollo y anomalías craneofaciales meno-res, con antecedente de cardiopatía congénita no corregida, colpocefalia y agenesia del cuerpo calloso. Debido a la persistencia de las crisis convulsivas y su consiguiente resistencia farmacológica, se le rea-lizó un exoma genético que evidenció una mutación del gen SCN9. Discusión: el síndrome de Dravet debe ser sospechado en todo paciente menor de un año que tenga crisis convulsivas a repetición asociadas con episodios febriles cuantificados. Aproximadamente, entre el 70 % y el 85 % de los pacientes con el diagnóstico de síndrome de Dravet presenta una mutación en el gen SCN1A, por lo que mutaciones en otros genes que codifican para canales de sodio, ubicados en el mismo cromosoma, como el SCN9A, podrían contribuir de forma multifactorial a dicha entidad

Introduction: Dravet syndrome, also known as severe myoclonic epilepsy in infancy, is a drug resistant epileptic encephalopathy that usually begins in the first year of life. It is characterized by the presence of epileptic seizures that usually have multiple triggers; the most currently associated is the presence of previous febrile episodes. It is considered as a rare disease due to its low incidence and prevalence. Case presentation: We reported the case of a ten-year-old boy with structural epilepsy associated with a neuro-developmental delay and minor craniofacial anomalies. He had a history of uncorrected congenital heart disease, colpocephaly, and agenesis of the corpus callosum. Due to the persistence of seizures secondary to drug resistance, it was decided to perform a genetic exome that evidenced a mutation of the SCN9A gene. Conclusions: Dravet syndrome should be suspected in all patients under one year of age who have recu-rrent seizures associated with fever that does not respond to medication and modifies its presentation. Approximately 70%−85% of the patients diagnosed with Dravet syndrome have a mutation in the SCN1A gene; therefore, mutations in other genes that encode sodium channels located on the same chromosome, such as SCN9A, could contribute in a multifactorial way.

Introdução: a síndrome de Dravet, também conhecida como epilepsia mioclônica grave da infância, corresponde a uma encefalopatia epiléptica resistente a medicamentos que geralmente se inicia no primeiro ano de vida. É caracterizada pela presença de crises epilépticas que costumam ter múltiplos detonantes, sendo que o mais associado atualmente é a presença de episódios febris prévios. É conside-rada uma doença rara devido à sua baixa incidência e prevalência. Apresentação do caso: é apresentado o caso de um menino de 10 anos de idade com quadro de epilepsia de origem estrutural, associada a atraso no desenvolvimento neurológico e pequenas anomalias craniofaciais; com histórico de cardio-patia congênita não corrigida, colpocefalia e agenesia do corpo caloso. Devido à persistência das crises epilépticas e consequente resistência farmacológica, optou-se pela realização de um exoma genético que apresenta uma mutação do gene SCN9. Discussão: a síndrome de Dravet deve ser suspeitada em todos os pacientes com menos de um ano de idade que apresentam convulsões repetidas associadas a episódios febris quantificados. Aproximadamente 70 a 85% dos pacientes com diagnóstico de síndrome de Dravet apresentam mutação no gene SCN1A, portanto mutações em outros genes que codificam canais de sódio, localizados no mesmo cromossomo, como o SCN9A, poderiam contribuir de forma multifatorial para essa entidade

Estructura genética de cepas de Mycobacterium tuberculosis farmacorresistentes en Perú con base en haplotipos obtenidos de un ensayo de sonda lineal / Genetic structure of drug-resistant strains of Mycobacterium tuberculosis in Peru based on haplotypes obtained from a linear probe assay

RESUMEN Objetivo. Determinar la estructura genética de las cepas drogorresistentes de Mycobacterium tuberculosis que circularon en todo el Perú durante los años 2011-2015 a través de haplotipos obtenidos de un ensayo con sondas en línea. Materiales y métodos. Se analizaron 6589 muestras que ingresaron al Instituto Nacional de Salud para el diagnóstico rutinario mediante el ensayo GenoType® MTBDRplus v2, durante el periodo de estudio. Se crearon haplotipos resistentes mediante la concatenación de 21 sitios polimórficos de los genes evaluados por el ensayo con sondas en línea, y se realizó el análisis de asociación con fenotipos obtenidos por el método de proporciones agar 7H10. Resultados. Las mutaciones de mayores frecuencias fueron: rpoB S531L (55,4%) y rpoB D516V (18,5%) para la resistencia a rifampicina, y katG S315T (59,5%) e inhA c-15t (25,7%) para la resistencia a isoniacida. Se obtuvieron 13 haplotipos representativos (87,8% de muestras analizadas) de los cuales seis correspondieron al genotipo multidrogorresistente, cuatro al genotipo monorresistente a isoniacida y tres al genotipo monorresistente a rifampicina. Dieciocho departamentos, y la provincia del Callao, presentaron una alta diversidad haplotípica; cuatro presentaron moderada diversidad y dos presentaron baja diversidad. Conclusiones. Existe una alta diversidad haplotípica en la mayoría de los departamentos, además de una concentración de las cepas de Mycobacterium tuberculosis drogorresistentes en las ciudades de Lima y Callao. Asimismo, las cepas de Mycobacterium tuberculosis con perfil drogorresistente que circulan en el Perú contienen principalmente los marcadores genéticos de mayor prevalencia a nivel mundial asociados con la resistencia frente a rifampicina e isoniacida.

ABSTRACT Objective. To determine the genetic structure of drug-resistant strains of Mycobacterium tuberculosis that circulated throughout Peru during the years 2011-2015, by using haplotypes obtained from a line probe assay. Materials and methods. A total of 6589 samples that were admitted to the Instituto Nacional de Salud for routine diagnosis using the GenoType® MTBDRplus v2 assay were analyzed during the study period. Resistant haplotypes were created by concatenating 21 polymorphic sites of the evaluated genes using the line probe assay; and the association analysis was carried out with phenotypes obtained by the 7H10 agar ratio method. Results. The most frequent mutations were: rpoB S531L (55.4%) and rpoB D516V (18.5%) for rifampicin resistance, and katG S315T (59.5%) and inhA c-15t (25.7%) for isoniazid resistance. We obtained 13 representative haplotypes (87.8% of analyzed samples), 6 corresponded to the multidrug-resistant genotype, 4 to the isoniazid mono-resistant genotype and 3 to the rifampicin mono-resistant genotype. Eighteen regions and the province of Callao showed high haplotype diversity; four showed moderate diversity and two showed low diversity. Conclusions. Most regions showed high haplotype diversity; in addition, most drug-resistant strains of Mycobacterium tuberculosis were concentrated in the cities of Lima and Callao. Likewise, drug-resistant Mycobacterium tuberculosis strains circulating in Peru mainly contain the genetic markers with the highest prevalence worldwide, which are associated with resistance to rifampicin and isoniazid.

Caracterización molecular de genes de virulencia (lmb, bca y rib) y de resistencia a macrólidos (ermB, ermTR y mefA) en aislamientos clínicos de Streptococcus agalactiae / Molecular characterization of virulence (lmb, bca and rib) and macrolid resistance genes (ermB, ermTR and mefA) in clinical isolates of Streptococcus agalactiae

RESUMEN El objetivo del estudio fue identificar molecularmente los genes de virulencia y resistencia a macrólidos en aislamientos clínicos de Streptococcus agalactiae (EGB), recuperados en 2019 a partir de secreción vaginal (n=9) y orina (n=22), en dos establecimientos de salud de Lima. La identificación y susceptibilidad antimicrobiana se determinaron por el sistema automatizado Vitek® 2, se confirmó la identificación fenotípicamente; la resistencia a macrólidos por el método D-test; la identificación de genes de virulencia (lmb, bca y rib) y de resistencia a macrólidos (ermB, ermTR y mefA) por reacción en cadena de la polimerasa (PCR). El fenotipo y genotipo de resistencia a macrólidos predominante fue cMLSb (12/31) y ermB (11/31), y el gen de virulencia más frecuente fue lmb (23/31). Todos fueron sensibles a penicilina, ampicilina y vancomicina. Estos hallazgos muestran la necesidad de implementar estudios de epidemiología molecular que permitan un adecuado conocimiento y seguimiento de EGB en el Perú.

ABSTRACT The aim of the study was to molecularly identify virulence and macrolide resistance genes in clinical isolates of Streptococcus agalactiae (GBS), recovered in 2019 from vaginal discharge (n=9) and urine (n=22), from two health facilities in Lima. Identification and antimicrobial susceptibility were determined by the Vitek® 2 automated system, identification was confirmed phenotypically; macrolide resistance was determined by the D-test method. Identification of virulence genes (lmb, bca and rib) and macrolide resistance genes (ermB, ermTR and mefA) was carried out by polymerase chain reaction (PCR). The predominant macrolide resistance phenotype and genotype were cMLSb (12/31) and ermB (11/31); the most frequent virulence gene was lmb (23/31). All were sensitive to penicillin, ampicillin and vancomycin. These findings show the need to implement molecular epidemiology studies that allow adequate knowledge and follow-up of GBS in Peru.