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1.
Braz. j. biol ; 83: e248975, 2023. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1339377

ABSTRACT

Abstract Colletotrichum is one of the most economically important fungal genera, which affects a wide range of hosts, specifically tropical and subtropical crops. Thus far, there have been several records of mycovirus infection in Colletotrichum spp., primarily by viruses of the Partitiviridae family. There have also been records of infections by mycoviruses of the Chrysoviridae family. Mycoviruses are (+)ssRNA and dsRNA genome viruses, which may or may not be enveloped. To date, no mycovirus with a DNA genome has been isolated from Colletotrichum spp. Typically, mycoviruses cause latent infections, although hypo- and hypervirulence have also been reported in Colletotrichum spp. In addition to its effects on pathogenic behavior, mycovirus infection can lead to important physiological changes, such as altered morphological characteristics, reduced vegetative growth, and suppressed conidia production. Therefore, research on mycoviruses infecting phytopathogenic fungi can help develop alternative methods to chemical control, which can cause irreversible damage to humans and the environment. From an agricultural perspective, mycoviruses can contribute to sustainable agriculture as biological control agents via changes in fungal physiology, ultimately resulting in the total loss of or reduction in the virulence of these pathogens.


Resumo Colletotrichum é um dos gêneros fúngicos mais importantes economicamente, afetando uma ampla gama de hospedeiros, especialmente em cultivos tropicais e subtropicais. Atualmente já existem diversos registros de infecção por micovírus em Colletotrichum spp., sendo a maioria dos já identificados classificados na família Partitiviridae. Ocorrem registros também de micovírus pertencentes à família Chrysoviridae. Compreendem vírus de genoma de (+)ssRNA e dsRNA que podem ser ou não envelopados. Ainda não foram identificados micovírus com genoma de DNA isolados de Colletotrichum. A infecção por micovírus pode ocorrer de forma latente, mas já foi observado em Colletotrichum spp. o fenômeno de hipo e hipervirulência. Além de influenciar no comportamento patogênico, a infecção pode causar mudanças fisiológicas importantes como alterações das características morfológicas, redução do crescimento vegetativo e redução na produção de conídios. O estudo com micovírus em fungos fitopatogênicos traz uma alternativa ao controle químico que é um método capaz de causar danos irreversíveis ao homem e o meio ambiente. Sob a perspectiva agrícola, os micovírus podem contribuir para agricultura sustentável como agentes de controle biológico. Isso porque obsevam-se mudanças importantes na fisiologia fúngica resultando na perda total ou redução da virulência desses patógenos.


Subject(s)
Humans , RNA Viruses , Colletotrichum , Fungal Viruses/genetics , Phylogeny , Spores, Fungal , Virulence
2.
ABCS health sci ; 47: e022203, 06 abr. 2022. tab, graf
Article in English | LILACS | ID: biblio-1363538

ABSTRACT

INTRODUCTION: Contamination of cell phones can contribute to the dissemination of pathogens in the community and/or hospital environment. OBJECTIVE: To characterize Staphylococcus aureus strains isolated from cell phones of university students. METHODS: Samples were collected from 100 cell phones. Detection of genes associated with virulence factors such as biofilm formation (icaA and icaD), enterotoxins production (SEA, SEB, SEC, and SED), and resistance to methicillin (mecA and mecC) was performed in S. aureus isolates by PCR. Typing mecA gene performed by multiplex PCR. Susceptibility to antimicrobials and biofilm formation rate also evaluated by using disk diffusion test and crystal violet staining. RESULTS: S. aureus was present in 40% of the total samples and about 70% of them belonged to Nursing students. Of the isolates, 85% presented resistance to penicillin and 50% were classified as moderate biofilm producers. In addition, 92.5% of isolates contained the gene icaA and 60% of the gene icaD. Approximately 25% of the isolates presented the mecA gene. Typing of the mecA gene showed the presence of staphylococcal chromosome cassette SCCmec I and c III respectively in 20% and 10% of the isolates. 70% of the samples could not be typed by the technique. Regarding the enterotoxins, the most prevalent gene was SEA (30%) followed by the SEC gene (2.5%). The presence of SED and SEB genes not observed in any of the isolates. CONCLUSION: The cleaning and periodic disinfection of cell phones can contribute to the reduction of the risk of nosocomial infection.


INTRODUÇÃO: A contaminação de celulares pode contribuir para a disseminação de patógenos na comunidade e/ou ambiente hospitalar. OBJETIVO: Caracterizar cepas de Staphylococcus aureus de telefones celulares de estudantes universitários. MÉTODOS: Foram coletadas amostras de 100 telefones celulares. Detecção de genes associados a fatores de virulência quanto a: formação de biofilme (icaA e icaD), produção de enterotoxinas (SEA, SEB, SEC e SED) e resistência à meticilina (mecA e mecC) foi realizada em isolados de S. aureus por PCR. A Tipagem do gene mecA foi realizada por PCR multiplex. A susceptibilidade a antimicrobianos e a taxa de formação de biofilme pelo teste de difusão em disco e coloração com cristal violeta. RESULTADOS: S. aureus esteve presente em 40% do total de amostras, destas, 70% pertenciam a estudantes do curso de enfermagem. Dos isolados, 85% apresentaram resistência à penicilina e 50% foram classificados com moderada formação de biofilme. Além disso, 92,5% dos isolados continham o gene icaA e 60% o gene icaD. Aproximadamente 25% dos isolados apresentaram o gene mecA. A tipagem do gene mecA mostrou a presença do cassete cromossômico estafilocócico SSCmec I e III em respectivamente 20% e 10% dos isolados. 70% das amostras não puderam ser identificadas pela técnica. Das enterotoxinas, o gene mais prevalente foi o SEA (30%), seguido pelo gene SEC (2.5%). A presença dos genes SED e SEB não foi observada nos isolados. CONCLUSÃO: A limpeza e desinfecção periódica dos telefones celulares podem contribuir para a redução do risco de infecção nosocomiais.


Subject(s)
Students, Health Occupations , Universities , Cell Phone , Methicillin-Resistant Staphylococcus aureus , Virulence , Drug Resistance, Microbial , Biofilms , Enterotoxins
3.
São Paulo; s.n; 2022. 104 p.
Thesis in Portuguese | LILACS | ID: biblio-1401032

ABSTRACT

Enterococcus spp. são bactérias caracterizadas como cocos Gram-positivos, frequentemente encontradas na microbiota normal do trato gastrointestinal de seres humanos e animais homeotermos, também sendo encontradas em solos, águas e plantas. Esses micro-organismos são considerados importantes indicadores de contaminação fecal para águas marinhas, e embora sejam descritos como comensais, podem estar associados a uma grande variedade de infecções humanas. A habilidade de adquirirem resistência a antimicrobianos além de sua resistência intrínseca, bem como o contexto de crescimento desfreado de cidades, consumo cada vez maior de antibióticos e poluição das águas, constituem fatores cruciais para que os enterococcus sejam considerados organismos relevantes para a saúde pública global. Dessa forma, o objetivo deste estudo foi caracterizar o perfil fenotípico e genotípico de resistência antimicrobiana e virulência em três espécies de Enterococcus isoladas de águas recreacionais costeiras em praias do estado de São Paulo. Para este projeto foram selecionadas quatro praias do litoral do estado de São Paulo, que são monitoradas pela CETESB como parte do programa de balneabilidade das praias paulistas. As placas contendo colônias de enterococos isoladas em ágar mEI foram levadas para o Laboratório de Microbiologia Ambiental e Resistência Antimicrobiana (MicroRes) da Faculdade de Saúde Pública/USP quinzenalmente de junho de 2019 até março de 2020. A identificação e triagem das espécies de enterococos foi realizada pela técnica de MALDI-TOF MS, e posteriormente os isolados identificados como E. faecium, E. faecalis e E. hirae foram selecionados para confirmação de espécie pela técnica de PCR convencional. Após confirmação foi avaliada a susceptibilidade à antimicrobianos de uso comum. Posteriormente foi realizada a detecção de genes de resistência e virulência nessas três espécies. Em 90,7% dos isolados se observou resistência a pelo menos 1 dos 14 antimicrobianos testados, e em 41,5% se obversou resistência a pelo menos três antimicrobianos de classes diferentes e índice MAR superior a 0,2 sendo, portanto, classificados como multirresistentes (MDR). A maioria dos isolados de enterococos demonstraram resistência a rifampicina (39,2%). Genes que conferem resistência à classe dos macrolídeos (ermB) e às tetraciclinas (tetM e tetL) foram os mais prevalentes entre os isolados, com 14,6% e 12,3% respectivamente. Os isolados da espécie E. faecalis apresentaram positividade a pelo menos 1 dos 5 marcadores de virulência testados. Isolados de E. faecalis apresentaram um perfil de virulência mais diversificado quando comparados aos isolados de E. faecium e E. hirae. A presença de estirpes com múltipla resistência aos antimicrobianos somada a positividade para outros fatores de virulência pode ser indicativa de risco para a saúde pública se essas estirpes chegarem a atingir as áreas de praia utilizadas por banhistas, reforçando a importância de estudos conduzidos em águas recreacionais.


Enterococcus spp. are bacteria characterized as Gram-positive cocci, often found in the normal microbiota of the gastrointestinal tract of humans and homeotherm animals, in soils, water and plants. These microorganisms are considered important indicators of fecal contamination for marine waters, and although they are described as commensals, they can be associated with a wide variety of human infections. The ability to acquire antimicrobial resistance in addition to their intrinsic resistance, as well as the context of uncontrolled growth of cities, increasing consumption of antibiotics and water pollution, are crucial factors for enterococci to be considered relevant organisms for public health. Thus, the aim of this study was to characterize the phenotypic and genotypic profile of antimicrobial resistance and virulence in three Enterococcus species isolated from coastal recreational waters on beaches in the state of São Paulo. For this project, four beaches were selected, which are monitored by CETESB as part of the balneability program. The plates containing colonies of enterococci were taken to the Laboratory of Environmental Microbiology and Antimicrobial Resistance (MicroRes) of the Faculdade de Saúde Pública/USP fortnightly from June 2019 to March 2020. The identification and screening of enterococci species were performed by the MALDI-TOF MS technique, and later the isolates identified as E. faecium, E. faecalis and E. hirae were selected for species confirmation using conventional PCR technique. After confirmation, susceptibility to antimicrobials was evaluated. Subsequently, it was performed the detection of resistance and virulence genes in these three species. In 90.7% of the isolates we observed resistance to at least 1 of the 14 antimicrobials tested, and in 41.5% resistance was observed to at least three antimicrobials of different classes and a MAR index greater than 0.2, therefore, classified as multidrug resistant (MDR). Most enterococci showed resistance to rifampicin (39.2%). Genes that confer resistance to the macrolide (ermB) and to tetracycline (tetM and tetL) were the most prevalent among the isolates, with 14.6% and 12.3% respectively. E. faecalis strains were positive for at least 1 of the 5 virulence markers tested. E. faecalis isolates showed a more diverse virulence profile when compared to E. faecium and E. hirae isolates. The presence of strains with multiple antimicrobial resistance added to positivity for other virulence factors may indicate a risk to public health if these strains reach the beach areas used by bathers, reinforcing the importance of studies conducted in recreational waters.


Subject(s)
Virulence , Drug Resistance, Microbial , Coastal Water , Recreational Water , Enterococcus
4.
Article in English | WPRIM | ID: wpr-929062

ABSTRACT

The aquatic grass Zizania latifolia grows symbiotically with the fungus Ustilago esculenta producing swollen structures called Jiaobai, widely cultivated in China. A new disease of Z. latifolia was found in Zhejiang Province, China. Initial lesions appeared on the leaf sheaths or sometimes on the leaves near the leaf sheaths. The lesions extended along the axis of the leaf shoots and formed long brown to dark brown streaks from the leaf sheath to the leaf, causing sheath rot and death of entire leaves on young plants. The pathogen was isolated and identified as the bacterium Pantoea ananatis, based on 16S ribosomal RNA (rRNA) gene sequencing, multilocus sequence analysis (atpD (β-subunit of ATP synthase F1), gyrB (DNA gyrase subunit B), infB (translation initiation factor 2), and rpoB (β‍-subunit of RNA polymerase) genes), and pathogenicity tests. Ultrastructural observations using scanning electron microscopy revealed that the bacterial cells colonized the vascular tissues in leaf sheaths, forming biofilms on the inner surface of vessel walls, and extended between vessel elements via the perforated plates. To achieve efficient detection and diagnosis of P. ananatis, species-specific primer pairs were designed and validated by testing closely related and unrelated species and diseased tissues of Z. latifolia. This is the first report of bacterial sheath rot disease of Z. latifolia caused by P. ananatis in China.


Subject(s)
Pantoea/genetics , Plant Diseases/microbiology , Poaceae/microbiology , Virulence
5.
Protein & Cell ; (12): 422-445, 2022.
Article in English | WPRIM | ID: wpr-939868

ABSTRACT

Aging-induced changes in the immune system are associated with a higher incidence of infection and vaccination failure. Lymph nodes, which filter the lymph to identify and fight infections, play a central role in this process. However, careful characterization of the impact of aging on lymph nodes and associated autoimmune diseases is lacking. We combined single-cell RNA sequencing (scRNA-seq) with flow cytometry to delineate the immune cell atlas of cervical draining lymph nodes (CDLNs) of both young and old mice with or without experimental autoimmune uveitis (EAU). We found extensive and complicated changes in the cellular constituents of CDLNs during aging. When confronted with autoimmune challenges, old mice developed milder EAU compared to young mice. Within this EAU process, we highlighted that the pathogenicity of T helper 17 cells (Th17) was dampened, as shown by reduced GM-CSF secretion in old mice. The mitigated secretion of GM-CSF contributed to alleviation of IL-23 secretion by antigen-presenting cells (APCs) and may, in turn, weaken APCs' effects on facilitating the pathogenicity of Th17 cells. Meanwhile, our study further unveiled that aging downregulated GM-CSF secretion through reducing both the transcript and protein levels of IL-23R in Th17 cells from CDLNs. Overall, aging altered immune cell responses, especially through toning down Th17 cells, counteracting EAU challenge in old mice.


Subject(s)
Aging , Animals , Autoimmune Diseases , Disease Models, Animal , Granulocyte-Macrophage Colony-Stimulating Factor/metabolism , Mice , Mice, Inbred C57BL , Th17 Cells/metabolism , Uveitis/pathology , Virulence
6.
Article in Chinese | WPRIM | ID: wpr-928106

ABSTRACT

Brown rot is a common disease in the cultivation and production of Gastrodia elata, but its pathogens have not been fully revealed. In this study, the pathogenic fungi were isolated and purified from tubers of 77 G. elata samples with brown rot. Pathogens were identified by the pathogenicity test and morphological and molecular identification. The pathogenicity of each pathogen and its inhibitory effects on Armillaria gallica were compared. The results showed that 119 strains of fungi were isolated from tubers of G. elata infected with brown rot. Among them, the frequency of separation of Ilyonectria fungi was as high as 42.01%. The pathogenicity test showed that the pathogenicity characteristics of six strains of fungi were consistent with the natural symptoms of brown rot in G. elata. The morphological and molecular identification results showed that the six strains belonged to I. cyclaminicola and I. robusta in the Nectriaceae family of Sordariomycetes class, respectively. Both types of fungi could produce pigments, conidia, and chlamycospore, and the growth rate of I. cyclaminicola was significantly higher than that of I. robusta. The comparison of pathogenicity showed that the spots formed by I. cyclaminicola inoculation were significantly larger than those of I. robusta inoculation, suggesting I. cyclaminicola was superior to I. robusta in pathogenicity. The results of confrontation culture showed that I. cyclaminicola and I. robusta could signi-ficantly inhibit the germination and cordage growth of A. gallica. A. gallica also inhibited the growth of pathogens, and I. cyclaminicola was less inhibited as compared with I. robusta. The results of this study revealed for the first time that I. cyclaminicola and I. robusta were the pathogens responsible for G. elata brown rot.


Subject(s)
Fungi , Gastrodia , Plant Tubers , Spores, Fungal , Virulence
7.
Braz. j. biol ; 82: e250778, 2022. tab, graf
Article in English | LILACS, VETINDEX | ID: biblio-1285589

ABSTRACT

Abstract Entomopathogenic fungi (EPF) now a possible safer microbial control measure that could be considered as a substitute for chemical control of insect pests. Three EPF viz., Metarihizium anisopliae, Isaria furnosoroseus and Beauveria bassiana were evaluated for their virulence against the grubs of Khapra beetle, Trogoderma granarium (Everts) under laboratory conditions. The isolates were applied by two methods viz., diet incorporation and an immersion method with 3rd instar 20 grubs of T. granarium for each. The virulence of EPF was determined using percent mortality. Significantly higher mortality was observed in M. anisopliae applied through immersion (98.33%) and diet incorporation (93.33%) methods followed by B. bassiana (90.83 and 85.83%, respectively). The mortality caused by I. furnosoroseus was statistically lower in immersion and diet incorporation methods i.e. 81.67 and 73.33%, respectively. Based on the immersion method, all EPF were studied for multiple conidial concentration i.e., 1×104, 1×105, 1×106, 1×107 and 1×108 under the same in-vitro conditions. All the isolates were pathogenic to grub of T. granarium at the highest conidial concentration. M. anisopliae was proved the most effective virulent resulting in 98.33% mortality of the pest with LT50 4.61 days at 1 × 108 conidial concentration followed by 90.83 and 81.67 percent mortality with 5.07 and 8.01 days LT50, in the application of B. bassiana and I. furnosoroseus, respectively. M. anisopliae showed higher efficacy and could be considered as promising EPF for the development of myco-insecticides against effective biocontrol of T. granarium.


Resumo Os fungos entomopatogênicos (FPE) são agora a possível medida de controle microbiano mais segura, que pode ser considerada um substituto para o controle químico de pragas de insetos. Três EPF viz., Metarihizium anisopliae, Isaria furnosoroseus e Beauveria bassiana foram avaliados quanto à sua virulência contra as larvas do besouro Khapra, Trogoderma granarium (Everts) em condições de laboratório. Os isolados foram aplicados por dois métodos, a saber: incorporação de dieta e um método de imersão com 20 larvas de T. granarium de 3º ínstar para cada um. A virulência do EPF foi determinada usando a mortalidade percentual. Mortalidade significativamente maior foi observada em M. anisopliae aplicado pelos métodos de imersão (98,33%) e incorporação de dieta (93,33%), seguido por B. bassiana (90,83% e 85,83%, respectivamente). A mortalidade causada por I. furnosoroseus foi estatisticamente menor nos métodos de imersão e incorporação de dieta, ou seja, 81,67% e 73,33%, respectivamente. Com base no método de imersão, todos os EPFs foram estudados para múltiplas concentrações de conídios, ou seja, 1 × 104, 1 × 105, 1 × 106, 1 × 107 e 1 × 108 nas mesmas condições in vitro. Todos os isolados foram patogênicos à larva de T. granarium na maior concentração de conídios. M. anisopliae provou ser o virulento mais eficaz, resultando em 98,33% de mortalidade da praga com LT50 4,61 dias na concentração de 1 × 108 conídios seguido por 90,83% e 81,67% de mortalidade com 5,07 e 8,01 dias LT50, na aplicação de B. bassiana e I. furnosoroseus, respectivamente. M. anisopliae apresentou maior eficácia e pode ser considerada como um PFE promissor para o desenvolvimento de micoinseticidas contra o biocontrole efetivo de T. granarium.


Subject(s)
Animals , Oryza , Coleoptera , Beauveria , Virulence , Pest Control, Biological , Larva
8.
Bol. micol. (Valparaiso En linea) ; 36(2): 14-19, dic. 2021.
Article in Spanish | LILACS | ID: biblio-1352557

ABSTRACT

Ha surgido una nueva variante de preocupación de SARS-CoV-2, cuyos efectos en la evolución de la pandemia parecen inciertos. Sin embargo, ha comenzado a surgir evidencia con respecto al comportamiento viral en cuanto a su transmisibilidad, unión a receptor de la célula hospedadora y escape del sistema inmune. Presentamos una revisión actualizada de los datos existentes en la literatura respecto a los aspectos microbiológicos y epidemiológicos que pueden ayudarnos a comprender las futuras investigaciones en esta variante.(AU)


A new variant of concern for SARS-CoV-2 has emerged, the effects of which on the evolution of the pandemic appear uncertain. However, evidence has begun to emerge regarding viral behavior in terms of its transmissibility, receptor binding on the host cell, and escape from the immune system. We present an updated review of the existing data in the literature regarding the microbiological and epidemiological aspects that can help us understand future research on this variant.(AU)


Subject(s)
Evolution, Molecular , SARS-CoV-2/genetics , Virulence , Behavior , SARS-CoV-2/pathogenicity , COVID-19/epidemiology
9.
Rev. psicanal ; 28(1): 103-120, Abril 2021.
Article in Portuguese | LILACS | ID: biblio-1252999

ABSTRACT

O presente trabalho parte da ideia de caracterizar o disruptivo no pensamento freudiano. Como ponto de partida, toma o trabalho de 1914, À guisa de introdução ao narcisismo, por reconhecer nele um momento primeiro de ruptura na teoria pulsional vigente: libido do Eu versus libido objetal. Durante o trajeto, sinaliza marcas desse processo e direciona-se para o disruptivo que se instala em termos metapsicológicos, com maior consistência, com o advento da pulsão de morte. A pulsão de destruição, como agente do disruptivo em sua relação com Eros, desenhará caminhos que permitem vislumbrar destinos tanáticos ou criativos. Com essa concepção metapsicológica como indicador, busca-se refletir a respeito da interação entre o disruptivo da pandemia viral e o disruptivo da virulência do racismo e seus desdobramentos criativos na efetivação, pelo coletivo da humanidade, de posturas antirracistas. Tal contexto alberga uma interrogação pontual: como a pandemia, em seu efeito disruptivo, está relacionada com a percepção em toda a sua sensorialidade, em grande escala, de norte a sul, daquilo que mantinha-se parcialmente silencioso e invisível, o racismo? (AU)


The present article begins from the idea of characterize the disruptive in the freudian's thoughts. Is takes as a starter point the work of 1914, On narcissism: an introduction, for recognize it as a first moment of rupture in the current drive theory: self libido versus object libido. In this path, it signals marks of this process and orientate to the disruptive that develops in metapsychological terms, with great consistency, with the advent of the death drive. The destruction drive, as a disruptive agent, in its relation with Eros, will draw paths that allow glimpse its tanatic fate or criative fate. From this metapsychological conception, as an indicator, seeks to reflect the interaction between the disruptive in the viral pandemic and the disruptive in the racism virulence, and its criatives developments in the effectuation of anti-racist postures, by the humanity collective. Context that holds an punctual interrogation: how the pandemic, with its disruptive effect, is related with the perception in all its sensoriality, in big scale, from north to south, with what was, in part, silence and inivisible: the racism? (AU)


El objetivo inicial del presente trabajo es caracterizar lo disruptivo en el pensamiento freudiano. Se toma como punto de partida el célebre texto de 1914 Introducción del narcisismo por reconocer en él un primer momento de ruptura en la teoría pulsional vigente hasta ese momento, que distinguía la libido del Yo y la libido de objeto. En ese recorrido, se irán señalando marcas de dicho proceso orientándose hacia lo disruptivo, que se instalará con mayor consistencia, en términos metapsicológicos, con el advenimiento de la pulsión de muerte. La pulsión de destrucción, como agente de lo disruptivo, en su relación con Eros, trazará caminos que permiten vislumbrar sus destinos tanáticos o creativos. Tomando esa concepción metapsicológica como indicador, busco reflejar la interacción entre lo disruptivo de la pandemia viral y lo disruptivo de la virulencia del racismo, así como sus desdoblamientos creativos en la adopción de posturas antirracistas por parte del colectivo humano. En este contexto se plantea una interrogación puntual: ¿cómo la pandemia, con su efecto disruptivo, está relacionada con la percepción en toda su sensorialidad, en gran escala, de norte a sur, de aquello que, en parte, se mantenía silencioso e invisible, el racismo?


Subject(s)
Pandemics/prevention & control , Racism/psychology , Rupture/psychology , Virulence , Drive , Narcissism
10.
Infectio ; 25(1): 33-38, ene.-mar. 2021. tab, graf
Article in Spanish | LILACS, COLNAL | ID: biblio-1154399

ABSTRACT

Resumen Objetivo: Aislar STEC en las heces del ganado bovino en el municipio de Ulloa, Valle del Cauca y detectar factores de virulencia asociados con la patogénesis. Materiales y métodos: Se tomaron 21 muestras provenientes de bovinos, las cuales fueron tomadas directamente del recto del animal mediante hisopos. Las muestras se procesaron hasta obtener colonias puras a las cuales se les evaluó la presencia de los genes stx1, stx2, eae, saa y hlyA mediante PCR y posteriormente, se evaluó el efecto citotóxico de las muestras positivas sobre células Vero (ATCC-CCL-81.4). Resultados: De las 21 muestras de heces de bovinos,12 presentaron bacterias con uno o ambos genes stx. Se obtuvieron 106 aislamientos totales de STEC y se observaron diferencias en cuanto a la presencia y ausencia de los genes de virulencia evaluados en los aislamientos de cada bovino, obteniendo cinco combinaciones de genes. 48 aislamientos presentaron únicamente el gen stx2 y 58 presentaron tanto el gen stx1 como el gen stx2; de los 106 aislamientos, se detectaron 44 con el gen hlyA y 57 con el gen saa. Conclusiones: Todos los sobrenadantes de STEC analizados mostraron actividad citotóxica sobre las células Vero, mientras que en ausencia de STEC las células formaron monocapa después de 48 h de incubación. Este trabajo es el primer reporte en Colombia que aporta información sobre la presencia de STEC en el ganado bovino, la presencia de factores de virulencia y el potencial efecto citotóxico que poseen estas cepas nativas.


Abstract Objective: To isolate STEC in stool samples from cattle in Ulloa, Valle del Cauca, and to detect virulence factors associated with its pathogenesis. Materials and methods: We took 21 samples from cattle, which were taken directly from the rectum of the animal using swabs. The samples were processed until obtaining pure colonies and evaluated for the presence of the stx1, stx2, eae, saa and hlyA genes by PCR. Afterward, the cytotoxic effect of positive samples were evaluated on Vero cells (ATCC-CCL- 81.4). Results: We observed that from the 21 stools samples, 12 presented bacteria with one or both stx genes. A total of 106 isolates of STEC were obtained and differences among each other were observed regarding the presence and absence of the virulence genes, obtaining five combinations of genes. We found that 48 isolates presented only stx2 gene and 58 presented both the stx1 and stx2 gene. Regarding the other virulence genes, the hlyA gene was detected in 44 isolates and the saa gene was detected in 57 isolates. Conclusions: All the STEC supernatants showed cytotoxic activity on Vero cells, while in its absence the cells formed monolayer after 48 h of incubation. This work is the first report in Colombia that provides information about the presence of STEC in stool cattle, virulence genes and its potential cytotoxic effect in native strains.


Subject(s)
Animals , Cattle , Shiga Toxin , Escherichia coli , Shiga-Toxigenic Escherichia coli , Feces , Livestock , Bacteria , Virulence , Polymerase Chain Reaction
12.
Braz. j. biol ; 81(1): 189-194, Feb. 2021. tab, graf
Article in English | LILACS | ID: biblio-1153306

ABSTRACT

Abstract Many Solidarity Economic Venture (SEV) are family farmers who seek to add value to production through artisanal processing, which can lead to food contamination. Thus, this study aimed to genotypically characterize thermotolerant coliforms (TtC) strains from food produced by local agribusinesses of SEV during January to April 2019. Samples from thirteen production units (PU) from the SEV were submitted to a microbiological analysis of thermotolerant coliforms (AFNOR 3M1/2 - 09/89), using a fast count method in Petrifilm™ dishes. The Polymerase Chain Reaction (PCR) technique was used to verify the following virulence genes (VGs) associated with Escherichia coli: stx, typical from enterohemorrhagic E. coli (EHEC); bfpA typical from entheropathogenic E. coli (EPEC) and elt and slt, typical from entherotoxigenic E. coli (ETEC). The results showed that two samples of queijadinha (typical Brazilian candy made with eggs and coconut) and one sample of cassava cake presented characteristic colonies TtC. This way, three strains were isolated in order to perform the PCR technique. However, the genes used in the reaction were not detected in the isolated strains. Therefore, it is suggested that the isolated strains are from E. coli pathotypes with different virulence genes than the ones analyzed belong other types of TtC, such as Enterobacter and Klebsiella. Although the virulence of genes has not been confirmed, the presence of TtC on food indicates hygiene flaws during production and, therefore, measurements to control and prevent contamination should be taken.


Resumo Muitos Empreendimentos Econômicos Solidários (EES) são formados por agricultores familiares que buscam agregar valor à produção por meio do beneficiamento artesanal, que pode ocasionar a contaminação dos alimentos. Desta forma, este estudo objetivou caracterizar genotipicamente coliformes termotolerantes (CT) isolados em alimentos produzidos por agroindústrias de um EES no período de janeiro a abril de 2019. Então, foi realizada análise microbiológica de coliformes termotolerantes (AFNOR 3M1/2 - 09/89), utilizando um método contagem de contagem rápida em placas Petrifilm™, em amostras de alimentos de treze Unidades de Produção (UP) do EES. Foram coletadas assepticamente cinco amostras de cada UP, totalizando 65 amostras. Utilizou-se a técnica de Reação em Cadeia de Polimerase (PCR) para verificação dos seguintes genes de virulência de Escherichia coli: stx, característico de E. coli enterohemorrágica (EHEC), bfpA, característico de E. coli enteropatogênica (EPEC) e elt e stI, característicos de E. coli enterotoxigênica (ETEC). Os resultados demonstraram que duas amostras de queijadinha e uma amostra do bolo de aipim apresentaram colônias características de coliformes termotolerantes. Desta forma, foram isoladas três cepas para a realização da PCR, no entanto os genes utilizados nas reações não foram identificados nas cepas isoladas. Portanto, sugere-se que as cepas isoladas sejam de patótipos de E. coli com genes de virulência diferentes dos analisados ou de outro membro dos CT, como Enterobacter e Klebsiella. Apesar de não serem confirmados os genes de virulência analisados, a detecção dos CT nos alimentos indica falhas na higiene durante a produção, portanto medidas para controlar e prevenir a contaminação dos produtos devem ser tomadas.


Subject(s)
Humans , Escherichia coli Infections , Enterohemorrhagic Escherichia coli , Virulence/genetics , Brazil , Virulence Factors
13.
Braz. oral res. (Online) ; 35: e062, 2021. tab, graf
Article in English | LILACS, BBO | ID: biblio-1278591

ABSTRACT

Abstract This in vitro study evaluated the impact of TiO2 nanotubes (n-TiO2) incorporated into glass ionomer cement (GIC) on Streptococcus mutans (S. mutans) characteristics at cellular and molecular levels. n-TiO2, synthesized by the alkaline method (20 nm in size), was added to Ketac Molar EasyMix® at 0%, 3%, 5%, and 7% by weight. S. mutans strains were cultured on GIC disks with addition or not of n-TiO2 for 1, 3, and 7 days and the following parameters were assessed: inhibition halo (mm) (n=3/group); cell viability (live/dead) (n=5/group); cell morphology (SEM) (n=3/group); and gene expression by real-time PCR (vicR, covR, gtfB, gtfC, and gtfD) (n=6/group). The data were analyzed by the Kruskal-Wallis test, repeated-measures ANOVA or two-way ANOVA, and Tukey's and Dunn's post-hoc tests (α=0.05). The agar diffusion test showed a higher antibacterial property for 5% n-TiO2 compared with 3% and 7% (p<0.05) with no effect of time (1, 3, and 7 days). The cell number was significantly affected by all n-TiO2 groups, while viability was mostly affected by 3% and 5% n-TiO2, which also affected cell morphology and organization. Real-time PCR demonstrated that n-TiO2 reduced the expression of covR when compared with GIC with no n-TiO2 (p<0.05), with no effect of time, except for 3% n-TiO2 on vicR expression. Within-group and between-group analyses revealed n-TiO2 did not affect mRNA levels of gtfB, gtfC, and gtfD (p>0.05). Incorporation of n-TiO2 at 3% and 5% potentially affected S. mutans viability and the expression of key genes for bacterial survival and growth, improving the anticariogenic properties of GIC.


Subject(s)
Streptococcus mutans , Nanotubes , Titanium , Virulence , Materials Testing , Glass Ionomer Cements/pharmacology
14.
J. appl. oral sci ; 29: e20200733, 2021. graf
Article in English | LILACS | ID: biblio-1154616

ABSTRACT

Abstract Enterococcus faecalis (E. faecalis), one of the main pathogens responsible for refractory periapical periodontitis and nosocomial infections, exhibits markedly higher pathogenicity in biofilms. Objectives Studies have shown that caseinolytic protease P (ClpP) is involved in biofilm formation. However, to date, few studies have investigated the role of ClpP in the survival of E. faecalis, and in enhancing biofilm formation. Therefore, we investigated the role of ClpP in the formation of E. faecalis biofilms. Methodology In our study, we used homologous recombination to construct clpP deleted and clpP complement strains of E. faecalis ATCC 29212. A viable colony counting method was used to analyze the growth patterns of E. faecalis. Crystal violet staining (CV) and confocal scanning laser microscopy (CLSM) were used to characterize biofilm mass formation and scanning electron microscopy (SEM) was used to observe the biofilm microstructure. Data was statistically analyzed via Student's t-test or one-way analysis of variance (ANOVA). Results The results exhibited altered growth patterns for the clpP deletion strains and depleted polysaccharide matrix, resulting in reduced biofilm formation capacity compared to the standard strains. Moreover, ClpP was observed to increase biofilm formation in E. faecalis. Conclusion Our study shows that ClpP can increase biofilm formation in E. faecalis and emphasizes the importance of ClpP as a potential target against E. faecalis.


Subject(s)
Humans , Enterococcus faecalis , Biofilms , Peptide Hydrolases , Virulence , Microscopy, Electron, Scanning , Microscopy, Confocal , Endopeptidase Clp
15.
São José dos Campos; s.n; 2021. 59 p. ilus, graf, tab.
Thesis in Portuguese | LILACS, BBO | ID: biblio-1359953

ABSTRACT

Candida albicans possui capacidade de causar uma ampla variedade de manifestações clínicas devido a múltiplos fatores de virulência que agem simultaneamente para vencer o sistema imune e invadir os tecidos do hospedeiro. Estudos recentes demonstraram que o crescimento de C. albicans pode ser inibido por metabólitos produzidos por Streptococcus mutans, que estão presentes no sobrenadante da cultura bacteriana. Assim, o objetivo desse estudo foi investigar se o sobrenadante da cultura de S. mutans, além de inibir o crescimento de C. albicans, é capaz de atenuar os mecanismos de virulência desse fungo. Inicialmente, uma suspensão padronizada de S. mutans (107 células/mL) foi incubada em caldo BHI a 37ºC por 4 h em 5% de CO2. O crescimento em BHI foi filtrado em membrana de 0,22 µm, obtendo-se o sobrenadante da cultura de S. mutans livre de células. A seguir, uma suspensão padronizada de C. albicans (107 células/mL) foi adicionada ao sobrenadante filtrado da cultura de S. mutans em caldo BHI, sendo incubada a 37ºC por 24 h. Para os grupos controle, a suspensão de C. albicans foi colocada em caldo BHI ou YPD esterilizados e incubada nas mesmas condições. Após o período de incubação, o crescimento de C. albicans foi centrifugado e lavado para obtenção de uma suspensão padronizada de C. albicans contendo as células sobreviventes da exposição ao sobrenadante de S. mutans. Essa suspensão de C. albicans foi então utilizada nos testes in vitro e in vivo para determinação dos fatores de virulência desse micro-organismo. No estudo in vitro, foi investigada a atividade proteolítica extracelular de C. albicans, bem como sua capacidade de filamentação, adesão e formação de biofilmes (1:30, 6, 24 e 48 h). Para o estudo in vivo, foi utilizado o modelo de Galleria mellonella, analisando-se a curva de sobrevivência, o número de células fúngicas e hemócitos na hemolinfa de larvas infectadas por C. albicans. Para a análise estatística foi utilizado ANOVA, teste de Tukey, Kruskal-Wallis e Log-rank, com nível de significância de 5%. Verificou-se que as células de C. albicans expostas ao sobrenadante de S. mutans apresentaram redução na filamentação, formação de biofilmes e patogenicidade em G. mellonella em relação ao controle. A exposição ao sobrenadante de S. mutans também mudou o padrão de aderência de C. albicans. Entretanto, o sobrenadante de S. mutans não reduziu a atividade proteolítica de C. albicans. Concluiu-se que o sobrenadante de S. mutans apresentou capacidade de inibir importantes mecanismos de virulência de C. albicans, podendo ser uma fonte de novos agentes antifúngicos a ser explorada


Candida albicans has the ability to cause a wide variety of clinical manifestations due to multiple virulence factors that act simultaneously to overcome the immune system and invade host tissues. Recent studies have shown that the growth of C. albicans can be inhibited by metabolites produced by Streptococcus mutans. Thus, the objective of this study was to investigate whether the culture supernatant of S. mutans is able to attenuate the virulence mechanisms of this fungus. Initially, a standardized suspension of S. mutans (107 cells/mL) was incubated in BHI broth at 37ºC for 4 h in 5% CO2. The growth in BHI was filtered through a 0.22 µm membrane, obtaining the cell free culture supernatant of S. mutans. Then, a standardized suspension of C. albicans (107 cells/mL) was prepared and added to the supernatant of the culture of S. mutans in BHI broth, being incubated at 37ºC for 24 h. For the control groups, the suspension of C. albicans was placed in sterile BHI or YPD broth and incubated under the same conditions. After the incubation period, the growth of C. albicans was centrifuged and washed to obtain a standardized suspension of C. albicans containing the surviving cells from exposure to the S. mutans supernatant. This suspension of C. albicans was then used to perform in vitro and in vivo tests to determine the virulence factors of this microorganism. In the in vitro study, the extracellular proteolytic activity of C. albicans was investigated, as well as its capacity for filamentation, adhesion and biofilm formation (1:30, 6, 24 and 48 h). For the in vivo study, the Galleria mellonella model was used, analyzing the survival curve, the number of fungal cells and hemocytes in the hemolymph of larvae infected with C. albicans. For statistical analysis, ANOVA, Tukey's test, Kruskal-Wallis and Log-rank were used, with a significance level of 5%. It was found that the cells of C. albicans exposed to the supernatant of S. mutans showed a reduction in filament, formation of biofilms and pathogenicity in G. mellonella in relation to the control. Exposure to the S. mutans supernatant also changed the pattern of adherence of C. albicans. However, the S. mutans supernatant did not reduce the proteolytic activity of C. albicans. It was concluded that the supernatant of S. mutans had the capacity to inhibit important mechanisms of virulence of C. albicans, being able to be a source of new antifungal agents to be explored.


Subject(s)
Animals , Streptococcus mutans , Candida albicans , Virulence Factors , Virulence , Analysis of Variance , Statistics, Nonparametric , Biofilms
16.
Clinics ; 76: e2052, 2021. tab, graf
Article in English | LILACS | ID: biblio-1153974

ABSTRACT

OBJECTIVES: Single nucleotide variants (SNVs) are the most common type of genetic variation among humans. High-throughput sequencing methods have recently characterized millions of SNVs in several thousand individuals from various populations, most of which are benign polymorphisms. Identifying rare disease-causing SNVs remains challenging, and often requires functional in vitro studies. Prioritizing the most likely pathogenic SNVs is of utmost importance, and several computational methods have been developed for this purpose. However, these methods are based on different assumptions, and often produce discordant results. The aim of the present study was to evaluate the performance of 11 widely used pathogenicity prediction tools, which are freely available for identifying known pathogenic SNVs: Fathmn, Mutation Assessor, Protein Analysis Through Evolutionary Relationships (Phanter), Sorting Intolerant From Tolerant (SIFT), Mutation Taster, Polymorphism Phenotyping v2 (Polyphen-2), Align Grantham Variation Grantham Deviation (Align-GVGD), CAAD, Provean, SNPs&GO, and MutPred. METHODS: We analyzed 40 functionally proven pathogenic SNVs in four different genes associated with differences in sex development (DSD): 17β-hydroxysteroid dehydrogenase 3 (HSD17B3), steroidogenic factor 1 (NR5A1), androgen receptor (AR), and luteinizing hormone/chorionic gonadotropin receptor (LHCGR). To evaluate the false discovery rate of each tool, we analyzed 36 frequent (MAF>0.01) benign SNVs found in the same four DSD genes. The quality of the predictions was analyzed using six parameters: accuracy, precision, negative predictive value (NPV), sensitivity, specificity, and Matthews correlation coefficient (MCC). Overall performance was assessed using a receiver operating characteristic (ROC) curve. RESULTS: Our study found that none of the tools were 100% precise in identifying pathogenic SNVs. The highest specificity, precision, and accuracy were observed for Mutation Assessor, MutPred, SNP, and GO. They also presented the best statistical results based on the ROC curve statistical analysis. Of the 11 tools evaluated, 6 (Mutation Assessor, Phanter, SIFT, Mutation Taster, Polyphen-2, and CAAD) exhibited sensitivity >0.90, but they exhibited lower specificity (0.42-0.67). Performance, based on MCC, ranged from poor (Fathmn=0.04) to reasonably good (MutPred=0.66). CONCLUSION: Computational algorithms are important tools for SNV analysis, but their correlation with functional studies not consistent. In the present analysis, the best performing tools (based on accuracy, precision, and specificity) were Mutation Assessor, MutPred, and SNPs&GO, which presented the best concordance with functional studies.


Subject(s)
Humans , Computational Biology , Mutation, Missense/genetics , Virulence , Polymorphism, Single Nucleotide , Sexual Development , Mutation
17.
Braz. j. biol ; 81(2): 424-436, 2021. tab, ilus
Article in English | LILACS, VETINDEX | ID: biblio-1153346

ABSTRACT

Pathogenic Yersinia enterocolitica (Y. enterocolitica) is one of the food-borne entero-pathogen responsible for yersiniosis in humans. The purpose of this research was to survey the prevalence, virulence-associated genes, and antimicrobial resistance of Y. enterocolitica isolated from meat and meat product samples in Egypt. Forty-one (5.9%) out of 700- samples of chicken meat, beef, ground beef, and sausage were positive Y. enterocolitica with a high prevalence in chicken meat (12%). Five virulence genes (ail, inv, ystA, ystB, and yadA) were characterized among 41 Y. enterocolitica isolates with variable frequencies. Among the strains tested, the ystB gene was detected with a high percentage (78.1%), followed by inv gene (70.7%), ail gene (14.6%), ystA gene (12.2%), and yadA gene (2.4%). A high resistance rate was estimated to amoxicillin-clavulanic acid (100%), followed by cefazolin (95%), ampicillin (65.9%), and doxycycline (51.2%), whilst a high sensitivity rate was observed to gentamicin and ciprofloxacin (97.6% each). Interestingly, the multidrug resistance was specified in the 70.7% of strains and showing 13 resistance patterns. Based on nucleotide sequence analysis of the 16s rRNA gene, the phylogenetic tree showed the genetic relatedness amongst Y. enterocolitica isolates. These findings highlighted the emergence of virulent and multidrug-resistant pathogenic Y. entrocolitica in retailed meat and meat products in Egypt.


A Yersinia enterocolitica patogênica (Y. enterocolitica) é um dos enteropatógenos de origem alimentar responsáveis pela yersiniose no ser humano. O objetivo desta pesquisa foi avaliar a prevalência, genes associados à virulência e resistência antimicrobiana de Y. enterocolitica isolada de amostras de carne e produtos à base de carne no Egito. Quarenta e um (5,9%) de 700 amostras de carne de frango, carne bovina, moída e linguiça foram Y. enterocolitica positivas, com alta prevalência em carne de frango (12%). Cinco genes de virulência (ail, inv, ystA, ystB e yadA) foram caracterizados entre 41 isolados de Y. enterocolitica com frequências variáveis. Entre as cepas testadas, o gene ystB foi detectado com uma alta porcentagem (78,1%), seguido pelo gene inv (70,7%), ail genes (14,6%), gene ystA (12,2%) e gene yadA (2,4%). Foi estimada uma alta taxa de resistência ao ácido amoxicilina-clavulânico (100%), seguida de cefazolina (95%), ampicilina (65,9%) e doxiciclina (51,2%), enquanto uma alta taxa de sensibilidade foi observada para gentamicina e ciprofloxacina (97,6% cada). Curiosamente, a resistência a múltiplas drogas foi especificada em 70,7% das cepas e mostrando 13 padrões de resistência. Com base na análise da sequência nucleotídica do gene rRNA 16s, a árvore filogenética mostrou a relação genética entre isolados de Y. enterocolitica. Esses achados destacaram o surgimento de Y. entrocolitica patogênica virulenta e multirresistente em carnes e produtos à base de carne no Egito.


Subject(s)
Humans , Yersinia enterocolitica/genetics , Drug Resistance, Bacterial/genetics , Meat/microbiology , Meat Products/microbiology , Phylogeny , Virulence/genetics , RNA, Ribosomal, 16S , Egypt , Genotype , Anti-Bacterial Agents/pharmacology
18.
Article in English | LILACS, VETINDEX | ID: biblio-1363092

ABSTRACT

Fifty-two Staphylococcus aureus recovered from papillary ostium and milk samples collected from cows with subclinical mastitis and milking environments in three small dairy herds located in southeastern Brazil were subjected to PCR identification based on the thermonuclease (nuc) gene. All the strains were submitted to in vitro antimicrobial susceptibility testing, and we investigated the sequence types (STs), agr groups (I-IV), virulence genes encoding for Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), biofilm-associated proteins, bi-component toxins, pyrogenic toxin superantigens, and enterotoxins. Screening for oxacillin resistance (2-6 µg/ml oxacillin), beta-lactamase activity assays, and PCR for the mecA/mecC genes detected 26 methicillin-susceptible S. aureus(MSSA) and 26 mec-independent oxacillin-nonsusceptible S. aureus (MIONSA). While MSSA isolates were found to be susceptible to all antimicrobial agents tested, or only resistant to penicillin and ampicillin, MIONSA isolates were multidrug-resistant. ST126-agr group II MSSA isolates were prevalent in milk (n=14) and carried a broad set of virulence genes (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla, and hlb), as well as the ST126-agr group II MIONSA isolated from milking liners (n=1), which also carried the eta gene. ST1-agr group III MIONSA isolates (n=4) were found in papillary ostium and milk, but most MIONSA isolates (n=21), which were identified in both papillary ostium and milking liners, were agr-negative and assigned to ST126. The agr-negative and agr group III lineages showed a low potential for virulence. Studies on the characterization of bovine-associated MSSA/MIONSA are essential to reduce S. aureus mastitis to prevent economic losses in dairy production and also to monitor the zoonotic potential of these pathogens associated with invasive infections and treatment failures in healthcare.


Cinquenta e dois isolados de Staphylococcus aureus obtidos de amostras colhidas do óstio papilar, do leite de vacas com mastite subclínica e do ambiente de ordenha em três fazendas de rebanhos leiteiros localizadas no sudeste do Brasil foram identificados por PCR para o gene da termonuclease (nuc). Todos os isolados foram testados para sensibilidade a antimicrobianos e foram investigados os sequence types (STs), grupos agr (I-IV) e genes de virulência que codificam Microbial Surface Components Recognizing Adhesive Matrix Molecules (MSCRAMMs), proteínas associadas a biofilme, toxinas bi-componentes, toxinas pirogênicas com propriedades de superantígenos e enterotoxinas. Triagem para detecção de resistência à oxacilina (2-6 µg/ml oxacilina), ensaios de atividade de enzimas beta-lactamases e PCR para os genes mecA/mecC detectaram 26 estirpes de S. aureus sensíveis à meticilina (methicillin-susceptible S. aureus, MSSA) e 26 estirpes de S. aureus mec-negativas não sensíveis à meticilina (mec-independent oxacillin-nonsusceptible S. aureus, MIONSA). Enquanto os isolados MSSA foram sensíveis a todos os agentes antimicrobianos testados, ou apenas resistentes à penicilina e ampicilina, os isolados MIONSA foram multirresistentes. MSSA ST126-agr grupo II foram prevalentes no leite (n= 14) e apresentaram um amplo conjunto de genes de virulência (clfA, clfB, eno, fnbA, fiB, icaA, icaD, lukED, hla e hlb), assim como o isolado MIONSA ST126-agr grupo II proveniente de um insuflador (n= 1), o qual também apresentou o gene eta. MIONSA ST1-agr grupo III (n= 4) foram identificados no óstio papilar e leite, mas a maioria dos isolados MIONSA (n= 21), encontrados em óstios papilares e insufladores, foram agr-negativos e pertenceram ao ST126. As linhagens agr-negativas e agr grupo III apresentaram baixo potencial de virulência. Estudos sobre a caracterização de MSSA/MIONSA associados a bovinos são essenciais para a redução da mastite causada por S. aureus e de perdas econômicas na produção leiteira e, também, para o monitoramento do potencial zoonótico desses patógenos associados a infecções invasivas e falhas de tratamento em ambientes hospitalares.


Subject(s)
Animals , Female , Cattle , Staphylococcus aureus/isolation & purification , Mastitis, Bovine/microbiology , Anti-Bacterial Agents/pharmacology , Staphylococcus aureus/drug effects , Staphylococcus aureus/genetics , Virulence , Microbial Sensitivity Tests , Polymerase Chain Reaction
19.
Chinese Journal of Biotechnology ; (12): 4056-4065, 2021.
Article in Chinese | WPRIM | ID: wpr-921486

ABSTRACT

Photorhabdus is a Gram-negative bacterium from the family Enterobacteriaceae that lives in a symbiotic association with nematode or insects. In addition to the role of being insect pathogens, one species called Photorhabdus asymbiotica (Pa) causes human infection around the world. Nevertheless, how does this transkingdom infection occur remains elusive. Here we focus on one pathogenic determinant called Photorhabdus virulence cassette (PVC) that is founded in the Pa genome and many other pathogens. The RNA-seq and qPCR data showed that the NF-κB and MAPK pathways were drastically activated in the PVC-treated mammalian macrophages. Western blotting assays using samples treated with various inhibitors of the affected pathways confirmed the results we have observed for MAPK pathway previously. p65 translocation assays validated the NF-κB activation in the macrophages after PVC treatment. Moreover, the bacterial phagocytosis by macrophage was also promoted by PVC at the early stage, and this phagocytosis was inhibited by cytoskeleton inhibitors. Thus, the results indicated that PVC is involved in the bacterial invasion by activating NF-κB and MAPK signaling pathway, providing a new perspective for analyzing the pathogenicity of Pa in human infections.


Subject(s)
Animals , Humans , Macrophages , NF-kappa B/genetics , Photorhabdus , Signal Transduction , Virulence
20.
Article in English | WPRIM | ID: wpr-888501

ABSTRACT

To investigate the relationship of biofilm-forming ability of (PA) with swimming motility, twitching motility and virulence gene distribution. A total of 192 clinical isolates of PA were collected consecutively. Microtiter plate method was used to evaluate the ability to form biofilm. The swimming and twitching motilities were detected by plate method. Polymerase chain reaction (PCR) was used to detect virulence genes. Of the 192 PA clinical isolates, 186 (96.9%) showed biofilm-forming ability. Among them, 36 isolates showed weak biofilm-forming ability, 84 exhibited moderate biofilm-forming ability and 66 showed strong biofilm-forming ability. The diameters of the swimming ring for PA with none biofilm-forming ability, weak biofilm-forming ability, moderate biofilm-forming ability, strong biofilm-forming ability were (9.12±6.76), (18.42±7.51), (19.10±4.77) and respectively. The diameters of the twitching ring for PA in above groups were (8.38±1.50), (17.21±7.42), (18.49±5.62) and respectively. The swimming motility and twitching motility of none biofilm-forming ability group were weaker than biofilm-forming ability groups (all <0.05). Among 192 PA strains, 163 were positive (84.9%), 40 were positive (20.8%), 183 were positive (95.3%), and 189 were positive (98.4%). The positive rate of PA virulence gene , and were different in strains with different biofilm-forming abilities (<0.05). The rate of in the strong biofilm-forming ability group was lower than that in the moderate biofilm-forming ability group (=9.293, <0.01) and the weak biofilm-forming ability group (=9.997, <0.01). The rate of in the strong biofilm-forming ability group was higher than that in the weak biofilm-forming ability group (=10.803, <0.01). Most clinical isolates of PA can form biofilm. Swimming and twitching motilities are related to the formation of biofilm, but not significantly related to strength of biofilm-forming ability. The virulence genes of type Ⅲ secretion system for PA may be related to the biofilm-forming ability.


Subject(s)
Biofilms , Humans , Swimming , Virulence/genetics
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