Comparative Study of Staphylococcus epidermidis Virulence Profiles in an animal Model of Endophthalmitis

Introduction: Gram-positive staphylococci are responsible for over 90% of cases of postoperative infectious endophthalmitis, with Staphylococcus epidermidis accounting for approximately 70% of isolated microorganisms. Objective: To evaluate the relationship between S. epidermidis virulence and severity of endophthalmitis in an animal model. Methodology: New Zealand albino rabbits were divided into two groups and administered 100 colony-forming units of S. epidermidis strains. In the virulent group, four rabbits received a multi-antibiotic resistant, mecA, ica, and atlE gene carrying S. epidermidis strain, from a patient´s conjuntival microbiota and three a biofilm-forming S. epidermidis ATCC 35984. In the non-virulent group, five rabbits were inoculated with a strain sensitive to all tested antibiotics and lacking mecA, ica, and atlE genes, also from a patient and three rabbits received the non-producer biofilm S. epidermidis ATCC 29122. Clinical and ultrasound examinations were conducted every three hours until endophthalmitis symptoms appeared, followed by daily clinical assessments. Histological evaluations were performed 15 days post-inoculation. Results: The less virulent group displayed milder inflammation and reduced intraocular damage in comparison to the more virulent group based on clinical and ultrasound observations. Nevertheless, histopathological analysis revealed similar inflammation in all groups, 15 days post-inoculation. Discussion: Less virulent S. epidermidis strains induced less severe inflammation as observed through clinical and ultrasound assessments. However, long-term histopathological assessments showed effects comparable to those seen with the more virulent strain.

Introducción: Gram-positive staphylococci are responsible for over 90% of cases of postoperative infectious endophthalmitis, with Staphylococcus epidermidis accounting for approximately 70% of isolated microorganisms. Objetivo: Evualuar la relación entre la virulencia de S. epidermidis y la gravedad de la endoftalmitis en un modelo animal. Metodología: Se dividieron conejos albinos de Nueva Zelanda en dos grupos y se les administraron 100 unidades formadoras de colonias de cepas de S. epidermidis. En el grupo virulento, cuatro conejos recibieron una cepa multirresistente de S. epidermidis portadora de gen mecA, ica y atlE, de la microbiota conjuntival de un paciente y tres conejos la cepa S. epidermidis ATCC 35984 formadora de biopelículas. En el grupo no-virulento, se inocularon cinco conejos con una cepa sensible a todos los antibióticos probados y que carecía de los genes mecA, ica y atlE, también de un paciente y tres conejos recibieron la cepa S. epidermidis ATCC 29122 no productora de biopelícula. Se realizaron exámenes clínicos y ecográficos cada tres horas hasta la aparición de síntomas de endoftalmitis, seguido de evaluaciones clínicas diarias. Las evaluaciones histológicas se realizaron 15 días después de la inoculación. Resultados: El grupo menos virulento mostró una inflamación más leve y un daño intraocular reducido en comparación con el grupo más virulento según observaciones clínicas y ecográficas. Sin embargo, el análisis histopatológico reveló una inflamación similar en todos los grupos, 15 días después de la inoculación. Discusión: Las cepas de S. epidermidis menos virulentas indujeron una inflamación menos grave, como se observó mediante evaluaciones clínicas y ecográficas. Sin embargo, las evaluaciones histopatológicas a largo plazo mostraron efectos comparables a los observados con la cepa más virulenta.

Evolving SARS-CoV-2 severity among hospital and university affiliates in Spain and Greater Boston.

INTRODUCTION: The COVID-19 pandemic caused by the SARS-CoV-2 virus greatly affected healthcare workers and healthcare systems. It also challenged schools and universities worldwide negatively affecting in-person education. We conducted this study is to assess the evolution of SARs-CoV-2 virulence over the course of the pandemic. METHODS: A combined cohort of University students in Spain and HCWs from the two hospitals in Spain, and one healthcare system in the Greater Boston area was followed prospectively from March 8th, 2020, to January 31st, 2022 for diagnosis with COVID-19 by PCR testing and related sequelae. Follow-up time was divided into four periods according to distinct waves of infection during the pandemic. Severity of COVID-19 was measured by case-hospitalization rate. Descriptive statistics and multivariable-adjusted statistics using the Poisson mixed-effects regression model were applied. As a sensitivity analysis, information on SARS-CoV-2 RNA in wastewater and COVID-19 deaths through May 30, 2023 from the Boston area was collected. RESULTS: For the last two periods of the study (January 1st to December 15th, 2021 and December 16th, 2021 to January 31st, 2022) and relative to the first period (March 8th to May 31st, 2020), the incidence rate ratios (IRRs) of hospitalization were 0.08 (95% CI, 0.03-0.17) and 0.03 (95% CI, 0.01-0.15), respectively. In addition, a relative risk 0.012 CI95% (0.012-0.012) was observed when comparing COVID-19 mortality versus SARS-CoV-2 RNA copies/mL in Boston-area wastewater over the period (16th December 2021 to 30th May 2023) and relative to the first period. CONCLUSIONS: The severity of COVID-19 and immunity of our populations evolved over time, resulting in a decrease in case severity. We found the case-hospitalization rate decreased more than 90% in our cohort despite an increase in incidence.

Molecular characterization of Aeromonas hydrophila isolates from diseased fishes in district Kasur, Punjab, Pakistan

Abstract Pakistan is an agricultural country and fisheries play a very important role in the economic development of the country. Different diseases are prevalent in Pakistani fish but information related to the causative agents is not well-known. Keeping in view the significance of bacterial pathogens as the causative agents of multiple fish diseases, the present study was conducted for identification, characterization and analysis of virulence genes of Aeromonas spp. isolated from diseased fishes. A total of fifty fish samples having multiple clinical indications were collected from different fish farms of district Kasur, Punjab Pakistan. For isolation of Aeromonas spp. samples were enriched and inoculated on Aeromonas isolation medium. Isolates were identified and characterized by different biochemical tests, Analytical Profile Index (API) 20E kit and Polymerase Chain Reaction (PCR) assays. All isolates were screened for three putative virulence genes including aerolysin (aer), haemolysin (hyl) and heat labile cytotonic enterotoxin (alt). Seven isolates of Aeromonas (A.) hydrophila were retrieved and identified based on API 20E. These isolates were further confirmed as A. hydrophila on the basis of PCR assays. Three isolates were detected positive for the presence of virulence genes (alt and hyl). Whereas aerolysin (aer) gene was not present in any of A. hydrophila isolates. The present study confirmed A. hydrophila as the causative agent of epizootic ulcerative syndrome and motile Aeromonas septicemia in fish farms of district Kasur, Punjab Pakistan. Moreover, detection of two virulence genes (alt and hyl) in A. hydrophila isolates is a threat for fish consumers of study area.

Resumo O Paquistão é um país agrícola, onde a pesca desempenha um papel muito importante para o desenvolvimento econômico. Diferentes doenças são prevalentes em peixes do Paquistão, mas as informações relacionadas aos agentes causadores não são bem conhecidas. Tendo em vista a importância dos patógenos bacterianos como agentes causadores de múltiplas doenças em peixes, o presente estudo foi conduzido para identificação, caracterização e análise de genes de virulência de isolados de Aeromonas spp. de peixes doentes. Foram coletadas 50 amostras de peixes com múltiplas indicações clínicas em diferentes fazendas do distrito de Kasur, Punjab, Paquistão. Para isolar Aeromonas spp., as amostras foram enriquecidas e inoculadas em meio de isolamento. Os isolados foram identificados e caracterizados por diferentes testes bioquímicos, kit Analytical Profile Index (API) 20E, e ensaios de reação em cadeia da polimerase (PCR). Todos os isolados foram selecionados para três genes de virulência putativos, incluindo aerolisina (aer), hemolisina (hyl) e enterotoxina citotônica termolábil (alt). Sete isolados de Aeromonas hydrophila foram recuperados e identificados com base no API 20E. Esses isolados foram posteriormente confirmados como A. hydrophila de acordo com ensaios de PCR. Três isolados indicaram a presença de genes de virulência (alt e hyl), enquanto o gene aerolisina (aer) não esteve presente em nenhum dos isolados de A. hydrophila. O presente estudo confirmou A. hydrophila como o agente causador da síndrome ulcerativa epizoótica e septicemia móvel por Aeromonas em fazendas de peixes, no distrito de Kasur, Punjab, Paquistão. Além disso, a detecção de dois genes de virulência (alt e hyl) em isolados de A. hydrophila é uma ameaça para os consumidores de peixes da área de estudo.

Molecular characterization of Aeromonas hydrophila isolates from diseased fishes in district Kasur, Punjab, Pakistan / Caracterização molecular de isolados de Aeromonas hydrophila de peixes doentes no distrito de Kasur, Punjab, Paquistão

Abstract Pakistan is an agricultural country and fisheries play a very important role in the economic development of the country. Different diseases are prevalent in Pakistani fish but information related to the causative agents is not well-known. Keeping in view the significance of bacterial pathogens as the causative agents of multiple fish diseases, the present study was conducted for identification, characterization and analysis of virulence genes of Aeromonas spp. isolated from diseased fishes. A total of fifty fish samples having multiple clinical indications were collected from different fish farms of district Kasur, Punjab Pakistan. For isolation of Aeromonas spp. samples were enriched and inoculated on Aeromonas isolation medium. Isolates were identified and characterized by different biochemical tests, Analytical Profile Index (API) 20E kit and Polymerase Chain Reaction (PCR) assays. All isolates were screened for three putative virulence genes including aerolysin (aer), haemolysin (hyl) and heat labile cytotonic enterotoxin (alt). Seven isolates of Aeromonas (A.) hydrophila were retrieved and identified based on API 20E. These isolates were further confirmed as A. hydrophila on the basis of PCR assays. Three isolates were detected positive for the presence of virulence genes (alt and hyl). Whereas aerolysin (aer) gene was not present in any of A. hydrophila isolates. The present study confirmed A. hydrophila as the causative agent of epizootic ulcerative syndrome and motile Aeromonas septicemia in fish farms of district Kasur, Punjab Pakistan. Moreover, detection of two virulence genes (alt and hyl) in A. hydrophila isolates is a threat for fish consumers of study area.

Resumo O Paquistão é um país agrícola, onde a pesca desempenha um papel muito importante para o desenvolvimento econômico. Diferentes doenças são prevalentes em peixes do Paquistão, mas as informações relacionadas aos agentes causadores não são bem conhecidas. Tendo em vista a importância dos patógenos bacterianos como agentes causadores de múltiplas doenças em peixes, o presente estudo foi conduzido para identificação, caracterização e análise de genes de virulência de isolados de Aeromonas spp. de peixes doentes. Foram coletadas 50 amostras de peixes com múltiplas indicações clínicas em diferentes fazendas do distrito de Kasur, Punjab, Paquistão. Para isolar Aeromonas spp., as amostras foram enriquecidas e inoculadas em meio de isolamento. Os isolados foram identificados e caracterizados por diferentes testes bioquímicos, kit Analytical Profile Index (API) 20E, e ensaios de reação em cadeia da polimerase (PCR). Todos os isolados foram selecionados para três genes de virulência putativos, incluindo aerolisina (aer), hemolisina (hyl) e enterotoxina citotônica termolábil (alt). Sete isolados de Aeromonas hydrophila foram recuperados e identificados com base no API 20E. Esses isolados foram posteriormente confirmados como A. hydrophila de acordo com ensaios de PCR. Três isolados indicaram a presença de genes de virulência (alt e hyl), enquanto o gene aerolisina (aer) não esteve presente em nenhum dos isolados de A. hydrophila. O presente estudo confirmou A. hydrophila como o agente causador da síndrome ulcerativa epizoótica e septicemia móvel por Aeromonas em fazendas de peixes, no distrito de Kasur, Punjab, Paquistão. Além disso, a detecção de dois genes de virulência (alt e hyl) em isolados de A. hydrophila é uma ameaça para os consumidores de peixes da área de estudo.

Diminuição da expressão do microRNA-629 em amostras de câncer gástrico potencializada pelo marcador de virulências do H. pylori, gene cagA / Decreased expression of microrna-629 in gastric cancer samples potentiated by the virulence marker of h. pylori, caga gene

ABSTRACT Background: Helicobacter pylori (H. pylori) is a gram-negative bacterium associated with the etiology of several gastrointestinal tract pathologies, and cagA-positive (cagA+) strains are found in populations with gastric ulcers and precancerous lesions, inducing pro-inflammatory responses. The development of neoplasms is related to microRNA (miRNA) dysregulation, indicating highly expressed miRNA-629. The article aims to correlate the expression level of miRNA-629 with the presence of H. pylori and the pathogenicity marker cagA. Methods: 203 gastric biopsy samples were evaluated from individuals with normal gastric tissue (n=60), gastritis (n=96), and gastric cancer (n=47) of both genders and over 18 years old. The samples were subdivided according to the presence or absence of H. pylori, detected by polymerase chain reaction (PCR). RNA was extracted using a commercial kit and quantified. Complementary DNA (cDNA) was synthesized using commercial kits, and the relative expression was calculated using the 2-ΔΔCt method. Results: Individuals infected with H. pylori are nine times more likely to develop gastric cancer. Cancer patients appeared to have decreased expression of miRNA-629; however, the presence of the bacterium would not influence this reduction. Individuals in the cancer group showed lower miRNA-629 expression when cagA+; however, in the control group, the expression was higher when cagA+. Conclusion: H. pylori is a factor involved in the etiology and progression of gastric diseases. Reduction in miRNA-629 expression in cancer patients occurs independent of the presence of the bacterium, but when the cagA pathogenicity marker is present, it induces changes in the gene expression of the respective miRNA.

RESUMO Contexto: Helicobacter pylori (H. pylori) é uma bactéria gram-negativa associada à etiologia de várias patologias do trato gastrointestinal, e cepas positivas para cagA (cagA+) são encontradas em populações com úlceras gástricas e lesões pré-cancerígenas, induzindo respostas pró-inflamatórias. O desenvolvimento de neoplasias está relacionado à desregulação do microRNA (miRNA), indicando miRNA-629 altamente expresso. O artigo tem como objetivo correlacionar o nível de expressão do miRNA-629 com a presença de H. pylori e o marcador de patogenicidade cagA. Métodos: Foram avaliadas 203 amostras de biópsia gástrica de indivíduos com tecido gástrico normal (n=60), gastrite (n=96) e câncer gástrico (n=47) de ambos os sexos e com mais de 18 anos. As amostras foram subdivididas de acordo com a presença ou ausência de H. pylori, detectado por reação em cadeia da polimerase (PCR). O RNA foi extraído usando um kit comercial e quantificado. O DNA complementar (cDNA) foi sintetizado usando kits comerciais, e a expressão relativa foi calculada usando o método 2-ΔΔCt. Resultados: Indivíduos infectados com H. pylori têm nove vezes mais chances de desenvolver câncer gástrico. Pacientes com câncer parecem ter diminuição da expressão do miRNA-629; no entanto, a presença da bactéria não influenciaria essa redução. Indivíduos no grupo do câncer apresentaram menor expressão do miRNA-629 quando cagA+; no entanto, no grupo controle, a expressão foi maior quando cagA+. Conclusão: H. pylori é um fator envolvido na etiologia e progressão das doenças gástricas. A redução na expressão do miRNA-629 em pacientes com câncer ocorre independentemente da presença da bactéria, mas quando o marcador de patogenicidade cagA está presente, induz mudanças na expressão gênica do respectivo miRNA.

Interação de cepas de Lactobacillus crispatus com Streptococcus agalactiae em culturas celulares mimetizando o ambiente vaginal / Interaction between Lactobacillus crispatus and Streptococcus agalactiae strains in cell cultures mimicking the vaginal environment

A microbiota vaginal é dominada pelo gênero Lactobacillus, mantendo um pH ácido crucial para a saúde. Alterações hormonais e a menopausa podem impactar essa microbiota. Estreptococos do Grupo B (EGB) são associados a infecções neonatais e podem colonizar a microbiota vaginal. A interação entre Lactobacillus e EGB é complexa, com resultados conflitantes em estudos in vitro e in vivo. O uso de probióticos contendo Lactobacillus pode ter benefícios, como alterar a positividade para EGB em um grupo que recebeu o tratamento. Contudo a replicabilidade deste resultado é limitada, e os mecanismos envolvidos nessa interação ainda são pouco elucidados. Portanto o objetivo desse estudo foi caracterizar cepas de EGB, avaliar sua interação com L. crispatus em diversas condições. Neste estudo foram selecionadas seis cepas, pertencentes aos sorotipos Ia, II, III e V. Essas cepas foram caracterizadas de acordo com o sorotipo capsular, presença de genes de virulência (hialuronidase, ß-citolisina/hemolisina, e ilhas de pili 1, 2a e 2b), resistência a antimicrobianos (penicilina, cefepima, vancomicina, eritromicina e clindamicina), curva de crescimento, Restriction Fragment Length Polymorphism (RFLP) e Multi-Locus Sequence Typing (MLST). O resultado de MLST identificou os sequence types ST1, ST23 ST28 e ST182, e os clonal complexes CC1, CC19 e CC23. Cepas possuem a maior parte dos genes de virulência testados. Somente uma cepa apresentou alguma resistência, no caso à eritromicina e clindamicina. Resultados que estão de acordo com a literatura como os principais descritos em isolados clínicos. Os ensaios de interação realizados foram: crescimento em co-cultura, formação de biofilme, ensaios de adesão e exclusão em cultura celular e por fim, análise do perfil proteico. Alguns efeitos de L. crispatus no EGB observados foram aumento na formação de biofilme de EGB e diminuição da sua proliferação quando em co-cultura. Contudo esses resultados variaram de acordo com a cepa de EGB. Nos ensaios de competição em cultura celular, a presença de L. crispatus levou à diminuição da adesão em uma cepa pertencente ao sorotipo III, e aumento de adesão em uma cepa pertencente ao sorotipo V. Quando a cultura de células recebeu tratamento prévio de L. crispatus, nos ensaios de exclusão, houve menor adesão de EGB. Contudo todos os efeitos observados são cepa-dependente; não foram encontradas associações entre o comportamento das cepas e seu sorotipo capsular ou fenótipo MLST. Estudos futuros podem elucidar as respostas ativadas na presença de microrganismos comensais

The vaginal microbiota is dominated by the genus Lactobacillus, which helps to maintain a crucial acidic pH for health. Hormonal changes and menopause can impact this microbiota. Group B Streptococcus (GBS) are associated with neonatal infections and can colonize the vaginal microbiota. The interaction between Lactobacillus and GBS is complex, with conflicting results in in vitro and in vivo studies. The use of probiotics containing Lactobacillus may have benefits, such as altering GBS positivity in a treated group. However, the replicability of this result is limited, and the mechanisms involved in this interaction are still poorly understood. The use of probiotics containing Lactobacillus may have some benefits, but further research is needed. These strains were characterized based on capsular serotype, presence of virulence genes (hyaluronidase, ß-cytolysin/hemolysin, and pili islands 1, 2a, and 2b), antimicrobial resistance (penicillin, cefepime, vancomycin, erythromycin, and clindamycin), growth curve, Restriction Fragment Length Polymorphism (RFLP), and Multi-Locus Sequence Typing (MLST) Therefore, the aim of this study was to characterize GBS strains, evaluate their interaction with L. crispatus under various conditions. Six strains were selected for this study, belonging to serotypes Ia, II, III, and V. MLST results identified sequence types ST1, ST23, ST28, and ST182, and clonal complexes CC1, CC19, and CC23. Most strains possessed the tested virulence genes, with only one strain showing resistance to erythromycin and clindamycin. These results are in line with the literature. Interaction assays included co-culture growth, biofilm formation, adhesion and exclusion assays in cell culture, and, finally, protein profile analysis. Some observed effects of L. crispatus on GBS included an increase in GBS biofilm formation and a decrease in GBS proliferation during co-culture. However, these results varied according to the GBS strain. GBS interaction with L. crispatus resulted in increased biofilm formation and decreased proliferation in co-culture. In cell culture competition assays, the presence of L. crispatus led to decreased adhesion in one GBS strain belonging to serotype III and increased adhesion in one strain belonging to serotype V. When cell culture received pre-treatment with L. crispatus, exclusion assays showed lower GBS adhesion. However, all observed effects are strain-dependent; no associations were found between strain behavior and capsular serotype or MLST phenotype. Future studies may elucidate the responses activated in the presence of commensal microorganisms

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

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

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

Murciélagos como vectores de enfermedades virales e impacto en la salud humana

Introducción: Los murciélagos se destacan por ser los únicos mamíferos voladores, con alrededor de 1 400 especies que cumplen un rol fundamental como controladores de plagas y polinizadores de plantas nocturnas. Sin embargo, su influencia sobre la salud humana se ha evidenciado cada vez más, en particular después del surgimiento de brotes epidémicos de enfermedades virales asociadas a estos mamíferos. Objetivo: Analizar la influencia de los murciélagos en la salud humana, centrándose en su papel como portadores de enfermedades virales y su potencial como reservorios y vectores de enfermedades. Métodos: Se realizó una revisión bibliográfica de la literatura utilizando descriptores MeSH y términos como: Animals, Wild Chiroptera, Virus Diseases, Zoonoses, Disease Vectors, Disease Reservoirs, Public Health, bats, Communicable Disease Control, Disease Outbreaks, Prevention and Control. Se revisaron 1 442 artículos en bases de datos y documentos oficiales, se seleccionaron las fuentes relevantes con Mendeley Desktop 1.19.4. y se obtuvieron al final 47 artículos. Resultados: Existen varias especies de murciélagos que pueden afectar la salud del ser humano y que albergan en especial virus de las familias Filoviridae, Coronaviridae y Paramixoviridae. Los murciélagos se consideran incubadoras óptimas para la propagación de virus debido a su sistema inmune único que lo hace resistente a estos agentes infecciosos. Conclusiones: La vigilancia y monitoreo de los murciélagos, junto con acciones de educación pública y una gestión adecuada de sus hábitats, son fundamentales para la detección temprana y prevención de la transmisión de nuevos virus de estos mamíferos a los humanos.

Introduction: Bats are the only flight mammals, with around 1,400 species playing critical roles as pest controllers and nocturnal plant pollinators. However, its impact on human health has become increasingly evident, especially after the appearance of epidemic outbreaks of viral diseases related to these mammals. Objetive: To analyze the influence of bats on human health, focusing on their role as carriers of viral diseases and their potential as reservoirs and vectors of diseases. Methods: A literature bibliographical review was conducted using MeSH descriptors and keywords such as: Animals, Wild Chiroptera, Virus Diseases, Zoonosis, Disease Vectors, Disease Reservoirs, Public Health, bats, Communicable Disease Control, Disease Outbreaks, Prevention and Control. 1442 articles in databases and official documents were reviewed, selecting the relevant sources with Mendeley Desktop 1.19.4., obtaining 47 articles at the end. Results: There are several species of bats that can affect human health and that mainly harbor viruses from the Filoviridae families, Coronaviridae and Paramyxoviridae. Bats are considered optimal incubators for the spread of the virus due to their unique immune system that makes them particularly resistant to these infectious agents. Conclusions: Surveillance and monitoring of bats, together with public education actions and proper management of their habitats, are essential for early detection and prevention of transmission of new viruses from these mammals to humans.

Evolución de la virulencia de SARS-CoV-2 en Chile / Evolution of the virulence of SARS CoV-2 in Chile

INTRODUCCIÓN: La evolución de la virulencia ha despertado el interés de la biología evolutiva por décadas. Se trata de co-evolución entre agentes patógenos y sus hospederos. Se han planteado diferentes hipótesis para la evolución de la virulencia, entre ellas la evolución con un compromiso virulencia-transmisión. OBJETIVO: Estudiar la evolución de la letalidad y la transmisión del SARS CoV-2 en Chile, con la hipótesis que ha existido un compromiso con disminución de la letalidad y aumento de la transmisión de esta durante la epidemia. RESULTADOS: La letalidad diaria en Chile disminuyó claramente. Aunque no se encontró correlación entre la letalidad diaria y el número reproductivo efectivo, el número reproductivo efectivo máximo asociado a cada variante viral, presentó un aumento claro desde la aparición de la variante γ en adelante (δ y O) en Chile. CONCLUSIÓN: Este estudio muestra una evolución de la virulencia con un compromiso virulenciatransmisión. Esto puede ser explicado en gran parte por la evolución viral, pero el cambio en letalidad también puede ser afectado por las intervenciones no farmacológicas y farmacológicas realizadas por la población humana.

BACKGROUND: The evolution of virulence has aroused the interest of evolutionary biology for decades. It is about co-evolution between pathogens and their hosts. Different hypotheses have been put forward for the evolution of virulence, including evolution with a virulence-transmission trade-off. AIM: To study the evolution of the fatality rate and transmission of SARS CoV-2 in Chile, with the hypothesis that there has been a trade-off to a decrease in lethality and an increase in its transmission during the epidemic. RESULTS: The daily fatality rate in Chile clearly decreased. Although no correlation was found between daily fatality rate and effective reproductive number, the maximum effective reproductive number associated with each viral variant showed a clear increase from the appearance of the γ variant onwards (δ and O) in Chile. CONCLUSION: This study shows an evolution of virulence with a virulence-transmission trade-off. This can be largely explained by viral evolution, but the change in lethality can also be affected by non-pharmacological and pharmacological interventions carried out by the human population.

Bacteremia by non-O1/non-O139 Vibrio cholerae: Case description and literature review / Bacteriemia por Vibrio cholerae no-O1/no-O139: descripción de un caso y revisión de la literatura

Bacteremia by non-O1/non-O139 Vibrio cholerae is a rare entity associated with high mortality rates. We report a case of non-O1/non-O139 V. cholerae bacteremia confirmed by polymerase chain reaction and agglutination tests. The clinicoepidemiological characteristics and therapeutic options for this infection are also described.

La bacteriemia por Vibrio cholerae no-O1/no-O139 es una entidad poco frecuente que se asocia con altas tasas de mortalidad. Se reporta un caso de bacteriemia por V. cholerae no-O1/no-O139 confirmado por reacción en cadena de la polimerasa y test de aglutinación. Se describen las características clinicoepidemiológicas y las opciones terapéuticas para esta infección.

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

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

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

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

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

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

[The pathogenicity of Cronobacter in the light of bacterial genomics]. / La patogenicidad de Cronobacter a la luz de la genómica bacteriana.

Introduction: Cronobacter spp. is a genus of Gram-negative bacteria belonging to the family Enterobacteriaceae. Species of the genus Cronobacter, particularly C. sakazakii, are implicated in the development of severe disease in newborns, which occurs with necrotizing enterocolitis, sepsis and meningitis. The disease has been frequently associated with powdered infant formula (PIF) and can therefore occur in the form of outbreaks. The genus Cronobacter has undergone extensive diversification in the course of its evolution, with some species being clearly pathogenic to humans while the impact of other species on human health is uncertain or unknown. Whole genome sequencing is used both in population genetic studies to identify the limited number of genotypes associated with the disease and to detect genes associated with antibiotic resistance or virulence, ultimately allowing more precise epidemiological links to be established between pediatric disease and infant foods.

Introducción: Cronobacter es un género de bacterias gramnegativas perteneciente a la familia Enterobacteriaceae. Algunas especies del género Cronobacter, en particular C. sakazakii, están implicadas en el desarrollo de infecciones neonatales graves, incluyendo meningitis, sepsis y enterocolitis necrotizante. La enfermedad se ha relacionado frecuentemente con los preparados en polvo para lactantes (PPL) y se puede presentar, por tanto, en forma de brotes. El género Cronobacter ha experimentado una amplia diversificación en el curso de su evolución, siendo algunas especies claramente patógenas para los humanos mientras que el impacto de otras especies sobre la salud humana es incierto o desconocido. La secuenciación genómica se utiliza en los estudios de genética de poblaciones tanto para identificar el limitado número de genotipos asociados a la enfermedad como para detectar los genes asociados a la virulencia, la adaptación al estrés o la resistencia a antibióticos, lo que permite, en definitiva, establecer vínculos epidemiológicos más precisos entre la enfermedad pediátrica y los alimentos infantiles.

Primer aislamiento y caracterización de la cepa prototipo del virus SARS-CoV-2 a inicios de la pandemia de la COVID-19 en el Perú

Introducción: Actualmente los contagios por el virus del SARS-CoV-2 supera los 600 millones de casos en el mundo. Objetivo: Aislar y caracterizar el virus SARS-CoV-2 causante de la COVID-19 a inicios de la pandemia en el Perú. Materiales y métodos: Se realizó el aislamiento viral a partir de 20 muestras de hisopado nasal y faríngeo positivas a SARS-CoV-2 por RT-PCR. El aislamiento se realizó en las líneas celulares Vero ATCC CCL-81 y Vero E6, evaluando el efecto citopático, la presencia del virus por RT-PCR, inmunofluorescencia indirecta (IFI) y posterior identificación por secuenciación genómica. Posteriormente, uno de los aislamientos de mayor circulación fue seleccionado y denominado cepa prototipo (PE/B.1.1/28549/2020), realizándose 10 pasajes sucesivos en células Vero ATCC CCL-81 para evaluar la dinámica de mutaciones. Resultados: Se observaron 11 aislamientos de virus por efecto citopático confirmándose por RT-PCR e IFI, de los cuales 6 fueron secuenciados identificándose los linajes B.1, B.1.1, B.1.1.1 y B.1.205, según el comité Pango de los genomas. La cepa prototipo corresponde a la variante B.1.1 y el análisis de las secuencias de los pasajes sucesivos mostró mutaciones a nivel de la proteína de la espiga (S) del virus, sin variación en la identidad del linaje. Conclusiones: Se aislaron 4 linajes en la línea celular Vero ATCC CCL-81. Los subcultivos en la misma línea celular muestran mutaciones en la proteína de la espiga, lo que indica mayor adaptabilidad a la célula hospedera y variación de la patogenicidad in vitro, comportamiento que le permite tener más éxito de supervivencia.

Introduction: Currently, infections caused by the SARS-CoV-2 virus exceed 600 million cases in the world. Objective: Isolation and characterization of the SARS-CoV-2 virus causing COVID-19 at the beginning of the pandemic in Peru. Materials and methods: Twenty nasal and pharyngeal swab samples were isolated from SARS-CoV-2 using two cell lines, Vero ATCC CCL-81 and Vero E-6; virus identification was performed by RT-PCR and the onset of cytopathic effect (CPE) was evaluated by indirect immunofluorescence and subsequent identification by genomic sequencing. One of the most widely circulating isolates were selected and named the prototype strain (PE/B.1.1/28549/2020). Then 10 successive passages were performed on Vero ATCC CCL-81 cells to assess mutation dynamics. Results: We detected 11 virus isolates by cytopathic effect, and subsequently confirmed by RT-PCR and indirect immunofluorescence. Of these, six were sequenced and identified as the lineages B.1, B.1.1, B.1.1.1, and B.1.205 according to the Pango lineage nomenclature. The prototype strain corresponded to lineage B.1.1. The analysis of the strains from the successive passages showed mutations mainly at in the spike (S) protein of the virus without variation in the identity of the lineage. Conclusions: Four lineages were isolated in the Vero ATCC CCL-81 cell line. Subcultures in the same cell line show mutations in the spike protein indicating greater adaptability to the host cell and variation in pathogenicity in vitro, a behavior that allows it to have more survival success.

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

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

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

Clostridioides difficile: Characterization of the circulating toxinotypes in an Argentinean public hospital / Clostridioides difficile: caracterización de los toxinotipos circulantes en un hospital público de Argentina

Abstract Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections.

Resumen Clostridioides difficile es un anaerobio esporulado que se asocia con episodios de diarreas hospitalarias. Su virulencia se encuentra vinculada, principalmente, a las toxinas TcdA y TcdB, codificadas por sus respectivos genes, tcdA y tcdB, que son parte de un locus de patogenicidad (PaLoc). Nuestro objetivo fue caracterizar los toxinotipos de C. difficile circulantes en un hospital público. Los genes tcdA y tcdB fueron amplificados y digeridos con diferentes enzimas de restricción: EcoRI para tcdA; HincII y AccI para tcdB. Además, se evaluó la presencia de cdtB (gen de la toxina binaria B) y de las toxinas A y B (por dot blot), así como el efecto citotóxico de sobrenadantes de cultivo sobre células Vero. En conjunto, estos estudios revelaron tres toxinotipos circulantes según la clasificación de Rupnik: 0, I y VIII; el más prevalente fue el último. Aunque son necesarios más estudios (ej., secuenciación), es interesante notar que la presencia del toxinotipo I podría estar relacionada con la introducción de bacterias de diferente origen geográfico. En los pacientes infectados con el toxinotipo VIII, el análisis multivariante de los resultados de laboratorio mostró que los aislamientos asociados a decesos (GCD13, GCD14 y GCD22) estaban situados en regiones de los biplots relacionados con valores de laboratorio alterados al momento de la internación. En los otros pacientes, aunque no se observó correlación entre los valores de laboratorio al momento de la internación y la evolución clínica, los niveles de urea, creatinina y recuento de glóbulos blancos estuvieron correlacionados positivamente entre sí una vez diagnosticada la infección. Nuestro estudio revela la circulación de diferentes toxinotipos de C. difficile en un mismo hospital público. La variedad de toxinotipos puede originarse a partir de microorganismos preexistentes en la región, así como también por la introducción de bacterias provenientes de otras regiones geográficas. La existencia de microorganismos con diferente potencial patogénico es relevante para el control, el seguimiento y el tratamiento de las infecciones.

Virulence genes of Aeromonas spp. isolates from stool in Spain.

INTRODUCTION: The role of Aeromonas species in gastrointestinal disease is controversial. The aim was to analyze not only the virulence genes between different species of Aeromonas isolated from feces, but the distribution of these virulence genes between enterotoxigenic strains and co-pathogen strains. METHODS: Retrospective study of isolates of Aeromonas spp. in feces (2016-2021). The protocol included coproculture, identification by MALDI-TOF and confirmation by multiplex PCR. SPSS Statistics program was used. RESULTS: A total of 288 strains were studied for the virulence genes between different species of Aeromonas. To compare virulence genes between Aeromonas as co-pathogen and those isolated alone, 218 strains of the global set were used; 52 as co-pathogens compared with 166 Aeromonas without associated pathogen as controls. CONCLUSIONS: We found no significant differences in the distribution of virulence genes versus co-existence of co-pathogens or not. A. hydrophila is the potentially most virulent species of our set.

Candida albicans the main opportunistic pathogenic fungus in humans.

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

Clostridioides difficile: Characterization of the circulating toxinotypes in an Argentinean public hospital.

Clostridioides difficile is a spore-forming anaerobe microorganism associated to nosocomial diarrhea. Its virulence is mainly associated with TcdA and TcdB toxins, encoded by their respective tcdA and tcdB genes. These genes are part of the pathogenicity locus (PaLoc). Our aim was to characterize relevant C. difficile toxinotypes circulating in the hospital setting. The tcdA and tcdB genes were amplified and digested with different restriction enzymes: EcoRI for tcdA; HincII and AccI for tcdB. In addition, the presence of the cdtB (binary toxin) gene, TcdA and TcdB toxins by dot blot and the cytotoxic effect of culture supernatants on Vero cells, were evaluated. Altogether, these studies revealed three different circulating toxinotypes according to Rupnik's classification: 0, I and VIII, being the latter the most prevalent one. Even though more studies are certainly necessary (e.g. sequencing analysis), it is worth noting that the occurrence of toxinotype I could be related to the introduction of bacteria from different geographical origins. The multivariate analysis conducted on the laboratory values of individuals infected with the most prevalent toxinotype (VIII) showed that the isolates associated with fatal outcomes (GCD13, GCD14 and GCD22) are located in regions of the biplots related to altered laboratory values at admission. In other patients, although laboratory values at admission were not correlated, levels of urea, creatinine and white blood cells were positively correlated after the infection was diagnosed. Our study reveals the circulation of different toxinotypes of C. difficile strains in this public hospital. The variety of toxinotypes can arise from pre-existing microorganisms as well as through the introduction of bacteria from other geographical regions. The existence of microorganisms with different pathogenic potential is relevant for the control, follow-up, and treatment of the infections.

Helicobacter pylori infection: A balance between bacteria and host.

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