Association Between Uropathogenic Escherichia coli Virulence Genes and Severity of Infection and Resistance to Antibiotics.

Purpose: Urinary tract infection (UTI) is the most frequent bacterial infection. Some uropathogenic Escherichia coli (UPEC) genes have been associated with disease severity and antibiotic resistance. The aim was to determine the association of nine UPEC virulence genes with UTI severity and antibiotic resistance of strains collected from adults with community-acquired UTI. Patients and Methods: A case-control study (1:3) (38 urosepsis/pyelonephritis and 114 cystitis/urethritis) was conducted. The fimH, sfa/foc, cvaC, hlyA, iroN, fyuA, ireA, iutA, and aer (the last five are siderophore genes) virulence genes were determined by PCR. The information of antibiotic susceptibility pattern of the strains was collected from medical records. This pattern was determined using an automated system for antimicrobial susceptibility testing. Multidrug-resistant (MDR) was defined as resistance to three or more antibiotic families. Results: fimH was the most frequently detected virulence gene (94.7%), and sfa/foc was the least frequently detected (9.2%); 55.3% (83/150) of the strains were MDR. The evaluated genes were not associated with UTI severity. Associations were found between the presence of hlyA and carbapenem resistance (Odds ratio [OR] = 7.58, 95% confidence interval [CI], 1.50-35.42), iutA and fluoroquinolone resistance (OR = 2.35, 95% CI, 1.15-4.84, and aer (OR = 2.8, 95% CI, 1.20-6.48) and iutA (OR = 2.95, 95% CI, 1.33-6.69) with penicillin resistance. In addition, iutA was the only gene associated with MDR (OR = 2.09, 95% CI,1.03-4.26). Conclusion: There was no association among virulence genes and UTI severity. Three of the five iron uptake genes were associated with resistance to at least one antibiotic family. Regarding the other four non-siderophore genes, only hlyA was associated with antibiotic resistance to carbapenems. It is essential to continue studying bacterial genetic characteristics that cause the generation of pathogenic and multidrug-resistant phenotypes of UPEC strains.

Immobilization Systems of Antimicrobial Peptide Ib-M1 in Polymeric Nanoparticles Based on Alginate and Chitosan.

The development of new strategies to reduce the use of traditional antibiotics has been a topic of global interest due to the resistance generated by multiresistant microorganisms, including Escherichia coli, as etiological agents of various diseases. Antimicrobial peptides are presented as an alternative for the treatment of infectious diseases caused by this type of microorganism. The Ib-M1 peptide meets the requirements to be used as an antimicrobial compound. However, it is necessary to use strategies that generate protection and resist the conditions encountered in a biological system. Therefore, in this study, we synthesized alginate and chitosan nanoparticles (Alg-Chi NPs) using the ionic gelation technique, which allows for the crosslinking of polymeric chains arranged in nanostructures by intermolecular interactions that can be either covalent or non-covalent. Such interactions can be achieved through the use of crosslinking agents that facilitate this binding. This technique allows for immobilization of the Ib-M1 peptide to form an Ib-M1/Alg-Chi bioconjugate. SEM, DLS, and FT-IR were used to determine the structural features of the nanoparticles. We evaluated the biological activity against E. coli ATCC 25922 and Vero mammalian cells, as well as the stability at various temperatures, pH, and proteases, of Ib-M1 and Ib-M1/Alg-Chi. The results showed agglomerates of nanoparticles with average sizes of 150 nm; an MIC of 12.5 µM, which was maintained in the bioconjugate; and cytotoxicity values close to 40%. Stability was maintained against pH and temperature; in proteases, it was only evidenced against pepsin in Ib-M1/Alg-Chi. The results are promising with respect to the use of Ib-M1 and Ib-M1/Alg-Chi as possible antimicrobial agents.

[Virulence mechanisms of enteropathogenic Escherichia coli]. / Mecanismos de virulencia de Escherichia coli enteropatógena.

Acute diarrheal disease (ADD) is a global public health problem, especially in developing countries and is one of the causes of mortality in children under five. ADD etiologic agents include viruses, bacteria and parasites in that order. Escherichia coli bacteria it is classified as a major diarrheagenic agent and transmitted by consuming contaminated water or undercooked foods. This review compiled updates on information virulence factors and pathogenic mechanisms involved in adhesion and colonization of seven pathotypes of E. coli called enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), shigatoxigenic E. coli (STEC), enteroaggregative E. coli (EAEC) and diffusely-adherent E. coli (DAEC). A final pathotype, adherent-invasive E. coli (AIEC) associated with Crohn's disease was also reviewed. The diarrheagenic pathotypes of E. coli affect different population groups and knowledge of the molecular mechanisms involved in the interaction with the human is important to guide research towards the development of vaccines and new tools for diagnosis and control.

Mecanismos de virulencia de Escherichia coli enteropatógena / Virulence mechanisms of enteropathogenic Escherichia coli

Acute diarrheal disease (ADD) is a global public health problem, especially in developing countries and is one of the causes of mortality in children under five. ADD etiologic agents include viruses, bacteria and parasites in that order. Escherichia coli bacteria it is classified as a major diarrheagenic agent and transmitted by consuming contaminated water or undercooked foods. This review compiled updates on information virulence factors and pathogenic mechanisms involved in adhesion and colonization of seven pathotypes of E. coli called enteropathogenic E. coli (EPEC), enterotoxigenic E. coli (ETEC), enteroinvasive E. coli (EIEC), shigatoxigenic E. coli (STEC), enteroaggregative E. coli (EAEC) and diffusely-adherent E. coli (DAEC). A final pathotype, adherent-invasive E. coli (AIEC) associated with Crohn's disease was also reviewed. The diarrheagenic pathotypes of E. coli affect different population groups and knowledge of the molecular mechanisms involved in the interaction with the human is important to guide research towards the development of vaccines and new tools for diagnosis and control.

La enfermedad diarreica aguda (EDA) es un problema de salud pública mundial, especialmente en los países en vía de desarrollo y es una de las causas de mortalidad en niños bajo cinco años de edad. Los agentes etiológicos de EDA incluyen virus, bacterias y parásitos, en ese orden. Dentro de las bacterias, Escherichia coli está clasificada como uno de los principales agentes diarreagénicos y se trasmite por el consumo de agua y alimentos contaminados o mal cocidos. Esta revisión recopiló información actualizada sobre los factores de virulencia y los mecanismos de patogenicidad implicados en la adhesión y colonización de siete patotipos de E. coli denominados, E. coli enteropatógena (ECEP), E. coli enterotoxigénica (ECET), E. coli enteroinvasora (ECEI), E. coli shigatoxigénica (ECST), E. coli enteroagregativa (ECEA) y E. coli de adherencia difusa (ECAD). Un último patotipo, E. coli adherente invasor (ECAI) asociado a la enfermedad de Crohn también fue revisado. Los patotipos diarreagénicos de E. coli afectan a diferentes grupos poblacionales y el conocimiento de los mecanismos moleculares implicados en la interacción con el humano es importante para orientar las investigaciones hacia el desarrollo de vacunas o nuevas herramientas para su diagnóstico y control.

Human Trypanosomiasis in the Eastern Plains of Colombia: New Transmission Scenario.

Characteristics of Trypanosoma cruzi infection were studied in a rural area of the eastern plains of Colombia. Using enzyme-linked immunosorbent assay and indirect fluorescent-antibody tests, the infection was determined in 11.6% of the inhabitants of 142 dwellings. During 6 months of community surveillance, in 42.3% dwellings, 609 triatomines were collected (597 Rhodnius prolixus and seven, three, one, and one of Panstrongylus geniculatus, Psammolestes arturi, Eratyrus mucronatus, and Triatoma maculata, respectively). Rhodnius prolixus was found in 80% peridomiciliary Attalea butyracea palms examined with baited traps, and its infection with T. cruzi was 30% and 38.5% in dwellings and palms, respectively. Trypanosoma cruzi was isolated in five of 35 triatomines and in one of 24 dogs. The blood of domestic and wild animals was identified in triatomines collected in the intradomicile and in palms. These results support the extension of the wild cycle of T. cruzi to human dwellings and the characterization of a new scenario for transmission in Colombia.

Epidemiology, risk factors and genotypes of HBV in HIV-infected patients in the northeast region of Colombia: high prevalence of occult hepatitis B and F3 subgenotype dominance.

INTRODUCTION: Chronic hepatitis B virus (HBV) infection is an increasing cause of morbidity and mortality in human immunodeficiency virus (HIV)-infected individuals. HIV-positive patients are commonly co-infected with HBV due to shared routes of transmission. OBJECTIVES: Our aim was to determine the risk factors, prevalence, genotypes, and mutations of the Surface S gene of HBV, and occult hepatitis B infection (OBI) among patients infected with HIV in a northeastern Colombian city. METHODS: A cross-sectional study was conducted with 275 HIV-positive patients attending an outpatient clinic in Bucaramanga, Colombia during 2009-2010. Blood samples were collected and screened for serological markers of HBV (anti-HBs, anti-HBc and HBsAg) through ELISA assay. Regardless of their serological profile, all samples were tested for the HBV S gene by nested-PCR and HBV genotypes were determined by phylogenetic inference. Clinical records were used to examine demographic, clinical, virological, immunological and antiretroviral therapy (ART) variables of HIV infection. RESULTS: Participants were on average 37±11 years old and 65.1% male. The prevalence of HIV-HBV coinfection was 12% (95%CI 8.4-16.4) of which 3.3% had active HBV infection and 8.7% OBI. The prevalence of HIV-HBV coinfection was associated with AIDS stage and ART treatment. Sequence analysis identified genotype F, subgenotype F3 in 93.8% of patients and genotype A in 6.2% of patients. A C149R mutation, which may have resulted from failure in HBsAg detection, was found in one patient with OBI. CONCLUSIONS: The present study found a high prevalence of HIV-HBV coinfection with an incidence of OBI 2.6-fold higher compared to active HBV infection. These findings suggest including HBV DNA testing to detect OBI in addition to screening for HBV serological markers in HIV patients.

Marcadores serológicos y moleculares de infección por el virus de la hepatitis B en estudiantes universitarios colombianos / Serological and molecular markers for Hepatitis B virus in university students

Introducción: Reportes de la OMS demuestran que la carga de infección por el virus de la hepatitis B (VHB) varía de acuerdo con la región geográfica y el grupo de riesgo. Propósito: Determinar la prevalencia de infección por el VHB y el estatus de vacunación en estudiantes universitarios de Bucaramanga. Metodología: Estudio descriptivo de corte transversal realizado en el 2010. Se incluyeron 1.298 estudiantes de cinco universidades. Se identificaron marcadores serológicos de infección para el VHB por ELISA y el genoma viral se detectó mediante PCR anidado. Resultados: Se estableció infección activa en 0,15%, confirmada por PCR; infección resuelta a 0,60%; 1,1% anti-HBc aislado, 30,2% vacunados y 67,9% susceptibles. No se evidenció hepatitis B oculta. Conclusiones: La baja prevalencia de infección por el virus de la hepatitis B reportada en el presente estudio contrasta con el patrón epidemiológico intermedio descrito en la región. Se encontró una baja cobertura de vacunación y ausencia de hepatitis B oculta en los estudiantes universitarios.

Introduction: Reports from the World Health Organization (WHO) show that the prevalence of hepatitis B virus (HBV) infections varies by geographical region and risk group. Purpose: The purpose of this study was to determine the prevalence of HBV infections, as well as the vaccination status, among university students from Bucaramanga. Methodology: This was a cross sectional study conducted in 2010 which included 1298 students from five universities. Serological markers for HBV infection were detected using ELISA. Viral genomes were detected with nested polymerase chain reaction (PCR). Results: Active infections were established in 0.15% of the study population, and this finding was confirmed by PCR. Resolved infections were identified in 0.60% of the population. Isolated anti-HBc antibodies were found, 30.2% of vaccinated individuals. 67.9% of the study population was susceptible. No occult HBV was detected. Conclusions: The low prevalence of HBV infections reported in this study contrasts with the intermediate epidemiological pattern described in the region. We found poor vaccination coverage and absence of occult hepatitis B among these university students.