Antimicrobial resistance, virulence genes, and ESBL (Extended Spectrum Beta-Lactamase) production analysis in E. coli strains from the Rio Grande/Rio Bravo River in Tamaulipas, Mexico.

The Rio Grande/Rio Bravo River is used as a major water supply for diverse recreational, household, and industrial activities in Northeast Tamaulipas, Mexico, and South Texas. In this study, we sampled surface water from 38 sites along Rio Grande/Rio Bravo River (Díaz Ordaz, Reynosa and Matamoros). We isolated 105 E. coli strains that were molecularly and phenotypically characterized. The percentage of virulence genes detected in E. coli were: hlyA (15.23%), stx2 (11.42%), stx1 (9.52%), bfp (0.95%), and eae (0.0) and combinations of stx1/stx2 (2.85%), stx2/hlyA (1.90%), stx1/bfp (0.95%) and stx2/bfp (0.95%) were detected in these strains. Resistance to more than one antibiotic was detected in 85.71%, and 5.71% of strains were extended-spectrum ß-lactamase-E. coli (ESBL-EC). These results indicate the presence of potentially pathogenic E. coli strains in the Rio Grande/Rio Bravo River; therefore, it can be considered a reservoir of pathogenic strains and represents a health risk for the population.

Virulence factors of A. caviae strains isolated from acute diarrheic disease in Cuba.

Fifty Aeromonas caviae strains from intestinal infection in different Cuban provinces were identified by the Aerokey II method and virulence factors were investigated. The strains did not produce haemolysins but other exoenzymes such as proteases, lipases, and DNases; additionally, all isolates adhered to the HEp-2 cell line by the Carrello method and this did not correlate with other virulence factors presence which demonstrates that the haemolysin phenotypic expression is not necessary for these strains to be pathogenic and that pathogenicity is multifactorial, each strain expressing at least one virulence factor.