Reservoir Of Pathogenic Strains Research Articles

Antimicrobial resistance, virulence genes, and ESBL (Extended SpectrumBeta-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 β-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.

Phenotypic and genotypic analysis of Pseudomonas syringae recovered from symptomatic beans and associated weeds in Northern Spain

Thirty isolates of Pseudomonas syringae other than pathovar (pv.) phaseolicola, recovered from beans (18) and weeds (12) in a Northern Spanish region, were studied by a polyphasic approach, including phenotypic tests, detection of levansucrase and toxin (syringomycin and syringopeptin) genes, typing by RAPD (Random Amplified Polymorphic DNA) and PFGE (Pulsed-Field Gel Electrophoresis). The isolates were phenotypically heterogeneous, and both RAPD and PFGE, probed to be highly discriminative, as they were almost able to differentiate at the level of isolate. Phylogenetic analysis based on conserved genes of the core genome (rpoD, gltA and gyrB) distributed the isolates in three different clades (2A, 2B and 2C) belonging to phylogroup 2 of the P. syringae complex. According to toxin production, 18 of them, within clade 2B, were assigned to P. syringae pv. syringae and five of these caused symptoms after experimental inoculation on bean pods. Four of the five pathogenic isolates were obtained from weeds, supporting the role of weeds associated with bean crops, particularly Cyperus rotundus, Malva sylvestris, and Polygonum lapathifolium, as a reservoir of the pathogen. In conclusion, results of this study suggest that apart from P. syringae pv. phaseolicola, P. syringae isolates circulating in our region are mostly epiphytes, and support the role of weeds associated with bean crops as reservoir of pathogenic strains of P. syringae pv. syringae.