Characterization of commensal Escherichia coli isolates from slaughtered sheep in Mexico

Abstract

Introduction: Commensal Escherichia coli is defined as bacteria without known virulence factors that could be playing a specific role in some diseases; however, they could be responsible to disseminate antimicrobial resistance genes to other microorganisms. This study aimed to characterize the commensal E. coli isolates obtained from slaughtered sheep in the central region of Mexico.
 Methodology: Isolates were classified as commensal E. coli when distinctive genes related to diarrheagenic pathotypes (stx1, stx2, eae, bfp, LT, stp, ipaH, and aggR) were discarded by PCR. Identification of serotype, phylogenetic group, and antimicrobial resistance was also performed.
 Results: A total of 41 isolates were characterized. The phylogenetic groups found were B1 in 37 isolates (90.2%), A in 2 (4.8%), and 1 isolate (2.4%) for C and D groups. Serotypes associated with diarrhea in humans (O104:H2 and O154:NM) and hemolytic uremic syndrome (O8:NM) were detected. Thirty-three isolates (80%) were resistant to ceftazidime, 23 (56%), to tetracycline 8 (19.5%) to ampicillin, and 1 to amikacin. Six isolates (14.6%) were multidrug-resistant.
 Conclusions: This study provides new information about commensal E. coli in slaughtered sheep, high percentages of resistance to antibiotics, and different profiles of antimicrobial resistance were found, their dissemination constitute a risk factor towards the consuming population.

Shiga Toxin Subtypes, Serogroups, Phylogroups, RAPD Genotypic Diversity, and Select Virulence Markers of Shiga-Toxigenic Escherichia coli Strains from Goats in Mid-Atlantic US

“…Isolates with similar Shiga toxin subtypes were also detected in cattle in Mexico [52]. The O8 serogroup has been isolated in humans with urinary tract infections [53,54] and bloody diarrhea [55] and in animals-diarrheic lambs, calves [56][57][58], and pigs [59,60] as well as healthy sheep [61]. These results further underscore the importance of STEC from goats.…”

Ecotype-specific genomic features within theEscherichiacryptic clade IV

“…Cryptic clade I is closely related to E. coli and genomic studies indicate that both groups carry common virulence factors, which suggests that clade I strains could also be as pathogenic as some E. coli strains (Steinsland et al, 2010;Walk, 2015). Bacterial virulence factors encode genes that facilitate infection, such as toxins or proteins needed for bacterial adherence (Holden et al, 2009;Stecher and Hardt, 2011;Acosta-Dibarrat et al, 2021). The presence of virulence and antibiotic resistance factors in bacterial genomes is often linked to specific selection pressures associated with hosts (Jernberg et al, 2010;Becattini et al, 2016).…”