Risk ranking and antimicrobial resistance of Shiga toxin-producing <i>Escherichia coli</i> of bovine origin.
The study found a 6.7% prevalence of STEC on cow hides, with 75% of isolates showing significant pathogenic potential. Only one isolate was resistant to multiple antibiotics, suggesting limited resistance overall.
Where it sits
this study against the rest of the efsubaglutide corpusSummary and findings
This study measured the prevalence and antimicrobial resistance of Shiga toxin-producing Escherichia coli (STEC) in 150 dairy cows at an Italian slaughterhouse. The prevalence was found to be 6.7% on hides and 4.0% on carcasses. The study also analyzed the virulence gene profiles of isolates and their resistance to various antibiotics.
Abstract
Shiga toxin-producing <i>Escherichia coli</i> (STEC) are zoonotic pathogens commonly carried by cattle and responsible for severe human diseases, as bloody diarrhoea (BD) and haemolytic uraemic syndrome (HUS). In an Italian slaughterhouse, 150 dairy cows were tested by swabbing the hides after stunning and the carcasses before refrigeration. STEC prevalence was 6.7% on hides and 4.0% on carcasses. No hide-to carcass contamination in the same animal was observed. Twenty isolates belonging to the serotypes O26:H11, O55:H9, O55:H12, O109:H10, O116:H28, O127:H12, O150:H2 (hides only), O157:H7 and O177:25 (hides and carcasses), O84:H2 and O177:H11 (carcasses only) were detected and analysed by Whole Genome Sequencing. Following published risk ranking schemes, STEC isolates were classified into seven groups according to their virulence gene profiles (stx1 and stx2 variants and the presence/absence of eae), in descending order from those most frequently associated with BD and HUS (groups I-V) to those considered least pathogenic (groups VI and VII). Overall, 75% of the isolates were assigned to groups I-V, highlighting the substantial pathogenic potential of the bovine strains. Regarding antimicrobial resistance, only one isolate (5%) was resistant to four or more antimicrobial classes, while 15% of the isolates carried ESBL-genes (blaCTX-M-1, or blaTEM-1 A, or blaTEM-1B) and displayed phenotypic resistance to ampicillin. Nevertheless, current therapeutic options of STEC infections suggest the use of azithromycin, a bacteriostatic agent that can avoid the progression of BD to HUS. Notably, all STEC isolates classified within groups I-V were susceptible to azithromycin, thus suggesting its potential usefulness in patient treatments.
Background
This study addresses the prevalence and antimicrobial resistance of Shiga toxin-producing Escherichia coli (STEC) in cattle, which are significant zoonotic pathogens linked to severe human diseases. Prior research has established the health risks associated with STEC, particularly in food safety contexts. Understanding the prevalence and resistance patterns in bovine sources is crucial for public health and food safety measures.
Methods
The study involved swabbing the hides and carcasses of 150 dairy cows at an Italian slaughterhouse. Primary outcome measures included the prevalence of STEC on hides and carcasses, as well as the antimicrobial resistance profiles of isolated strains. No specific dose or treatment duration was reported, as this was an observational study.
Results
The primary finding was a STEC prevalence of 6.7% on hides and 4.0% on carcasses. The study identified 20 isolates belonging to various serotypes, with 75% classified into virulence groups I-V. One isolate (5%) exhibited resistance to four or more antimicrobial classes, and 15% carried ESBL-genes.
Interpretation
The findings indicate a notable prevalence of pathogenic STEC strains in cattle, which aligns with previous literature highlighting the risks associated with these pathogens. While the statistical significance of the resistance findings is noted, the clinical implications may be limited due to the small proportion of resistant isolates. The study's single-site design and limited sample size may confound the generalizability of the results.
Key findings
- 6.7% STEC prevalence on hides, n=150.
- 4.0% STEC prevalence on carcasses, n=150.
- 75% of isolates assigned to virulence groups I-V.
- 5% of isolates resistant to four or more antimicrobial classes.
- 15% of isolates carried ESBL-genes and were phenotypically resistant to ampicillin.
Limitations
- single-site study may not represent broader populations
- small sample size of n=150
- no treatment or follow-up data reported
- observational design limits causal inferences