Extended-spectrum β-lactamase-producing Enterobacteriaceae in different environments (humans, food, animal farms and sewage)

Objectives: This study aimed to determine the presence of extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae in different environments. Methods: Clinical samples and stool samples from animal farms, sewage, human faecal carriers attending the emergency room and faecal carriers in the context of food-borne disease outbreaks were subcultured onto MacConkey agar supplemented with cefotaxime for the detection of ESBL-producing Enterobacteriaceae. Identification, susceptibility pattern and ERIC-PCR were used for clone delineation in each sample. Community consumption of antibiotics was also recorded. Results: An ESBL-producing Enterobacteriaceae prevalence of 1.9% was observed in human infections. A cross-sectional survey of human faecal carriers in the community showed a general prevalence of 6.6% with a temporal distribution. High use of antibiotics in winter coincided with a lower prevalence in carriers. ESBL-producing Enterobacteriaceae were detected in the five samples of human sewage, in samples from 8 of 10 pig farms, 2 of 10 rabbit farms, from all 10 poultry farms and in 3 of 738 food samples studied. Faecal carriage of ESBL-producing Enterobacteriaceae was detected in samples from 19 of 61 food-borne outbreaks evaluated. All food-borne outbreaks were due to enteropathogens. The prevalence of carriers in these outbreaks ranged from 4.4% to 66.6%. Conclusions: This widespread occurrence of ESBL-producing Enterobacteriaceae suggests that the community could act as a reservoir and that food could contribute to the spread of these strains.