Spread of ESBL/AmpC-producing Escherichia coli and Klebsiella pneumoniae in the community through ready-to-eat sandwiches in Algeria

- Sandwiches contaminated with ESBL/AmpC producers from 14% of the shops
- Up to three different ESBL/AmpC producers recovered from positive sandwiches
- ESBL/AmpC E. coli and K. pneumoniae clones mostly recovered
- Spread of the same ESBL/AmpC E. coli or K. pneumoniae clones among different shops
- Wide spread of ESBL/AmpC producers within the community through ready-to-eat fast food

The spread of Extended-Spectrum β-Lactamases (ESBLs) or AmpC β-Lactamases (AmpC) encoding genes in healthy human populations is of major concern. The role of the food chain has been questioned since numerous studies reported surface contamination of retail meat or crude vegetables with ESBL/AmpC-producing Enterobacteriaceae (ESBL/AmpC-E). Nonetheless, these food products are intended to be cooked or washed before consumption so that the risk of human transfer might be low. Here, the presence of ESBL/AmpC-E was investigated in ready-to-eat (RTE) sandwiches purchased in the street in the city of Bejaia, Algeria. Thirty ESBL/AmpC-producing E. coli (n = 18), K. pneumoniae (n = 11) and K. oxytoca (n = 1) were recovered from 21 sandwiches purchased in 14 of the 100 shops that were visited (14%). Twenty-four isolates (13 E. coli, 10 K. pneumoniae, 1 K. oxytoca) produced one or two ESBLs, while 5 E. coli and 1 K. pneumoniae isolates produced an AmpC. Among those, 12 E. coli harbored blaCTX-M-1 (n = 7), blaCTX-M-15 (n = 3), blaCTX-M-14 (n = 1) or blaCTX-M-2 (n = 1) and one E. coli co-harbored the blaCTX-M-15 and blaSHV-2 genes. The 10 K. pneumoniae displayed blaCTX-M-15 (n = 7), blaSHV-2 (n = 3), blaSHV-12 (n = 1) or blaCTX-M-1 (n = 1), including two isolates presenting a blaCTX-M-15/blaSHV-2 or blaCTX-M-1/blaSHV-2 combination. The K. oxytoca harbored the blaSHV-2 gene, and one K. pneumoniae and four E. coli displayed blaDHA and blaCMY-2, respectively. Most isolates (26/30, n = 87%) also possessed the aac(6′)-Ib-cr gene. Identical ESBL/AmpC-producing E. coli or K. pneumoniae clones were detected at different places across the city. This may reflect cross-contamination through poor handling practices, contaminated equipment, common ingredients or environmental factors. Of note, the emergent ST405 K. pneumoniae human clone was identified as a CTX-M-15 producer. This study highlights the presence of ESBL/AmpC-E in RTE sandwiches, which are a source of direct transfer to the human gut. These data indicate that fast food shops should be regarded as ESBL/AmpC reservoirs, and a risk for humans. Major efforts should be made in Algeria through guidelines on good practices in the food chain, and more globally in all countries sharing similar poor levels of food hygiene worldwide.