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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 bla CTX-M-1 (n = 7), bla CTX-M-15 (n = 3), bla CTX-M-14 (n = 1) or bla CTX-M-2 (n = 1) and one E. coli co-harbored the bla CTX-M-15 and bla SHV-2 genes. The 10 K. pneumoniae displayed bla CTX-M-15 (n = 7), bla SHV-2 (n = 3), bla SHV-12 (n = 1) or bla CTX-M-1 (n = 1), including two isolates presenting a bla CTX-M-15 /bla SHV-2 or bla CTX-M-1 /bla SHV-2 combination. The K. oxytoca harbored the bla SHV-2 gene, and one K. pneumoniae and four E. coli displayed bla DHA and bla CMY-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. [ABSTRACT FROM AUTHOR]

The aim of this study was to investigate the prevalence and molecular features of extended-spectrum cephalosporin resistance in Escherichia coli isolates contaminating ground beef at retail in Algeria. Of 371 ground beef samples, 27.5% were found to contain cefotaxime-resistant E. coli isolates distributed into A (24.5%), B1 (60.8%), and D (14.7%) phylogroups. A rate of 88.2% of isolates had a multidrug-resistance phenotype. All strains were producers of CTX-M type extended-spectrum β-lactamases (ESBLs): CTX-M-1, CTX-M-3, CTX-M-14, CTX-M-15, CTX-M-24, or CTX-M-32. Conjugation assays allowed the transfer of bla CTX-M-1 in association with IncI1 plasmids, bla CTX-M-15 with IncI1 and IncK+B/O plasmids, bla CTX-M-3 with IncK plasmids, and bla CTX-M-14 with IncF1B or IncK plasmids. Sequence analysis of gyrA and parC genes showed mutations in 98.6% of ciprofloxacin-resistant isolates. The patterns "GyrA: S83L+D87N, ParC: S80I" (46.5%) and "ParC: S80I" (42.3%) were predominant. qnrS1, qnrB, and aac(6')-Ib-cr were detected in 18.7% of isolates. The tet genes, tetA, tetB, and tetA+tetB, were present in 95.7% of tetracycline-resistant isolates. The sul genes (sul1, sul2, sul3, sul1+sul2, sul2+sul3, and sul1+sul3) and the dfr gene clusters (dfrA1, dfrA5, dfrA7, dfrA8, dfrA12, dfrA5+dfrA12, dfrA1+dfrA5, dfrA7+dfrA12, dfrA5+dfrA7, and dfrA1+dfrA5+dfrA7) were found in 96.4% and 85.5% of sulfamethoxazole/trimethoprim-resistant isolates, respectively. Classes 1 and 2 integrons were detected in 67.6% and 9.8% of isolates, respectively. This study highlighted the significant presence of resistance genes, in particular those of CTXM ESBLs, in the beef meat, with the risk of their transmission to humans through food chain.