Characterization of extended-spectrum beta-lactamase-producing Enterobacterales from organic and conventional chicken meats

Prevalence of AmpC, ESBL, and colistin resistance genes in Enterobacterales isolated from ready-to-eat food in Algeria

Antimicrobial resistance among bacteria present in ready-to-eat foods is an emerging concern. Hence, this study investigated the presence of extended-spectrum and AmpC β-lactamases (ESBL/AmpC)-producing Enterobacterales (ESBL-E) and the dissemination of mcr-1 in ESBL-E from ready-to-eat food samples (RTE) in Algeria. RTE food samples (n = 204) were aseptically collected and selectively cultured using MacConkey agar. The isolates were screened for ESBL production using the DDST test, confirmed ESBL-E isolates were identified using different conventional methods and MALDI-TOF MS, antibiotic susceptibility was determined using the disc diffusion and broth microdilution assay, ESBL-E isolates were analyzed for colistin and ESBL/AmpC encoding genes by PCR, and food samples were analyzed by univariate and multiple logistic regression. Overall, 48 (17.4%) of the 276 Enterobacterales were confirmed as ESBL producers, with a high prevalence in soups (40%), salads (25%), and cream-filled pastries (23.8%). Antibiotic susceptibility testing revealed that all the ESBL-E isolates were found multi-drug resistant. PCR revealed that blaTEM, blaCTX-M, blaCMY-2, blaOXA-1, and blaSHV were the most frequently detected. blaCTX-M-9 and blaCTX-M-1 were the predominant CTX-M types. Furthermore, four isolates were positive for mcr-1; three of them harbored the colistin resistance gene and ESBL/AmpC genes (2 E. cloacae and 1 S. enterica). To the best of our knowledge, this is the first report that detects the presence of the mcr-1 gene in ESBL-E strains isolated from RTE foods in Algeria. These findings suggest an urgent need for strict policies that prevent the spread and transmission of ESBL-E in food.

Disinfectant and heavy metal resistance profiles in extended spectrum β-lactamase (ESBL) producing Escherichia coli isolates from chicken meat samples

Biocidal compounds are frequently used as disinfectants in poultry industry and their widespread usage has risen concern due to the co-selection and persistence of antimicrobial resistance among bacteria. In this study, extended spectrum β-lactamase producing (ESBL) Escherichia coli isolates (n = 60) obtained from chicken meat were characterized by Pulsed Field Gel Electrophoresis (PFGE) and further tested for disinfectant and heavy metal resistance phenotypically and genotypically. Plasmid replicon types of these isolates were also determined. ESBL producing E. coli isolates were found to be resistant to ciprofloxacin (48.3 %) and gentamicin (15 %). The majority of these isolates (46.5 %) carried bla_CTX-M-55 gene. The isolates showed higher minimal inhibitory concentrations to cetylpyridinium chloride (90 %), cetyltrimethylammonium bromide (50 %), hexadecyltrimethylammonium bromide (46.7 %), triclosan (38.3 %), benzalkonium chloride (28.3 %), chlorhexidine (21.7 %), acriflavine (3.3 %), benzethonium chloride (1.7 %) and N-alkyl dimethyl benzyl ammonium chloride (1.7 %), but 18.3 % of the isolates were resistant to triclosan. Of the quaternary ammonium compounds (QACs) tolerance genes, mdfA, sugE(c), ydgE and ydgF were most present in all isolates, but the qacE, qacG, oqxA and oqxB genes were not detected. Of genes mediating the heavy metal resistance, the zitB gene was detected in all isolates, whereas the copA and cueO genes were detected in 96.67 % and 95 % of isolates, respectively. The IncFIB plasmid was commonly present (93.3 %) in ESBL producing E. coli isolates. Consequently, given the detection of genes mediating disinfectant and heavy metal resistance commonly in ESBL producing E. coli isolates as well as high rate of MICs against disinfectant compounds, the use of QACs for decontamination of the facilities may not be as effective as expected in poultry sector in Turkey.

Raw Meat Contaminated with Cephalosporin-Resistant Enterobacterales as a Potential Source of Human Home Exposure to Multidrug-Resistant Bacteria

The prevalence of cephalosporine-resistant (3GC-R) strains among United States community-related research samples ranged from 5.6 to 10.8%, while, in the European countries, it was 1.2% to 10.1%. Several studies suggest that meat of animal origin could be one of the reservoirs of 3GC-R bacteria. Here, 86 raw meat samples (turkey, pork, chicken and beef) were collected randomly and verified for the presence of 3GC-R bacteria. The 3GC-R bacteria were isolated, identified and characterized phenotypically (antibiotic resistance, motility and biofilm) and genotypically (repetitive-sequence-based rep-PCR) to elucidate any correlations with principal component analysis (PCA). From 28 3GC-R positive samples, 41 strains were isolated, from which the majority belonged to Serratia fonticola (39%), followed by Escherichia coli (19.5%), Enterobacter cloacae (17.1%) and Klebsiella pneumoniae (14.6%). The isolates of E. coli and S. fonticola presented diverse profiles in rep-PCR. Generally, 3GC-R strains were more resistant to antibiotics used in veterinary medicine than in human medicine. PCA derived from antibiotic resistance, motility and biofilm formation of S. fonticola and E. coli strains showed that resistance to beta-lactams was separated from the resistance to other antibiotic classes. Moreover, for the S. fonticola, E. coli and En. cloacae, the type of meat can create a specific tendency towards antibiotic resistance and phenotypic characteristics for S. fonticola, while these relationships were not found for other tested species.