Distribution and Characterization of Antimicrobial Resistant Pathogens in a Pig Farm, Slaughterhouse, Meat Processing Plant, and in Retail Stores.

The emergence of antibiotic resistance in foodborne pathogens isolated from meat pro-ducts and their producing environment has been an increasing and leading threat to public health. The aim of the study was to identify pathogens and their antimicrobial resistance isolated from pig production to pork meat distribution phases. Through this study, food spoilage and foodborne or clinical pathogenic bacteria were isolated and identified from pork (belly and neck) meat product and its related environmental samples that include pig swabs, diets, feces, liquid manure, workers' gloves, dust fan swabs, carcass swabs, floor swabs, and drain water in the affiliated farm, slaughterhouse, meat processing plant, and in retail stores. All carcasses at the slaughterhouse and meat products at the meat processing plant were tracked from pigs at a targeted farm. Nine different selective media agars were used to effectively isolate various pathogenic bacteria. A total of 283 presumptive pathogenic bacteria isolated from 126 samples were selected and identified using MALDI-ToF MS. Twenty-three important foodborne pathogens were identified, and some of them, Shiga-toxin-producing E. coli (STEC), Listeria monocytogenes, Staphylococcus aureus, and Yersinia enterocolitica, were further confirmed using PCR. The PFGE patterns of 12 STEC isolates were grouped by sample source or site. All the foodborne pathogens used in the study were not resistant to amoxicillin/clavulanate, ciprofloxacin, and gentamicin, whereas some of the STEC, L. monocytogenes, and S. aureus isolates were resistant to various antibiotics, including ampicillin, erythromycin, tetracycline, and vancomycin. The most common antimicrobial resistance pattern in the pathogenic STEC isolates was AMP-KAN-STR-SXT-TET. Consequently, this study provides valuable information for the distribution of antimicrobial-resistant pathogens along the pork meat production chain and can assist farmers and stakeholders to develop a systematic strategy for reducing the current emergence and spread of antimicrobial resistance in the different phases of pig production and distribution.

Development of a selective media for detecting Campylobacter spp. in chicken carcasses using avibactam supplemented mCCDA.

Campylobacter spp. are major causes of gastrointestinal infections worldwide, and are commonly identified using modified-charcoal-cefoperazone-deoxycholate agar (mCCDA). However, the efficacy of this screening technique is often hindered by overgrowth of competing flora, such as extended-spectrum ß-lactamase (ESBL)-producing Escherichia coli. Thus, in the present study we supplemented mCCDA with a recently developed ESBL inhibitor, avibactam (A-mCCDA). We inoculated mCCDA and A-mCCDA plates with 25 strains each of Campylobacter spp. and ESBL-producing E. coli, and thereby determined that the optimum avibactam concentration required to inhibit ESBL-producing E. coli was 0.0625 mg/L. At this concentration, a significantly higher proportion of Campylobacter spp. was isolated using A-mCCDA compared to that using mCCDA (P < 0.05). Thus, the results of the present study support the use of A-mCCDA to improve current Campylobacter screening methods.