The objective of this study was to determine the prevalence of enterohemorrhagic Escherichia coli (EHEC), E. coli O157, Salmonella, and Listeria monocytogenes in retail food samples from Seattle, Wash. A total of 2,050 samples of ground beef (1,750 samples), mushrooms (100 samples), and sprouts (200 samples) were collected over a 12-month period and analyzed for the presence of these pathogens. PCR assays, followed by culture confirmation were used to determine the presence or absence of each organism. Of the 1,750 ground beef samples analyzed, 61 (3.5%) were positive for EHEC, and 20 (1.1%) of these were positive for E. coli O157. Salmonella was present in 67 (3.8%) of the 1,750 ground beef samples. Of 512 ground beef samples analyzed, 18 (3.5%) were positive for L. monocytogenes. EHEC was found in 12 (6.0%) of the 200 sprout samples, and 3 (1.5%) of these yielded E. coli O157. Of the 200 total sprout samples, 14 (7.0%) were positive for Salmonella and none were positive for L. monocytogenes. Among the 100 mushroom samples, 4 (4.0%) were positive for EHEC but none of these 4 samples were positive for E. coli O157. Salmonella was detected in 5 (5.0%) of the mushroom samples, and L. monocytogenes was found in 1 (1.0%) of the samples.

This study was focused on the prevalence and antimicrobial susceptibilities of Salmonella directly isolated at animal clinics in Guangdong, People's Republic of China. The isolation rates from chickens, ducks, and pigs were 11.3% (11 of 97 samples), 15.4% (53 of 344 samples), and 3.0% (13 of 434 samples), respectively. Among the 77 Salmonella enterica isolates, the most predominant serovar was Typhimurium (81.8%, 63 isolates), followed by serovars Meleagridis (2.6%, 2 isolates) and Abaetetuba (1.3%, 1 isolate). Salmonella isolates were resistant to ciprofloxacin (16.9% of isolates) and nalidixic acid (66.2% of isolates), and 68 isolates (88.3%) were multidrug resistant, displaying resistance to three or more classes of antimicrobial agents. Eighteen isolates (23.4%) had at least one plasmid-mediated quinolone resistance gene, which was identified using PCR and DNA sequencing. The most prevalent plasmid-mediated quinolone resistance gene was aac(6')-Ib-cr, found in 14 isolates (18.2%), followed by oqxAB (9.1%) and qnrS (7.8%). Alterations in the gyrA gene were detected in 24 (57.1%) of 42 strains with a ciprofloxacin MIC of ≥0.25 μg/mL; the same level of susceptibility was found for enrofloxacin. Six types of mutations were found in the quinolone resistance determining regions of gyrA, and the predominant one (S83Y) was found singly in 15 (62.5%) of 24 isolates. We also found 22 different pulsed-field gel electrophoresis types among the Salmonella isolates. The Salmonella serovars and MICs of ciprofloxacin were similar within clusters, although individual differences were noted. This finding suggests that resistance plasmids were horizontally transmitted but also clonally spread.

Abstract Objectives This study was designed to understand the prevalence of antibiotic-resistant bacteria in the Beijing subway environment and the potential transmission of carbapenem-resistant Enterobacteriaceae in a public transportation environment. Methods Carbapenem-resistant isolates were selected on brain heart infusion agar supplemented with meropenem (0.5 mg/L) and antimicrobial susceptibility testing was conducted using the broth microdilution method. WGS analyses were conducted for 11 Klebsiella pneumoniae isolates to identify resistance genes. The genetic relationships among the isolates were evaluated by MLST and PFGE. Results We identified 11 carbapenem-resistant K. pneumoniae isolates from the Beijing subway environment. WGS revealed three STs among the 11 isolates, with 9 isolates classified as ST726 and containing a blaNDM-5-carrying IncX3 plasmid. The genetic environment of blaNDM-5 was very similar to that observed in other blaNDM-5-containing clinical isolates. Conclusions The presence of carbapenem-resistant Enterobacteriaceae in a public transportation environment is concerning and indicates that regular antimicrobial resistance surveillance is urgent and necessary.

What is already known about this topic?Salmonella causes acute and chronic diseases in food animals, and infected food animals are one of the most important source of human infection. What does this report contribute?The prevalence of Salmonella was 10.5% in chicken samples, 24.4% in pig, 23.3% in duck, and 29.4% in milk. Salmonella isolates were highly resistant to ampicillin (59.60%). What are the implications for public health practices?Data on Salmonella infections among food animals in China could help identify sources and factors related to the spread of Salmonella in food animals and food production chains.

Objectives Recently, epidemiological research has shown an unusually high prevalence of telithromycin-resistant Campylobacter. This study was designed to investigate the potential resistance mechanism of telithromycin resistance in Campylobacter. Methods A total of 122 Campylobacter isolates of chicken origin collected in 2019 from three regions of China were tested for susceptibility to telithromycin. The potential mechanism of resistance to telithromycin in Campylobacter was revealed through WGS analysis and natural transformation. Results In this study, 51.3% (61/119) of Campylobacter coli and 100.0% (3/3) of Campylobacter jejuni were resistant to telithromycin. erm(B) or A2075G mutation in 23S rRNA (23S_A2075G) was identified in the telithromycin-resistant C. coli. Cloning of the erm(B) or 23S_A2075G into C. jejuni NCTC 11168 resulted in a 256-fold increase in the MIC of telithromycin. MLST results indicated that various STs were involved in the dissemination of 23S_A2075G and erm(B). Phylogenetic analysis showed that the C. coli isolates with 23S_A2075G and erm(B) from chickens and humans were closely related. Conclusions 23S_A2075G and erm(B), which have been widely spread in different genotypes of C. coli isolated from animals and humans, could mediate high levels of resistance to telithromycin in C. coli. C. coli containing 23S_A2075G or erm(B) are clonally related and have the potential to spread zoonotic diseases.