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Abstract
The consumption of cheese in the People's Republic of China is increasing rapidly. Little is known about the microbiota, the presence of antibiotic-resistant bacteria, or the distribution of antibiotic resistance genes (ARGs) in commercially produced cheeses sold in China. This information is important for evaluating quality and safety. This study was conducted using 16S rRNA gene sequencing to assess the metagenomics of 15 types of cheese. Fourteen bacterial genera were detected, and Lactococcus, Lactobacillus, and Streptococcus were dominant based on number of sequence reads. Multidrug-resistant lactic acid bacteria (i.e., resistant to two or more types of antibiotic) were isolated from most of the types of cheese. Of these isolates, 100 and 91.7% were resistant to streptomycin and sulfamethoxazole, respectively, and genes involved in acquired resistance to streptomycin (strB) and sulfonamides (sul2) were detected with high frequency. To analyze the distribution of ARGs in the cheeses overall, 309 ARGs from eight categories and nine transposase genes were profiled. A total of 169 ARGs were detected in the 15 cheeses; their occurrence and abundance varied significantly between cheeses. Our study revealed diverse bacteria and ARGs in cheeses sold in China. The risks associated with multidrug resistance among dominant lactic acid bacteria are of great concern. HIGHLIGHTS Lactococcus, Lactobacillus, and Streptococcus were dominant bacteria in commercial cheeses. Multidrug-resistant lactic acid bacteria were isolated from most types of cheese sold in China. The diversity and abundance of ARGs varied significantly between cheeses.
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1 School of Agriculture and Biology, Shanghai Jiao Tong University, Shanghai, People's Republic of China 200240; Shanghai Municipal Veterinary Key Laboratory, Shanghai, People's Republic of China 200240
2 Technical Center for Animal, Plant and Food Inspection and Quarantine of Shanghai Customs, Shanghai, People's Republic of China 200135