College of Food Science and Engineering, Qingdao Agricultural University, Qingdao 266109, Shandong, People's Republic of China.
Haidu College, Qingdao Agricultural University, Laiyang 265200, Shandong, People's Republic of China.
J Food Prot. 2021 Nov 1;84(11):1863-1867. doi: 10.4315/JFP-21-094.
Fresh Milk Bar (FMB), an emerging dairy retail franchise, is used to instantly produce and sell pasteurized milk and other dairy products in China. However, the quality and safety of pasteurized milk in FMB have received little attention. The objective of this study was to investigate the prevalence, antimicrobial resistance, and virulence genes of Escherichia coli, Staphylococcus aureus, and Streptococcus in 205 pasteurized milk samples collected from FMBs in China. Four (2.0%) isolates of E. coli, seven (3.4%) isolates of S. aureus, and three (1.5%) isolates of Streptococcus agalactiae were isolated and identified. The E. coli isolates were resistant to amikacin (100%), streptomycin (50%), and tetracycline (50%). Their detected resistance genes include aac(3)-III (75%), blaTEM (25%), aadA (25%), aac(3)-II (25%), catI (25%), and qnrB (25%). The S. aureus isolates were mainly resistant to penicillin G (71.4%), trimethoprim-sulfamethoxazole (71.4%), kanamycin (57.1%), gentamicin (57.1%), amikacin (57.1%), and clindamycin (57.1%). blaZ (42.9%), mecA (28.6%), ermB (14.3%), and ermC (14.3%) were detected as their resistance genes. The Streptococcus strains were mainly resistant to tetracycline (66.7%) and contained the resistance genes pbp2b (33.3%) and tetM (33.3%). The virulence genes eae and stx2 were only found in one E. coli strain (25%), sec was detected in two S. aureus strains (28.6%), and bca was detected in one S. agalactiae strain (33.3%). The results of this study indicate that bacteria with drug resistance and virulence genes isolated from the pasteurized milk of FMB are a potential risk to consumers' health.
鲜牛奶吧（FMB）是一种新兴的乳制品零售连锁店，用于在中国即时生产和销售巴氏奶和其他乳制品。然而，FMB 中巴氏奶的质量和安全性尚未得到充分关注。本研究的目的是调查从中国 FMB 采集的 205 份巴氏奶样本中大肠杆菌、金黄色葡萄球菌和无乳链球菌的流行情况、耐药性和毒力基因。从巴氏奶样本中分离出 4（2.0%）株大肠杆菌、7（3.4%）株金黄色葡萄球菌和 3（1.5%）株无乳链球菌。大肠杆菌分离株对阿米卡星（100%）、链霉素（50%）和四环素（50%）耐药。其检测到的耐药基因包括 aac(3)-III（75%）、blaTEM（25%）、aadA（25%）、aac(3)-II（25%）、catI（25%）和 qnrB（25%）。金黄色葡萄球菌分离株主要对青霉素 G（71.4%）、甲氧苄啶-磺胺甲恶唑（71.4%）、卡那霉素（57.1%）、庆大霉素（57.1%）、阿米卡星（57.1%）和克林霉素（57.1%）耐药。blaZ（42.9%）、mecA（28.6%）、ermB（14.3%）和 ermC（14.3%）被检测为其耐药基因。链球菌菌株主要对四环素（66.7%）耐药，含有耐药基因 pbp2b（33.3%）和 tetM（33.3%）。仅在 1 株大肠杆菌（25%）中发现了毒力基因 eae 和 stx2，在 2 株金黄色葡萄球菌（28.6%）中检测到 sec，在 1 株无乳链球菌（33.3%）中检测到 bca。本研究结果表明，从 FMB 巴氏奶中分离出的耐药性和毒力基因的细菌对消费者的健康构成潜在威胁。
