State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Public Laboratory for Applied and New Technology of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
State Key Laboratory of Applied Microbiology Southern China, Guangdong Provincial Public Laboratory for Applied and New Technology of Microbiology, Guangdong Provincial Key Laboratory of Microbial Culture Collection and Application, Guangdong Institute of Microbiology, Guangzhou 510070, China.
Int J Food Microbiol. 2015 Jul 2;204:17-23. doi: 10.1016/j.ijfoodmicro.2015.03.003. Epub 2015 Mar 6.
Cronobacter spp. are foodborne pathogens that cause rare but life-threatening diseases in neonates and infants; they can also cause disease in adults. Cronobacter spp. contamination of ready-to-eat (RTE) foods has been reported previously. However, to date, the prevalence and contamination levels of these bacteria in RTE foods in China have not yet been determined. Therefore, the aim of this study was to investigate the prevalence of Cronobacter spp. in RTE foods marketed in China. Two-hundred and eighty RTE food samples were collected from different producers and retailers and analyzed using quantitative methods. The isolates obtained were identified to the species level based on fusA sequences, and were subtyped using a PCR-based serotyping technique. Selected isolates were further characterized by multilocus sequence typing (MLST) and antimicrobial sensitivity determination. Of 280 samples tested, 52 (18.6%) were positive for Cronobacter spp. The contamination levels were less than 110 MPN/g for 78.8% (41/52) of the samples. The results of the O-antigen serotyping for 111 isolates showed that Cronobacter sakazakii serogroup O2 (28 isolates) was the most prevalent serotype. MLST analyses produced 41 sequence types (STs), including 20 novel STs. ST8 was the most prevalent ST (9 isolates) followed by ST4 (5 isolates). Antimicrobial sensitivity testing showed that 84.5% and 46.5% of the isolates were resistant to penicillin G and cephalothin, respectively; in contrast, all of the tested isolates were susceptible to cefotaxime, ciprofloxacin, tetracycline, and nalidixic acid. To the best of our knowledge, this is the first report on Cronobacter spp. prevalence in RTE foods in China, and the findings of our study nonetheless suggested that Cronobacter spp. contamination of Chinese RTE foods poses a potential risk for the consumer. Thus, the study highlights the significance of developing more effective control strategies during the manufacturing process.
阪崎克罗诺杆菌是食源性致病菌，可导致新生儿和婴儿发生罕见但危及生命的疾病，也可导致成人发病。先前已有报道称，即食食品（RTE）中存在阪崎克罗诺杆菌污染。然而，迄今为止，中国 RTE 食品中这些细菌的流行情况和污染水平尚未确定。因此，本研究旨在调查中国市场销售的 RTE 食品中阪崎克罗诺杆菌的流行情况。从不同的生产商和零售商采集了 280 份 RTE 食品样本，并采用定量方法进行分析。根据 fusA 序列将获得的分离株鉴定到种水平，并采用基于 PCR 的血清分型技术对其进行亚型分型。选择的分离株进一步通过多位点序列分型（MLST）和抗菌敏感性测定进行特征描述。在检测的 280 个样本中，有 52 个（18.6%）样本检测出阪崎克罗诺杆菌阳性。78.8%（41/52）的样本污染水平低于 110 MPN/g。111 个分离株的 O-抗原血清型分析结果显示，阪崎克罗诺杆菌 O2 血清群（28 个分离株）是最流行的血清型。MLST 分析产生了 41 个序列型（ST），包括 20 个新的 ST。最流行的 ST 是 ST8（9 个分离株），其次是 ST4（5 个分离株）。抗菌敏感性测试显示，84.5%和 46.5%的分离株分别对青霉素 G 和头孢噻吩耐药；相比之下，所有测试的分离株均对头孢噻肟、环丙沙星、四环素和萘啶酸敏感。据我们所知，这是中国首次报告即食食品中阪崎克罗诺杆菌的流行情况，我们的研究结果表明，中国 RTE 食品中阪崎克罗诺杆菌的污染对消费者构成潜在风险。因此，本研究强调了在生产过程中制定更有效的控制策略的重要性。
