2018年江西省婴幼儿食品中克罗诺杆菌污染状况及分子分型和耐药特征分析

目的 了解2018年江西省婴幼儿食品中克罗诺杆菌的污染情况、分子分型及耐药特征,为市售婴幼儿食品致病菌的溯源积累数据并为临床用药提供参考数据。方法 共采集市售婴幼儿食品337份,按照GB 4789.40—2016《食品安全国家标准 食品微生物学检验 克罗诺杆菌属(阪崎肠杆菌)检验》方法进行分离和鉴定,并采用基质辅助激光解析电离飞行时间质谱(MALDI-TOF MS)法对分离株进行验证,采用微量肉汤稀释法和脉冲场凝胶电泳(PFGE)技术进行药敏试验和分子分型试验。结果 168份婴幼儿配方奶粉中未检出克罗诺杆菌；169份婴幼儿谷类辅助食品中有24份检出克罗诺杆菌(24株),阳性率为14.2%。药敏试验显示,24株分离株共对8种抗生素耐药,头孢唑啉(62.5%,15/24)和甲氧苄啶/磺胺甲噁唑(29.2%,7/24)耐药率较高,全部菌株均对环丙沙星和亚胺培南敏感,其中1株分离株最高耐7种抗生素。PFGE结果显示分离株共有22种分子型别,相似度为46.6%～100.0%。结论 2018年江西省婴幼儿食品中克罗诺杆菌的污染情况与国内部分地区相似,克罗诺杆菌在婴幼儿谷类辅食中普遍存在,分离菌株对一、二代头孢菌素呈现不敏感趋势,PFGE型别高度多样化。

Analysis of the contamination, molecular typing and drug resistance of Cronobacter in infants and young children foods in Jiangxi Province in 2018

Objective To understand the contamination, molecular typing and drug resistance characteristics of Cronobacter in infants and young children foods in Jiangxi Province in 2018, and to provide reference data for infants and young children foods safety supervision, and clinical medication. Methods 337 commercially available infants and young children foods were collected, Cronobacter was isolated and identified according to GB 4789.40-2016 by matrix assisted laser desorption ionization-time of flight mass spectrometry(MALDI-TOF MS). The drug resistance test was performed on isolated strains via the broth microdilution method. Pulsed field gel electrophoresis(PFGE)was used to confirm the molecular type. Results Cronobacter was not detected in 168 infants and young children formulas; 24 Cronobacter isolates were isolated from 169 infants and young children cereal-based complementary food, with a positive rate of 14.2%. There was no difference in positive rate between rural and urban samples among the four seasons. Among the 13 antibiotics tested, 24 isolates were resistant to 8 kinds of antibiotics. The highest resistance rate was cefazolin (62.5%,15/24) and trimethoprim/sulfamethoxazole (29.2%,7/24). All isolates were sensitive to ciprofloxacin and imipenem. Besides, one isolate was resistant up to seven kinds of antibiotics. The result of PFGE showed that there were 22 molecular types in these isolates, and the similarity ranged from 46.6% to 100.0%. Conclusion The contamination of Cronobacter in infants and young children foods in Jiangxi Province in 2018 was similar to that in some parts of China,Cronobacter were prevalent in cereal-based supplements for infants and young children. Cronobacter isolates were not sensitive to the first and second generation cephalosporins, and PFGE molecular type of most isolates was highly diverse.