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Front. Microbiol. | doi: 10.3389/fmicb.2017.02026

Prevalence, molecular characterization and antibiotic susceptibility of Cronobacter sakazakii isolates from powdered infant formula collected from Chinese retail markets

Peng Fei1, Yichao Jiang2, Yan Jiang3, Xiujuan Yuan4, Tongxiang Yang1, Junliang chen1, Ziyuan Wang1, Huaibin Kang1* and Stephen Forsythe5*
  • 1Henan University of Science and Technology, China
  • 2Changbai Mountains Food and Drug Inspection Testing Center, China
  • 3MuLing Food Inspection Testing Center, Department of Market Supervision and Management, China
  • 4Anda Department of Animal Husbandry and Veterinary, China
  • 5Foodmicrobe.com, Adams Hill, Keyworth, United Kingdom

Cronobacter sakazakii is an opportunistic pathogen that causes severe infections in neonates and infants through contaminated powdered infant formula (PIF). Therefore, the aim of this study was a large-scale study on determine the prevalence, molecular characterization and antibiotic susceptibility of C. sakazakii isolates from PIF purchased from Chinese retail markets. Two thousand and twenty PIF samples were collected from different institutions. Fifty-sixt C. sakazakii strains were isolated, and identified using fusA sequencing analysis, giving a contamination rate of 2.8%. Multilocus sequence typing (MLST) was more discriminatory than other genotyping methods. The C. sakazakii isolates were divided into 14 sequence types (STs) by MLST, compared with only 7 clusters by ompA and rpoB sequence analysis, and 4 C. sakazakii serotypes by PCR-based O-antigen serotyping. C. sakazakii ST4 (19/56, 33.9%), ST1 (12/56, 21.4%), and ST64 (11/56, 16.1%) were the dominant sequence types isolated. C. sakazakii serotype O2 (34/56, 60.7%) was the primary serotype, along with ompA6 and rpoB1 as the main allele profiles, respectively. Antibiotic susceptibility testing indicated that all C. sakazakii isolates were susceptible to ampicillin-sulbactam, cefotaxime, ciprofloxacin, meropenem, tetracycline, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. The majority of C.sakazakii strains were susceptible to chloramphenicol and gentamicin (87.5% and 92.9%, respectively). In contrast, 55.4% C.sakazakii strains were resistant to cephalothin. In conclusion, this large-scale study revealed the prevalence and characteristics of C. sakazakii from PIF in Chinese retail markets, demonstrating a potential risk for neonates and infants, and provide a guided to effective control the contamination of C. sakazakii in production process.

Keywords: C. sakazakii, Prevalence, genotyping, antibiotic susceptibility, Powdered infant formula (PIF)

Received: 23 Jul 2017; Accepted: 04 Oct 2017.

Edited by:

Javier Carballo, University of Vigo, Spain

Reviewed by:

Gonçalo N. Almeida, Instituto Nacional de Investigação Agrária e Veterinária, Portugal
Ondřej Holý, Palacký University, Olomouc, Czechia  

Copyright: © 2017 Fei, Jiang, Jiang, Yuan, Yang, chen, Wang, Kang and Forsythe. This is an open-access article distributed under the terms of the Creative Commons Attribution License (CC BY). The use, distribution or reproduction in other forums is permitted, provided the original author(s) or licensor are credited and that the original publication in this journal is cited, in accordance with accepted academic practice. No use, distribution or reproduction is permitted which does not comply with these terms.

* Correspondence:
Prof. Huaibin Kang, Henan University of Science and Technology, Luoyang, China, khbin001@163.com
Prof. Stephen Forsythe, Foodmicrobe.com, Adams Hill, Keyworth, Nottingham, United Kingdom, sforsythe4j@gmail.com