AUTHOR=Fei Peng , Jiang Yichao , Jiang Yan , Yuan Xiujuan , Yang Tongxiang , Chen Junliang , Wang Ziyuan , Kang Huaibin , Forsythe Stephen J. 

TITLE=Prevalence, Molecular Characterization, and Antibiotic Susceptibility of Cronobacter sakazakii Isolates from Powdered Infant Formula Collected from Chinese Retail Markets

JOURNAL=Frontiers in Microbiology

VOLUME=8

YEAR=2017

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2017.02026

DOI=10.3389/fmicb.2017.02026

ISSN=1664-302X

ABSTRACT=<p><italic>Cronobacter sakazakii</italic> 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 <italic>C. sakazakii</italic> isolates from PIF purchased from Chinese retail markets. Two thousand and twenty PIF samples were collected from different institutions. Fifty-six <italic>C. sakazakii</italic> strains were isolated, and identified using <italic>fusA</italic> sequencing analysis, giving a contamination rate of 2.8%. Multilocus sequence typing (MLST) was more discriminatory than other genotyping methods. The <italic>C. sakazakii</italic> isolates were divided into 14 sequence types (STs) by MLST, compared with only seven clusters by <italic>ompA</italic> and <italic>rpoB</italic> sequence analysis, and four <italic>C. sakazakii</italic> serotypes by PCR-based O-antigen serotyping. <italic>C. sakazakii</italic> ST4 (19/56, 33.9%), ST1 (12/56, 21.4%), and ST64 (11/56, 16.1%) were the dominant sequence types isolated. <italic>C. sakazakii</italic> serotype O2 (34/56, 60.7%) was the primary serotype, along with o<italic>mpA</italic>6 and <italic>rpoB</italic>1 as the main allele profiles, respectively. Antibiotic susceptibility testing indicated that all <italic>C. sakazakii</italic> isolates were susceptible to ampicillin-sulbactam, cefotaxime, ciprofloxacin, meropenem, tetracycline, piperacillin-tazobactam, and trimethoprim-sulfamethoxazole. The majority of <italic>C. sakazakii</italic> strains were susceptible to chloramphenicol and gentamicin (87.5 and 92.9%, respectively). In contrast, 55.4% <italic>C. sakazakii</italic> strains were resistant to cephalothin. In conclusion, this large-scale study revealed the prevalence and characteristics of <italic>C. sakazakii</italic> from PIF in Chinese retail markets, demonstrating a potential risk for neonates and infants, and provide a guided to effective control the contamination of <italic>C. sakazakii</italic> in production process.</p>