AUTHOR=Fei Peng , Jing He , Ma Yan , Dong Gege , Chang Yunhe , Meng Zhaoxu , Jiang Shilong , Xie Qinggang , Li Shuzhen , Chen Xi , Yang Weiwei 

TITLE=Cronobacter spp. in Commercial Powdered Infant Formula Collected From Nine Provinces in China: Prevalence, Genotype, Biofilm Formation, and Antibiotic Susceptibility

JOURNAL=Frontiers in Microbiology

VOLUME=13

YEAR=2022

URL=https://www.frontiersin.org/journals/microbiology/articles/10.3389/fmicb.2022.900690

DOI=10.3389/fmicb.2022.900690

ISSN=1664-302X

ABSTRACT=<p>The purpose of this study was to investigate the prevalence of <italic>Cronobacter</italic> spp. in commercial powdered infant formula (PIF) from nine provinces in China from March 2018 to September 2020, and to reveal the genotype, biofilm-forming ability, and antibiotic susceptibility of these isolates. A total of 27 <italic>Cronobacter</italic> strains, consisting of 22 <italic>Cronobacter sakazakii</italic> strains, 3 <italic>Cronobacter malonaticus</italic> strains, 1 <italic>Cronobacter turicensis</italic> strain, and 1 <italic>Cronobacter dublinensis</italic> strain, were isolated from 3,600 commercial PIF samples with a prevalence rate of 0.75%. Compared with the other 8 provinces, PIF from Shaanxi province had a higher prevalence rate (1.25%) of <italic>Cronobacter</italic> spp. These isolates were divided into 14 sequence types (STs), and 6 <italic>Cronobacter</italic> serotypes. The main <italic>Cronobacter</italic> STs were ST4, ST1, and ST64, and the dominant <italic>Cronobacter</italic> serotype was <italic>C. sakazakii</italic> serotype O2. Approximately 88.89% of <italic>Cronobacter</italic> isolates had a strong ability (OD<sub>595</sub> &gt; 1) to form biofilms on tinplate, among which the strains with ST4 were more dominant. All isolates were susceptible to ampicillin-sulbactam, ceftriaxone, cefotaxime, sulfadiazine, sulfadoxine, trimethoprim-sulfamethoxazole, gentamicin, tetracycline, ciprofloxacin, and colistin, while 55.56 and 96.30% isolates were resistant to cephalothin and vancomycin, respectively. Taken together, our findings highlighted the contamination status and characterization of <italic>Cronobacter</italic> spp. in commercial PIF from nine provinces of China, and provided guidance for the effective prevention and control of this pathogen in the production of PIF.</p>