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

Abstract

The purpose of this study was to investigate the prevalence of Cronobacter 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 Cronobacter strains, consisting of 22 Cronobacter sakazakii strains, 3 Cronobacter malonaticus strains, 1 Cronobacter turicensis strain, and 1 Cronobacter dublinensis 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 Cronobacter spp. These isolates were divided into 14 sequence types (STs), and 6 Cronobacter serotypes. The main Cronobacter STs were ST4, ST1, and ST64, and the dominant Cronobacter serotype was C. sakazakii serotype O2. Approximately 88.89% of Cronobacter isolates had a strong ability (OD595 > 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 Cronobacter 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.

Diverse Genotypes of Cronobacter spp. Associated with Dairy Farm Systems in Jiangsu and Shandong Provinces in China

“…A total of eleven Cronobacter serogroups were recognized in this study. C. sakazakii O1 and O2 were the dominant serotypes, in accordance with a previous study from China which investigated commercial powdered infant formula [ 8 ]. Additionally, another previous study showed that C. sakazakii serotypes O1, O2, and O4, and C. malonaticus serotype O2 were particularly significant in clinical cases and were probably related to human infections [ 38 ].…”

“…are sensitive to conventional antimicrobials, but the proportion of Cronobacter spp. exhibiting multiple-drug resistance is still increasing year by year [ 8 , 9 ]. Therefore, understanding the prevalence of Cronobacter and its antibiotic resistance in farming systems will help develop effective monitoring systems and contribute to improving public health and help control the spread of antibiotic resistance.…”

Characterization of Cronobacter sakazakii and Cronobacter malonaticus Strains Isolated from Powdered Dairy Products Intended for Consumption by Adults and Older Adults

“…examined showed resistance genes for beta-lactamases CSA-1 and CMA-1, which was consistent with the observed in vitro resistance to the cephalosporin KF. Since the initial report on the bla CSA and bla CMA gene family responsible for cephalosporin resistance in Cronobacter spp., resistance to KF has been documented in various clinical and environmental strains in different countries worldwide [65][66][67][68][69]. Additionally, we detected the presence of the mrc 9.1 gene, which confers resistance to colistin (polymyxin), considered a gene of significant concern in public health.…”

Isolation and Molecular identification of Cronobacter sakazakii isolated from different foodstuffs and infant stools

“…Although culture methods are important for Cronobacter spp detection, they are time-consuming and involve complex steps (Chen et al, 2018;Armstrong et al2019). The molecular characteristics of C. sakazakii, which is isolated from powdered milk infant formula and other sources, can be revealed through genotyping, which can also aid in the pathogen's prevention and source tracing (Ling et al, 2021, Fei et al, 2018, Fei et al, 2022. It is now believed that Cronobacter sakazakii is a newly discovered opportunistic bacteria that is frequently isolated from powdered milk infant formula and other foods that usually cause severe morbidity and mortality through some infectious diseases in neonates, infants, and other age groups, and so far, especially in Egypt, limited studies are available on its prevalence rate in foodstuff.…”