Molecular and phenotypical characterization of Cronobacter species isolated with high occurrence from oats and linseeds

Abstract

The aim of this study was to determine the prevalence Cronobacter from 30 samples of oats and 30 of linseeds commercially available in Brazil. The detection of Cronobacter was as according to the ISO 22964:2017. The isolates were characterized according to their phenotypically using Vitek 2.0 and antibiotic susceptibility profile. Molecular characterization was accomplished by real-time PCR targeting dnaG gene, PCR targeting rpoB gene, multiplex-PCR targeting cgcA gene, and fusA allele sequencing. Thirty-four samples (56.7%) contained Cronobacter; 19 (63.3%) of linseeds and 15 (50.0%) of oats. The isolates were identified as C. sakazakii (n = 18, 52.9%), C. dublinensis (n = 7, 20.6%), C. turicensis (n = 6, 17.7%), and C. malonaticus (n = 3, 8.8%). Thirty-four Cronobacter isolates were assigned to 11 different fusA alleles of which three were new (169, 170, and 171). The PCR targeting rpoB gene and cgcA gene failed to identify 19 isolates. Seven (20.6%) strains showed resistance or intermediate/resistance to tetracycline, and one (2.9%) strain had intermediate resistance to piperacilin-tazobactam. The presence of Cronobacter in oats and linseeds indicate that these foods can be a potential threat to human health, particularly when preparing food for elderly or immunosuppressed persons. The incorrect use of this foods for feeding of neonates (<six months) by careers should also be avoided.

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