Journal Article

Antibiotics resistance and toxin profiles of Bacillus cereus-group isolates from fresh vegetables from German retail markets

Schneider, Carmen, Becker, Biserka, Huch, Melanie, Stoll, Dominic A., Franz, Charles M. A. P., Cho, Gyu-Sung, Kabisch, Jan, Igbinosa, Etinosa O., Brinks, Erik, Fiedler, Gregor

2019

Overview

Background This study aimed to evaluate the safety of raw vegetable products present on the German market regarding toxin-producing Bacillus cereus sensu lato ( s.l. ) group bacteria. Results A total of 147 B. cereus s.l. group strains isolated from cucumbers, carrots, herbs, salad leaves and ready-to-eat mixed salad leaves were analyzed. Their toxinogenic potential was assessed by multiplex PCR targeting the hemolysin BL ( hbl ) component D ( hblD ), non-hemolytic enterotoxin ( nhe ) component A ( nheA ), cytotoxin K-2 ( cytK-2 ) and the cereulide ( ces ) toxin genes. In addition, a serological test was used to detect Hbl and Nhe toxins. On the basis of PCR and serological results, none of the strains were positive for the cereulide protein/genes, while 91.2, 83.0 and 37.4% were positive for the Hbl, Nhe and CytK toxins or their genes, respectively. Numerous strains produced multiple toxins. Generally, strains showed resistance against the β-lactam antibiotics such as penicillin G and cefotaxim (100%), as well as amoxicillin/clavulanic acid combination and ampicillin (99.3%). Most strains were susceptible to ciprofloxacin (99.3%), chloramphenicol (98.6%), amikacin (98.0%), imipenem (93.9%), erythromycin (91.8%), gentamicin (88.4%), tetracycline (76.2%) and trimethoprim/sulfamethoxazole combination (52.4%). The genomes of eight selected strains were sequenced. The toxin gene profiles detected by PCR and serological test mostly agreed with those from whole-genome sequence data. Conclusions Our study showed that B. cereus s.l. strains encoding toxin genes occur in products sold on the German market and that these may pose a health risk to the consumer if present at elevated levels. Furthermore, a small percentage of these strains harbor antibiotic resistance genes. The presence of these bacteria in fresh produce should, therefore, be monitored to guarantee their safety.

• Publisher: BioMed Central,BioMed Central Ltd,Springer Nature B.V,BMC
• Subject: Amides / Amikacin / Aminoglycosides / Amoxicillin / Ampicillin / Antibacterial agents / Antibiotic resistance / Antibiotics / Bacillus cereus / Bacillus cereus sensu lato / Bacteria / Beta lactam antibiotics / Beta lactamases / Biological Microscopy / Biomedical and Life Sciences / Carrots / Cereulide / Chloramphenicol / Chloromycetin / Ciprofloxacin / Clavulanic acid / Cloxacillin / Consent / Convenience foods / Cucumbers / DNA sequencing / Drug resistance / Erythromycin / Food safety / Fresh produce / Gene amplification / Genes / Genetic research / Genomes / Genomics / Gentamicin / Health aspects / Health risks / Imipenem / Lactams / Leaves / Life Sciences / Microbe-host interactions and microbial pathogenicity / Microbial drug resistance / Microbiology / Mycology / Nucleotide sequence / Parasitology / Penicillin / Penicillin G / Penicillins / Peptides / Pharmaceutical industry / Product safety / Research Article / Strains (organisms) / Studies / Sulfamethoxazole / Tetracyclines / Toxins / Trimethoprim / Vegetables / Virology / Whole genome sequencing / β-Lactam antibiotics