Prevalence, Genetic Diversity, and Antibiotic Susceptibility of Bacillus cereus Strains Isolated from Rice and Cereals Collected in Korea

Abstract

Incidence and properties of Bacillus cereus strains naturally present in cereals were evaluated by phenotypic characterization, antibiotic susceptibility testing, and pulsed-field gel electrophoresis. Of 293 cereal samples tested, 73 (25%) contained B. cereus strains. Incidence of B. cereus isolates varied with respect to sample; they were found in 15 (37%) of 83 brown rice samples, 23 (37%) of 63 glutinous rice samples, 16 (21%) of 76 barley samples, and 19 (27%) of 71 Job's tears samples. All B. cereus isolates from cereals were positive for diarrheal toxin genes. The isolates were susceptible to most of the antibiotics tested, but they were highly resistant to ampicillin, cefepime, oxacillin, and penicillin. Of the genes assayed by the PCR technique, a high frequency of nheA (99%) and hblDC (84%) was found in the genomic DNA of cereal-associated isolates, whereas cytK was less common (55%). From the strains carrying the hblDC genes, 93% produced enterotoxin HBL. B. cereus isolates did not have significant genetic homology. The genetic diversity and toxic potential differ among the strains isolated from cereals. These results provide important information on toxin gene profiles of cereal-associated B. cereus for population studies.

Prevalence, antibiotic-resistance properties and enterotoxin gene profile of <i>Bacillus cereus</i> strains isolated from milk-based baby foods

“…Tewari et al [24] reported that B. cereus strains harbored a high prevalence of resistance against carbenicillin, kanamycin and ampicillin which was similar with our findings. They showed that all isolates were resistant to bacitracin and penicillin G. Similar findings have been reported by Park et al [25]. Enayat et al [26] reported that B. cereus strains of foods with animal origins harbored the highest levels of resistance against ampicillin, tetracycline and trimethoprimsulfamethoxazole which was similar to our findings.…”

Incidence, Intraspecific Diversity and Toxigenic Profile of <i>Bacillus cereus</i> in the Yellow-Water, a Fermented Food Flavor Enhancer

“…52% of isolates possessed complete set hbl genes and 36% of isolates have only one or two of hblA, hblC and hblD gene (Table 3). In general, the percentage of hbl positives in this study (88%) is consistent with previous works that reported 84 _ 92% of incidence in food related B. cereus isolates (Park et al, 2009;Kim et al, 2011;Chon et al, 2012). The cytK and entFM were 46% and 70% of prevalence in the Yellow-Water, respectively.…”

Isolation of Bacillus cereus Group from the Fecal Material of Endangered Wood Turtles

“…In other studies, this gene has also been found to be the most frequent toxin gene present [6,9,20,26,27,33]. Nhe genes are believed to be the most common enterotoxin genes [23].…”