Prevalence, Genetic Diversity, and Antibiotic Resistance of Bacillus cereus Isolated from Korean Fermented Soybean Products

Abstract

Bacillus cereus contamination is a major food safety problem for Korean fermented soybean products, but few studies have assessed its potential to cause foodborne illness. The objectives of this study were to investigate the prevalence and characteristics of B. cereus isolated from Korean fermented soybean products. B. cereus was detected in 110 of 162 (67.9%) samples. The highest B. cereus frequency was observed in deonjang (68 of 93 samples, 73.1%) and cheonggukjang (18 of 25, 72.0%); however, nonhemolytic enterotoxin was detected only in 22 of 162 samples (13.6%). Although the tested B. cereus isolates showed diverse pulsotypes according to repetitive sequence-PCR banding patterns, they displayed similar antibiotic sensitivity spectra. The low frequency of enterotoxin detection suggests that the potential risk of B. cereus foodborne illness associated with Korean fermented soybean products is lower than generally presumed. However, considering the prevalence of B. cereus and the high content of fermented soybean products in the Korean diet, it is necessary to constantly monitor the level of contamination with B. cereus and its toxins in such Korean food products.

Genetic diversity, antimicrobial resistance, toxin gene profiles, and toxin production ability of Bacillus cereus isolates from doenjang, a Korean fermented soybean paste

“…In previous studies, the incidence ratios of B. cereus in doenjang samples varied considerably. As compared to the B. cereus detection rate in doenjang samples (52%) determined in this study, Kim et al (2015) reported that 73% of samples were contaminated with B. cereus from 93 doenjang samples, and Kim and Kim (2012) presented a much lower detection rate of 33.3% with contamination levels of 10 2 -10 5 cfu/g in doenjang samples. Yim et al (2015) also investigated 26 doenjang products and reported that 13 (50%) were contaminated with B. cereus.…”

“…Among the positive strains for NHE toxin, 83% (29 out of 35) produced high levels of the toxin (production at an index of 4). These proportions are relatively high compared to previous works which investigated NHE toxin production with the same kits in doenjang isolates (Kim et al, 2015) and foodrelated isolates (Chon, Kim, Lee, Hyeon, & Seo, 2012;Lee et al, 2012;Rahmati & Labbe, 2008). Of the 35 B. cereus isolates, 24 strains (69%) were negative for all 3 genes in the HBL complex (hblACD), and 8 isolates (23%) showed amplification products for 1 or 2 genes.…”

Detection, genetic diversity and antibiotic resistance profiles of Bacillus cereus isolated from sago processing plants in Malaysia

“…On the other hand, all isolates show the highest level of susceptibility towards imipenem (100%), norfloxazin (100%), tobramycin (96.67%). The results were in close agreement to a study by Andrews and Wise (2002), Park et al (2009) and Kim et al (2015). It is not surprising since imipenem could be prescribed by doctors as a treatment for bacterial infection (Letchumanan et al, 2015).…”

“…All isolates were highly resistance to ß-lactam antibiotics penicillin (100%), and ampicillin (100%). High penicillin and ampicillin resistant were also observed in B. cereus in fermented soybean (Kim et al, 2015). Andrews and Wise (2002) and Park et al (2009) also reported that B. cereus were highly resistant to penicillin and ampicillin.…”

A Study on Prevalence and Characterization of Bacillus cereus in Ready-to-Eat Foods in China

“…The sensitivity of B. cereus to 20 antimicrobial agents was tested using the standard Kirby-Bauer disk diffusion method (Park et al, 2009; The Clinical and Laboratory Standards Institute [CLSI], 2010; Kim et al, 2015;Gao et al, 2018;Osman et al, 2018;Yu et al, 2019). The B. cereus isolates were streaked on the nutrition agar plate and grown 16-18 h at 37 • C. The colony was then picked and suspended using 0.85% physiological saline to 0.5 McFarland standard and spread on the surface of a Mueller-Hinton agar plate.…”