Apple cider vinegar exhibits promising antibiofilm activity against multidrug-resistant Bacillus cereus isolated from meat and their products

Abstract

Background: Bacillus cereus (B. cereus) biofilm is grown not only on medical devices but also on different substrata and is considered a potential hazard in the food industry. Quorum sensing (QS) plays a serious role in the synthesis of biofilm with its surrounding extracellular matrix enabling irreversible connection of the bacteria. Aim: The present study directed to determine the prevalence, antimicrobial resistance patterns, and biofilm formation ability of B. cereus in meat and meat products in Egypt. Methods: A total of one hundred and fifty meat and meat product samples were included in this study. The samples were transferred to the Bacteriology Laboratory for further bacteriological examination. Thereafter, the antimicrobial, antiquorum sensing and antibiofilm potential of apple cider vinegar (ACV) on B. cereus were evaluated. Results: Thirty four samples out of 150 samples (22.67%) were positive for B. cereus. Antimicrobial susceptibility testing revealed that all B. cereus isolates were resistant to ampicillin and colistin however none of them were resistant to ciprofloxacin and imipenem. All multidrug resistant (MDR) B. cereus isolates (n = 12) could produce biofilms with varying degrees; among them, 6 (50%), 3 (25%) and 3 (25%) isolates were weak, moderate and strong biofilm producers, respectively. Interestingly, the ACV exhibited marked inhibitory activities against B. cereus isolates with minimum inhibitory concentrations (MIC) ranging from 2 to 8 μg/mL. Moreover, it showed a good antibiofilm activity (> 50% reduction of biofilm formation) after exposure of biofilm producing B. cereus isolates to the minimum biofilm inhibitory concentrations 50 (MBIC50) of 4 μg/mL. Reverse transcriptase quantitative polymerase chain reaction (RT-qPCR) revealed down-regulation of biofilm genes (tasA and sipW) and their regulator (plcR) in strong biofilm producers in comparison to those of the control. Conclusion: Our study is the first report, which spotlight on the ACV activity against B. cereus biofilm and its consequence as a strong antibacterial and antibiofilm agent in food industry and human health risk.