Microbiology Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, 474002, India.
Electron Microscopy Division, Defence Research and Development Establishment, Jhansi Road, Gwalior, 474002, India.
J Antimicrob Chemother. 2018 Jul 1;73(7):1841-1847. doi: 10.1093/jac/dky127.
Vibrio cholerae, the aetiological agent of the deadly diarrhoeal disease cholera, is known to form biofilm. The antibiotic susceptibility status of biofilm of V. cholerae O139, an important epidemic strain in India and other countries, has not previously been studied in detail.
Antibiotic susceptibility status of planktonic and biofilm cultures of V. cholerae O139 was evaluated by determining MIC, MBC and minimum biofilm eradication concentration (MBEC) values of five different classes of antibiotics using established methods. Effects of antibiotic treatment on planktonic and biofilm cultures were analysed by scanning electron microscopy. The virulence of the antibiotic-surviving population (ASP) was evaluated using an infant mouse model. The frequency of spontaneous mutants and inheritability of antibiotic resistance were determined with standard methods.
The antibiotic resistance exhibited by biofilm of V. cholerae O139 was found to be significantly higher (P < 0.05) than its planktonic counterpart. The biofilm-associated antibiotic resistance was found to be transient and exclusive to the biofilm culture. The frequency of ASP clones among antibiotic-treated biofilm cultures occurred at a rate of 0.012%-0.95% and these clones were found to retain the virulence and antibiotic resistance of their parent strains.
The biofilm of V. cholerae O139 was found to be resistant to different types of antibiotics tested. This unconventional biofilm resistance highlights the hidden danger of antimicrobial escape by V. cholerae, increased risk of cholera transmission and its continued persistence in the environment.
霍乱弧菌是致命腹泻病霍乱的病原体，已知其能够形成生物膜。然而，此前尚未详细研究印度和其他国家流行的 O139 血清型霍乱弧菌生物膜的抗生素药敏状态。
采用建立的方法，测定 5 种不同类别的抗生素对 O139 型霍乱弧菌浮游和生物膜培养物的 MIC、MBC 和最小生物膜清除浓度（MBEC）值，评估浮游和生物膜培养物的抗生素药敏状态。通过扫描电子显微镜分析抗生素处理对浮游和生物膜培养物的影响。采用婴儿鼠模型评估抗生素存活群体（ASP）的毒力。采用标准方法测定自发突变体的频率和抗生素耐药性的遗传性。
发现 O139 型霍乱弧菌生物膜的抗生素耐药性明显高于浮游细胞（P<0.05）。生物膜相关的抗生素耐药性是暂时的，仅存在于生物膜培养物中。在抗生素处理的生物膜培养物中，ASP 克隆的频率为 0.012%-0.95%，这些克隆保留了其亲本菌株的毒力和抗生素耐药性。
O139 型霍乱弧菌的生物膜对测试的不同类型抗生素具有耐药性。这种非传统的生物膜耐药性突显了霍乱弧菌逃避抗菌药物的潜在危险，增加了霍乱传播的风险及其在环境中的持续存在。
