Vinod Kumar Kirubakaran, Lall Chandan, Vimal Raj Ratchagadasse, Vedhagiri Kumaresan, Sunish Ittoop Pulikkottil, Vijayachari Paluru
1 Regional Medical Research Centre (ICMR), WHO Collaborating Centre for Diagnosis, Reference, Research and Training in Leptospirosis , Port Blair, Andaman and Nicobar Islands, India .
2 DPT-cGMP Facility, Central Research Institute , Ministry of Health & Family Welfare, Kasauli, Himachal Pradesh, India .
Microb Drug Resist. 2018 Sep;24(7):1040-1042. doi: 10.1089/mdr.2017.0409. Epub 2018 Apr 20.
Antibiotics at subminimal inhibitory concentrations (sub-MICs) are known to induce biofilm formation in numerous bacteria in vitro. In this report, the effect of sub-MIC levels of antibiotics (doxycycline and tetracycline) on biofilm formation by leptospiral reference strains and isolates was investigated. The sub-MIC levels of both tetracycline and doxycycline were able to induce biofilm in some of the leptospiral strains. This is the first report demonstrating the effect of sub-MIC level of antibiotics in inducing biofilm formation in Leptospira. The induction of biofilm may solely be a response to the amount of threshold stress enforced by low levels of antibiotics. The mechanism of biofilm induction by subinhibitory antibiotic concentrations needs to be explored further. Studies are required to understand the clinical relevance of the phenomenon and its contribution to biofilm formation in the host, resulting in the failure of antimicrobial therapy during the treatment of chronic leptospirosis.
已知亚最小抑菌浓度（亚 MIC）的抗生素在体外可诱导多种细菌形成生物膜。在本报告中，研究了抗生素（强力霉素和四环素）的亚 MIC 水平对钩端螺旋体参考菌株和分离株形成生物膜的影响。四环素和强力霉素的亚 MIC 水平均能在一些钩端螺旋体菌株中诱导生物膜形成。这是首次报道抗生素亚 MIC 水平对钩端螺旋体诱导生物膜形成的影响。生物膜的诱导可能仅仅是对低水平抗生素所施加的阈值应激量的一种反应。亚抑制性抗生素浓度诱导生物膜形成的机制需要进一步探索。需要开展研究以了解该现象的临床相关性及其对宿主体内生物膜形成的作用，从而导致慢性钩端螺旋体病治疗期间抗菌治疗失败。
