Abstract：
Vibrio cholerae can form biofilms in the aquatic environment and in the human intestine, facilitating the release of hyper-infectious aggregates. Due to the increasing antibiotic resistance, alternatives need to be found. One of these alternatives is antimicrobial peptides, including polymyxin B (PmB). In this study, we first investigated the resistance of V. cholerae O1 El Tor strain A1552 to various antimicrobials under aerobic and anaerobic conditions. An increased resistance to PmB is observed in anaerobiosis, with a 3-fold increase in the dose required for 50 % growth inhibition. We then studied the impact of the PmB on the formation and the degradation of V. cholerae biofilms to PmB. Our results show that PmB affects more efficiently biofilm formation under anaerobic conditions. On the other hand, preformed biofilms are susceptible to degradation by PmB at concentrations close to the minimal inhibitory concentration. At higher concentrations, we observe an opacification of the biofilm structures within 20 min post-treatment, suggesting a densification of the structure. This densification does not seem to result from the overexpression of matrix genes but rather from DNA release through massive cell lysis, likely forming a protective shield that limits the penetration of the PmB into the biofilm.
摘要：
霍乱弧菌可以在水生环境和人体肠道中形成生物膜，促进高传染性聚集体的释放。由于抗生素耐药性的增加，需要找到替代品。这些替代品之一是抗菌肽，包括多粘菌素B（PmB）。在这项研究中,我们首先研究了霍乱弧菌O1ElTor菌株A1552在需氧和厌氧条件下对各种抗菌剂的抗性。在厌氧菌病中观察到对PmB的抗性增加，50%生长抑制所需的剂量增加3倍。然后，我们研究了PmB对霍乱弧菌生物膜形成和降解为PmB的影响。我们的结果表明，PmB在厌氧条件下更有效地影响生物膜的形成。另一方面,预先形成的生物膜在接近最小抑制浓度的浓度下容易被PmB降解。在较高浓度下,我们观察到处理后20分钟内生物膜结构的不透明，表明结构的致密化。这种致密化似乎不是由于基质基因的过度表达，而是由于大量细胞裂解导致的DNA释放。可能形成限制PmB渗透到生物膜中的保护罩。
