Haakensen Monique, Vickers David M, Ziola Barry
Department of Pathology and Laboratory Medicine, Room 2841 Royal University Hospital, 103 Hospital Drive, University of Saskatchewan, Saskatoon, SK S7N 0W8, Canada.
BMC Microbiol. 2009 Sep 7;9:190. doi: 10.1186/1471-2180-9-190.
Though important in the context of food microbiology and as potential pathogens in immuno-compromised humans, bacterial isolates belonging to the genus Pediococcus are best known for their association with contamination of ethanol fermentation processes (beer, wine, or fuel ethanol). Use of antimicrobial compounds (e.g., hop-compounds, Penicillin) by some industries to combat Pediococcus contaminants is long-standing, yet knowledge about the resistance of pediococci to antimicrobial agents is minimal. Here we examined Pediococcus isolates to determine whether antibiotic resistance is associated with resistance to hops, presence of genes known to correlate with beer spoilage, or with ability to grow in beer.
Lactic acid bacteria susceptibility test broth medium (LSM) used in combination with commercially available GPN3F antimicrobial susceptibility plates was an effective method for assessing antimicrobial susceptibility of Pediococcus isolates. We report the finding of Vancomycin-susceptible Pediococcus isolates from four species. Interestingly, we found that hop-resistant, beer-spoilage, and beer-spoilage gene-harbouring isolates had a tendency to be more susceptible, rather than more resistant, to antimicrobial compounds.
Our findings indicate that the mechanisms involved in conferring hop-resistance or ability to spoil beer by Pediococcus isolates are not associated with resistance to antibiotics commonly used for treatment of human infections. Also, Vancomycin-resistance was found to be isolate-specific and not intrinsic to the genus as previously believed.
虽然在食品微生物学背景下以及作为免疫功能低下人群的潜在病原体很重要，但属于片球菌属的细菌分离株最为人所知的是它们与乙醇发酵过程（啤酒、葡萄酒或燃料乙醇）的污染有关。一些行业使用抗菌化合物（如啤酒花化合物、青霉素）来对抗片球菌污染物由来已久，但关于片球菌对抗菌剂的耐药性的知识却很少。在这里，我们检测了片球菌分离株，以确定抗生素耐药性是否与对啤酒花的抗性、已知与啤酒变质相关的基因的存在或在啤酒中的生长能力有关。
将乳酸菌药敏试验肉汤培养基（LSM）与市售的GPN3F药敏平板结合使用是评估片球菌分离株药敏性的有效方法。我们报告了从四个物种中分离出对万古霉素敏感的片球菌。有趣的是，我们发现对啤酒花有抗性、导致啤酒变质以及携带啤酒变质基因的分离株往往对抗菌化合物更敏感，而不是更耐药。
我们的研究结果表明，片球菌分离株产生啤酒花抗性或导致啤酒变质的机制与对常用于治疗人类感染的抗生素的耐药性无关。此外，发现万古霉素耐药性是分离株特异性的，而不是如先前认为的那样是该属固有的。
