College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China.
College of Food Science and Engineering, Northwest A&F University, Yangling, 712100, Shaanxi, China.
Anaerobe. 2022 Dec;78:102667. doi: 10.1016/j.anaerobe.2022.102667. Epub 2022 Oct 23.
Veillonella, known as early colonizers in oral biofilms, take part in some infections in human. Biofilm refers to complex, sessile communities of microbes, which function as strong barriers for bacteria to survive. Biofilm matrixes surrounding bacteria enable them to withstand harsh conditions, protect against immune cells, etc., and also make them resistant to antimicrobial treatments. Thus, the knowledge of antibiotic susceptibility and biofilm formation of Veillonella will shed light on their resistance mechanism.
Their morphology was observed by scanning electron microscopy (SEM). According to the performance standards for antibiotic susceptibility testing of the Clinical & Laboratory Standards Institute, the Agar dilution method was used to study the susceptibility of Veillonella strains to eight antibiotics (ampicillin, piperacillin-tazobactam, cefoxitin, tetracycline, moxifloxacin, clindamycin, metronidazole, and vancomycin). In addition, we applied the crystal violet staining method to reveal the processes of biofilm formation of these Veillonella strains.
V. rogosae, V. nakazawae, and V. parvula were isolated from oral cavities of healthy adults and V. ratti was isolated from dairy goat droppings. Observations by scanning electron microscopy showed that Veillonella were spherical and arranged in single or short chains. The diameter of a single cell was about 0.3-0.5 μm. The Minimum Inhibitory Concentrations (MICs) of the antibiotics were determined and the results showed that these four strains were all sensitive to cefoxitin, tetracycline, moxifloxacin, clindamycin and metronidazole. Among the four strains, V. ratti was resistant to piperacillin-tazobactam, and V. rogosae and V. nakazawae were resistant to ampicillin. The vancomycin susceptibility of the four Veillonella strains varied greatly. The MICs of vancomycin against V. rogosae and V. ratti were greater than 256 μg/mL but the MICs of vancomycin against V. nakazawae and V. parvula were less than 2 μg/mL. V. parvula had significantly higher biofilm-forming ability than the other three strains (p < 0.05) and V. nakazawae had the weakest biofilm-forming ability.
In this study, V. rogosae, V. nakazawae, V. parvula and V. ratti were isolated and identified. The four strains of Veillonella showed differences in MIC values for different antibiotics and biofilm-forming ability.
韦荣氏球菌属（Veillonella）作为口腔生物膜中的早期定植菌，参与了人类的一些感染。生物膜是指微生物的复杂、固着群落，其功能是作为细菌存活的强大屏障。细菌周围的生物膜基质使它们能够耐受恶劣的环境条件，抵御免疫细胞等，并且使它们能够抵抗抗菌药物治疗。因此，了解韦荣氏球菌属对抗生素的敏感性和生物膜形成将揭示其耐药机制。
通过扫描电子显微镜（SEM）观察它们的形态。根据临床和实验室标准协会（Clinical & Laboratory Standards Institute）的抗生素药敏试验性能标准，采用琼脂稀释法研究韦荣氏球菌属菌株对 8 种抗生素（氨苄西林、哌拉西林-他唑巴坦、头孢西丁、四环素、莫西沙星、克林霉素、甲硝唑和万古霉素）的敏感性。此外，我们应用结晶紫染色法揭示这些韦荣氏球菌属菌株的生物膜形成过程。
从健康成年人的口腔中分离出韦荣氏球菌（V. rogosa）、中间韦荣氏球菌（V. nakazawae）和小韦荣氏球菌（V. parvula），从乳山羊粪便中分离出拉氏韦荣氏球菌（V. ratti）。扫描电子显微镜观察显示，韦荣氏球菌呈球形，呈单链或短链排列。单个细胞的直径约为 0.3-0.5μm。确定了抗生素的最小抑菌浓度（MICs），结果表明，这四种菌株对头孢西丁、四环素、莫西沙星、克林霉素和甲硝唑均敏感。在这四种菌株中，拉氏韦荣氏球菌（V. ratti）对哌拉西林-他唑巴坦耐药，而罗格斯韦荣氏球菌（V. rogosa）和中间韦荣氏球菌（V. nakazawae）对氨苄西林耐药。四种韦荣氏球菌属菌株对万古霉素的敏感性差异很大。万古霉素对罗格斯韦荣氏球菌（V. rogosa）和拉氏韦荣氏球菌（V. ratti）的 MIC 值均大于 256μg/mL，但万古霉素对中间韦荣氏球菌（V. nakazawae）和小韦荣氏球菌（V. parvula）的 MIC 值均小于 2μg/mL。小韦荣氏球菌（V. parvula）的生物膜形成能力明显高于其他三种菌株（p<0.05），而中间韦荣氏球菌（V. nakazawae）的生物膜形成能力最弱。
本研究分离并鉴定了罗格斯韦荣氏球菌（V. rogosa）、中间韦荣氏球菌（V. nakazawae）、小韦荣氏球菌（V. parvula）和拉氏韦荣氏球菌（V. ratti）。四种韦荣氏球菌属菌株对不同抗生素的 MIC 值和生物膜形成能力存在差异。
