Departamento de Medicina Veterinária Preventiva, Centro de Ciências Rurais, Programa de Pós-graduação em Medicina Veterinária, Universidade Federal de Santa Maria, Santa Maria, Brazil.
Universidade Federal do Vale do São Francisco, Petrolina, Brazil.
J Appl Microbiol. 2019 Feb;126(2):369-376. doi: 10.1111/jam.14086. Epub 2018 Nov 22.
This study aimed to verify the formation of biofilms by Moraxella bovis, Moraxella ovis and Moraxella bovoculi isolates from ruminants. In addition, the lysozyme activity against the isolates of M. bovis, M. ovis and M. bovoculi in free form and in biofilms was determined.
In this study, 54 isolates of Moraxella sp. obtained from bovine and ovine clinical samples were evaluated in vitro for capacity of biofilm formation and lysozyme susceptibility in planktonic and sessile cells. In addition, biofilms produced by four Moraxella sp. isolates were visualized under scanning electron microscope (SEM). It was possible to demonstrate, for the first time, the ability to form biofilms by M. ovis and M. bovoculi. The isolates of Moraxella sp. have the capacity to form biofilms in different intensities, varying among weak, moderate and strong. It was verified that the lysozyme shows activity on Moraxella sp. in planktonic form. However, on biofilms there was a reduction in the production, but without impairing its formation, and on consolidated biofilms the lysozyme did not have the capacity to eradicate the preformed biofilms.
This work shows the capacity of biofilm formation by Moraxella sp. of veterinary importance. The lysozyme susceptibility of Moraxella sp. in planktonic form shows that this enzyme has bacteriostatic activity on this micro-organism and it reduced the production of biofilms.
Based on the results, it is possible to infer that the biofilm formation capacity by Moraxella sp. and the resistance to lysozyme concentrations equal to or greater than the physiological levels of the ruminant tear may be linked not only to the capacity to colonize the conjunctiva, but also to remain in this place even after healing of the lesions, being a reservoir of Moraxella sp. in a herd.
本研究旨在验证从反刍动物分离的莫拉氏菌属牛种、羊种和牛亚种生物膜的形成，并测定游离态和生物膜态下溶菌酶对分离株莫拉氏菌属牛种、羊种和牛亚种的活性。
本研究中，评估了从牛和羊临床样本中获得的 54 株莫拉氏菌属分离株在体外形成生物膜的能力以及浮游和贴壁细胞中溶菌酶的敏感性。此外，用扫描电子显微镜（SEM）观察了 4 株莫拉氏菌属分离株产生的生物膜。首次证明了羊种莫拉氏菌和牛亚种莫拉氏菌形成生物膜的能力。莫拉氏菌属分离株的生物膜形成能力存在差异，从弱到中等到强。证实了溶菌酶对浮游形式的莫拉氏菌属具有活性。然而，在生物膜上，其产量减少，但不影响其形成，而在已形成的生物膜上，溶菌酶没有能力根除预先形成的生物膜。
本研究表明兽医重要的莫拉氏菌属具有形成生物膜的能力。浮游形式的莫拉氏菌属对溶菌酶的敏感性表明，该酶对该微生物具有抑菌活性，并减少生物膜的形成。
根据结果可以推断，莫拉氏菌属的生物膜形成能力和对等于或大于反刍动物泪液生理水平的溶菌酶浓度的抗性，不仅与定植结膜的能力有关，而且在病变愈合后仍能在该部位存活，成为畜群中莫拉氏菌属的储库。
