Bernardi Sara, Anderson Annette, Macchiarelli Guido, Hellwig Elmar, Cieplik Fabian, Vach Kirstin, Al-Ahmad Ali
Department of Life, Health and Environmental Sciences, University of L'Aquila, 67100 L'Aquila, Italy.
Centre of Microscopy, University of L'Aquila, 67100 L'Aquila, Italy.
Antibiotics (Basel). 2021 Jul 19;10(7):874. doi: 10.3390/antibiotics10070874.
is a microorganism that can be found in the oral cavity, especially in secondary endodontic infections, with a prevalence ranging from 24-70%. The increase in the ability to form biofilms in the presence of subinhibitory antibiotic concentrations is a phenomenon that is observed for a wide variety of bacterial pathogens and is associated with increased resistance. In this study, therefore, six isolates from an endodontic environment and two control strains were exposed to subinhibitory concentrations of Penicillin G, Amoxicillin, Doxycycline, Fosfomycin, Tetracycline and Vancomycin and examined for their biofilm formation abilities. The minimum inhibitory concentration (MIC) was determined for all isolates. A culture of the isolate was mixed with a serial dilution series of the respective antibiotic, incubated overnight and the biofilm formation was analyzed using a microtiter plate assay. All isolates were able to form biofilms in the absence of an antibiotic. A significant increase in biofilm formation of up to more than 50% was found in the isolates exposed to subinhibitory concentrations of various antibiotics. Most isolates showed a significant increase in Fosfomycin (7/8), Doxycycline (6/8) and Tetracycline (6/8). Three endodontic isolates showed a significant increase in five of the antibiotics examined at the same time. On exposure to Vancomycin, three endodontic isolates and the two control strains showed an increase. The increase in the ability to form biofilms extended over a concentration range from 1/2 to 1/64 of the MIC concentration. Antibiotics may reach certain niches in the oral cavity at subinhibitory concentrations only. This can increase the biofilm formation by enterococci, and in turn lead to decreased susceptibility of these taxa to antibiotics.
是一种可在口腔中发现的微生物，尤其是在继发性牙髓感染中，其患病率在24%至70%之间。在亚抑菌浓度的抗生素存在下生物膜形成能力的增加是多种细菌病原体中观察到的一种现象，并且与耐药性增加有关。因此，在本研究中，将来自牙髓环境的六个分离株和两个对照菌株暴露于亚抑菌浓度的青霉素G、阿莫西林、强力霉素、磷霉素、四环素和万古霉素，并检测它们的生物膜形成能力。测定了所有分离株的最低抑菌浓度（MIC）。将分离株的培养物与相应抗生素的系列稀释液混合，过夜培养，并使用微量滴定板分析法分析生物膜形成情况。所有分离株在无抗生素的情况下都能够形成生物膜。在暴露于亚抑菌浓度各种抗生素的分离株中发现生物膜形成显著增加高达50%以上。大多数分离株在磷霉素（7/8）、强力霉素（6/8）和四环素（6/8）作用下显示出显著增加。三个牙髓分离株在同时检测的五种抗生素作用下显示出显著增加。在暴露于万古霉素时，三个牙髓分离株和两个对照菌株显示增加。生物膜形成能力的增加在MIC浓度的1/2至1/64的浓度范围内。抗生素可能仅以亚抑菌浓度到达口腔中的某些生态位。这会增加肠球菌的生物膜形成，进而导致这些分类群对抗生素的敏感性降低。
