Bernardi, Sara and Anderson, Annette and Macchiarelli, Guido and Hellwig, Elmar and Cieplik, Fabian and Vach, Kirstin and Al-Ahmad, Ali (2021) Subinhibitory Antibiotic Concentrations Enhance Biofilm Formation of Clinical Enterococcus faecalis Isolates. ANTIBIOTICS-BASEL, 10 (7): 874. ISSN 2079-6382,
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Enterococcus faecalis 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 E. faecalis 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 E. faecalis 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.
| Item Type: | Article |
|---|---|
| Uncontrolled Keywords: | RESISTANCE; biofilms; subinhibitory antibiotic concentrations; Enterococcus faecalis |
| Subjects: | 600 Technology > 610 Medical sciences Medicine |
| Divisions: | Medicine > Lehrstuhl für Zahnerhaltung und Parodontologie |
| Depositing User: | Dr. Gernot Deinzer |
| Date Deposited: | 16 Sep 2022 08:37 |
| Last Modified: | 16 Sep 2022 08:37 |
| URI: | https://pred.uni-regensburg.de/id/eprint/47529 |
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