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In vitro minocycline activity on superinfecting microorganisms isolated from chronic periodontitis patients
Luciana Fernandes de Oliveira1, Antonio Olavo Cardoso Jorge, Silvana Soléo Ferreira Dos Santos
1University of Taubaté.
Abstract:
Chronic periodontitis is the most common type of periodontitis and it is associated with various species of microorganisms. Enteric rods, Pseudomonas, Staphyloccocus and Candida have been retrieved from periodontal pockets of patients with chronic periodontitis and correlated to cases of superinfection. Local or systemic antibiotic therapy is indicated to reinforce the effects of the conventional mechanical therapy. Minocycline has been suggested as one of the most effective drugs against periodontal pathogens. The aim of this work was to evaluate the minimal inhibitory concentration (MIC) of minocycline on superinfecting microorganisms isolated from the periodontal pocket and the oral cavity of individuals with chronic periodontitis. Isolates of Enterobacteriaceae (n = 25), Staphylococcus spp. (n = 25), Pseudomonas aeruginosa (n = 9) and Candida spp. (n = 25) were included in the study. Minimal inhibitory concentrations (MIC) of minocycline were determined using the Müeller-Hinton agar dilution method. Staphylococcus spp. isolates were the most sensitive to minocycline with a MIC of 8 microg/mL, followed by Enterobacteriaceae with a MIC of 16 microg/mL. The concentration of 16 microg/mL inhibited 96% of Candida spp. isolates. The MIC for 88.8% of the isolates of Pseudomonas aeruginosa was 128 microg/mL. A concentration of 1,000 microg/mL was not enough to inhibit 100% of the tested isolates.
Insights
Minocycline effectively inhibits common periodontal pathogens like Staphylococcus and Enterobacteriaceae at low concentrations. However, higher concentrations are needed for Candida and Pseudomonas aeruginosa, with some strains remaining resistant even at 1,000 microg/mL.
Area of Science:
- Microbiology
- Periodontology
- Pharmacology
Background:
- Chronic periodontitis involves diverse microorganisms, including enteric rods, Pseudomonas, Staphylococcus, and Candida, often leading to superinfections.
- Antibiotic therapy, particularly minocycline, is considered for managing periodontal pathogens alongside mechanical treatments.
Purpose of the Study:
- To determine the minimal inhibitory concentration (MIC) of minocycline against microorganisms commonly found in chronic periodontitis superinfections.
- To assess minocycline's efficacy against Enterobacteriaceae, Staphylococcus spp., Pseudomonas aeruginosa, and Candida spp. isolated from periodontal pockets.
Main Methods:
- The study utilized the Müeller-Hinton agar dilution method to determine MIC values.
- Microorganisms tested included 25 Enterobacteriaceae, 25 Staphylococcus spp., 9 Pseudomonas aeruginosa, and 25 Candida spp. isolates.
Main Results:
- Staphylococcus spp. showed the highest sensitivity to minocycline (MIC = 8 microg/mL).
- Enterobacteriaceae were inhibited at 16 microg/mL, and 96% of Candida spp. were inhibited at the same concentration.
- Pseudomonas aeruginosa exhibited higher resistance, with 88.8% inhibited at 128 microg/mL, and 1,000 microg/mL failed to inhibit all isolates.
Conclusions:
- Minocycline demonstrates variable efficacy against different microbial species associated with chronic periodontitis.
- Effective treatment of superinfections may require tailored antibiotic strategies due to observed resistance patterns, especially in Pseudomonas aeruginosa and Candida spp.
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