Antibiotic resistance of specific microorganisms after alveolar ridge reconstruction

Introduction: The aim of this preliminary study was to determinate of phenotypic resistance to antibiotics of experimental monospecific biofilms isolated from infections area in the mouth, from consecutive poor alveolar ridge reconstruction with bone addition.
Methods: Clinical and microbiological study was conducted on 4 strains of Pseudomonas aeruginosa and 4 strains Staphylococcus aureus, isolated from infectious processes, after alveolar ridge reconstruction, from 15 patients in the period of 4 years (2007-2010). The experimental model was developed for determining antibiotic sensitivity of bacterial cells included in biofilms. Namely, model development of biofilms in 96-well plates of plastic, crystal violet staining and reading absorbancin. The used antibiotics were: Colistin for the cases with Ps. aeruginosa, and Gentamicin for the cases with S. aureus.
Results: P. aeruginosa biofilm formation on plastic with presence of Colistin has been observed that microbial biofilms formed in the presence of various concentrations of antibiotic, the cells are similar in number and relatively stable, unlike the biofilms developed in the absence of antibiotic which has a maximum number of cells at 48h, after which cell number drops sharply. S. aureus biofilm formation in plastic wells with Gentamicin, results were similar developments were seen in the relatively constant at different times of the biofilm in the presence of antibiotic, irrespective of concentration.
Conclusions: Results obtained by using experimental model demonstrated that the antibiotic exerts a selective pressure on cells included in the biofilm, preventing the attainment of high cell densities, which would hasten ripening and decay that microbial biofilms. Therefore, antibiotics regardless of concentration, favoried the maintenance of early biofilms and their persistence over long periods of time in the body.