Antibiotic susceptibility of putative periodontal pathogens in advanced periodontitis patients

Abstract

In the present study, the antibiotic susceptibility of most prevalent micro-organisms in advanced periodontitis patients was evaluated. In 56 patients, pooled subgingival plaque samples were taken from the deepest site of each quadrant and were cultivated anaerobically. From each patient, the 4 most frequently encountered types of bacterial colonies were subcultured and identified (Rapid ID 32 A). From all bacterial species identified in the 224 subcultures, the 4 most prevalent were used for susceptibility testing to tetracycline, metronidazole and amoxicillin/clavulanate using the E Test. The most prevalent microorganisms were Fusobacterium nucleatum (38/214), Peptostreptococcus micros (33/214), Prevotella oralis (33/214) and Porphyromonas gingivalis (32/214). Regarding antibiotic susceptibility it could be shown that minimal inhibitory concentration (MIC) in all cases was below antibiotic concentrations achievable in gingival crevicular fluid. However, antibiotic resistance was seen in 3 to 29% of the investigated microorganisms.

Antibiotic resistance of subgingival species during and after antibiotic therapy

“…Other investigations have also shown that anaerobic species such as P. intermedia, P. gingivalis and Fusobacterium species are highly sensitive to metronidazole (Eick et al 1999, Kleinfelder et al 1999, Poulet et al 1999). On the other hand, metronidazole-resistant strains of B. forsythus and P. gingivalis were not detected in any plaque or saliva sample before, during or after therapy.…”

Validation of Antibiotic Efficacy on In Vitro Subgingival Biofilms

“…Earlier studies have used either bacteria in planktonic culture or single‐species biofilms to test the in vitro efficacy of various antibiotics. MICs for several single species isolated from subgingival plaque, including P. gingivalis and F. nucleatum , are shown to be below antibiotic concentrations achievable in GCF 13 . In terms of single‐species biofilms, one of the most studied has been P. gingivalis , which is shown to be susceptible to amoxicillin, doxycycline, and metronidazole over a period of 48 hours, albeit at higher MICs than in conventional planktonic cultures 19,20 .…”

“…The minimum inhibitory concentration (MIC) for a number of putative periodontal pathogens is shown to be below the antibiotic concentrations achievable in GCF 13 . Nevertheless, studies on the efficacy of antibiotics have traditionally used planktonic bacterial cultures of periodontal pathogens, and in many cases, at concentrations that are not of physiologic relevance.…”

Improved drug delivery properties of PVDF membranes functionalized with β‐cyclodextrin—Application to guided tissue regeneration in periodontology

“…The MIC 90 for Actinobacillus actinomycetemcomitans is of 3.1 g/mL. 31 To limit the development of bacterial resistance, Kleinfelder et al 32 proposed that the quantity of released antibiotic should be 100 times that of the MIC to induce a relevant clinical effect. The quantity delivered in the present experimental conditions seems to be compatible with these prescriptions as the volume in which the membrane has to release the antibiotic does not exceed 1 mL.…”