^-lactamasee Producing Bacteria in Adult Periodontitis S

t Inn 23 untreated adult periodontitis patients, the occurrence of Ö-lactamase producingg periodontal bacteria was determined. In addition to non-selective isolationn media, selective isolation and growth of ö-lactamase positive subgingival bacteriall species was carried out on blood agar plates supplemented with amoxicillinn and plates with amoxicillin + clavulanic acid. Porphyromonas gingivalis,lis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, PeptostreptococcusPeptostreptococcus micros, Fusobacterium nucleatum, Bacteroides forsythus andd Campylobacter rectus isolates from the non-selective medium were tested forr Ö-lactamase activity by a nitrocefin disk method (DrySlide®) and by a laboratoryy chromogenic nitrocefin-based test. Isolates from the amoxicillin plates that weree absent on the amoxicillin/clavulanic acid plates were identified and tested forr Ö-lactamase production. Based on the non-selective plates, 6 of 23 P. intermediamedia isolates, 2 of 19 B. forsythus isolates and 3 of 23 F. nucleatum isolates weree Ö-lactamase positive. The ö-lactamase positive species Prevotella loescheii,scheii, Prevotella buccae, Prevotella buccalis and Actinomyces spp were recoveredd from the selective amoxicillin plates. Ö-Lactamase positive subgingival speciess were recovered from 17 of 23 patients (74%) but usually comprised low proportionss of the subgingival microflora (range < 0.01-15%). Comparison of the DrySlide®® test and the nitrocefin-based laboratory test revealed full agreement of testt results. Ö-Lactamase activity in whole subgingival plaque was detected in 12 patientt samples (52%). It was concluded that ö-lactamase activity in subgingival bacteriaa in adult periodontitis is a common feature. However, since the majority off the samples showed only low-level enzymatic activity, the clinical relevance of thiss observation with regard to therapy with unprotected enzyme-susceptible Ölactamss is uncertain, though failure on the other hand, is difficult to rule out when aa mechanism of resistance is present. The majority of ö-lactamase positive strainss was found among species of the Prevotella genus.