Enterococci are potential pathogens in many human body sites. This study determined the subgingival occurrence and the in vitro antimicrobial susceptibility of enterococci in 100 persons with early-onset periodontitis and 545 persons with advanced adult periodontitis. Subgingival microbial samples were collected with paper points, transported in VMGA III and plated onto anaerobic enriched brucella blood agar or selective Enterococcosel agar (BBL Microbiology Systems). Enterococcal speciation was performed using commercial micromethod kit systems. In vitro sensitivity was determined using a commercial kit system and an agar dilution assay. Subgingival enterococci occurred in 1% of early-onset periodontitis patients and in approximately 5% of adult periodontitis patients. Enterococcus faecalis was the only enterococcal species recovered, and all but one isolate belonged to the same biotype. In vitro antimicrobial sensitivity testing revealed subgingival enterococci resistant to therapeutic levels of penicillin G, tetracycline, clindamycin and metronidazole, but relatively sensitive to ciprofloxacin and amoxicillin/potassium clavulanate (Augmentin). Enterococci may populate periodontal pockets as superinfecting organisms and, in heavily infected patients, may contribute to periodontal breakdown.

This study examined the occurrence of non-oral gram-negative facultatively anaerobic rods in advanced adult periodontitis. Speciation and in vitro antimicrobial susceptibility testing was performed using the MicroScan micromethod system. A total of 42 taxa of Enterobacteriaceae, Pseudomonadaceae and Acinetobacter were isolated from 427 of 3,050 (14.0%) patients. In 159 (5.2%) patients, these organisms comprised more than 5% of the cultivable subgingival microflora. Enterobacter cloacae, Klebsiella pneumoniae, Pseudomonas aeruginosa, Klebsiella oxytoca and Enterobacter agglomerans accounted for more than 50% of all strains isolated. Virtually all study strains demonstrated high in vitro susceptibility to ciprofloxacin, but exhibited variable susceptibility patterns to 18 other antimicrobial agents tested. In 3 "refractory" periodontitis patients heavily infected with enteric rods, systemic ciprofloxacin therapy (500 mg BiD for 10 days) led to resolution of the subgingival infections and improved clinical periodontal status. The present findings indicate that 5% of severe periodontitis lesions may harbor high levels of non-oral, gram-negative, facultatively anaerobic rods. Systemic ciprofloxacin appears to be capable of eradicating these potential pathogens from deep periodontal pockets.

The occurrence of subgingival staphylococci was determined in 506 individuals with advanced adult periodontitis, 108 with early-onset periodontitis, 13 with localized juvenile periodontitis, 18 with gingivitis, and 13 with 20 failing osseointegrated titanium dental implants. Subgingival samples were collected with paper points and transported in VMGA III. The bacterial samples were plated on Staphylococcus 110 medium which was incubated in 10% CO2, and on enriched brucella blood agar, which was incubated anaerobically. Staphylococcal isolates from 94 adult periodontitis subjects were speciated using the API STAPH Trac micromethod kit system and the Bacto Staph latex agglutination test for coagulase activity. Staphylococcus epidermidis comprised 45.8% and Staphylococcus aureus 22.3% of total staphylococcal isolates. At 1 microgram/ml, in vitro resistance by staphylococci was found to tetracycline (14.4% of isolates), penicillin (4.9%), erythromycin (12.1%), and metronidazole (31.9%). Subgingival staphylococci were isolated from approximately 50% of gingivitis and periodontitis patients. No statistically significant differences were found between these patient groups in the prevalence or mean proportions of staphylococci recovered. "Periimplantitis" lesions exhibited significantly higher proportions of staphylococci (15.1%) than gingivitis (0.06%) or periodontitis (1.2%) lesions. Staphylococci may play a role in some failing osseointegrated dental implants.

Peptostreptococcus micros is a recognized pathogen in medical infections, and its association with progressive periodontitis was examined in this study. P. micros was isolated from paper-point subgingival samples on anaerobic enriched blood agar plates and identified on the basis of cellular and colonial morphology and selected biochemical tests. In a cross-sectional study involving 907 people with advanced adult periodontitis, 127 with early-onset periodontitis, and 12 with localized juvenile periodontitis, P. micros in these patient groups occurred with a prevalence of 58-63%. In culture-positive patients, P. micros averaged 12-15% of total viable counts. P. micros demonstrated similar occurrence and proportional recovery in all age groups. In a longitudinal study of 91 adult periodontitis patients on maintenance therapy, P. micros demonstrated a significantly higher prevalence in disease-active than in disease-inactive patients (47% vs 14%). Mechanical subgingival debridement and 0.12% chlorhexidine pocket irrigation was unable to eradicate subgingival P. micros from 18 of 22 adult periodontitis patients. In vitro antimicrobial susceptibility testing showed P. micros to be sensitive to therapeutic levels of penicillin, clindamycin and metronidazole. Our findings indicate that P. micros is a potential pathogen in adult periodontitis. The methods for its eradication from subgingival sites remain to be determined.

The subgingival microbiota in 14 persons with HIV‐periodontitis was examined. Subgingival plaque samples were collected with paper points, transported in VMGA III, and plated on anaerobic enriched brucella blood agar and various selective media. HIVperiodontitis sites revealed Actinobacillus actinomycetemcomitans, Wolinella recta, Peptostreptococcus micros, and Bacteroides intermedias, each averaging 7% to 16% of the cultivable subgingival flora in positive patients. High levels of spirochetes also were detected in diseased sites with phase‐contrast microscopy. Low levels of Candida albicans or enteric Gram‐negative rods were recovered in the subgingival flora in 7 HIVperiodontitis patients or Bacteroides fragilis, Fusobacterium necrophorum, Fusobacterium varium, and Eubacterium aerofaciens were recovered in 8 patients. These findings suggest that the major components of the subgingival microbial flora in HIV‐periodontitis are similar to those associated with adult periodontitis in systemically healthy persons. However, HIV‐periodontitis lesions also may contain organisms which are rarely found in common types of periodontitis. The etiological significance of specific periodontal organisms in HIV‐periodontitis awaits further longitudinal study. J Periodontol 1991;62:74– 81.