Investigation of six selected bacterial species in endo-periodontal lesions.

AIM: To investigate and determine possible associations of six tested bacteria belonging to 'orange' and 'green' complexes, in endo-periodontal lesions: Parvimonas micra, Fusobacterium nucleatum, Campylobacter rectus, Eubacterium nodatum, Eikenella corrodens and Capnocytophaga sputigena. METHODOLOGY: Forty-six patients presenting with different types of endo-periodontal lesions were investigated. Clinical examinations, periapical radiographs and microbiological sampling from the canal system (endo) and periodontal pockets (perio) were performed. Qualitative and semiquantitative evaluation of bacteria was performed by polymerase chain reaction (PCR) and DNA-DNA hybridization (micro-IDent plus; Hain Lifescience, Germany). RESULTS: Extremely high bacterial loads in endodontic samples were recorded for P. micra, F. nucleatum and C. sputigena, while periodontal samples were often colonized by the same species, plus C. rectus. Significant association was recorded between F. nucleatum-endo and P. micra-endo (P = 0.03, Fisher's exact test). There was marginal evidence of associations between: (i) C. sputigena-endo and C. sputigena-perio (P = 0.06, Fisher's exact test); (ii) P. micra-endo and P. micra-perio (P = 0.05, Fisher's exact test). Sensitivity to percussion was associated with an increased chance of cases with P. micra-endo (P = 0.03, Pearson chi-square test). CONCLUSION: The findings suggest that F. nucleatum, P. micra and C. sputigena may play a role in the pathogenesis of endo-periodontal lesions.

Susceptibility testing of Streptococcus mitis group isolates.

BACKGROUND & OBJECTIVES: Suppurative oral and maxillofacial infections are usually mixed infections due to aerobic and anaerobic bacteria, most frequently by oral streptococci and antimicrobial treatment is necessary for such infections. The aim of this study was to investigate the antimicrobial susceptibility of Streptococcus mitis group strains isolated from Romanian patients with different oral and maxillofacial infections. METHODS: Eighty-five isolates belonging to S. mitis group isolated from pus samples were identified at species level by the Rapid ID 32 STREP system. The E test was used to determine the susceptibilities of the isolates to penicillin, ampicillin, cefotaxime, erythromycin, clindamycin, chloramphenicol and tetracycline. RESULTS: Of the 151 samples studied, 85 isolates belonged to S. mitis group. The minimum inhibitory concentration (MIC) values (mg/l) ranged from 0.016-0.75 for penicillin, 0.016-2 for ampicillin, 0.016- 1 for cefotaxime, 0.016-4 for erythromycin, 0.016-0.047 for clindamycin, 0.5-4 for chloramphenicol and 0.047-256 for tetracycline. INTERPRETATION & CONCLUSION: The low susceptibility and the resistance to some commonly used antibiotics found in this study indicated a need for a careful surveillance of the susceptibility pattern of oral streptococci isolates of clinical significance. Clindamycin and chloramphenicol might be suitable alternative agents in treatment of oral and maxillofacial infections involving penicillin-resistant bacteria and in case of patients with hypersensitivity to beta-lactam antibiotics.

Streptococci species of anginosus group isolated from oral and maxillofacial infections.

The aim of the study was to isolate and identify at species level streptococci strains of anginosus group in pus samples collected from 110 patients with oral and maxillofacial (OMF) infections. Gram-stained smears and cultures on selective and nonselective media were done from each of the 111 pus samples (2 samples were collected from one of the patients, who presented 2 oral abscesses at the same time). The isolates were identified on the basis of cultural and biochemical characteristics. Speciation of the anginosus group isolates was performed using the Rapid ID 32 Strep system (Bio Mérieux, France). Fourty-four anginosus group strains were isolated from 42 patients. Fourty of these isolates were identified as Streptococcus anginosus (2 nonidentical isolates were found in 2 patients), 3 isolates as Streptococcus constellatus and only one as Streptococcus intermedius. The study confirmed that the anginosus group is often involved in OMF infections alone or in association with other aerobic and/or anaerobic bacteria. In the investigated cases, Streptococcus anginosus was by far the most frequently isolated species within the anginosus group.

Antimicrobial susceptibility of some streptococci strains of anginosus group isolated from oral and maxillofacial infections.

Streptococci strains of the anginosus group isolated from various oral and maxillofacial infections (OMF) were screened for their susceptibility to the following antimicrobial agents: benzylpenicillin, ampicillin, oxacillin, cephalothin, ceftazidime, cefotaxime, cefuroxime, erythromycin, clindamycin, tetracycline, chloramphenicol, vancomycin and trimethoprime-sulphamethoxazole. The isolates were susceptable to: clindamycin, chloramphenicol, vancomycin and all beta-lactam antibiotics, except ceftazidime to which 54.5% of the strains showed intermediate susceptibility. Intermediate susceptibility to tetracycline was found in 11.3% of the strains, whereas resistance to the same antibiotic was demonstrated in 61.4%. Resistance to erythromycin and trimethoprime-sulphamethoxazole was of 2.3% for both. In conclusion, penicillin is the drug of choice in infections caused by streptococci of the anginosus group.

Isolation and speciation of Prevotella strains from periodontal abscesses.

The aims of the study were to isolate and to identify at species level the Prevotella strains in pus samples collected by needle aspiration from 25 Romanian patients with periodontal abscesses. Gram-stained smears and cultures on selective and nonselective media were performed from each of the 25 pus samples. The isolates were identified on the basis of Gram staining, cultural characteristics and standard biochemical reactions. The Gram-negative anaerobic bacilli isolates were biochemically characterized and identified at species level using the Rapid ID 32 A system (Bio Mérieux, France). Fifteen Prevotella isolates belonging to one of the following species: P. melaninogenica, P. denticola, P. oralis, P. loescheii and P. bivia were recovered. All Prevotella isolates reacted similarly in 20 tests in the Rapid ID 32 A system. The P. melaninogenica strain showed approximately the same biochemical profile and only two sugar fermentation tests were not constantly positive. The study confirmed that Prevotella is often involved in periodontal abscesses (> 50% of the cases) in association with other anaerobic or/and aerobic bacteria. P. melaninogenica was the most frequently isolated Prevotella species from the investigated cases.

Phenotypic characterization of some anginosus group isolates from oral and maxillofacial infections.

The aim of this study was to briefly characterize serologically, biochemically and from the cultural point of view some anginosus group isolates found in pus samples collected from patients with oral and maxillofacial infections. Cultural characterization was done by studying the culture odor, the colony size and aspect, and hemolysis type on Columbia bood agar (BA). Lancefield grouping was made on cards using the rapid latex-agglutination test (Slidex Strepto-Kit, Bio Mérieux, France). The biochemical characterization was performed at the same time with the speciation by the Rapid ID 32 Strep system (Bio Mérieux, Marcy-l'Etoile, France). The anginosus group isolates were phenotypically heterogenic. Based on phenotypic description, nonidentical anginosus group isolates were found in the same patient sample.

Viability of four putative periodontal pathogens and enteric rods in the anaerobic transport medium VMGA III.

The aim of this study was to determine the survival in VMGA III of Porphyromonas gingivalis, Prevotella intermedia, Fusobacterium nucleatum, Actinobacillus actinomycetemcomitans and enteric rods in laboratory cultures as well as in subgingival plaque samples. Laboratory strains of the 4 putative periodontal pathogens and Escherichia coli were used in the laboratory part of this study. Also, 31 subgingival plaque samples were obtained from 22 periodontal patients and stored in VMGA III. Each sample, from both the laboratory and the clinical parts, was divided into 3 portions. One portion was cultured within a few hours of collection (baseline), while the second was processed after 24 h (day 2) and the third 48 h later (day 3). The results of the clinical part indicate that the detection frequencies of all 4 periodontal pathogens and their levels in positive samples decreased, to different degrees, by day 2 and decreased further by day 3. Enteric rods were not detected in base line samples. However, they were present in 16.1% and 22.6% of day 2 and day 3 samples, respectively. Similarly, the laboratory results demonstrate a significant decrease in the levels of the 4 periodontal pathogens tested by day 2 and day 3, whereas the opposite occurred for E. coli. P. gingivalis, P. intermedia, and F. nucleatum survived better in the presence of E. coli than alone, whereas A. actinomycetemcomitans survived less well when co-inoculated with E. coli. VMGA III appears to maintain microbial population ratios for periods up to 24 h. After 24 h, the multiplication of enteric organisms may alter the original proportions of the sample.

Significance of the positivity of some ELISA tests different as concerning the antigenic source in interpreting the western blot indeterminate sera in monitoring the epidemiology of high risk populations.

The paper analyses 50 pairs of sera pre-elevated within the "sentinel" epidemiological surveillance in a population exposed to a high risk at a 2 months interval. At the first determination all these sera showed an indeterminate Western Blot pattern; after 2 months, 93.7% revealed the occurrence of a certainly positive pattern. The paper is an analysis of the way in which different ELISA kits diagnosed at the first determination the Western Blot indeterminate sera. The purpose of the paper is to adopt a methodology of accurately diagnosing HIV infections in a population exposed to a high risk within an epidemiological surveillance of the "sentinel" type where the receiving of a second serum sample is quite difficult.