amoxicillin-potassium-clavulanate-combination and nitrocefin

Susceptibility to beta-lactamic agents has changed among anaerobic isolates from acute endodontic infections. The aim of the present study was to determine the prevalence of the cfxA/cfxA2 gene in Prevotella spp., Porphyromonas spp., and Parviomonas micra strains and show its phenotypic expression.. Root canal samples from teeth with acute endodontic infections were collected and Porphyromonas, Prevotella, and Parvimonas micra strains were isolated and microbiologically identified with conventional culture techniques. The susceptibility of the isolates was determined by the minimum inhibitory concentration of benzylpenicillin, amoxicillin, and amoxicillin + clavulanate using the E-test method (AB BIODISK, Solna, Sweden). The presence of the cfxA/cfxA2 gene was determined through primer-specific polymerase chain reaction. The nitrocefin test was used to determine the expression of the lactamase enzyme.. Prevotella disiens, Prevotella oralis, Porphyromonas gingivalis, and P. micra strains were susceptible to benzylpenicillin, amoxicillin, and amoxicillin + clavulanate. The cfxA/cfxA2 gene was detected in 2 of 29 isolates (6.9%). Simultaneous detection of the cfxA/cfxA2 gene and lactamase production was observed for 1 Prevotella buccalis strain. The gene was in 1 P. micra strain but was not expressed. Three strains were positive for lactamase production, but the cfxA/cfxA2 gene was not detected through polymerase chain reaction.. There is a low prevalence of the cfxA/cfxA2 gene and its expression in Porphyromonas spp., Prevotella spp., and P. micra strains isolated from acute endodontic infections. Genetic and phenotypic screening must be performed simultaneously to best describe additional mechanisms involved in lactamic resistance for strict anaerobes.

Topics: Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteroidaceae Infections; beta-Lactam Resistance; beta-Lactamase Inhibitors; beta-Lactamases; Cephalosporins; Dental Pulp Diseases; Gram-Positive Bacterial Infections; Humans; Indicators and Reagents; Microbial Sensitivity Tests; Penicillin G; Peptostreptococcus; Phenotype; Porphyromonas; Porphyromonas endodontalis; Porphyromonas gingivalis; Prevotella; Prevotella intermedia; Prevotella nigrescens

Samples were taken under strictly anaerobic conditions from the root canals of 22 patients having a tooth in which necrotic pulp was associated with an inflammatory peri-apical lesion an optical periodontitis. In the majority of cases (85%), these lesions were chronic and the pulp chamber was closed. One hundred and two strains were isolated, 71.7% of the bacteria being obligate anaerobes and 49.8% being Gram-negative bacilli. Their ability to produce beta-lactamases was tested and 8.8% gave a positive reaction in a cefinase test. These cefinase positive strains were nevertheless susceptible to 3rd-generation cephalosporins (cefoxitin) and to amoxicillin-clavulanate, with the exception of M. Morganii.

Topics: Actinomyces; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteriological Techniques; Bacteroides; beta-Lactam Resistance; beta-Lactamases; Cefoxitin; Cephalosporins; Dental Pulp Cavity; Dental Pulp Necrosis; Gram-Negative Bacteria; Gram-Positive Bacteria; Humans; Indicators and Reagents; Peptostreptococcus; Periapical Periodontitis; Prevotella; Streptococcus

In 23 untreated adult periodontitis patients, the occurrence of beta-lactamase producing periodontal bacteria was determined. In addition to non-selective isolation media, selective isolation and growth of beta-lactamase positive subgingival bacterial species was carried out on blood agar plates supplemented with amoxicillin and plates with amoxicillin+clavulanic acid. Porphyromonas gingivalis, Prevotella intermedia, Actinobacillus actinomycetemcomitans, Peptostreptococcus micros, Fusobacterium nucleatum, Bacteroides forsythus and Campylobacter rectus isolates from the non-selective medium were tested for beta-lactamase activity by a nitrocefin disk method (DrySlide) and by a laboratory chromogenic nitrocefin-based test. Isolates from the amoxicillin plates that were absent on the amoxicillin/clavulanic acid plates were identified and tested for beta-lactamase production. Based on the non-selective plates, six of 23 P. intermedia isolates, 2 of 19 B. forsythus isolates and 3 of 23 F. nucleatum isolates were beta-lactamase positive. The beta-lactamase positive species Prevotella loescheii, Prevotella buccae, Prevotella buccalis and Actinomyces spp were recovered from the selective amoxicillin plates. beta-Lactamase positive subgingival species were recovered from 17 of 23 patients (74%) but usually comprised low proportions of the subgingival microbiota (range < 0.01-15%). Comparison of the DrySlide test and the nitrocefin-based laboratory test revealed full agreement of test results. beta-Lactamase activity in whole subgingival plaque was detected in 12 patient samples (52%). It was concluded that beta-lactamase activity in subgingival bacteria in adult periodontitis is a common feature. However, since the majority of the samples showed only low-level enzymatic activity, the clinical relevance of this observation with regard to therapy with unprotected enzyme-susceptible beta-lactams is uncertain, though failure on the other hand, is difficult to rule out when a mechanism of resistance is present. The majority of beta-lactamase positive strains was found among species of the Prevotella genus.

Topics: Actinomyces; Adult; Aggregatibacter actinomycetemcomitans; Amoxicillin; Amoxicillin-Potassium Clavulanate Combination; Anti-Bacterial Agents; Bacteria; Bacteroides; beta-Lactamases; Campylobacter; Cephalosporins; Chromogenic Compounds; Clavulanic Acids; Culture Media; Dental Plaque; Fusobacterium nucleatum; Gingiva; Humans; Indicators and Reagents; Penicillins; Peptostreptococcus; Periodontitis; Porphyromonas gingivalis; Prevotella; Prevotella intermedia