Distribution of erm(F) and tet(Q) genes in 4 oral bacterial species and genotypic variation between resistant and susceptible isolates.
BACKGROUND
Bacteroides forsythus, Porphyromonas gingivalis and Prevotella intermedia are Gram-negative anaerobic bacteria that are currently considered potential periopathogens. Prevotella nigrescens has recently been separated from P. intermedia and its rôle in periodontitis is unknown. The erm(F) gene codes for an rRNA methylase, conferring resistance to macrolides, lincosamides and streptogramin B (MLSB), and the tet(Q) gene for a ribosomal protection protein, conferring resistance to tetracycline. The presence of these resistance genes could impair the use of antibiotics for therapy.


OBJECTIVE
The aim of this study was to determine the carriage of erm(F) and tet(Q), and genetic variability of 12 Porphyromonas gingivalis, 10 Prevotella intermedia, 25 Prevotella nigrescens and 17 Bacteroides forsythus isolates from 9 different patient samples.


METHODS
We used polymerase chain reaction (PCR) for detecting antibiotic resistance genes, and pulsed-field gel electrophoresis (PFGE) for detecting genetic variability among the isolates.


RESULTS
Thirty-one (48%) isolates were resistant to both erythromycin and tetracycline and carried the erm(F) and tet(Q) genes, eight (13%) were tetracycline resistant and carried the tet(Q) gene, 9 (14%) were erythromycin resistant and carried the erm(F) gene, and 12 (19%) isolates did not carry antibiotic resistance genes. PFGE was used to compare isolates from the same patient and isolates from different patient samples digested with XbaI. No association was found between antibiotic resistance gene carriage and PFGE patterns in any species examined. All isolates of the same species from the same patient had highly related or identical PFGE patterns. Isolates of same species from different patients had unique PFGE pattern for each species tested.


CONCLUSIONS
All isolates of the same species from any one patient were genetically related to each other but distinct from isolates from other patients, and 66% of the patients carried antibiotic resistant isolates, which could impair antibiotic therapy.
Chung
Whasun O
WO
Department of Pathobiology, University of Washington, Seattle, WA 98195-7238, USA.
Gabany
Joseph
J
Persson
G Rutger
GR
Roberts
Marilyn C
MC
D018829:Adhesins, Bacterial / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D001439:Bacteroides / Q000235:genetics; D002874:Chromosome Mapping; D024881:Drug Resistance, Bacterial / Q000235:genetics*; D004352:Drug Resistance, Microbial; D016521:Electrophoresis, Gel, Pulsed-Field; D004917:Erythromycin / Q000494:pharmacology; D014644:Genetic Variation / Q000235:genetics; D005838:Genotype; D005891:Gingivitis / Q000382:microbiology; D006801:Humans; D008780:Methyltransferases / Q000235:genetics; D010518:Periodontitis / Q000382:microbiology*; D010641:Phenotype; D016133:Polymerase Chain Reaction; D016966:Porphyromonas gingivalis / Q000235:genetics; D018720:Prevotella / Q000235:genetics; D018713:Prevotella intermedia / Q000235:genetics; D013753:Tetracycline Resistance / Q000235:genetics*; D014157:Transcription Factors / Q000235:genetics
D018829:Adhesins, Bacterial; D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D014157:Transcription Factors; D004917:Erythromycin; D008780:Methyltransferases; C437393:ErmF protein, Bacteroides; C035181:rRNA (adenosine-O-2'-)methyltransferase