Detection and prevalence of the tetracycline resistance determinant Tet Q in the microbiota associated with adult periodontitis

Abstract

Subgingival plaque samples were collected from 68 patients with a history of moderate to severe adult periodontitis and enumerated on Trypticase-soy blood agar plates, with and without tetracycline at 4 micrograms/ml. Each different colony morphotype was enumerated, and a representative colony was subcultured for identification and examined for the tetracycline resistance gene tet(Q) by polymerase chain reaction (PCR) amplification and DNA hybridization, using a fragment of tetA(Q)2 from Bacteroides fragilis 1126. PCR primers (5'-GGCTTCTACGACATCTATTA-3' and 5'-CATCAACATTTATCTCTCTG-3') were chosen to amplify a 755 bp region of tet(Q). The subgingival plaque samples were also tested by PCR. Approximately 12% of the total cultivable flora was resistant to tetracycline, and the percentage of the tetracycline-resistant cultivable flora with the tet(Q) gene varied greatly from one patient to another with a range from 0.0 to 67%. Half of the 68 subgingival plaque samples were positive or weakly positive for tet(Q) by PCR. Approximately 15% of the 210 isolates subcultured with resistance to tetracycline, (> or = 4 micrograms/ml) contained tet(Q), and 60% contained tet(M). All of the tet(Q)-resistant isolates were gram-negative anaerobic bacilli and included all of the Prevotella and Bacteroides isolates.

Inhibitory activity of Aloe vera gel on some clinically isolated cariogenic and periodontopathic bacteria

“…These periodontopathogens are frequently isolated from periodontal pockets of patients with periodontitis, but up to now it has been unclear which species play the main role in pathogenesis. In this study, B. fragilis was used as an example of an opportunistic periodontopathogen, as many reports have documented the isolation of B. fragilis from dental plaque or periodontal pockets of patients with periodontitis (23)(24)(25).…”

Molecular Detection of Antimicrobial Resistance

“…Approximately 15% of the 210 isolates subcultured that had resistance to tetracycline and belonged to different species contained tetQ, and 60% contained tetM. All of the tetQ-containing isolates were gram-negative anaerobic bacilli and included all of the Prevotella and Bacteroides isolates (160,161).…”

“…The nonpathogens in each of the ecosystems may play an important role as reservoirs for the antibiotic resistance genes. Several authors used PCR to detect special tet genes in bacteria from clinical samples (29,129,160,161,226,238,266,271,359,381,394). PCR was evaluated with various genera and different clinical samples, e.g., vaginal swab specimen from women with vaginitis (270), semen specimens from men with prostatitis (271), and the oral microflora of patients with adult periodontitis (160,169,226).…”

“…All isolates gave positive PCR products which hybridized with labeled TetK or TetL probes. Lacroix and Walker reported the development of PCR assays for the detection of tetM and tetQ genes in the microflora associated with adult periodontitis (160,161). Subgingival plaque samples were collected from 68 patients with adult periodontitis, enumerated on Trypticase soy blood agar plates with or without tetracycline, and incubated.…”

Characterization of a Bacteroides Mobilizable Transposon, NBU2, Which Carries a Functional Lincomycin Resistance Gene

“…Gene transfer from Bacteroides donors to members of other genera has already been observed in the laboratory (26,41,45). Evidence for transfer of genes in the environment has been indicated by the appearance of the Bacteroides tetracycline resistance gene, tetQ, in other genera, mostly human-associated gram-negative anaerobes (12,13,17,18,25). It remains to be seen whether transfer is also occurring between Bacteroides species and the gram-positive colonic anaerobes that are also a major component of the colon microflora.…”