Sequencing of a tet(Q) gene isolated from Bacteroides fragilis 1126

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.

Section: Discussionmentioning

confidence: 92%

“…A 1535-bp Pvull-EcoBJ fragment containing an internal portion of the te-tA{Q)2 gene from B. fragilis 1126 (20) was isolated from the plasmid pBSKl.2-5 (Bluescript II SK+ Q. 2.8 kb Smal-Clal fragment, containing te-tA(Q)2, from the chromosomal DNA of B. fragilis 1126), which was kindly given to us by DG.…”

Section: Fef (Q) Probe For Dna-dna Hybridizationmentioning

confidence: 99%

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

Lacroix

Walker

1996

“…The cotransfer of tetracycline and penicillin resistance genes in black‐pigmented strains is probably related to a conjugation system encoded by chromosomal transposons ( 16, 24, 26). The strains producing a β‐lactamase but susceptible to tetracycline could have deletion in the tetQ gene or a low‐level minimal inhibitory concentration increase not easily detectable ( 27). The past use of tetracycline in the treatment of oral infections may have contributed to develop the resistance to β‐lactam antibiotics as well, and conversely the present use of β‐lactam antibiotics may contribute to partially stabilize tetracycline resistance in oral gram‐negative anaerobic rods ( 26, 33).…”

Section: Discussionmentioning

confidence: 99%

“…Aminopenicillins are still commonly used, and these β‐lactamases cannot be ignored as a threat of inactivating β‐lactam antibiotics in the subgingival environment, thus protecting endogenous flora and other pathogens, particularly oral streptococci, during acute infections. The question is addressed as well as the potential role of this reservoir of β‐lactamase genes, and additional clinical, epidemiological and genetic surveys are necessary ( 8, 18, 21, 27, 45).…”

Section: Discussionmentioning

confidence: 99%

Prevalence of β‐lactamase‐producing strains among 149 anaerobic gram‐negative rods isolated from periodontal pockets

Fosse

Madinier

Hitzig

et al. 1999

In a prospective study, 47 adults presenting a rapidly progressive periodontitis were selected in order to evaluate the prevalence of beta-lactamase-producing strains among oral anaerobic gram-negative rods. Predominant anaerobes were identified from two of the deepest periodontal pockets. beta-Lactamase-positive strains fulfilled to at least two of three criteria: positive nitrocefin test, penicillin Etest minimal inhibitory concentration > 1 microgram/ml, and disk diffusion synergy between amoxycillin and clavulanic acid > 10 mm. At least one beta-lactamase-producing strain was found in 53.2% of patients and 39.4% of the periodontal pockets investigated. Prominent beta-lactamase-positive species were Prevotella buccae and Prevotella intermedia (respectively 16 of 38: 42% and 18 of 52: 35% positive strains), followed by Prevotella bivia, Prevotella disiens, Prevotella denticola and Fusobacterium nucleatum (respectively 1 of 6: 17%, 1 of 10: 10%, 1 of 10: 10%, and 1 of 13: 8% positive strains). No beta-lactamase producer could be evidenced in Porphyromonas gingivalis (10 strains tested). All the beta-lactamase-positive strains with the nitrocefin test had penicillin minimal inhibitory concentrations > 1 microgram/ml with the Etest, and a strong synergy between amoxicillin and clavulanic acid was always observed.

“…The tetracycline-resistance genes frotn Bacteroides fragilis and Bacteroides thetaiotaomierott have been sequenced (11,17), and the genes share 97.3% and 97.0% of amino acid and DNA sequences respectively (11). The /i;'/(Q) gene from pNFDI3-2 also has a 51.5% to 52.6% DNA sequence homology with the tet(M) and tet(O) genes (17).…”

mentioning

confidence: 99%

The tet(Q) gene in bacteria isolated from patients with refractory periodontal disease

Olsvik¹,

Olsen²,

Tenover³

1994

Twenty-two tetracycline-resistant (tetr) anaerobic and facultative anaerobic bacteria isolated from periodontal pockets of 12 patients with refractory periodontitis were examined for the presence of the Tet Q determinant by DNA-DNA hybridization. Dot blots of bacterial DNA were tested with an intragenic digoxigenin-labelled tet(Q) probe consisting of a 1.45 kb EcoRI/PvuII fragment from plasmid pNFD13-2. Southern blots of chromosomal DNA digested with the restriction enzyme EcoRI were also examined. The tet(Q) probe hybridized with DNA from 8 of the 22 tetr strains, including 2 Prevotella intermedia strains and one strain each of Prevotella nigrescens, Prevotella loescheii, Prevotella veroralis and Prevotella melaninogenica. The tetr strains of Mitsuokella dentalis and Capnocytophaga ochracea also hybridized with the probe. The lack of discernible plasmid DNA in all the probe-positive isolates suggests that these tetracycline-resistance genes were chromosomally encoded. The probe hybridized with a different size fragment in all the isolates. This study extends the number of species that carry the tet(Q) gene to include several outside the genera Prevotella and Bacteroides.