Susceptibility of oral obligate anaerobes to telithromycin, moxifloxacin and a number of commonly used antibacterials.
BACKGROUND
Obligate anaerobes are closely involved in the pathogenesis of oral and focal infections. The objective of this study was to evaluate the susceptibility profiles of obligate anaerobes of oral origin to telithromycin (TLM), moxifloxacin (MXF), and other antibiotics that are commonly used in dentistry.


METHODS
The study sample comprised 172 obligate anaerobes isolated from the saliva of 43 adult volunteers. The minimum inhibitory concentrations (MICs) were determined by the agar dilution technique in Brucella agar medium supplemented with vitamin K, haemin and 5% (volume/volume) laked sheep blood, and incubated under anaerobic conditions. The Clinical and Laboratory Standards Institute methodology was followed and its criteria were used for the qualitative interpretation of the results. The antibiotics evaluated were: amoxicillin (AMX), amoxicillin-clavulanic acid (AMX-CLA), clindamycin (CM), metronidazole (MTZ), azithromycin (AZM), TLM and MXF.


RESULTS
Resistance to AMX (MIC(90) > or = 16 mg/l) was observed in 45.3% of the obligate anaerobes and resistance to CM (MIC(90) > or = 16 mg/l) was found in 18.6%. All the isolates were sensitive to MTZ (MIC(90) = 1 mg/l) and 98.8% were sensitive to AMX-CLA (MIC(90) = 2 mg/l). The MIC(90) values for AZM, TLM and MXF were > or =16, > or =8 and > or =2 mg/l, respectively.


CONCLUSIONS
Pathogenic, opportunistic and non-pathogenic obligate anaerobes showed high percentages of resistance to AMX and CM, and high MIC values for AZM in the absence of recently administered antibiotics. MXF showed a higher activity than TLM, similar to that detected for AMX-CLA and MTZ. In consequence, MXF could represent a possible alternative antimicrobial against obligate anaerobes of oral origin, particularly in those patients with allergy, intolerance or lack of response to AMX-CLA or MTZ.
Tomás
I
I
Faculty of Medicine and Dentistry, Santiago de Compostela University, Santiago de Compostela, Spain.
Tomás
M
M
Alvarez
M
M
Velasco
D
D
Potel
C
C
Limeres
J
J
Diz
P
P
D000328:Adult; D000658:Amoxicillin / Q000494:pharmacology; D019980:Amoxicillin-Potassium Clavulanate Combination / Q000494:pharmacology; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology; D001372:Aza Compounds / Q000494:pharmacology*; D017963:Azithromycin / Q000494:pharmacology; D001769:Blood; D002981:Clindamycin / Q000494:pharmacology; D003470:Culture Media; D024881:Drug Resistance, Bacterial; D024841:Fluoroquinolones; D006089:Gram-Negative Anaerobic Bacteria / Q000187:drug effects*; D006427:Hemin; D006801:Humans; D048628:Ketolides / Q000494:pharmacology*; D008795:Metronidazole / Q000494:pharmacology; D008826:Microbial Sensitivity Tests; D000077266:Moxifloxacin; D010403:Penicillin Resistance; D010518:Periodontitis / Q000382:microbiology*; D011804:Quinolines / Q000494:pharmacology*; D012463:Saliva / Q000382:microbiology; D014812:Vitamin K