Antimicrobial susceptibility of subgingival bacterial flora in dogs with gingivitis

The aerobic and anaerobic flora from gingival pockets of 49 dogs with severe gingivitis and periodontitis were cultured. The susceptibility of each isolate to four antimicrobial agents currently approved for veterinary use in the USA (amoxicillin-clavulanic acid; clindamycin; cefadroxil; and enrofloxacin) was determined. Amoxicillin-clavulanic acid (Clavamox Pfizer Animal Health) had the highest in-vitro susceptibility against all isolates (96%), all aerobes (94%) and all anaerobes (100%) tested. For gram-negative aerobes, enrofloxacin (Baytril, Bayer Corp.) had the highest in-vitro susceptibility activity. For bacteria associated with treatment of gingivitis, which typically are mixed aerobic/anaerobic and gram-positive/gram-negative organisms, the antimicrobial of choice for clinical use based on these susceptibility tests is amoxicillin-clavulanic acid.