MICS OF 28 ANTIBIOTIC COMPOUNDS FOR 14 BARTONELLA (FORMERLY ROCHALIMAEA) ISOLATES

We assessed in vitro the antibiotic susceptibilities of 14 Bartonella isolates of the species B. quintana, B. vinsonii, B. henselae, and B. elizabethae. Columbia agar base supplemented with 5% horse blood was used as the antibiotic assay medium. Bacterial growth could be evaluated within 5 days after incubation of the plates at 37 degrees C in a 5% carbon dioxide atmosphere. The MICs at which 90% of isolates are inhibited (MIC(90)s) mere 0.06 mu g/ml for penicillin G and amoxicillin and 0.25 mu g/ml for ticarcillin and cefotaxime. The MIC(90)s of oxacillin and cephalothin were 4 and 16 mu g/ml, respectively. The MIC(90)s ranged from 1 to 4 mu g/ml for aminoglycosides. Erythromycin, doxycycline, and rifampin displayed MIC(90)s of 0.12, 0.12, and 0.25 mu g/ml, respectively. MIC(90)s were 1 and 5 mu g/ml for trinethoprim-and sulfamethoxazole, respectively, 64 mu g/ml for fosfomycin, and 16 mu g/ml for colistin and vancomycin. The study confirms the high levels of in vitro susceptibility of Bartonella agents to antibiotics.