The antimicrobial susceptibility of 176 unusual non-fermentative gram-negative bacilli (NF-GNB) collected from Latin America region through the SENTRY Program between 1997 and 2002 was evaluated by broth microdilution according to the National Committee for Clinical Laboratory Standards (NCCLS) recommendations. Nearly 74% of the NF-BGN belonged to the following genera/species:
Burkholderia spp. (83),
Achromobacter spp. (25),
Ralstonia pickettii
(16),
Alcaligenes spp. (12), and
Cryseobacterium spp. (12). Generally, trimethoprim/sulfamethoxazole (MIC
50, ≤ 0.5 μg/ml) was the most potent drug followed by levofloxacin (MIC
50, 0.5 μg/ml), and gatifloxacin (MIC
50, 1 μg/ml). The highest susceptibility rates were observed for levofloxacin (78.3%), gatifloxacin (75.6%), and meropenem (72.6%). Ceftazidime (MIC
50, 4 μg/ml; 83.1% susceptible) was the most active β-lactam against
B. cepacia. Against
Achromobacter spp. isolates, meropenem (MIC
50, 0.25 μg/ml; 88% susceptible) was more active than imipenem (MIC50, 2 μg/ml). Cefepime (MIC
50, 2 μg/ml; 81.3% susceptible), and imipenem (MIC
50, 2 μg/ml; 81.3% susceptible) were more active than ceftazidime (MIC
50, >16 μg/ml; 18.8% susceptible) and meropenem (MIC
50, 8 μg/ml; 50% susceptible) against
Ralstonia pickettii. Since selection of the most appropriate antimicrobial agents for testing and reporting has not been established by the NCCLS for many of NF-GNB species, results from large multicenter studies may help to guide the best empiric therapy.
