Multicenter evaluation of the antimicrobial activity for six broad-spectrum beta-lactams in Venezuela using the Etest method. The Venezuelan Antimicrobial Resistance Study Group.
In early 1997, a 15-laboratory surveillance project was initiated in Venezuela to monitor the potency and spectrum of 6 broad-spectrum antimicrobial agents (cefepime, cefotaxime, ceftazidime, piperacillin, piperacillin/tazobactam, and imipenem) tested against approximately 100 organisms per participant center (1297 strains). Ten groups of organisms were tested by the Etest method (AB BIODISK, Solna, Sweden) with results validated by concurrent quality control strain analysis. Results from all centers were tabulated and 96.3% of quality assurance tests were within ranges recommended by the National Committee for Clinical Laboratory Standards. Among the six beta-lactam class drugs tested, imipenem and cefepime were the most active against all isolates tested. Overall, the rank order of susceptibility of the six agents was imipenem (97.2%, susceptible; MIC90 2 micrograms/ml) > cefepime (92.8%; MIC90 6 micrograms/mL) > piperacillin/tazobactam (77.2-83.0%; MIC90 > 256 micrograms/mL) > cefotaxime (72.2%; MIC90 > 256 micrograms/mL) > piperacillin (56.8-65.8%; MIC90 > 256 micrograms/mL) > ceftazidime (64.66%; MIC90 128 micrograms/mL). Both cefepime and imipenem were active against ceftazidime-resistant strains of Enterobactericaeae as well as against Pseudomonas aeruginosa and oxacillin-susceptible staphylococci. Resistance phenotypes consistent with extended spectrum beta-lactamases (ESBLs) and stably derepressed Bush group 1 cephalosporinases were documented in strains of Klebsiella spp. and Enterobacters, respectively. These data should be used to guide empiric therapy with beta-lactams in Venezuela, and additionally will provide a reference statistical baseline to which future studies in this nation can be compared.
Pfaller
M A
MA
Department of Pathology, University of Iowa College of Medicine, Iowa City 52242, USA.
Jones
R N
RN
Doern
G V
GV
D000150:Acinetobacter / Q000187:drug effects; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D004352:Drug Resistance, Microbial; D018432:Drug Resistance, Multiple; D004755:Enterobacteriaceae / Q000187:drug effects* / Q000201:enzymology; D016946:Gram-Negative Aerobic Rods and Cocci / Q000187:drug effects*; D006801:Humans; D016106:Methicillin Resistance; D008826:Microbial Sensitivity Tests / Q000379:methods*; D011550:Pseudomonas aeruginosa / Q000187:drug effects; D011786:Quality Control; D015203:Reproducibility of Results; D013211:Staphylococcus aureus / Q000187:drug effects*; D014687:Venezuela; D001618:beta-Lactamases / Q000096:biosynthesis; D047090:beta-Lactams
D000900:Anti-Bacterial Agents; D047090:beta-Lactams; D001618:beta-Lactamases