In vitro evaluation of cefepime and other broad-spectrum β-lactams for isolates in Malaysia and Singapore medical centers

• Published in: Diagnostic microbiology and infectious disease Vol. 35; no. 4; pp. 277 - 283
• Main Authors: Biedenbach, Douglas J., Lewis, M.Todd, Jones, Ronald N.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 01-12-1999; Elsevier
• Subjects: Antibiotics. Antiinfectious agents. Antiparasitic agents; Antiseptics; Bacteriology; Biological and medical sciences; Epidemiology; Fundamental and applied biological sciences. Psychology; Medical sciences; Microbiology; Pharmacology. Drug treatments; Tropical medicine; Asia; Malaysia; Singapore; Cephalosporin derivatives; Antibiotic; Sensitivity resistance; Cefepime; β-Lactams; Minimum inhibitory concentration; Activity spectrum; Antibacterial agent; Epidemiology; In vitro; Biological activity
• ISSN: 0732-8893; 1879-0070
• DOI: 10.1016/S0732-8893(99)00098-X

The degree of activity of several β-lactam antimicrobial agents was assessed in Malaysia (four medical centers) and Singapore (two medical centers) tested against 570 clinical isolates. The organisms were tested locally by the Etest (AB BIODISK, Solna, Sweden) method, validated by concurrent use of quality assurance strains (94.1% accurate performance overall). Ten groups of bacteria were tested against cefepime, cefpirome, ceftazidime, ceftriaxone, piperacillin/tazobactam, oxacillin, and imipenem. Among the tested
Escherichia coli and
Klebsiella spp., the occurrence of extended spectrum β-lactamase-producing phenotypes was 5.6–7.0% and 36.7–38.0%, respectively. These strains remained most susceptible (97.5–100.0%) to cefepime and imipenem. Ceftazidime-resistant
Enterobacter spp. (21.4% resistant),
Citrobacter spp. (15.0%), indole-positive
Proteus spp. (6.0%), and
Serratia spp. (9.7%) were
not resistant to cefepime, and only one strain was resistant to imipenem. Imipenem was generally most potent against nonfermentative Gram-negative bacilli such as
Acinetobacter spp. and
Pseudomonas aeruginosa. All tested β-lactams were active against the oxacillin-susceptible staphylococci, except ceftazidime (MIC
90, 12 μg/mL; 63.2–84.8% susceptibility rates). Overall spectrums of activity (rank by % resistance) favored imipenem (3.5%) > cefepime (7.7%) > cefpirome (8.9%) > piperacillin/tazobactam (13.2%) > ceftriaxone (14.7%) > ceftazidime (16.9%). No significant differences in resistance patterns were noted between monitored nations, and these results indicate emerging, elevated rates of resistance versus the studied broad-spectrum β-lactams in Malaysia and Singapore. Results provide benchmark data for future studies using quantitative methods to determine antimicrobial resistance in these geographic areas.