Mecillinam activity compared to ampicillin, trimethoprim/sulfamethoxazole, ciprofloxacin and nitrofurantoin against urinary tract isolates of gram-negative bacilli.
Recent Canadian, American and European studies have reported increased ampicillin and trimethoprim/sulfamethoxazole resistance among urinary tract isolates of Escherichia coli. This trend suggests that a reevaluation of first- and second-line therapies for the treatment of community-acquired urinary tract infections is necessary. Mecillinam, a beta-lactam with preferential activity against gram-negative penicillin binding protein 2 (unlike other beta-lactams which preferentially bind gram-negative penicillin binding proteins 1a, 1b or 3), may offer clinically significant activity against ampicillin-resistant and trimethoprim/sulfamethoxazole-resistant E. coli. To test this assertion, the activity of mecillinam was compared with ampicillin, trimethoprim/sulfamethoxazole, nitrofurantoin and ciprofloxacin against 258 consecutive gram-negative urinary tract isolates collected at a Canadian tertiary care hospital. Mecillinam demonstrated significantly better activity than ampicillin and trimethoprim/sulfamethoxazole and significantly less activity than ciprofloxacin and nitrofurantoin against the 258 isolates tested. Against E. coli isolates specifically, mecillinam was significantly more active than ampicillin and trimethoprim/sulfamethoxazole (p < 0. 001) and as active as ciprofloxacin and nitrofurantoin. Mecillinam was active against 91.9% of ampicillin-resistant E. coli and 95.9% of trimethoprim/sulfamethoxazole-resistant E. coli. We conclude that mecillinam should be reevaluated for potential use in the treatment of community-acquired urinary tract infections.
Zhanel
G G
GG
Department of Medical Microbiology, Faculties of Medicine, University of Manitoba, Winnipeg, Man., Canada. ggzhanel@pcs.mb.ca
Karlowsky
J A
JA
Schwartz
B
B
Jensen
S B
SB
Hoban
D J
DJ
D000560:Amdinocillin / Q000494:pharmacology; D000667:Ampicillin / Q000494:pharmacology*; D000890:Anti-Infective Agents / Q000494:pharmacology*; D000892:Anti-Infective Agents, Urinary / Q000494:pharmacology*; D002939:Ciprofloxacin / Q000494:pharmacology*; D006090:Gram-Negative Bacteria / Q000187:drug effects*; D016905:Gram-Negative Bacterial Infections / Q000652:urine; D006801:Humans; D008826:Microbial Sensitivity Tests; D009582:Nitrofurantoin / Q000494:pharmacology; D010406:Penicillins / Q000494:pharmacology*; D015662:Trimethoprim, Sulfamethoxazole Drug Combination / Q000494:pharmacology
D000890:Anti-Infective Agents; D000892:Anti-Infective Agents, Urinary; D010406:Penicillins; D002939:Ciprofloxacin; D000667:Ampicillin; D015662:Trimethoprim, Sulfamethoxazole Drug Combination; D009582:Nitrofurantoin; D000560:Amdinocillin