In vitro susceptibility of recent antibiotic-resistant urinary pathogens to ertapenem and 12 other antibiotics

• Published in: Journal of antimicrobial chemotherapy Vol. 53; no. 6; pp. 1090 - 1094
• Main Authors: Alhambra, A., Cuadros, J. A., Cacho, J., Gómez-Garcés, J. L., Alós, J. I.
• Format: Journal Article
• Language: English
• Published: Oxford Oxford University Press 01.06.2004; Oxford Publishing Limited (England)
• Subjects: Anti-Bacterial Agents - pharmacology; antibiotic susceptibility; Antibiotics. Antiinfectious agents. Antiparasitic agents; beta-Lactamases - metabolism; beta-Lactams - pharmacology; Biological and medical sciences; carbapenems; Drug Resistance, Bacterial; Enterobacter; Enterobacteriaceae; Enterobacteriaceae - drug effects; Enterobacteriaceae - genetics; Enterobacteriaceae Infections - microbiology; Escherichia coli; Genes, Bacterial - genetics; Humans; Klebsiella; Lactams; Medical sciences; Microbial Sensitivity Tests; Pharmacology. Drug treatments; Proteus mirabilis; Proteus vulgaris; urinary tract infections; Urinary Tract Infections - microbiology; Carbapenem derivatives; Antibiotic; Drug susceptibility test; Antibacterial agent; Ertapenem; β-Lactams
• ISSN: 0305-7453; 1460-2091; 1460-2091
• DOI: 10.1093/jac/dkh218

Background: The treatment of complicated urinary tract infections may require the use of a parenteral antibiotic with potent activity against the most common urinary pathogens. Ertapenem is a broad-spectrum 1β-methyl carbapenem with a long plasma half-life that allows administration of a single daily dose. Methods: The purpose of this work was to test the in vitro susceptibility to ertapenem, ampicillin, cefazolin, cefuroxime, cefotaxime, co-amoxiclav, piperacillin/tazobactam, imipenem, gentamicin, amikacin, fosfomycin, ciprofloxacin and co-trimoxazole of 482 strains of urinary pathogens of the family Enterobacteriaceae isolated from patients in the community of Madrid (40% from males). The distribution was as follows: Escherichia coli (n = 315), Proteus mirabilis (n = 42), Klebsiella spp. (n = 14) and AmpC-producing Enterobacteriaceae (n = 111). The strains studied were selected based on their resistance to quinolones and aminoglycosides, and their production of extended-spectrum β-lactamases (ESBLs) or AmpC-type β-lactamases. Results: All the strains were susceptible to ertapenem, imipenem and amikacin. The MIC90 of ertapenem ranged from a minimum of 0.03 mg/L for Proteus vulgaris and a maximum of 1 mg/L for Enterobacter spp. Ertapenem was the most active of all drugs tested in all cases. On comparing antibiotic resistance among ESBL-producing strains of E. coli (n = 35) and E. coli strains not producing ESBLs (n = 280), statistically significant differences were obtained for ciprofloxacin (P = 0.002) and gentamicin (P = 0.011). Regarding ertapenem, only a slight increase in MIC50 was seen, the value being 0.015 mg/L for strains not producing ESBLs versus 0.03 mg/L for ESBL-producing strains. Conclusions: In view of its significant antibiotic potency against antibiotic-resistant Enterobacteriaceae, ertapenem may constitute a good therapeutic alternative in urinary infections caused by these pathogens.