DE AZAVEDO JC, KONG G, DUNCAN CL, PONG-PORTER S, MANDELL LA, LOW DE, BAST DJ; Interscience Conference on Antimicrobial Agents and Chemotherapy (43rd: 2003: Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2003 Sep 14-17; 43: abstract no. E-150.

Mount Sinai Hospital and University of Toronto, Toronto, ON, Canada.

BACKGROUND: E.coli is a significant cause of urinary tract infections. IDSA guidelines recommend CIP or levofloxacin (LEV) for treatment of acute uncomplicated pyelonephritis. Several studies have examined the in vitro activity of GRN against Gram-positive and anaerobic organisms, however, few have looked at the activity against E.coli. METHODS: We tested 745 isolates: 212 blood culture (BC), 196 urinary tract (UT) and 337 isolates (MDR) chosen on the basis of resistance to 2 of either cephalosporins, CIP or aminoglycosides. BC and UT isolates were obtained from 65 centers across Canada from 1999 to 2001. MDR isolates were collected from 1999 from 20 hospitals/nursing homes in south-central Ontario. GRN and CIP activity were tested following NCCLS guidelines. The quinolone resistance determining regions of the gyrA and parC genes of representative strains were amplified by PCR and sequenced. RESULTS: Of 408 BC and UT isolates, only 12 and 9 had MICs > 1mg/L to GRN and CIP respectively. Among MDR isolates, the GRN and CIP MICs were > 1mg/L for 299 (89%) and 298 (88%) isolates respectively. The MIC[90] for both GRN and CIP was 128mg/L. Among strains with a CIP MIC >/= 1mg/L, 73 had a CIP MIC more than 2-fold higher than the GRN MIC, 83 showed an equivalent MIC and 7 had a GRN MIC more than 2-fold higher than the CIP MIC. Among 58 strains with MICs of 1 to >/= 512 mg/L which were sequenced, all had substitutions in GyrA and all but one had substitutions in ParC. Among these, 12 (21%) had an up-regulated efflux mechanism. CONCLUSIONS: The activity of GRN is comparable to that of CIP against clinical isolates of E.coli and demonstrates potential for use not only against Gram-positive and anaerobic infections but also against Gram-negative infections.

Publication Types:

• Meeting Abstracts

Keywords:

• Base Sequence
• Canada
• Ciprofloxacin
• Escherichia coli
• Escherichia coli Infections
• In Vitro
• Microbial Sensitivity Tests
• Ofloxacin
• Ontario
• Urinary Tract Infections
• genetics
• methods

Other ID:

• GWAIDS0026433

UI: 102266057

From Meeting Abstracts