CANTON R, LOZA E, CONEJO M, BAQUERO F, MARTINEZ-MARTINEZ L; MENSURA COLLABORATIVE GROUP; Interscience Conference on Antimicrobial Agents and Chemotherapy (41st : 2001 : Chicago, Ill.).

Abstr Intersci Conf Antimicrob Agents Chemother Intersci Conf Antimicrob Agents Chemother. 2001 Dec 16-19; 41: abstract no. D-175.

Hospital Ramon y Cajal, Madrid, Spain

Quality control procedures using strains with defined resistance mechanisms may be very efficient to identify problems of susceptibility testing at national level. Eighteen Enterobacteriaceae and P. aeruginosa strains with well-defined resistance mechanisms were sent to 52 Spanish microbiology laboratories. Interpretative categories for 8 extended-spectrum beta-lactams were collected. Laboratories used their routine susceptibility testing procedures (88% automatic systems, 10% disk diffusion, and 2% agar dilution) and interpretations were made following NCCLS criteria, modified in 15% according to the Spanish Antibiogram Committee (MENSURA). Two central laboratories, using NCCLS microdilution and interpretative criteria, established reference values. High consistency, <5% of major + very major (MVM) discrepancies, was found for E. coli ATCC 25922 and the strains with OXA-1, K. pneumoniae with SHV-1 or SHV-5 + OprK35-, E. cloacae hyperproducing AmpC + CTX-M-10, and P. aeruginosa ATCC 27853 and the hyperproducing AmpC or MexAB-OprM strains. 5% < MVM <10% was found in AmpC hyperproducing E. coli, AmpC inducible E. cloacae and P. aeruginosa OprD-. 10%>MVM>20% was found in K. pneumoniae with SHV-5 and AmpC hyperproducing E. cloacae. 20%>MVM>30% in E. coli with TEM-27. The highest discrepancy was detected (30%>MVM>40%) in E. coli with CTX-M-10, K1-producing K. oxytoca, E. cloacae with CTX-M-10, and OprD- + AmpC hyperproducing P. aeruginosa. 90% of VM errors were observed in ESBL strains. Antibiotics discrepancies were: 30% cefepime, 21% aztreonam, 21% piperacillin-tazobactam, 19% ceftriaxone, 17% cefotaxime, 12% ceftazidime, 6% meropenem, and 2% imipenem. Well-defined resistant strains are useful to study the susceptibility testing proficiency.

Publication Types:

• Meeting Abstracts

Keywords:

• Anti-Bacterial Agents
• Aztreonam
• Cefotaxime
• Cephalosporins
• Enterobacteriaceae
• Laboratories
• Quality Control
• Spain
• Thienamycins
• beta-Lactams
• cefepime
• meropenem

Other ID:

• GWAIDS0029278

UI: 102268910

From Meeting Abstracts