Latin-American External Quality Assurance System (LA-EQAS): Three Years of Experience

CORSO A; CERIANA P; LEARDINI N; MIRANDA M; GALAS M

Chicago, USA

Congreso; 43rd Interscience Conference of Antimicrobial Agents and Chemotherapy; 2003

Through the Project for Prevention and Control of Antimicrobial Resistance in the Americas, PAHO/WHO designated in 200, the Antimicrobial Division of INEI, Argentina, as Reference Laboratory and Program Coordinator of the LA-EQAS. The main goal of the program is to assist laboratories in improving the quality of microcrobilogical testing through training courses, standard operating procedures and an EQAS. The program began with eight labs from seven countries: Bolivia, Ecuador (2 labs), El Salvador, Guatemala, Nicaragua, Paraguay and Peru, and in 2002 four additional countries were included: Costa Rica, Honduras, Panama, and the Dominican Republic. Six panels of ten unknown strains each were distributed to participants. Laboratories were evaluated for: 1) bacterial identification; 2) susceptibility test measurements (inhibition zones); and 3) susceptibility test interpretation. Among the six panels, correct identification was about 80 %. Most labs were able to detect methicillin resistance in S. aureus ans. S. epidermidis. Laboratories were able to detect high and moderate levels of vancomycin resistance in E faecium, but there were several errors in reporting intrinsic resistance in E gallinarum. There were several errors in detecting ESBL-production in Enterobacteriaceae, with many labs failing to change the results for all tested cephalosporins from susceptible to resistance. The inducible MLSB phenotype in S aureus was also difficult to detect, reported by most labs as clindamycin susceptible. Despite these difficulties, there was overall more than 90% agreement with the expected interpretation categories and improvement in concordance with the reference ranges of inhibition zones. These results demonstrate the need for further training to increase the accuracy of clinical reports and surveillance datain the Americas.