Microbiological External Quality Assurance Program (MEQAO)--evaluation of results obtained in 2001 of sanitary-epidemiological station laboratories

The aim of this study was to evaluate reliability of identification and determination of sensitivity to antibiotics and chemotherapeutics of some Enterobacteriaceae strains in 49 sanitary-epidemiological stations. All laboratories engaged in this study received 4 strains each (S. marcescens phenotype ESBL+, K. pneumoniae phenotype ESBL+, S. Typhimurium and S. Newport) previously identified in the Department of Bacteriology of National Institute of Hygiene. The laboratories included in the survey were asked to determine the genus (serovar) of each control strain using the lowest number of biochemical test recommended by Institute and to determine of the sensitivity of the identified strains to antibiotics in accordance with the guidelines of the NCCLS and domestic recommendations. Only in 2 participating laboratories the identification of one of studied strains (K. pneumoniae) was completely bad and in 9 laboratories the serological identification of S. Newport was incomplete or serological type was not correctly recognised. In the determination of the sensitivity of the control strains to chemotherapeutic agents abnormalities were found in the technique of antibiogram and test for ESBL performing and incorrect selection of disc for antibiograms as well as erroneous interpretation of the results.