Clinical Microbiology and Antimicrobial Chemotherapy. 2023; 25(2):179-186
To analyse aggregated AST results for key microorganisms collected through the 2022 reports of chief specialists in clinical microbiology and antimicrobial resistance.
The study included an analysis of the interpretation criteria used in the laboratories and an evaluation of the AST reports. Data were obtained from the clinical microbiology and antimicrobial resistance annual reporting system. Reports were analyzed using EUCAST guidelines for expected resistance phenotypes and expected susceptible phenotypes. Data processing and analysis were realized using the «R» programming language. The 95% CI for the percentages of inaccuracies/errors distributed by federal districts was calculated using the Wilson method.
A combination of several interpretation standards was used in 27.78% of laboratories, MUK 4.2.1890-04 was noted as one of the options in 57.6% of laboratories. Irrelevant standards of interpretation with a lag of 1 year or more were used in a significant number of cases. The highest percentage of errors/ inaccuracies by the type «expected resistance» was observed for A. baumannii – 14,06% (N = 9163), E. faecium – 8,05% (N = 3451) and S. pneumoniae – 6,18% (N = 2779). «Susceptibility categorization in the absence of interpretive breakpoints» was highest for S. aureus – 13.24% (N = 19784) and S. pneumoniae – 8.76% (N = 3942). Rare phenotype was determined in the highest percentage in relation to S. pneumoniae and antimicrobials: vancomycin – 54.04% and linezolid – 64.6%.
The study revealed a significant number of errors/inaccuracies in the data reported. The use of irrelevant interpretation criteria, the exclusion of situations with rare phenotypes and expected resistance, may contribute to a significant increase in the likelihood of inappropriate antibacterial prescribing.