EVALUATION OF RESISTANCE PATTERNS OF PRIORITY GRAM-NEGATIVE BACCILI ISOLATED FROM CLINICAL BIOSUBSTRATES

Abstract

Objectives. Antimicrobial resistance is listed among the top ten health threats, according to WHO reports. In addition to the fact that it has already reached alarming proportions in many regions of the world, this phenomenon is constantly increasing, causing enormous social and economic damage. The purpose of the study is to evaluate the resistance profiles of priority Gram-negative bacilli.

Material and methods. An experimental microbiological study was carried out with the examination of a total of 2062 strains of E. coli, K. pneumoniae, A. baumannii and P. aeruginosa isolated from blood, cerebrospinal fluid and urine, during 2022, using the cultural method as well as the Vitek-2 Compact automated system, and the susceptibility testing to antimicrobial preparations was performed by the disc-diffusimetric (KirbyBauer) and automated (Vitek-2 Compact) method. The interpretation of the results was carried out based on the EUCAST standard.

Results. The highest level of resistance of E. coli strains isolated from blood and cerebrospinal fluid was registered to ampicillin/amoxicillin (83.8%), followed by third generation cephalosporins (3.9%). The resistance of K. pneumoniae reached alarming percents to practically all groups of antimicrobials tested: fluoroquinolones (98.7%), aminoglycosides (94.7%), cephalosporins (94.7%), penicillins (93.7%). The resistance structure of P. aeruginosa strains isolated in 2022 was decreasing compared to previous years, but an increased level was still recorded in the carbapenem group (53.3%). Absolutely all strains of A. baumannii were resistant to fluoroquinolones and to carbapenems and aminoglycosides the resistance percent of these strains exceeded 90.0%.

Conclusions. In 2022, a slight decrease in the resistance of the isolated strains is recorded for most of the tested antimicrobials, compared to the years 2020 and 2021, but the situation remains worrisome, because of the high levels of resistance that are found in more than 50% of the researched strains.