ANTIBACTERIAL RESISTANCE PATTERNS AND INCIDENCE OF NOSOCOMIAL PSEUDOMONAS AERUGINOSA BACTEREMIA IN A TERTIARY-CARE EDUCATIONAL HOSPITAL IN TURKEY: A PERSPECTIVE BETWEEN 2001 AND 2019

Background: Pseudomonas aeruginosa (PSA) is one of the most important pathogens causing nosocomial bacteremia in most parts of the world. Objectives: In this study it was aimed to evaluate the resistance patterns and incidence of microbiologically confirmed nosocomial bacteremia (MCNB) related PSA strains between 2001-2019. Methods: Any patient in whom PSA was isolated in at least one set of blood cultures (sent to the bacteriology laboratory 72h after hospital admission) was considered to have microbiologically confirmed NB. Blood cultures were performed on Back/Alert (bioMerieux, Durham, NC). Bacterial identifications were performed by automated API (bioMerieux, Durham, NC). Antibacterial susceptibility tests were evaluated according to Clinical Laboratory Standards Institute (CLSI) criteria until 2014 and EUCAST between 2015 and 2019. Incidence density of PSA MCNB was calculated by using hospital electronic database. Results: A total of 1705 strains of P.aeruginosa fulfilling study inclusion criteria, were isolated during the 19-year study period in the hospital from intensive care units and clinics and included in the study. When the 2001-2002 and 2018-2019 periods were compared, there was a decrease in resistance to meropenem and amikacin (31.1%-20.4% p: 0.025 and 34.3%-22.8% p:0.029). However, the analysis of the resistance patterns of carbapenem-resistant P. aeruginosa strains as a subgroup (2001-2002) vs (2018 vs 2019), ciprofloxacin and cefepime resistance rates increased significantly (58%-79% p:0.0096 and 46%-72% p: 0.026). P. aeruginosa bacteremia rates incidence density rates ranged between 0.11 and 0.30 episodes per thousand hospital day during the study period. Conclusion: During the 19 years there was a significant decrease in amikacin and meropenem resistance while there was a significant increase in the subgroup of carbapenem-resistant strains. More infection control and antimicrobial stewardship efforts are needed to decrease the antibacterial resistance rates and incidence.