Antibiotic resistance profile of Pseudomonas aeruginosa strains isolated from blood culture of patients in intensive care units

• Published in: Journal of critical care 2024-06, Vol.81, p.154709, Article 154709
• Main Authors: Uyar, Neval Yurttutan, Ayaş, Meltem, Kocagöz, Ayşe Sesin
• Format: Article
• Language: English
• Subjects: Antibiotics; Automation; Blood culture; Drug resistance; Infections; Intensive care; Intensive care units; Pseudomonas aeruginosa
• ISSN: 0883-9441; 1557-8615
• DOI: 10.1016/j.jcrc.2024.154709

Infections caused by Pseudomonas aeruginosa are especially prevalent among patients in intensive care units (ICUs). Furthermore, bloodstream infections caused by P. aeruginosa are serious conditions that result in significant patient mortality as well as healthcare costs. Therefore it is important to determine the antibiotic susceptibilities of the agents that cause bloodstream infections in order to be able to guide the clinician in the formulation of a correct and appropriate empirical treatment plan. The aim of this study was to investigate the resistance rates of P. aeruginosa growth in blood cultures of hospitalized patients in our intensive care units. Total of 529 P. aeruginosa strains isolated from blood culture samples sent from ICUs to microbiology laboratory in a ten years (January 2013–April 2023) span, were included in the study. Blood cultures were incubated in the BD BACTEC FX 200 (Becton Dickinson, US) automated blood culture system. Bacterial identification was performed using MALDI TOF MS (Bruker, Germany), and susceptibility testing was performed by Vitek 2 compact (bioMérieux, France) automated system and also using conventional methods according to CLSI (Clinical and Laboratory Standards Institute Standards) and EUCAST (European Committee on Antimicrobial Susceptibility Testing) guidelines. The following antibiotics were tested: amikacin, ceftazidime, ciprofloxacin, gentamicin, cefepime, imipenem, meropenem, piperacillin-tazobactam. Additionally colistin and ceftazidime-avibactam which are preferred in treatment for multi-resistant strains were tested in the study. Colistin susceptibility tests were performed in 433 of 529 isolates both Vitek 2 compact and broth microdilution test. Ceftazidime–avibactam susceptibility tests were performed for 217 of 529 isolates by using disk diffusion method. Highest resistance percentage among P. aeruginosa strains was to imipenem with 50.2% rate. Followed by Meropenem (37.6%), ciprofloxacin (35.7%), ceftazidime (33.4%), piperacillin-tazobactam (31.6%), cefepime (31.6%), gentamicin (19.3%), and amikacin (19.1%). Among 433 isolates, 44 (10, 2%) were defined as colistin resistant. Ceftazidime-avibactam resistance was detected in 42 of 217 (19, 4%) tested strains. Antibiotic susceptibility profiles of the strains are shown in Table 1. Due to the high antibiotic resistance rates of P. aeruginosa isolates in ICUs, infection control measures and antibiotic stewardship program needs to be increased, and eac