Antimicrobial resistance and inducible beta-lactamase synthesis in Pseudomonas aeruginosa strains isolated from nosocomial infections of various localizations

Pseudomonas aeruginosa (P. aeruginosa) is a major opportunistic pathogen associated with nosocomial infections. The intrinsic resistance of P. aeruginosa to many antibiotics and the ability of P. aeruginosa to rapidly acquire resistance make the management of infections difficult. This study aimed to evaluate the antibiotic resistance profiles and inducible beta-lactamase (ibl) synthesis in P. aeruginosa strains isolated from hospitalized patients at the Azerbaijan Medical Faculty Hospital. This study included 125 samples including 44 sputum samples from pneumonia patients, 44 urine samples from individuals with urinary tract infections, and 41 postoperative samples encompassing pus, drainage, and abscess contents derived from surgical site infections. P. aeruginosa was isolated by conventional culture methods and drug susceptibility and ibl synthesis were investigated by disc diffusion. Fisher's exact test compared the ibl synthesis of P. aeruginosa strains isolated from different infection sources. Statistical significance was accepted as 0.05 (p≤0.05). Of 26 P. aeruginosa, 19 (73.1%) were resistant to ceftazidime, 20 (76.9%) to cefepime, 20 (76.9%) to piperacillin and 23 (88.4%) to aztreonam, while 19 (73.1%) were susceptible to imipenem, 19 (73.1%) to amikacin, 23 (76.9%) to piperacillin and 23 (88.4%) to colistin. In addition, the ibl synthesis (+) P. aeruginosa strains isolated from pneumonia patients (77.8%) were marginally significantly higher than those isolated from urinary tract infections (25.0%) (p=0.057). Our results reveal high rates of antibiotic resistance among P. aeruginosa strains isolated from patients in our hospital, particularly against several key antibiotics. We recommend larger studies involving multiple centers and various sample types.