الفهرس | Only 14 pages are availabe for public view |
Abstract P. aeruginosa is a leading nosocomial pathogen with a worrisome increase in antimicrobial resistance. Infections caused by multidrug-resistant (MDR) and extensively drug-resistant (XDR) P. aeruginosa are major health threats due to limited susceptibility to available therapeutic options. Ceftolozane/tazobactam (C/T) and ceftazidime/avibactam (CAV/AVI), two novel combinations of cephalosporins and β lactamase inhibitors were recently approved for treatment of multidrug-resistant Gram-negative pathogens. This study was performed at the Medical Microbiology and Immunology Department, Faculty of Medicine, Menoufia University with the main objectives to study different resistance mechanisms contributing to MDR and XDR P. aeruginosa phenotypes and to assess their biofilm-forming ability by the corresponding phenotypic methods. Additionally, the role of efflux pump-mediated colistin resistance and the presence of type III secretion system exotoxins genes (exotoxin U & exotoxin S) in MDR/XDR P. aeruginosa isolates were explored. A major goal of the current study was to assess the in vitro activity of the second generation β-lactam/beta-lactamases inhibitor combinations; C/T and CAV/AVI against MDR/XDR P. aeruginosa isolates expressing variable resistance and virulence traits from patients with hospital-acquired infections (HAIs) at Menoufia University Hospitals (MUHs).Also, to detect the synergistic activity of CAZ/AVI plus aztreonam (ATM) combination against MβL producers. This study was conducted during the period from May 2021 to November 2022 involving a total of 313 hospitalized patients (210 males and 103 females with a mean age of 44.13 ±18.38 years). selected patients were admitted to different departments and ICUs of MUHs with different types of infections that became evident 48 hours or more after hospital admission. A total of 80 P. aeruginosa isolates were obtained from the different clinical samples. P. aeruginosa infections were more common among males (60.2%), patients aged from 18-60 years (58.8%), smokers (75%), who stayed in hospitals from 7 to 14 days (62.4%), used antibiotics (100%), exposed to invasive procedures (100%) and had associated co-morbidities (71.3%). About 41.2% (33/80) of P. aeruginosa isolates were obtained from ICUs. The highest rate of P. aeruginosa isolation was from urine (22/80; 27.5%). Antimicrobial susceptibility screening revealed high resistance rates to various antibiotics against P. aeruginosa isolates. About 75% of P. aeruginosa isolates were resistant to gentamicin followed by resistance rates of 73.8%, 73.8%, 70%, 68.7%, 67.5% and 66.3% for ceftazidime, tobramycin, imipenem, doripenem, meropenem and cefepime respectively. About 63.7%, 58.7%, 57.5%, 52.4%, 50% of P. aeruginosa were also resistant to aztreonam, piperacillin, amikacin, levofloxacin and ciprofloxacin respectively. However, a significant proportion remaiSqned susceptible to ceftazidime-avibactam, ceftolozane-tazobactam and fosfomycin (81.3%, 63.7% & 62.5%, respectively). The prevalence of MDR, XDR and non-MDR phenotypes among P. aeruginosa isolates was 32.5%, 52.5% and 15%, respectively. None of the obtained P. aeruginosa isolates proved PDR phenotype. ESβL production was confirmed in 12.5% of P. aeruginosa isolates using the cephalosporin/clavulanate combination disk test. Also, AmpC production was confirmed in 46.25% of isolates by AmpC disk confirmatory test. |