Prevalence of MDR, XDR and PDR Phenotypes among Pseudomonas aeruginosa Strains Isolated from Hospitalized Patients in Mazandaran Province, Iran

Background and purpose: Pseudomonas aeruginosa is an opportunistic pathogen and the second leading cause of nosocomial infections, especially in the intensive care unit (ICU), and is responsible for high mortality rates. The aim of this study was to determine the pattern of antibiotic susceptibility and prevalence of multiple drug resistance strains of P. aeruginosa isolated from hospitalized patients in Mazandaran province, Iran 2020. Materials and methods: In this descriptive cross-sectional study, 80 strains of P. aeruginosa were collected from different clinical specimens. Antibiotic susceptibility of the isolates was determined by disk agar diffusion method according to the instructions of Clinical and Laboratory Standards Institute (CLSI). Finally, based on the resistance pattern, multi-drug resistant (MDR), extensive-drug resistant (XDR), and pandrug-resistant (PDR) isolates were identified. Results: Out of 80 P. aeruginosa isolates, the highest number of samples was collected from ICU (58.75%). The highest antibiotic resistance was observed against ticarcillin-clavulanate (95%), meropenem (80%), and ceftazidime (75%). Piperacillin-tazobactam and cefpime showed the highest inhibitory effect against P. aeruginosa isolates with 57.5% and 51.25% sensitivity, respectively. Altogether, 88.75% and 46.25% of the isolates were categorized as MDR and XDR, respectively. In this study, PDR phenotype was not observed among our tested strains. Conclusion: This study showed that P. aeruginosa strains are resistant to a wide range of antibiotics. Given the role of this bacterium in nosocomial infections, especially in ICU, it is necessary to take immediate measures for timely identification, definitive treatment with appropriate antibiotics, and preventing the spread of resistant strains of this bacterium.