The Antibiotic Resistance Profile of Pseudomonas Aeruginosa in a Tertiary Medical Center from Malaysia

Abstract

Background: Pseudomonas aeruginosa is a notorious gram-negative bacterium that has become a global public health concern owing to the emergence of multi- and pandrug-resistant strains. This study sought to determine the antibiotic susceptibility profile of P. aeruginosa in a tertiary medical center from Malaysia. Materials and Methods: Each isolate’s identity was confirmed using the VITEK 2 GN kit, and subjected to antibiotic susceptibility testing using the VITEK 2 AST-N374 card (for testing against piperacillintazobactam, ceftazidime, cefepime, imipenem, meropenem, amikacin, gentamicin and ciprofloxacin) and Etest strips (for testing against doripenem and polymyxin B). Isolates which were not susceptible to >1 carbapenem were tested for carbapenemase production using the modified carbapenem inactivation method (mCIM). Results: Out of 102 isolates studied, 64 (62.7%) were fully susceptible to all the antibiotics tested. Twenty-six (25.5%) were resistant to >1 antibiotic from >2 antibiotic classes, and 21 (20.6%) were resistant to >1 antibiotic from >3 classes. Susceptibility was highest with polymyxin B (100%) and lowest with piperacillin-tazobactam (64.7%). Carbapenem susceptibility was between 78.4% to 81.4%. Out of 22 isolates which were not susceptible to >1 carbapenem, 18 (81.8%) were not susceptible to all three carbapenems. Conclusion: More than half of our P. aeruginosa isolates were fully susceptible to all the anti-pseudomonal antibiotics tested. Multidrug-resistant strains accounted for between 20% to 25% of all our P. aeruginosa isolates. Through mCIM testing, carbapenemase production did not appear to be the dominant resistance mechanism.