Rate of Isolation and Trends of Antimicrobial Resistance of Multidrug Resistant Pseudomonas Aeruginosa from Otorrhea in Chronic Suppurative Otitis Media

OBJECTIVES To assess the rate of isolation of Pseudomonas aeruginosa (PA) and multidrug-resistant PA (MDR-PA) from patients with chronic suppurative otitis media (CSOM) otorrhea and the annual trend of antibiotic-resistance. METHODS Otorrhea samples were collected aseptically from 1,598 CSOM patients. The rate of bacterial isolation and the results of antibiotic susceptibility testing were evaluated retrospectively. RESULTS The PA isolation rate from CSOM otorrhea was 24.4%. Of the 398 isolated strains tested for their susceptibilities to 10 antibiotics, 395 strains showed definitive results. Of these, 183 (46.3%) were susceptible to whole antibiotics and 212 (53.7%) was resistant to more than 1 antibiotics, with the frequency of antibiotics-resistance increasing significantly over time. Although strains susceptible to all antibiotics decreased over time, the rate of isolation of MDR-PA did not change significantly. Resistance to aminoglycosides and quinolones was higher than to other antibiotics and significantly increased over time, whereas resistance to other antibiotics showed no trend. CONCLUSION MDR-PA, assessed using five individual antibiotics and six antibiotic-classes, showed no tendency to increase or decrease over time. This may have been due to increased concern about antibiotic-resistant bacterial strains, leading to improved infection control within hospitals and healthcare centers.