Surveillance of Antimicrobial Resistance among Bacterial Pathogens Isolated from Hospitalized Patients at Chiang Mai University Hospital, 2006-2009

Background: Conducting surveillance of multidrug-resistant organisms leads to identifying changes in the pathogens causing healthcare-associated infections (HAIs) of specific sites, and the antimicrobial susceptibility patterns. This surveillance study aimed to characterize the pattern of nosocomial multidrug-resistant pathogens. Methods: Clinical laboratory reports from Chiang Mai University hospital were reviewed from 2006 to 2009. Results: During the 4-year period, gram-negative bacteria were the majority of clinical isolates. A. baumannii was the most common pathogen isolated from sputum. E. coli was the most common pathogen isolated from blood and urine. Carbapenem resistance among A. baumanii isolates was 67.1%, 74.2%, 68.9%, and 74.2% in 2006, 2007, 2008, and 2009, respectively. Carbapenem resistance among P. aeruginosa was 35.0%, 33.8%, 27.0%, and 26.8% in 2006, 2007, 2008, and 2009, respectively. Extended-spectrum βlactamase producing strains accounted for 35.2% and 49.2% among E. coli and K. pneumoniae, respectively in 2006 and 53.2% and 56.5% in 2009. Gram-positive bacteria accounted for 25% of all isolates for all 4 years. S. aureus and Enterococci were the most common gram-positive pathogens. Among S. aureus, 35% and 44% were methicillin-resistant strains in 2006 and 2009, respectively. Conclusions: The surveillance data showed that gram-negative bacteria are the major problems in our hospital. Multidrug-resistant Acinetobacter baumannii is a particularly important problem. Continued surveillance is essential to monitor the trend of these multidrug-resistant bacteria. (J Infect Dis Antimicrob Agents 2011;28:35-44.) Department of Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand. Received for publication: January 4, 2001. Reprint request: Romanee Chaiwarith, Department of Medicine, Faculty of Medicine, Chiang Mai University, Chiang Mai 50200, Thailand. E-mail: [email protected]