Pathogens of Intensive Care Unit-Acquired Infections and Their Antimicrobial Resistance: A 9-Year Analysis of Data from a University Hospital

  Pathogens surveillance and antimicrobial resistance are essential for the prompt organization of therapeutic and preventive actions in healthcare settings. We investigated the causative agents of intensive care unit (ICU)-acquired infections and their antimicrobial resistance in a university hospital over a nine-year period. An active, prospective surveillance was conducted in the ICUs of a tertiary care hospital between 2007 and 2015. The changing patterns in the frequency of pathogens and their antimicrobial resistance by the time were statistically evaluated with Mann-Whitney U test. A total of 3044 pathogens were isolated from 4272 healthcare-associated infections attacks in 3437 patients. The most frequently detected organisms were Acinetobacter spp. (n = 1060, 34.8%), Pseudomonas aeruginosa (n = 622, 20.4%), Escherichia coli (n = 340, 11.1%), Klebsiella pneumoniae (n = 331, 10.8%), and Candida spp. (n = 285, 9.3%). Carbapenem resistance among Acinetobacter spp., P. aeruginosa, E. coli, and K. pneumoniae was found as 82%, 30.7%, 2%, and 9.3%, respectively. The prevalence of extended-spectrum beta-lactamase (ESBL) among E. coli and K. pneumoniae was 49.7% and 41.3%, orderly, and methicillin resistance in Staphylococcus aureus was 81.8%. Substantial reductions occurred in the rates of E. coli (16.8% to 8.9%), S. aureus (11% to 3.2%), coagulase-negative staphylococci (7.9% to 0), and Stenotrophomonas maltophilia (4.2% to 0.3%) during the study period by the applied infection control measures while the rate of Acinetobacter spp. (9.7% to 51%) significantly increased. Furthermore, the increases in the carbapenem resistance among Acinetobacter spp. (52.5% to 91.4%), Pseudomonas spp. (25.7% to 51.6%), E. coli (0 to 12.7%), and K. pneumoniae (2.6% to 9%) and the decrease in the prevalence of ESBL-producing E. coli (57% to 27.2%) were statistically significant. Despite the decreases in the frequencies of staphylococci and some Gram-negative bacteria, the current infection control measures have been unable to limit the spread of carbapenem-resistant Gram-negative bacteria in our facility. Additional precautions are required to control such pathogens in the intensive care units