title: Gram-negative bacilli causing infections in an intensive care unit of a tertiary care hospital in Istanbul, Turkey.
abstract: BACKGROUND
  This study aimed to demonstrate the changing epidemiology of infecting microorganisms and their long-term resistance profiles and to describe the microbiological point of view in anti-infective management of intensive care unit (ICU) patients.
  
  
  METHODS
  A total of 5,690 isolates of Gram-negative bacilli were included in this study. Antibiotic susceptibility was tested using the disk diffusion method and Vitek 2 system. Chi-square tests were used for hypothesis testing.
  
  
  RESULTS
  The most frequently isolated organisms were A. baumannii (37.3%), P. aeruginosa (30.3%), Enterobacter spp. (10.4%), E. coli (10.4%), and Klebsiella spp. (8.9%). A. baumannii was the most frequently isolated organism from the respiratory tract (43.4%); the susceptibility rates for imipenem and meropenem decreased to 7% and 6% (p < 0.0001), respectively. The percentage of multidrug-resistant (MDR) A. baumannii isolates continuously increased from 18.7% in 2004 to 69% in 2011 (p < 0.0001), whereas MDR P. aeruginosa isolates increased from 1.5% to 22% (p < 0.0001). Carbapenem-resistant Klebsiella isolates emerged in 2010 and increased to 20% in the next year. The rates of ESBL-producing Enterobacteriaceae in the ICU was very high in 2011 - 50% for E. coli and 80% for Klebsiella strains.
  
  
  CONCLUSIONS
  The most common isolated Gram-negative bacillus in our study was A. baumannii and that the prevalence of MDR isolates has increased markedly over. Accordingly, the comparison of antibiotic resistance of other pathogens in 2004 and 2011 displayed an increasing trend. These data imply the urgent need for new and effective strategies in our hospital and in the region.
authors.affiliation: Haydarpasa Numune Education and Research Hospital, Uskudar, Istanbul, Turkey. senihasen@gmail.com.
authors.forename: Seniha
authors.initials: S
authors.lastname: Senbayrak Akcay
authors.forename: Asuman
authors.initials: A
authors.lastname: Inan
authors.forename: Simin
authors.initials: S
authors.lastname: Cevan
authors.forename: Ayse Nilufer
authors.initials: AN
authors.lastname: Ozaydın
authors.forename: Naz
authors.initials: N
authors.lastname: Cobanoglu
authors.forename: Seyfi Celik
authors.initials: SC
authors.lastname: Ozyurek
authors.forename: Sebahat
authors.initials: S
authors.lastname: Aksaray
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D024901:Drug Resistance, Multiple, Bacterial; D006090:Gram-Negative Bacteria / Q000145:classification* / Q000187:drug effects* / Q000302:isolation & purification; D016905:Gram-Negative Bacterial Infections / Q000453:epidemiology* / Q000382:microbiology*; D006801:Humans; D007362:Intensive Care Units; D008826:Microbial Sensitivity Tests; D015995:Prevalence; D062606:Tertiary Care Centers; D014421:Turkey / Q000453:epidemiology
chemical_list: D000900:Anti-Bacterial Agents