Abstract
Acinetobacter baumannii is an opportun-istic nosocomial pathogen and one of the six most important multidrug-resistant microorganisms in intensive care units (ICU). The aim of this study was to determine the prevalence of antimicrobial resistant A. baumannii strains in ICU. We analysed antibiotic susceptibility of A. baumannii isolates collected in University Hospital Centre Zagreb over a four-year period (2011-2014) based on the hospital computer system data (BIS). The data were interpreted according to Clinical and Lab-oratory Standards Institute criteria.All strains from 2014 were found to be resistant to meropenem, which is a sig-nificant increase when compared to 1.4% in 2011 and 81.8% in 2012. The resistance rate to imipenem increased to 95.8% in 2014 from 91.4% in 2011 and 81.8% in 2012. Colistin resistance, confirmed by E test, was found only in one strain in 2013. The resistance rates of other antimicrobial agents were as follows: ampicillin/sulbac-tam 8.6% and 73.9%, netilmicin 70.6% and 83.3%, gentamicin 48.6% and 91.7%, ami-kacin 82.4% and 80.0% and ciprofloxacin 100% and 100% in 2011 and 2014 respec-tively.Our data confirmed a multidrug-resist-ance phenotype in Acinetobacter bauman-nii strains isolated in ICU at the Clinical Hospital Centre, with a significant increase in resistance rates between 2011 and 2014 against certain antimicrobial agents in-cluding ampicilin/sulbactam and carbap-enems.
Highlights
Acinetobacter spp. are glucose non-fermenting, non-motile, catalase positive, and oxidase negative aerobic gram-negative cocobacilli. [1] The most important species in human medicine is Acinetobacter baumannii
The total number of patients hospitalized in the department in the study period (2011-2014) was as follows: 589, 590, 590, 562, while the number of patients with A. baumannii isolates was 50, 20, 47, 37 in 2011, 2012, 2013 and 2014 respectively
The largest number of A. baumannii isolates originated from respiratory tract specimens during the whole four-year study period
Summary
Acinetobacter spp. are glucose non-fermenting, non-motile, catalase positive, and oxidase negative aerobic gram-negative cocobacilli. [1] The most important species in human medicine is Acinetobacter baumannii. [1] The most important species in human medicine is Acinetobacter baumannii. It is nowadays the leading causative agent of health care associated infections and is often called Gram-negative MRSA. Additional risk factors include recent surgery, central vascular catheterization, tracheostomy, mechanical ventilation, enteral feedings, and treatment with third generation cephalosporin, fluoroquinolones, or carbapenem antibiotics. Many factors contributed to the virulence of Acinetobacter species: survival in dry and iron-deficient conditions for a long period of time, the production of a polysaccharide capsule that works with the cell wall liposaccharide to prevent complement activation. Most A. baumannii isolates are highly resistant to most antibiotics available in clinical practice due to intrinsic and acquired resistance mechanisms. A number of resistance mechanisms to many classes of antibiotics are known to exist in A. baumanni, including β-lactamases production ( carbapenemases), upregulated efflux pumps, production of aminoglycosidemodifying enzymes, permeability defects and the alteration of target sites. [1] The spread of multidrug resistance determinants in A. baumannii occurs by conjugation, transposon acquisition or integron mobilization to gain clusters of genes encoding resistance to several antibiotics families.[5]
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