Article

Acinetobacter baumannii in intensive care unit: A novel system to study clonal relationship among the isolates

Department of Experimental Medicine and Biochemical Sciences, Tor Vergata University of Rome, Via Montpellier 1, 00133 Rome, Italy.
BMC Infectious Diseases (Impact Factor: 2.61). 02/2008; 8:79. DOI: 10.1186/1471-2334-8-79
Source: PubMed

ABSTRACT The nosocomial infections surveillance system must be strongly effective especially in highly critic areas, such as Intensive Care Units (ICU). These areas are frequently an epidemiological epicentre for transmission of multi-resistant pathogens, like Acinetobacter baumannii. As an epidemic outbreak occurs it is very important to confirm or exclude the genetic relationship among the isolates in a short time. There are several molecular typing systems used with this aim. The Repetitive sequence-based PCR (REP-PCR) has been recognized as an effective method and it was recently adapted to an automated format known as the DiversiLab system.
In the present study we have evaluated the combination of a newly introduced software package for the control of hospital infection (VIGI@ct) with the DiversiLab system. In order to evaluate the reliability of the DiversiLab its results were also compared with those obtained using f-AFLP.
The combination of VIGI@ct and DiversiLab enabled an earlier identification of an A. baumannii epidemic cluster, through the confirmation of the genetic relationship among the isolates. This cluster regards 56 multi-drug-resistant A. baumannii isolates from several specimens collected from 13 different patients admitted to the ICU in a ten month period. The A. baumannii isolates were clonally related being their similarity included between 97 and 100%. The results of the DiversiLab were confirmed by f-AFLP analysis.
The early identification of the outbreak has led to the prompt application of operative procedures and precautions to avoid the spread of pathogen. To date, 6 months after the last A. baumannii isolate, no other related case has been identified.

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    • "Acinetobacter baumannii (A. baumannii) is an important opportunistic pathogen responsible for a nosocomial infections, such as pneumonia, urinary tract infections, bacteraemia and meningitis [1] [2] [3] . Its clinical significance is due to its rapid acquisition of a wide variety of antibiotic resistance genes so it has caused difficulties in the control [4] . "
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    • "Rep- PCR libraries can therefore be easily assembled to enable, for example, the comparison of strains over time and probably across laboratories, with a view to charting the epidemiology of isolates. Outbreaks of Acinetobacter baumannii have been extensively studied using DiversiLab rep-PCR typing (Carretto et al., 2008; Fontana et al., 2008; Kohlenberg et al., 2009; Yan et al., 2010; Perez et al., 2010). Using DiversiLab, a snapshot emerged of the global epidemiology of carbapenem-resistant A. baumannii, where it was found that almost half of 492 isolates from a worldwide collection belonged to a single clonal lineage that clustered with European clone II (Higgins et al., 2010; Dijkshoorn et al., 1996). "
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    • "The data on the investigated strain are available at http://www.pubmlst.org/paeruginosa. The DiversiLab system was recently evaluated by several authors for confirming different outbreaks caused by Staphylococcus aureus, Acinetobacter baumannii, Klebsiella spp., or P. aeruginosa (Caretto et al., 2008; Doléans- Jordheim et al., 2009; Fontana et al., 2008; Grisold et al., 2009) or to test the discriminative power of it in the case of known outbreak strains (Grisold et al., 2010; Tenover et al., 2009) in comparison with the PFGE. In most cases, DiversiLab system proved to be a rapid and reliable method for molecular analysis of suspected nosocomial outbreaks cased by methicillin-resistant S. aureus, A. baumannii, and extended-spectrum β-lactamase–producing Klebsiella spp. "
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