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

Carla Fontana,Silvia Minelli,Marco Favaro,Gian Piero Testore,Maria Cristina Bossa,Cartesio Favalli,Silvia Natoli,Francesca Leonardis

doi:10.1186/1471-2334-8-79

Carla Fontana, Silvia Minelli + Show 6 more

Open Access

https://doi.org/10.1186/1471-2334-8-79

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Abstract

BackgroundThe 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.MethodsIn 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.ResultsThe 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.ConclusionThe 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.

Highlights

The nosocomial infections surveillance system must be strongly effective especially in highly critic areas, such as Intensive Care Units (ICU)
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
The microorganism first appeared in October 2005, and from that time it was responsible of an epidemic cluster consisting of 56 strains isolated from 13 patients admitted to the medical ICU

Summary

Introduction

The nosocomial infections surveillance system must be strongly effective especially in highly critic areas, such as Intensive Care Units (ICU). Acinetobacter infections are influenced by various risk-factors: the use of medical devices (such as: endotracheal tubes, intravascular and urinary catheters), the exposure to broad-spectrum antibiotics and the type of ward where a patient is admitted (e.g. in ICUs the infection rate is often high) [3,4]. The sum of these factors contributes to sudden outbreaks that are difficult to control and prevent. In order to validate the system the results of the DiversiLab were compared with those obtained by using f-AFLP assay

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Conclusion