Surveillance Cultures and Duration of Carriage of Multidrug-Resistant Acinetobacter baumannii

Division of Epidemiology, Tel-Aviv Sourasky Medical Center, 6 Weizmann St., Tel-Aviv 64239, Israel.
Journal of Clinical Microbiology (Impact Factor: 3.99). 05/2007; 45(5):1551-5. DOI: 10.1128/JCM.02424-06
Source: PubMed


Isolating carriers of multidrug-resistant (MDR) Acinetobacter baumannii is the main measure to prevent its spread. Identification of carriers accompanied by contact precautions is essential. We aimed to determine the appropriate surveillance sampling sites and the duration of carriage of MDR A. baumannii. We studied prospectively two groups of patients from whom MDR A. baumannii was previously isolated: (i) those with recent clinical isolation (<or=10 days) and (ii) those with remote clinical isolation (>or=6 months). Screening for carriage was conducted from six sites: nostrils, pharynx, skin, rectum, wounds, and endotracheal aspirates. Strains recovered concurrently from different sites were genotyped using pulsed-field gel electrophoresis. Twelve of 22 with recent clinical isolation of MDR A. baumannii had >or=1 positive screening culture, resulting in a sensitivity of 55% when six body sites were sampled. Sensitivities of single sites ranged from 13.5% to 29%. Among 30 patients with remote clinical isolation, screening cultures were positive in 5 (17%), with a mean duration of 17.5 months from the last clinical culture. Remote carriers had positive screening cultures from the skin and pharynx but not from nose, rectum, wounds, or endotracheal aspirates. Eleven strains from five patients were genotyped. In all but one case, isolates from different sites in a given patient were clonal. Current methodology is suboptimal to detect MDR A. baumannii carriage. The sensitivity of surveillance cultures is low, even when six different body sites are sampled. The proportion of individuals with previous MDR A. baumannii isolation who remain carriers for prolonged periods is substantial. These data should be considered when designing measures to limit the spread of MDR A. baumannii.

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Available from: Dror Marchaim, Jan 27, 2014
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    • "The primary reason that A. baumannii is successful as a human pathogen is due to its multidrug resistance, which is generally assimilated by acquisition of various genetic elements such as plasmids , insertion sequences and resistance islands (Dijkshoorn et al., 2007; Gordon & Wareham, 2010; Imperi et al., 2011). The other features that render this pathogen successful are its ability to resist desiccation, which allows the pathogen to persist on abiotic surfaces present in healthcare settings, and to colonize asymptomatically within the human host, enabling its rapid spread (Fournier et al., 2006; Jawad et al., 1998; Marchaim et al., 2007; Wendt et al., 1997). "
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    ABSTRACT: Acinetobacter baumannii is an emerging nosocomial pathogen involved in a variety of infections ranging from minor soft-tissue infections to more severe infections such as ventilator-associated pneumonia and bacteremia. A. baumannii has become resistant to most of the commonly used antibiotics and multidrug resistant isolates are becoming a severe problem in the healthcare setting. In the past few years, whole genome sequences of over 200 A. baumannii isolates have been generated. Several methods and molecular tools have been used for genetic manipulation of various Acinetobacter spp. Here we review recent developments of various genetic tools used for modification of A. baumannii genome including various ways to inactivate gene function, chromosomal integration and transposon mutagenesis.
    Preview · Article · May 2015 · Journal of Medical Microbiology
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    • "A second limitation is that environmental contamination was not evaluated at that time, although it may have played a role in the observed results (15-18). Additionally, surveillance cultures may not provide adequate sensitivity (19). In our study, we used cultures collected at three different sites to increase sensitivity. "
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    ABSTRACT: To determine factors associated with colonization by carbapenem-resistant Pseudomonas aeruginosa and multiresistant Acinetobacter spp. Surveillance cultures were collected from patients admitted to the intensive care unit at admission, on the third day after admission and weekly until discharge. The outcome was colonization by these pathogens. Two interventions were implemented: education and the introduction of alcohol rubs. Compliance with hand hygiene, colonization pressure, colonization at admission and risk factors for colonization were evaluated. The probability of becoming colonized increased during the study. The incidence density of colonization by carbapenem-resistant P. aeruginosa and multiresistant Acinetobacter spp. and colonization pressure were different between periods, increasing gradually throughout the study. The increase in colonization pressure was due to patients already colonized at admission. The APACHE II score, colonization pressure in the week before the outcome and male gender were independent risk factors for colonization. Every 1% increase in colonization pressure led to a 2% increase in the risk of being colonized. Colonization pressure is a risk factor for carbapenem-resistant P. aeruginosa and multiresistant Acinetobacter spp. colonization. When this pressure reaches critical levels, efforts primarily aimed at hand hygiene may not be sufficient to prevent transmission.
    Full-text · Article · Aug 2013 · Clinics (São Paulo, Brazil)
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    • "While long-term carriage of MDR A. baumannii has been reported [4], this is the first study to quantify the duration of carriage of this organism in ICUs. Our data suggest that, at least in non-outbreak settings, importation by patients who were colonized elsewhere constitutes the main source of this organism in ICUs and thus screening cultures on admission are likely to be more cost-effective than subsequent screening cultures. "

    Preview · Article · Jun 2012 · Infection Control and Hospital Epidemiology
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