Article

The Role of Patient-to-Patient Transmission in the Acquisition of Imipenem-Resistant Pseudomonas aeruginosa Colonization in the Intensive Care Unit

Department of Pathology, Institute of Genomic Sciences, University of Maryland School of Medicine, 10 South Pine Street, Baltimore, MD 21201, USA.
The Journal of Infectious Diseases (Impact Factor: 5.78). 09/2009; 200(6):900-5. DOI: 10.1086/605408
Source: PubMed

ABSTRACT Imipenem-resistant Pseudomonas aeruginosa (IRPA) is an emerging problem. The causal role of antibiotic selective pressure versus patient-to-patient transmission has not been assessed using a large cohort.
Patients who were admitted to the medical and surgical intensive care units (ICUs) at the University of Maryland Medical Center from 2001 through 2006 had multiple perianal culture samples collected. Using pulsed-field gel electrophoresis (PFGE), the number of patients who acquired IRPA as a result of patient-to-patient transmission was determined. We also analyzed a subset of patients who had a previous surveillance culture that grew an imipenem-susceptible P. aeruginosa (ISPA) and a subsequent culture that grew IRPA.
Our cohort consisted of 7071 patients. Three hundred patients were colonized with IRPA. 151 patients had positive culture findings at ICU admission, and 149 patients acquired an IRPA. Among the patients who acquired IRPA, 46 (31%) had a PFGE pattern similar to that for another isolate, and 38 (26%) were found to be colonized with an ISPA on the basis of earlier culture results. Of the 38-patient subset, 28 (74%) had identical PFGE patterns.
Our data showed that, of those cases of IRPA acquisition, 46 (31%) were defined as cases of patient-to-patient transmission, and 28 (19%) were cases of acquisition by the patients' endogenous flora.

0 Followers
 · 
74 Views
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Critically ill patients with infection in the intensive care unit (ICU) would certainly benefit from timely bacterial identification and effective antimicrobial treatment. Diagnostic techniques have clearly improved in the last years and allow earlier identification of bacterial strains in some cases, but these techniques are still quite expensive and not readily available in all institutions. Moreover, the ever increasing rates of resistance to antimicrobials, especially in Gram-negative pathogens, are threatening the outcome for such patients because of the lack of effective medical treatment; ICU physicians are therefore resorting to combination therapies to overcome resistance, with the direct consequence of promoting further resistance. A more appropriate use of available antimicrobials in the ICU should be pursued, and adjustments in doses and dosing through pharmacokinetics and pharmacodynamics have recently shown promising results in improving outcomes and reducing antimicrobial resistance. The aim of multidisciplinary antimicrobial stewardship programs is to improve antimicrobial prescription, and in this review we analyze the available experiences of such programs carried out in ICUs, with emphasis on results, challenges, and pitfalls. Any effective intervention aimed at improving antibiotic usage in ICUs must be brought about at the present time; otherwise, we will face the challenge of intractable infections in critically ill patients in the near future.
    Infection and Drug Resistance 10/2014; 7:261-71. DOI:10.2147/IDR.S44357
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We aimed to develop a new approach to the analysis of antimicrobial resistance data from the hospitals, which allows simultaneous analysis of both individual- and population-level determinants of bacterial resistance. This was a retrospective cohort study that included adult patients who stayed in the hospital >2 days. We analyzed data using shared frailty Cox models and tested our approach using a priori hypotheses based on biology and epidemiology of antibiotic resistance. For gram-negative bacteria, the use of the major selecting antibiotic by an individual was the main risk factor for acquiring resistant species. Hazard ratios (HRs) were strikingly high for ceftazidime-resistant Enterobacter species (HR=11.17; 95% confidence interval [CI]: 5.67-22.02), ciprofloxacin-resistant Pseudomonas aeruginosa (HR=4.41; 95% CI: 2.14-9.08), and imipenem-resistant P. aeruginosa (HR=7.92; 95% CI: 4.35-14.43). Ward-level use was significant for vancomycin-resistant enterococci (VRE) (HR=1.40; 95% CI: 1.07-1.83) and for imipenem-resistant P. aeruginosa (HR=1.40; 95% CI: 1.08-1.83). Previous incidence of infection in the same ward increased the risk of acquiring methicillin-resistant Staphylococcus aureus (HR=1.22; 95% CI: 1.15-1.30) and VRE (HR=1.53; 95% CI: 1.38-1.70). Our results were consistent with our hypotheses and showed that combining population- and individual-level data is crucial for the exploration of antimicrobial resistance development.
    Microbial drug resistance (Larchmont, N.Y.) 07/2014; DOI:10.1089/mdr.2013.0173 · 2.52 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The IncA/C plasmids have been implicated for their role in the dissemination of β-lactamases including gene variants that confer resistance to third generation cephalosporins, which are often the treatment of last resort against multidrug resistant hospital-associated pathogens. A blaFOX-5 gene was detected in 14 E. coli and 16 Klebsiella isolates that were cultured from perianal swabs of patients admitted to an intensive care unit (ICU) of the University of Maryland Medical Center (UMMC) in Baltimore, Maryland over a span of three years. Four of the FOX-encoding isolates were obtained from subsequent samples of patients that were initially negative for an AmpC β-lactamase upon admission to the ICU, suggesting the AmpC β-lactamase encoding plasmid was acquired while in the ICU. The genomes of five E. coli isolates and six Klebsiella isolates containing blaFOX-5 were selected for sequencing based on their plasmid profiles. An ∼167-kb IncA/C plasmid encoding the FOX-5 β-lactamase, a CARB-2 β-lactamase, additional antimicrobial resistance genes, and heavy metal resistance genes was identified. Another FOX-5 encoding IncA/C plasmid that was nearly identical except for a variable region associated with the resistance genes was also identified. To our knowledge, these plasmids represent the first FOX-5-encoding plasmids sequenced. We used comparative genomics to describe the genetic diversity of a FOX-5 β-lactamase-encoding plasmid relative to the whole-genome diversity of 11 E. coli and Klebsiella isolates that carry this plasmid. Our findings demonstrate the utility of whole genome sequencing for tracking of plasmid and antibiotic resistance gene distribution in healthcare settings.
    Antimicrobial Agents and Chemotherapy 06/2014; 58(8). DOI:10.1128/AAC.02573-14 · 4.45 Impact Factor

Preview

Download
0 Downloads
Available from