Application of Molecular Techniques to the Study of Hospital Infection

Abstract

SUMMARY Nosocomial infections are an important source of morbidity and mortality in hospital settings, afflicting an estimated 2 million patients in United States each year. This number represents up to 5% of hospitalized patients and results in an estimated 88,000 deaths and 4.5 billion dollars in excess health care costs. Increasingly, hospital-acquired infections with multidrug-resistant pathogens represent a major problem in patients. Understanding pathogen relatedness is essential for determining the epidemiology of nosocomial infections and aiding in the design of rational pathogen control methods. The role of pathogen typing is to determine whether epidemiologically related isolates are also genetically related. To determine molecular relatedness of isolates for epidemiologic investigation, new technologies based on DNA, or molecular analysis, are methods of choice. These DNA-based molecular methodologies include pulsed-field gel electrophoresis (PFGE), PCR-based typing methods, and multilocus sequence analysis. Establishing clonality of pathogens can aid in the identification of the source (environmental or personnel) of organisms, distinguish infectious from noninfectious strains, and distinguish relapse from reinfection. The integration of molecular typing with conventional hospital epidemiologic surveillance has been proven to be cost-effective due to the associated reduction in the number of nosocomial infections. Cost-effectiveness is maximized through the collaboration of the laboratory, through epidemiologic typing, and the infection control department during epidemiologic investigations.

Interlaboratory reproducibility of DiversiLab rep-PCR typing and clustering of Acinetobacter baumannii isolates

“…A plethora of molecular methods are available to investigate the epidemiology of bacteria (Li et al, 2009;Singh et al, 2006). DiversiLab, which is one of those methods, is a commercial repetitive-sequence-based PCR (rep-PCR) typing system that amplifies strain-specific noncoding repetitive sequences.…”

Clinical and economic outcomes in patients with community‐acquired Staphylococcus aureus pneumonia

“…All S. aureus isolates were entered into a database using Gel Doc 2000 (BioRad) gel documentation system, and PFGE patterns were analyzed using BioNumerics Version 3.5, and grouped into Pulse-field types using DICE coefficients and 80% relatedness. 17 Initial antibiotic therapy was defined to consist of all antibiotics received within the first 48 hours in the hospital, regardless of sequence. Appropriateness of initial antibiotic therapy was ascertained based on susceptibility of the organism to the initial regimen received.…”

Application of RAPD-PCR for Determining the Clonality of Methicillin Resistant Staphylococcus aureus Isolated from Different Hospitals

“…Therefore, the analysis of the spread of these strains has become a great concern throughout the world (Cookson et al 2011). Phenotypic and genotypic methods have been used to determine the polymorphism among these clinical isolates to follow up nosocomial infections (Singh et al 2006). The shortcomings of phenotypical based typing methods have resulted in the improvement of genotypic typing methods based on DNA sequences.…”