[Frontiers in Bioscience 7, e354-361, October 1, 2002]

MOLECULAR EPIDEMIOLOGY OF PSEUDOMONAS AERUGINOSA

David P. Speert

Research Centre, Vancouver, B.C., V5Z 4H4, Canada

TABLE OF CONTENTS

1. Abstract
2. Introduction
3. Infections caused by Pseudomonas aeruginosa
3.1. Cystic fibrosis
3.2. Sepsis in compromised hosts
3.3. Burn wound infections 3.4. Superficial infections
4. Phenotypic typing methods
4.1. Lipopolysaccharide serotyping
4.2. Other methods
5. Molecular typing methods
5.1. Restriction fragment length polymorphism
5.2. Pulsed field gel electrophoresis
5.3. PCR-based methods
5.3.1. Random amplified Polymorphic DNA analysis
5.3.2. Repetitive Extrapalindromic PCR
5.4. Multilocus sequence typing
6. Epidemiology of Pseudomonas aeruginosa in patients with cystic fibrosis
6.1. Evidence for patient to patient spread
6.2. Evidence against patient to patient spread
6.3. Rational infection control practices based upon local epidemiology
7. Epidemiology of P. aeruginosa in other medical conditions
7.1. Burns
7.2. Ventilator-associated pneumonia
7.3. Cancer and neutropenia
8. Conclusions
9. Acknowledgments
10. References

1. ABSTRACT

Pseudomonas aeruginosa is a serious opportunistic pathogen in certain compromised hosts, such as those with cystic fibrosis, thermal burns and cancer. It also causes less severe noninvasive disease, such as otitis externa and hot tub folliculitis, in normal hosts. P. aeruginosa is phenotypically very unstable, particularly in patients with chronic infection. Phenotypic typing techniques are useful for understanding the epidemiology of acute infections, but they are limited by their discriminatory power and by their inability to group isolates that are phenotypically unrelated but genetically homologous. Molecular typing techniques, developed over the past decade, are highly discriminatory and are useful for typing strains from patients with chronic infection where the bacterial phenotype is unstable; this is particularly true in cystic fibrosis, where patients often are infected with the same strain for several decades, but the bacteria undergo phenotypic alteration. Molecular typing techniques, which have proven useful in typing P. aeruginosa for epidemiological purposes, include pulsed field gel electrophoresis, restriction fragment length polymorphic DNA analysis, random amplified polymorphic DNA analysis, repetitive extrapalindromic PCR analysis, and multilocus sequence typing. These methods are generally only available in specialized laboratories, but they should be used when data from phenotypic typing analysis are ambiguous or when phenotypic methods are unreliable, such as in cystic fibrosis.