In the setting of nosocomial aspergillois and evidence of continuing infection in a hospital population, the US Centers for Disease Control and Prevention (CDC) recommends an environmental assessment to determine and eliminate the source of infection. In such hospital associated outbreak investigations, strain typing methods can indicate the source and/or route of infection; once the source is identified, corrective measures can be undertaken to eliminate the implicated source to effectively contain the infection. Over the past decade, an increasing number of molecular methods have been described for A. fumigatus strain typing including polymorphic microsatellite markers, Afut1 fingerprinting and single locus sequence typing (CSP typing) methods. In spite of the availability of a plethora of sub-typing methods, only a few of them have been validated for use in an outbreak setting and at present there is no consensus typing method. In general, typing methods should generate isolate-specific molecular fingerprints for assessment of genetic relatedness amongst epidemiologically related isolates. It is imperative that such typing data should be considered within the time frame of the outbreak with focus on identifying sources of outbreak. Important considerations for a choosing an appropriate typing method should include: typeability, discriminatory power, reproducibility, ease of use and interpretation of data, cost effectiveness (time and money) and portability of data. This presentation would address the tenets of subtyping methods for outbreak investigation, available Aspergillus strain typing methods and illustrate from some recent outbreak investigations.
Full conference title:
4th Advances Against Aspergillosis
- AAA 4th (2010)