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Genotypic variation in Pneumocystis jirovecii isolates in Britain

R F Miller1, A R Lindley, A Copas

  • 1Centre for Sexual Health and HIV Research, Department of Primary Care and Population Sciences, Royal Free and University College Medical School, University College London, Mortimer Market Centre, London WC1E 6AU, UK. rmiller@gum.ucl.ac.uk

Thorax
|August 3, 2005
PubMed
Abstract

Insights

Molecular epidemiology of Pneumocystis jirovecii in Britain reveals genotype 1 is most common. Specific genotypes cluster by patient residence, suggesting airborne transmission, but don't correlate with Pneumocystis pneumonia severity.

Area of Science:

  • Medical Mycology
  • Molecular Epidemiology
  • Infectious Diseases

Background:

  • Pneumocystis jirovecii causes Pneumocystis pneumonia (PCP) in immunosuppressed individuals.
  • Asymptomatic colonization by P. jirovecii can occur in patients with mild immunosuppression or chronic lung conditions.
  • This study investigated the molecular epidemiology of P. jirovecii in Britain over 12.5 years.

Purpose of the Study:

  • To describe the molecular epidemiology of P. jirovecii in Britain.
  • To investigate potential transmission routes and virulence factors of P. jirovecii genotypes.

Main Methods:

  • Collected 161 P. jirovecii samples from PCP patients, colonized individuals, and air spora (1989-2001).
  • Performed genotyping using the mitochondrial large subunit rRNA (mt LSU rRNA) gene.
  • Analyzed genotype distribution and association with patient residence and PCP severity.

Main Results:

  • Genotype 1 was the most frequent (38%), followed by genotypes 2 (26.6%), 3 (20.3%), and 4 (5%).
  • Mixed infections were found in 10% of samples.
  • Genotype distribution showed clustering by patient postcode, suggesting airborne transmission, but no association with PCP severity (arterial oxygen tension).

Conclusions:

  • Clustering of P. jirovecii genotypes with patient residence supports airborne, person-to-person transmission.
  • The mt LSU rRNA locus does not appear to be involved in P. jirovecii virulence.
  • Understanding P. jirovecii epidemiology is crucial for managing PCP in vulnerable populations.

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