Heterogeneity and compartmentalization of Pneumocystis carinii f. sp. hominis genotypes in autopsy lungs.

Jannik Helweg-Larsen,Jens D Lundgren,Bettina Lundgren

doi:10.1128/jcm.39.10.3789-3792.2001

Jannik Helweg-Larsen, Jens D Lundgren + Show 1 more

Open Access

https://doi.org/10.1128/jcm.39.10.3789-3792.2001

Copy DOI

Abstract

The extent and importance of genotype heterogeneity of Pneumocystis carinii f. sp. hominis within lungs have not previously been investigated. Two hundred forty PCR clones obtained from respiratory specimens and lung segments from three patients with fatal P. carinii pneumonia were investigated to detect genetic diversity in the internal transcribed spacer (ITS) region of the nuclear rRNA operon, the mitochondrial large-subunit (mtLSU) rRNA gene, and the dihydropteroate synthase-encoding gene. For two of the three examined patients, a mixture of different mtLSU rRNA and ITS genotypes was observed. Not all genotypes present in the lungs at autopsy were detected in the diagnostic respiratory samples. Compartmentalization of specific ITS and mtLSU rRNA sequence types was observed in different lung segments. In conclusion, the interpretation of genotype data and in particular ITS sequence types in the assessment of epidemiological questions should be cautious since genotyping done on respiratory samples cannot a priori be assumed to represent all genotypes present within the lung.

Highlights

The interpretation of molecular typing results in epidemiological studies of Pneumocystis carinii is complicated by the existence of coinfections
The mitochondrial large-subunit rRNA and internal transcribed spacer (ITS) loci were chosen for analysis since these genes are genes most frequently used for genotype analysis and the dihydropteroate synthase (DHPS) locus, the target of sulfone and sulfonamide drugs, was chosen because of its association with sulfa resistance [9, 16]
Specimens were obtained at diagnosis and postmortem from three patients who died of P. carinii pneumonia (PCP) between 1994 and 1997

Summary

Introduction

The interpretation of molecular typing results in epidemiological studies of Pneumocystis carinii is complicated by the existence of coinfections. For patient AIDS-1, a single mtLSU rRNA sequence type with T at position 85 and C at position 248 was observed in the diagnostic BAL and in all autopsy lung recombinant clones. For the HL patient, four different mtLSU rRNA genotypes were observed in the lungs.

Results

Conclusion