Molecular diagnosis of Pneumocystis pneumonia in dogs.

Abstract

Pneumocystis pneumonia (PCP) is a life-threatening fungal disease that can occur in dogs. The aim of this study was to provide a preliminary genetic characterisation of Pneumocystis carinii f.sp.'canis' (P. canis) in dogs and thereby develop a reliable molecular protocol to definitively diagnose canine PCP. We investigated P. canis in a variety of lung specimens from dogs with confirmed or strongly suspected PCP (Group 1, n = 16), dogs with non-PCP lower respiratory tract problems (Group 2, n = 65) and dogs not suspected of having PCP or other lower respiratory diseases (Group 3, n = 11). Presence of Pneumocystis DNA was determined by nested PCR of the large and small mitochondrial subunit rRNA loci and by a real-time quantitative polymerase chain reaction (qPCR) assay developed using a new set of primers. Molecular results were correlated with the presence of Pneumocystis morphotypes detected in cytological/histological preparations. Pneumocystis DNA was amplified from 13/16 PCP-suspected dogs (Group 1) and from 4/76 dogs of control Groups 2 and 3 (combined). The latter four dogs were thought to have been colonized by P. canis. Comparison of CT values in 'infected' versus 'colonized' dogs was consistent with this notion, with a distinct difference in molecular burden between groups (CT ≤ 26 versus CT range (26 <CT < 35), respectively). Phylogenetic analyses showed that P. canis is specifically 'canine' associated, being separated from other mammalian Pneumocystis species, thereby confirming the accuracy of qPCR amplicon for Pneumocystis in dogs. Using qPCR, Pneumocystis DNA can be detected in specimens from the respiratory tract and a CT value can be interpreted to distinguish infection versus colonization.

• Authors: Patrizia Danesi, Silvia Ravagnan, Lynelle R Johnson, Tommaso Furlanello, Adelaide Milani, Patricia Martin, Susan Boyd, Matthew Best, Bradley Galgut, Peter Irwin, Paul J Canfield, Mark B Krockenberger, Catriona Halliday, Wieland Meyer, Richard Malik
• Journal: Medical mycology (Med Mycol) Vol. 55 Issue 8 Pg. 828-842 (Nov 01 2017) ISSN: 1460-2709 [Electronic] England
• PMID: 28339756 (Publication Type: Journal Article)
• Copyright: © The Author 2017. Published by Oxford University Press on behalf of The International Society for Human and Animal Mycology. All rights reserved. For permissions, please e-mail: [email protected].

Chemical References

• DNA Primers
• DNA, Fungal
• RNA, Mitochondrial
• RNA

Topics

• Animals
• Bronchoalveolar Lavage Fluid (microbiology)
• DNA Primers
• DNA, Fungal (genetics)
• Dog Diseases (diagnosis, microbiology, pathology)
• Dogs
• Lung (microbiology)
• Mycological Typing Techniques (veterinary)
• Phylogeny
• Pneumocystis carinii (classification, genetics)
• Pneumonia, Pneumocystis (diagnosis, pathology, veterinary)
• RNA (genetics)
• RNA, Mitochondrial
• Real-Time Polymerase Chain Reaction
• Sensitivity and Specificity