Establishment of a quantitative real-time PCR for the detection of Pneumocystis carinii f. sp. suis in bronchoalveolar lavage samples from pigs

Abstract

Abstract. Respiratory diseases in pigs are mostly polymicrobial, and the involved pathogens can vary from farm to farm. The impact of Pneumocystis carinii (P. c.) f. sp. suis on respiratory disorders has not been comprehensively appraised because tests were limited to lung tissue samples and, for this reason, it was not possible to detect the fungus in living animals. In the present study, bronchoalveolar lavage fluid (BALF) from 12 pigs and oral fluid samples from 9 pigs were tested for the presence of Pneumocystis by quantitative real-time PCR. The results from these 2 clinical specimens were compared with Pneumocystis quantities in lung tissue samples. Pneumocystis quantities in BALF correlated significantly to those in lung tissue. BALF has proved to be an adequate specimen for detection of various respiratory pathogens in pigs, and the collection procedure directly on farms is also well established. In contrast to the BALF results, all oral fluid samples were negative. Thus, specimens from the lower respiratory tract should generally be preferred for the detection of Pneumocystis. Additionally, under farm conditions, oral fluid is mainly collected in the form of collective samples per pen. In the present study, oral swab sampling of individual pigs was intended but failed in 3 of 12 pigs because they did not salivate sufficiently. As a conclusion, only BALF can be recommended as a useful tool for Pneumocystis herd monitoring in vivo.

Diagnosis of pneumocystis pneumonia in a 2‐year‐old King Charles Cavalier Spaniel using the polymerase chain reaction

“…Antemortem diagnosis can be performed via lung biopsies; however, these are invasive and may be risky in a compromised respiratory patient with diseased lungs. This report demonstrates the utility of PCR testing on airway samples collected via BAL and complements the work performed in pigs reported earlier . PCR on BAL fluid represents a relatively noninvasive method by which to determine a definitive antemortem diagnosis.…”

“…This report demonstrates the utility of PCR testing on airway samples collected via BAL and complements the work performed in pigs reported earlier. 10 PCR on BAL fluid represents a relatively noninvasive method by which to determine a definitive antemortem diagnosis. Although serologic testing is possible, it is not a reliable method to diagnose Pneumocystis due to possible immunodeficiency.…”

Molecular detection ofPneumocystisin the lungs of cats

“…21,36,39,40 Rare spontaneous cases of Pneumocystis pneumonia (PCP) in pigs (adult and piglets) are mostly linked with immunosuppression from adverse environmental conditions (stressful farming conditions, overcrowding, high ambient ammonia concentrations, perhaps complicated by suboptimal nutrition) and/or genetic predispositions. [41][42][43] In pigs, Pneumocystis is generally eliminated from the lungs or constrained to small quiescent foci unless such immunosuppressive conditions are present. 43,44 The concurrent presence of other opportunistic pathogens such as Bordetella bronchiseptica in the airways and demodicosis in the skin of dogs, 40 and porcine circovirus type 2 (PCV-2) and Mycoplasma hyopneumoniae in pigs 29 with Pneumocystis has been well established.…”

“…[41][42][43] In pigs, Pneumocystis is generally eliminated from the lungs or constrained to small quiescent foci unless such immunosuppressive conditions are present. 43,44 The concurrent presence of other opportunistic pathogens such as Bordetella bronchiseptica in the airways and demodicosis in the skin of dogs, 40 and porcine circovirus type 2 (PCV-2) and Mycoplasma hyopneumoniae in pigs 29 with Pneumocystis has been well established. The same is true also for macrobats, where, for example, Histoplasma capsulatum coexists with Pneumocystis spp.…”

Pneumocystosis in dogs: meta-analysis of 43 published cases including clinical signs, diagnostic procedures, and treatment

“…The reliability of results is limited, even in the hands of experienced laboratory personnel. PCR testing of BALF or lung aspirates has proved useful in dogs and pigs 8,42 and should probably be attempted more often, as the requirement to perform open lung biopsies to secure a diagnosis is unnecessarily invasive.…”