Detection ofPneumocystisinfections by in situ hybridization in lung samples of Austrian pigs with interstitial pneumonia

Abstract

Pneumocystis carinii f. sp. suis is a fungus multiplying in the respiratory tract of pigs which occasionally is associated with interstitial pneumonia. Identification of Pneumocystis in tissue samples is considered difficult and there are only scarce data on its occurrence in European pigs. This investigation presents an in situ hybridization (ISH) procedure for identification of Pneumocystis spp. in paraffin wax embedded tissue samples and its application for labeling the agent in lung samples of pigs with interstitial pneumonia. Thirty-two out of 100 lung samples from pigs on Austrian farms were identified as positive, five of them with multiple, 12 with moderate and 15 with few organisms but Grocott’s methenamine silver staining demonstrated that only 20 cases were unequivocally positive for Pneumocystis carinii. In addition to interstitial pneumonia Pneumocystis-positive pigs were more frequently affected with granulomatous pneumonia than Pneumocystis-negative pigs. Frequently concurrent infections with different viral or bacterial lung pathogens were noted but there was no positive correlation between Pneumocystis- and PCV-2-infections. With other infections, no clear-cut differences between Pneumocystis-positive and Pneumocystis-negative animals were found. This study shows that Pneumocystis infections occur frequently in Austrian pigs with interstitial pneumonia. It remains to be shown which are the factors triggering severe multiplication and whether infection with Pneumocystis alone is able to induce lung disease in pigs.

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

“…1 The oligonucleotide probe sequence was designed within the 18S ribosomal (r)RNA gene (5′-GGAACCCGAAGACTTT GATTTCTCATAAGATGCCGAGCGA-3′). The semiquantitative analysis was assessed using the score +++ for multiple, ++ for moderate, and + for few organisms (Fig.…”

“…suis is an opportunistic fungus that is mainly associated with milder lung lesions, such as interstitial pneumonia. 1 The fungus is found in pigs with a relatively high prevalence (32%), and coinfections with other respiratory pathogens are frequently observed. 1 Respiratory diseases in pigs have been described to be polymicrobial and multifactorial, and the involved pathogens can vary markedly from farm to farm.…”

Molecular detection ofPneumocystisin the lungs of cats

“…Thus, trophozoites are difficult or impossible to visualize in histological sections from modestly colonized lung, unless in situ hybridization (ISH) is used, as has been recently described for pig lungs. 29 In histology preparations of Pneumocystis PCR-positive cats, we also did not detect lung damage referable to Pneumocystis infection. The same observations have been made in human autopsy studies, in which Pneumocystis jirovecii can be detected without observation of obvious pulmonary lesions in immunocompetent infants.…”

Age-related presence of selected viral and bacterial pathogens in paraffin-embedded lung samples of dogs with pneumonia

“…is an opportunistic fungal pathogen of many different animal species as well as humans (Stringer, 1996), which can induce dyspnoea and pneumonia in dogs, especially in immunosuppressed individuals (Lobetti, 2012). In order to determine whether this agent was previously overlooked in the examined pneumonia cases a previously described ISH procedure was applied (Binanti et al, 2014). Pneumocystis spp.…”

“…The procedures followed previously described protocols (CAV-2: Benetka et al, 2006; Pneumocystis spp. : Binanti et al, 2014). The probe sequences are listed in Table 2.…”