Phylogenetic analysis of Pneumocystis from pig lungs obtained from slaughterhouses in southern and midwestern regions of Brazil / Análise filogenética de Pneumocystis obtidos de pulmões de suínos provenientes de abatedouros da região sul e centro oeste do Brasil

The Pneumocystis genus is comprised of pathogens dwelling in the lungs of terrestrial, aerial, and aquatic mammals. Occasionally they induce severe pneumonitis, particularly in hosts with severe impairment of the immune system and progressively may fill pulmonary alveolar cavities causing respiratory failure. Molecular genetic studies revealed that Pneumocystis gene sequences present a marked divergence with the host species concerned. In the present study, the genetic diversity of Pneumocystis obtained from lungs of swines was examined by analyzing mitochondrial large subunit (mtLSU) and small subunit (mtSSU) rRNA sequences. The samples were obtained from two slaughterhouses located in two Brazilian states. Phylogenetic analysis demonstrated that genetic groupings within Pneumocystis organisms were in accordance with those of the corresponding hosts and that two clusters were formed. In conclusion, these data show that there are genetically distinct porcine Pneumocystis genotypes with at least two separate clusters in Brazil.

O gênero Pneumocystis compreende patógenos que residem em pulmões de animais terrestres, aéreos e aquáticos. Pode ocasionar uma grave pneumonia, particularmente em hospedeiros com o sistema imunológico seriamente comprometido, o que ocorre por meio de uma progressiva disseminação nas cavidades alveolares, causando insuficiência respiratória. Estudos genéticos, baseados em métodos moleculares, revelaram que as sequências dos genes de Pneumocystis apresentam marcante divergência de acordo com a espécie de hospedeiro. Neste estudo, a diversidade genética das amostras obtidas a partir de pulmões de suínos, provenientes de dois abatedouros localizados em dois estados brasileiros, foi examinada por análise das sequencias dos nucleotídeos dos produtos de PCR dos genes mtLSU e mtSSU do rRNA do Pneumocystis. O resultado confirma a tendência registrada em pesquisas com amostras de outros animais e permite concluir que existem, pelo menos, dois grupos filogenéticos distintos de Pneumocystis de suínos no Brasil.

Pneumocystis diversity as a phylogeographic tool

Parasites are increasingly used to complement the evolutionary and ecological adaptation history of their hosts. Pneumocystis pathogenic fungi, which are transmitted from host-to-host via an airborne route, have been shown to constitute genuine host markers of evolution. These parasites can also provide valuable information about their host ecology. Here, we suggest that parasites can be used as phylogeographic markers to understand the geographical distribution of intra-specific host genetic variants. To test our hypothesis, we characterised Pneumocystis isolates from wild bats living in different areas. Bats comprise a wide variety of species; some of them are able to migrate. Thus, bat chorology and migration behaviour can be approached using Pneumocystis as phylogeographic markers. In the present work, we find that the genetic polymorphisms of bat-derived Pneumocystis are structured by host chorology. Therefore, Pneumocystis intra-specific genetic diversity may constitute a useful and relevant phylogeographic tool.