Molecular study of archival fungal strains isolated from cases of lacaziosis (Jorge Lobo's disease)

Abstract

Lacazia loboi, the aetiological agent of lacaziosis (Jorge Lobo's disease), is an uncultivated anomalous fungal microbe closely related to Paracoccidioides brasiliensis, both restricted Latin American Pathogens. Early reports suggesting that L. loboi had been isolated in pure culture from cases of lacaziosis, only added more confusion to the already confusing aetiology of this disease. These strains were later identified as unusual contaminants and some of them as P. brasiliensis. Recent phylogenetic analysis grouped L. loboi as the sister taxon to P. brasiliensis, thus it was postulated that the original P. brasiliensis strains recovered from cases of lacaziosis, could be the aetiological agent of the disease. Using molecular methodologies, we investigated the archival P. brasiliensis isolate No. 525 from a case of lacaziosis, as well as other archival isolates, identified earlier as common contaminants, all recovered from similar cases of the disease. Phylogenetic analysis, using the 18S small subunit rDNA sequences of these isolates showed that strain No. 525 was a typical P. brasiliensis isolate and the other studied strains were indeed contaminants. This study unequivocally indicates that the aetiological agent of lacaziosis is yet to be cultured.

Lobomycosis: an emerging disease in humans and delphinidae

“…have majorly contributed to the clarification of the taxonomic enigma of this agent, placing it in the group of the onygenales dimorphic fungi 23 after amplifying the 18SSU rDNA and 600 bp of the chitin synthetase gene, also suggesting its close phylogenetic relationship with P. brasiliensis , (such as had been previously only presumed on the basis of the morphological and antigenic similarities of both agents), and thereby providing another classification distinct of Paracoccidiodes loboi. 23,24 Since its original description and to date, cases clinically and histologically consistent with infection by Lacazia loboi have been reported in the literature under various descriptive terms including Lobomycosis, Lacaziosis, Jorge Lobo’s disease and Lobo’s disease.…”

Skin Infections

“…644,654,655 The organism contains constitutive melanin in its cell wall, which seems to be associated with spicules (Splendore-Hoeppli phenomenon). loboi has never been cultivated in vitro, but it has been successfully transmitted to mice, tortoises, and armadillos under experimental conditions.…”

The taxonomy of two uncultivated fungal mammalian pathogens is revealed through phylogeny and population genetic analyses

“…Due to its uncultivated nature, placement of this unusual pathogen within a particular taxon was always contentious 2 , 3 , 7 , 8 . Therefore, the pathogen as well as the disease were known under a long list of binomials and disease names including Jorge lobos’ disease, lobomycosis and more recently lacaziosis 2 , 3 , 9 . Based on phenotypic features in the infected tissues, early investigators believed the pathogen was related to the genus Paracoccidioides and thus, at one point, it was named P. loboi 10 , 11 .…”

“…However, the proposal was challenged by many due to the pathogens’ intractability to culture and to the fact that it is restricted to the subcutaneous tissues, both features contrasting to that in Paracoccidioides species 2 , 8 . After a long list of unsuccessful names 2 , 9 – 12 , based on taxonomic nomenclatural issues, the binomial Lacazia loboi was introduced 8 .…”

“…Morphological and molecular data analyzed, other than P. cetii in this study, had been previously published 8 , 9 , 12 – 17 , 23 , 24 , 52 . The DNA sequences and final assembly data in the manuscript have been deposited in the NCBI BioProject database under accession code PRJNA714057.…”