Toward the identification, characterization and experimental culture ofLacazia loboifrom Atlantic bottlenose dolphin (Tursiops truncatus)

Abstract

Lobomycosis (lacaziosis) is a chronic, granulomatous, fungal infection of the skin and subcutaneous tissues of humans and dolphins. To date, the causative agent, the yeast-like organism Lacazia loboi, has not been grown in the laboratory, and there have been no recent reports describing attempts to culture the organism. As a result, studies on the efficacy of therapeutics and potential environmental reservoirs have not been conducted. Therefore, the objective of the current study was to utilize both classical and novel microbiological methods in order to stimulate growth of Lacazia cells collected from dolphin lesions. This included the experimental inoculation of novel media, cell culture, and the use of artificial skin matrices. Although unsuccessful, the methods and results of this study provide important insight into new approaches that could be utilized in future investigations of this elusive organism.

Cutaneous Granulomas in Dolphins Caused by Novel UncultivatedParacoccidioides brasiliensis

“…Since cutaneous granulomas containing chains of yeast-like cells in 3 dolphin species ( Sotalia guainensis , T. aduncus , and T. truncatus ) were initially reported, the etiologic agent of lacaziosis/lobomycosis was believed to be L. loboi , which causes similar skin granulomas in humans ( 1 – 7 , 19 ). This hypothesis was based on phenotypic characteristics of the pathogen (uniform size yeast-like cells in chains connected by slender isthmuses and resistance to culture) and clinical presentation (keloidal-like granulomas) in humans and dolphins with lacaziosis/lobomycosis ( 1 , 4 , 19 ).…”

“…On the basis of these serologic studies ( 4 , 6 , 21 ), current phylogenetic data for gp43 and Kex gene exons, and ITS DNA sequences, placement of L. loboi from humans in its own genus is questionable. Efforts to culture the organism from dolphins on classical laboratory media successfully used to isolate P. brasiliensis from humans with paracoccidioidomycosis were not successful ( 4 , 7 ). The physiologic basis of the inability to culture the etiologic agent from dolphins with cutaneous granulomas is not known.…”

“…Although several studies indicated that L. loboi from human resists culture ( 4 – 6 ), only 1 well-documented study shows the uncultivated nature of the pathogen causing cutaneous granulomas in dolphins ( 7 ). Thus, the true ecology, epidemiology, and taxonomy of these 2 uncultivated pathogens of humans and dolphins have been controversial ( 4 , 7 ). …”

The Bottlenose Dolphin Epigenetic Aging Tool (BEAT): A Molecular Age Estimation Tool for Small Cetaceans

“…Skin samples from 39 bottlenose dolphins collected from June 2004 through May 2009 by the Sarasota Dolphin Research Program (Sarasota, FL, United States), as part of capturerelease health assessments of the long-term resident Sarasota Bay dolphin community (Wells et al, 2004(Wells et al, , 2005 were used. This community has been studied since 1970, through at least six generations, and at any given time includes up to five concurrent generations within a single maternal lineage, and individuals up to 67 years of age (Irvine and Wells, 1972;Wells, 2014). As of 2015, the community was composed of 157.53 ± 43.05 SE dolphins (Tyson and Wells, 2016).…”

Health and Environmental Risk Assessment Project for bottlenose dolphins Tursiops truncatus from the southeastern USA. I. Infectious diseases

“…The presumed etio logic agent, Lacazia loboi, was described as a yeast-like organism found abundantly within lesions but not able to be cultured in vitro (Taborda et al 1999, Schaefer et al 2016. As a result, the development of diagnostic tools to help elucidate disease pathogenesis and epidemiology was impeded.…”