Granulomatous skin lesions in moray eels caused by a novel Mycobacterium species related to Mycobacterium triplex.

Published

Journal Article

An outbreak of granulomatous dermatitis was investigated in a captive population of moray eels. The affected eels had florid skin nodules concentrated around the head and trunk. Histopathological examination revealed extensive granulomatous inflammation within the dermis and subcutaneous fascial plane between the fat and axial musculature. Acid-fast rods were detected within the smallest lesions, which were presumably the ones that had developed earliest. Eventually, after several months of incubation at room temperature, a very slowly growing acid-fast organism was isolated. Sequencing of the 16S rRNA gene identified it as a Mycobacterium species closely related (0.59% divergence) to M. triplex, an SAV mycobacterium. Intradermal inoculation of healthy green moray eels with this organism reliably reproduced the lesion. Experimentally induced granulomatous dermatitis appeared within 2 weeks of inoculation and slowly but progressively expanded during the 2 months of the experiment. Live organisms were recovered from these lesions at all time points, fulfilling Koch's postulates for this bacterium. In a retrospective study of tissues collected between 1993 and 1999 from five spontaneous disease cases, acid-fast rods were consistently found within lesions, and a nested PCR for the rRNA gene also demonstrated the presence of mycobacteria within affected tissues.

Full Text

Duke Authors

Cited Authors

  • Herbst, LH; Costa, SF; Weiss, LM; Johnson, LK; Bartell, J; Davis, R; Walsh, M; Levi, M

Published Date

  • July 2001

Published In

Volume / Issue

  • 69 / 7

Start / End Page

  • 4639 - 4646

PubMed ID

  • 11402008

Pubmed Central ID

  • 11402008

Electronic International Standard Serial Number (EISSN)

  • 1098-5522

International Standard Serial Number (ISSN)

  • 0019-9567

Digital Object Identifier (DOI)

  • 10.1128/IAI.69.7.4639-4646.2001

Language

  • eng