Identification of Mycobacterium marinum in sea-urchin granulomas.
BACKGROUND
Sea-urchin granuloma is a chronic granulomatous reaction arising after injury with sea-urchin spines. Classified as an allergic foreign-body type of granuloma, it is believed to be a delayed-type reaction to an as yet unidentified antigen. In a clinicopathological study, 50 biopsy specimens from 35 patients diagnosed as having sea-urchin granuloma caused by Paracentrotus lividus, we found different inflammatory patterns that in some cases suggested a mycobacterial infection.


OBJECTIVE
To investigate and identify mycobacterial DNA in formalin-fixed and paraffin-embedded skin biopsy specimens diagnosed as sea-urchin granulomas.


METHODS
A search combining polymerase chain reaction amplification using Mycobacterium genus-specific primers, and subsequent restriction enzyme analysis enabling identification to the species level, was performed in 41 samples.


RESULTS
Amplification of a 924-bp DNA fragment encoding mycobacterial 16S rRNA gene was positive in eight biopsy specimens from seven patients (21%). M. marinum-specific restriction patterns were identified in three samples.


CONCLUSIONS
Although further controlled studies are necessary, from these data it would appear that mycobacteria may play a pathogenic role in some cases of sea-urchin granuloma.
De la Torre
C
C
Service of Dermatology, Complejo Hospitalario de Pontevedra, C/Loureiro Crespo s/n, 36001 Pontevedra, Spain. ctorre@arrakis.es
Vega
A
A
Carracedo
A
A
Toribio
J
J
D000293:Adolescent; D000328:Adult; D000818:Animals; D004269:DNA, Bacterial / Q000032:analysis; D005260:Female; D015745:Granuloma, Foreign-Body / Q000209:etiology / Q000382:microbiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D019910:Mycobacterium marinum / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction; D012617:Sea Urchins; D012867:Skin / Q000293:injuries
D004269:DNA, Bacterial