Mycobacterium bolletii/Mycobacterium massiliense furunculosis associated with pedicure footbaths: a report of 3 cases.

BACKGROUND Mycobacterium bolletii and Mycobacterium massiliense are recently described species of nontuberculous mycobacteria. Footbaths preceding pedicures at nail salons have been implicated as reservoirs of infection with nontuberculous mycobacteria. To our knowledge, this case series represents the first documented outbreak of M bolletii/M massiliense furunculosis, identified by heat-shock protein 65 gene, hsp65, sequencing, occurring in immunocompetent patrons of a North Carolina nail salon. OBSERVATIONS We describe 3 cases of lower extremity furunculosis caused by M bolletii/M massiliense associated with pedicure footbaths from the same North Carolina nail salon. Lesions developed within 1 month of the salon visit and were characterized by erythematous, indurated papules and plaques. Histologic examination revealed suppurative granulomatous dermatitis. Mycobacterium bolletii/M massiliense was identified by sequencing the 16S ribosomal RNA (rRNA) and hsp65 genes. All 3 patients responded to different combinations of clarithromycin, doxycycline hydrochloride, azithromycin, and moxifloxacin hydrochloride for complete lesion resolution. CONCLUSIONS Clinicians should elicit a history of pedicure footbaths and maintain a high level of suspicion when faced with skin lesions of the lower extremities that are culture negative or are refractory to conventional antibiotic therapy. Accurate identification and discrimination of M massiliense and M bolletii is difficult and requires sequencing of multiple gene targets beyond their identical 16S rRNA sequences.