Emergence of a unique group of necrotizing mycobacterial diseases.

Although most diseases due to pathogenic mycobacteria are caused by Mycobacterium tuberculosis, several other mycobacterial diseases-caused by M. ulcerans (Buruli ulcer), M. marinum, and M. haemophilum-have begun to emerge. We review the emergence of diseases caused by these three pathogens in the United States and around the world in the last decade. We examine the pathophysiologic similarities of the diseases (all three cause necrotizing skin lesions) and common reservoirs of infection (stagnant or slow-flowing water). Examination of the histologic and pathogenic characteristics of these mycobacteria suggests differences in the modes of transmission and pathogenesis, though no singular mechanism for either characteristic has been definitively described for any of these mycobacteria

Cutaneous vasculitis associated with fluoroquinolones

Cutaneous vasculitis is a clinical entity with a broad differential diagnosis, including an adverse drug reaction. It is defined as inflammation of skin blood vessel walls. During a 7-year-period, we observed three patients who developed isolated cutaneous vasculitis during antibiotic therapy of bacterial infection. All were treated with a fluoroquinolone (ciprofloxacin or levofloxacin) combined with rifampin (two cases) or flucloxacillin (three cases), respectively. In all three cases the lesions gradually resolved after treatment with the inciting fluoroquinolone had been stopped. In one patient, leukocytoclastic small-vessel vasculitis was histologically confirmed. Fluoroquinolone-associated cutaneous vasculitis consists of an isolated self-limiting disorder that is part of a systemic vasculitis, or even life-threatening disease. Clinicians should be aware of this serious adverse event because any continuation of treatment may be fatal