Sporotrichoid cutaneous infection caused by Mycobacterium marinum

High-mortality epizootic Mycobacterium ulcerans ecovar Liflandii in a colony of Zaire Dwarf Clawed Frogs (Hymenochirus boettgeri)

Mycobacterium ulcerans ecovar Liflandii (MuLiflandii) was identified as the causative agent of mycobacteriosis in a research colony of Zaire dwarf clawed frogs (Hymenochirus boettgeri) at the University of Michigan. Clinical presentation included lethargy, generalized septicemia, cutaneous granulomas, coelomic effusion, and acute mortality. Identification of the mycobacterial species was based on molecular, microbiological, and histopathologic characteristics. These findings indicate that MuLiflandii is a primary cause of morbidity and mortality in Zaire dwarf clawed frogs and should be considered in the differential diagnosis of sepsis and coelomic effusion in amphibians. Mycobacterial speciation is important given the variability in pathogenesis within the family Mycobacteriaceae and the implications for both animal and human health as potential zoonoses. The Zaire dwarf clawed frog is a species common in the pet trade, and these findings provide consideration for this pathogen as a potentially important public health concern. This is the first report of MuLiflandii infection in the genus Hymenochirus and illustrates the diagnostic challenges of differentiating among both mycolactone-producing mycobacteria and Mycobacterium marinum. Furthermore, we demonstrate the utility of environmental sampling for this pathogen within the tank system, suggesting this mode of sampling could replace the need for direct frog surveillance.

Upper extremity Mycobacterium marinum infection

Mycobacterium marinum is the cause of opportunistic infections in man. Although its clinical presentation is usually cutaneous, osteoarticular infections are not rare and should be rapidly diagnosed. Orthopaedic surgeons may have to manage a patient with this mycobacterial infection and should be able to make this diagnosis based on information about the patient's history and clinical criteria. Lesions develop from a skin wound, with a single nodule or a bright purplish-red patch with papules; they also may be inflamed or may abscess. Secondary lesions may develop as the disease progresses. Aquatic exposure is the most important factor to look for. We report three cases of this infection with a delayed diagnosis. Response to treatment and an absence of complications are correlated with an early diagnosis.

Sporotrichosis of the upper extremity

This article presents a case of a chronic, nonhealing thumb wound in a patient with diabetes mellitus. A 67-year-old right-hand-dominant man presented with progressive erythema and swelling of the right thumb several months after sustaining a paper cut along the eponychium. The patient had already completed an extensive laboratory evaluation, including bacterial and fungal cultures, as well as a punch biopsy that was inconclusive. In addition, the patient underwent several rounds of empiric antibiotic therapy without resolution of his symptoms. Despite these measures, the patient's thumb wound persisted and new lesions began to appear proximally along the forearm. Excisional biopsy of the lesions was ultimately required to obtain additional tissue for a pathologic analysis. Culture of the specimen on Saboraud dextrose agar revealed a definitive diagnosis of infection with Sporothrix schenkii. A subsequent course of oral antifungal therapy with itraconazole was well tolerated and resulted in disease regression. Early diagnosis of sporotrichosis is essential to prevent complications including septic arthritis, systemic infection, and death. This case illustrates the importance of maintaining a high index of suspicion for atypical infectious agents in patients with poor immune function.

Transmission of Mycobacterium marinum from fish to a very young child

Mycobacterium marinum causes tuberculosis in fish and can cause skin infections in humans who swim in contaminated water or who have direct contact with infected fish. We report the case study of an 18-month-old girl with M. marinum abscesses, who acquired the infection through indirect contact with a contaminated bucket. Appropriate cleaning of aquarium equipment is very important, especially with young children in the household.

[Mycobacterium marinum infection. Case report and review of the literature]

Atypical mycobacterial infections are increasingly important in immunosuppressed patients as well as in healthy hosts. The atypical mycobacterium that most commonly affects the skin is Mycobacterium marinum. The infection should be suspected upon the presence of ulcers, nodules or chronic plaques and a history of contact with fresh or salt water. Optimal therapy is yet to be established. We report a case of Mycobacterium marinum infection in a patient receiving immunosuppressive therapy that responded favourably to treatment with doxicycline. We review the different antibiotic regimens prescribed in the past years for the treatment of Mycobacterium marinum infection.

[Pediatric infections caused by nontuberculous mycobacteria]

During the last few years, nontuberculous mycobacteria (NTM) have been isolated with increasing frequency in our environment. However, there are only a few reports of pediatric NTM infections in Spain (13 articles since 1990). This article presents an update of the epidemiology, diagnostic methods, and treatment of these infections in children. The most frequent clinical syndromes caused by NTM include lymphadenitis, pulmonary and disseminated infections in immunocompromised children. NTM cervical adenitis usually causes chronic infection associated with sinus tract formation and scarring. The treatment of choice is surgical excision of the involved node. Incision and drainage of the enlarged node should be avoided because it can lead to chronic drainage or sinus tract formation. Medical treatment with azithromycin or clarithromycin associated with rifabutin, ethambutol or ciprofloxacin should be reserved for cases in which the family refuses surgery, a recurrence occurs or complete excision is impossible. Pulmonary disease caused by NTM is relatively rare in immunocompetent children, but is increasingly reported in children with cystic fibrosis. In these patients, the clinical significance of the presence of NTM in the sputum is unclear. The persistence of positive cultures, especially if bacilloscopy is positive and the patient shows clinical evidence of pulmonary disease exacerbation, is an indication to start treatment. Disseminated infection caused by NTM can appear in patients with severe immunodepression, especially in HIV-infected children with CD4 cell counts of less than 100 cells/mm3. Early antibiotic therapy with at least three drugs including a macrolide, and immune recovery with aggressive antiretroviral therapy are the keys to improving quality of life and survival in these patients.