[Infections caused by environmental mycobacteria in Spain]

[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.

Disease-specific cross-reactivity between mimicking peptides of heat shock protein of Mycobacterium gordonae and dominant epitope of E2 subunit of pyruvate dehydrogenase is common in Spanish but not British patients with primary biliary cirrhosis

Previous studies on Spanish patients with Primary Biliary Cirrhosis (PBC) have shown extensive, disease-specific cross-reactivity between the 65-kDa heat shock protein (hsp65) of Mycobacterium gordonae and pyruvate dehydrogenase complex-E2 (PDC-E2), the major target of anti-mitochondrial antibody (AMA). Studies on a British population were unable to substantiate these findings. Having found that there is an excellent and almost unique match between the PDC-E2 autoepitope and a sequence in mycobacterial hsp65s, we tested the corresponding peptides by ELISA for cross-reactivity using sera from 90 PBC patients, 40 Spanish and 50 British, and 84 pathological controls. Reactivity to the MYCGO hsp65(90-104)/human PDC-E2(212-226)pair was present in 19 (47.5%) Spanish PBC patients and in 2 (4%) of the 50 British. Reactivity was not seen in any of the controls. Simultaneous reactivity to mimics was due to cross-reactivity as confirmed by inhibition studies. Three dimensional modelling predicts mycobacterial hsp65(90-104)to be exposed on the surface of the protein. The affinity of anti-hsp65(90-104)antibody was higher than that of anti-PDC-E2(212-226). Hsp65(90-104)is a target of disease-specific cross-reactivity to PDC-E2(212-226). The geographical confinement of this phenomenon is probably the result of complex genetic, environmental and immunological interaction.