IS1245 restriction fragment length polymorphism typing of Mycobacterium avium from patients admitted to a reference hospital in Campinas, Brazil

Mycobacterium avium is an important pathogen among immunodeficient patients, especially patients with AIDS. The natural history of this disease is unclear. Several environmental sources have been implicated as the origin of this infection. Polyclonal infection with this species is observed, challenging the understanding of its pathogenesis and treatment. In the present study 45 M. avium strains were recovered from 39 patients admitted to a reference hospital between 1996 and 1998. Species identification was performed using a species-specific nucleic acid hybridization test (AccuProbe®) from Gen-Probe®. Strains were genotyped using IS1245 restriction fragment length polymorphism typing. Blood was the main source of the organism. In one patient with disseminated disease, M. avium could be recovered more than once from potentially sterile sites. Strains isolated from this patient had different genotypes, indicating that the infection was polyclonal. Four patient clones were characterized in this population, the largest clone being detected in eight patients. This finding points to a common-source transmission of the organism

Detection of mixed infections with Mycobacterium lentiflavum and Mycobacterium avium by molecular genotyping methods

Three mycobacterial isolates, one from the blood of an HIV-infected patient and two consecutive isolates from a woman with unknown HIV status, had been identified as belonging to the Mycobacterium avium complex by conventional procedures. in both patients, using genetic analysis procedures such as PCR-restriction enzyme analysis (PRA) of the hsp65 gene, a commercially available reverse hybridization-based assay (INNO-LiPA MYCOBACTERIA) and/or sequencing analysis of the 16S-23S internal transcribed spacer (ITS), the presence of Mycobacterium lentiflavum was also demonstrated. At the time of detection, both cases were also infected with M. avium, suggesting an underestimation of infection with M. lentiflavum and co-infection with different Mycobacterium species.Fiocruz MS, Inst Oswaldo Cruz, Dept Mycobacterioses, Rio de Janeiro, BrazilFiocruz MS, Inst Oswaldo Cruz, Dept Trop Med, Rio de Janeiro, BrazilUFRJ, Univ Hosp Clementino Fraga Filho, Rio de Janeiro, BrazilUFRJ, Inst Microbiol, Rio de Janeiro, BrazilInnogenet NV, B-9052 Ghent, BelgiumAdolfo Lutz Inst, São Paulo, BrazilEscola Paulista Med, Dept Microbiol Immunol & Parasitol, São Paulo, BrazilEscola Paulista Med, Dept Microbiol Immunol & Parasitol, São Paulo, BrazilWeb of Scienc

Identification of Mycobacteria by Thin Layer Chromatographic Analysis of Mycolic Acids and Conventional Biochemical Method: Four Years of Experience

Mycolic acids analysis by thin-layer chromatography (TLC) has been employed by several laboratories worldwide as a method for fast identification of mycobacteria. This method was introduced in Brazil by our laboratory in 1992 as a routine identification technique. Up to the present, 861 strains isolated were identified by mycolic acids TLC and by standard biochemical tests; 61% out of these strains came as clinical samples, 4% isolated from frogs and 35% as environmental samples. Mycobacterium tuberculosis strains identified by classical methods were confirmed by their mycolic acids contents (I, III and IV). The method allowed earlier differentiation of M. avium complex - MAC (mycolic acids I, IV and VI) from M. simiae (acids I, II and IV), both with similar biochemical properties. The method also permitted to distinguish M. fortuitum (acids I and V) from M. chelonae (acids I and II) , and to detect mixed mycobacterial infections cases as M. tuberculosis with MAC and M. fortuitum with MAC. Concluding, four years experience shows that mycolic acids TLC is an easy, reliable, fast and inexpensive method, an important tool to put together conventional mycobacteria identification methods

Positividade sorológica antiPGL-I em contatos domiciliares e peridomiciliares de hanseníase em área urbana Seropositivity with anti-PGL-I of household and neighbours contacts of leprosy patients in an urban area

FUNDAMENTOS: Pesquisas atuais buscam avaliar a prevalência de pessoas infectadas pelo M. leprae, bem como o valor preditivo dos testes utilizados, em meio aos quais está a sorologia, que detecta anticorpos contra um antígeno específico da parede do Mycobacterium leprae, o glicolipídio fenólico (PGL-I). OBJETIVOS: Conhecer a taxa de infecção em contatos intra e peridomiciliares, e a relação de soropositividade com sexo, idade e grupo multibacilar/paucibacilar. MATERIAIS E MÉTODOS: Inquérito soroepidemiológico em contatos domiciliares e peridomiciliares dos casos notificados como hanseníase entre 1998 e 2002, no segundo distrito do Município de Duque de Caxias, RJ, utilizando o teste sorológico rápido de fluxo lateral ou ML Flow. RESULTADOS: Em 390 domicílios de casos de hanseníase foram identificados 2.130 contatos, e submetidos à sorologia 1.866 (12,4% de perda). A soropositividade foi de 15,7% (292/1.866), sendo 15,8% no domicílio e 15,6% no peridomicílio. Também não houve diferença na relação entre soropositividade e sexo e em maiores e menores de 15 anos. Observou-se diferença significativa na soropositividade de contatos de casos de hanseníase MB (67,5%), duas vezes maior do que a dos casos de PB (32,5%). DISCUSSÃO / CONCLUSÃO: Nas condições de moradia da periferia urbana de área endêmica devem ser submetidos igualmente à vigilância epidemiológica os contatos domiciliares e peridomiciliares.<br>BACKGROUND: Actually many studies have been made to evaluate the predictive value of tests that identify patients infected by Mycobacterium leprae. Among then, the serology that determinates the presence o M. leprae specific antibody. OBJECTIVES: To know the infections tax among households and direct neighbours contacts, establish soropositivity relationship according to sex, household/ neighbour, age and classification of leprosy of the index case (paucibacillary x multibacillary). PATIENTS AND METHODS: seroepidemiological study covering all the household and neighbours of leprosy patients diagnosticated from 1998 to 2002, in the second district of Duque de Caxias, Rio de Janeiro, using fast ML-Flow. RESULTS: A total of 2.130 contacts were identified in 390 domiciles of leprosy patients. Of the 2130 contacts, 1866 were submmited to serology (12.4% lost). Seroprevalence was 15,7%(292/1866); 15.8% household and 15.6% neighbour. The relationship of seropositivity with sex and age (>15 >15 years old) did not shown any statistic difference. But it was seen among contacts of MB index cases ( 67,5%) 2 times higher than contacts of PB cases (32,5%). DISCUSSION / CONCLUSION: In highly endemic areas for leprosy, situated at peripheral metropoliten cities not only household contacts of the index case, but also people living in the close vicinity were more likely to harbour antibodies against M. leprae. Through measuring the serological status of contacts and using a broader definition for them, higher risk groups can be more specifically identified

Association of leprosy with HLA-DR2 in a Southern Brazilian population

The association between HLA specificities and leprosy was investigated in a Southern Brazilian population. One hundred and twenty-one patients and 147 controls were typed for HLA-A, B, Cw, DR and DQ. Patients were subdivided into the following subgroups, according to clinical, histological and immunological criteria: lepromatous (N = 55), tuberculoid (N = 32), dimorphous (N = 20), and indeterminate (N = 14). The frequencies of HLA specificities were compared between the total group of patients and controls, and between the same controls and each subgroup of patients. After correction of the probabilities, deviations were not significant, except for the DR2 specificity, which presented a frequency of 44.2% in the total group of patients and 56.3% in the subgroup of individuals with the tuberculoid form of the disease, compared to 23.3% in the controls. Stratified analysis showed that the increased DR2 frequency in the total group of patients was due to the subgroups with the tuberculoid and dimorphous forms. The relative risk of tuberculoid leprosy for DR2-positive individuals was 4.2, and the etiologic fraction of DR2 was 0.429. In conclusion, a positive association of the DR2 specificity with the tuberculoid form of leprosy, but not with the lepromatous, dimorphous, or indeterminate forms, was demonstrated in this Southern Brazilian populatio