Enoyl-coenzyme A hydratase and antigen 85B of Mycobacterium habana are specifically recognized by antibodies in sera from leprosy patients.

Leprosy is an infectious disease caused by Mycobacterium leprae, which is a noncultivable bacterium. One of the principal goals of leprosy research is to develop serological tests that will allow identification and early treatment of leprosy patients. M. habana is a cultivable nonpathogenic mycobacterium and candidate vaccine for leprosy, and several antigens that cross-react between M. leprae and M. habana have been discovered. The aim of the present study was to extend the identification of cross-reactive antigens by identifying M. habana proteins that reacted by immunoblotting with antibodies in serum samples from leprosy patients but not with antibodies in sera from tuberculosis (TB) patients or healthy donors (HDs). A 28-kDa antigen that specifically reacted with sera from leprosy patients was identified. To further characterize this antigen, protein spots were aligned in two-dimensional polyacrylamide gels and Western blots. Spots cut out from the gels were then analyzed by mass spectrometry. Two proteins were identified: enoyl-coenzyme A hydratase (lipid metabolism; ML2498) and antigen 85B (Ag85B; mycolyltransferase; ML2028). These proteins represent promising candidates for the design of a reliable tool for the serodiagnosis of lepromatous leprosy, which is the most frequent form in Mexico.

Isolation of Hanseniaspora uvarum (Kloeckera apiculata) in humans.

Isolation of Hanseniaspora uvarum, a yeast of the ascomycetes group, whose anamorph corresponds to Kloeckera apiculata, obtained from stool and two ungual specimens from three patients, is reported. This yeast has been found in soil, water, various fruits, bivalve molluscs, crabs, prawns and fruit flies; in Spain, it has been described in the fermentation processes of some wines. In our region, it has also been found in the intestine of mackerel (Scomber scombrus). Its finding in humans constitutes a clinical rarity.

Analysis of the immunological humoral response to Mycobacterium tuberculosis glycolipid antigens (DAT, PGLTb1) for diagnosis of tuberculosis in HIV-seropositive and -seronegative patients.

Using an enzyme immunoassay (EIA) test, the concentrations of IgG antibodies against 2,3 diacyl trehalose (DAT) and phenolic glycolipid Tb1 (PGLTb1) were measured in the sera of 153 patients with active tuberculosis, 50 of whom were coinfected with HIV, and in the sera of 152 healthy blood donors, 149 asymptomatic HIV-seropositive patients, 12 HIV-seronegative patients with conditions simulating tuberculosis, 23 HIV-seropositive patients with disseminated infection caused by mycobacteria other than tuberculosis and 24 HIV-seropositive patients with pulmonary disease from whom mycobacteria was not isolated in culture. A slightly lower percentage (74%) of the HIV-seropositive than the HIV-seronegative (77%) tuberculosis patients were positive for anti-DAT and anti-PGLTb1 IgG antibodies, with a specificity ranging from 91 to 95%. There was no significant difference between EIA sensitivity in smear-positive and smear-negative patients with pulmonary tuberculosis for all HIV immune statuses and sites of disease (pulmonary vs. extrapulmonary). In HIV-seropositive patients, however, sensitivity was always lower for disseminated tuberculosis than for localized tuberculosis. Combining data for both the smear test and the EIA maximized sensitivity. The main value of the EIA test could be to provide early complementary information by antibody detection in patients with tuberculosis, particularly those with a negative smear test.

BCG vaccination protects against leprosy in Venezuela: a case-control study.

A total of 64,570 household and other close contacts of about 2000 leprosy cases were screened for eligibility for entry into a trial of a new leprosy vaccine. The screening procedure included a clinical examination for leprosy and for the presence of BCG and lepromin scars. Ninety-five new cases of leprosy were identified, and the prevalence of BCG and lepromin scars among them was compared with similar data from matched controls selected from among those with no evidence of leprosy. The difference in the prevalence of BCG scars in the two groups was used to estimate the protection against leprosy conferred by BCG vaccination. One or more BCG scars was associated with a protective efficacy of 56% (95% confidence limits 27% to 74%). There was a trend of increasing protection with four or more BCG scars, but this was not statistically significant. There was no evidence that the efficacy of BCG varied with age or according to whether or not the contact lived in the same household as a case. The protective effect was significantly higher among males, and was significantly greater for multibacillary than for paucibacillary leprosy.

Immunoprophylactic trial with combined Mycobacterium leprae/BCG vaccine against leprosy: preliminary results.

In an attempt to find a vaccine that gives greater and more consistent protection against leprosy than BCG vaccine, we compared BCG with and without killed Mycobacterium leprae in Venezuela. Close contacts of prevalent leprosy cases were selected as the trial population since they are at greatest risk of leprosy. Since 1983, 29,113 contacts have been randomly allocated vaccination with BCG alone or BCG plus 6 x 10(8) irradiated, autoclaved M leprae purified from the tissues of infected armadillos. We excluded contacts with signs of leprosy at screening and a proportion of those whose skin-test responses to M leprae soluble antigen (MLSA) were 10 mm or more (positive reactions). By July, 1991, 59 postvaccination cases of leprosy had been confirmed in 150,026 person-years of follow-up through annual clinical examinations of the trial population (31 BCG, 28 BCG/M leprae). In the subgroup for which we thought an effect of vaccination was most likely (onset more than a year after vaccination, negative MLSA skin-test response before vaccination), leprosy developed in 11 BCG recipients and 9 BCG/M leprae recipients; there were 18% fewer cases (upper 95% confidence limit [CL] 70%) in the BCG/M leprae than in the BCG alone group. For all cases with onset more than a year after vaccination irrespective of MLSA reaction the relative efficacy was 0% (upper 95% CL 54%; 15 cases in each vaccine group). Retrospective analysis of data on the number of BCG scars found on each contact screened suggested that BCG alone confers substantial protection against leprosy (vaccine efficacy 56%, 95% CL 27-74%) and there was a suggestion that several doses of BCG offered additional protection. There is no evidence in the first 5 years of follow-up of this trial that BCG plus M leprae offers substantially better protection against leprosy than does BCG alone, but the confidence interval on the relative efficacy estimate is wide.