The assumption that Mycobacterium tuberculosis infections should be considered clonally homogeneous has been weakened in the last few years. Recent studies have shown (i) the isolation of different M. tuberculosis strains from sequential episodes, (ii) mixed infections by two M. tuberculosis strains, and (iii) genetic variations in M. tuberculosis subpopulations due to microevolution events. Nevertheless, it is unknown whether clonal heterogeneity could be found in the initial steps of M. tuberculosis infection, i.e., the primary infection. In the present study we analyzed the clonal composition of the M. tuberculosis isolates causing primary infections in children. Cultures were clonally homogeneous in most cases (11 of 12). In 1 of the 12 cases (8.3%), clonal heterogeneity among the M. tuberculosis isolates was found by spoligotyping and IS6110-based restriction fragment length polymorphism analysis. This case occurred in a 2-year-old child in whom microevolution events were unlikely and who had no risk factors for overexposure to M. tuberculosis. Clonal heterogeneity should also be considered in primary M. tuberculosis infections, including circumstances in which it is usually unexpected.In recent years, clonal heterogeneity in the Mycobacterium tuberculosis populations causing infections has been found more frequently than was initially expected. Different studies have shown that a relevant proportion of tuberculosis (TB) recurrences are caused by strains other than those involved in the first episode (1,3,4,7,9,11,13). Furthermore, mixed infections by more than one M. tuberculosis strain during the same episode have been reported (2, 4, 10, 14, 15), and we have found (8) that in some cases this polyclonality leads to compartmentalization of the infection, with different clones infecting respiratory and extrarespiratory sites. In addition, clonal heterogeneity has also been proposed to be the result of the acquisition of subtle genetic changes in an M. tuberculosis subpopulation due to microevolution events during the course of the infection (6).In general, clonal heterogeneity in an M. tuberculosis isolate is assumed to be the result of a superinfection in a previous TB episode by a new M. tuberculosis strain. This would lead to the simultaneous or sequential presence of two different strains in the same patient. In some cases, a simultaneous coinfection with more than one strain has been proved, but only in highrisk circumstances (2, 4). As far as the microevolution events causing clonal heterogeneity in the M. tuberculosis isolates are concerned, it has been proposed that a minimum time of progression of the infection is required to allow mutations and rearrangements to occur (5).Therefore, the circumstances in which clonal heterogeneity has been explored in TB are mainly restricted to (i) recurrences, (ii) superinfections of uncured cases, and (iii) cases in high-incidence settings. Our study aimed to analyze the clonal composition of M. tuberculosis isolates in a circumstance, pri- Microbiological metho...
The composition of the vaginal microbiota is an important health determinant. Several members of the phylum Actinobacteria have been implicated in bacterial vaginosis, a condition associated with many negative health outcomes. Here, we present 11 strains of vaginal Actinobacteria (now available through BEI Resources) along with draft genome sequences.
OBJECTIVE: To determine the existence of cross-reactions between Leishmania serology and mycobacteriosis in patients infected with HIV-1. PATIENTS AND METHODS: HIV-positive individuals, with culture-proven episodes of tuberculosis or disseminated Mycobacterium avium complex (MAC) infection, were identified from the data files of our microbiology laboratory. Patients were included if leishmania serology had been performed within a period of 2 months before and 1 month after the diagnosis of mycobacterial disease. RESULTS: We identified 106 cases of tuberculosis and 38 of disseminated MAC infection with concomitant leishmania serology in HIV-infected individuals. Among them, only two cases (1.8%), both with tuberculosis and without visceral leishmaniasis, showed positive leishmania serology. The two cases are discussed. CONCLUSIONS: We conclude that, in spite of its low sensitivity, serology is a useful diagnostic tool in co-infected patients, mainly because of its high specificity and the low rate of cross-reactivity with two of the most frequent causes of fever of unknown origin in HIV-positive patients from our area.
Molecular epidemiology of circulating clinical isolates is crucial to improve prevention strategies. The Spanish Working Group on multidrug resistant tuberculosis (MDR-TB) is a network that monitors the MDR-TB isolates in Spain since 1998. The aim of this study was to present the study of the MDR-TB and extensively drug-resistant tuberculosis (XDR-TB) patterns in Spain using the different recommended genotyping methods over time by a national coordinated system. Based on the proposed genotyping methods in the European Union until 2018, the preservation of one method, MIRU-VNTR, applied to selected clustered strains permitted to maintain our study open for 20 years. The distribution of demographic, clinical and epidemiological characteristics of clustered and non-clustered cases of MDR/XDR tuberculosis with proportion differences as assessed by Pearson’s chi-squared or Fisher’s exact test was compared. The differences in the quantitative variables using the Student's-t test and the Mann–Whitney U test were evaluated. The results obtained showed a total of 48.4% of the cases grouped in 77 clusters. Younger age groups, having a known TB case contact (10.2% vs 4.7%) and XDR-TB (16.5% vs 1.8%) were significantly associated with clustering. The largest cluster corresponded to a Mycobacterium bovis strain mainly spread during the nineties. A total of 68.4% of the clusters detected were distributed among the different Spanish regions and six clusters involving 104 cases were grouped in 17 and 18 years. Comparison of the genotypes obtained with those European genotypes included in The European Surveillance System (TESSy) showed that 87 cases had become part of 20 European clusters. The continuity of MDR strain genotyping in time has offered a widespread picture of the situation that allows better management of this public health problem. It also shows the advantage of maintaining one genotyping method over time, which allowed the comparison between ancient, present and future samples.
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