Migration and tuberculosis transmission in a middle-income country: a cross-sectional study in a central area of São Paulo, Brazil.

BACKGROUND: Little is known about the impact of growing migration on the pattern of tuberculosis (TB) transmission in middle-income countries. We estimated TB recent transmission and its associated factors and investigated the presence of cross-transmission between South American migrants and Brazilians. METHODS: We studied a convenient sample of cases of people with pulmonary TB in a central area of São Paulo, Brazil, diagnosed between 2013 and 2014. Cases with similar restriction fragment length polymorphism (IS6110-RFLP) patterns of their Mycobacterium tuberculosis complex isolates were grouped in clusters (recent transmission). Clusters with both Brazilian and South American migrants were considered mixed (cross-transmission). Risk factors for recent transmission were studied using logistic regression. RESULTS: Isolates from 347 cases were included, 76.7% from Brazilians and 23.3% from South American migrants. Fifty clusters were identified, which included 43% South American migrants and 60.2% Brazilians (odds ratio = 0.50, 95% confidence interval = 0.30-0.83). Twelve cross-transmission clusters were identified, involving 24.6% of all clustered cases and 13.8% of all genotyped cases, with migrants accounting for either an equal part or fewer cases in 11/12 mixed clusters. CONCLUSIONS: Our results suggest that TB disease following recent transmission is more common among Brazilians, especially among those belonging to high-risk groups, such as drug users. Cross-transmission between migrants and Brazilians was present, but we found limited contributions from migrants to Brazilians in central areas of São Paulo and vice versa.

Mycobacterium tuberculosis in a HIV-1-infected population from Southeastern Brazil in the HAART era.

OBJECTIVE: To evaluate retrospectively the microbiological profile of Mycobacterium species isolated from HIV-infected patients attending the HIV/TB reference health care units in São José do Rio Preto, Brazil. METHOD: Retrospective evaluation of all HIV-1 positive patients whose IAL-SJRP laboratorial analysis was positive for Mycobacterium sp. after diagnosis of HIV Infection, from January 2000 to December 2006. RESULTS: Of 198 patients, acid-fast staining detected mycobacteria early in 41%. Culture revealed 52.5% to be infected with Mycobacterium tuberculosis (MT). 42.4% had non-tuberculous mycobacteria (NTM) and 5.1% had MT/NTM positive cultures. Eleven per cent of MT strains were resistant to at least one of the antimycobacterial drugs and 3.1% were multidrug resistant. 39.4% of isolated mycobacteria were NTM species. CONCLUSION: Our data may serve as a starting point for further comparisons with other Brazilian regions and other developing countries. The data may provide important clues to the future understanding, prevention and control of such co-infections around the world.

Recombinant interleukin-4-treated macrophages, epithelioid cell surrogates, harbor and arrest Mycobacterium avium multiplication in vitro.

Our group has previously described that murine peritoneal macrophages treated in vitro for 7 days with recombinant interleukin-4 (rIL-4) acquire morphological and functional characteristics of epithelioid cells (ECs) found in granulomatous lesions. Although EC function has not been clarified so far, it has been suggested that these cells could present antigens and control multiplication of mycobacteria. These aspects have been addressed here using in vitro EC surrogates. Using immunocytochemistry and immunofluorescence methods, we have observed an increased expression of CD11b, CD54, CD86 and CD40 molecules on rIL-4-treated macrophages when compared to untreated ones. Cytokine-treated cells were less phagocytic for latex beads (P<0.03) and more pinocytic for dextran particles than untreated macrophages. T-cell lymphoproliferation assays using ovalbumin (OVA) and Mycobacterium avium as antigens showed that both cultured macrophages were equally efficient as antigen presenting cells (APCs). However, M. avium antigens were better presented in vivo by EC surrogates (P<0.01). Both macrophage cultures were similarly infected by M. avium. However, while the infection level was maintained in the cytokine-treated population, untreated macrophages showed a progressive increase in the number of bacilli/cell with time (P<0.01) and a reduction of about 65% in cell population. After 96 h of M. avium infection, untreated cells secreted higher amounts of tumor necrosis factor-alpha (P<0.005) while rIL-4-treated macrophages showed higher, although not significant, transforming growth factor-beta production. Also, EC surrogates produced less nitric oxide than control macrophages (P<0.05). Hence, EC surrogates restrain M. avium growth and act as APCs in vitro and in vivo.

Population structure and circulating genotypes of drug-sensitive and drug-resistant Mycobacterium tuberculosis clinical isolates in São Paulo state, Brazil.

São Paulo is the most populous Brazilian state and reports the largest number of tuberculosis cases in the country annually (over 18,500). This study included 193 isolates obtained during the 2nd Nationwide Survey on Mycobacterium tuberculosis Drug Resistance that was conducted in São Paulo state and 547 isolates from a laboratory based study of drug resistance that were analyzed by the Mycobacteria Reference Laboratory at the Institute Adolfo Lutz. Both studies were conducted from 2006 to 2008 and sought to determine the genetic diversity and pattern of drug resistance of M. tuberculosis isolates (MTC) circulating in São Paulo. The patterns obtained from the spoligotyping analysis demonstrated that 51/740 (6.9%) of the isolates corresponded to orphan patterns and that 689 (93.1%) of the isolates distributed into 144 shared types, including 119 that matched a preexisting shared type in the SITVIT2 database and 25 that were new isolates. A total of 77/144 patterns corresponded to unique isolates, while the remaining 67 corresponded to clustered patterns (n=612 isolates clustered into groups of 2-84 isolates each). The evolutionarily ancient PGG1 lineages (Beijing, CAS1-DEL, EAI3-IND, and PINI2) were rarely detected in São Paulo and comprised only 13/740, or 1.76%, of the total isolates; all of the remaining 727/740, or 98.24%, of the MTC isolates from São Paulo state were from the recent PGG2/3 evolutionary isolates belonging to the LAM, T, S, X, and Haarlem lineages, i.e., the Euro-American group. This study provides the first overview of circulating genotypes of M. tuberculosis in São Paulo state and demonstrates that the clustered shared types containing seven or more M. tuberculosis isolates that are spread in São Paulo state included both resistant and susceptible isolates.