RESUMO
In 2003, the incidence of tuberculosis in Argentina showed an increase compared to 2002. The severe national crisis at the end of the 90s has probably strongly contributed to this situation. The goal of this work was to estimate the extent of the spread of the most predominant Mycobacterium tuberculosis strains and to assess the spread of predominant M. tuberculosis clusters as determined by spoligotyping and IS6110 RFLP. The study involved 590 pulmonary, smear-positive TB cases receiving medical attention at health centers and hospitals in Northern Buenos Aires (NBA) suburbs, from October 2001 to December 2002. From a total of 208 clinical isolates belonging to 6 major clusters, 63 (30.2%) isolates had identical spoligotyping and IS6110 RFLP pattern. Only 22.2% were shown to have epidemiological connections with another member of their respective cluster. In these major clusters, 30.2% of the 208 TB cases studied by both molecular techniques and contact tracing could be convincingly attributable to a recently acquired infection. This knowledge may be useful to assess the clonal distribution of predominant M. tuberculosis clusters in Argentina, which may make an impact on TB control strategies.
Assuntos
Transmissão de Doença Infecciosa , Mycobacterium tuberculosis/genética , Tuberculose/microbiologia , Adulto , Argentina/epidemiologia , Técnicas de Tipagem Bacteriana/métodos , Criança , Análise por Conglomerados , Elementos de DNA Transponíveis/genética , DNA Bacteriano/genética , Feminino , Genótipo , Infecções por HIV/epidemiologia , Pessoal de Saúde , Humanos , Incidência , Masculino , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Sequências Repetitivas de Ácido Nucleico , População Suburbana , Tuberculose/epidemiologia , Tuberculose/transmissão , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/transmissãoRESUMO
In 2003, the incidence of tuberculosis in Argentina showed an increase compared to 2002. The severe national crisis at the end of the 90s has probably strongly contributed to this situation. The goal of this work was to estimate the extent of the spread of the most predominant Mycobacterium tuberculosis strains and to assess the spread of predominant M. tuberculosis clusters as determined by spoligotyping and IS6110 RFLP. The study involved 590 pulmonary, smear-positive TB cases receiving medical attention at health centers and hospitals in Northern Buenos Aires (NBA) suburbs, from October 2001 to December 2002. From a total of 208 clinical isolates belonging to 6 major clusters, 63 (30.2%) isolates had identical spoligotyping and IS6110 RFLP pattern. Only 22.2% were shown to have epidemiological connections with another member of their respective cluster. In these major clusters, 30.2% of the 208 TB cases studied by both molecular techniques and contact tracing could be convincingly attributable to a recently acquired infection. This knowledge may be useful to assess the clonal distribution of predominant M. tuberculosis clusters in Argentina, which may make an impact on TB control strategies.
La incidencia de la tuberculosis en Argentina mostró en 2003 un incremento en comparación con 2002. La grave crisis nacional a fines de los 90 ha probablemente contribuido en gran medida a esta situación. El objetivo del presente trabajo fue determinar la diversidad genética de aislamientos de Mycobacterium tuberculosis y el grado de dispersión de algunas cepas mayoritarias genéticamente relacionadas. El estudio involucró 590 aislamientos clínicos provenientes de muestras respiratorias con examen directo positivo, de pacientes atendidos en los hospitales y centros de salud que conforman la región Gran Buenos Aires Norte (NBA), de octubre de 2001 a diciembre de 2002. De 208 aislamientos que se encontraron en los 6 mayores clusters, 63 (30,2%) tenían patrones idénticos de spoligotyping y de IS6110 RFLP. En el 22,2% de los casos fue posible verificar la conexión epidemiológica con otro miembro del respectivo cluster. Concluimos que el 30,2% de estos agrupamientos principales pueden ser atribuidos a una infección reciente. Estos resultados pueden ser útiles para determinar la distribución clonal de los grupos predominantes de M. tuberculosis en Argentina, lo que puede impactar en las estrategias de control de la tuberculosis.
Assuntos
Adulto , Criança , Feminino , Humanos , Masculino , Transmissão de Doença Infecciosa , Mycobacterium tuberculosis/genética , Tuberculose/microbiologia , Argentina/epidemiologia , Técnicas de Tipagem Bacteriana/métodos , Análise por Conglomerados , Elementos de DNA Transponíveis/genética , DNA Bacteriano/genética , Genótipo , Pessoal de Saúde , Infecções por HIV/epidemiologia , Incidência , Mycobacterium tuberculosis/classificação , Mycobacterium tuberculosis/isolamento & purificação , Reação em Cadeia da Polimerase/métodos , Sequências Repetitivas de Ácido Nucleico , População Suburbana , Tuberculose Resistente a Múltiplos Medicamentos/epidemiologia , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Resistente a Múltiplos Medicamentos/transmissão , Tuberculose/epidemiologia , Tuberculose/transmissãoRESUMO
During a population-based study to genotype isolates of Mycobacterium tuberculosis from Buenos Aires Northern suburbs, we found isolates with molecular patterns related to those of the Beijing genotype. Five out of 590 (0.85%) patients had isolates with spoligopattern identical to that of the Beijing family. Since two of these isolates showed identical IS6110RFLP pattern, we found only four different patterns containing 11 to 19 bands. The isolates were obtained from young people (including a 7 years-old child) who were born in Argentina, and were living in a small area of our region. However, conventional contact tracing did not prove epidemiological linkage among them. These isolates were fully drug-susceptible to the first-line drugs. The comparison of the IS6110RFLP patterns from our isolates against a set of 19 reference Beijing patterns from the RIVM (The Netherlands) confirmed that the strains belonged to the Beijing lineage. These findings might be partially explained by the important migration phenomena occurred during the last decade. Further surveillance studies would help in the following of Beijing family strain dissemination in our community.
Assuntos
Mycobacterium tuberculosis/classificação , Tuberculose/microbiologia , Adolescente , Adulto , Argentina/epidemiologia , Ásia/etnologia , Técnicas de Tipagem Bacteriana , Criança , Infecções Comunitárias Adquiridas/epidemiologia , Infecções Comunitárias Adquiridas/microbiologia , Busca de Comunicante , DNA Bacteriano/isolamento & purificação , Emigração e Imigração , Genótipo , Humanos , Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/isolamento & purificação , Filogenia , Reação em Cadeia da Polimerase , Tuberculose/epidemiologia , População UrbanaRESUMO
During a population-based study to genotype isolates of Mycobacterium tuberculosis from Buenos Aires Northern suburbs, we found isolates with molecular patterns related to those of the Beijing genotype. Five out of 590 (0.85
) patients had isolates with spoligopattern identical to that of the Beijing family. Since two of these isolates showed identical IS6110RFLP pattern, we found only four different patterns containing 11 to 19 bands. The isolates were obtained from young people (including a 7 years-old child) who were born in Argentina, and were living in a small area of our region. However, conventional contact tracing did not prove epidemiological linkage among them. These isolates were fully drug-susceptible to the first-line drugs. The comparison of the IS6110RFLP patterns from our isolates against a set of 19 reference Beijing patterns from the RIVM (The Netherlands) confirmed that the strains belonged to the Beijing lineage. These findings might be partially explained by the important migration phenomena occurred during the last decade. Further surveillance studies would help in the following of Beijing family strain dissemination in our community.
RESUMO
During a population-based study to genotype isolates of Mycobacterium tuberculosis from Buenos Aires Northern suburbs, we found isolates with molecular patterns related to those of the Beijing genotype. Five out of 590 (0.85
) patients had isolates with spoligopattern identical to that of the Beijing family. Since two of these isolates showed identical IS6110RFLP pattern, we found only four different patterns containing 11 to 19 bands. The isolates were obtained from young people (including a 7 years-old child) who were born in Argentina, and were living in a small area of our region. However, conventional contact tracing did not prove epidemiological linkage among them. These isolates were fully drug-susceptible to the first-line drugs. The comparison of the IS6110RFLP patterns from our isolates against a set of 19 reference Beijing patterns from the RIVM (The Netherlands) confirmed that the strains belonged to the Beijing lineage. These findings might be partially explained by the important migration phenomena occurred during the last decade. Further surveillance studies would help in the following of Beijing family strain dissemination in our community.
RESUMO
In the last decade, an unprecedented genetic diversity has been disclosed among Mycobacterium tuberculosis strains found worldwide. However, well-conserved genotypes seem to prevail in areas with high incidence of tuberculosis. As this may be related to selective advantages, such as advanced mechanisms to circumvent [M. bovis Bacille Calmette-Guerin (BCG)-induced] host defence mechanisms, we investigated the influence of strain diversity on the course of experimental disease. Twelve M. tuberculosis strains, representing four major genotype families found worldwide today, and the laboratory strain H37Rv were each used to infect BALB/c mice by direct intratracheal injection. Compared with H37Rv, infections with Beijng strains were characterized by extensive pneumonia, early but ephemeral tumour necrosis factor-alpha (TNF-alpha) and inducible isoform of nitric oxide synthetase (iNOS) expression, and significantly higher earlier mortality. Conversely, Canetti strains induced limited pneumonia, sustained TNF-alpha and iNOS expression in lungs, and almost 100% survival. Strains of the Somali and the Haarlem genotype families displayed less homogeneous, intermediate rates of survival. Previous BCG vaccination protected less effectively against infection with Beijing strains than against the H37Rv strain. In conclusion, genetically different M. tuberculosis strains evoked markedly different immunopathological events. Bacteria with the Beijing genotype, highly prevalent in Asia and the former USSR, elicited a non-protective immune response in mice and were the most virulent. Future immunological research, particularly on candidate vaccines, should include a broad spectrum of M. tuberculosis genotypes rather than a few laboratory strains.
Assuntos
Mycobacterium tuberculosis/genética , Mycobacterium tuberculosis/patogenicidade , Tuberculose Pulmonar/microbiologia , Animais , Vacina BCG/administração & dosagem , Ensaio de Unidades Formadoras de Colônias , Citocinas/análise , Suscetibilidade a Doenças , Genoma Bacteriano , Genótipo , Pulmão/imunologia , Pulmão/patologia , Camundongos , Camundongos Endogâmicos BALB C , Modelos Animais , Óxido Nítrico Sintase/análise , Óxido Nítrico Sintase Tipo II , Polimorfismo de Fragmento de Restrição , Tuberculose Pulmonar/imunologia , Tuberculose Pulmonar/patologiaRESUMO
SETTING: Cetrangolo Hospital, Vicente Lopez, Argentina, 1995-1999. OBJECTIVE: To describe a home-made reverse-line blot hybridisation assay for the detection of rifampicin resistance-associated mutations in the rpoB gene of Mycobacterium tuberculosis, and to evaluate the usefulness of this rifampicin oligonucleotide, or 'RIFO' assay, to predict rifampicin resistance. DESIGN: A total of 135 M. tuberculosis isolates from the Cetrangolo Hospital were tested using the RIFO assay, the proportion method and the Mycobacterial Growth Indicator Tube (MGIT 960). In addition, 120 drug-susceptible isolates from the Netherlands were included. RESULTS: The results obtained with the proportion method and the MGIT 960 system were in full agreement. In the RIFO assay, 90 of the 97 rifampicin-resistant isolates were correctly identified (sensitivity 92.8%, positive predictive value 100%). All of the drug-susceptible isolates were correctly predicted by the RIFO assay. CONCLUSIONS: With this home-made molecular test, rifampicin resistance in M. tuberculosis can be predicted in colonies isolated in culture in only 1 day, and can therefore shorten the laboratory turn around time for rifampicin susceptibility testing by weeks. In principle the test can also be applied directly to Zichl-Neelsen slides and clinical material, as has been demonstrated for another reverse-line blot-based assay for M. tuberculosis, spoligotyping.
Assuntos
Antibióticos Antituberculose/uso terapêutico , RNA Polimerases Dirigidas por DNA/genética , Mycobacterium tuberculosis/isolamento & purificação , Hibridização de Ácido Nucleico/métodos , Rifampina/uso terapêutico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Pulmonar/microbiologia , DNA Bacteriano/análise , Humanos , Testes de Sensibilidade Microbiana/métodos , Mycobacterium tuberculosis/genética , Reação em Cadeia da Polimerase , Sensibilidade e Especificidade , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Pulmonar/tratamento farmacológicoRESUMO
Strains of Mycobacterium tuberculosis isolated from 219 different tuberculosis patients, 115 from patients residing in Rio de Janeiro, 79 from Rio Grande do Sul and the remaining from other regions of the country, were analyzed by IS6110-restriction fragment length polymorphism fingerprinting. The IS6110-DNA patterns from these strains were highly polymorphic: 174 different patterns were observed and 25 patterns were shared by 70 isolates (32%). Most strains (93.4%) had multicopy patterns and only 17% of clustered strains had less than six IS6110 copies. Strain clustering was significantly higher for isolates from Rio Grande do Sul (36.7%) in comparison with strains from Rio de Janeiro (22.6%), but only when using high stringency during cluster analysis. Upon screening of an international database containing 3,970 fingerprints of M. tuberculosis strains, 15% of the patterns of Brazilian strains (21% of the strains) were identical to a fingerprint of an isolate from another country and one particular eight-band pattern forming the largest Brazilian cluster was detected in seven additional countries, suggesting that international transmission of tuberculosis from and to Brazil could be occurring frequently. Alternatively,preferential use of certain IS6110 integration sites could also be important in high-copy number strains, having important consequences for the use of databases for epidemiological studies on a large scale.
Assuntos
Impressões Digitais de DNA , Elementos de DNA Transponíveis , Bases de Dados Factuais , Mycobacterium tuberculosis/classificação , Polimorfismo de Fragmento de Restrição , Tuberculose Pulmonar/microbiologia , Técnicas de Tipagem Bacteriana , Brasil , Humanos , Cooperação Internacional , Mycobacterium tuberculosis/genética , Tuberculose Pulmonar/transmissãoRESUMO
To disclose risk factors for active tuberculosis transmission in the Netherlands, restriction fragment length polymorphism (RFLP) patterns of 78% of the Mycobacterium tuberculosis isolates, from the period 1993-1997, were analyzed. Of the respective 4266 cases, 46% were found in clusters of isolates with identical RFLPs, and 35% were attributed to active transmission. The clustering percentage increased strongly with the number of isolates; taking this into account, fewer cases were clustered than has been reported in other studies. Contact investigations in the five largest clusters of 23-47 patients suggested epidemiological linkage between cases. Of patients identified through contact tracing, 91% were clustered. Demographic risk factors for active transmission of tuberculosis included male sex, urban residence, Dutch and Surinamese nationality, and long-term residence in the Netherlands. Human immunodeficiency virus infection was not an independent risk factor for active transmission. Isoniazid-resistant strains were relatively less frequently clustered, suggesting that these generated fewer secondary cases.
Assuntos
Mycobacterium tuberculosis/genética , Tuberculose/epidemiologia , Adulto , Idoso , Análise por Conglomerados , Comorbidade , Busca de Comunicante , Demografia , Etnicidade , Feminino , Infecções por HIV/epidemiologia , Humanos , Masculino , Pessoa de Meia-Idade , Epidemiologia Molecular , Mycobacterium tuberculosis/isolamento & purificação , Países Baixos/epidemiologia , Polimorfismo de Fragmento de Restrição , Fatores de Risco , Suriname/etnologia , Tuberculose/microbiologia , Tuberculose/transmissão , População UrbanaRESUMO
SETTING: Molecular typing has become an important tool for examining the extent of active transmission of tuberculosis. OBJECTIVES: To examine transmission of tuberculosis in Cuba using IS6110 restriction fragment length polymorphism (RFLP) typing and to evaluate the utility of spoligotyping. DESIGN: One hundred and sixty Mycobacterium tuberculosis strains isolated over a one year period in Cuba were subjected to RFLP and spoligotyping. RESULTS: Forty-eight percent of the isolates were found in 19 clusters of strains with identical RFLP patterns. In general, cluster sizes were limited, except for two large institutional outbreaks. Age was strongly inversely correlated to clustering. Most streptomycin-resistant isolates were found in clusters. Fifteen spoligotype clusters comprised 78% of the isolates. Significantly different IS6110 RFLP types subdivided 11 spoligotype clusters, whereas none of the IS6110 clusters were subdivided by spoligotyping. CONCLUSIONS: Considering the short study period, 48% clustering is high, indicating that recent transmission plays an important role in Cuba. Although resistance is still a minor problem, transmission of streptomycin-resistant strains occurs. The high polymorphism observed with IS6110 RFLP indicates that this marker is useful for future molecular epidemiological studies in Cuba. Spoligotyping appeared less suitable for population-based studies.