RESUMEN
In this study, we aimed to investigate the molecular epidemiology and drug-resistance profiles of tuberculosis (TB) in Luodian, an area with highest TB incidence and limited healthcare resources in Guizhou, China. The passive case finding strategy was used to identify suspected pulmonary TB with symptoms, and individuals with positive Mycobacterium tuberculosis (MTB) culture were enrolled from May 22, 2018 to April 21, 2019. All the 107 cases except three came from nine towns, including 55.1% from Longping and Bianyang. The phylogeny tree showed that 53.3% of strains were Lineage 2 (Beijing genotype), while 46.7% were Lineage 4 (Euro-American genotype). Among Lineage 2 strains, 66.7% were of "modern" Beijing type. Seven clusters with genomic distance within 12 SNPs were identified. The clusters included 14 strains, accounting for a clustering rate of 13.1%. The distance separating the clustered cases was between 2.1 and 71.0 km (Km), with an average paired distance of 21.8 Km (interquartile range, 2.8-38.0 Km). Based on the gene mutations associated with drug-resistance, we predicted that 4.8% of strains were resistant to isoniazid, 3.7% to rifampicin, and 3.7% to streptomycin; only one strain (0.9%) had multidrug resistance (MDR). This study found low drug-resistance rates in Luodian, and the sub-lineage of the "modern" Beijing branch has recent expansion in Luodian. This work may also serve as a genomic baseline to assess the evolution and spread of MTB in Guizhou.
Asunto(s)
Antibacterianos/farmacología , Farmacorresistencia Bacteriana/genética , Isoniazida/farmacología , Rifampin/farmacología , Estreptomicina/farmacología , Tuberculosis Resistente a Múltiples Medicamentos/epidemiología , Tuberculosis Pulmonar/epidemiología , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , China/epidemiología , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Filogenia , Prevalencia , Tuberculosis Resistente a Múltiples Medicamentos/prevención & control , Tuberculosis Pulmonar/prevención & control , Secuenciación Completa del Genoma , Adulto JovenRESUMEN
OBJECTIVE: Molecular epidemiology is a promising tool for understanding tuberculosis transmission dynamics but has not been sufficiently utilised in Asian countries including Japan. The aim of this study was to estimate the proportion of TB cases attributable to recent transmission and to identify risk factors of genotype clustering and the development of large clusters within 3 years in an urban setting in Japan. DESIGN AND SETTING: Long-term cross-sectional observational study combining the characteristics of patients with culture-positive TB notified in Shinjuku City, Tokyo (2002-2013), with genotype data of Mycobacterium tuberculosis. PRIMARY OUTCOME MEASURE: Genotype clustering rate and association between genotype clustering status and explanatory variables. RESULTS: Among 1025 cases, 515 were localised within 113 genotype clusters. The overall clustering rate was 39.2%. Significantly higher rates were found in patients aged <40 years (adjusted odds ratio (aOR)=1.73, 95% CI 1.23 to 2.44), native Japanese individuals (aOR=3.90, 95% CI 2.27 to 6.72), full-time workers (aOR=1.63, 95% CI 1.17 to 2.27), part-time/daily workers (aOR=2.20, 95% CI 1.35 to 3.58), individuals receiving public assistance (aOR=1.81, 95% CI 1.15 to 2.84) and homeless people (aOR=1.63, 95% CI 1.02 to 2.62). A significant predictor of large genotype clusters within 3 years was a registration interval ≤2 months between the first two cases in a cluster. CONCLUSION: Our results indicated that a large proportion of patients with culture-positive TB were involved in the recent TB transmission chain. Foreign-born persons still have a limited impact on transmission in the Japanese urban setting. Intensified public health interventions, including the active case finding, need to focus on individuals with socioeconomic risk factors that are significantly associated with tuberculosis transmission and clusters with shorter registration intervals between the first two cases.
Asunto(s)
Mycobacterium tuberculosis/genética , Tuberculosis/transmisión , Salud Urbana , Adulto , Anciano , Anciano de 80 o más Años , Análisis por Conglomerados , Estudios Transversales , Femenino , Genotipo , Humanos , Masculino , Persona de Mediana Edad , Epidemiología Molecular , Mycobacterium tuberculosis/aislamiento & purificación , Factores de Riesgo , Tokio/epidemiología , Tuberculosis/diagnóstico , Tuberculosis/epidemiología , Tuberculosis/microbiologíaRESUMEN
Tuberculosis caused by resistant M. tuberculosis strains poses a serious threat as it requires prolonged and costly treatment and has high mortality rate. In order to investigate resistance to antituberculous drugs in Croatia, we analysed all resistant M. tuberculosis strains isolated from patients' samples in period 2010-2014 (1 strain per patient). Out of 2384 M. tuberculosis strains, we identified 88 (3.69 %) resistant strains. The analysis included resistance patterns, resistance conferring mutations and, according to MIRU-VNTR analysis, clustering and global lineages distribution. Relatively high number of strains was monoresistant, especially to isoniazid, while there were only six multiresistant strains. Among 59 strains with any pattern that includes resistance to isoniazid, a total of 22 (37.29 %) had resistance conferring mutation in katG gene (S315T), 23 (38.98 %) in inhA promoter region (C-15T) and 14 (23.73 %) had none of these mutations. The observed clustering rate of resistant strains was 28.41 %, and the most common global lineage was Euro-American (75 %).