Infectivity ofMycobacterium tuberculosisGenotypes and Outcome of Contact Investigation in Classroom in Guangxi, China

Abstract

Objective. To evaluate the infectivity of Mycobacterium tuberculosis (M.tb) genotypes of index cases in the classroom of adolescent schools in Guangxi, China. Methods. Adolescent school tuberculosis (TB) contact investigations were conducted for all reported index TB cases from November 2016 to December 2017 in Guangxi, China. Genotypes of index cases and contact cases were identified by 15-loci mycobacterial interspersed repetitive units–variable number tandem repeat and spoligotyping. Outcome variable was 5 levels’ order of tuberculin skin test (TST) results to new active TB [0-5 mm, 6-9 mm, 10-14 mm, ≥ 15 mm (without TB), and ≥15 mm (with TB)]. Multivariate ordered logistic regression analysis was performed to evaluate the independent effect of genotypes of index case on contact screening outcome. Results. Beijing genotype occurred more commonly in female index patients. One genotypic cluster of two index cases and one cluster of two contact cases were detected. The association between infectivity of Beijing genotype of index cases and outcome of contact investigation was statistically significant in univariate analysis but no so after adjustment for characteristics of contacts and sex of index cases (P value=0.057). Female index cases increased the chance for TB infection/being active TB among contacts (ordinal odds ratio = 1.39, 95% confidence interval: 1.21, 1.60). Contacts who studied in the middle school, who with non-Han ethnicity and who without BCG scar had increased risk for TB infection/being active TB. Conclusion. There was not enough evidence from our data to support that Beijing strains were more infective than non-Beijing strains in TB transmission in school setting.

Mycobacterium tuberculosis Infection in School Contacts of Tuberculosis Cases: A Systematic Review and Meta-Analysis

“…The primary characteristics of the studies included in the review are summarized in Table 1. In total, 28 studies with 54,707 school contacts were included in the pooled prevalence of M. tuberculosis infection, of which 19 studies were from China, [13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] three were from Italy, [32][33][34] two were from Korea, 35,36 and four studies each were from Iran, 37 Japan, 38 Sweden, 39 and the United States, 40 respectively. In regard to study design, 15 were cross-sectional studies and 11 were retrospective studies.…”

Transmission of multidrug-resistant Mycobacterium tuberculosis in Wuhan, China

“…The genotyping method included MIRU-VNTR, DTM-PCR and drug resistance-associated genes sequencing. The genotyping of MTB plays an important role in tracing the source of infection in contact investigation, [16,17] distinguishing exogenous infection and endogenous relapse, [18] and outbreak investigation, [19,20] which can make up for the shortcomings of traditional epidemiological survey. Identification of Beijing family genotype is often the first step of genotyping MTB.…”

How to Optimize Tuberculosis Health Education in College Under the New Situation? Based on a Cross-Sectional Study Among Freshmen of a Medical College in Guangxi, China

“…Guangxi Zhuang Autonomous Region is an underdeveloped southwestern region of China where the TB epidemic is relatively serious. Studies have shown that TB cases among students are mainly concentrated in high school and college students ( 14 , 15 ). Hence, improving the cognition on TB among college students is an important measure to control the TB epidemic in colleges of Guangxi ( 12 ).…”