Study On The Genotype Of Mycobacterium Tuberculosis Isolates From Chilidren Of Chongqing And Its Drug Resistance

Background and objective:TB is a serious public health problem of infectious diseases in recent years, survey data show that TB infection rate is 0.72% in 0-14-year-old children, no significant decrease compared with previous years. And in the western region, children with active TB prevalence was significantly higher than in the eastern region. The monitoring data from different sources has demonstrated the hotsPot of drug resistant TB in some Chinese areas. Drug resistant TB could directly cause the high prevalence and mortality of TB and meanwhile the elongation of treatment period and increase in treatment cost. Now we have used molecular epidemiological for surveillance of tuberculosis.These approahes have great significance for understanding drug-resistant TB transmission in the situation of children. With high resolution and ease of performance advantages, Mycobacterium tuberculosis interspersed repetitive unit genotyping (Mycobacterial interspersed repetitive units, MIRU) has been recommended by the U.S. Centre for Disease Control and Prevention for the genotyping of Mycobacterium tuberculosis preferred method. We explore the Chongqing Children's patients in clinical isolates of Mycobacterium tuberculosis molecular epidemiological features and relationship with drug resistance by MIRU genotyping.Methods:150 children diagnosed with culture-confirmed TB in Children's hospital of Chongqing Medical University were included from From July 2003 to December 2008.We use the absolute concentration method for drug susceptibility tests to all isolates and determine the standard reference on the results by Guide to Diagnosis and Treatment of Tuberculosis. Meantime we type all isolates by mycobacterial interspersed repetitive units(MIRU) and analysis the relation between drug resistance and genotype.Results:119 strains (79.3%) were sensitive to all the five drugs (INH, RFP, SM, EMB, PZA), on the SM, INH, RFP, PZA, EMB of the number of drug-resistant strains were 18 (12%), 16 (10.7), 13 (8.7%), 4 (2.7%), 4 (2.7%), the number of multidrug-resistant strains is 10 (6.7%). The 150 strains were typed to 89 distinct MIRU patterns.and 65 isolates were unique.85 strains were grouped into 24 different MIRU cluster.the MIRU genotype of the largest cluster was 223325173533. Drug resistant M. tuberculosis wasn't associated with cluster type.Conclusion:223325173533 genotype was perhaps the main epidemic strains for children in chongqing. drug-resistance might be no relationship with the clustering genotype.