Absence Of An Association Between Mycobacterium Tuberculosis Beijing/W Lineage Strain Infection And Clinical Chracterization Of Pediatric Tuberculosis In Chongqing, China

Objective:To study the prevalence of clinical isolates of Beijing/W lineage in pediatric tuberculosis (TB) in Chongqing, and the association between strain family and clinical characterization of pediatric TB.Methods:105 children diagnosed with culture-confirmed TB in Children's Hospital of Chongqing Medical University were included from 1 January 2005 to 31 December 2007. All isolates were typed by mycobacterial interspersed repetitive units (MIRU) and deletion-targeted multiplex PCR (DTM-PCR). The medical records of children aged less than 18 years with cultured-confirmed tuberculosis were retrospectively reviewed. The data of clinical characterization including demographic characteristics, presenting symptoms, history of BCG vaccination, laboratory data image findings diagnosis and outcome were collected. Statistical analysis was performed using chi-squared test. Data are shown as mean±standard deviation or number (percentage).Results:MIRU typing identified 72 types that defined 17 clusters and 55 unique isolates. The largest cluster was 223325173533.Clinical isolates of Beijing/W lineage accounted for 64.8%.Children in rural was accounted for 68.8% of the cases. The majority of the children with TB were older than 0 years and less than 3 years. Extrapulmonary TB accounted for 66.7% of the cases, and the majority (51.4%) of extrapulmonary TB was tuberculous meningitis (TBM).There was no association between clinical characterization and Beijing/W lineage.Conclusion:The strain of Beijing/W lineage is the dominant genotype family in children with cultured-confirmed TB in Chongqing. Beijing/W and non-Beijing/W strains did not differ in their propensities to cause extrapulmonary TB in general or meningitis in particular, and there was no difference between children infected with Beijing/W strains and those infected with non-Beijing/W strains with respect to the clinical features.