Prevalence and risk factors of mixed Mycobacterium tuberculosis complex infections in China.
OBJECTIVE
Mixed infections have been considered as a potential obstacle for tuberculosis treatment and control. To date, few studies have been done to determine the rate of mixed infections of Mycobacterium tuberculosis in China.


METHODS
In this study, we used the standard 24-loci MIRU-VNTR method to genotype the representative M. tuberculosis isolates from the national drug-resistant survey conducted in China. A total of 3248 M. tuberculosis complex (MTBC) strains had complete 24-loci MIRU-VNTR results and available for the analyses.


RESULTS
Overall, MIRU-VNTR typing identified 115 (3.5%) isolates as being mixed MTBC infections in China. Statistical analysis revealed that mixed infections were significantly more likely to occur in men than women. Compared with the percentage of mixed infection from patients aged 45-56 years, the percentages of mixed infections were higher among patients aged 25-44 years [OR (95% CI): 1.844(1.129-3.014)] and old patients [older than 65 years OR (95% CI): 1.908(1.097-3.319)]. In addition, significantly higher frequencies of hemoptysis (P = 0.022) and chest pain (P = 0.012) were observed among mixed infections, using patients infected with a single strain as a reference.


CONCLUSIONS
In conclusion, this study has provided the first comprehensive understanding of mixed MTBC infections in China, which will be essential to generate the effective TB control strategies.
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Yu
Y
Pang
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Yang
Y
Zhou
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Shengfen
S
Wang
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Yuanyuan
Y
Song
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Xichao
X
Ou
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China.
Bing
B
Zhao
Respiratory Diseases Department of Nanlou, Chinese People's Liberation Army General Hospital, Beijing, China.
Zhijian
Z
Zhang
National Center for Tuberculosis Control and Prevention, Chinese Center for Disease Control and Prevention, Beijing, China. Electronic address: zhaoyanlin@chinatb.org.
Yanlin
Y
Zhao
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002681:China / Q000453:epidemiology; D060085:Coinfection / Q000453:epidemiology* / Q000382:microbiology*; D005260:Female; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D017720:Molecular Epidemiology; D058889:Molecular Typing; D009169:Mycobacterium tuberculosis / Q000145:classification* / Q000235:genetics / Q000302:isolation & purification; D015995:Prevalence; D012307:Risk Factors; D014376:Tuberculosis / Q000453:epidemiology* / Q000382:microbiology*; D055815:Young Adult
China; Mixed infection; Tuberculosis