Tuberculosis relapse is more common than reinfection in Beijing, China

Abstract

Background

Recurrent tuberculosis (TB) is a major health problem in countries with a high TB burden. It is very necessary to elucidate the situation of recurrent TB in Beijing, capital of China.

Objective

To determine the proportion of recurrent tuberculosis (TB) cases and to identify relapsed or reinfected cases, as well as risk factors associated with recurrence in Beijing.

Methods

We conducted a retrospective study that included all TB cases in Beijing that were successfully treated from 2013 to 2015. Recurrence due to relapse or reinfection was determined using the variable number of tandem repeats (VNTR) method. Risk factors associated with recurrence were analysed.

Results

Tuberculosis recurred in 275 of the 4043 successfully treated TB patients, giving a recurrence rate of 6.8% (275/4043). 190 of the 275 cases were culture positive in both instances, and genotyping results for both episodes were available for 58 of these patients. The cultured isolates from 40 of the 58 recurrent cases (69%) had identical genotypic patterns in both episodes, indicating a relapse. 31% (18/58) had different genotypes, indicating reinfection by a new strain and suggested recent transmission. Those people in the 30–59 age group (p < .001), and those retreated for pulmonary TB (p < .001) were more likely to have TB recurrence.

Conclusion

Our results indicate that relapse was more common than reinfection in recurrent TB cases in Beijing from 2013 to 2015. Age and retreatment were found to be risk factors for TB recurrence.

Keywords:

• Tuberculosis
• recurrence
• relapse
• reinfection
• genotyping

Acknowledgements

We are grateful to Dr. Y. X. Jiang (Beijing Key Laboratory on Drug-Resistant Tuberculosis Research, Beijing Tuberculosis and Thoracic Tumor Research Institute) for help with the VNTR analysis, and Dr. Joy Fleming for editing the English of the manuscript.

Ethical approval

The protocols applied in this study were approved by the Beijing Tuberculosis and Thoracic Tumour Research Institute/Beijing Chest Hospital, Capital Medical University, and Beijing Research Institute for Tuberculosis Control. Patients were included after they signing an informed consent form. All experiments were performed in the Department of Bacteriology and Immunology of the Beijing Tuberculosis and Thoracic Tumour Research Institute.

Author contributions

YL and XXZ performed the data analysis; YL, CYL designed the study and drafted the manuscript; XXZ, JJY, CL, QX and CY performed the experiments; YL approved and revised the manuscript. All authors have read and approved the final manuscript.

Disclosure statement

The authors have no conflicts of interest.

Availability of data and materials

All data generated or analysed during this study are included in this published article (and its supplementary information files).

Additional information

Funding

This work was supported by the Capital’s Funds for Health Improvement and Research (Grant No. 2018-1-1041 and No. 2020-2-1042); and the National Key Programme of Mega Infectious Disease (Grant No. 2018ZX10301407-006). The sponsor had no role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript.