DST/NRF Centre of Excellence for Biomedical TB Research, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand and the National Health Laboratory Service, Johannesburg 2000, South Africa.
Centre for Tuberculosis, National Institute for Communicable Diseases and National Health Laboratory Service, Johannesburg, 2000, South Africa.
Pathog Dis. 2017 Apr 1;75(3). doi: 10.1093/femspd/ftx020.
Tuberculosis (TB) disease can be characterized by genotypic and phenotypic complexity in Mycobacterium tuberculosis bacilli within a single patient. This microbiological heterogeneity has become an area of intense study due its perceived importance in drug tolerance, drug resistance and as a surrogate measure of transmission rates. This review presents a descriptive analysis of research describing the prevalence of mixed-strain TB infections in geographically distinct locations. Despite significant variation in disease burden and a rampant human immunodeficiency virus (HIV)-TB co-epidemic, there was no difference in the prevalence range of mixed infections reported in African countries when compared to the rest of the world. The occurrence of recurrent TB was associated with a higher prevalence of mixed-strain infections, but this difference was not reported as statistically significant. These interpretations were limited by differences in the design and overall size of the studies assessed. Factors such as sputum quality, culture media, number of repeated culture steps, molecular typing methods and HIV-infection status can affect the detection of mixed-strain infection. It is recommended that future clinical studies should focus on settings with varying TB burdens, with a common sample processing protocol to gain further insight into these phenomena and develop novel transmission blocking strategies.
结核病（TB）疾病可表现为同一患者体内结核分枝杆菌的基因型和表型复杂性。由于其在药物耐受性、药物耐药性以及作为传播率替代指标方面的重要性，这种微生物异质性已成为研究的热点领域。本综述对描述不同地理位置混合菌株结核病感染流行情况的研究进行了描述性分析。尽管疾病负担存在显著差异，且人类免疫缺陷病毒（HIV）-结核病共同流行猖獗，但与世界其他地区相比，非洲国家报告的混合感染流行率并无差异。复发性结核病的发生与混合菌株感染的更高流行率相关，但这一差异未被报告为具有统计学意义。这些解释受到评估研究的设计和总体规模差异的限制。痰液质量、培养介质、重复培养步骤的数量、分子分型方法和 HIV 感染状态等因素可能会影响混合菌株感染的检测。建议未来的临床研究应侧重于结核病负担不同的环境，并采用通用的样本处理方案，以深入了解这些现象并开发新的传播阻断策略。
