Division of Bioresources, Hokkaido University International Institute for Zoonosis Control, Sapporo, Hokkaido, Japan; Zambia National Public Health Institute, Ministry of Health, Lusaka, Zambia.
Division of Bioresources, Hokkaido University International Institute for Zoonosis Control, Sapporo, Hokkaido, Japan; University Teaching Hospital, Ministry of Health, Lusaka, Zambia.
Int J Infect Dis. 2022 Jan;114:142-150. doi: 10.1016/j.ijid.2021.10.044. Epub 2021 Oct 27.
Zambia is among the 30 high tuberculosis burden countries in the world. Despite increasing reports of multidrug-resistant tuberculosis (MDR-TB) in routine surveillance, information on the transmission of MDR Mycobacterium tuberculosis strains is largely unknown. This study elucidated the genetic diversity and transmission of MDR M. tuberculosis strains in Lusaka, Zambia.
Eighty-five MDR M. tuberculosis samples collected from 2013 to 2017 at the University Teaching Hospital were used. Drug-resistance associated gene sequencing, spoligotyping, 24-loci mycobacterial interspersed repetitive units-variable number of tandem repeats (MIRU-VNTR), and multiplex PCR for RD-Rio sub-lineage identification were applied.
The identified clades were LAM (48%), CAS (29%), T (14%), X (6%) and Harlem (2%). Strains belonging to SITs 21/CAS1-Kili and 20/LAM1 formed the largest clonal complexes. Combined spoligotyping and 24 loci-MIRU-VNTR revealed 47 genotypic patterns with a clustering rate of 63%. Ninety-five percent of LAM strains belonged to the RD-Rio sub-lineage.
The high clustering rate suggested that a large proportion of MDR-TB was due to recent transmission rather than the independent acquisition of MDR. This spread was attributed to clonal expansion of SIT21/CAS1-Kili and SIT20/LAM1 strains. Therefore, TB control programs recommending genotyping coupled with conventional epidemiological methods can guide measures for stopping the spread of MDR-TB.
赞比亚是世界上 30 个结核病高负担国家之一。尽管常规监测中不断有报道称耐多药结核病（MDR-TB）病例增加，但关于 MDR 结核分枝杆菌菌株传播的信息知之甚少。本研究阐明了赞比亚卢萨卡地区 MDR 结核分枝杆菌菌株的遗传多样性和传播。
从 2013 年至 2017 年，在教学医院收集了 85 株 MDR 结核分枝杆菌样本。应用耐药相关基因测序、 spoligotyping 、24 位结核分枝杆菌间隔重复单位-可变数串联重复（MIRU-VNTR）和 RD-Rio 亚谱系鉴定的多重 PCR 。
确定的分枝杆菌属包括 LAM（48%）、CAS（29%）、T（14%）、X（6%）和 Harlem（2%）。属于 SITs21/CAS1-Kili 和 20/LAM1 的菌株形成了最大的克隆复合体。 spoligotyping 和 24 位 MIRU-VNTR 联合分析显示，47 种基因型模式的聚类率为 63%。95%的 LAM 菌株属于 RD-Rio 亚谱系。
高聚类率表明，很大一部分 MDR-TB 是由于近期传播而不是独立获得 MDR 引起的。这种传播归因于 SIT21/CAS1-Kili 和 SIT20/LAM1 菌株的克隆扩张。因此，推荐基因分型与传统流行病学方法相结合的结核病控制计划可以指导停止 MDR-TB 传播的措施。
