Table 2_Deciphering the population dynamics and drug-resistance characteristics of extrapulmonary tuberculosis: genomic and clinical insights from a Chinese hospital.xlsx

IntroductionExtrapulmonary tuberculosis (EPTB) is characterized by atypical clinical symptoms, difficult diagnosis, and high mortality, so it is very important to know the prevalence and drug resistance (DR) status.
MethodsThis study analyzed 427 isolates of EPTB from a Chinese hospital. Drug susceptibility testing for widely used anti-TB drugs was performed. All isolates were subjected to whole-genome sequencing (WGS) to explore the molecular characteristics of resistance and to perform phylogenetic analysis. Clinical characteristics and DR patterns associated with Mycobacterium tuberculosis (MTB) lineages were evaluated using chi-square analysis, and associations with DR-EPTB were assessed using multinomial logistic regression.
ResultsThe number of EPTB strains exhibited a general upward trend, and most EPTB cases in this study were accompanied by PTB. The predominant types were tuberculosis of urinary system (29.98%), tuberculous meningitis (23.65%), and lymph node tuberculosis (22.72%). Quadratic regression revealed a decline in urinary system cases and an increase in lymph node cases. Lineage 2 accounted for 83.60% of isolates and was significantly associated with isoniazid (INH) and streptomycin (STR) resistance. Overall resistance rates were 13.58% for INH and 7.73% for rifampicin (RIF). Male sex was associated with higher DR risk (aOR = 1.63, p = 0.046). Common resistance mutations included katG Ser315Thr, rpoB Ser450Leu, and gyrA mutations. The clustering rate was 19.67%, indicating limited recent transmission.
DiscussionThe predominance of lineage 2 and high rates of anti-tuberculosis drug resistance indicate that EPTB remains a clinically and epidemiologically significant problem.

引言：肺外结核（Extrapulmonary tuberculosis, EPTB）以临床症状不典型、诊断难度大、病死率高为主要特征，明确其流行现状与耐药（drug resistance, DR）情况具有重要临床意义。
方法：本研究纳入国内某医院分离的427株肺外结核分枝杆菌临床分离株。对临床常用抗结核药物开展药物敏感性试验，对所有分离株进行全基因组测序（whole-genome sequencing, WGS）以解析耐药分子特征并开展系统发育分析。采用卡方检验评估结核分枝杆菌（Mycobacterium tuberculosis, MTB）谱系与临床特征、耐药表型的关联，同时采用多分类logistic回归分析探究其与耐药性肺外结核（Drug Resistance-Extrapulmonary Tuberculosis, DR-EPTB）的相关性。
结果：本研究中肺外结核分枝杆菌分离株数量整体呈上升趋势，且多数病例合并肺结核（Pulmonary Tuberculosis, PTB）。最常见的感染类型为泌尿系统结核（29.98%）、结核性脑膜炎（23.65%）以及淋巴结结核（22.72%）。二次回归分析显示，泌尿系统结核病例数呈下降趋势，而淋巴结结核病例数则逐步上升。谱系2（Lineage 2）占分离株的83.60%，且与异烟肼（isoniazid, INH）、链霉素（streptomycin, STR）耐药显著相关。整体耐药率分别为异烟肼13.58%、利福平（rifampicin, RIF）7.73%。男性与更高的耐药风险相关（校正比值比aOR=1.63，p=0.046）。常见耐药突变包括katG Ser315Thr、rpoB Ser450Leu以及gyrA基因突变。菌株聚集率为19.67%，提示近期传播范围有限。
讨论：谱系2（Lineage 2）的优势流行以及较高的抗结核药物耐药率提示，肺外结核仍是临床与流行病学层面亟需重视的公共卫生问题。