Case Report: Single-cell metabolic labeling probe for diagnosing renal tuberculosis.

Extrapulmonary tuberculosis (EPTB) is characterized by low bacterial load and complex matrix in lesion samples. Therefore, current tuberculosis (TB) diagnostic methods often lose sensitivity to detect Mycobacterium tuberculosis (Mtb), leading to missed diagnosis and delayed treatment. Herein, we presented a single-cell metabolic labeling probe for tuberculosis (SCMLP-TB), which exhibited supporting investigative evidence for diagnosis of renal TB case, and enabled investigative monitoring of therapeutic efficacy of anti-TB regimens. A 51-year-old patient presented with fever, generalized weakness and muscle soreness on admission. Chest computed tomography (CT) revealed calcified mediastinal lymph nodes, and relevant renal function indicators were abnormal. Conventional TB diagnostic methods, including Xpert MTB/RIF, TB-DNA testing, and culture, yielded negative results using sputum, blood, and urine samples. Notably, SCMLP-TB assay detected Mtb in urine samples, suspecting renal TB. SCMLP-TB assay further detected gradually decreased bacterial viability along with anti-TB treatment (isoniazid, rifapentine, ethambutol, and pyrazinamide), revealing the efficacy of current regimen. The patient's symptom resolution and anemia/renal function improvement provided auxiliary evidence of antimicrobial efficacy. Ultimately, SCMLP-TB showed great potential for non-invasive, sensitive detection of suspected renal TB, and enabled investigative monitoring of the therapeutic efficacy.