Discordance Between Fluoroquinolone Resistance Results on Xpert MTB/XDR Panel, Second-line Line Probe Assay and Phenotypic Drug Sensitivity Testing- How to Interpret?
Year: 2025
Type: article
Abstract: clinical problem:A 10-year-old boy presented in February 2024 with fever for 4 months.His older sister had a past history of pulmonary multidrug-resistant tuberculosis (MDR-TB), microbiologically diagnosed 5 years back and who completed treatment after having received secondline antitubercular therapy (ATT) for 2 years.On presentation, his weight was 24 kg (10 th -25 th percentile according to Indian Academy of Pediatrics (IAP) charts) and height was 133.5 cm (25 th -50 th percentile according to IAP charts).General and systemic examinations were normal.Chest X-ray performed at another centre was suggestive of mediastinal lymphadenopathy.High-resolution computerized tomography thorax showed multiple enlarged pre-and paratracheal, pre-and subcarinal and hilar lymph nodes, of which the largest measured 2.6 x 1.5 cm.Few mediastinal lymph nodes showed calcification and multiple discrete nodules were also visualized in the left lower lobe.Bronchoscopy showed no endobronchial involvement.Urine examination found 6-8 pus cells/high power field (HPF), 50-60 erythrocytes/HPF.Abdominal ultrasound was normal.Mediastinal lymph node biopsy Xpert MTB/Rif assay detected medium load rifampicinresistant Mycobacterium tuberculosis (MTB) complex.Xpert MTB/XDR performed on the same sample revealed resistance to isoniazid and kanamycin.Other investigations of the patient are shown in Table 1.He was initially diagnosed with pulmonary and mediastinal lymph node MDR-TB and was started on steroids and a shorter oral second-line ATT regimen consisting of high-dose isoniazid, pyrazinamide, ethambutol, ethionamide, bedaquiline, moxifloxacin and clofazimine.Histopathological examination of the mediastinal lymph node showed granulomatous inflammation with Langhans giant cells, tissue first-line line probe assay (LPA) showed resistance to isoniazid, rifampicin and second-line LPA showed resistance to fluoroquinolones.The mycobacterium growth indicator
Source: Pediatric Oncall
Authors: Dhruv Gandhi, Ira Shah
Institution: Bai Jerbai Wadia Hospital for Children
Language: English
Subfield: Infectious Diseases
Field: Medicine
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W4407276031