Case presentation
A 32-year-old man was referred to Ghaem Hospital affiliated to Mashhad University of Medical Sciences in February 2019 with symptoms of night sweats, cough, and chest pain with previous pulmonary infectionmycobacterium tuberculosis diagnosis based on positive acid-fast bacilli smear test. The patient was received a standard 6-month regimen including rifampin, isoniazid, ethambutol and pyrazinamide. He had no history of alcohol use and smoking. The patient had a weight loss of 9 kg over one year. The patient worked in a clothing industry that was not exposed to sunlight. An initial test performed on the patient showed severe vitamin D deficiency. A serology test for HIV was negative. The chest X-ray revealed an increase in pleural thickness was seen in the left lung and less strongly in the right lung. Reticular lesions were observed in the field of lungs, specifically, at the top of the lungs (Figure 1A). High-resolution computed tomography (HRCT) revealed bronchiectasis, distractive changes and multiple cysts with collapse in the left upper lobe. Bronchiectasis and cyst formation with tree-in-bud pattern were observed in the right upper lobe and less intensively in the right middle lobe and upper left lower lobe segment and with less intensity in the upper right lobe (Figure 1C). Laboratory findings (table 1) combined with the clinical signs of the patient raised the possibility of Mycobacterium tuberculosis infection (TB). Therefore, direct smear microscopy for acid-fast bacilli (AFB) and mycobacterial culture were performed on the patient’s sputum sample. All three samples obtained from the patient were smear-positive for AFB using Ziehl–Neelsen method. Also, mycobacterial culture of the patient’s samples on Lowenstein-Jensen medium became positive for AFB twenty-two days after inoculation. To identify the grown bacterium, two independent PCR assays were performed on the DNA extracted from the bacterial colonies. One PCR assay had been designed to detect IS6110 , a specific gene target for M. tuberculosiscomplex, in the specimen and the other assay detected rpoB , a mycobacterium genus-specific target. The organism was identified as (NTM) due to obtaining negative and positive results respectively for the former and the latter PCR assays. results were also confirmed by sequencing of the ITS (16S-23S) (accession number MN124505),rpoB (accession number MN158122), and hsp65 (accession number MN158123) genes of M. szulgai . Therefore, treatment with isoniazid (225mg/daily), rifampicin (450mg/daily), ethambutol (825mg/daily), clarithromycin (1000mg/daily), vitamin B6 (10 mg/day) and vitamin D (1000 IU/day) was started. After ten months of treatment, a sputum sample was taken from the patient, smear, and culture tests were negative. Chest pain and dyspnea were resolved and the patient gained 6 kg. Significant improvement was seen in the chest X-ray (Figure 1B). The patient’s serum vitamin D also reached normal.