Radiological presentation of pulmonary tuberculosis infected by the W-Beijing Mycobacterium tuberculosis strain

SETTING: The W-Beijing strain of Mycobacterium tuberculosis is distributed globally, and is associated with high drug resistance rates in some areas. The effect of the W-Beijing strain on radiological features of pulmonary tuberculosis (PTB) remains unclear.OBJECTIVE: To compare the chest radiological presentation of PTB in patients infected with W-Beijing with that of patients infected with non-W-Beijing strains, and to explore factors affecting radiological patterns.DESIGN: Culture-proven PTB patients without previous anti-tuberculosis treatment were enrolled retrospectively. Chest radiographs were independently reviewed by two qualified chest physicians, and radiological presentation was classified into characteristic and unusual patterns.RESULTS: Of 233 patients studied, 123 (52.8%) were infected with the W-Beijing strain. Characteristic radiological patterns (91.1% vs. 76.4%, P = 0.002) and fibronodular lesions without cavity (57.7% vs. 43.6%, P = 0.032) were more common, while miliary lesions (0.0% vs. 3.8%, P = 0.048) were less frequent, in the W-Beijing group. After stepwise logistic regression analysis, the W-Beijing strain (P = 0.006) was found to be an independent factor for the characteristic radiological pattern for PTB.CONCLUSION: The characteristic radiological pattern for PTB was more common in patients infected with the W-Beijing strain. M. tuberculosis genotyping was an independent factor affecting the radiological presentation of pulmonary TB.