The Prevalence and Profile of Mycobacterial Infections in Liver Diseases from Tertiary Care Hepatobiliary Centre
Dr. Vikas Khillan,
Additional Professor, Department of Clinical Microbiology, Institute of Liver and Biliary Sciences, Delhi-110070, India.
Introduction: There is paucity of data regarding mycobacterial infections in liver diseases. Guidelines do not exist for diagnosis, monitoring of patients and modification of the treatment.
Aim: Our aim was to elucidate demographic characteristics, profile of mycobacterial infection and comparison of diagnostic methods in liver diseases.
Materials and Methods: We studied liver disease patients from January 2012 to December 2016, screened for Tuberculosis (TB) if having fever, cough for >2 weeks, haemoptysis, unexplained weight loss, increasing ascites, unresponsive to diuretics, unexplained bowel symptoms, radiological lesions and past or family history of TB. TB diagnosed if there is: (i) histological caseating granulomas; (ii) smear Acid Fast Bacilli; (AFB) positivity; (iii) growth on Mycobacterial Growth Indicator Tube (MGIT) culture; or (iv) positive quantitative polymerase chain reaction for Mycobacterium tuberculosis (MTB qPCR). Mycobacteria other than tuberculosis (MOTT) were identified by negative MPT64 assay.
Results: Of the 118/816 positive samples, 31/260 (11.92%) were pulmonary and 87/556 (15.65%) were extra-pulmonary TB (EPTB). There was a male preponderance (66.1%), median age 53 years in pulmonary and 37 years in EPTB. Thirty two samples (27.11%) were smear positive, low in EPTB 13/87 (14.9%) as compared to 19/31 (61.2%) pulmonary. MGIT was positive in 108/118 (91.52%) and 97/118 (82.2%) were MTB qPCR positive. MTB was isolated from all pulmonary samples and 72/87 (82.75%) of EPTB. MOTT was identified in 15/118(12.71%). Sensitivity and specificity of MTB qPCR was 90.3% and 100% respectively in pulmonary and 76.6% and 97.9% respectively in EPTB.
Conclusion: There is predominance of smear negative, EPTB and MOTT in liver diseases. MGIT culture and TB PCR have additive advantage over either test alone. MOTT should be ruled out in all cases as treatment varies. High index of suspicion and good screening methods are needed to identify TB and MOTT owing to similar presentation and anti-tubercular drug toxicity issues.