Identification of Mycobacterium avium KatG protein (MAV_2753) as a possible serodiagnostic marker for MAC disease

Abstract

Disseminated Mycobacterium avium complex (MAC) infection is a severe complication of advanced HIV disease. 1 Corti M. Palmero D. Mycobacterium avium complex infection in HIV/AIDS patients. Expert Rev Anti Infect Ther. 2008; 6: 351-363 Crossref PubMed Scopus (55) Google Scholar The poor prognosis of disseminated MAC disease 2 Collins T.M. Lisby G. Moser C. Chicks D. Results of multiple diagnostic test for Mycobacterium avium subsp. paratuberculosis in patients with inflammatory bowel disease and in controls. J Clin Microbiol. 2000; 38: 4373-4381 PubMed Google Scholar makes its timely diagnosis extremely important to initiate the appropriate therapy. However, the various diagnostic methods, whether conventional (phenotypic identification of culture and biochemical testing) or new generation (nucleic acid based approaches), so far developed for the detection and diagnosis of MAC disease, have their own limitations and thus prove unsatisfactory. 3 Arnold Jr., L.J. Hammond P.W. Wiese W.A. Nelson N.C. Assay formats involving acridinium-ester-labeled DNA probes. Clin Chem. 1989; 35: 1588-1594 PubMed Google Scholar , 4 Lefmann M. Schweickert B. Buchholz P. Gobel U.B. Ulrichs T. Seiler P. et al. Evaluation of peptide nucleic acid-fluorescence in situ hybridization for identification of clinically relevant mycobacteria in clinical specimens and tissue sections. J Clin Microbiol. 2006; 44: 3760-3767 Crossref PubMed Scopus (63) Google Scholar , 5 Steadham E.J. Reliable urease test for identification of mycobacteria. J Clin Microbiol. 1979; 10: 134-137 PubMed Google Scholar Therefore, a rapid and simple test for the identification of MAC bacteremia is the need of hour. In this regard, serodiagnosis on the basis of immunodominant antigens secreted by actively growing bacilli in culture filtrate could be an attractive strategy being an easy to perform, cost effective, rapid 6 Kitada S. Kobayashi K. Ichiyama S. Takakura S. Sakatani M. Suzuki K. et al. Serodiagnosis of Mycobacterium avium-complex pulmonary disease using an enzyme immunoassay kit. Am J Respir Crit Care Med. 2008; 177: 793-797 Crossref PubMed Scopus (90) Google Scholar and highly sensitive technique capable of detecting mycobacterial antigens at a concentration of 10−9/ml. 7 Kadival G.V. Samuel A.M. Virdi B.S. Kale R.N. Ganatara R.D. Radioimmunoassay of tuberculosis antigen. Indian J Med Res. 1982; 75: 765-770 Google Scholar The present study carried out with a goal to identify M. avium secretory protein(s) of diagnostic significance demonstrated that the KatG protein in M. avium culture filtrate could be used as a possible serodiagnostic marker for disseminated MAC disease in AIDS patients.