High rate of reinfection and possible transmission of Mycobacterium avium complex in Northeast Thailand
Wicharajit Boonjetsadaruhk,
Orawee Kaewprasert,
Arnone Nithichanon,
Pimjai Ananta,
Prajuab Chaimanee,
Kanin Salao,
Wisitsak Phoksawat,
Marut Laohaviroj,
Auttawit Sirichoat,
Yang Fong,
Suwin Wongwajana,
Wises Namwat,
Viraphong Lulitanond,
Ploenchan Chetchotisakd,
Kiatichai Faksri
Affiliations
Wicharajit Boonjetsadaruhk
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Orawee Kaewprasert
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Arnone Nithichanon
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Pimjai Ananta
Clinical Microbiology Unit, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Prajuab Chaimanee
Clinical Microbiology Unit, Srinagarind Hospital, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Kanin Salao
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Wisitsak Phoksawat
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Marut Laohaviroj
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Auttawit Sirichoat
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Yang Fong
Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand; Massey University, Turitea Campus, Tennent Drive, Palmerston North, New Zealand
Suwin Wongwajana
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Wises Namwat
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Viraphong Lulitanond
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand
Ploenchan Chetchotisakd
Department of Medicine, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand
Kiatichai Faksri
Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen, Thailand; Research and Diagnostic Center for Emerging Infectious Diseases, Khon Kaen University, Khon Kaen, Thailand; Corresponding author at: Department of Microbiology, Faculty of Medicine, Khon Kaen University, Khon Kaen 40002, Thailand.
The Mycobacterium avium complex (MAC) includes two main species of non-tuberculous mycobacteria (NTM), M. avium and Mycobacterium intracellulare. These can cause serious disease, especially in immunocompromised patients. Little information is available concerning genetic diversity of NTM. We used multilocus sequence typing (MLST) based on a highly discriminative gene set to analyze MAC serially isolated from patients to determine the rate of MAC reinfection. Genomic DNA was sequenced from 49 MAC isolates (15 cases comprised of 11 true infections and 4 instances of colonization). More than half of the MAC isolates tested were found to be multidrug resistant. The discriminatory power was assessed of 24 house-keeping genes (fusA, atpD, pheT, glnA, topA, secA, argH, glpK, murC, cya, pta, rrl, rrs, hsp65, rpoB, 16S-23S rRNA ITS, recF, lipT, pepB, gnd, aspB, groEL, sodA and est) previously used for genotyping of MAC and other NTM. Seven genes (fusA, secA, rpoB, hsp65, 16S rRNA, 23S rRNA, 16S-23S rRNA ITS) had a discriminatory power index higher than 0.9 and were included in the optimized set that we used. This set was significantly better for genotyping and diagnosis of MAC than previously used 4-gene, 5-gene and 9-gene sets. MLST using our 7-gene set indicated that the rate of reinfection was 54.55% (6/11 cases). Persistent infections (n = 5 cases, 45.45%) were found. A changing of clone in the same patient was found in 1/4 (25%) of the colonization cases. Two small clusters of possible MAC transmission between humans were found. Our study demonstrated that the high frequency of apparent treatment failure of MAC might be artefactual, as a consequence of a high rate of MAC reinfection in Thai population. Our useful highly discriminative gene set for MAC species and clonal strain analysis could be further applied for the diagnosis and patient management.
