An emergence of Mycobacterium abscessus in blood cultures of Thai patients

Abstract

© 2020 Universiti Sains Malaysia. Aims: Tuberculosis and other mycobacterial infections occur worldwide especially in patients with immunodeficiency. Typically, an empirical treatment for disseminated disease is required for initial therapy due to slow growing nature of most mycobacterial species. Therefore, species distribution and average time to positivity of blood culture is crucial. However, such information is limited for blood culture and, therefore, were determined. Methodology and results: The blood culture data using the BACTEC FX system and drugs susceptibility testing (DST) pattern was recovered during 2012-2017 from a large teaching hospital in Bangkok, Thailand. Overall, 7.8% of 4,838 blood and 6.4% of 1,056 bone marrow (BM) samples were positive for mycobacterial growth. Mycobacterium tuberculosis complex (MTBC), M. avium, and M. abscessus, were the most three common species to be isolated from blood (3.8%, 2.1%, and 0.9%, respectively) and BM (2.4%, 2.4%, and 0.9%, respectively). The average time to positivity for MTBC, M. avium, and M. abscessus was 25.7, 16.1, and 3.8 days, respectively. From 209 antimycobacterial susceptibility testing (AST)-available MTBC strains, 6 (2.87%) strains were multi-drugs resistant (MDR-TB). From 35 AST-available M. avium complex (MAC) isolates, 6 (17.14%), 33 (94.29%), and 28 (80%) isolates were resistant to clarithromycin, moxifloxacin, and linezolid, respectively. BM MAC isolates were significantly more resistant to clarithromycin than the blood isolates (44.5% vs 7.69%; p= 0.027). Conclusion, significance and impact of study: In summary, an emergence of M. abscessus and unusually high moxifloxacin and linezolid resistance of MAC isolates were reported in this study. Additional information of this study benefits physicians for anti-mycobacterial drug selection for initial treatment of mycobacteremia while blood and BM culture is pending.