Genomic epidemiology of the Mycobacterium tuberculosis complex in Fiji reveals community transmission and human Mycobacterium bovis infection.

INTRODUCTION

Tuberculosis (TB) remains a major public health concern in Fiji, but genomic data on the circulating Mycobacterium tuberculosis complex (MTBC) are limited.

METHODS

We analysed 65 MTBC isolates collected during 2019-2022 using whole-genome sequencing to characterize lineage distribution, drug resistance, and transmission patterns.

RESULTS

Of the isolates, 62 (95.4%) were Mycobacterium tuberculosis and 3 (4.6%) were Mycobacterium bovis. Lineage 4 was the most common (29/62, 46.8%). Genomic analysis identified 12 transmission clusters, with epidemiological links involving households, schools, and neighbouring communities. Most MTBC isolates (57/65, 87.7%) were susceptible to first-line anti-TB drugs; however, 8 (12.3%) carried resistance-associated mutations in katG, rpoB, rrs, or pncA. Treatment outcomes indicated that 20 (30.8%) patients were lost to follow-up.

DISCUSSION: Detection of M. bovis suggests possible zoonotic transmission and highlights limitations of routine diagnostics. These findings indicate diverse MTBC lineages and localized transmission networks, supporting integration of genomic surveillance into TB control efforts in Fiji.