Molecular detection and characterization of multidrugresistant Mycobacterium tuberculosis in a referral health facility in Akwa Ibom State, Nigeria

Abstract

The dramatic upsurge in cases of drug-resistant Mycobacterium tuberculosis infections in recent years has raised serious therapeutic concerns. This study was carried out to molecularly detect and characterise drug-resistant Mycobacterium tuberculosis (MTB) isolates in patients from TB/Leprosy referral centre at Etinan in Akwa Ibom State. A cross-sectional study for a period of 12 months involving 220 sputum-producing patients with suspected cases of pulmonary tuberculosis (PTB) was carried out. Samples were collected and processed following standard procedures and assayed for PTB infection and drug resistance simultaneously using GeneXpert MTB/RIF and Xpert MTB/XDR, while anti-PTB drug susceptibility testing, molecular detection and characterisation of resistant genes (katG, inhA, embB and gyrA) were carried out using GeneXpert assays, polymerase chain reaction (PCR), and phylogenetic sequencing analysis. The results revealed 18.6% and 29.1% prevalence of PTB using GeneXpert MTB/RIF and TB-LAMP, respectively (p=0.01). The rates of PTB infection
were significantly associated with the diagnostic assay used. The prevalence rate of MDR-TB and rifampicin-resistant-TB (RR-TB) was 29.3% and 3.2%, respectively. The PCR results showed 75%, 25%, 37.5% and 62.5% of selected anti-PTB drug-resistant isolates, respectively, harbouring embB, inhA, gyrA and katG genes. Sequencing and phylogenetic results revealed the dominant MTB strain such as Mycobacterium tuberculosis complex NO157, Mycobacterium tuberculosis strain 5521, Mycobacterium tuberculosis H37Rv and Mycobacterium tuberculosis strain 02-R1179, circulating among patients in the facility. The study findings revealed the prevalence of PTB, MDR-TB, and molecular epidemiology of the circulating strains in the facility. Integrated surveillance and control strategies are needed to curb potential spillover and dissemination of multidrug-resistant MTB strains.