Gabon carries a high burden of both tuberculosis (TB) and smoking. This study examines the disease characteristics of smoking pulmonary TB patients in Lambaréné. We interviewed adult pulmonary TB patients in Lambaréné, between March 2016 and April 2019. Clinical and biological patient characteristics were collected. Bivariate and logistic regression analyses were performed to assess factors associated with smoking. The mean age of patients included was 31 years (±13). The proportion of smokers in our study was 30% (89/295). Smoking was significantly associated with patient-related diagnostic delay (adjusted odds ratio [AOR] = 8.18; 95% CI = 3.67–19.56), a higher number of pulmonary TB signs and symptoms (AOR = 2.74; 95% CI = 1.18–6.73), and a higher sputum mycobacterial load (AOR = 3.18; 95% CI = 1.33–8.11). The prevalence of smoking among TB patients is high, and leading to aggravated disease as compared with controls. Our study findings suggest that smoking patients should be regularly screened for TB, to reduce diagnostic delay and TB transmission within community. Smoking cessation activities should be included in the national TB control program in Gabon.

Since May 2016, WHO recommended a 9–12 month short-treatment regimen for multidrug-resistant tuberculosis (MDR-TB) treatment known as the ‘Bangladesh Regimen’. However, limited data exist on the appropriateness thereof, and its implementation in low- and middle-income countries (LMIC). We report here on the pilot phase of the evaluation of the Bangladesh regimen in Gabon, prior to its endorsement by the WHO.

This study aimed to investigate genotypic characteristics and drug resistance profiles of Mycobacterium tuberculosis complex (Mtbc) strains isolated from patients with suspected tuberculosis (TB) in Gabon. We performed whole genome sequencing of 430 Mtbc strains cultured between 2012 and 2022. Phylogenetic strain classification, genomic resistance prediction, and cluster analysis were also performed. Strains from four major Mtbc lineages, L4 (n = 372; 65%), L5 (n = 46; 11%), L2 (n = 6; 1,4%), and L6 (n = 3; 0,7%), were observed. Interestingly, more than 10% of the strains were represented by Mycobacterium africanum strains (L5 and L6), with L4 strains being dominant. The subclassification of L4 strains showed that L4.6.2.2 (Cameroon, n = 116) was the most prevalent. The proportion of resistance (any resistance to first-line TB drugs) was 30%, with 12% (n = 52) being at least multidrug-resistant (MDR) and six showing additional fluoroquinolone resistance. The overall cluster rate was 64% in non-MDR and MDR Mtbc strains. Although most Mtbc infections are caused by L4 M. tuberculosis strains, M. africanum strains also contribute to TB epidemiology in Gabon. The MDR epidemic is mainly driven by one dominant L4 Haarlem outbreak clone that has been spreading for approximately a century in the country.

Non-tuberculous mycobacteria (NTM) are a group of bacteria that cause rare lung infections and are increasingly recognized as causative agents of opportunistic and device-associated infections in humans. In Gabon, there is a lack of data on NTM species identification and drug susceptibility. The aim of this study was to identify the frequency of NTM species and their genotypic susceptibility pattern to commonly used antibiotics for NTM infections in Gabon. A cross-sectional study was conducted at the CERMEL TB laboratory from January 2020 to December 2022, NTM subspecies identification and drug susceptibility testing to macrolides and aminoglycosides were performed using the genotype NTM-DR kit. The study found that out of 524 culture-positive specimens, 146 (28%) were NTM, with the predominant group being Mycobacterium avium complex (MAC) and Mycobacterium abscessus complex (MABC). All MAC isolates were fully susceptible to macrolides and aminoglycosides, while five MABC isolates carried mutations indicative of reduced susceptibility to macrolide and aminoglycoside drugs. These findings suggest that clinicians may use macrolides and aminoglycosides to manage NTM infections caused by MAC, but further investigation is required to determine MABC drug susceptibility.

Tuberculosis (TB) remains a major public health challenge, particularly in sub-Saharan Africa, where the emergence of drug-resistant MTB undermines current control efforts. This study aimed to characterize genetic mutations associated with resistance to first- and second-line injectable drugs in MTB isolates from pulmonary TB patients in the Republic of Congo. A total of 45 culture-positive MTB isolates collected between 2018 and 2019 were analyzed using targeted next-generation sequencing on the MinION device. Resistance-associated genes, including rpoB, katG, embB, gyrA, and rrs, were examined. Overall, 22/45 isolates (48%) harbored at least one mutation associated with drug resistance. Among resistant isolates, rifampicin resistance was detected in 15 of 22 (68.2%), predominantly associated with mutations in the rpoB rifampicin resistance–determining region, including p.Ser531Leu, p.Asp516Val, and p.His526Tyr.Ethambutol resistance was observed in 11 of 22 isolates (50.0%) and was mainly associated with the embB p.Met306Val mutation. Isoniazid resistance was detected in 9 of 22 isolates (40.9%), primarily associated with the KatG p.Ser315Thr mutation. Fluoroquinolone resistance was identified in 2 of 22 isolates (9.1%), mainly associated with gyrA p.Ala90Val and p.Asp94Gly mutations. Resistance to second-line injectable drugs was detected in 1 of 22 isolates (4.5%) and was associated with the rrs p.Ala1401Gly mutation. These findings underscore the need to enhance molecular surveillance and strengthen treatment protocols for drug-resistant TB in the Republic of Congo to effectively combat this evolving health crisis.