Biology subjects

Forson, A.

Publications and source records attributed to Forson, A..

3 recordsLinked to original sources

bioRxiv2018

Molecular epidemiology and whole genome sequencing analysis of clinical Mycobacterium bovis from Ghana

BackgroundBovine tuberculosis (bTB) caused by Mycobacterium bovis is a re-emerging problem in both livestock and humans. The association of some M. bovis strains with hyper-virulence, MDR-TB and disseminated disease makes it imperative to understand the biology of the pathogen.\n\nMethodsMycobacterium bovis (15) among 1755 M. tuberculosis complex (MTBC) isolated between 2012 and 2014 were characterized and analyzed for associated patient demography and other risk factors. Five of the M. bovis were whole-genome sequenced and comparatively analyzed against a global collection of published M. bovis genomes.\n\nResultsMycobacterium bovis was isolated from 3/560(0.5%) females and 12/1195(1.0%) males with pulmonary TB. The average age of M. bovis infected cases was 46.8 years (7-72years). TB patients from the Northern region of Ghana (1.9%;4/212) had a higher rate of infection with M. bovis (OR=2.7,p=0.0968) compared to those from the Greater Accra region (0.7%;11/1543). Among TB patients with available HIV status, the odds of isolating M. bovis from HIV patients (2/119) was 3.3 higher relative to non-HIV patients (4/774). Direct contact with livestock or their unpasteurized products was significantly associated with bTB (p<0.0001,OR=124.4,95% CI=30.1-508.3). Two (13.3%) of the M. bovis isolates were INH resistant due to the S315T mutation in katG whereas one (6.7%) was RIF resistant with Q432P and I1491S mutations in rpoB. M. bovis from Ghana resolved as mono-phyletic branch among mostly M. bovis from Africa irrespective of the host and were closest to the root of the global M. bovis phylogeny. M. bovis-specific amino acid mutations were detected among MTBC core genes such as mce1A, mmpL1, pks6, phoT, pstB, glgP and Rv2955c. Additional mutations P6T in chaA, G187E in mgtC, T35A in Rv1979c, S387A in narK1, L400F in fas and A563T in eccA1 were restricted to the 5 clinical M. bovis from Ghana.\n\nConclusionOur data indicate potential zoonotic transmission of bTB in Ghana and hence calls for intensified public education on bTB, especially among risk groups.

microbiology↗

bioRxiv2017

Reduced transmission of Mycobacterium africanum compared to Mycobacterium tuberculosis in urban West Africa

BackgroundUnderstanding transmission dynamics is useful for tuberculosis (TB) control. We conducted a population-based molecular epidemiological study to understand TB transmission in Ghana.\n\nMethodsMycobacterium tuberculosis complex (MTBC) isolates obtained from prospectively-sampled pulmonary TB patients between July, 2012 and December, 2015 were confirmed as MTBC using IS6110 PCR. MTBC lineages were identified by large sequence polymorphism and single nucleotide polymorphism assays and further characterized using spoligotyping and standard 15-loci MIRU-VNTR typing. We used the n-1 method to estimate recent TB transmission and identified associated risk factors using logistic regression analysis.\n\nFindingsOut of 2,309 MTBC isolates, we identified 1,082 (46{middle dot}9%) single cases with 1,227 (53{middle dot}1%) isolates belonging to one of 276 clustered cases (clustering range; 2-35). Recent TB transmission rate was estimated to be 41{middle dot}2%. While we see no significant difference in the recent transmission rates between lineages of Mycobacterium africanum (lineage-5 (31{middle dot}8%); lineage-6 (24{middle dot}7%), p=0{middle dot}118), we found that lineage-4 belonging to the M. tuberculosis transmitted significantly higher (44{middle dot}9%, p<0{middle dot}001). Finally, apart from age being significantly associated with recent TB transmission (p=0{middle dot}007), we additionally identified a significant departure in the male/female ratio among very large clustered cases compared to the general TB patient population (3:1 vs. 2:1, p=0{middle dot}022).\n\nInterpretationsOur findings indicate high recent TB transmission suggesting occurrences of unsuspected outbreaks. The observed reduced transmission rate of M. africanum suggests other factor(s) may be responsible for its continuous presence in West Africa.\n\nFundingWellcome Trust Intermediate Fellowship Grant 097134/Z/11/Z to Dorothy Yeboah-Manu.

epidemiology↗

bioRxiv2017

Comparative genomics of Mycobacterium africanum Lineage 5 and Lineage 6 from Ghana suggests different ecological niches

Mycobacterium africanum (Maf) causes up to half of human tuberculosis in West Africa, but little is known on this pathogen. We compared the genomes of 253 Maf clinical isolates from Ghana, including both L5 and L6. We found that the genomic diversity of L6 was higher than in L5, and the selection pressures differed between both groups. Regulatory proteins appeared to evolve neutrally in L5 but under purifying selection in L6. Conversely, human T cell epitopes were under purifying selection in L5, but under positive selection in L6. Although only 10% of the T cell epitopes were variable, mutations were mostly lineage-specific. Our findings indicate that Maf L5 and L6 are genomically distinct, possibly reflecting different ecological niches.

genomics↗