Biology subjects

Mihret, A.

Publications and source records attributed to Mihret, A..

4 recordsLinked to original sources

bioRxiv2026

Hepatitis C virus genotype homogeneity and lack of major Sofosbuvir resistance-associated substitutions among blood donors in Ethiopia

Hepatitis C virus (HCV) is a hepatotropic virus that causes a spectrum of liver diseases. HCV genetic diversity influences transmission, pathogenesis, prognosis, and response to antiviral therapy. Moreover, resistance associated substitutions (RASs) challenged the existing antiviral treatment. However, data regarding circulating genotypes and RASs are limited in Ethiopia. Therefore, this study aimed to determine HCV genotypes and RASs among apparently healthy blood donors. This study used 97 archived anti-HCV-positive serum samples obtained from apparently healthy blood donors, collected in accordance with national routine blood collection practices. The partial HCV NS5B gene of 45 samples was amplified and sequenced using amplicon-based next-generation sequencing. Genotypes and subgenotypes were determined using NCBI BLAST, Geno2Pheno [hcv], and the Los Alamos HCV database, and a phylogenetic tree as a confirmation. The RASs were determined using Geno2Pheno [hcv]. Of the 97 anti-HCV- positive samples, 45 had detectable HCV RNA, of which 35 yielded high-quality sequences. These strains (n = 35) showed marked homogeneity in NS5B gene sequences: 34 were HCV genotype 4, all subgenotype 4d, and one was HCV genotype 2, subgenotype 2c. Most strains carried D310N, an RAS associated with ribavirin, while no RASs associated with sofosbuvir resistance were detected. There is HCV genotype homogeneity with HCV genotype 4, particularly HCV subgenotype 4d, predominating. No major sofosbuvir RASs were found, but ribavirin RAS D310N was common. Future studies should use broader geographic sampling and whole-genome sequencing to comprehensively characterize RASs, their distributions, clinical significance, and temporal trends, thereby guiding treatment strategies in Ethiopia. ImportanceHepatitis C virus infection remains a major global health concern. Its high genetic diversity influences viral evolution, transmission, and response to antiviral therapy. Despite the significant burden of hepatitis C virus infection in sub-Saharan Africa, molecular data on circulating genotypes, subgenotypes, and resistance associated substitutions remain limited. The significance of our research is in characterizing the genetic diversity and resistance associated substitutions among hepatitis C virus strains circulating in Ethiopia. These findings provide important insights into hepatitis C virus molecular epidemiology and may support genomic surveillance, optimization of treatment strategies, and improved understanding of viral evolution trends and patterns among blood donor populations.

microbiology↗

bioRxiv2020

Population structure and transmission of Mycobacterium bovis in Ethiopia

Bovine tuberculosis (bTB) is endemic in cattle in Ethiopia, a country that hosts the largest national cattle herd in Africa. The intensive dairy sector, most of which is peri-urban, has the highest prevalence of disease. Previous studies in Ethiopia have demonstrated that the main cause is Mycobacterium bovis (M. bovis), which has been investigated using conventional molecular tools including deletion typing, spoligotyping and Mycobacterial interspersed repetitive unit-variable number tandem repeat (MIRU-VNTR). Here we use whole genome sequencing (WGS) to examine the population structure of M. bovis in Ethiopia. A total of 134 M. bovis isolates were sequenced including 128 genomes from 85 mainly dairy cattle and six genomes isolated from humans, originating from 12 study sites across Ethiopia. These genomes provided a good representation of the previously described population structure of M. bovis, based on spoligotyping and demonstrated that the population is dominated by the clonal complexes African 2 (Af2) and European 3 (Eu3). A range of within-host diversity was observed amongst the isolates and evidence was found for both short- and long-distance transmission. Detailed analysis of available genomes from the Eu3 clonal complex combined with previously published genomes revealed two distinct introductions of this clonal complex into Ethiopia between 1950 and 1987, likely from Europe. This work is important to help better understand bTB transmission in cattle in Ethiopia and can potentially inform national strategies for bTB control in Ethiopia and beyond.

genomics↗

bioRxiv2020

Bacterial profiles and their antimicrobial susceptibility pattern of Isolates from inanimate hospital environments at Tikur Anbessa Specialized Teaching Hospital, Addis Ababa, Ethiopia

Microbial contamination of hospital environment plays an important role in the spread of health care-associated infections (HCAIs). This study was conducted to determine bacterial contamination, bacterial profiles and antimicrobial susceptibility pattern of bacterial isolates from environmental surfaces and medical equipment. A cross-sectional study was conducted at Tikur Anbessa Specialized Hospital (TASH) from June to September, 2018. A total of 164 inanimate surfaces located at intensive care units (ICUs) and operation theaters (OTs) were swabbed. All isolates were identified by using routine bacterial culture, Gram staining and a panel of biochemical tests. For each identified bacteria, antibiogram profiles were determined by the Kirby Bauer disk diffusion method according to the guidelines of the Clinical and Laboratory Standards Institute (CLSI). Out of the 164 swabbed samples, 141 (86%) were positive for bacterial growth. The predominant bacteria identified from OTs and ICUs were S. aureus (23% vs 11.5%), Acinetobacter spp (3.8% vs 17.5%) and Coagulase negative Staphylococcus (CONS) (12.6% vs 2.7%) respectively. Linens were the most contaminated materials among items studied at the hospital (14.8%). The proportions of resistance among Gram-positive bacteria (GPB) were high for penicillin (92.8%), cefoxitin (83.5%) and erythromycin (54.1%). However, the most effective antibiotics were clindamycin with only 10.4% and 16.5% resistance rates, respectively. The antimicrobial susceptibility profiles of Gram-negative bacteria (GNB) revealed that the most effective antibiotics were amikacin, ciprofloxacin, and gentamicin with resistance rate of 25%, 37.5%, and 46.3%, respectively. However, the highest resistance was recorded against ampicillin (97.5%), ceftazidime (91.3%), ceftriaxone (91.3%) and aztreonam (90%). The inanimate surfaces near immediate patient environment and commonly touched medical equipment within OTs and ICUs are reservoirs of potential pathogenic bacteria that could predispose critically ill patients to acquire HCAIs. The proportions of antimicrobial resistance profile of the isolates are much higher from studied clean inanimate environments.

microbiology↗

bioRxiv2019

Prevalence of pulmonary tuberculosis among patients presenting with cough of any duration in Addis Ababa, Ethiopia

BackgroundThe current practice in Ethiopia to diagnose tuberculosis is screening patients with cough for at least two weeks. A health facility based study was conducted to estimate the prevalence of smear and culture positive pulmonary TB among patients presenting with cough [≥]2 weeks and <2 weeks in Addis Ababa, Ethiopia.\n\nMethodsA cross-sectional study design was used to recruit patients with cough of any duration from four selected health centers in Addis Ababa, between August and December 2016. Sputum samples were collected from patients reporting productive cough of any duration and screened for Pulmonary Tuberculosis (PTB) using smear microscopy and culture methods. Mycobacterium tuberculosis isolates obtained from culture positive samples were characterized using RD9 deletion typing.\n\nResultsMajority (39.7%) of the 725 study participants was in the age range of 20-30 years, and 5.0% were smear positive using smear microscopy. The prevalence of smear positive PTB among patients presented with cough duration of [≥]2 weeks was significantly higher compared to those patients presented with cough duration of <2 weeks (10.9% versus 0.7%; {chi}2=38.98; p=0.001). Using culture method, a total of 86 (11.9%) participants were positive for mycobacteria, and the prevalence (14.6%) of PTB among patients presented with cough duration of [≥]2 weeks was not significantly higher compared to prevalence (9.9%) in those patients presented with cough duration of <2 weeks ({chi}2=3.63; p=0.057). Molecular characterization of 86 culture positive mycobacterial isolates showed that 41 were infected with Mtb; 19(46.3%) from those who had cough duration of <2 weeks and 22(53.7%) from those who had cough duration of [≥]2 weeks.\n\nConclusionScreening of PTB using smear microscopy alone and cough duration of at least two weeks would negatively affect early diagnosis and treatment initiation in a considerable number of PTB patients who reports cough duration of <2 weeks with the potential of contributing to the spread of TB. Therefore, screening of patients with cough of any duration using both smear microscopy and culture methods is likely to contribute to the success of any effort towards the control of TB.

epidemiology↗