Biology subjects

Teferi, M.

Publications and source records attributed to Teferi, M..

3 recordsLinked to original sources

bioRxiv2020

The genomic epidemiology of multi-drug resistant nontyphoidal Salmonella causing invasive disease in sub-Saharan Africa

BackgroundInvasive nontyphoidal Salmonella (iNTS) is one of the leading causes of bacteraemia in sub-Saharan Africa. Multi-drug resistance (MDR) and further resistance to third generation cephalosporins and fluoroquinolones have emerged in multiple iNTS serotypes. Molecular epidemiological investigations of nontyphoidal Salmonella are needed to better understand the genetic characteristics and transmission dynamics associated with major MDR iNTS serotypes across the continent. MethodsA total of 166 nontyphoidal Salmonella isolates causing invasive disease were collected from a multi-centre study in eight African countries between 2010 and 2014, and whole-genome sequenced to investigate the geographical distribution, antimicrobial genetic determinants and population structure of iNTS serotypes-genotypes. Phylogeographical reconstruction was further conducted in context of the existing genomic framework of iNTS serotypes Typhimurium and Enteritidis. Population-based incidence of MDR-iNTS disease was also estimated. ResultsSalmonella enterica subsp. Enterica serotype Typhimurium (S. Typhimurium) sequence-type (ST) 313 and Salmonella enterica subsp. Enterica serotype Enteritidis (S. Enteritidis) ST11 were predominant, and both exhibited high frequencies of MDR. Salmonella enterica subsp. Enterica serotype Dublin (S. Dublin) ST10 emerged in West Africa. Mutations in the gyrA gene were identified in S. Enteritidis and S. Typhimurium in Ghana; and ST313 carrying blaCTX-M-15 was found in Kenya. Inter-country transmission of MDR ST313 lineage II and the West African Clade of MDR ST11 between Ghana and neighbouring countries including Mali, Burkina Faso, and Nigeria were evident. The incidence of MDR-iNTS disease exceeded 100/100,000-person years-of-observation (PYO) in children aged <5 years in several West African countries. ConclusionsMultiple MDR iNTS serotypes-sequence types, predominantly S. Typhimurium ST313 and S. Enteritidis ST11, are co-circulating in sub-Saharan Africa with evidence of transmission between West African countries. The development of safe and effective iNTS vaccines coupled with appropriate antimicrobial stewardship and adequate epidemiological monitoring are essential to limit the impact of these pathogens in Africa.

genomics↗

bioRxiv2020

Development of a novel connectivity-based electric-field modelling approach for individualized targeting of transcranial magnetic stimulation treatment.

BackgroundResting state functional connectivity (rsFC) offers promise for individualizing stimulation targets for transcranial magnetic stimulation (TMS) treatments. However current targeting approaches do not account for non-focal TMS effects or large-scale connectivity patterns. To overcome these limitations, we propose a novel targeting optimization approach that combines whole-brain rsFC and electric-field (e-field) modelling to identify single-subject, symptom-specific TMS targets. MethodsIn this proof of concept study, we recruited 91 anxious misery (AM) patients and 25 controls. We measured depression symptoms (MADRS/HAMD) and recorded rsFC. We used a PCA regression to predict symptoms from rsFC and estimate the parameter vector, for input into our e-field augmented model. We modeled 17 left dlPFC and 7 M1 sites using 24 equally spaced coil orientations. We computed single-subject predicted {Delta}MADRS/HAMD scores for each site/orientation using the e-field augmented model, which comprises a linear combination of the following elementwise products 1) the estimated connectivity/symptom coefficients, 2) a vectorized e-field model for site/orientation, 3) the pre-treatment rsFC matrix, scaled by a proportionality constant. ResultsIn AM patients, our pre-stimulation connectivity-based model predicted a significant decrease depression for sites near BA46, but not M1 for coil orientations perpendicular to the cortical gyrus. In control subjects, no site/orientation combination showed a significant predicted change. DiscussionThese results corroborate previous work suggesting the efficacy of left dlPFC stimulation for depression treatment, and predict better outcomes with individualized targeting. They also suggest that our novel connectivity-based e-field modelling approach may effectively identify potential TMS treatment responders and individualize TMS targeting to maximize the therapeutic impact.

neuroscience↗

bioRxiv2019

Intestinal parasitosis, anaemia and risk factors among preschool children in Tigray Region, Northern Ethiopia.

BackgroundIntestinal parasitic infections (IPIs) and anaemia are major health problems. This study assessed the prevalence of IPI, anaemia and associated factors among pre-school children in rural areas of the Tigray region, northern Ethiopia.\n\nMethodology/Principal FindingA community based cross-sectional study was conducted among 610 pre-school children in rural communities of Northern Ethiopia from June 2017 to August 2017. Stool specimens were examined for the presence of trophozoites, cysts, oocysts, and ova using direct, formal-ethyl acetate concentration, Kato-Katz, and Ziehl-Neelsen techniques. Haemoglobin was measured using a HemoCue spectrometer. Among the 610 pre-school children participated in the study, prevalence of IPIs and anaemia were 58% (95% CI: 54.1-61.9%) and 21{middle dot}6% (95% CI: 18{middle dot}5% to 25{middle dot}1%), respectively. Single, double, and triple parasitic infections were seen in 249 (41%, 95% CI: 37% to 45%), 83 (14%, 95% CI: 11% to 17%), and 22 (3.6%, 95% CI: 2.4% to 5.4%) children, respectively. Of the seven intestinal parasitic organisms recorded from the participants, Entamoeba histolytica/dispar was the most prevalent 220 (36.1%) followed by Giardia lamblia 128 (20.1%), and Hymenolepis nana 102 (16.7%). Mixed infections were common among G. lamblia, E. histolytica/dispar and Cryptosporidium spp. oocyst. Age 48-59 months prevalence ratio (PR = 1{middle dot}078, P=0{middle dot}009), child deworming (PR= 1.2; 95% CI=1.00-1.4, p= 0.045), and having two or more children aged under five (PR=0.76, 95% CI= 0.61-0.95, p=0.015) were independent predictors for IPIs. Anaemia was associated with proper disposal of solid waste (PR= 1.5, 95% CI=0.1.1-2.10, p=0.009). Eating raw meat (PR=0.49, 95% CI=0.45-0.54, p=0.000), any maternal education (PR=0.64 95% CI=0.52-0.79, p=0.000), and household water treatment (PR=0.75, 95% CI=0.56-1.0, p=0.044) were associated with lower prevalence of anaemia.\n\nConclusionsMore than half of the children were infected with intestinal parasites and one in five were anaemic. This study has identified a number of potentially modifiable risk factors to address the significant prevalence of IPIs and anaemia in these children. Improvements in sanitation, clean water, hand hygiene, maternal education could address both short and long-term consequences of these conditions in this vulnerable population.\n\nAuthor SummaryIntestinal parasitic infection and anaemia are public health problems in developing counties. Children due to their immature immune systems and frequent exposure to unhygienic environments are at high risk which in turn put them at an increased risk of malnutrition and growth deficits. Similarly, childhood anaemia impairs physical growth, impairs immune function and weakens motor development. The finding of this study reveals more than half of the children were infected. Entamoeba histolytica/dispar, Giardia lamblia and Hymenolepis nana were dominant parasites. Multiple infections was common among Giardia lamblia, Entamoeba histolytica/dispar and Cryptosporidium spp. Oocyst. Children aged 48-59 months were more infected with intestinal parasites. Soli transmitted helminths in this study was low. 21.5% of the children were anaemic and was associated with disposal of solid waste and presence of domestic animals. However, Eating raw meat, maternal education and household water treatment were found preventive of anaemia in the study. It seems worth understanding the prevalence and effects of parasitic infection and anaemia in this vulnerable group to design an appropriate interventions. Finally, if parasite transmission and anaemia is to be significantly prevented control programs such as improving sanitation, clean water, maternal education may be critical in this vulnerable age groups.

microbiology↗