Antibiotic prescription practices amongst veterinarians in Nigeria.

The high rate of antibiotic resistance constitutes a global threat to the continuous use of these drugs, because of increasing treatment failures. The aim of this study was to survey antibiotic prescription practices of veterinarians and the possible contribution to antimicrobial resistance (AMR) and antimicrobial stewardship (AMS) in Nigeria during the COVID era. This was a cross-sectional study that used a 33-question survey questionnaire administered to registered veterinarians in Nigeria. The study was both online survey and hard copy administered during the annual meeting of the veterinarians from July to October 2021. Descriptive statistics, bivariate analysis using Chi-square test were also done to analyze the results, while a two-tailed P-value of <0.05 at 95% confidence level was considered statistically significant. IBM SPSS Version 26 was used to analyze the data. A total of 172 respondents completed the online and hard copy questionnaire. Majority of the respondents engaged majorly in mixed veterinary practice (72.1%). A total of 53.5% were aware of the country's policy concerning antibiotic prescription, while majority (64.5%) do not do culture and sensitivity before antibiotic prescription. Majority (34.3%) felt that the risk of potential adverse drug reaction could affect their decision when choosing to prescribe an antibiotic to the owner. Majority (51.2%) felt that some antibiotics were over prescribed, while 26.7% opined that all antibiotics were appropriately prescribed. To improve antibiotic use and practice amongst veterinarians in Nigeria, dependence on laboratory services for antibiotic prescription, enforcement of national guidelines and monitoring of antibiotic prescription amongst the veterinarians is essential to curb over-prescription and strengthen antimicrobial stewardship.

Clinical and Socio- Demographic Risk Factors for Acquisition of Helicobacter pylori Infection in Nigeria

Background: The aim of the study was to assess clinical and socio-demographic characteristics as well as prior drug usage as risk factors for Helicobacter pylori (H. pylori) infection in Nigeria. Methods: A total of 347 respondents were surveyed by assessing their clinical and socio-demographic characteristics in comparison with the non-invasive gold standard for H. pylori diagnosis, the urea breath test (UBT). Chi-square test and odds ratio analyses were conducted in order to assess if variables such as socio-demographic factors, drug intake, and history of ulcer/gastritis/ gastric cancer within the family significantly predicted test results. Results: A total of 130 (37.5%) respondents were positive for H. pylori by the UBT. Living with more than three people in an apartment and a history of ulcer/gastritis within the family were significantly associated with H. pylori (p ≤0.05), as well as current antibiotic intake (p ≤0.05). Nationality, stay outside Nigeria, level of education, main occupation, smoking and drinking habits, sources of drinking water, number of children and history of gastric cancer had no significant association with H. pylori infection (p ≥ 0.05). Conclusion: The results of the questionnaire revealed that most socio-demographic characteristics of the respondents had no significant association with H. pylori. Overcrowding, having siblings/parents with history of ulcer/gastritis as well as prior antibiotic usage had a significant association.

Spatially Resolved Peptide-DNA Nanoassemblages for Biomarker Detection: A Synergy of DNA-Directed Immobilization and Nanografting.

Peptide microarrays are becoming a promising alternative to protein microarrays due to the challenges associated with protein immobilization and purification. Here, we put forward a novel experimental-based approach that combines DNA-directed immobilization, nanografting, and atomic force height measurements to immobilize computationally designed cyclic peptide on an ultra-flat gold substrate. This procedure yields peptide-DNA nanoarrays, which can bind to the solvent-exposed site on the Beta-2-microglobulin (ß2m).

Binary control of enzymatic cleavage of DNA origami by structural antideterminants.

Controlling DNA nanostructure interaction with protein is essential in developing nanodevices with programmable function, reactivity, and stability for biological and medical applications. Here, we show that the sequence-specific action of restriction endonucleases towards sharp triangular or rectangular DNA origami exhibits a novel, binary 'on/off' behaviour, as canonical recognition sites are either essentially fully reactive, or strongly resistant to enzymatic cutting. Moreover, introduction of structural defects in the sharp triangle can activate an otherwise unreactive site, with a site-to-defect distance of ∼50 nm. We argue that site reactivity is dependent upon programmable, mechanical coupling in the two-dimensional DNA origami, with specific structural elements, including DNA nicks and branches proximal to the sites that can function as negative(anti) determinants of reactivity. Empirically modelling the constraints to DNA degrees of freedom associated with each recognition site in the sharp triangle can rationalize the pattern of suppressed reactivity towards nine restriction endonucleases, in substantial agreement with the experimental results. These results provide a basis for a predictive understanding of structure-reactivity correlates of specific DNA nanostructures, which will allow a better understanding of the behaviour of nucleic acids under nanoscale confinement, as well as in the rational design of functional nanodevices based on self-assembling nucleic acids.

Computational design of cyclic peptides for the customized oriented immobilization of globular proteins.

The oriented immobilization of proteins, key for the development of novel responsive biomaterials, relies on the availability of effective probes. These are generally provided by standard approaches based on in vivo maturation and in vitro selection of antibodies and/or aptamers. These techniques can suffer technical problems when a non-immunogenic epitope needs to be targeted. Here we propose a strategy to circumvent this issue by in silico design. In our method molecular binders, in the form of cyclic peptides, are computationally evolved by stochastically exploring their sequence and structure space to identify high-affinity peptides for a chosen epitope of a target globular protein: here a solvent-exposed site of ß2-microglobulin (ß2m). Designed sequences were screened by explicit solvent molecular dynamics simulations (MD) followed by experimental validation. Five candidates gave dose-response surface plasmon resonance signals with dissociation constants in the micromolar range. One of them was further analyzed by means of isothermal titration calorimetry, nuclear magnetic resonance, and 250 ns of MD. Atomic-force microscopy imaging showed that this peptide is able to immobilize ß2m on a gold surface. In short, we have shown by a variety of experimental techniques that it is possible to capture a protein through an epitope of choice by computational design.

pH-Controlled Assembly of DNA Tiles.

We demonstrate a strategy to trigger and finely control the assembly of supramolecular DNA nanostructures with pH. Control is achieved via a rationally designed strand displacement circuit that responds to pH and activates a downstream DNA tile self-assembly process. We observe that the DNA structures form under neutral/basic conditions, while the self-assembly process is suppressed under acidic conditions. The strategy presented here demonstrates a modular approach toward building systems capable of processing biochemical inputs and finely controlling the assembly of DNA-based nanostructures under isothermal conditions. In particular, the presented architecture is relevant for the development of complex DNA devices able to sense and respond to molecular markers associated with abnormal metabolism.