The present pandemic has posed a crisis to the economy of the world and the health sector. Therefore, the race to expand research to understand some good molecular targets for vaccine and therapeutic development for SARS-CoV-2 is inevitable. The newly discovered coronavirus 2019 (COVID-19) is a positive sense, single-stranded RNA, and enveloped virus, assigned to the beta CoV genus. The virus (SARS-CoV-2) is more infectious than the previously detected coronaviruses (MERS and SARS). Findings from many studies have revealed that S protein and RdRp are good targets for drug repositioning, novel therapeutic development (antibodies and small molecule drugs), and vaccine discovery. Therapeutics such as chloroquine, convalescent plasma, monoclonal antibodies, spike binding peptides, and small molecules could alter the ability of S protein to bind to the ACE-2 receptor, and drugs such as remdesivir (targeting SARS-CoV-2 RdRp), favipir, and Emetine could prevent SASR-CoV-2 RNA synthesis. The novel vaccines such as mRNA1273 (Moderna), 3LNP-mRNAs (Pfizer/BioNTech), and ChAdOx1-S (University of Oxford/Astra Zeneca) targeting S protein have proven to be effective in combating the present pandemic. Further exploration of the potential of S protein and RdRp is crucial in fighting the present pandemic.

The study of transporters is highly challenging, as they cannot be isolated or studied in suspension, requiring a cellular or vesicular system, and, when mediated by more than one carrier, difficult to interpret. Nucleoside analogues are important drug candidates, and all protozoan pathogens express multiple equilibrative nucleoside transporter (ENT) genes. We have therefore developed a system for the routine expression of nucleoside transporters, using CRISPR/cas9 to delete both copies of all three nucleoside transporters from Leishmania mexicana (ΔNT1.1/1.2/2 (SUPKO)). SUPKO grew at the same rate as the parental strain and displayed no apparent deficiencies, owing to the cells’ ability to synthesize pyrimidines, and the expression of the LmexNT3 purine nucleobase transporter. Nucleoside transport was barely measurable in SUPKO, but reintroduction of L. mexicana NT1.1, NT1.2, and NT2 restored uptake. Thus, SUPKO provides an ideal null background for the expression and characterization of single ENT transporter genes in isolation. Similarly, an LmexNT3-KO strain provides a null background for transport of purine nucleobases and was used for the functional characterization of T. cruzi NB2, which was determined to be adenine-specific. A 5-fluorouracil-resistant strain (Lmex5FURes) displayed null transport for uracil and 5FU, and was used to express the Aspergillus nidulans uracil transporter FurD.

Background and objective: Listeria sp. is a ubiquitous and frequently isolated foodborne pathogen. The prevalence of Listeria sp in raw beef and chevon sold in Lafia Nigeria, as well as their antibiotic susceptibility profile was evaluated. Methods: A total 104 samples comprising of 52 raw beef and 52 chevon were obtained from street vendors (hawkers), Shinge abattoir, Lafia old market and Lafia Modern Market. Isolation of Listeria sp. was performed on Listeria Selective Agar, following enrichment in supplemented Listeria Selective Broth. Identification of Listeria sp. was carried out by cultural and biochemical methods. Antimicrobial susceptibility of isolated L. monocytogenes was performed by standard disk diffusion method. Chi-square test was used to determine association between contamination levels at p=0.05. Results: Seven types of Listeria sp. were isolated. L. monocytogenes and L. ivanovii were the most frequently isolated contaminants in all meat types and from all sample sources. L. monocytogenes was isolated with a frequency of 64.4% (67/104) in the meat samples. Beef samples had the highest listerial contamination with a frequency of 58.2% (78/134) compared to chevon which had a listerial frequency of 41.8% (56/134). Resistance of L. monocytogenes to streptomycin and sparfloxacin was 58.2% and 55.2% respectively. Resistance to ampicillin (34.3%) and gentamicin (20.9%) was also observed. Resistances to multiple antimicrobials were detected in 11 L. monocytogenes isolates. Conclusion: The study demonstrated that the raw meat sold in Lafia was contaminated with several Listeria sp. L. monocytogenes showed high rate of resistance to several antimicrobial agents used for the treatment of listerial infection. Appropriate regulation and monitoring of livestock rearing and meat retailing practices are advocated to safeguard the health of consumers. Ibrahim Med. Coll. J. 2019; 13(2): 1-8

The poultry industry is important in boosting food sustainability of a population; however, the poultry environment and products are susceptible to pathogen contamination arising from poor farm hygienic conditions. This study investigated the prevalence, antimicrobial resistance and virulence profile of Proteus species from the environment and products of four selected poultry farms in Lafia, Nasarawa State. Farm samples (n =216) comprising feed (64), drinking water (64) and swabs from eggshells (88) were collected and analysed for detection of Proteus species using cultural, biochemical and microscopic techniques. Antibiotics susceptibilities of isolates were also determined, and virulence genes were confirmed using Polymerase Chain Reaction. Of the total studied samples, 34.26% (74/216) were positive for Proteus species. Proteus species were more prevalent in drinking water samples (37.84%) and feed samples (33.78%) and least prevalent in eggshells (28.38%). Proteus species (n= 74) comprised P. mirabilis 78% (58/74) and Proteus vulgaris 22% (16/74). P. mirabilis was markedly higher than P. vulgaris in all the four farms sampled. Farms A and D had the highest prevalence of Proteus species, while Farms A and C (80%), and Farm D (25) has the highest prevalence of P. mirabilis and P. vulgaris respectively. The isolates’ prevalence rate within and between farms, sample type, and species was not statistically significantly different (p≥0.05) from the other farms. Isolates were 100% susceptible to Amikacin and showed the highest resistance (25.7%) to tetracycline. Molecular analysis of the virulence genes of Proteus species revealed the presence of rsbA, ureC and luxS virulent genes in all the test isolates. Data generated indicates a high level of multidrug-resistant pathogenic strains of Proteus circulating in poultry farms in Lafia, Nigeria, which potentiates a significant risk of transmission of pathogenic Proteus via the food chain.

Medicinal plants have been used as effective approaches to manage multidrug resistant pathogens, including infectious agents that cause nosocomial infections. This study aimed to investigate the antimicrobial potentials of ethanolic extracts of Ricinus comunis, Swietenia mahogani and Crusentia cujete against five multidrug resistant nosocomial pathogens namely; Staphylococcus aureus, Pseudomonas sp., Klebsiella sp., Escherichia coli and Candida sp., which were isolated from hospital fomites. Using standard microbiological methods, fomite swab samples from ward beddings and door handles from the casualty, women, and children ward of Dalhatu-Araf Specialist Hospital, Lafia, Nigeria, were assessed. A total of 251 microbial isolates, consisting of 8 bacterial and 6 fungal genera were recovered. The highest frequency of microbial pathogens was recorded in the casualty unit (98[39%]), followed by the women's unit (90[36%]), while the children's ward (63[25%]) was the least contaminated. S. aureus (25[42%]) and Aspergillus sp. (43[72%]) were the most isolated bacteria and fungi; respectively, while Salmonella sp. (7[12%]) and Trichoderma sp. (9[15%]) were the least isolated. However, there were no significantly statistical differences across wards and microbial isolates. The five selected isolates were tested for in vitro susceptibility against several standard antibiotics to check their multiple drug resistance. The tested microorganisms exhibited various levels of multidrug resistance patterns except for Candida sp. which was resistant to two classes of antibiotics (azole group and griseofulvin). On the other hand, Klebsiella sp. was resistant to eight antibiotics of four classes. The ethanolic leaf extract of C. cujete was more effective against all the selected microbial pathogens, while the bark extract of S. mahogani was substantially effective. R. comunis exhibited no inhibitory potential against any of the tested pathogens. All the plant extracts were not as effective against the tested microorganisms as the conventional antibiotics that were used as positive controls. Results obtained indicate the risk of nosocomial infections caused by multidrug resistant pathogens originating from the hospital environment. Good hygienic practices, public awareness on nosocomial infections and further research into ethnomedicine are hereby recommended.