The interplay between environmental factors, vector competence and vaccine immunodynamics as possible explanation of the 2019 yellow fever re-emergence in Nigeria.

Throughout the year 2019, Nigeria had sporadic outbreaks of yellow fever (YF), which began in the northern region of the country. Indeed, controlling the bites and population of Aedes mosquitoes and vaccination are the only effective means of preventing YF. Vectorial migration, sylvan-to-urban spillover, immunization failure and, perhaps, genetic modification of YFV could be reasons for the re-emergence of YF at the community, state and national levels. This article offers a critical review of the vector biology, YF vaccine immunodynamics and environmental drivers of YFV infections, with the aim of understanding the interplay of these factors in the re-emergence of YF and risk assessment of living in or travelling to areas where YF is endemic.

Prevalence of symptomatic urinary tract infection and bacterial spectrum of diabetic and non-diabetic patients at the two teaching hospitals in Enugu, Nigeria

Background: Diabetes mellitus is a group of metabolic disorder characterized by relative or absolute lack of insulin. When this condition is not properly managed, it can lead to complications that make diabetic patients vulnerable to urinary tract infections (UTI). The objectives of this study are to determine the prevalence of microbiologically confirmed UTI and the spectrum of uropathogens in diabetic and non-diabetic patients with clinical features of UTI attending the two tertiary hospitals in Enugu State, Nigeria. Methodology: Clean catch specimen of single mid-stream urine sample was collected from each of 60 (22 males, 38 females) diabetic and 60 (22 males, 38 females) non-diabetic patients enrolled using stratified random sampling method. The samples were cultured on standard microbiological culture media (MacConkey and Blood agar plates) and incubated aerobically at 37◦C for 24 hours. Plates with significant bacteria growth (>105 CFU/ml) were processed further for bacterial identification using conventional biochemical test scheme. Antibiotic susceptibility test (AST) of each isolate to 17 selected antibiotics was performed by the modified disc diffusion method. Results: Of the total 120 patients enrolled, 101 had bacterial pathogens isolated from their voided urine samples; 51 of 60 (85.0%) diabetics and 50 of 60 (83.3%) non-diabetics (p=0.802). Bacteria were isolated in 59.1% (13/22) of diabetic and 54.5% (12/22) of non-diabetic male patients compared to 100% (38/38) isolation rate in diabetic and non-diabetic female patients. The most frequently isolated bacteria in the diabetic patients were Proteus spp (18.6%), Klebsiella spp (16.9%) and Escherichia coli (15.5%) while the most frequently isolated bacteria among the non-diabetic patients were E. coli (30.0%), Proteus spp (26.3%) and Enterobacter spp (14.0%). Apart from Klebsiella spp which was more frequently isolated from the diabetic (16.9%) than non-diabetic patients (6%) (p=0.039), the frequency other bacterial pathogen isolation such as Proteus spp, E. coli, Enterobacter spp, Pseudomonas aeruginosa, Staphylococcus aureus and Enterococcus spp was not significantly different between the two population groups (p>0.05). The Gram-positive and Gram-negative bacteria were highly sensitive to imipenem in both diabetic and non-diabetic patients, but the isolates from both study groups exhibited low susceptibility to amoxicillin, nitrofuran- toin, cefixime and cefuroxime. Conclusion: Although the overall frequency of bacterial pathogen isolation in the diabetic and non-diabetic patients was not significantly different, females had a higher pathogen isolation rate than the males, and diabetic females had a higher frequency of polymicrobial infections compared to non-diabetic females and the male population. The high antimicrobial resistance of the isolated bacteria pathogens underscores the need for clinical microbiology laboratory testings to optimize the management of UTI in diabetic patients.