This review aimed to assess the occurrence of false-positive serological reaction between dengue and coronavirus disease 2019 (COVID-19) and its implications for diagnosis. Evidence syntheses were conducted by systematically reviewing available literature using multiple databases, including Web of Science, PubMed, Google Scholar and medRxiv. Among a total of 16 presented cases from clinical settings, cross-reaction to COVID-19 serological tests was observed in two (12.5%) dengue-positive patients, while 14 patients (87.5%) confirmed positive for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) showed a cross-reaction with dengue serological tests, leading to misdiagnosis and mismanagement by attending clinicians. Of 1789 SARS-CoV-2-positive sera, cross-reaction to dengue serological tests was observed in 180 sera (10%), which is higher than the cross-reaction observed for SARS-CoV-2 in archived pre-COVID-19 sera positive for a dengue infection (75 of 811, 9.2%, P = 0.674). Clinicians in tropical regions are therefore advised to interpret serological tests with caution and use a more pragmatic approach to triage these infections.

Background Rapid emergence of multidrug resistant Staphylococcus aureus has resulted to difficulty in treatment of infections caused by such strains. The aim of this meta-analysis study was to determine the pooled prevalence of resistance of S. aureus to different antibiotics in Nigeria. Methods Literature search for studies was done using Google scholar, PubMed, Science direct, and African Journal Online. The prevalence of S. aureus resistance to different antibiotics was evaluated using the meta-analysis proportion command in MedCalc software version 20.0 adopting a rand effect model. I2 statistic and Egger test in MedCalc was used to evaluate the heterogeneity and the presence of publication bias among studies respectively. Results A total of 40, 682 studies were retrieved through the database search of which 98 studies met the study inclusion criteria. Prevalence of resistance of S. aureus to different antibiotics ranges from 13 to 82%. Results showed a very high degree of resistance to penicillin G (82% [95% confidence interval (CI) 61%, 0.96%]), cloxacillin (77% [95% CI 64%, 88%]), amoxacillin (74% [95% CI 66%, 81%]), cefuroxime (69% [95% CI 51%, 85%]), ampicillin (68% [95% CI 53%, 81%]). Moderately resistance to erythromycin (47% [95% CI 40%, 53%]), chloramphenicol (47% [95% CI 37%, 56%]), methicillin (46% [95% CI 37%, 56%]), ofloxacin (24% [95% CI 18%, 31%]) and rifampicin 24% [95% CI 6%, 48%]). Low resistance was observed in vancomycin 13% (95% CI 7%, 21%). For each individual meta-analysis, high heterogeneity was observed with I2 range (79.36–98.60%) at p-values ≤ 0.01). Egger’s tests for regression intercept in funnel plots indicated no evidence of publication bias. Conclusion This meta-analysis study established that S. aureus in Nigeria has developed resistance to commonly used antibiotics such as the beta-lactam class antibiotics, sulphonamides, tetracyclines, chloramphenicol, and vancomycin. Hence it is imperative to develop programs to promote rational use of antimicrobial agents, infection prevention and control to reduce the incidence of antimicrobial resistance.

Rapid emergence and quick evolution of drug-resistant and aggressive mycobacterial strains have resulted in the present antimycobacterial drug crisis and the persistence of tuberculosis as a major public health problem. Green/biological nanotechnologies constitute an interesting area of research for discovering antimycobacterial agents. This review focused on the biological (green) synthesis of silver nanoparticles (AgNPs) as an alternative source of antimycobacterial agents. Data for this study were searched and screened from three electronic databases (Google Scholar, PubMed and ScienceDirect) following the Preferred Reporting Items for Systematic Reviews and Meta-analyses flowchart. Data from in total 17 eligible studies were reported in this systematic review. Twelve of the 17 studies used plants to fabricate AgNPs, whereas the remaining five studies used microorganisms (bacteria and/or fungi). Silver as part of silver nitrate (AgNO3) was the metal precursor reported for the synthesis of AgNPs in these studies. Silver nanoparticles were mostly spherical, with sizes ranging from 12 to 140 nm. Results based on minimum inhibitory concentrations varied between studies and were divided into three groups: (i) those more effective than the antibiotic (controls), (ii) those more effective than plant extracts, and (iii) those less effective than the antibiotic controls. In addition, little or no cytotoxicity effects were reported. Silver nanoparticles were also shown to be highly specific or selective toward mycobacterial strains. This systematic review highlights the antimycobacterial potential of biologically synthesized AgNPs, underscoring the possibility of discovering/developing new antimycobacterial agents using biological synthesis approaches with less toxicity and high selectivity.