Validation of xMAP SARS-CoV-2 Multi-Antigen IgG assay in Nigeria

Objective: There is a need for reliable serological assays to determine accurate estimates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) seroprevalence. Most single target antigen assays have shown some limitations in Africa. To assess the performance of a multi-antigen assay, we evaluated a commercially available SARS-CoV-2 Multi-Antigen IgG assay for human coronavirus disease 2019 (COVID-19) in Nigeria. / Methods: Validation of the xMAP SARS-CoV-2 Multi-Antigen IgG assay was carried out using well-characterized SARS-CoV-2 reverse transcription polymerase chain reactive positive (97) and pre-COVID-19 pandemic (86) plasma panels. Cross-reactivity was assessed using pre-COVID-19 pandemic plasma specimens (213) from the 2018 Nigeria HIV/AIDS Indicator and Impact Survey (NAIIS). / Results: The overall sensitivity of the xMAP SARS-CoV-2 Multi-Antigen IgG assay was 75.3% [95% CI: 65.8%– 82.8%] and specificity was 99.0% [95% CI: 96.8%– 99.7%]. The sensitivity estimate increased to 83.3% [95% CI: 70.4%– 91.3%] for specimens >14 days post-confirmation of diagnosis. However, using the NAIIS pre-pandemic specimens, the false positivity rate was 1.4% (3/213). / Conclusions: Our results showed overall lower sensitivity and a comparable specificity with the manufacturer’s validation. There appears to be less cross-reactivity with NAIIS pre-pandemic COVID-19 specimens using the xMAP SARS-CoV-2 Multi-Antigen IgG assay. In-country SARS-CoV-2 serology assay validation can help guide the best choice of assays in Africa

Bacteriological Evaluation Of Pre-Cut Fruits Sold In Kano Metropolis, Kano State, Nigeria

One hundred and fifty (150) pre-cut fruit samples comprising of Pineapples (50), Paw-paw (50) and Watermelon (50) at the point of standretail outlets were tested by standard bacteriological methods to determine bacterial contamination of the fruits. Out of these 150 examined136 (90.67%) were contaminated with bacteria. The bacterial distribution were; Escherichia coli 69 (46.00%), Staphylococcus aureus 29(19.33%), Salmonella species 13 (8.67%), Proteus species18 (12.00%), Enterobacter aerogenes 3 (2.00%), Klebsiella pneumoniae 2 (1.33%)and Pseudomonas aeruginosa 2 (1.33%). Among the 50 Pineapple pre-cuts, Escherichia coli 26 (17.33%), Staphylococcus aureus 6 (4.00%),Salmonella species 7 (4.67%), Proteus species 9 (6.00%), Pseudomonas aeruginosa 2 (1.33%); the 50 Watermelon had Escherchia coli 22(14.67%), Staphylococcus aureus 13 (8.67%), Salmonella species 3 (2.00%), Proteus species 5 (3.33%), Enterobacter aerogenes 2 (1.33%),Klebsiella species 2 (1.33%). Of the 50 Paw-paw pre-cuts were; Escherichia coli 21 (14.00%), Staphylococcus aureus 10 (6.67%), Salmonellaspecies 3 (2.00%), Proteus species 4 (2.67%), Enterobacter aerogenes 1 (0.67%) were isolated. The findings in this study have shown thatthe food vendors failed to adopt adequate hygiene for food handling and thus, suggest that the quality of all the pre-cut fruits sold at theretail outlets were not bacteriologically satisfactory. The public health risks associated with these pre-cut fruits may suggest that these fruitscould serve as the vehicles for foodborne illnesses. This study has shown the need to educate the vendors on how to protect utensils andfruits to avoid contamination and spoilag