New rapid diagnostic tests for Neisseria meningitidis serogroups A, W135, C, and Y.
BACKGROUND
Outbreaks of meningococcal meningitis (meningitis caused by Neisseria meningitidis) are a major public health concern in the African "meningitis belt," which includes 21 countries from Senegal to Ethiopia. Of the several species that can cause meningitis, N. meningitidis is the most important cause of epidemics in this region. In choosing the appropriate vaccine, accurate N. meningitidis serogroup determination is key. To this end, we developed and evaluated two duplex rapid diagnostic tests (RDTs) for detecting N. meningitidis polysaccharide (PS) antigens of several important serogroups.


RESULTS
Mouse monoclonal IgG antibodies against N. meningitidis PS A, W135/Y, Y, and C were used to develop two immunochromatography duplex RDTs, RDT1 (to detect serogroups A and W135/Y) and RDT2 (to detect serogroups C and Y). Standards for Reporting of Diagnostic Accuracy criteria were used to determine diagnostic accuracy of RDTs on reference strains and cerebrospinal fluid (CSF) samples using culture and PCR, respectively, as reference tests. The cutoffs were 10(5) cfu/ml for reference strains and 1 ng/ml for PS. Sensitivities and specificities were 100% for reference strains, and 93.8%-100% for CSF serogroups A, W135, and Y in CSF. For CSF serogroup A, the positive and negative likelihood ratios (+/- 95% confidence intervals [CIs]) were 31.867 (16.1-63.1) and 0.065 (0.04-0.104), respectively, and the diagnostic odds ratio (+/- 95% CI) was 492.9 (207.2-1,172.5). For CSF serogroups W135 and Y, the positive likelihood ratio was 159.6 (51.7-493.3) Both RDTs were equally reliable at 25 degrees C and 45 degrees C.


CONCLUSIONS
These RDTs are important new bedside diagnostic tools for surveillance of meningococcus serogroups A and W135, the two serogroups that are responsible for major epidemics in Africa.
Chanteau
Suzanne
S
Institut Pasteur, Plateforme Technologique PT5, Paris, France. schanteau@cermes.org
Dartevelle
Sylvie
S
Mahamane
Ali Elhadj
AE
Djibo
Saacou
S
Boisier
Pascal
P
Nato
Farida
F
D000349:Africa / Q000453:epidemiology; D000911:Antibodies, Monoclonal; D002845:Chromatography / Q000379:methods; D005069:Evaluation Studies as Topic; D006801:Humans; D016013:Likelihood Functions; D008585:Meningitis, Meningococcal / Q000134:cerebrospinal fluid / Q000175:diagnosis* / Q000453:epidemiology / Q000276:immunology; D038381:Neisseria meningitidis, Serogroup A / Q000276:immunology / Q000302:isolation & purification*; D038542:Neisseria meningitidis, Serogroup C / Q000276:immunology / Q000302:isolation & purification*; D038582:Neisseria meningitidis, Serogroup W-135 / Q000276:immunology / Q000302:isolation & purification*; D038581:Neisseria meningitidis, Serogroup Y / Q000276:immunology / Q000302:isolation & purification*; D016133:Polymerase Chain Reaction / Q000379:methods; D011237:Predictive Value of Tests; D011446:Prospective Studies; D011933:Reagent Kits, Diagnostic; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012703:Serotyping; D013997:Time Factors
D000911:Antibodies, Monoclonal; D011933:Reagent Kits, Diagnostic