A rapid dot immunoassay for detecting the Brazilian purpuric fever clone of Haemophilus influenzae biogroup aegyptius with a "flow through" device.
Brazilian purpuric fever (BPF) is a highly fatal pediatric disease that may follow an episode of purulent conjunctivitis caused by a virulent clone of Haemophilus influenzae biogroup aegyptius (Hae). Oral rifampin prophylaxis, by eliminating carriage of the BPF clone in children with conjunctivitis, may prevent onset of the systemic disease. A test to detect the BPF clone directly from eye swabs could identify those in need of prophylaxis. This is a preliminary report of a rapid dot immunoassay performed on a "flow-through" cartridge that was developed for use under field conditions. The test is based upon recognition of a unique epitope of the 25-kDa pilin protein on the surface of BPF clone cells by a monoclonal antibody. With 36 laboratory-maintained cultures of Hae (15 clone isolates and 21 others), sensitivity of the assay was 67% and specificity was 95%. When fimbrial-enriched (25-kDa+) phenotypes of five false-negative clone strains were prepared for use as test antigens, sensitivity rose to 100%. Evaluation of the immunoassay under field conditions is necessary to prove its efficacy.
Ajello
G W
GW
Division of Bacterial and Mycotic Diseases, National Center for Infectious Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30333, USA.
Matar
G M
GM
Swaminathan
B
B
Bibb
W F
WF
Helsel
L O
LO
Perkins
B A
BA
D003234:Conjunctivitis, Bacterial / Q000382:microbiology; D006192:Haemophilus Infections / Q000382:microbiology*; D006193:Haemophilus influenzae / Q000302:isolation & purification*; D006801:Humans; D015151:Immunoblotting / Q000379:methods*; D012680:Sensitivity and Specificity; D013997:Time Factors