Rapid enzyme-linked immunosorbent assay for the diagnosis of human brucellosis in surveillance and clinical settings in Egypt.
OBJECTIVE
To optimize and standardize an enzyme-linked immunosorbent assay (ELISA) for rapid diagnosis of human brucellosis in clinical cases identified during a surveillance study for acute febrile illness (AFI).


METHODS
Serum samples from patients presenting with AFI at 13 fever hospitals across Egypt between 1999 and 2003 were kept frozen at NAMRU-3 and used in this study. The assay was evaluated in 5 subject groups: brucellosis cases confirmed by blood culture (group I, n=202) 87% positive by standard tube agglutination test (TA), brucellosis cases exclusively confirmed by TA (group II, n=218), blood cultures from AFI cases positive for bacterial species other than Brucella (group III, n=103), AFI cases with unexplained etiologies (group IV, n=654), and healthy volunteers (group V, n=50). All members of groups III-V were negative for brucellosis by TA.


RESULTS
Sensitivity and specificity of ELISA for total specific antibodies were >=96% versus 87% for TA as compared to microbial culture, the current gold standard method for Brucella identification. Assessment of Brucella antibody classes by ELISA in random subsets of the 5 groups showed significantly high (p>0.001) levels of anti Brucella IgG (>=81%) and IgM (>=90%) in groups I and II only.


CONCLUSIONS
The obtained sensitivity and specificity results indicate that our ELISA is more suitable for AFI surveillance and clinical settings than blood culture and TA. The developed assay is also cost-effective, easier to use, faster, and the coated plates can be stocked for at least 8 months, providing a potential for field use and automation.
Fadeel
Moustafa A
MA
United States Naval Medical Research Unit-3, PSC 452, Box 5000 (Attn: Code 304A), FPO AE 09835-0007, USA. fadeelm@namru3.med.navy.mil
Wasfy
Momtaz O
MO
Pimentel
Guillermo
G
Klena
John D
JD
Mahoney
Francis J
FJ
Hajjeh
Rana A
RA
D000293:Adolescent; D000328:Adult; D000907:Antibodies, Bacterial / Q000032:analysis; D002002:Brucella / Q000302:isolation & purification*; D002006:Brucellosis / Q000097:blood / Q000175:diagnosis* / Q000453:epidemiology; D002648:Child; D002675:Child, Preschool; D004534:Egypt / Q000453:epidemiology; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D006801:Humans; D007075:Immunoglobulin M / Q000032:analysis; D008297:Male; D008875:Middle Aged; D011159:Population Surveillance; D011237:Predictive Value of Tests
D000907:Antibodies, Bacterial; D007075:Immunoglobulin M