Deteccao de IgG antitoxina colerica por ELISA e sua utilidade no diagnostico de surtos de epidemicosSergio Stakteas; Jorge Barreto

ABSTRACT

The authors evaluated the utility of IgG cholera anti-toxin for serological diagnosis of Vibrio cholerae 01 El Tor infection during an epidemic which occurred in the city of Maputo in 1992. The IgG anti-toxin was sought in serum of hospitalized cholera patients (n= 172; average length of internment= 3 days) and in healthy adult individuals observed during the previous inter-epidemic period (n= 100) through an immunoenzyme assay (ELISA) previously described by Young and Cols (Infection and Immunity 27(1) 492-496; 1980) and modified by Levine and Cols (J. Clin. Microbiol. 21 174-179; 1985). Taking with reference to the bacteriological culture of stools samples; the ELISA showed sensitivity of 71.1 and a specificity of 97.3 when applied in the first three days of hospitalization. 20/28 patients with previous isolation of Vibrio cholerae 01 and negative serology; showed a pattern of ELISA seroconversion for cholera anti-toxin when retested 4-8 days after hospitalization. Taking into account these results; the ELISA showed an overall sensitivity of 91.8 and a specificity of 97.3. The presence of IgG cholera anti-toxin in the acute or convalescent phases of choleric disease has a high predictive value for the infection (ppv= 97.8; 95 CI95.6-100). A negative serological result in the acute phase requires a second ELISA test 4-8 days later to confirm an antibody seroconversion. This ELISA could provide provisional diagnosis of c cholera outbreak and information about its course