Diagnostic and prognostic value of an immunofluorescent assay for melioidosis

Melioidosis caused by Burkholderia pseudomallei is endemic in southeast Asi a. The clinical manifestations range from wound infections to acute septice mia. In some cases, recurrence can also occur following complete recovery. Case fatality rates are high and a major factor is the delay in the culture and identification of the bacterium. An immunofluorescent assay (IFAT) usi ng whole-cell antigen for the detection of total antibodies to B. pseudomal lei was tested with 650 sera. Using a cut-off value of 1:80, 66 sera from c ulture-confirmed cases were positive with titers greater than or equal to 3 20. In another 523 sera from patients in which no other etiology could be f ound, 149 (23.4%) were positive. To monitor disease activity, persistence o f antibody levels was investigated on 61 serial sera samples collected from 14 other confirmed cases on follow-up visits while on oral maintenance the rapy. The IFAT demonstrated a reduction in titers in cases of localized inf ections, suggesting that either the infection was being resolved or arreste d while septicemic patients maintained high IFAT titers on follow-up, sugge sting the possibility of continuous sequestration of antigen from an intrac ellular source.