Posttreatment follow-Up of brucellosis by PCR assay

Abstract

In order to evaluate the usefulness of a peripheral blood PCR assay in the posttreatment follow-up of brucellosis, a cohort of 30 patients was studied by means of blood cultures, rose Bengal, seroagglutination, Coombs' antibrucella tests, and PCR assay at the time of diagnosis, at the end of treatment, and 2, 4, and 6 months later. Of the 29 patients whose PCR assays were initially positive, 28 (96.5%) were negative at the conclusion of the treatment. PCR was positive for the two patients who had relapses and negative for another four who had suspected but unconfirmed relapses. PCR was negative for 98.3% of the follow-up samples from those patients who had a favorable evolution. In conclusion, PCR appears to be a very useful technique, not only for the initial diagnosis of the disease, but also for posttreatment follow-up and the early detection of relapses.

FIG. 1

Agarose gel electrophoresis and ethidium bromide staining. Lanes: MW, molecular size DNA ladder (223 bp); 1, positive control (B. melitensis Rev-1); 2, no DNA added; 3 to 8, sequential samples from one of the patients with a relapse; 3, DNA from the patient at the time of diagnosis when the blood cultures were positive; 4, DNA at the conclusion of treatment; 5, DNA at the time of relapse when the blood cultures were negative; 6 to 8, DNA from the patient at the end of treatment of the relapse and 2 and 4 months later; 9, DNA from a healthy control. The photocomposition of the figure was obtained from the original Polaroid films with a ScanJed IIcx scanner (Hewlett-Packard, Corvallis, Oreg.). After the initial image was scanned and saved as a TIFF file, the file was opened in Adobe Photoshop, version 3.0 (Adobe Systems, Inc., Seattle, Wash.).