DETECTION OF LEPTOSPIRES IN URINE BY PCR FOR EARLY DIAGNOSIS OF LEPTOSPIROSIS

We tested urine samples from patients at different stages of current l eptospirosis and thereafter to determine whether use of the PCR for de tection of leptospires in urine can be a valuable alternative to cultu ring. The procedure of DNA extraction and subsequent PCR applied to 15 freshly voided urine samples proved to be twice as sensitive as cultu ring. Overall, we were able to detect leptospires in approximately 90% (26 of 29) of the urine samples. Urine and serum samples were obtaine d from seven patients, before the eighth day of illness. Although it i s generally assumed that leptospiruria starts approximately in the sec ond week of illness, we were able to detect leptospires in all of thes e early urine samples. In contrast, only two of seven corresponding se rum samples gave positive PCR results, which suggests that PCR analysi s of urine can be more successful for early diagnosis of leptospirosis than PCR analysis of serum. Urine samples from six patients who had b een treated with antibiotics at the time of illness were positive by P CR, implying that the patients were still shedding leptospires in thei r urine despite treatment. Some of these samples were even taken years after the infection, indicating that shedding of leptospires in urine may last much longer than is generally assumed. We conclude that dete ction of leptospires in urine with PCR is a promising approach for ear ly diagnosis of leptospirosis and may also be useful in studying long- term shedding.