Duodenal string-capsule culture compared with bone-marrow, blood, and rectal-swab cultures for diagnosing typhoid and paratyphoid fever.

The sensitivity of duodenal string-capsule culture (DSCC) was compared to that of bone-marrow-aspirate culture (BMAC), single 3-ml blood culture (BC), and rectal-swab culture (RSC) for isolating Salmonella typhi and Salmonella paratyphi type A from patients with typhoid and paratyphoid fever. In 36 of 154 patients DSCC could not be used, usually because the patient was too ill to swallow the capsule. In the remaining 118 patients DSCC was positive in 57.6%, RSC in 35.6%, BC in 54.2%, and BMAC in 85.6%. The sensitivity of DSCC was improved by an additional 4.7% if subcultured daily for seven days. The DSCC has no advantage over the combination of RSC and BC and is inferior in sensitivity to the BMAC. However, when a BMAC cannot be obtained, the addition of the DSCC to BC and RSC can be expected to improve the isolation rate by greater than 17%, to at least 85%.