Yields from blood cultures of patients with suspected paratyphoid fever A.

The yield and speed of detection of Salmonella enterica serotype Paratyphi A from the blood of patients with suspected paratyphoid fever A in 13 500 paired aerobic and anaerobic bottles (AEB, ANB) that were each filled with 5 ml of blood by the BacT/ALERT 3D system were compared, and the blood bacterial counts of 1 000 probable patients were estimated by pour plate method. A total of 4 060 isolates were recovered, of these, 3 149 were recovered from both AEB and ANB, 461 from the AEB only, and 450 from the ANB only. The estimating median bacterial count in blood from 400 patients was 0.5 CFU/ml. The research findings demonstrate that the blood volume drawn is an important factor determining the yields from blood cultures. Growth of significantly more isolates was detected earlier in AEB.