Study on blood culture in blood of paratyphoid fever A patients

Abstract

Objective To compare the yield and speed of detection of Salmonella subsp, enterica serotypo Paratyphi A from the blood of patients with suspected paratyphoid fever A. Methods With the BacT/ALERT 3D system and paired aerobic and anaerobic bottles (AEB, ANB) that were each filled with 5 ml of blood, the blood culture of 13 500 suspected paratyphoid fever A patients were performed. Results A total of 4 060 isolates were detected. About 3 149 were detected from both AEB and ANB. Four hundred and sixty-one isolates were detected only from the AEB and 450 were only from the ANB. The detection rates of the AEB and ANB were all 26.7% (χ =0.023, P=0.880). The increased detection rate attributed to the additional blood volume in the AEB and ANB were 11.3% and 11.1%, respectively. The detection speed differed between the two medium formulations. The time to detection was (23.66±15.89) h and (25.48±16.92) h for3 149 isolates, respectively (t=7.007, P<0.01).The mean time to detection was 31.80±20. 97 for 461 isolates discovered with AEB and (33.45±20.72) h for 450 isolates discovered with ANB. Conclusion The blood volume is an important factor in determining the detection rate of blood culture. Although no statistical difference for positive rate was found between the AEB and ANB, more isolates was detected earlier in AEB. Key words: Paratyphoid fever; Salmonella, paratyphi A; Colony count, microbial; Bacteriological techniques