A retrospective evaluation of the performance of 2 blood culture media in detection of bloodstream infection: clinical comparison of BACTEC and BacT/Alert systems / 中华检验医学杂志

ABSTRACT

Objective To evaluate the clinical performance of the BACTEC Plus aerobic,BACTEC Lytic anaerobic,BacT/Alert aerobic and anaerobic blood culture media in detection of bloodstream infections.Methods Retrospective study was conducted.A total of four blood culture bottles from each inpatient with suspected bloodstream infections were collected and analyzed from June 2013 to September 2015 in Peking University People's Hospital.The four bottles,including BACTEC Plus aerobic,BACTEC Lytic anaerobic,BacT/Alert FA aerobic and BacT/Alert FN anaerobic media,and was incubated for 5 days in the BacT/Alert 3D and BACTEC FX instruments,respectively.Time to detection (TTD) and positive rate in detecting bacteria of the two systems were evaluated by Wilcoxon test and Chi-square test.Results Among 2 189 total cultures collected,20 were excluded because of blood shortage and 201 (9.27％) were positive for pathogens.The positive rates of BACTEC Plus aerobic media and BacT/Alert FA aerobic media were 75.3％ (140/186) and 69.4％ (129/186) (x2 =1.625,P=0.202),respectively.While,the positive rates of BacT/Alert FN anaerobic media and BACTEC Lytic anaerobic media were 81.8％ (99/121) and 63.6％ (77/121) for total organisms,respectively (x2 =10.083,P =0.001).A significant difference in TTD was detected in BACTEC Plus aerobic media[11.0 (8.0-16.0) h] and BacT/Alert FA aerobic media[13.9 (10.4-18.7) h] (Z =-5.240,P ＜ 0.001).BACTEC Lyric anaerobic media[8.0(7.0-10.0) h] had a shorter TTD (Z =-4.299,P ＜ 0.001) than BacT/Alert FN anaerobic media[11.3(9.3-12.7) h].The positive rates of BACTEC and BacT/Alert system were 74.13％ (149/201) and 74.63％ (150/201),respectively,compared with taking one set from each system.Conclusions BACTEC media has a shorter TTD and almost the same bacterial recovery,and lower false positive rate than the BacT/ Alert media.