Effect of Delayed Entry into 2 Different Blood Culture Systems(BacT/Alert 3D and BACTEC 9120) on Culture Positivity / 中华医院感染学杂志

OBJECTIVE To evaluate the effect of delayed entry(0-24 h) into BacT/Alert 3D and BACTEC 9120 and the effect of 2 incubation temperatures(22 ℃ vs 35 ℃) on culture positivity.METHODS We utilized the BacT/Alert system with FA bottles and the BACTEC 9120 system with Plus(Aerobic) bottles.Four clinical bacterial species,Staphylococcus aureus,Escherichia coli,Streptococus pneumoniae,Candida albicans,were used as the test strains.and 5 ml of blood were added to each bottle.Each species was inoculated into the bottles 3 times at an inoculum size of 10 CFU/ml,102 CFU/ml and 108 CFU/ml,respectively.The inoculated bottles were cultured using the respective instruments after they were allowed to stand at room temperature(22 ℃)and 35 ℃ for 0,8,16 and 24 h.Time-to-detection and culture positivity were evaluated.RESULTS The delay in transportation of blood culture bottles stored at room temperature(22 ℃) or 35 ℃ had no effect on the recovery rate for BACTEC 3D at less than 24 h preincubation time and for BacT/Alert 9120 at less than 16h preincubation time.The positivity rate decreased significantly for BacT/Alert 9120 for 24 h of delay.Culture positivity of BacT/Alert 3D was higher than BACTEC 9120 for 24 h of delay.CONCLUSIONS The delayed entry for BacT/Alert 3D should be within 24 h,but the delayed entry for BACTEC 9120 should be within 16 h.

Comparison of Ability of BACTEC 9120 Blood Culture System to Detect Fungemia with Four Kinds of Blood Culture Bottles / 中华医院感染学杂志

OBJECTIVE To discuss the best scheme for fungemia detection by analyzing and comparing the ability and performance characteristics of the BACTEC 9120 automated blood culture system and 4 kinds of blood culture bottles in the detection of simulated fungemia.METHODS Simulated blood culture was produced using 65 fungi isolates from clinical specimens and BACTEC Plus Aerobic/F,Plus Anaerobic/F,Peds Plus/F and Myco/F Lytic blood culture bottles and detected by BACTEC 9120 automated blood culture system.The final inoculum densities were 1-5 CFU/ml blood.The(time to detection TTD) of simulated blood culture with different concentrations of suspension produced using 2 kinds of standard strains and 4 kinds of blood culture bottles was compared.RESULTS From the 260 bottles in this study 216 had growth detected by the BACTEC 9120 blood culture system.The positive rates of BACTEC Plus Aerobic/F and Anaerobic/F,which were 90.77%and 41.54%,respectively,were significantly(P