Our research suggested that satellite blood culture significantly reduces turnaround time including TI and TK(P < 0.001), which is similar with the previous studies[8, 9]. In our study, compared with medical microbiology laboratory blood culture group, TI was reduced by 3.02 h and TK was reduced by 9.76 h in satellite blood culture group. It indicated that when TI was only 3 hours earlier, TK was roughly 10 hours earlier, which is related to workflow in the lab.Schwarzenbacher et al. controled the incubation time within 1 h in satellite blood culture group, even if in the medical microbiology laboratory blood culture group, the incubation time were not more than 8h.which is better than our data. Maybe it because we didn’t train the staffs to get blood culture incubated as soon as possible. A study shown that after improving awareness of sepsis in the staff associated with improving pre-analytical phase procedures in blood culture collection,the isolation of bacteria by blood culture increased 3.25-fold. Which might explain our results and lead us to make improvements in future research. Janapatla.et al proved that there is no difference in the time to positive detection of pathogens which was observed in bottles processed during the day and after overnight delay. It's the opposite of what we thought it was and deserve more research to explore.
In Schwarzenbacher’s study, the time to know positive was more length than ours, which might owe to the staffs 24 h on duty in our hospital so that we can learn about the positive outcome quickly. However, when it comes to TA, the study didn’t demonstrate that satellite blood culture is better than medical microbiology laboratory blood culture (p = 0.056),although the median time from specimen collection to adjust antibiotic was reduced by 23.08 h in satellite blood culture group. It is contrary to Schwarzenbacher’s findings. Small sample size maybe the main reason for it.
Besides, because lack of staff during off-hours, there is an increased risk of death among patients hospitalized during off-duty.Timely intervention for positive blood culture results during weekends,the duration of hospital stay with the hospital-acquired bacteremia patients was significantly reduced during after controlling for confounders .
The probability of cultures positive result decreased of 16% while the laboratory was closed. Further, the positive rate of blood culture may decrease by 0.3% for every one hour delay from blood sample collection to incubation. We found that although the positive rate is increased in satellite blood culture group, there is no significant difference between the two groups, which is opposite of the Schwarzenbacher’s study.Small scale of patients maybe account for it. Further to analysis, we indicated that the percentage of antibiotic regimen adjustment is rising in satellite blood culture group, but there is no significant difference between the two groups. Which is correspond with results published by Kerremans et al.In addition, a study showed that blood cultures collected during 24 hours after admission yielded more positive results than those collected later. Lambregts et al reported that if blood culture had remained negative for 24 hours, The probability of bacteremia was 1.8% which may contribute to decisions on antimicrobial therapy.when the time of culture incubation is more than 48 hours, few true bloodstream infection could be detected. Evaluation of the blood volume can also improve the rate of blood culture positivity[18, 19]. So clinicians may adjust empirical antibiotic coverage at this time with little risk for subsequent bacterial pathogen detection.
Procop have shown that shorten process time (specimen collection to positive blood culture detection)could decrease hospital stays and mortality rates.However, we found that there is no significant differences in duration of ICU stay、duration of hospital stay and medical cost between the two groups, while the three factors is lower in satellite blood culture group. But these findings are consistent with research of Kerremans et al.One possible explanation is the higher proportion of old patients in satellite blood culture group. Another explanation might be the flaw of design of our study. Beside our sample size was too small. Therefore, it need to do further research to explore the impact of shorten process time on hospital stays, mortality rates, and medical cost.
Otherwise, most studies also have focused on rapid diagnostics through new technologies including Multiplex PCR、matrix-assisted laser desorption ionization-time of flight mass spectrometry、Next-Generation Sequencing、Metagenomic Sequencing[21–24].
The limitation of our study is that this was a non-randomized controlled study and the baseline was not perfectly balanced, so we cannot exclude an analytical bias. and in addition, The sample size is too small for the adjustment of antibiotic regimen、length of hospital stay and medical costs. In the future, we will design a randomized controlled study and increase the sample size to provide more robust evidence for satellite blood cultures.