Evaluation of an Initial Specimen Diversion Device (ISDD) on Rates of Blood Culture Contamination in the Emergency Department

Introduction: Blood cultures are the gold standard for identifying bloodstream infections. The Clinical and Laboratory Standards Institute recommends a blood culture contamination rate of <3%. Contamination can lead to misdiagnosis, increased length of stay and hospital costs, unnecessary testing and antibiotic use. These reasons led to the development of initial specimen diversion devices (ISDD). The purpose of this study is to evaluate the impact of an initial specimen diversion device on rates of blood culture contamination in the emergency department. Methods: This was a retrospective, multi-site study including patients who had blood cultures drawn in an emergency department. February 2018 to April 2018, when an ISDD was not utilized, was compared with June 2019 to August 2019, a period where an ISDD was being used. The primary outcome was total blood culture contamination. Secondary outcomes were total hospital cost, hospital and intensive care unit length of stay, vancomycin days of use, vancomycin serum concentrations obtained, and repeat blood cultures obtained. Results: A statistically significant difference was found in blood culture contamination rates in the Pre-ISDD group vs the ISDD group (7.47% vs 2.59%, p<0.001). None of the secondary endpoints showed a statistically significant difference. Conclusions: Implementation of an ISDD reduces blood culture contamination in a statistically significant manner. However, we were unable to capture any statistically significant differences in the secondary outcomes.

118. Eliminating Blood Culture Contamination with an Initial-specimen Diversion Device

Background Blood samples obtained via traditional venipuncture can become contaminated by superficial and deeply embedded skin flora. We evaluated the hospital-wide use of an initial-specimen diversion device (ISDD) designed to shunt these microorganisms away from the culture bottle to reduce blood culture contamination (BCC) and sequelae: false-positive central line-associated bloodstream infections (CLABSIs), repeat blood culture draws, inappropriate antibiotic usage, increased patient length-of-stay and misdiagnosis. The study aimed to show the proportion of blood cultures containing contaminants drawn by phlebotomy staff using the ISDD versus those drawn using traditional methods. Nursing staff continued to use traditional methods to draw blood cultures in the emergency department (ED) and from inpatients. Methods Over a four-month trial at Stanford Health Care (SHC), 4,462 blood cultures were drawn by phlebotomy staff using the ISDD (Steripath Gen2, Magnolia Medical Technologies) in the ED and from inpatients; 922 blood cultures were obtained by phlebotomy staff using standard methods. Additionally, 1,413 blood cultures were drawn by nursing staff using standard methods. The number of matched sets (2 bottles [aerobic/anaerobic] plus 2 bottles [aerobic/anaerobic], with total volume 40 ml) obtained through traditional methods and by the ISDD were recorded. Contaminants were defined by the National Healthcare Safety Network (NHSN). In addition, sets in which 1 out of 4 bottles contained vancomycin-resistant Enterococcus (VRE) or Candida sp. were also recorded, even though these are not considered contaminants by the NHSN. Results Of 4,462 blood cultures obtained using the ISDD there were zero contaminants found (BCC rate 0%) versus 29 contaminated sets using traditional methods (BCC rate 3.15%). Twenty-eight contaminants were observed from nursing staff blood culture draws (BCC rate 1.98%). Zero false-positive CLABSIs were associated with use of the ISDD for the trial period. No matched sets containing 1 of 4 bottles with VRE or Candida sp. were observed. Table Stanford Health Care blood culture collection methods and contamination events (March 15, 2019 - July 21, 2019) Conclusion The trial results encourage adoption of the ISDD as standard practice for blood culture at SHC. Disclosures All Authors: No reported disclosures

Reducing blood culture contamination using an initial specimen diversion device

False positive blood cultures result from contamination, consuming microbiological laboratory resources and causing unnecessary antibiotic treatment and lengthened hospitalizations. Skin sterilization has been shown to reduce contamination; however, bacteria do not only colonize the surface of human skin, but are also found in deeper tissues, requiring additional techniques to reduce contamination. An initial specimen diversion device diverts the initial 1-2 ml of blood so as to remove any potentially contaminated skin plug, thus potentially further reducing culture contamination. The device has been associated with a reduction in culture contamination over short study periods in certain populations. However, more study is needed to understand whether the effect continues over longer periods of time and in hospitalized patients. Thus, in this prospective, controlled pragmatic study, cultures were obtained from hospitalized patients using the initial specimen diversion device, with cultures taken using standard methods serving as control. In total, 671 blood cultures were obtained: 207 cultures were taken using an initial specimen diversion device, with 2 (1.0%) contaminated cultures and 464 cultures were taken without the device, with 24 (5.2%) contaminated cultures (p < 0.008). No significant difference was shown in the rate of true positive cultures. Thus, use of a diversion device was associated with reduced culture contamination in hospitalized patients over a six month period without concomitant reduction in true positive cultures. This intervention may result in a reduction in costs, antibiotic use and duration of hospitalization.