Clinical Impact of a Real-Time PCR Assay for Rapid Identification of Staphylococcal Bacteremia

Abstract

The purpose of this study was to evaluate the impact of real-time PCR reporting both on timely identification of clustered Grampositive cocci (GPC) in blood cultures and on appropriate antibiotic treatment. This retrospective, interventional cohort study evaluated inpatients with blood cultures positive for GPC in the pre-PCR (15 January 2009 to 14 January 2010) and post-PCR (15 January 2010 to 14 January 2011) periods. Post-PCR implementation, laboratory services completed batched PCR; results other than methicillin-resistant Staphylococcus aureus (MRSA) were reported in the electronic medical record without additional interventions. The assay's sensitivity and specificity, time to identification of staphylococcal bacteremia, and clinically relevant outcomes, including time to optimal antibiotic therapy, were evaluated. Demographic information was also collected and analyzed. Sixty-eight and 58 patients with Staphylococcus aureus bacteremia from the pre-and post-PCR periods, respectively, met inclusion criteria. Similar numbers of consecutive patients with coagulase-negative staphylococci were analyzed for comparison. The time to identification was significantly reduced post-PCR implementation (mean, 13.2 h; 95% confidence interval [95% CI], 10.5 to 15.9 h; P < 0.0001). However, the time to optimal antibiotic therapy was not significantly reduced. We conclude that implementation of a PCR assay demonstrated the potential to improve appropriate antibiotic use based on clinically meaningful and statistically significant reductions in the time to microbiologic identification. However, in order to realize this potential benefit, processes must be optimized and additional interventions initiated to facilitate providers' use of the PCR result.

Evaluation of the Nanosphere Verigene Gram-Positive Blood Culture Assay with the VersaTREK Blood Culture System and Assessment of Possible Impact on Selected Patients

“…However, this may be dependent on the method of communication with the provider. While Bauer et al (6) showed improvements in some of these areas with rapid notification of an infectious disease pharmacist in addition to the provider, Frye et al (4) showed no improvement in their outcome measures by releasing the results of a rapid molecular S. aureus/MRSA test into the electronic medical record, even though there was a statistically significant decrease in the time before results were available. Similarly, Carver et al showed that clinicians failed to utilize rapid mecA test results on positive blood cultures without the intervention of an infectious disease pharmacist (16).…”

Controlled Multicenter Evaluation of a Bacteriophage-Based Method for Rapid Detection of Staphylococcus aureus in Positive Blood Cultures

“…Furthermore, studies that analyzed rapid diagnostics used in combination with direct communication of results to the prescribing physician by the laboratory or an antimicrobial stewardship team have shown that communication is essential for affecting outcomes (30)(31)(32)(33)(34)(35). The results of this combination were shorter length of stay (30,32,35,36), shorter time to switch to a ␤-lactam antibiotic (30-32, 35, 36), and decreased mortality (35).…”

Assessment of Rapid-Blood-Culture-Identification Result Interpretation and Antibiotic Prescribing Practices

“…Poor standardization of reporting leads to variation in test result formatting between health care facilities, which may result in physician confusion, leading to inaction or inappropriate action. As exhibited in one study, introduction of a rapid PCR-based system for the identification of staphylococcal bloodstream infections reduced the time to organism identification, but there was no significant benefit to patient outcome or time to optimal antimicrobial therapy (6). Alternatively, rapid testing enables physicians to initiate pathogen-directed therapy in shortened time frames, provided the results are interpreted correctly.…”