In suspected bloodstream infections, accurate blood culture results are critical to timely diagnoses and appropriate antibiotic administration. An Initial Specimen Diversion Device®, Steripath® (Magnolia Medical Technologies, Seattle, WA, USA) was evaluated for efficacy in reducing blood culture contamination at Brooke Army Medical Center (6.8% six-month contamination rate prior to intervention) in a six-month quality improvement project. Blood cultures in the emergency department were collected using either Steripath or the standard method. Blood samples of 20 mL were cultured into an aerobic and anaerobic medium and incubated for five days using an automated microbial detection system immediately after collection. Positive bottles were Gram-stained and plated. Rapid molecular polymerase chain reaction identification was performed on all first positive bottles within a blood culture set for each admission or ED visit. Speciation was deduced during antimicrobial sensitivity testing using the Vitek-2 instrument. Seven out of 1016 (0.69%) contamination events occurred when using Steripath vs 53 out of 800 (6.6%) contamination events when using the standard method. Steripath use was associated with a 90% lower incidence of blood culture contamination vs the standard method. Post study, Steripath use was implemented as standard practice hospital-wide, and a retrospective data analysis attributed a 31.4% decrease in vancomycin days of therapy to Steripath adoption. Using Steripath significantly decreased blood culture contamination events for bacterial bloodstream infections compared to the standard method. Subsequent adoption of Steripath reduced overall vancomycin usage. With widescale implementation Steripath could bolster antibiotic stewardship, mitigating antibiotic resistance caused by unnecessary antibacterial treatments.
Background: Unambiguous clinical interpretation of PCR results for urinary tract infections (UTIs) remains a challenge. Here we compare and correlate multiplex qPCR results (quantification cycle values) with traditional microbial culture results (colony forming units) for clinical samples. Methods: Serial dilutions [108 to 100 colony forming units (CFU)/mL] were performed on five Gram-negative and two Gram-positive UTI-causing bacterial pathogens. For each dilution, quantitative cultures on solid media to confirm CFU/mL values and a real-time PCR UTI panel employing a nanofluidic Open ArrayTM platform producing quantification cycle (Cq) values were performed. Cq values were correlated with CFU/mL values, generating a semi-quantitative interpretive scale for clinical samples. The clinical utility of the scale was then assessed using PCR and culture data from 168 clinical urine samples. Results: For Gram-negative bacteria, Cq values of 28 corresponded with ≥105 CFU/mL, <105 CFU/mL and negative cultures, respectively. For Gram-positive bacteria, Cq values of 30 corresponded with ≥105 CFU/mL, <105 CFU/mL and negative cultures, respectively. Among 168 urine specimens (including 138 Gram-negative and 30 Gram-positive bacteria), there was 83.3% agreement (n = 140/168) and 16.6% non-agreement (n = 28/168) between culture CFU/mL and qPCR Cq. Gram-negative bacteria had higher agreement (87.6%, 121/138) than Gram-positive bacteria (63.3%, 19/30). Conclusions: This study demonstrates that qPCR Cq results can be directly correlated with traditional urine quantitative culture results and reliably identify the clinically relevant cutoff of 105 CFU/mL for detected uropathogens.