Background: Inadequate antibiotic therapy is a strong and independent predictor of poor outcomes in sepsis. Diagnostic uncertainty regarding the causative micro-organism is compensated for by liberal use of broad-spectrum antibiotics. As a result, resistance to antibiotics is an increasing public-health problem.
Study design: Prospective multicenter controlled observational study.
Setting: Three ICUs in Germany and France.
Synopsis: From 2005 to 2007, 63 patients were enrolled in the control group and 142 patients were enrolled in the sepsis group. In control patients, blood cultures and specimens were drawn daily at a maximum of three days after admission. In the sepsis group, blood samples were obtained on the day severe sepsis was suspected. Consecutive samples for the next two days after study inclusion were taken.
Taking BC as the laboratory comparison method, the sensitivity of PCR to detect culture-positive bacteremia in sepsis was 0.80 with a specificity of 0.77. PCR detected 29 of 41 microorganisms (70.3%) found in the BC. The highest recovery rate was observed for gram-negative bacteria (78.6%), fungi (50.0%), and gram-positive bacteria (47.6%). PCR from septic patients correlated well with markers of host response (IL-6 and PCT) and disease severity (SOFA score), even when the BC remained negative.
The appropriateness of antimicrobial therapy based on culture-based methods was not recorded, so it’s impossible to conclude whether or not the PCR would have contributed to a more effective therapy.
Bottom line: Concordance between BC and PCR is moderate in septic patients. PCR-based pathogen detection correlated with disease severity even if the BC remained negative, suggesting that the presence of microbial DNA in the bloodstream is a clinically significant event.
Citation: Bloos F, Hinder F, Becker K, et al. A multicenter trial to compare blood culture with polymerase chain reaction in severe human sepsis. Intensive Care Med. 2010;36(2):241-247.
Adding Rifampicin to Vancomycin Improves Outcomes in MRSA Pneumonia
Clinical question: Does adding rifampicin to vancomycin improve outcomes in patients with hospital-acquired MRSA pneumonia?
Background: Hospital-acquired MRSA pneumonia has a mortality of more than 20%. Vancomycin penetrates the lung tissue poorly. The value of adding rifampicin, an antibiotic with broad-spectrum coverage and good tissue penetration, was investigated.
Study design: Randomized open-label trial.
Setting: Medical ICU patients at Ulsan College of Medicine, Asan Medical Center, South Korea.
Synopsis: Patients older than 18 years of age with clinical symptoms suggestive of nosocomial pneumonia were randomized to receive vancomycin alone (V) or vancomycin plus rifampicin (VR). Clinicians could add additional antibiotics for gram-negative coverage as needed.