Comparison of PCR/electron spray ionization-time-of-flight-mass spectrometry versus traditional clinical microbiology for active surveillance of organisms contaminating high-use surfaces in a burn intensive care unit, an orthopedic ward and healthcare workers.

BACKGROUND: Understanding nosocomial pathogen transmission is restricted by culture limitations. Novel platforms, such as PCR-based electron spray ionization-time-of-flight-mass spectrometry (ESI-TOF-MS), may be useful as investigational tools. METHODS: Traditional clinical microbiology (TCM) and PCR/ESI-TOF-MS were used to recover and detect microorganisms from the hands and personal protective equipment of 10 burn intensive care unit (ICU) healthcare workers providing clinical care at a tertiary care military referral hospital. High-use environmental surfaces were assessed in 9 burn ICU and 10 orthopedic patient rooms. Clinical cultures during the study period were reviewed for pathogen comparison with investigational molecular diagnostic methods. RESULTS: From 158 samples, 142 organisms were identified by TCM and 718 by PCR/ESI-TOF-MS. The molecular diagnostic method detected more organisms (4.5 ± 2.1 vs. 0.9 ± 0.8, p < 0.01) from 99% vs. 67% of samples (p < 0.01). TCM detected S. aureus in 13 samples vs. 21 by PCR/ESI-TOF-MS. Gram-negative organisms were less commonly identified than gram-positive by both methods; especially by TCM. Among all detected bacterial species, similar percentages were typical nosocomial pathogens (18-19%) for TCM vs. PCR/ESI-TOF-MS. PCR/ESI-TOF-MS also detected mecA in 112 samples, vanA in 13, and KPC-3 in 2. MecA was associated (p < 0.01) with codetection of coagulase negative staphylococci but not S. aureus. No vanA was codetected with enterococci; one KPC-3 was detected without Klebsiella spp. CONCLUSIONS: In this pilot study, PCR/ESI-TOF-MS detected more organisms, especially gram-negatives, compared to TCM, but the current assay format is limited by the number of antibiotic resistance determinants it covers. Further large-scale assessments of PCR/ESI-TOF-MS for hospital surveillance are warranted.

A survey of invasive catheter practices in U.S. burn centers.

Burn-specific guidelines for optimal catheter rotation, catheter type, insertion methods, and catheter site care do not exist, and practices vary widely from one burn unit to another. The purpose of this study was to define current practices and identify areas of practice variation for future clinical investigation. An online survey was sent to the directors of 123 U.S. burn centers. The survey consisted of 23 questions related to specific practices in placement and maintenance of central venous catheters (CVCs), arterial catheters, and peripherally inserted central catheters (PICCs). The overall response rate was 36%; response rate from verified centers was 52%. Geographic representation was wide. CVC and arterial catheter replacement varied from every 3 days (24% of sites) to only for overt infection (24% of sites); 23% of sites did not use the femoral position for CVC placement. Nearly 60% of units used some kind of antiseptic catheter. Physicians inserted the majority of catheters, and 22% of sites used nonphysicians for at least some insertions. Ultrasound was routinely used by less than 50% of units. A wide variety of post-insertion dressing protocols were followed. PICCs were used in some critically injured patients in 37% of units; the majority of these users did not rotate PICCs. Thus, it can be surmised that wide practice variation exists among burn centers with regard to insertion and maintenance of invasive catheters. Areas with particular variability that would be appropriate targets of clinical investigation are line rotation protocols, catheter site care protocols, and use of PICCs in acute burns.