Thompson, Rodney L.

The use of a differential quantitative blood culture technique (Isolator) to diagnose intravascular-device-related bacteremia (IDRB) was studied prospectively. During septic episodes in 44 patients, blood was obtained simultaneously through the suspected infected device and from a peripheral venipuncture. The blood samples were processed by the Isolator technique, which enables easy quantification of microorganisms. The cannula was removed, and its tip was cultured semiquantitatively. Of the 52 cannulas studied, 15 were the cause of IDRB, but only 7 of these showed a significantly higher bacterial count in blood obtained through the device compared with peripheral blood. The bacterial count was higher in blood drawn through the device than in peripheral blood in four of six cases that did not fulfill the definition of IDRB. Some blood cultures obtained through the device were positive despite negative cultures of peripheral blood and cannula tips (six cannulas). Quantitative blood cultures were not useful in diagnosing IDRB in this study.

ABSTRACT The epidemiologic relatedness of methicillin-resistant Staphylococcus aureus (MRSA) isolates is currently determined by analysis of chromosomal DNA restriction patterns by pulsed-field gel electrophoresis (PFGE). We have evaluated an alternative typing system (MicroSeq StaphTrack Kit; Perkin-Elmer Biosystems) based on the sequence analysis of the chromosomally encoded polymorphic repeat X region of the S. aureus protein A ( spa ) gene. A total of 69 clinical MRSA isolates were divided into 18 groups according to the number and nucleotide sequences of the spa repeats. Molecular typing results obtained both by spa sequencing and from the PFGE patterns were concordant except for one group, which contained 20 isolates recovered over a 2-year period from hospitalized patients at the Mayo Clinic. Although the spa typing patterns were indistinguishable for those isolates, PFGE analysis yielded seven related but distinguishable patterns. Further coagulase gene sequence analysis subtyped those 20 strains into four groups which followed distinct temporal and geographic distributions. During a 2-year epidemic period there were up to 7 fragment changes in PFGE patterns among epidemiologically related isolates, suggesting that PFGE may be unsuitable for long-term typing of strains involved in epidemics. Although more limited than PFGE in discriminatory power, spa sequencing analysis could be used as a screening method for typing of MRSA strains because of the shorter turnaround time, ease of use, and the inherent advantages of sequence analysis, storage, and sharing of information.

Background Surgical site infections (SSIs) are the leading cause of hospital-acquired infections and are associated with substantial health care costs, with increased morbidity and death. The Surgical Care Improvement Project (SCIP) contains standards that are nationally reported with the aim of improving patient outcomes after surgery. Our institution's standards for antimicrobial prophylaxis in the perioperative period are more stringent than these measures and may be considered “beyond SCIP.” The 4 elements of appropriate antimicrobial prophylaxis are timing, antibiotic selection, dosing, and intraoperative redosing. Objective To quantify antimicrobial SSI prophylaxis compliance in accordance with institutional standards and to identify potential opportunities for improvement. Methods Patients aged 18 years or older were included if they had an SSI between January 1, 2009, and June 30, 2010, according to the database maintained prospectively by the Infection Prevention and Control Unit. Adherence to our institution's practice standards was assessed through analysis of antibiotics administered—timing in relation to the incision, closure, and tourniquet inflation times for the procedure and antibiotic selection, dose, and redosing. Results Overall noncompliance with all 4 elements of antimicrobial prophylaxis was 75.4% among the 760 cases. Repeat dosing had the greatest noncompliance (45.1%); antibiotic selection had the lowest incidence of noncompliance (10.8%). Conclusions Noncompliance existed in each element of antimicrobial SSI prophylaxis, with antibiotic redosing leading in noncompliance. With the implementation of tools to assist the surgical team in following institutional standards, noncompliance will likely decline and additional research opportunities will exist.