Community-associated methicillin-resistant Staphylococcus aureus (MRSA) is an increasingly common cause of skin and soft tissue infection (SSTI) worldwide. The prevalence of MRSA in SSTIs across Canada has not been well described. Studies in the United States have shown significant geographic variability in the prevalence of MRSA. This study characterizes the geographic prevalence and microbiology of MRSA in patients presenting to Canadian emergency departments with SSTIs.

Using a prospective, observational design, we enrolled patients with acute purulent SSTIs presenting to 17 hospital emergency departments and 2 community health centres (spanning 6 Canadian provinces) between July 1, 2008, and April 30, 2009. Eligible patients were those whose wound cultures grew S. aureus. MRSA isolates were characterized by antimicrobial susceptibility testing and pulsed-field gel electrophoresis. All patients were subjected to a structured chart audit, and patients whose wound swabs grew MRSA were contacted by telephone to gather detailed information regarding risk factors for MRSA infection, history of illness, and outcomes.

Of the 1,353 S. aureus–positive encounters recorded, 431 (32%) grew MRSA and 922 (68%) wounds grew methicillin-susceptible S. aureus. We observed significant variation in both the prevalence of MRSA (11–100%) and the proportion of community-associated strains of MRSA (0– 100%) across our study sites, with a significantly higher prevalence of MRSA in western Canada.

MRSA continues to emerge across Canada, and the prevalence of MRSA in SSTIs across Canada is variable and higher than previously expected.

To evaluate the impact of an emergency department (ED) automatic preauthorization policy on after-hours utilization of neuroradiology computed tomography (CT).

All CT studies of the head with contrast facial bones, orbits, spine, and neck requested through the ED and performed between January 1, 2004, and December 31, 2010, were reviewed. The preauthorization policy was instituted on February 25, 2008. A control group of noncontrast CT head studies was used for comparison. Pre- and postpolicy implementation utilization rates were compared between the control group of noncontrast CT head studies and the study group neuroradiology CT studies.

During the study period, 408,501 ED patient visits occurred and 20,703 neuroradiology CT studies were carried out. The pre- and postimplementation groups of noncontrast CT head scans totalled 7,474 and 6,094, respectively, whereas the pre- and postimplementation groups of all other neuroradiology CT studies totalled 3,833 and 3,302, respectively. The CT utilization between the two groups did not differ significantly: the noncontrast head group pre- and postpolicy implementation increased by 0.31 to 3.41%, whereas the utilization of all other neuroradiology CT studies increased by 0.22 to 1.84% (p value = 0.061 for a difference between groups).

Implementation of an automatic preauthorization policy for after-hours neuroradiology CT studies did not result in a statistically significant increase in CT utilization. This suggests that concerns regarding the negative effects of such policiesmay be unfounded, and further research in this area is warranted.

Many emergency physicians (EPs) order “confirmatory” abdominal computed tomography (CT) in young flank pain patients, despite a high clinical suspicion of renal colic and the risk of radiation exposure. We measured the adverse outcome rate among flank pain patients identified as not requiring abdominal CT by the EP on a data form, regardless of whether CT was eventually ordered. Our secondary objective was to describe diagnoses other than renal colic identified by CT in this population.

We conducted a prospective observational study at two community EDs. We asked staff EPs to complete a data sheet on patients ages 18 to 50 years with a first episode of flank pain, recording 1) if the flank pain was consistent with renal colic and 2) if the EP felt abdominal CT was indicated. Adverse outcomes (defined a priori as urgent surgical procedures, disability, or death) were assessed by research assistants at 4 weeks using telephone follow-up and a hospital records search.

We enrolled 389 patients; 353 completed follow-up (91%). The average age was 38.8 years, and 72.0% were male. Of 212 patients identified in the “CT not indicated” group, 2 had another diagnosis identified (unruptured diverticulitis and a ruptured ovarian cyst), but none had adverse outcomes (95% CI 0-1.4).

Adverse events were rare (< 1.5%) among patients < 50 years old with flank pain when CT was not required according to the clinical assessment of the EP. Future research should assess the adverse outcomes of withholding CT in low-risk patients using a larger patient sample.