Prevalence of USA300 colonization or infection and associated variables during an outbreak of community-associated methicillin-resistant Staphylococcus aureus in a marginalized urban population.

BACKGROUND: In 2004, an outbreak of the USA300 strain of methicillin-resistant Staphylococcus aureus (MRSA) was identified in persons with histories of homelessness, illicit drug use or incarceration in the Calgary Health Region (Calgary, Alberta). A prevalence study was conducted to test the hypotheses for factors associated with USA300 colonization or infection. METHODS: Participants were recruited at sites accessed by this marginalized population. Health care staff administered a questionnaire and collected crack pipes and nasal, axillary and skin infection swabs. Pipes and swabs were cultured according to standard techniques. MRSA isolates were further characterized by polymerase chain reaction (mecA, Panton-Valentine leukocidin and Staphylococcal cassette chromosome mec) and typing methods (pulsed-field gel electrophoresis, staphylococcal protein A typing and multilocus sequence typing). Colonization or infection was determined by having any one of nasal, axillary, skin infection or pipe swabs positive for USA300. Colonized participants had one or more nasal, axillary or pipe swab positive for USA300; infected participants had one or more skin infection swab positive for USA300. RESULTS: The prevalence of USA300 colonization or infection among 271 participants was 5.5% (range 3.1% to 9.0%). USA300 cases were more likely to report manipulation of skin infections (OR 9.55; 95% CI 2.74 to 33.26); use of crack pipes was not significant despite identification of the USA300 strain on two of four crack pipes tested. USA300 cases were more likely to report drug use between sex trade workers and clients (OR 5.86; 95% CI 1.63 to 21.00), and with casual sex partners (OR 5.40; 95% CI 1.64 to 17.78). CONCLUSION: Ongoing efforts to promote the appropriate treatment of skin infections in this population are warranted. The association of USA300 colonization or infection and drug use with sexual partners suggest a role for sexual transmission of the USA300 strain of MRSA.

Understanding influenza vaccination attitudes at a Canadian cancer center.

BACKGROUND: Although influenza vaccination benefits both health care workers and their patients, participation by staff in vaccination programs is disappointingly low. Understanding health care worker perceptions and needs is essential for improving rates of vaccination. METHODS: A self-administered questionnaire was distributed to all staff at a Canadian cancer center. Information was sought on previous frequency of participation in influenza vaccination, as well as motivations, perceptions, and preferences. RESULTS: Three hundred sixty-three (70%) of 515 cancer center staff members responded. Twenty-two percent of staff were vaccinated 4 or 5 times in the past 5 years and were primarily motivated by the desire to protect their own health (81%). Forty-nine percent participated 1 to 3 times in the past 5 years, and this group had diverse knowledge and vaccine-access needs. Twenty-nine percent received no vaccination in the previous 5 years because they believed the vaccine lacked efficacy (45%) or was harmful to health (19%). Moving from high to low levels of participation with influenza vaccination, the following trends were observed: increasing belief that vaccines cause illnesses or weaken the immune system, increasing belief that adverse effects of vaccination are underreported, and decreasing belief that vaccination programs are beneficial. CONCLUSIONS: Cancer center staff perceptions about influenza vaccination differ according to the past frequency of vaccine uptake. Strategies for promoting vaccination should be guided by these differences.

Infection rates in standard vs. hydrogel coated ventricular catheters.

BACKGROUND: Infection related to external ventricular drain (EVD) use is a common neurosurgical complication. Modified catheters with a hydrophilic surface may impede bacterial adherence and thereby reduce catheter related cerebrospinal fluid (CSF) infection. METHODS: A prospective randomized clinical trial compared the occurrence of CSF infection related to use of either standard silastic or hydrogel coated EVD catheters (Bioglide, Medtronic). Enrolment was available to all adult neurosurgery patients undergoing placement of a first EVD, at three university centers. The catheters were presoaked in a low concentration of bacitracin solution for 5-10 minutes prior to insertion. Bacterial infection was defined by heavy growth in a single CSF sample or light/medium growth in two consecutive samples. A secondary analysis was also conducted for "probable" CSF infection, including patients started on antibiotics after light/medium growth in a single CSF sample. Statistical analyses included Kaplan-Meier survival curve estimates accompanied by Log Rank and Breslow tests. RESULTS: There were 158 randomized patients available to assess for EVD related infection of CSF. The two study groups had similar clinical characteristics including average duration of EVD use (8 +/- 4 days). Definite CSF infection occurred in seven and probable infection in another six (8% total). Infection incidence rose steadily from day 2 (1%) to day 11 (11%). There was no difference of daily occurrence of EVD infection between the two catheter types. CONCLUSIONS: Infection remains a common hazard in the use of EVD, and we found no reduction of infection using the hydrogel-coated catheters when presoaked in low concentration bacitracin solution.