Kathryn N. Suh

Epidemiology and Outcome of Pneumonia Caused by Methicillin-Resistant Staphylococcus aureus (MRSA) in Canadian Hospitals

Background MRSA remains a leading cause of hospital-acquired (HAP) and healthcare-associated pneumonia (HCAP). We describe the epidemiology and outcome of MRSA pneumonia in Canadian hospitals, and identify factors contributing to mortality. Methods Prospective surveillance for MRSA pneumonia in adults was done for one year (2011) in 11 Canadian hospitals. Standard criteria for MRSA HAP, HCAP, ventilator-associated pneumonia (VAP), and community-acquired pneumonia (CAP) were used to identify cases. MRSA isolates underwent antimicrobial susceptibility testing, and were characterized by pulsed-field gel electrophoresis (PFGE) and Panton-Valentine leukocidin (PVL) gene detection. The primary outcome was all-cause mortality at 30 days. A multivariable analysis was done to examine the association between various host and microbial factors and mortality. Results A total of 161 patients with MRSA pneumonia were identified: 90 (56%) with HAP, 26 (16%) HCAP, and 45 (28%) CAP; 23 (14%) patients had VAP. The mean (± SD) incidence of MRSA HAP was 0.32 (± 0.26) per 10,000 patient-days, and of MRSA VAP was 0.30 (± 0.5) per 1,000 ventilator-days. The 30-day all-cause mortality was 28.0%. In multivariable analysis, variables associated with mortality were the presence of multiorgan failure (OR 8.1; 95% CI 2.5-26.0), and infection with an isolate with reduced susceptibility to vancomycin (OR 2.5, 95% CI 1.0-6.3). Conclusions MRSA pneumonia is associated with significant mortality. Severity of disease at presentation, and infection caused by an isolate with elevated MIC to vancomcyin are associated with increased mortality. Additional studies are required to better understand the impact of host and microbial variables on outcome.

Molecular characterization of moxifloxacin resistance from Canadian Clostridium difficile clinical isolates

Fluoroquinolone resistance in Clostridium difficile has been implicated in recent outbreaks of C. difficile infection. The purpose of this report was to characterize the molecular mechanism conferring resistance to moxifloxacin among C. difficile clinical isolates. Eighty-four C. difficile clinical isolates (collected as part of the Canadian Nosocomial Infection Surveillance Program) were evaluated in the current study. Pulsed-field gel electrophoresis was used to type the isolates. Susceptibility testing was performed using Clinical and Laboratory Standards Institute agar dilution methods. The quinolone resistance-determining region of both gyrA and gyrB was amplified using polymerase chain reaction and sequenced for each isolate. The proportion of isolates studied by the North American pulsed-field (NAP) type was as follows: NAP1 (47.6%), NAP2 (20.2%), NAP3 (5.9%), NAP4 (4.8%), NAP5 (2.4%), NAP6 (3.6%), and other patterns (15.5%). All isolates were resistant to ciprofloxacin. Among moxifloxacin-susceptible isolates (MIC < or =2 microg/mL), no amino acid substitutions were detected in either GyrA or GyrB. Three distinct amino acid substitutions were observed among the 3 isolates that had a moxifloxacin MIC of 8 microg/mL (GyrA Asp71 to Val, GyrB Asp426 to Asn, or Glu466 to Val). Isolates with a moxifloxacin MIC of 16 or 32 microg/mL (moderate-level resistance) all had a single identical amino acid substitution in GyrA (Thr82 to Ile). For isolates with a moxifloxacin MIC of > or =64 microg/mL (high-level resistance), this Thr82 to Ile substitution in GyrA was accompanied by at least 1 other amino acid substitution in either GyrA (Asp71 to Glu, Pro116 to Ala, or Ala118 to Ser) or GyrB (Ser366 to Ala, Asp426 to Asn, Asp426 to Val, or Leu444 to Phe) in all but 1 case. Moderate-level moxifloxacin resistance was associated with a single substitution in GyrA. High-level moxifloxacin resistance was associated with this GyrA substitution plus at least 1 other substitution in GyrA or GyrB.

Healthcare-Associated Influenza in Canadian Hospitals from 2006 to 2012

OBJECTIVE To determine trends, patient characteristics, and outcome of patients with healthcare-associated influenza in Canadian hospitals. DESIGN Prospective surveillance of laboratory-confirmed influenza among hospitalized adults was conducted from 2006 to 2012. Adults with positive test results at or after admission to the hospital were assessed. Influenza was considered to be healthcare associated if symptom onset was equal to or more than 96 hours after admission to a facility or if a patient was readmitted less than 96 hours after discharge or admitted less than 96 hours after transfer from another facility. Baseline characteristics of influenza patients were collected. Patients were reassessed at 30 days to determine the outcome. SETTING Acute care hospitals participating in the Canadian Nosocomial Infection Surveillance Program. RESULTS A total of 570 (17.3%) of 3,299 influenza cases were healthcare associated; 345 (60.5%) were acquired in a long-term care facility (LTCF), and 225 (39.5%) were acquired in an acute care facility (ACF). There was year-to-year variability in the rate and proportion of cases that were healthcare associated and variability in the proportion that were acquired in a LTCF versus an ACF. Patients with LTCF-associated cases were older, had a higher proportion of chronic heart disease, and were less likely to be immunocompromised compared with patients with ACF-associated cases; there was no significant difference in 30-day all-cause and influenza-specific mortality. CONCLUSIONS Healthcare-associated influenza is a major component of the burden of disease from influenza in hospitals, but the proportion of cases that are healthcare associated varies markedly from year to year, as does the proportion of healthcare-associated infections that are acquired in an ACF versus an LTCF.

Staphylococcus aureus bacteraemia of unknown primary source: Where do we stand?

There is no generally held definition of Staphylococcus aureus bacteraemia (SAB) of unknown source. For this paper, we consider it to occur when one or more positive blood cultures obtained from a patient grows S. aureus and the origin of the bacteraemia is uncertain after history, physical examination, chest radiography and any further investigations provoked by clinical findings. The incidence of SAB appears to be rising, particularly community-acquired (CA), but also hospital- or healthcare-acquired (HA). Major drivers appear to be intravenous drug use and increasing use of indwelling intravascular devices. There is an increasing prevalence of meticillin-resistant S. aureus (MRSA), both CA and HA. There is increasing hospital acquisition of MRSA that is phenotypically like CA strains, and there is increasing community-based treatment of HA infection. Metastatic infection is a risk of SAB. Infective endocarditis (IE) is a longstanding dreaded concern of SAB. Transoesophageal echocardiography appears to be a superior modality of recognising IE in the context of SAB and can guide the duration of therapy. Prosthetic joints and heart valves are at particular risk of haematogenous seeding from SAB. Implications of the rise of CA-MRSA in terms of metastatic infection warrant further study.

Understanding the burden of influenza infection among adults in Canadian hospitals: A comparison of the 2009-2010 pandemic season with the prepandemic and postpandemic seasons

BACKGROUND The degree to which the 2009-2010 influenza pandemic season differed from previous and subsequent influenza seasons in Canadian hospitals has not yet been assessed. METHODS Surveillance for laboratory-confirmed influenza among adults in 51 Canadian Nosocomial Infection Surveillance Program hospitals was conducted between November 1, 2006, and May 31, 2011. Inpatient characteristics, treatment, and outcomes of influenza cases in the pandemic season (2009-2010) were compared with those in the prepandemic (2006-2007 to 2008-2009) and postpandemic (2010-2011) seasons. RESULTS The incidence of influenza infection was lower in the postpandemic season (1.59/1,000 admissions) compared with the prepandemic seasons (2.00/1,000 admissions; P < .001) and the pandemic season (1.80/1,000 admissions; P < .001). The proportion of cases classified as health care-associated was much smaller during the pandemic season (6.6%) than in either the prepandemic season (23.2%; P < .001) or the postpandemic season (23.6%; P < .001). Inpatients in the pandemic season were significantly younger compared with those in the prepandemic and postpandemic seasons (P < .001). Inpatients in the pandemic season were less likely to have been vaccinated (P < .001), but more likely to be treated with antiviral agents (P < .001), than inpatients in both the prepandemic and postpandemic seasons. Intensive care unit admission was greater during the pandemic season, but there were no significant differences in 30-day mortality among the seasons. CONCLUSIONS Among adult inpatients, the pH1N1 pandemic season differed from seasonal influenza in terms of age, vaccination status, antiviral use, and intensive care unit admission, but not in terms of 30-day mortality.

Laboratory-Confirmed Pandemic H1N1 Influenza in Hospitalized Adults: Findings from the Canadian Nosocomial Infections Surveillance Program, 2009-2010

Surveillance for pandemic H1N1 influenza was conducted between June 1, 2009, and May 31, 2010, among adults at 40 participating hospitals in the Canadian Nosocomial Infection Surveillance Program. The first wave was characterized by a higher proportion of Aboriginals and pregnant women as well as severe outcomes, compared to the second wave.

Infection prevention and control practices related to Clostridium difficile infection in Canadian acute and long-term care institutions

BACKGROUND Clostridium difficile is an important pathogen in Canadian health care facilities, and infection prevention and control (IPC) practices are crucial to reducing C difficile infections (CDIs). We performed a cross-sectional study to identify CDI-related IPC practices in Canadian health care facilities. METHODS A survey assessing facility characteristics, CDI testing strategies, CDI contact precautions, and antimicrobial stewardship programs was sent to Canadian health care facilities in February 2005. RESULTS Responses were received from 943 (33%) facilities. Acute care facilities were more likely than long-term care (P < .001) and mixed care facilities (P = .03) to submit liquid stools from all patients for CDI testing. Physician orders were required before testing for CDI in 394 long-term care facilities (66%)-significantly higher than the proportions in acute care (41%; P < .001) and mixed care sites (49%; P < .001). A total of 841 sites (93%) had an infection control manual, 639 (76%) of which contained CDI-specific guidelines. Antimicrobial stewardship programs were reported by 40 (29%) acute care facilities; 19 (54%) of these sites reported full enforcement of the program. CONCLUSION Canadian health care facilities have widely varying C difficile IPC practices. Opportunities exist for facilities to take a more active role in IPC policy development and implementation, as well as antimicrobial stewardship.

Epidemiological features of influenza in Canadian adult intensive care unit patients

SUMMARY To identify predictive factors and mortality of patients with influenza admitted to intensive care units (ICU) we carried out a prospective cohort study of patients hospitalized with laboratory-confirmed influenza in adult ICUs in a network of Canadian hospitals between 2006 and 2012. There were 626 influenza-positive patients admitted to ICUs over the six influenza seasons, representing 17·9% of hospitalized influenza patients, 3·1/10 000 hospital admissions. Variability occurred in admission rate and proportion of hospital influenza patients who were admitted to ICUs (proportion range by year: 11·7–29·4%; 21·3% in the 2009–2010 pandemic). In logistic regression models ICU patients were younger during the pandemic and post-pandemic period, and more likely to be obese than hospital non-ICU patients. Influenza B accounted for 14·2% of all ICU cases and had a similar ICU admission rate as influenza A. Influenza-related mortality was 17·8% in ICU patients compared to 2·0% in non-ICU patients.

Estimating the volume of alcohol-based hand rub required for a hand hygiene program

BACKGROUND Providing alcohol-based hand rub (ABHR) at the point of care is a key success factor in enabling health care providers to achieve optimal hand hygiene practices. There are few tools available for health care organizations to assess the number of points of care, estimate the number of hand hygiene indications at each point of care, and estimate the anticipated volume of ABHR required to support a hand hygiene program. METHODS We developed an assessment tool to systematically evaluate the environmental hand hygiene needs in diverse care settings across a multisite health care organization. RESULTS We identified 1,103 points of care in 34 clinical units, of which only 53% had ABHR at point of care. There are an estimated 171,468,240 (95% confidence interval: 146,844,406-191,871,179) hand hygiene indications per year in our in-patient and emergency areas. If 100% compliance with hand hygiene is achieved, 240,056 L of ABHR will be required each year. CONCLUSIONS Our environmental assessment was invaluable in estimating the number of hand hygiene indications by unit and the logistical and financial requirements to implement a hand hygiene program. Other health care organizations may find this a useful framework to estimate their own environmental hand hygiene needs.

A New Approach to Improving Healthcare Personnel Influenza Immunization Programs: A Randomized Controlled Trial

Background Healthcare personnel influenza immunization rates remain sub-optimal. Following multiple studies and expert consultations, the “Successful Influenza Immunization Programs for Healthcare Personnel: A Guide for Program Planners” was produced. This trial assessed the impact of the Guide with facilitation in improving healthcare personnel influenza immunization rates in Canadian healthcare organizations. Methods A sample of 26 healthcare organizations across six Canadian provinces (ON, MB, NS, BC, SK, NL) was randomized to Intervention (n=13) or Control groups (n=13). Baseline influenza immunization rates were obtained for 2008–2009; the study groups were followed over two subsequent influenza seasons. The Intervention group received the Guide, facilitation support through workshops for managers and ongoing support. The Control groups conducted programs as usual. The Groups were compared using their reported influenza healthcare personnel influenza immunization rates and scores from a program assessment questionnaire. Findings Twenty-six organizations agreed to participate. 35% (9/26) of sites were acute care hospitals, 19% (5/26) continuing care, long-term care organizations or nursing homes, and 46% (12/26) were mixed acute care hospitals and long-term care or regional health authorities. The median rate of influenza immunization among healthcare personnel for the Intervention group was 43%, 44%, and 51% at three points in time respectively, and in the Control group: 62%, 57%, and 55% respectively. No significant differences were observed between the groups at the three points in time. However, there was a 7% increase in the median rates between the Baseline Year and Year Two in the Intervention group, and a 6% decrease in the Control group over the same time period, which was statistically significant (0.071 versus -0.058, p < 0.001). Interpretation This pragmatic randomized trial of the Guide with facilitation of its implementation improved healthcare personnel immunization rates, but these rates continued to be sub-optimal and below rates achievable in programs requiring personnel to be immunized. Trial Registration ClinicalTrials.gov NCT01207518