Elizabeth Henderson

Methicillin-resistant Staphylococcus aureus in tertiary care institutions on the Canadian prairies 1990-1992.

OBJECTIVE To review experience with methicillin-resistant Staphylococcus aureus (MRSA) in tertiary acute-care teaching hospitals on the Canadian prairies. DESIGN Retrospective review for a 36-month period, 1990 through 1992. SETTING Five tertiary acute-care teaching hospitals in three Canadian prairie provinces. METHODS MRSA isolates and susceptibility were identified through the clinical microbiology laboratory at each institution. For each patient, data collected included duration of institutional residence prior to isolation, patient ethnic background, age, sex, and antimicrobial susceptibility. Epidemiologic typing of strains used restriction fragment length polymorphism analysis by pulsed-field gel electrophoresis. RESULTS Two hundred fifty-nine MRSA isolates were identified in 135 patients during the 36 months, with substantial institutional variation in number of isolates. No consistent increase in yearly numbers of isolates was apparent. Patients usually had MRSA identified at admission (62%); only one of five centers had the majority of isolates acquired nosocomially. Patients with MRSA present at admission were more frequently of aboriginal (First Nations) ethnicity (62% compared with 14% of nosocomial; P < 0.001). Pulsed-field gel electrophoresis of 167 isolates from 135 patients revealed 46 different strains with little interprovincial or interinstitutional identity of strains. CONCLUSIONS MRSA isolated in patients in tertiary care institutions in these three Canadian provinces usually is acquired prior to admission. A disproportionate number of isolates are identified in aboriginal Canadians. Epidemiologic typing was consistent with a polyclonal origin of MRSA in this geographic area.

High-Throughput Next-Generation Sequencing of Polioviruses

ABSTRACT The poliovirus (PV) is currently targeted for worldwide eradication and containment. Sanger-based sequencing of the viral protein 1 (VP1) capsid region is currently the standard method for PV surveillance. However, the whole-genome sequence is sometimes needed for higher resolution global surveillance. In this study, we optimized whole-genome sequencing protocols for poliovirus isolates and FTA cards using next-generation sequencing (NGS), aiming for high sequence coverage, efficiency, and throughput. We found that DNase treatment of poliovirus RNA followed by random reverse transcription (RT), amplification, and the use of the Nextera XT DNA library preparation kit produced significantly better results than other preparations. The average viral reads per total reads, a measurement of efficiency, was as high as 84.2% ± 15.6%. PV genomes covering >99 to 100% of the reference length were obtained and validated with Sanger sequencing. A total of 52 PV genomes were generated, multiplexing as many as 64 samples in a single Illumina MiSeq run. This high-throughput, sequence-independent NGS approach facilitated the detection of a diverse range of PVs, especially for those in vaccine-derived polioviruses (VDPV), circulating VDPV, or immunodeficiency-related VDPV. In contrast to results from previous studies on other viruses, our results showed that filtration and nuclease treatment did not discernibly increase the sequencing efficiency of PV isolates. However, DNase treatment after nucleic acid extraction to remove host DNA significantly improved the sequencing results. This NGS method has been successfully implemented to generate PV genomes for molecular epidemiology of the most recent PV isolates. Additionally, the ability to obtain full PV genomes from FTA cards will aid in facilitating global poliovirus surveillance.

Hospital ward design and prevention of hospital-acquired infections: A prospective clinical trial.

Several factors related to the hospital environment may affect the spread of hospital-acquired infections including ward design characteristics such as the number and location of handwashing stations and washrooms, and the number of beds per room. However, opportunities to study the effects of these factors are rare. The authors of this study conducted an analysis of the number of hospital-acquired infections in an older, ‘historic design’ hospital ward compared with a recently built ‘new design’ ward.

Prevalence of Antimicrobial Use in a Network of Canadian Hospitals in 2002 and 2009

The Canadian Nosocomial Infection Surveillance Program has been performing surveillance of antibiotic-resistant organisms in Canada since 1994. The authors of this study compared two point-prevalence surveys of antimicrobial use that were conducted in hospitals that were participating in the program in 2002 and 2009. The authors compared the use of antimicrobials between these two surveys. The changes in antimicrobial use over time are presented, in addition to potential reasons for and consequences of these changes.

How externalities impact an evaluation of strategies to prevent antimicrobial resistance in health care organizations

BackgroundThe rates of antimicrobial-resistant organisms (ARO) continue to increase for both hospitalized and community patients. Few resources have been allocated to reduce the spread of resistance on global, national and local levels, in part because the broader economic impact of antimicrobial resistance (i.e. the externality) is not fully considered when determining how much to invest to prevent AROs, including strategies to contain antimicrobial resistance, such as antimicrobial stewardship programs. To determine how best to measure and incorporate the impact of externalities associated with the antimicrobial resistance when making resource allocation decisions aimed to reduce antimicrobial resistance within healthcare facilities, we reviewed the literature to identify publications which 1) described the externalities of antimicrobial resistance, 2) described approaches to quantifying the externalities associated with antimicrobial resistance or 3) described macro-level policy options to consider the impact of externalities. Medline was reviewed to identify published studies up to September 2016.Main bodyAn externality is a cost or a benefit associated with one person’s activity that impacts others who did not choose to incur that cost or benefit. We did not identify a well-accepted method of accurately quantifying the externality associated with antimicrobial resistance. We did identify three main methods that have gained popularity to try to take into account the externalities of antimicrobial resistance, including regulation, charges or taxes on the use of antimicrobials, and the right to trade permits or licenses for antimicrobial use. To our knowledge, regulating use of antimicrobials is the only strategy currently being used by health care systems to reduce antimicrobial use, and thereby reduce AROs. To justify expenditures on programs that reduce AROs (i.e. to formally incorporate the impact of the negative externality of antimicrobial resistance associated with antimicrobial use), we propose an alternative approach that quantifies the externalities of antimicrobial use, combining the attributable cost of AROs with time-series analyses showing the relationship between antimicrobial utilization and incidence of AROs.ConclusionBased on the findings of this review, we propose a methodology that healthcare organizations can use to incorporate the impact of negative externalities when making resource allocation decisions on strategies to reduce AROs.

Reasons for testing women for genital Chlamydia trachomatis infection in the Calgary region

OBJECTIVE: To determine the clinical reason(s) for screening women with varying degrees of risk for genital Chlamydia trachomatis (CT) in the Calgary region. DESIGN: Women aged 15 to 75 years were enrolled at various patient care locations. Pertinent risk factors for genital CT infection were recorded and a gynecological examination was performed. Two endocervical swabs and a first-void urine sample were collected for CT detection using two different nucleic acid amplification test methods. SETTING: Calgary is an urban region that provides healthcare services to a population of almost one million people. Microbiology services are provided by Calgary Laboratory Services through a centralized regional laboratory service. MAIN RESULTS: 504 women with a mean age of 28.1 ± SD 8.22 years were enrolled. Two hundred ninety-one women (57.8%) were at high risk for acquiring genital CT infection. Twenty-eight (5.6%) tested positive for CT infection and almost all of these women (26 of 28, 93%) had risk factors for acquiring infection. Of the high-risk women, 9.8% were CT positive versus only 1.3% of women at low risk (P=0.0001). Only two of 152 (1.3%) women older than 30 years had genital CT infections. Although most women were asymptomatic, those with laboratory-confirmed CT infection were more likely to have genitourinary symptoms. Three hundred forty-three of 476 (72%) women who did not have genital CT infection had no risk factors, and screening was done as part of a routine gynecological examination for other purposes (prenatal visit, Pap smear). CONCLUSION: Women without risk factors are being screened routinely for genital CT infection as part of a routine gynecological examination done for other reasons. Elimination of the routine screening of low-risk women older than 30 years of age would decrease the current regional utilization of CT tests by as much as one-third.

Reasons for testing women for genital Chlamydia trachomatis infection in the Calgary region.

OBJECTIVE To determine the clinical reason(s) for screening women with varying degrees of risk for genital Chlamydia trachomatis (CT) in the Calgary region. DESIGN Women aged 15 to 75 years were enrolled at various patient care locations. Pertinent risk factors for genital CT infection were recorded and a gynecological examination was performed. Two endocervical swabs and a first-void urine sample were collected for CT detection using two different nucleic acid amplification test methods. SETTING Calgary is an urban region that provides healthcare services to a population of almost one million people. Microbiology services are provided by Calgary Laboratory Services through a centralized regional laboratory service. MAIN RESULTS 504 women with a mean age of 28.1 +/-SD 8.22 years were enrolled. Two hundred ninety-one women (57.8%) were at high risk for acquiring genital CT infection. Twenty-eight (5.6%) tested positive for CT infection and almost all of these women (26 of 28, 93%) had risk factors for acquiring infection. Of the high-risk women, 9.8% were CT positive versus only 1.3% of women at low risk (P=0.0001). Only two of 152 (1.3%) women older than 30 years had genital CT infections. Although most women were asymptomatic, those with laboratory-confirmed CT infection were more likely to have genitourinary symptoms. Three hundred forty-three of 476 (72%) women who did not have genital CT infection had no risk factors, and screening was done as part of a routine gynecological examination for other purposes (prenatal visit, Pap smear). CONCLUSION Women without risk factors are being screened routinely for genital CT infection as part of a routine gynecological examination done for other reasons. Elimination of the routine screening of low-risk women older than 30 years of age would decrease the current regional utilization of CT tests by as much as one-third.

The Validation of a Novel Surveillance System for Monitoring Bloodstream Infections in the Calgary Zone

Background. Electronic surveillance systems (ESSs) that utilize existing information in databases are more efficient than conventional infection surveillance methods. The objective was to assess an ESS for bloodstream infections (BSIs) in the Calgary Zone for its agreement with traditional medical record review. Methods. The ESS was developed by linking related data from regional laboratory and hospital administrative databases and using set definitions for excluding contaminants and duplicate isolates. Infections were classified as hospital-acquired (HA), healthcare-associated community-onset (HCA), or community-acquired (CA). A random sample of patients from the ESS was then compared with independent medical record review. Results. Among the 308 patients selected for comparative review, the ESS identified 318 episodes of BSI of which 130 (40.9%) were CA, 98 (30.8%) were HCA, and 90 (28.3%) were HA. Medical record review identified 313 episodes of which 136 (43.4%) were CA, 97 (30.9%) were HCA, and 80 (25.6%) were HA. Episodes of BSI were concordant in 304 (97%) cases. Overall, there was 85.5% agreement between ESS and medical record review for the classification of where BSIs were acquired (kappa = 0.78, 95% Confidence Interval: 0.75–0.80). Conclusion. This novel ESS identified and classified BSIs with a high degree of accuracy. This system requires additional linkages with other related databases.

Results from the Canadian Nosocomial Infection Surveillance Program for detection of carbapenemase-producing Acinetobacter spp. in Canadian hospitals, 2010–16

Objectives Globally there is an increased prevalence of carbapenem-resistant Acinetobacter spp. (CRAs) and carbapenemase-producing Acinetobacter spp. (CPAs) in the hospital setting. This increase prompted the Canadian Nosocomial Infection Surveillance Program (CNISP) to conduct surveillance of CRA colonizations and infections identified from patients in CNISP-participating hospitals between 2010 and 2016. Methods Participating acute care facilities across Canada submitted CRAs from 1 January 2010 to 31 December 2016. Patient data were collected from medical records using a standardized questionnaire. WGS was conducted on all CRAs and data underwent single nucleotide variant analysis, resistance gene detection and MLST. Results The 7 year incidence rate of CRA was 0.02 per 10 000 patient days and 0.015 per 1000 admissions, with no significant increase observed over the surveillance period (P > 0.73). Ninety-four CRA isolates were collected from 58 hospitals, of which 93 (98.9%) were CPA. Carbapenemase OXA-235 group (48.4%) was the most common due to two separate clusters, followed by the OXA-23 group (41.9%). Patients with a travel history were associated with 38.8% of CRA cases. The all-cause 30 day mortality rate for infected cases was 24.4 per 100 CRA cases. Colistin was the most active antimicrobial agent (95.8% susceptibility). Conclusions CRA remains uncommon in Canadian hospitals and the incidence did not increase from 2010 to 2016. Almost half of the cases were from two clusters harbouring OXA-235-group enzymes. Previous medical treatment during travel outside of Canada was common.

The cost of managing complex surgical site infections following primary hip and knee arthroplasty: A population-based cohort study in Alberta, Canada

OBJECTIVE Nearly 800,000 primary hip and knee arthroplasty procedures are performed annually in North America. Approximately 1% of these are complicated by a complex surgical site infection (SSI), leading to very high healthcare costs. However, population-based studies to properly estimate the economic burden are lacking. We aimed to address this knowledge gap. DESIGN Economic burden study. METHODS Using administrative health and clinical databases, we created a cohort of all patients in Alberta, Canada, who received a primary hip or knee arthroplasty between April 1, 2012, and March 31, 2015. All patients who developed a complex SSI postoperatively were identified through a provincial infection prevention and control database. A combination of corporate microcosting data and gross costing methods were used to determine total mean 12- and 24-month costs, enabling comparison of costs between the infected and noninfected patients. RESULTS Mean 12-month total costs were significantly greater in patients who developed a complex SSI compared to those who did not (CAD