Community-based educational intervention to limit the dissemination of community-associated methicillin-resistant Staphylococcus aureus in Northern Saskatchewan, Canada.

BACKGROUND: Surveillance examining the incidence of community-associated methicillin-resistant Staphylococcus aureus (CA-MRSA) was conducted over 8 years beginning in 2001 in three health regions covering the northern half of Saskatchewan. The annual rate of individuals reported with CA-MRSA infection in these regions dramatically increased from 8.2 per 10,000 population in 2001 (range to 4.4-10.1 per 10,000) to 168.1 per 10,000 in 2006 (range 43.4-230.9 per 10,000). To address this issue, a team of community members, healthcare professionals, educators and research scientists formed a team called "the Northern Antibiotic Resistance Partnership" (NARP) to develop physician, patient, community, and school based educational materials in an attempt to limit the spread of CA-MRSA. METHODS: Posters, radio broadcasts, community slide presentations, physician treatment algorithms, patient pamphlets, and school educational programs Do Bugs Need Drugs http://www.dobugsneeddrugs.org and Germs Away http://www.germsaway.ca were provided to targeted northern communities experiencing high rates of infections. RESULTS: Following implementation of this program, the rates of MRSA infections in the targeted communities have decreased nearly two-fold (242.8 to 129.3 infections/10,000 population) from 2006 to 2008. Through pre-and post-educational intervention surveys, this decrease in MRSA infections coincided with an increase in knowledge related to appropriate antimicrobial usage and hand washing in these communities. CONCLUSION: These educational materials are all freely available http://www.narp.ca and will hopefully aid in increasing awareness of the importance of proper antimicrobial usage and hygiene in diminishing the spread of S. aureus and other infectious diseases in other communities.

ampC gene expression in promoter mutants of cefoxitin-resistant Escherichia coli clinical isolates.

Reverse transcriptase polymerase chain reaction was used to determine the amount of overexpression of the ampC gene in 52 cefoxitin-resistant Escherichia coli clinical isolates that had previously characterized mutations in their ampC promoter/attenuator regions. The results showed that mutations that create a consensus -35 box (TTGACA) are the most important factor in strengthening the ampC promoter, followed by base pair insertions that increase the distance between the -35 and -10 boxes to 17 or 18 bp. Mutations in the -10 box are of lesser importance and those in the attenuator region appear to have little effect on ampC expression. Three strains overexpress ampC due to the effect of insertion elements located in the ampC promoter regions. Further, the data show that there is no correlation between ampC overexpression and the minimum inhibition concentration of cefoxitin in clinical isolates. Overall, the data indicate that a combination of ampC promoter mutations and other strain-specific factors combine to contribute to the magnitude of cefoxitin resistance in E. coli.

Cluster of cases of severe acute respiratory syndrome among Toronto healthcare workers after implementation of infection control precautions: a case series.

OBJECTIVE: To review the severe acute respiratory syndrome (SARS) infection control practices, the types of exposure to patients with SARS, and the activities associated with treatment of such patients among healthcare workers (HCWs) who developed SARS in Toronto, Canada, after SARS-specific infection control precautions had been implemented. METHODS: A retrospective review of work logs and patient assignments, detailed review of medical records of patients with SARS, and comprehensive telephone-based interviews of HCWs who met the case definition for SARS after implementation of infection control precautions. RESULTS: Seventeen HCWs from 6 hospitals developed disease that met the case definition for SARS after implementation of infection control precautions. These HCWs had a mean age (+/-SD) of 39+/-2.3 years. Two HCWs were not interviewed because of illness. Of the remaining 15, only 9 (60%) reported that they had received formal infection control training. Thirteen HCWs (87%) were unsure of proper order in which personal protective equipment should be donned and doffed. Six HCWs (40%) reused items (eg, stethoscopes, goggles, and cleaning equipment) elsewhere on the ward after initial use in a room in which a patient with SARS was staying. Use of masks, gowns, gloves, and eyewear was inconsistent among HCWs. Eight (54%) reported that they were aware of a breach in infection control precautions. HCWs reported fatigue due to an increased number and length of shifts; participants worked a median of 10 shifts during the 10 days before onset of symptoms. Seven HCWs were involved in the intubation of a patient with SARS. One HCW died, and the remaining 16 recovered. CONCLUSION: Multiple factors were likely responsible for SARS in these HCWs, including the performance of high-risk patient care procedures, inconsistent use of personal protective equipment, fatigue, and lack of adequate infection control training.

Methicillin-resistant Staphylococcus aureus in Canadian aboriginal people.

We describe 279 hospitalized Canadian aboriginals in whom methicillin-resistant Staphylococcus aureus (MRSA) was detected. They were identified in 38 Canadian hospitals from 1995 through 2002. Compared with nonaboriginals, aboriginals were more likely to be younger than 18 years of age (OR, 1.8; P<.0001), to have had an MRSA infection (OR, 3.8; P<.0001), and to have had MRSA isolated from specimens of skin or soft tissue (OR, 4.1; P=.016). The clinical features of MRSA infection in aboriginals are distinct from those in the general patient population with MRSA infection in Canadian hospitals, and the genetic background of MRSA isolates from aboriginals also varies from that of strains from the non-aboriginal population.

Central venous catheter-associated bloodstream infections occurring in Canadian intensive care units: A six-month cohort study.

OBJECTIVE: To determine the rate and risk factors associated with central venous catheter (CVC)-associated bloodstream infections (BSIs) in Canadian intensive care units (ICUs). DESIGN: A prospective, active six-month cohort with a nested case-control study. SETTING: Forty-one ICUs located in 19 Canadian hospitals. METHODS: Data were collected using a standardized format on all CVCs and patients when a CVC was inserted for more than 48 h. Results of microbiological studies and therapeutic interventions were recorded when a BSI occurred. RESULTS: There were 182 BSIs from 3696 CVC insertions in 2531 patients. Coagulase-negative staphylococci were responsible for 73% of the BSIs. Mean rates of CVC-associated BSIs per 1000 CVC days were 6.9, 6.8 and 5.0 in adult, neonatal and pediatric ICUs, respectively. Significant factors associated with BSI included duration of CVC insertion (OR=1.2, 95% CI 1.1 to 1.3), receiving total parenteral nutrition (OR=4.1, 95% CI 1.2 to 14.3) and having one or more CVCs (OR=3.1, 95% CI 1.5 to 6.5). In the case-control study, 80% of the variance in a backward elimination logistic regression analysis was explained by duration of CVC insertion (OR=1.2 per day), receiving chemotherapy (OR=6.1), more than one CVC insertion during the study (OR=3.5), insertion of a CVC with two or more lumens (OR=2.3), using the CVC to administer total parenteral nutrition (OR=1.6) and having a surgical wound other than a clean wound (OR=1.6). CONCLUSION: The present study identified risk factors explaining 80% of the variance associated with BSIs and is one of the largest reports on the rate of CVC-associated BSIs occurring in the ICU setting.

Clinical and epidemiologic features of methicillin-resistant Staphylococcus aureus in elderly hospitalized patients.

We describe characteristics of elderly patients with MRSA identified in 37 Canadian hospitals between 1995 and 2002. Of these inpatients, 6,613 (66%) were older than 65 years. They were more likely than younger patients to have been colonized without infection and to have had MRSA isolated from urine or the perineum. The epidemiology and clinical features of these patients is distinct from that of younger patients.

Prospective surveillance for primary bloodstream infections occurring in Canadian hemodialysis units.

OBJECTIVE: Bloodstream infections are a major cause of morbidity and mortality in patients receiving long-term hemodialysis. We wanted to determine the incidence of hemodialysis-related bloodstream infections in Canadian centers participating in the Canadian Nosocomial Infection Surveillance Program. METHODS: Prospective surveillance for hemodialysis-related bloodstream infections was performed in 11 centers during a 6-month period. Bloodstream infections were defined by published criteria. Hemodialysis denominators included the number of dialysis procedures, the number of patient-days on dialysis, and the frequencies of different types of vascular access. RESULTS: There were 184 bloodstream infections in 133,158 dialysis procedures (1.4 per 1,000) and 316,953 patient-days (0.6 per 1,000). Hemodialysis access through arteriovenous (AV) fistulae was associated with the lowest risk for bloodstream infection (0.2 per 1,000 dialysis procedures). The relative risk for infection was 2.5 with AV graft access, 15.5 with cuffed and tunneled central venous catheter (CVC) access, and 22.5 with uncuffed CVC access (P < .001). There was marked variation among the 11 centers in the means of vascular access used for hemodialysis. Significant variation in infection rates was observed among the centers when controlling for types of access. CONCLUSIONS: There was a hierarchy of risk of hemodialysis-related bloodstream infection according to type of vascular access. There was significant variation in the type of vascular access being used among the Canadian hemodialysis centers, and also variation in access-specific infection rates between centers.

The state of infection surveillance and control in Canadian acute care hospitals.

BACKGROUND: Nosocomial infections and antibiotic-resistant pathogens cause significant morbidity, mortality, and economic costs. The infection surveillance and control resources and activities in Canadian acute care hospitals had not been assessed in 20 years. METHODS: In 2000, surveys were mailed to infection control programs in all Canadian hospitals with more than 80 acute care beds. The survey was modeled after the US Study on the Efficacy of Nosocomial Infection Control instrument, with new items dealing with resistant pathogens and computerization. Surveillance and control indices were calculated. RESULTS: One hundred seventy-two of 238 (72.3%) hospitals responded. In 42.1% of hospitals, there was fewer than 1 infection control practitioner per 250 beds. Just 60% of infection control programs had physicians or doctoral professionals with infection control training who provided services. The median surveillance index was 65.6/100, and the median control index was 60.5/100. Surgical site infection rates were reported to individual surgeons in only 36.8% of hospitals. CONCLUSIONS: There were deficits in the identified components of effective infection control programs. Greater investment in resources is needed to meet recommended standards and thereby reduce morbidity, mortality, and expense associated with nosocomial infections and antibiotic-resistant pathogens.

Incidence of bloodstream infection in multicenter inception cohorts of hemodialysis patients.

OBJECTIVE: To assess incidence of and identify risk factors for bloodstream infection in patients starting hemodialysis or starting a new means of vascular access for hemodialysis. METHOD: Two cohorts of patients, 1 initiating hemodialysis (new patients) and a 1:1 matching group of patients continuing hemodialysis but starting a new vascular access (continuing patients), were enrolled from 9 Canadian hemodialysis units and followed for 6 months. Bloodstream infection was defined using established criteria. A nested case-control study was carried out, using as cases those cohort patients diagnosed with infection. Each case was matched with a control having the same means of access and new or continuing status. RESULTS: A total of 527 patients (258 new, 269 continuing), were recruited and underwent 31,268 hemodialysis procedures during this 6-month follow-up. There were 96 bloodstream infections in 93 patients (11.97/10,000 days, 28.81/10,000 hemodialysis procedures), yielding a relative risk of infection of 3.33 (95% CI, 2.12-5.24) for patients with a previous bloodstream infection and 1.56 (95% CI, 1.02-2.38) for patients continuing hemodialysis by a new means of access. Survival analysis revealed that compared to arteriovenous fistula vascular access, the relative risk of bloodstream infection in patients was 1.47 (95% CI, 0.36-5.96) for arteriovenous grafts, 8.49 (95% CI, 3.03-23.78) for cuffed central venous catheters, and 9.87 (95% CI, 3.46-28.20) for uncuffed central venous catheters. The regression model of the case-control study identified earlier bloodstream infection (OR, 6.58), poor patient hygiene (OR, 3.48), and superficial access-site infection (OR, 4.36) as additional risk factors. CONCLUSION: During the first 6 months there is a high rate of bloodstream infection in patients starting hemodialysis either for the first time or by a new means of vascular access. Previous hemodialysis bloodstream infection and continuing hemodialysis by a new means of vascular access are markers for an increased risk of infection, as is poor patient hygiene. Central venous catheter vascular access, whether cuffed or uncuffed, has a much higher infection risk. In this study, there was no difference in infection rate between cuffed and uncuffed central catheters.

Risk factors for SARS transmission from patients requiring intubation: a multicentre investigation in Toronto, Canada.

BACKGROUND: In the 2003 Toronto SARS outbreak, SARS-CoV was transmitted in hospitals despite adherence to infection control procedures. Considerable controversy resulted regarding which procedures and behaviours were associated with the greatest risk of SARS-CoV transmission. METHODS: A retrospective cohort study was conducted to identify risk factors for transmission of SARS-CoV during intubation from laboratory confirmed SARS patients to HCWs involved in their care. All SARS patients requiring intubation during the Toronto outbreak were identified. All HCWs who provided care to intubated SARS patients during treatment or transportation and who entered a patient room or had direct patient contact from 24 hours before to 4 hours after intubation were eligible for this study. Data was collected on patients by chart review and on HCWs by interviewer-administered questionnaire. Generalized estimating equation (GEE) logistic regression models and classification and regression trees (CART) were used to identify risk factors for SARS transmission. RESULTS: 45 laboratory-confirmed intubated SARS patients were identified. Of the 697 HCWs involved in their care, 624 (90%) participated in the study. SARS-CoV was transmitted to 26 HCWs from 7 patients; 21 HCWs were infected by 3 patients. In multivariate GEE logistic regression models, presence in the room during fiberoptic intubation (OR = 2.79, p = .004) or ECG (OR = 3.52, p = .002), unprotected eye contact with secretions (OR = 7.34, p = .001), patient APACHE II score > or = 20 (OR = 17.05, p = .009) and patient Pa0(2)/Fi0(2) ratio < or = 59 (OR = 8.65, p = .001) were associated with increased risk of transmission of SARS-CoV. In CART analyses, the four covariates which explained the greatest amount of variation in SARS-CoV transmission were covariates representing individual patients. CONCLUSION: Close contact with the airway of severely ill patients and failure of infection control practices to prevent exposure to respiratory secretions were associated with transmission of SARS-CoV. Rates of transmission of SARS-CoV varied widely among patients.

Acinetobacter baumannii in casualties returning from Afghanistan.

Military personnel returning from Afghanistan and entering Canadian hospitals may be infected with multidrug resistant Acinetobacter baumannii. The Public Health Agency of Canada, in conjunction with the Canadian Forces, have developed an alert to inform hospitals of the potential for importation of Acinetobacter baumannii, and the appropriate precautionary measures that should be taken to prevent secondary spread within hospitals.

Hepatitis C virus infection among First Nation and non-First Nation people in Manitoba, Canada: a public health laboratory study.

Demographic information and laboratory test results on 136 169 clinical serum specimens submitted to the public health laboratory in Manitoba, Canada, for hepatitis C virus (HCV) testing between January 1995 and December 2003 were analyzed. The difference in the clearance rates of HCV infection, without therapeutic intervention, and the HCV genotypes infecting First Nation and non-First Nation people were studied. The rates of co-infection of HCV-positive individuals with other hepatitis viruses were also compared between the two study groups. The results of the analyses of the data indicated that there was a 4.4-fold increase in the number of specimens tested and a 4.9-fold decrease in HCV antibody (anti-HCV) positive cases during the study period. The proportion of specimens submitted for testing from First Nation individuals was lower than their proportion in the Manitoba population. Our study also indicated that there was a significantly higher proportion of First Nation patients who had self-limiting infection (patients cleared the infection and became HCV RNA negative without anti-HCV treatment) in comparison to non-First Nation patients. The proportion of First Nation females who had self-limiting infection was significantly higher than non-First Nation females. HCV genotype 1 infection represented more than 60% of HCV infection in Manitoba. The rate of individuals positive for the hepatitis A virus antibody in the HCV-positive population was higher among First Nation than non-First Nation individuals. On the other hand, there were more HCV-infected First Nation patients than non-First Nation patients who were not immune to the hepatitis B virus. The data indicate that fewer First Nation patients seek anti-HCV therapy in comparison to non-First Nation. In conclusion, the differences in the rates of HCV self-limiting infection between First Nation and non-First Nation individuals in Manitoba may reflect the genetic differences between the two cohorts, which may consequently affect the immune response to the HCV infection.

Enhanced surveillance of newly acquired hepatitis C virus infection in Canada, 1998 to 2004.

The purpose of this study was to determine trends in disease incidence and recent patterns of hepatitis C virus (HCV) transmission in Canada, using the Enhanced Hepatitis Strain Surveillance System (EHSSS). Demographic, clinical, and potential risk factor information on newly acquired HCV infection, from 1998 to 2004, was collected using standardized questionnaires. During this time period, the reported incidence of newly acquired HCV infection declined by 36.4% from 3.3 cases per 100,000 in 1998, to 2.1 cases per 100,000 in 2004. The disease incidence peaked at 15 to 39 y of age, confirming injecting drug use as the most frequently reported route of transmission. The proportion of cases attributed to health care-acquired HCV infection decreased over this time period. Although the incidence of newly acquired HCV infection in the EHSSS was found to be declining, hepatitis C remains an important public health threat to Canadians. Prevention efforts for HCV should focus on injection drug use, especially for people aged 15 to 39 y.

Molecular characterization of cefoxitin-resistant Escherichia coli from Canadian hospitals.

A study designed to gain baseline information on strains of Escherichia coli displaying resistance to cefoxitin in Canada is described. A total of 29,323 E. coli isolates were screened at 12 participating hospital sites as part of an extended-spectrum beta-lactamase surveillance initiative. A total of 411 clinically significant, nonrepeat isolates displaying reduced susceptibilities to the NCCLS-recommended beta-lactams were submitted to a central laboratory over a 1-year period ending on 30 September 2000. Two hundred thirty-two isolates were identified as resistant to cefoxitin. All cefoxitin-resistant strains were subtyped by pulsed-field gel electrophoresis, and of these, 182 strains revealed a unique fingerprint and 1 strain was untypeable. PCR and sequence analysis of the ampC promoter region revealed 51 different promoter or attenuator variants and 14 wild-type promoters. Three promoter regions were interrupted by insertion elements, two contained IS10 elements, and one contained an IS911 variant. PCR and sequence analysis for the detection of acquired AmpC resistance (by the acquisition of ACT-1/MIR-1, CMY-2, or FOX) revealed that 25 strains contained CMY-2, including 7 of the strains found to have wild-type promoters. The considerable genetic variability in both the strain fingerprint and the promoter region suggests that AmpC-type resistance may emerge spontaneously by mutation of sensitive strains rather than by the spread of strains or plasmids in the hospital setting.

Detection of airborne severe acute respiratory syndrome (SARS) coronavirus and environmental contamination in SARS outbreak units.

Severe acute respiratory syndrome (SARS) is characterized by a risk of nosocomial transmission; however, the risk of airborne transmission of SARS is unknown. During the Toronto outbreaks of SARS, we investigated environmental contamination in SARS units, by employing novel air sampling and conventional surface swabbing. Two polymerase chain reaction (PCR)-positive air samples were obtained from a room occupied by a patient with SARS, indicating the presence of the virus in the air of the room. In addition, several PCR-positive swab samples were recovered from frequently touched surfaces in rooms occupied by patients with SARS (a bed table and a television remote control) and in a nurses' station used by staff (a medication refrigerator door). These data provide the first experimental confirmation of viral aerosol generation by a patient with SARS, indicating the possibility of airborne droplet transmission, which emphasizes the need for adequate respiratory protection, as well as for strict surface hygiene practices.

Laboratory characterization of methicillin-resistant Staphylococcus aureus in Canadian hospitals: results of 5 years of National Surveillance, 1995-1999.

Two thousand seven hundred eighty single-patient, methicillin-resistant Staphylococcus aureus (MRSA) isolates collected between January 1995 and December 1999 at 17 tertiary care hospital sites across Canada were characterized by phenotypic and genotypic techniques. Six clonal types, as defined by pulsed-field gel electrophoresis, comprised 87% of all isolates and were labeled Canadian (C) MRSA-1 through -6. CMRSA-1 was the most prevalent clonal type, representing 45% of all MRSA. CMRSA-2 was indistinguishable from the New York clone and was more likely to be associated with community acquisition. CMRSA-3 was more likely to cause an infection, compared with the other CMRSA types. CMRSA-4 was indistinguishable from epidemic (E) MRSA-16 from the United Kingdom. Both CMRSA-5 and -6 occurred primarily in single-site, multiyear outbreaks. This study confirms that the epidemiology of MRSA in Canada is evolving, but most isolates at this time appear to belong to one of a small number of epidemic clones.

Ambler class A extended-spectrum beta-lactamase-producing Escherichia coli and Klebsiella spp. in Canadian hospitals.

This report describes a study carried out to gain baseline information on the molecular characteristics of extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli and Klebsiella spp. in Canada. A total of 29,323 E. coli and 5,156 Klebsiella sp. isolates were screened at 12 participating sites. Of these, 505 clinically significant, nonrepeat isolates displaying reduced susceptibility to the NCCLS-recommended beta-lactams were submitted to a central laboratory over a 1-year period ending on 30 September 2000. A total of 116 isolates were confirmed to be ESBL producers. PCR and sequence analysis revealed the presence of TEM-11 (n = 1), TEM-12 (n = 1), TEM-29 (n = 1), TEM-52 (n = 4), CTX-M-13 (n = 1), CTX-M-14 (n = 15), CTX-M-15 (n = 11), SHV-2 (n = 2), SHV-2a (n = 12), SHV-5 (n = 6), SHV-12 (n = 45), and SHV-30 (n = 2). Five novel beta-lactamases were identified and designated TEM-115 (n = 2), TEM-120 (n = 1), SHV-40 (n = 2), SHV-41 (n = 4), and SHV-42 (n = 1). In addition, no molecular mechanism was identified for five isolates displaying an ESBL phenotype. Macrorestriction analysis of all ESBL isolates was conducted, as was restriction fragment length polymorphism analysis of plasmids harboring ESBLs. Although a "clonal" distribution of isolates was observed at some individual sites, there was very little evidence suggesting intrahospital spread. In addition, examples of identical or closely related plasmids that were identified at geographically distinct sites across Canada are given. However, there was considerable diversity with respect to plasmid types observed.