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 CPA 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.

BACKGROUND:Health care-associated infections are a common cause of patient morbidity and mortality. We sought to describe the trends in these infections in acute care hospitals, using data from 3 national point-prevalence surveys.METHODS:The Canadian Nosocomial Infection Surveillance Program (CNISP) conducted descriptive point-prevalence surveys to assess the burden of health care-associated infections on a single day in February of 2002, 2009 and 2017. Surveyed infections included urinary tract infection, pneumonia, Clostridioides difficile infection, infection at surgical sites and bloodstream infections. We compared the prevalence of infection across the survey years and considered the contribution of antimicrobial-resistant organisms as a cause of these infections.RESULTS:We surveyed 28 of 33 (response rate 84.8%) CNISP hospitals (6747 patients) in 2002, 39 of 55 (response rate 71.0%) hospitals (8902 patients) in 2009 and 47 of 66 (response rate 71.2%) hospitals (9929 patients) in 2017. The prevalence of patients with at least 1 health care-associated infection increased from 9.9% in 2002 (95% confidence interval [CI] 8.4%-11.5%) to 11.3% in 2009 (95% CI 9.4%-13.5%), and then declined to 7.9% in 2017 (95% CI 6.8%-9.0%). In 2017, device-associated infections accounted for 35.6% of all health care-associated infections. Methicillin-resistant Staphylococcus aureus (MRSA) accounted for 3.9% of all organisms identified from 2002 to 2017; other antibiotic-resistant organisms were uncommon causes of infection for all survey years.INTERPRETATION:In CNISP hospitals, there was a decline in the prevalence of health care-associated infection in 2017 compared with previous surveys. However, strategies to prevent infections associated with medical devices should be developed. Apart from MRSA, few infections were caused by antibiotic-resistant organisms.

Background Healthcare acquired infections (HAI) are an important public health problem in developed countries, but comprehensive data on trends over time are lacking. Prevalence surveys have been used as a surrogate for incidence studies and can be readily repeated. Methods The Canadian Nosocomial Infection Surveillance Program conducted prevalence surveys in 2002 and 2009 in a large network of major Canadian acute care hospitals. NHSN definitions of HAI were used. Use of isolation precautions on the survey day was documented. Results In 2009, 9,953 acute care inpatients were surveyed; 1,234 infections (124/1000) were found, compared to 111/1000 in 2002, ( p < 0.0001). There was increased prevalence of urinary tract infection (UTI) and Clostridium difficile , offset by decreases in pneumonia and bloodstream infection. Use of isolation precautions increased from 77 to 148 per 1000 patients ( p < 0.0001), attributable to increased use of contact precautions in patients infected or colonized with antimicrobial resistant organisms. Conclusion Between 2002 and 2009 HAI prevalence increased by 11.7 % in a network of major Canadian hospitals due to increases in Clostridium difficile and urinary tract infection. The use of isolation precautions increased by 92.2 % attributable to increased contact isolation. National prevalence surveys are useful tools to assess evolving trends in HAI.

Sepsis has seen an incremental increase in cases of about 13% annually in the USA and accounts for approximately 4400 deaths among pediatric patients. Early identification of the specific pathogen allows the clinician to ensure that the antibiotic coverage is optimal, an intervention that has been shown to improve patient outcomes in sepsis. Our study's objective was to assess the impact of a rapid Bruker MALDI-T of identification protocol on pediatric sepsis cases by assessing various indicators. We assessed the quality of care by measuring the following indicators; time to identification of the pathogen, initiation of the most appropriate antibiotic, length of stay (LOS) in hospital and patient outcomes, using a retrospective review over three consecutive years. In total 92 pediatric patients, similar in age and gender distributions were assessed; 37 in 2012, 33 in 2013 and 22 in 2014. The introduction of MALDI-TOF identification in 2013 led to a significant decrease in time to identify a pathogen by 21.03 hours (p = 1.95E-05). A short incubation MALDI-TOF identification protocol in 2014 further reduced time to identification by 17.75 hours (p = 2.48E-3). Overall in 2014 this led to a trend to earlier optimization of antibiotics by 20.2 hours (p = 0.14) and a reduction in length of stay after the implementation of MALDI-ToF identification in 2013 of 3.07 days and a further reduction of 8.92 days after the introduction of the rapid short incubation identification protocol using MALDI-Tof in 2014 (P = 0.12). By evaluating the subgroup of patients where antibiotics were changed, our study confirmed that patients received appropriate therapy 48.8% (20.2 hours) earlier compared to conventional methods leading to a decrease in length of stay of 23.65 days after the implementation of MALDI-ToF identification and a further reduction of 9.82 days in 2014 compared to 2012 (p = 0.02). In 2014 outcomes between the patients needing a change in their antibiotic compared to the patients where the empirical therapy was considered to be optimal were similar with respect to length of stay; 13.04 and 10.93 days (p = 0.34). In the 2012 group there was a significant increase in the length of stay in the group needing change in excess of 30 days (p = 0.02) compared to the group where empirical therapy was considered to be optimal, this clearly showed an improvement in the quality of care received after the rapid identification was instituted in 2014. The 2012 group had a four times overall increased sepsis associated mortality risk compared to the 2014 group and when empirical antibiotics needed to be optimized this risk was 7 times compared to the 2014 group. We conclude that rapid identification of bacterial pathogens in pediatric blood cultures with a rapid incubation MALDI-TOF identification protocol plays an important role in improving quality of care as part of a multidisciplinary approach to pediatric bacteremia and sepsis.

Meticillin-resistant Staphylococcus aureus (MRSA) bloodstream infection is responsible for significant morbidity, with mortality rates as high as 60% if not treated appropriately. We describe a rapid method to detect MRSA in blood cultures using a combined three-hour short incubation BRUKER matrix-assisted laser desorption/ionization time-of-flight MS BioTyper protocol and a qualitative immunochromatographic assay, the Alere Culture Colony Test PBP2a detection test. We compared this combined method with a molecular method detecting the nuc and mecA genes currently performed in our laboratory. One hundred and seventeen S. aureus blood cultures were tested of which 35 were MRSA and 82 were meticillin-sensitive S. aureus (MSSA). The rapid combined test correctly identified 100% (82/82) of the MSSA and 85.7% (30/35) of the MRSA after 3 h. There were five false negative results where the isolates were correctly identified as S. aureus, but PBP2a was not detected by the Culture Colony Test. The combined method has a sensitivity of 87.5%, specificity of 100%, a positive predictive value of 100% and a negative predictive value of 94.3% with the prevalence of MRSA in our S. aureus blood cultures. The combined rapid method offers a significant benefit to early detection of MRSA in positive blood cultures.

BACKGROUNDHip and knee arthroplasty infections are associated with considerable healthcare costs. The merits of reducing the postoperative surveillance period from 1 year to 90 days have been debated.OBJECTIVESTo report the first pan-Canadian hip and knee periprosthetic joint infection (PJI) rates and to describe the implications of a shorter (90-day) postoperative surveillance period.METHODSProspective surveillance for infection following hip and knee arthroplasty was conducted by hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP) using standard surveillance definitions.RESULTSOverall hip and knee PJI rates were 1.64 and 1.52 per 100 procedures, respectively. Deep incisional and organ-space hip and knee PJI rates were 0.96 and 0.71, respectively. In total, 93% of hip PJIs and 92% of knee PJIs were identified within 90 days, with a median time to detection of 21 days. However, 11%–16% of deep incisional and organ-space infections were not detected within 90 days. This rate was reduced to 3%–4% at 180 days post procedure. Anaerobic and polymicrobial infections had the shortest median time from procedure to detection (17 and 18 days, respectively) compared with infections due to other microorganisms, including Staphylococcus aureus.CONCLUSIONSPJI rates were similar to those reported elsewhere, although differences in national surveillance systems limit direct comparisons. Our results suggest that a postoperative surveillance period of 90 days will detect the majority of PJIs; however, up to 16% of deep incisional and organ-space infections may be missed. Extending the surveillance period to 180 days could allow for a better estimate of disease burden.Infect Control Hosp Epidemiol 2017;38:147–153

OBJECTIVE To assess clinically relevant outcomes after complete cessation of control measures for vancomycin-resistant enterococci (VRE). DESIGN Quasi-experimental ecological study over 3.5 years. METHODS All VRE screening and isolation practices at 4 large academic hospitals in Ontario, Canada, were stopped on July 1, 2012. In total, 618 anonymized abstracted charts of patients with VRE-positive clinical isolates identified between July 1, 2010, and December 31, 2013, were reviewed to determine whether the case was a true VRE infection, a VRE colonization or contaminant, or a true VRE bacteremia. All deaths within 30 days of the last VRE infection were also reviewed to determine whether the death was fully or partially attributable to VRE. All-cause mortality was evaluated over the study period. Generalized estimating equation methods were used to cluster outcome rates within hospitals, and negative binomial models were created for each outcome. RESULTS The incidence rate ratio (IRR) for VRE infections was 0.59 and the associated P value was .34. For VRE bacteremias, the IRR was 0.54 and P=.38; for all-cause mortality the IRR was 0.70 and P=.66; and for VRE attributable death, the IRR was 0.35 and P=.49. VRE control measures were not significantly associated with any of the outcomes. Rates of all outcomes appeared to increase during the 18-month period after cessation of VRE control measures, but none reached statistical significance. CONCLUSION Clinically significant VRE outcomes remain rare. Cessation of all control measures for VRE had no significant attributable adverse clinical impact. Infect Control Hosp Epidemiol 2016;1-7.

BACKGROUND: Increasing antimicrobial resistance has been identified as an important global health threat. Antimicrobial use is a major driver of resistance, especially in the hospital sector. Understanding the extent and type of antimicrobial use in Canadian hospitals will aid in developing national antimicrobial stewardship priorities. METHODS: In 2002 and 2009, as part of one-day prevalence surveys to quantify hospital-acquired infections in Canadian Nosocomial Infection Surveillance Program hospitals, data were collected on the use of systemic antimicrobial agents in all patients in participating hospitals. Specific agents in use (other than antiviral and antiparasitic agents) on the survey day and patient demographic information were collected. RESULTS: In 2002, 2460 of 6747 patients (36.5%) in 28 hospitals were receiving antimicrobial therapy. In 2009, 3989 of 9953 (40.1%) patients in 44 hospitals were receiving antimicrobial therapy (P<0.001). Significantly increased use was observed in central Canada (37.4% to 40.8%) and western Canada (36.9% to 41.1%) but not in eastern Canada (32.9% to 34.1%). In 2009, antimicrobial use was most common on solid organ transplant units (71.0% of patients), intensive care units (68.3%) and hematology/oncology units (65.9%). Compared with 2002, there was a significant decrease in use of first-and second-generation cephalosporins, and significant increases in use of carbapenems, antifungal agents and vancomycin in 2009. Piperacillin-tazobactam, as a proportion of all penicillins, increased from 20% in 2002 to 42.8% in 2009 (P<0.001). There was a significant increase in simultaneous use of >1 agent, from 12.0% of patients in 2002 to 37.7% in 2009. CONCLUSION: From 2002 to 2009, the prevalence of antimicrobial agent use in Canadian Nosocomial Infection Surveillance Program hospitals significantly increased; additionally, increased use of broad-spectrum agents and a marked increase in simultaneous use of multiple agents were observed.

BACKGROUND: Increasing antimicrobial resistance has been identified as an important global health threat. Antimicrobial use is a major driver of resistance, especially in the hospital sector. Understanding the extent and type of antimicrobial use in Canadian hospitals will aid in developing national antimicrobial stewardship priorities. METHODS: In 2002 and 2009, as part of one-day prevalence surveys to quantify hospital-acquired infections in Canadian Nosocomial Infection Surveillance Program hospitals, data were collected on the use of systemic antimicrobial agents in all patients in participating hospitals. Specific agents in use (other than antiviral and antiparasitic agents) on the survey day and patient demographic information were collected. RESULTS: In 2002, 2460 of 6747 patients (36.5%) in 28 hospitals were receiving antimicrobial therapy. In 2009, 3989 of 9953 (40.1%) patients in 44 hospitals were receiving antimicrobial therapy (P 1 agent, from 12.0% of patients in 2002 to 37.7% in 2009. CONCLUSION: From 2002 to 2009, the prevalence of antimicrobial agent use in Canadian Nosocomial Infection Surveillance Program hospitals significantly increased; additionally, increased use of broadspectrum agents and a marked increase in simultaneous use of multiple agents were observed.

Introduction: Cellulosimicrobium cellulans is a rare human pathogen that is associated with chronic immunosuppression, such as human immunodeficiency virus infection, post‐transplantation or end‐stage renal disease. Case presentation: A 59‐year old man with a past medical history of significant cardiovascular, cerebrovascular and peripheral vascular disease was admitted to the intensive care unit (ICU) with intractable seizures. Physical examination, radiographic imaging and culture results suggested the patient had developed metabolic encephalopathy due to pneumonia caused by Staphylococcus aureus and Moraxella catarrhalis. The patient recovered neurologically with the use of broad‐spectrum antibiotics but developed acute renal failure during his stay. Seven days later, he relapsed into seizure activity and two separate blood cultures grew Cellulosimicrobium cellulans. Despite maximal antibiotic therapy, the patient continued to deteriorate. After 16 days, the patient’s family withdrew care and he subsequently died. Conclusion: We report the isolation of Cellulosimicrobium cellulans from a patient who developed acute renal failure following a prolonged stay in the ICU for sepsis encephalopathy.

Background: In cases of bacteremia, a rapid bacterial identification to the genus and species level is critical to ensure the timely and correct treatment with an antimicrobial agent. The identification of the bacterial agent directly from positive blood culture broths could reduce the time to initiating the most appropiate antibiotic therapy. Methods & Materials: We evaluated the direct identification of micro-organisms from VersaTrek positive blood culture bottles using the Bruker Microflex matrix assisted laser desorption/ionization (MALDI) time of flight (TOF).One hundred and seven positive blood culture bottles were flagged positive by the VersaTrek blood culture system. Only positive blood cultures suggestive of a monomicrobial infection were included in the comparison. One hundred and two blood cultures had a single morphologically appearance on Gram stain suggesting a monomicrobial infection. Bacterial extraction was performed by using two different methods: the MALDI SepsiTyper kit (Bruker) and an in-house 7% saponin lysis method In total, 102 monobacterial cultures were included in this study. The methods was compared to the final culture result identified to genus and species level. Results: Among the 102 monomicrobial cultures, we identified 62 Gram positive organisms and 40 Gram negative cultures were identified using the two methods. A total of 93% Gram negative organisms and 84% of Gram positive bacteria with the saponin extraction method and 88% Gram negative and 81% Gram positive organisms using the SepsiTyper kit respectively were correctly identified to species level if compared to the final culture result. The analysis of the time-to-result demonstrated a reduction in the turnaround time foridentification ranging from one hour to twenty four hours, when performing the blood culture direct identification in comparison with the conventional method, whatever the extraction method. Conclusion: The conclusion we came to is that in our laboratory the saponin extraction method provides a reliable alternative to the SepsiTyper direct extraction method for Gram negative organisms and Gram positive organisms. Further evaluation of mixed cultures and an improved identification data library may improve identification in mixed cultures.

BACKGROUND:Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infections (BSI) are associated with considerable morbidity and mortality, especially with persistent (PB) or recurrent bacteremia (RB).OBJECTIVE:To determine the frequency of PB and RB in patients with MRSA BSI, and to characterize the isolates from these patients.METHODS:Surveillance for MRSA BSI was performed for one year in 13 Canadian hospitals. PB was defined as a positive blood culture that persisted for ≥7 days; RB was defined as the recurrence of a positive blood culture ≥14 days following a negative culture. Isolates were typed using pulsed-field gel electrophoresis (PFGE). Vancomycin susceptibility was determined using Etest.RESULTS:A total of 183 patients with MRSA BSI were identified; 14 (7.7%) had PB and five (2.7%) had RB. Ten (5.5%) patients were known to have infective endocarditis, and five of these patients had PB or RB. Initial and subsequent MRSA isolates from patients with PB and RB had the same PFGE type. There were no significant differences in the distribution of PFGE types in patients with PB or RB (37% CMRSA-2/USA100; 37% CMRSA-10/USA300) compared with that in other patients (56% CMRSA-2/USA100; 32% CMRSA-10/USA300). All isolates were susceptible to vancomycin, but patients with PB or RB were more likely to have initial isolates with vancomycin minimum inhibitory concentration = 2.0 μg/mL (26% versus 10%; P=0.06).CONCLUSIONS:Persistent or recurrent MRSA bacteremia occurred in 10.4% of patients with MRSA BSIs. Initial isolates from patients with persistent or recurrent MRSA BSIs were more likely to exhibit reduced susceptibility to vancomcyin, but were not associated with any genotype.

BACKGROUND:The literature suggests that positive results of catheter urine cultures frequently lead to unnecessary antimicrobial prescribing, which therefore represents an important target for stewardship.OBJECTIVE:To assess the appropriateness of antibiotic prescribing in response to the results of urine cultures from patients with indwelling urinary catheters.METHODS:This retrospective study was conducted at a tertiary care centre and involved adults with indwelling urinary catheters from whom urine specimens were obtained for culture. Patients with positive or negative culture results were identified from microbiology laboratory reports. The medical records of consecutive patients were screened to select a sample of 80 inpatients (40 per group). Abstracted patient histories were independently evaluated by an expert panel of 3 infectious diseases consultants blinded to the decisions of prescribers and of fellow panelists. The primary end point was concordance of each patient's treatment decision (with respect to the indication) between the expert panel (based on majority agreement, i.e., at least 2 of the 3 expert panelists) and the prescriber. The secondary end points were unnecessary days of therapy and selected outcomes over a predefined period after urine was obtained for culture.RESULTS:A total of 591 charts were screened to generate the targeted number of patients. Baseline demographic characteristics were comparable for the 2 groups, except antibiotic exposure before urine collection was significantly more frequent for the group with negative culture results. The treatment decision was concordant in 40% (16/40) of the patients with a positive culture result and 85% (34/40) of those with a negative culture result (p < 0.001). The most common reason for discordance was administration of antibiotics when not indicated (23 of 24 patients with a positive result and 5 of 6 patients with a negative result), which accounted for 165 and 32 unnecessary days of therapy per 1000 inpatient-days, respectively (p < 0.001). Adverse effects occurred in 2 of the 23 patients with a positive result who received antibiotics that were not indicated.CONCLUSIONS:Appropriateness of antibiotic prescribing, as measured by concordance of decisions between the expert panel and prescribers, was more common among patients with negative urine culture results than among those with positive results. However, there is an opportunity to improve prescribing for both groups through antimicrobial stewardship initiatives. Unnecessary days of therapy and adverse effects were more common in patients with a positive culture result.

The genomes of 47 coagulase-negative staphylococcal strains assigned to different species were analysed by pulsed-field electrophoresis. The strains were clustered on the basis of their similarity in the SmaI restriction patterns into various groups, each group consisting of the type strain and the strains whose SmaI restriction patterns were similar to that of the type strain. The SmaI restriction groups seem to correspond to the following species: Staphylococcus warneri, S. hominis, S. xylosus, S. lugdunensi, S. kloosii, S. haemolyticus, S. lentus, S. cohnii, S. equorum, S. chromogenes, S. saprophyticus, S. simulans, S. carnosus, S. capitis and S. auricularis. The species S. sciuri, S. caseolyticus, S. gallinarum, S. epidermidis and S. schleiferi were represented only by their type strains and showed no similarity in their SmaI restriction patterns neither to each other nor to all the species investigated here. Thus, the classification of coagulase-negative staphylococcal strains into the above species seems to be confirmed also by genome restriction analysis carried out by pulsed-field gel electrophoresis.

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.

Coagulase-negative staphylococci (CoNS) have emerged as important nosocomial pathogens. CoNS resistance to meticillin and other semisynthetic penicillins is now common. Elevated vancomycin minimal inhibitory concentrations (MICs) have been reported and are associated with worse treatment outcomes. Several newer antibiotics have recently become available for the treatment of Gram-positive infections. The purpose of this study was to assess the in vitro activity of telavancin, daptomycin, linezolid and tigecycline in comparison with oxacillin and vancomycin against 653 non-duplicate clinical isolates of CoNS by the agar dilution method. The greatest variability in MIC was observed for oxacillin. Presence of the mecA gene conferred higher MICs for oxacillin but did not influence MICs to all other antibiotics tested. Telavancin tended to have MICs that were 1-2 dilutions lower than vancomycin. Daptomycin had good activity against all isolates. Staphylococcus haemolyticus, Staphylococcus hominis subsp. novobiosepticus, Staphylococcus saprophyticus, Staphylococcus schleiferi and Staphylococcus simulans were the most daptomycin-susceptible CoNS species tested. The validity of the agar dilution method for daptomycin was confirmed, with >90% isolates having MICs that were within 1 dilution of parallel Etest results. Within-species MIC variation was most restricted for linezolid and tigecycline, with the exception of Staphylococcus epidermidis and Staphylococcus haemolyticus that demonstrated higher overall MICs to tigecycline.

BACKGROUND:Health care-associated infections (HAIs) cause considerable morbidity and mortality to hospitalized patients. The objective of this point prevalence study was to assess the burden of HAIs in the Canadian pediatric population, updating results reported from a similar study conducted in 2002. METHODS:A point prevalence survey of pediatric inpatients was conducted in February 2009 in 30 pediatric or combined adult/pediatric hospitals. Data pertaining to one 24-hour period were collected, including information on HAIs, microorganisms isolated, antimicrobials prescribed, and use of additional (transmission based) precautions. The following prevalent infections were included: pneumonia, urinary tract infection, bloodstream infection, surgical site infection, viral respiratory infection, Clostridium difficile infection, viral gastroenteritis, and necrotizing enterocolitis. RESULTS:One hundred eighteen patients had 1 or more HAI, corresponding to a prevalence of 8.7% (n = 118 of 1353, 95% confidence interval: 7.2-10.2). Six patients had 2 infections. Bloodstream infections were the most frequent infection in neonates (3.0%), infants (3.1%), and children (3.5%). Among all patients surveyed, 16.3% were on additional precautions, and 40.1% were on antimicrobial agents, whereas 40.7% of patients with a HAI were on additional precautions, and 89.0% were on antimicrobial agents. CONCLUSION:Overall prevalence of HAI in 2009 has remained similar to the prevalence reported from 2002. The unchanged prevalence of these infections nonetheless warrants continued vigilance on their prevention and control.

Objectives This study aimed to estimate the city-wide prevalence of methicillin-resistant Staphylococcus aureus (MRSA) in patients (≥18 years old) presenting with skin and soft tissue infections (SSTIs) to the emergency departments (EDs) of a Canadian Academic Health Care Center. Secondary objectives were to identify demographic and clinical variables associated with MRSA, and determine MRSA antimicrobial susceptibilities and genotypes. Methods This prospective observational study was conducted over 2 months. Participants completed a Health and Lifestyle Questionnaire. Cultures of the infection site, nares, and throat were obtained and MRSA isolates were confirmed by polymerase chain reaction. Patient characteristics were summarized using descriptive statistics and MRSA prevalence and 95% confidence intervals were estimated using standard equations. Backwards stepwise multivariate logistic regression models determined predictor variables independently associated with MRSA colonization or infection. Results Of 205 patients, 35 (17.1%) were infected or colonized with MRSA. Seventy-eight (38.0%) of the infection site cultures grew S. aureus of which 27 (34.6%) were MRSA. Incarceration, known exposure to MRSA and involvement in competitive sports were significant predictors of MRSA SSTIs. Antimicrobial susceptibility among MRSA isolates was trimethoprim/sulfamethoxazole, vancomycin, gentamicin, and linezolid 100%, clindamycin 75%, ciprofloxacin 59.3%, and erythromycin 7.4%. Sixty-nine percent of MRSA cases fit the clinical definition of community associated; subsequently 77% were confirmed as CMRSA 10, a recognized community-acquired MRSA. Conclusion Community-acquired -MRSA is a significant pathogen of SSTIs in EDs of a Canadian teaching center. MRSA should be considered when initiating empiric antibiotic therapy, particularly in patients with risk factors.

Objectives: To evaluate the usefulness of the cefoxitin screen in Vitek(R) 2 Gram-positive panels for recognizing methicillin-resistant strains of staphylococci.Methods: Seven hundred and ninety-nine non-duplicate isolates of Staphylococcus aureus and coagulase-negative strains were included in the study. Methicillin resistance was measured using PCR for the mecA gene, the CLSI cefoxitin disc diffusion method, the Vitek(R) 2 cefoxitin screen and the Vitek(R) 2 oxacillin susceptibility test.Results: Compared with the molecular detection of methicillin resistance the overall sensitivities and specificities of the phenotypic tests for cefoxitin disc diffusion were 94.9% and 97.0%, for Vitek(R) 2 cefoxitin screen were 94.6% and 93.5% and for Vitek(R) 2 oxacillin susceptibility test were 93.8% and 77.9%. The cephamycin tests (cefoxitin disc diffusion and Vitek(R) 2 screen) were not able to identify mecA-positive strains of Staphylococcus simulans. In addition, the performance of the Vitek(R) 2 system was poor against Staphylococcus cohnii subspecies, Staphylococcus hominis hominis and Staphylococcus saprophyticus.Conclusions: Overall, the performance of the Vitek(R) 2 system for differentiating mecA-positive staphylococci was comparable to PCR and the CLSI disc diffusion method; however, performance was species-dependent. Thus, before accepting the results produced by Vitek(R) 2, species identification may be required.