Accuracy of hospital-based surveillance systems for surgical site infection after adult spine surgery: a Bayesian latent class analysis.

BACKGROUND: Surgical site infections (SSIs) of the spine are morbid and costly complications. An accurate surveillance system is required to properly describe the disease burden and the impact of interventions that mitigate SSI risk. Unfortunately, uniform approaches to conducting SSI surveillance are lacking because of varying SSI case definitions, the lack of a perfect reference case definition and heterogeneous data sources. AIM: To assess the accuracy of four independent data sources that capture SSIs after spine surgery, with estimation of a measurement-error-adjusted SSI incidence. METHODS: A Bayesian latent class model assessed the sensitivity/specificity of each data source to identify SSI and to estimate a measurement-error-adjusted incidence. The four data sources used were: the discharge abstract database (DAD), the National Surgical Quality Improvement Program (NSQIP) database, the Infection Prevention and Control Canada (IPAC) database, and the Spine Adverse Events Severity database. FINDINGS: A total of 904 patients underwent spine surgery in 2017. The most sensitive data source was DAD (0.799; 95% credible interval (CrI): 0.597-0.943); the least sensitive was NSQIP (0.497; 95% CrI: 0.308-0.694). The most specific data source was IPAC (0.997; 95% CrI: 0.993-1.000) and the least specific was DAD (0.969; 95% CrI: 0.956-0.981). The measurement-error-adjusted SSI incidence was 0.030 (95% CrI: 0.019-0.045). The crude incidence using the DAD overestimated the incidence, and the three other data sources underestimated it. CONCLUSION: SSI surveillance in the spine surgery population is feasible using several data sources, provided that measurement error is considered.

Reduction in community-onset methicillin-resistant Staphylococcus aureus rates in an urban Canadian hospital setting.

Community-onset methicillin resistant Staphylococcus aureus (CO-MRSA) became a prominent cause of infection in North America in 2003, with a peak in the epidemic noted by multiple groups in the USA between 2005 and 2007. We reviewed rates of MRSA in two hospitals in Vancouver, Canada, to observe changes in epidemiology from 2003 to 2011. Episodes of emergency department (ED) MRSA bacteraemia and wounds were extracted from the laboratory database, with rates calculated per 10,000 ED visits. All cases were assumed to be community onset, as they were diagnosed in the ED. A peak in ED MRSA bacteraemias occurred in 2005, at 7·8/10,000 ED visits. By 2011, rates of ED bacteraemia declined significantly to 3·3/10,000 ED visits (P

Economic analysis of vancomycin-resistant enterococci at a Canadian hospital: assessing attributable cost and length of stay.

BACKGROUND: Competing resource demands have resulted in the de-escalation of vancomycin-resistant enterococcus (VRE) control programmes in some Canadian healthcare centres. AIM: To determine the attributable costs and length of stay (LOS) of VRE colonizations/infections in an acute care hospital in Canada. METHODS: Surveillance and financial hospital-based databases were used to conduct analyses with cases and controls from fiscal year 2008-2009 (1 April 2008 to 31 March 2009) at an acute care hospital in downtown Vancouver, Canada. A statistical analysis of attributable costs and LOS was conducted using a generalized linear model. In a secondary analysis, differences in costs and LOS were examined for VRE infections versus colonizations. FINDINGS: A total of 217 patients with VRE and a random sample of 1075 patients without VRE were examined. VRE has a positive and significant impact on patient hospitalization costs and LOS. Overall, the presence of VRE increased the estimated mean cost per patient by 61.9% (95% confidence interval: 42.3-84.3) in relative terms and $17,949 (13,949-21,464) in absolute Canadian dollars. For LOS, the attributable number of days associated with a VRE case mean was 68.0% (41.9-98.9) higher in relative terms and 13.8 days (10.0-16.9) in absolute days. In the secondary analysis comparing VRE infection and colonization costs, no statistically significant difference was found. CONCLUSIONS: Based on this analysis, the attributable cost and LOS of VRE are considerable. These factors should be considered before de-escalation of a hospital VRE control programme.

Classification of MRSA cases detected at the time of hospital admission: does the 'look-back' period matter?

Limited resources for infection control necessitate efficient local surveillance. Cases of meticillin-resistant Staphylococcus aureus from the authors' hospital surveillance system were examined to determine if attribution of cases as healthcare-associated or non-healthcare-associated differed when using a 12-month vs a four-week 'look-back' period. Two additional cases were reclassified from non-healthcare-associated to healthcare-associated, representing a 2% reclassification rate between four-week and 12-month criteria (P = 0.857). Infection control programmes may save time and resources by minimizing retrospective review of records without compromising data quality due to misclassification.

Polymerase chain reaction assay to detect Clostridium difficile tcdC variants is valuable in characterizing hospital epidemiology.

The epidemiology of nosocomial Clostridium difficile infection (CDI), acquired at two hospitals in Vancouver over a one-year period, was reviewed. Cases were analysed by tcdC polymerase chain reaction, with tcdC variants (18 base pair deletion) highly associated with the NAP1 strain. Of the 214 cases identified, 51.9% were caused by these tcdC variants; these cases occurred more frequently in older patients admitted to the community hospital where the strain was endemic. Overall, at least five out of 24 cases classified as recurrences by surveillance definitions were reinfections. Molecular testing allowed identification of major epidemiological differences between the hospitals studied and provided more accurate classification of CDI cases.

Screening for methicillin-resistant Staphylococcus aureus (MRSA) in community-recruited injection drug users: are throat swabs necessary?

We examined and described colonization of MRSA in the anterior nares and throat from 184 community-recruited injection drug users. Thirty-seven (20%) were positive for MRSA: most (34, 92%) were carriers in the nares; while only three (8%) were carriers detected by throat swabs alone. The majority (29, 78%) of MRSA isolates were PVL positive.

Community-associated methicillin-resistant Staphylococcus aureus is prevalent in wounds of community-based injection drug users.

Injection drug users (IDUs) have an elevated risk for carriage of Staphylococcus aureus, including methicillin-resistant S. aureus (MRSA). Cutaneous injection-related infections are common in IDUs but detailed studies are few. Based on a subsample of 218 individuals from a community-recruited cohort of IDUs at a supervised injection facility, we investigated the microbiology and related antibiotic susceptibility profiles of isolates from 59 wounds. Twenty-seven percent of subjects had at least one wound and 25 (43%) were culture positive for S. aureus alone [14 MRSA and 11 (19%) methicillin-susceptible (MSSA) isolates]. Sixteen of 18 MRSA isolates were classified as community associated (CA) by the presence of genes encoding for PVL. MRSA and MSSA occurred in mixed infection with other organisms on three and six occasions, respectively. All CA-MRSA isolates were susceptible to tetracycline, vancomycin and linezolid but only 13% were susceptible to clindamycin compared to 63% of MSSA isolates. The frequency of CA-MRSA is a cause for concern in wound infection in the IDU setting.