Device and surgical procedure-related infections in Canadian acute care hospitals from 2011 to 2020

The median age of patients with a paediatric cardiac SSI was 19 days (IQR=7–193 days), and the median time from surgery to onset date of infection was 10 days (IQR=5–19 days). Among the four deaths reported within 30 days of infection onset (1.7% of cases), two deaths were unrelated to the paediatric cardiac SSI, while two were attributable to the paediatric cardiac SSI. Staphylococcus aureus and CoNS were the most commonly identified pathogens from paediatric cardiac SSIs (48% and 22% of identified pathogens, respectively) and did not differ by superficial, organ/space or deep infection type (data not shown).

Antibiogram

Results of antimicrobial susceptibility testing for the most frequently identified gram-positive, gram-negative and fungal pathogens from device and surgical procedure-related HAIs are listed in Table 5 and Table 6. The S. aureus isolates were resistant to cloxacillin/oxacillin (methicillin-resistant S. aureus [MRSA]) in 15% (n=32/218) of CLABSIs and 14% (n=40/284) of other reported SSIs. Meropenem resistance ranged from 2%–7% in gram-negative pathogens identified from CLABSIs. No meropenem resistance was observed among pathogens isolated from SSIs. Fifty-one vancomycin-resistant Enterococci were identified among CLABSIs (16%).

Discussion

This report summarizes 4,751 device and surgical procedure-related HAIs identified over 10 years of surveillance from 2011 to 2020. Rates of device and surgical procedure-related HAIs have doubled for adult mixed ICU CLABSIs while NICU CLABSI and knee SSI rates have significantly decreased 60% and 58%, respectively. The most frequently reported pathogens in this report were generally aligned with those reported in a 2020 United States (US) National Healthcare Surveillance Network (NHSN) report of adult HAIs, indicating S. aureus, E. coli and Klebsiella among the most frequently reported pathogens for device and surgical procedure-related HAIs in both Canada and the US, while CoNS was identified more commonly in Canada^{Footnote 9}. The COVID-19 pandemic may have had differing impacts on the rates of device and surgical procedure-related HAIs in Canada and the US^{Footnote 10}. Investigation is underway to assess the influence of pandemic-related factors such as changes in infection control practices, hospital resource capacity, screening, laboratory testing and antimicrobial stewardship on the observed rates of HAIs.

Central line-associated bloodstream infections

The overall rates of CLABSI in adult ICUs (0.6 and 1.1 per 1,000 line days for CVICUs and mixed ICUs, respectively) were similar to those reported in the US and Australia. The 2013 CLABSI rate in US medical/surgical ICUs was estimated to be 0.8 per 1,000 line days^{Footnote 11}. In Australia, annual rates of CLABSIs in adult ICUs ranged between 0.9 and 1.4 CLABSIs per 1,000 line days from 2011–2013^{Footnote 12}. While CLABSI rates in adult mixed ICUs, CVICUs and PICUs have increased or remained stable in Canada since 2011, rates in NICUs have decreased by 60%. Data available from the US since 2016 indicate similar trends for CLABSIs in neonatal critical care locations, where the standardized incidence ratios (defined as the ratio of observed number of infections compared to the 2015 baseline) decreased by 27%^{Footnote 13Footnote 14Footnote 15Footnote 16Footnote 17}. These decreased CLABSI rates in the US may be attributed to the updated NHSN guidelines for the prevention of CLABSI, implemented in 2011^{Footnote 18Footnote 19}.

Higher rates of CLABSIs are seen in other regions; a large surveillance study of intensive care units in 45 countries from Latin America, Europe, Eastern Mediterranean, Southeast Asia and Western Pacific World Health Organization regions reported pooled mean CLABSI rates of 7.2 per 1,000 line days in PICUs, 5.1 in medical/surgical adult ICUs and 12.0 in NICUs (between January 2012 and December 2017)^{Footnote 11}.

Surgical site infections

Among SSIs included in this surveillance report, hip and knee SSIs were the most common. Hip SSI rates remained stable across the reported years, while a decreasing trend in knee SSI rates was observed. Surveillance from the European Centre for Disease Prevention and Control reported similar trends, indicating stable hip SSI rates and decreasing knee SSI rates for study years 2014 to 2017^{Footnote 20}. In a US point prevalence study, a reduction in the prevalence of complex SSIs was observed between 2011 and 2015^{Footnote 21}. In accordance with pathogen results from other regions, the most common pathogens among hip and knee-SSIs were S. aureus and CoNS^{Footnote 20Footnote 22}. Frequent identification of these two pathogens may be attributable to the use of implant devices and contamination from the patient’s endogenous skin flora^{Footnote 9}. Joint replacements typically occur in older adults, which explains the high median age for hip and knee SSI^{Footnote 23}. Joint replacements among older populations are also prone to surgical complications, such as prosthetic joint infections^{Footnote 23}. Data indicate that surgical site infections frequently lead to readmission and revision surgery, both of which result in high financial and resource burdens on the healthcare system^{Footnote 24}.

The overall rate of surgical site infections from CSF shunts was 2.9 per 100 surgeries. This aligns with rates reported from a 2012 multi-country review, which range from 3% to 12%^{Footnote 25}. Stratification of CSF shunt SSI data by paediatric and adult/mixed hospitals showed that adult rates (2.8/100 surgeries) and paediatric rates (3.0/100 surgeries) were similar from 2011–2020. Data from a previous CNISP study conducted between 2000 and 2002 indicated a higher paediatric rate than the adult rate of CSF shunt SSI^{Footnote 26}. Given that the rate of CSF shunt SSI among paediatric patients from 2011–2020 (3.0%) is lower than that from 2000–2002 (4.9%), there is evidence of a decrease in SSI rates among paediatric populations^{Footnote 26}. Meanwhile, the rate of CSF shunt SSI among adult patients from 2011–2020 (2.8%) remains relatively unchanged compared to that of 2000–2002 (3.2%)^{Footnote 26}.

The overall rate of paediatric cardiac SSI between 2011 and 2020 was 4.1 per 100 surgeries. The 2018 paediatric cardiac SSI rate should be interpreted with caution; given that the number of cases used to calculate this rate was limited, the rates may be sensitive to fluctuation attributed to individual hospital sites. Nevertheless, the overall rate was found to be comparable with infection rates reported elsewhere, despite limited literature about paediatric cardiac SSIs. A 2009–2012 intervention study of neonates undergoing cardiac surgery at a New York tertiary-care centre found pre and post-intervention paediatric cardiac SSI rates of 6.2 and 5.8/100 surgeries, respectively^{Footnote 27}. In France, 19% of patients younger than one year of age and undergoing cardiac surgery presented with a SSI during the study period, between 2012 and 2013^{Footnote 28}. The hospital-acquired cardiac-SSI rate at two New York hospitals was 1.4 infections per 100 procedures within 90 days for patients younger than 18 years of age, based on a retrospective study from 2010–2012^{Footnote 29}.

Antibiogram

The percentage of S. aureus isolates that were MRSA in this study (14%–15%) (Table 5 and Table 6) was slightly higher to what was reported from a Swiss surveillance network where 8% of S. aureus SSI cases were MRSA in 2010–2015^{Footnote 30}. Higher rates of MRSA have been reported elsewhere, such as in several centres in Latin America where resistance averaged 44.7% in 2017^{Footnote 31}. In the US, 42%–48% of S. aureus isolates from HAIs (including SSI, CLABSI and others) in NHSN surveillance were MRSA^{Footnote 9}.

Of the identified Enterococcus spp. in CLABSIs, 16% were vancomycin-resistant Enterococci, which is less than 30.9% identified as resistant in ICUs in Poland^{Footnote 32}. From NHSN surveillance in the US, 84.5% of Enterococcus faecium and 8.5% of Enterococcus faecalis pathogens identified from CLABSIs in ICUs were vancomycin-resistant Enterococci in 2015–2017^{Footnote 9}.

Meropenem resistance was low among the gram-negative pathogens identified among CLABSIs and SSIs (0%–7%). Similarly in the US, the percent of carbapenem resistance among Klebsiella spp. ranged from 3.1% (among SSIs) to 6.9% (among expanded list of device-associated infections); the percent of carbapenem resistance among E. coli ranged from 0.6% (among SSIs) to 0.7% (expanded list)^{Footnote 9}.

Strengths and limitations

The main strength of this study is the standardized collection of detailed data from a large network of sentinel hospitals for over ten years. The CNISP network extends across Canada, although it may not be representative of all Canadian acute care hospitals since the number of hospitals participating in each HAI surveillance project differed. However, recruitment is ongoing and CNISP coverage of Canadian acute care beds increased from 25% in 2011 to 30% in 2020. The CNISP is continuing to increase representativeness, especially among northern, community, rural and Indigenous populations.

The epidemiologic data collected were limited to the information available in the patient charts. For CLABSI surveillance, data were limited to infections occurring in the ICU settings, and as such may only represent a portion of CLABSIs occurring in the hospital. Further, differences in surveillance protocols and case definitions, as well as the lack of recent comparable data, limit comparison with data from other countries. The CNISP continues to support the national public health response to the COVID-19 pandemic. Future studies are ongoing to assess the impact of the COVID-19 pandemic on device and surgical procedure-related HAIs and AMR.

Conclusion

This report provides an updated summary of rates, pathogen distributions and antimicrobial resistance among select device and surgical procedure-related HAIs and relevant pathogens. The collection and analysis of national surveillance data are key to understanding and reducing the national burden of device and surgical procedure-related HAIs by providing benchmark rates for comparison nationally and internationally and informing antimicrobial stewardship and infection prevention and control programs and policies.

Authors’ statement

Canadian Nosocomial Infection Surveillance Program hospitals provided expertise in the development of protocols in addition to the collection and submission of epidemiological and microbiological data. Epidemiologists from Public Health Agency of Canada were responsible for the conception, analysis, interpretation, drafting and revision of the article.

Competing interests

None.

Acknowledgements

We gratefully acknowledge the contribution of the physicians, epidemiologists, infection control practitioners and laboratory staff at each participating hospital: Alberta Children’s Hospital, Calgary, Alberta (AB); BC Children’s Hospital, Vancouver, British Columbia (BC); BC Women’s Hospital, Vancouver, BC; CHU Sainte-Justine, Montréal, Québec (QC); Central Newfoundland Regional Health Centre, Grand Falls-Windsor, Newfoundland and Labrador (NL); Centre hospitalier de l’Université de Montréal (CHUM), Montréal, QC; Children’s Hospital of Eastern Ontario (CHEO), Ottawa, Ontario (ON); Children’s Hospital of Western Ontario, London, ON; Dartmouth General Hospital, Halifax, Nova Scotia (NS); Foothills Medical Centre, Calgary, AB; General Hospital & Miller Centre, St. John’s, NL; HHS General Site, Hamilton, ON; Halifax Infirmary, Halifax, NS; Health Sciences Centre-Winnipeg, Winnipeg, Manitoba (MB); Hôpital Maisonneuve-Rosemont, Montréal, QC; Hôtel-Dieu de Québec, Québec, QC; IWK Health Centre, Halifax, NS; James Paton Memorial Hospital, Gander, NL; Janeway Children’s Hospital and Rehabilitation Centre, St. John’s, NL; Jurvinski Hospital and Cancer Center, Hamilton, ON; Kelowna General Hospital, Kelowna, BC; Kingston General Hospital, Kingston, ON; Lachine General Hospital, Lachine, QC; Lion’s Gate Hospital, North Vancouver, BC; McMaster Children’s Hospital, Hamilton, ON; Montréal Children’s Hospital, Montréal, QC; Montréal General Hospital, Montréal, QC; Montréal Neurological Institute, Montréal, QC; Mount Sinai Hospital, Toronto, ON; Nanaimo Regional General Hospital, Nanaimo, BC; North York General Hospital, Toronto, ON; Pasqua Hospital, Regina, Saskatchewan (SK); Peter Lougheed Centre, Calgary, AB; Powell River General Hospital, Powell River, BC; Prince County Hospital, Summerside, Prince Edward Island (PE); Princess Margaret Hospital, Toronto, ON; Qikiqtani General Hospital, Iqaluit, Nunavut (NU); Queen Elizabeth Hospital, Charlottetown, PE; Regina General Hospital, Regina, SK; Rehabilitation Centre, Halifax, NS; Richmond General Hospital, Richmond, BC; Rockyview General Hospital, Calgary, AB; Royal Jubilee Hospital, Victoria, BC; Royal University Hospital, Saskatoon, SK; Royal Victoria Hospital, Montréal, QC; SMBD - Jewish General Hospital, Montréal, QC; Sechelt Hospital (formerly St. Mary’s), Sechelt, BC; Sir Thomas Roddick Hospital, Stephenville, NL; South Health Campus, Calgary, AB; Squamish General Hospital, Squamish, BC; St Joseph’s Healthcare, Hamilton, ON; St. Clare’s Mercy Hospital, St. John’s, NL; St. Paul’s Hospital, Saskatoon, SK; Stollery Children’s Hospital, Edmonton, AB; Sudbury Regional Hospital, Sudbury, ON; Sunnybrook Hospital, Toronto, ON; The Hospital for Sick Children, Toronto, ON; The Moncton Hospital, Moncton, New Brunswick (NB); The Ottawa Hospital Civic Campus, Ottawa, ON; The Ottawa Hospital General Campus, Ottawa, ON; Toronto General Hospital, Toronto, ON; Toronto Western Hospital, Toronto, ON; UBC Hospital, Vancouver, BC; University Hospital, London, ON; University of Alberta Hospital, Edmonton, AB; University of Manitoba Children’s Hospital, Winnipeg, MB; University of Ottawa Heart Institute, Ottawa, ON; Vancouver General Hospital (VGH), Vancouver, BC; Veterans Memorial Building, Halifax, NS; Victoria General Hospital, Victoria, BC; Victoria General, Halifax, NS; Victoria Hospital, London, ON; Western Memorial Regional Hospital, Corner Brook, NL.

Thank you to the staff at Public Health Agency of Canada in the Centre for Communicable Diseases and Infection Control, Ottawa, ON (J Brooks, L Pelude, R Mitchell, W Rudnick, KB Choi, A Silva, V Steele, J Cayen, C McClellan, D Lee, W Zhang, and J Bartoszko).

Funding

This work was supported by Public Health Agency of Canada.

Appendix: Case definitions

Central line-associated bloodstream infection

Only central line-associated bloodstream infections (BSIs) related to an intensive care unit (ICU) admission were included in surveillance.

Bloodstream infections case definition:

Bloodstream infection is NOT related to an infection at another site and it meets one of the following criteria:

Criterion 1: Recognized pathogen cultured from at least one blood culture, unrelated to infection at another site.

OR

Criterion 2: At least one of: fever (higher than 38°C core), chills, hypotension; if aged younger than 1 year, fever (higher than 38°C core), hypothermia (lower than 36°C core), apnea or bradycardia AND common skin contaminant (see list below) cultured from at least two blood cultures drawn on separate occasions or at different sites, unrelated to infection at another site. Different sites may include peripheral veins, central venous catheters or separate lumens of a multilumen catheter. Different times include two blood cultures collected on the same or consecutive calendar days via separate venipunctures or catheter entries. The collection date of the first positive blood culture is the date used to identify the date of positive culture. Two positive blood culture bottles filled at the same venipuncture or catheter entry constitute only one positive blood culture.

Central line-associated bloodstream infection case definition:

A central line-associated bloodstream infections (CLABSI) must meet one of the following criteria:

Criterion 1: A laboratory-confirmed bloodstream infection (LCBSI) where a central line catheter (CL) or umbilical catheter (UC) was in place for more than two calendar days on the date of the positive blood culture, with day of device placement being Day 1.

OR

Criterion 2: A LCBSI where a CL or UC was in place more than two calendar days and then removed on the day or one day before positive blood culture was drawn.

Intensive care unit-related central line-associated bloodstream infection case definition:

A CLABSI related to an ICU if it meets one of the following criteria:

Criterion 1: CLABSI onset after two days of ICU stay.

OR

Criterion 2: If the patient is discharged or transferred out of the ICU, the CLABSI would be attributable to the ICU if it occurred on the day of transfer or the next calendar day after transfer out of the ICU.

Note: If the patient is transferred into the ICU with the CL and the blood culture was positive on the day of transfer or the next calendar day, then the CLABSI would be attributed to the unit where the line was inserted.

Common skin contaminants:

Diphtheroids, Corynebacterium spp., Bacillus spp., Propionibacterium spp., coagulase-negative staphylococci (including S. epidermidis), viridans group streptococci, Aerococcus spp., Micrococcus spp. and Rhodococcus spp.

Hip and knee surgical site infection

Only complex surgical site infections (SSIs) (deep incisional or organ/space) following hip and knee arthroplasty were included in surveillance.

A deep incisional surgical site infection must meet the following criterion:

Infection occurs within 90 days after the operative procedure and the infection appears to be related to the operative procedure and involves deep soft tissues (e.g. facial and muscle layers) of the incision and the patient has at least ONE of the following:

• Purulent drainage from the deep incision but not from the organ/space component of the surgical site
• Deep incision that spontaneously dehisces or is deliberately opened by the surgeon and is culture-positive or not cultured when the patient has at least one of the following signs or symptoms: fever (higher than 38°C) or localized pain or tenderness (a culture-negative finding does not meet this criterion)
• An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation or by histopathologic or radiologic examination
• Diagnosis of a deep incisional SSI by a surgeon or attending physician

An organ/space surgical site infection must meet the following criterion:

Infection occurs within 90 days after the operative procedure and the infection appears to be related to the operative procedure and infection involves any part of the body, excluding the skin incision, fascia or muscle layers, that is opened or manipulated during the operative procedure and patient has at least ONE of the following:

• Purulent drainage from a drain that is placed through a stab wound into the organ/space
• Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/space
• An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation or by histopathologic or radiologic examination
• Diagnosis of an organ/space SSI by a surgeon or attending physician

Cerebrospinal fluid shunt surgical site infection

Only patients who underwent a placement or revision of a cerebrospinal fluid (CSF) shunting device and the infection occurred within one year of surgery were included in surveillance.

Cerebrospinal fluid shunt-associated surgical site infection case definition:

An internalized CSF shunting device is in place AND a bacterial or fungal pathogen(s) is identified from the cerebrospinal fluid AND is associated with at least ONE of the following:

• Fever (temperature 38°C or higher)
• Neurological signs or symptoms
• Abdominal signs or symptoms
• Signs or symptoms of shunt malfunction or obstruction

Paediatric cardiac surgery surgical site infection

Only surgical site infections following open-heart surgery with cardiopulmonary bypass among paediatric patients (younger than 18 years of age) were included in surveillance.

A superficial incisional SSI must meet the following criterion: Infection occurs within 30 days after the operative procedure and involves only skin and subcutaneous tissue of the incision and meets at least ONE of the following criteria:

• Purulent drainage from the superficial incision
• Organisms isolated from an aseptically obtained culture of fluid or tissue from the superficial incision
• At least ONE of the following signs or symptoms of infection:
  • Pain or tenderness, localized swelling, redness or heat, and the superficial incision is deliberately opened by a surgeon, and is culture-positive or not cultured (a culture-negative finding does not meet this criterion)
  • Diagnosis of superficial incisional SSI by the surgeon or attending physician

A deep incisional SSI must meet the following criterion:

Infection occurs within 90 days after the operative procedure and the infection appears to be related to the operative procedure AND involves deep soft tissues (e.g. facial and muscle layers) of the incision AND the patient has at least ONE of the following:

• Purulent drainage from the deep incision but not from the organ/space component of the surgical site
• Deep incision spontaneously dehisces or is deliberately opened by the surgeon and is culture-positive or not cultured when the patient has at least one of the following signs or symptoms: fever (higher than 38°C) or localized pain or tenderness (a culture-negative finding does not meet this criterion)
• An abscess or other evidence of infection involving the deep incision is found on direct examination, during reoperation or by histopathologic or radiologic examination
• Diagnosis of a deep incisional SSI by a surgeon or attending physician

An organ/space SSI must meet the following criterion:

Infection occurs within 90 days after the operative procedure and the infection appears to be related to the operative procedure AND infection involves any part of the body, excluding the skin incision, fascia or muscle layers, that is opened or manipulated during the operative procedure AND the patient has at least ONE of the following:

• Purulent drainage from a drain that is placed through a stab wound into the organ/space
• Organisms isolated from an aseptically obtained culture of fluid or tissue in the organ/space
• An abscess or other evidence of infection involving the organ/space that is found on direct examination, during reoperation or by histopathologic or radiologic examination