Device and surgical procedure-related infections in Canadian acute care hospitals

Abstract

Background: Healthcare-associated infections (HAIs) are a significant healthcare burden in Canada. National surveillance of HAIs at sentinel acute care hospitals is conducted by the Canadian Nosocomial Infection Surveillance Program.

Objective: This article describes device and surgical procedure-related HAI epidemiology in Canada from 2018 to 2022.

Methods: Data were collected from over 60 Canadian sentinel acute care hospitals between January 1, 2018, and December 31, 2022, for central line-associated bloodstream infections (CLABSIs), hip and knee surgical site infections (SSIs), cerebrospinal fluid shunt (CSF) SSIs and paediatric cardiac SSIs. Case counts, rates, patient and hospital characteristics, pathogen distributions and antimicrobial resistance data are presented.

Results: Between 2018 and 2022, 2,258 device-related infections and 987 surgical procedure-related infections were reported. A significant rate increase was observed in adult mixed intensive care unit CLABSIs (1.07–1.93 infections per 1,000 line days, p=0.05) and a non-significant rate increase was observed in SSIs following knee arthroplasty (0.31–0.42 infections per 100 surgeries, p=0.45). A fluctuating rate trend was observed in CSF shunt SSIs over the time period and a significant rate decrease in paediatric cardiac SSIs was observed (68%, from 7.5–2.4 infections per 100 surgeries, p=0.01). The most commonly identified pathogens were coagulase-negative staphylococci (22.8%) among CLABSIs and Staphylococcus aureus (42%) among SSIs.

Conclusion: Epidemiological and microbiological trends among selected device and surgical procedure-related HAIs are essential for benchmarking infection rates nationally and internationally, identifying any changes in infection rates or antimicrobial resistance patterns and helping inform hospital infection prevention and control and antimicrobial stewardship policies and programs.

Introduction

Healthcare-associated infections (HAIs) contribute to excess patient morbidity and mortality, leading to increased healthcare costs, longer hospital stays and increased antimicrobial resistance ^{Footnote 1}. Healthcare-associated infections may occur during the use of invasive devices and following surgical procedures ^{Footnote 2}. More specifically, surgical procedure-related infections are among the most prevalent HAIs and are responsible for a longer hospitalization of approximately seven to 11 days ^{Footnote 3}. Device and surgical procedure-related infections are also associated with a high-cost burden, accounting for almost $50,000 per central line-associated bloodstream infections (CLABSIs) case and $28,000 per surgical site infection (SSI) case ^{Footnote 4}.

A 2017 point prevalence study in Canadian sentinel acute care hospitals found that device and surgical procedure-related infections accounted for 35.6% of all reported HAIs ^{Footnote 5}. Central line-associated bloodstream infections accounted for 21.2% of device and surgical procedure-related infections while prosthetic implants accounted for 19.4% ^{Footnote 5}. The risk of device and surgical procedure-related infections is associated with patient demographics and comorbidities, in addition to the type of hospital in which the patient received care ^{Footnote 6Footnote 7Footnote 8}.

Understanding the epidemiology of device and surgical procedure-related HAIs is essential to provide benchmark rates over time, which help to inform effective antimicrobial stewardship and infection prevention and control measures. In addition, the collection and analysis of antimicrobial susceptibility data are important to inform the appropriate use of antimicrobials and help reduce antimicrobial resistance ^{Footnote 9}. This report provides an epidemiological overview of select device and surgical procedure-related HAIs from 2018 to 2022 in over 60 hospitals participating in the Canadian Nosocomial Infection Surveillance Program (CNISP).

Methods

Design

Since its establishment in 1994, CNISP has conducted national HAI surveillance at sentinel acute care hospitals across Canada, in collaboration with the Public Health Agency of Canada and the Association of Medical Microbiology and Infectious Disease Canada (AMMI Canada). Data are presented for the following device and surgical procedure-related HAIs: CLABSIs; hip and knee arthroplasty SSIs; cerebrospinal fluid (CSF) shunt SSIs; and paediatric cardiac SSIs.

Case definitions

Device and surgical procedure-related HAIs were defined according to standardized protocols and case definitions (see Appendix). Complex infections, defined as deep incisional and organ/space, were included in hip and knee SSI surveillance, while CLABSIs identified in intensive care unit (ICU) settings were included in CLABSI surveillance. The adult mixed ICU, adult cardiovascular surgery intensive care unit (CVICU), paediatric intensive care unit (PICU) and neonatal intensive care unit (NICU) were included as eligible ICU settings. Adult mixed intensive care units included any adult ICU with a mix of patient types as part of the ICU patient mix (i.e., medical/surgical, surgical/trauma, burn/trauma, medical/neurosurgical).

Data source

Epidemiological data for device and surgical procedure-related infections identified between January 1, 2018, and December 31, 2022 (using surgery date for surgical site infections and date of positive blood culture for CLABSIs) were submitted by participating hospitals using standardized data collection forms. Hospital participation varied by surveillance project and year. Data submission and case identification were supported by training sessions and periodic evaluations of data quality.

Statistical analysis

To calculate hip and knee SSI, CSF shunt SSI and paediatric cardiac SSI rates, the number of cases were divided by the number of surgical procedures performed (multiplied by 100). To calculate CLABSI rates, the number of cases was divided by line day denominators (multiplied by 1,000). Neonatal intensive care unit CLABSI rates stratified by birth weight category were not included in this report. To calculate proportions of pathogens, the number of pathogens were divided by the total number of identified pathogens. Denominators may vary, as missing and incomplete data were excluded from analyses. Median and interquartile ranges (IQR) were calculated for continuous variables. Trends over time were tested using the Mann-Kendall test. Significance testing was two-tailed and differences were considered significant at a p-value of ≤0.05. Analyses were conducted using R version 4.1.2 and SAS 9.4.

Results

Over 60 hospitals contributed device and surgical procedure-related infection data to CNISP between 2018 and 2022 (Table 1), with medium-sized (n=201−499 beds) adult hospitals (n=16 sites, 25%) being the most common (data not shown). Overall, 2,258 device-related infections and 987 surgical procedure-related infections were reported. Among all SSIs reported (n=987), hip and knee infections represented 68% (n=667) of these types of infections.

A total of 2,496 pathogens were identified from device-related infections and 1,056 pathogens from surgical procedure-related cases between 2018 and 2022. Of the identified pathogens for CLABSIs, 61% were gram-positive, 24% were gram-negative and 15% were fungal. Of the identified pathogens for SSIs, 79% were gram-positive, 19% were gram-negative and 1.5% were fungal. Coagulase-negative staphylococci (CoNS) and Staphylococcus aureus were the most frequently reported pathogens for CLABSIs and SSIs, respectively (Table 2). From 2018 to 2022, the proportion of methicillin-resistant S. aureus (MRSA) was 16% for CLABSIs and 11% for SSIs (data not shown).

Central line-associated bloodstream infections

A total of 2,258 CLABSIs were reported between 2018 and 2022, with the majority occurring in adult mixed ICUs (n=1,411, 62.5%) and NICUs (n=456, 20.2%). Overall, NICUs had the highest rates of CLABSIs between 2018 and 2022 (1.75 infections per 1,000 line days), followed by adult mixed ICUs (1.66 infections per 1,000 line days), PICUs (1.65 infections per 1,000 line days) and adult CVICUs (0.82 infections per 1,000 line days) (Table A1).

From 2018 to 2022, CLABSI rates fluctuated in NICUs and PICUs, while CLABSI rates in adult mixed ICUs increased significantly by 80% (1.07–1.93 infections per 1,000 line days, p=0.05) (Figure 1). Though rates of CLABSI in adult CVICUs were low overall, adult CVICU CLABSI rates increased 28% from 2018 to 2021 (0.78–1.0 infections per 1,000 line days) before decreasing 20% to 0.83 infections per 1,000 line days in 2022.

Figure 1 - Text description

Figure 1

Year	Adult mixed ICU	Adult CVICU	NICU	PICU
2018	1.07	0.78	1.77	1.92
2019	1.42	0.61	2.01	1.75
2020	1.74	0.95	1.54	1.7
2021	2.11	1	1.9	1.32
2022	1.93	0.83	1.53	1.61
Overall	1.66	0.82	1.75	1.65

Among CLABSIs identified in adult mixed ICUs, the median age was 60 years (IQR=47–69 years), with males representing the majority of cases (66%). All-cause mortality within 30 days following the first positive culture, for adult mixed ICU CLABSI patients was 32% (n=452/1,411). Among CLABSIs identified in adult CVICUs, the median age was 65 years (IQR=51–72 years), with males representing 72% of cases. Within 30 days following the first positive culture, all-cause mortality for adult CVICU CLABSI patients was 29.1% (n=39/134). Among CLABSIs identified in PICUs, the median age was seven months (IQR=3−36 months), with males representing 58% of cases. Within 30 days following the first positive culture, all-cause mortality for PICU CLABSI patients was 8.9% (n=23/257). Among CLABSIs identified in NICUs, the median age at first positive culture was 19 days (IQR=9−41 days). Males represented 59% of NICU cases and all-cause mortality within 30 days of positive culture was 12% (n=53/456).

The most commonly identified pathogens among CLABSIs overall were CoNS and Enterococcus spp. (22.8% and 21.5%, respectively), which aligned with the most commonly identified pathogens among adult mixed ICUs and adult CVICUs. Among PICU and NICU CLABSIs, CoNS and S. aureus were the most commonly identified pathogens (data not shown). Among CLABSIs identified with Serratia spp., most were in the adult mixed ICU (54.3%, n=25/46), followed by NICU (17.4%, n=8/46), PICU (17.4%, n=8/46) and adult CVICUs (10.9%, n=5/46).

Hip and knee surgical site infections

A total of 667 complex hip and knee SSIs were reported between 2018 and 2022, of which the majority were hip arthroplasties (n=440, 66%). Among hip and knee SSIs, 55% (n=242) were organ/space infections and 45% (n=198) were deep incisional infections (Table 3). From 2018 to 2022, knee SSI rates increased non-significantly by 35.5% (0.31–0.42 infections per 100 surgeries, p=0.45) while hip SSI rates fluctuated between 0.75 and 0.88 infections per 100 surgeries (p=0.33) (Figure 2). During the COVID-19 pandemic in 2020, knee SSI rates remained stable while hip SSI rates decreased by 40%, compared to 2019. In 2022, both hip and knee SSI rates increased to 0.72 and 0.42 infections per 100 surgeries respectively, returning to rates observed in the pre-pandemic period (Figure 2 and Table A2).

Figure 2 - Text description

Figure 2

Year	Hip	Knee
2018	0.88	0.31
2019	0.78	0.34
2020	0.47	0.34
2021	0.66	0.27
2022	0.75	0.42
Overall	0.71	0.34

The median patient age was 68 years (IQR=59–75 years) for hip SSIs and 66 years (IQR=59–74 years) for knee SSIs. The median time from procedure to hip and knee infections was 22 days (IQR=15–34 days) and 24 days (IQR=16–39 days), respectively. For data collected between 2018 and 2022, the median length of stay was three days (IQR=1–7 days) for hip SSIs and two days (IQR=1–4 days) for knee SSIs. Most patients (84%, n=552/661) with an SSI following hip or knee arthroplasty were readmitted and 66% (n=431/652) required revision surgery. Within 30 days after first positive culture, five all-cause deaths (2.1%, n=9/427) were reported among patients with a complex SSI following a hip arthroplasty while zero all-cause deaths were reported among patients with a knee arthroplasty SSI. Among hip and knee SSI cases, S. aureus and CoNS were the most commonly identified pathogens at 38% and 19%, respectively, and did not differ by deep or organ/space infection type (data not shown).

Cerebrospinal fluid shunt surgical site infections

Between 2018 and 2022, 151 CSF shunt SSIs were reported, with an overall rate of 2.9 infections per 100 surgeries (range: 1.7–3.82 infections per 100 surgeries, Table A3). Paediatric and adult/mixed hospitals infection rates were not significantly different at 3.2 and 2.5 infections per 100 surgeries, respectively (p=0.17). Cerebrospinal fluid shunt SSI rates in all hospitals decreased throughout the COVID-19 pandemic in 2020 and 2021 (Figure 3), then increased by 41% in 2022 (2.3 infections per 100 surgeries in 2021 to 3.3 infections per 100 surgeries in 2022). Paediatric hospital CSF shunt SSI rates decreased by 39% from 2019 to 2021, before increasing again to 4.3 infections per 100 surgeries in 2022, in keeping with the fluctuating rate trend observed since 2011 (data not shown).

Figure 3 - Text description

Figure 3

Year	Adult and mixed hospitals	Paediatric hospitals	All hospitals
2018	1.84	1.56	1.70
2019	3.25	4.55	3.82
2020	2.17	2.97	2.73
2021	1.75	2.79	2.31
2022	2.14	4.26	3.25
Overall	2.50	3.15	2.85

More than half of CSF shunt SSIs (53.6%, n=81/151) were identified from new surgeries while 46.4% (n=70/151) were identified from revision surgeries. The median age was 47 years (IQR=36–62 years) for adult patients and three years (IQR=0.4–9 years) for paediatric patients. Females represented 54% (n=82/151) of cases and median time from surgery to infection was 19 days (IQR=10–40 days). The most commonly identified pathogens from CSF shunt SSIs were CoNS and S. aureus (36% and 30% of identified pathogens, respectively). Outcome data were not collected for CSF shunt SSI surveillance.

Paediatric cardiac surgical site infections

A total of 169 paediatric cardiac SSIs were reported between 2018 and 2022 (Table 4). Most of these SSIs were superficial infections (62%), followed by organ/space infections (30%). Overall, the average paediatric cardiac SSI rate was 3.9 infections per 100 surgeries (Table A4). From 2018 to 2022, rates decreased significantly by 68% and consistently, from 7.5 to 2.4 infections per 100 surgeries (p=0.01) (Figure 4). The high rate in 2018 was caused by outlier cases attributable to two hospitals.

Figure 4 - Text description

Figure 4

Year	Rate
2018	7.46
2019	5.04
2020	3.46
2021	3.31
2022	2.38
Overall	3.93

The median age of patients with a paediatric cardiac SSI was 40 days (IQR=6–246 days) and the median time from surgery to onset date of infection was 16 days (IQR=8–24 days). Among the three deaths reported within 30 days of infection onset (1.8% of cases), one death was unrelated to the paediatric cardiac SSI, while two deaths were attributable to the paediatric cardiac SSI. Staphylococcus aureus and CoNS were the most commonly identified pathogens from paediatric cardiac SSIs (57% and 16% 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 Figure 5 and Figure 6. The S. aureus isolates were resistant to cloxacillin/oxacillin (MRSA) in 15% (n=28/189) of CLABSIs and 12% (n=40/337) of SSIs. Meropenem resistance ranged from 3% to 38% in gram-negative pathogens identified from CLABSIs. No meropenem resistance was observed among pathogens isolated from SSIs. Seventy-six vancomycin-resistant Enterococci were identified among CLABSIs (23%).

Figure 5 - Text description

Figure 5

Category	Pathogen	Antimicrobial	Percent resistant (%)	Percent of isolates reported (%)
Fungi	Candida albicans	Amphotericin B	0Figure 5 footnote e	28
Fungi	Candida albicans	Caspofungin	0Figure 5 footnote e	37
Fungi	Candida albicans	Fluconazole	2	97
Fungi	Candida albicans	Micafungin	0Figure 5 footnote e	43
Fungi	Candida albicans	Voriconazole	0Figure 5 footnote e	54
Fungi	Candida parapsilosis	Fluconazole	15	97
Gram-negative	Enterobacter spp.	Ampicillin	R	-
Gram-negative	Enterobacter spp.	Ciprofloxacin	3Figure 5 footnote e	85
Gram-negative	Enterobacter spp.	Ceftriaxone	61Figure 5 footnote e	74
Gram-negative	Enterobacter spp.	Cefazolin	R	-
Gram-negative	Enterobacter spp.	Ertapenem	15Figure 5 footnote e	39
Gram-negative	Enterobacter spp.	GentamicinFigure 5 footnote d	6Figure 5 footnote e	86
Gram-negative	Enterobacter spp.	Meropenem	3Figure 5 footnote e	69
Gram-negative	Enterobacter spp.	Trimethoprim/sulfamethoxazole	16Figure 5 footnote e	74
Gram-negative	Enterobacter spp.	Tobramycin	4Figure 5 footnote e	66
Gram-negative	Enterobacter spp.	Piperacillin/tazobactam	40Figure 5 footnote e	71
Gram-negative	Escherichia coli	Amoxicillin/clavulanic acid	14Figure 5 footnote e	32
Gram-negative	Escherichia coli	Ampicillin	73	95
Gram-negative	Escherichia coli	Ciprofloxacin	42Figure 5 footnote e	63
Gram-negative	Escherichia coli	Ceftriaxone	25Figure 5 footnote e	84
Gram-negative	Escherichia coli	Cefazolin	40Figure 5 footnote e	79
Gram-negative	Escherichia coli	Ertapenem	3Figure 5 footnote e	35
Gram-negative	Escherichia coli	GentamicinFigure 5 footnote d	19	95
Gram-negative	Escherichia coli	Meropenem	4Figure 5 footnote e	50
Gram-negative	Escherichia coli	Trimethoprim/sulfamethoxazole	48Figure 5 footnote e	85
Gram-negative	Escherichia coli	Tobramycin	12Figure 5 footnote e	78
Gram-negative	Escherichia coli	Piperacillin/tazobactam	18Figure 5 footnote e	86
Gram-negative	Klebsiella spp.	Amoxicillin/clavulanic acid	13Figure 5 footnote e	33
Gram-negative	Klebsiella spp.	Ampicillin	R	-
Gram-negative	Klebsiella spp.	Ciprofloxacin	16Figure 5 footnote e	76
Gram-negative	Klebsiella spp.	Ceftriaxone	22Figure 5 footnote e	76
Gram-negative	Klebsiella spp.	Cefazolin	40Figure 5 footnote e	77
Gram-negative	Klebsiella spp.	Ertapenem	6Figure 5 footnote e	28
Gram-negative	Klebsiella spp.	GentamicinFigure 5 footnote d	12	93
Gram-negative	Klebsiella spp.	Meropenem	9Figure 5 footnote e	50
Gram-negative	Klebsiella spp.	Trimethoprim/sulfamethoxazole	17Figure 5 footnote e	87
Gram-negative	Klebsiella spp.	Tobramycin	8Figure 5 footnote e	74
Gram-negative	Klebsiella spp.	Piperacillin/tazobactam	16Figure 5 footnote e	74
Gram-negative	Pseudomonas spp.	Ciprofloxacin	12Figure 5 footnote e	89
Gram-negative	Pseudomonas spp.	GentamicinFigure 5 footnote d	2Figure 5 footnote e	84
Gram-negative	Pseudomonas spp.	Meropenem	38Figure 5 footnote e	57
Gram-negative	Pseudomonas spp.	Tobramycin	2Figure 5 footnote e	80
Gram-negative	Pseudomonas spp.	Piperacillin/tazobactam	13Figure 5 footnote e	80
Gram-negative	Serratia spp.	Ampicillin	R	-
Gram-negative	Serratia spp.	Ciprofloxacin	7Figure 5 footnote e	73
Gram-negative	Serratia spp.	GentamicinFigure 5 footnote d	0Figure 5 footnote e	81
Gram-negative	Serratia spp.	Trimethoprim/sulfamethoxazole	0Figure 5 footnote e	85
Gram-positive	Bacillus spp.	Vancomycin	0	97
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Clindamycin	68Figure 5 footnote e	51
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Cloxacillin	87Figure 5 footnote e	89
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Cefazolin	84Figure 5 footnote e	47
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Erythromycin	83Figure 5 footnote e	30
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	GentamicinFigure 5 footnote d	38Figure 5 footnote e	12
Gram-positive	Coagulase-negative staphylococci	Linezolid	0Figure 5 footnote e	14
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Benzylpenicillin	94Figure 5 footnote e	17
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Rifampicin	2Figure 5 footnote e	23
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Trimethoprim/sulfamethoxazole	55Figure 5 footnote e	60
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Tetracycline	14Figure 5 footnote e	9
Gram-positive	Coagulase-negative staphylococciFigure 5 footnote b	Vancomycin	0Figure 5 footnote e	88
Gram-positive	Enterococcus   spp.	Ampicillin	40	96
Gram-positive	Enterococcus  spp.	Daptomycin	0Figure 5 footnote e	7
Gram-positive	Enterococcus  spp.	GentamicinFigure 5 footnote d	14Figure 5 footnote e	40
Gram-positive	Enterococcus  spp.	Linezolid	5Figure 5 footnote e	24
Gram-positive	Enterococcus  spp.	Benzylpenicillin	50Figure 5 footnote e	15
Gram-positive	Enterococcus  spp.	Vancomycin	23Figure 5 footnote e	82
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Clindamycin	27Figure 5 footnote e	50
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Cloxacillin	15Figure 5 footnote e	83
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Cefazolin	14Figure 5 footnote e	57
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Erythromycin	23Figure 5 footnote e	36
Gram-positive	Staphylococcus aureusFigure 5 footnote c	GentamicinFigure 5 footnote d	3Figure 5 footnote e	16
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Linezolid	0Figure 5 footnote e	14
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Benzylpenicillin	82Figure 5 footnote e	20
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Rifampicin	0Figure 5 footnote e	17
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Trimethoprim/sulfamethoxazole	3Figure 5 footnote e	48
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Tetracycline	0Figure 5 footnote e	13
Gram-positive	Staphylococcus aureusFigure 5 footnote c	Vancomycin	0Figure 5 footnote e	44
Gram-positive	Streptococcus spp.	Benzylpenicillin	0	91

Figure 6 - Text description

Figure 6

Category	Pathogen	Antimicrobial	Percent resistant (%)	Percent of isolates reported (%)
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Cefazolin	68Figure 6 footnote e	59.38
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Clindamycin	19Figure 6 footnote e	50.86
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Cloxacillin	65	93.68
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Erythromycin	43Figure 6 footnote e	39.08
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Rifampicin	0Figure 6 footnote e	26.44
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Trimethoprim/sulfamethoxazole	26Figure 6 footnote e	46.55
Gram-positive	Coagulase-negative staphylococciFigure 6 footnote b	Vancomycin	0Figure 6 footnote e	73.71
Gram-positive	Enterococcus  spp.	Ampicillin	3	92.11
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Benzylpenicillin	86Figure 6 footnote e	11.59
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Cefazolin	12Figure 6 footnote e	60.5
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Clindamycin	22v	65.65
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Cloxacillin	12	93.35
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Erythromycin	31Figure 6 footnote e	42.11
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Rifampicin	0Figure 6 footnote e	21.88
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Trimethoprim/sulfamethoxazole	1Figure 6 footnote e	59.28
Gram-positive	Staphylococcus aureusFigure 6 footnote c	Vancomycin	1Figure 6 footnote e	34.9
Gram-positive	Streptococcus spp.Figure 6 footnote c	Benzylpenicillin	0Figure 6 footnote e	83.02
Gram-positive	Streptococcus spp.Figure 6 footnote c	Clindamycin	10Figure 6 footnote e	75

Discussion

This report summarizes 2,258 device-related infections and 987 surgical procedure-related infections identified over five years of surveillance (2018–2022) from 64 hospitals across Canada. During this time, rates of device and surgical procedure-related HAIs have increased significantly by 80% for adult mixed ICU CLABSIs and non-significantly by 36% for knee SSIs. The COVID-19 pandemic has had a varied impact on the rates of device and surgical procedure-related HAIs ^{Footnote 10}. In Canada, preliminary investigations suggest that the COVID-19 pandemic had an immediate but unsustained impact on HAI rate trends ^{Footnote 11}. Rates of SSIs in the CNISP network initially decreased in 2020 during the COVID-19 pandemic, when elective surgeries were postponed, before increasing towards pre-pandemic levels in 2021. Ongoing investigations continue to assess the influence of pandemic-related factors such as changes in infection control practices, screening, laboratory testing and antimicrobial stewardship on the observed rates of HAIs.

Central line-associated bloodstream infections

Where comparable data were available, the rates of CLABSI in adult ICUs (overall rate: 0.82 and 1.66 infections per 1,000 line days for CVICUs and mixed ICUs, respectively) were lower than those in the United Kingdom but higher than those in Western Australia ^{Footnote 12Footnote 13Footnote 14}. In the United Kingdom, 2021 and 2022 rates of CLABSI in the adult and cardiac ICU were 2.5 and 1.6 infections per 1,000 line days, respectively ^{Footnote 14}. In Western Australia, CLABSI rates in adult ICU settings ranged from 0.0 to 0.8 infections per 1,000 line days between 2018 and 2022 and may be lower than levels in Canada due to differences in surveillance methodologies including the number and type of hospitals under surveillance ^{Footnote 12}. Compared to CNISP adult mixed ICU CLABSI rates, a European Centre for Disease Prevention and Control report noted similar or higher 2019 rates in France and Italy (1.4–3.8 infections per 1,000 line days), while Austrian and Lithuanian CLABSI rates were lower (0.1–0.2 infections per 1,000 line days) ^{Footnote 15}.

Rates of CLABSIs in the NICU and PICU fluctuated from 2018 to 2022 but were higher overall (1.75 and 1.65 infections per 1,000 line days, respectively) compared to CLABSI rates in adult mixed ICUs and adult CVICUs (1.66 and 0.82 infections per 1,000 line days, respectively). Data available from the United States from 2018 to 2022 indicate the standardized incidence ratios (defined as the ratio of observed number of infections compared to the 2015 baseline) have reported similar fluctuating trends and have experienced a 9% decrease in CLABSI rates between 2021 and 2022 ^{Footnote 16Footnote 17Footnote 18Footnote 19Footnote 20}. Higher rates of CLABSIs have been seen in other limited resource settings compared to those observed in the CNISP network; a large surveillance study of ICUs in 45 countries from Latin America, Europe, Eastern Mediterranean, Southeast Asia and Western Pacific World Health Organization regions reported pooled mean CLABSI rates of 5.37 per 1,000 line days in PICUs (57 participating ICUs) and 4.66 in medical/surgical adult ICUs (182 participating ICUs) between January 2015 and December 2020 ^{Footnote 21}.

Surgical site infections

Among SSIs included in this surveillance report, hip and knee SSIs were the most prevalent. Hip SSI rates fluctuated across reporting years, while knee SSI rates increased non-significantly. Surveillance from the United Kingdom indicates hip and knee SSI rates slightly increased for 2021 and 2022, after remaining stable for 10 years ^{Footnote 22}. Compared to CNISP data, hip and knee SSI rates reported in Southern Australia were higher overall and have also seen increases in recent years; hip SSI rates increased from 2018 to 2020 (1.80–1.91 infections per 100 procedures), while knee SSI rates increased from 0.79 to 0.88 infections per 100 procedures, during the same time period ^{Footnote 23}. In accordance with results from other regions, the most common pathogens among hip and knee SSIs were S. aureus and CoNS, likely attributed to the contamination of implant devices by the patient’s endogenous skin flora ^{Footnote 24Footnote 25}. Higher median age of patients with hip and knee SSIs relate to the older age of patients requiring joint replacements and the increased likelihood of surgical complications ^{Footnote 26}. Our data indicate that frequent readmission and revision surgeries are required for SSIs, both of which place high economic and resource burdens on the Canadian healthcare system, consistent with other studies from the United States, Australia and the United Kingdom ^{Footnote 27Footnote 28Footnote 29Footnote 30}.

The overall rate of SSIs from CSF shunts was 2.85 per 100 surgeries from 2018 to 2022. Stratification of CSF shunt SSI data by paediatric and adult/mixed hospitals showed that from 2018 to 2022, adult rates (2.5 infections per 100 surgeries) and paediatric rates (3.2 infections per 100 surgeries) were not significantly different. Data from historical CNISP surveillance shows a fluctuating trend in CSF shunt SSI rates from 2011 to 2020 ^{Footnote 31}. Compared to historical data, CSF shunt SSI rates among paediatric patients from 2018 to 2022 (3.2%) were lower than those from 2000 to 2002 (4.9%), signifying a decrease in SSI rates among paediatric populations ^{Footnote 32}. The rate of CSF shunt SSI among adult patients from 2018 to 2022 (2.5%) was also lower compared to that of 2000 to 2002 (3.2%) ^{Footnote 32}. A national survey from 2017 conducted in England showed a mean brain shunt infection rate of 1.9% (range: 0–4.4%), which is lower than what we observed, although there may be variations in the definitions and methodologies of rate calculation ^{Footnote 33}.

The overall rate of paediatric cardiac SSI between 2018 and 2022 was 3.93 per 100 surgeries. The relatively high rate of paediatric cardiac SSI in 2018 should be interpreted with caution, as rates may fluctuate due to the limited number of annual cases. Literature regarding paediatric cardiac SSI rates is limited; however, a pre-post intervention study from 2013 to 2017 has reported successful reduction in paediatric cardiac SSI rates from 3.4 to 0.9 per 100 surgeries in a quaternary, paediatric academic center in California following the implementation of a postoperative SSI reduction care bundle ^{Footnote 34}.

Antibiogram

The percentage of S. aureus isolates that were MRSA among CLABSIs (15%) and SSIs (12%) was lower in the CNISP network compared to data reported by Centers for Disease Control and Prevention where 44% and 38% of S. aureus isolates were MRSA for CLABSIs and SSIs, respectively ^{Footnote 35}.

Of the identified Enterococcus spp. in CLABSIs, 23% were vancomycin-resistant Enterococci (VRE). From National Healthcare Safety Network surveillance in the United States, 73% of Enterococcus faecium and 4% of Enterococcus faecalis pathogens identified from CLABSIs in ICUs were VRE in 2021 ^{Footnote 36}. Meropenem resistance was low in most gram-negative pathogens identified among CLABSIs and SSIs (0%–8%) in the CNISP network, and similar to carbapenem resistance levels reported in the United States in 2021 (5% among Klebsiella spp.; 6% among Enterobacter spp.; and 0.8% among tested E. coli isolates) ^{Footnote 37}.

However, among Pseudomonas spp. identified in CLABSIs, meropenem resistance was 38%, which is higher than levels reported in the United States (21% carbapenem-resistant Pseudomonas aeruginosa among CLABSIs in 2021) ^{Footnote 38Footnote 39}. Overall, antibiogram patterns observed in the CNISP network may differ compared to other countries due to differences in surveillance methodologies, antimicrobial stewardship practices, types of hospitals or patient populations under surveillance and differences in circulating molecular strain types.

Strengths and limitations

The main strength of CNISP surveillance is the standardized collection of detailed epidemiological and molecular linked data from a large representative network of sentinel hospitals across Canada. From 2018 to 2022, CNISP coverage of Canadian acute care beds has increased from 32% to 35%, including increased representativeness in northern, community, rural, and Indigenous populations. To further improve representativeness, CNISP has launched a simplified dataset accessible to all acute care hospitals across Canada to collect and visualize annual HAI rate data. The number of hospitals participating in each HAI surveillance project differed and 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 subset of CLABSIs occurring in the hospital. Further, differences in surveillance protocols and case definitions limit comparison with data from other countries. Studies are ongoing to assess the impact of the COVID-19 pandemic on device and surgical procedure-related HAIs and antimicrobial resistance.

Conclusion

This report provides an updated summary of rates, pathogen distributions and antimicrobial resistance patterns among select device and surgical procedure-related HAIs and relevant pathogens. The collection and analysis of national surveillance data are important to understanding and reducing the burden of device and surgical procedure-related HAIs. These data provide benchmark rates for national and international comparison and inform 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: Vancouver General Hospital (VGH), Vancouver, British Columbia (BC); Richmond General Hospital, Richmond, BC; UBC Hospital, Vancouver, BC; Lion’s Gate, North Vancouver, BC; Powell River General Hospital, Powell River, BC; Sechelt Hospital (formerly St. Mary’s), Sechelt, BC; Squamish General Hospital, Squamish, BC; Victoria General Hospital, Victoria, BC; Royal Jubilee Hospital, Victoria, BC; Nanaimo Regional General Hospital, Nanaimo, BC; BC Women’s Hospital, Vancouver, BC; BC Children’s Hospital, Vancouver, BC; Kelowna General Hospital, Kelowna, BC; Penticton Regional Hospital, Penticton, BC; University Hospital of Northern BC, Prince George, BC; Peter Lougheed Centre, Calgary, Alberta (AB); Rockyview General Hospital, Calgary, AB; South Health Campus, Calgary, AB; Foothills Medical Centre, Calgary, AB; Alberta Children’s Hospital, Calgary, AB; University of Alberta Hospital, Edmonton, AB; Stollery Children’s Hospital, Edmonton, AB; Royal University Hospital, Saskatoon, Saskatchewan (SK); Regina General Hospital, Regina, SK; Pasqua Hospital, Regina, SK; Moose Jaw Hospital, SK; St. Paul’s Hospital, Saskatoon, SK; Health Sciences Centre-Winnipeg, Winnipeg, Manitoba (MB); University of Manitoba Children’s Hospital, Winnipeg, MB; Children’s Hospital of Western Ontario, London, Ontario (ON); St. Michael’s Hospital, Toronto, ON; Victoria Hospital, London, ON; University Hospital, London, ON; Toronto General Hospital, Toronto, ON; Toronto Western Hospital, Toronto, ON; Princess Margaret, Toronto, ON; Mount Sinai Hospital, Toronto, ON; Bridgepoint Active Healthcare, Toronto, ON; Sunnybrook Hospital, Toronto, ON; Kingston General Hospital, Kingston, ON; The Hospital for Sick Children, Toronto, ON; McMaster Children’s Hospital, Hamilton, ON; St. Joseph’s Healthcare, Hamilton, ON; Jurvinski Hospital and Cancer Center, Hamilton, ON; Hamilton Health Sciences General Site, Hamilton, ON; The Ottawa Hospital Civic Campus, Ottawa, ON; The Ottawa Hospital General Campus, Ottawa, ON; University of Ottawa Heart Institute, Ottawa, ON; Children’s Hospital of Eastern Ontario (CHEO), Ottawa, ON; North York General Hospital, Toronto, ON; Sudbury Regional Hospital, Sudbury, ON; Temiskaming Hospital, Temiskaming Shores, ON; SMBD - Jewish General Hospital, Montréal, Québec (QC); Lachine General Hospital, Lachine, QC; Montreal Children’s Hospital, Montréal, QC; Hôpital Maisonneuve-Rosemont, Montréal, QC; Hôtel-Dieu de Québec, QC; Centre hospitalier de l’Université de Montréal, Montréal, QC; Montreal General Hospital, Montréal, QC; Centre Hospitalier Universitaire Sainte-Justine, Montréal, QC; Royal Victoria Hospital, Montréal, QC; Montreal Neurological Institute, Montréal, QC; The Moncton Hospital, Moncton, New Brunswick (NB); Halifax Infirmary, Halifax, Nova Scotia (NS); Victoria General, Halifax, NS; Rehabilitation Centre, Halifax, NS; Veterans Memorial Building, Halifax, NS; Dartmouth General Hospital, Halifax, NS; IWK Health Centre, Halifax, NS; General Hospital & Miller Centre, St. John’s, Newfoundland and Labrador (NL); Burin Peninsula Health Care Centre, Burin, NL; Carbonear General Hospital, Carbonear, NL; Dr. G.B. Cross Memorial Hospital, Clarenville, NL; Janeway Children’s Hospital and Rehabilitation Centre, St. John’s, NL; St. Clare’s Mercy Hospital, St. John’s, NL; Sir Thomas Roddick Hospital, Stephenville, NL; Western Memorial Regional Hospital, Corner Brook, NL; Central Newfoundland Regional Health Centre, Grand Falls-Windsor, NL; James Paton Memorial Hospital, Gander, NL; Dr. Y.K. Jeon Kittiwake Health Centre, New-Wes-Valley, NL; Fogo Island Health Centre, Fogo, NL; Notre Dame Bay Memorial Health Centre, Twillingate, NL; Connaigre Peninsula Health Centre, Harbour Breton, NL; A. M. Guy Health Centre, Buchans, NL; Green Bay Health Centre, Springdale, NL; Baie Verte Peninsula Health Centre, Baie Verte, NL; Queen Elizabeth Hospital, Charlottetown, Prince Edward Island (PE); Prince County Hospital, Summerside, PE; Qikiqtani General Hospital, Nunavut.

Thank you to the staff at Public Health Agency of Canada in the Centre for Communicable Diseases and Infection Control, Ottawa, ON (J Bartoszko, J Cayen, D Lee, C Lybeck, C McClellan, E McGill, R Mitchell, A Neitzel, A-K Nguyen, N Papayiannakis, L Pelude, A Silva, Z Suleman, O Varsaneux, ZL Zhou) and the National Microbiology Laboratory, Winnipeg, MB (G Golding, M Mulvey, J Campbell, T Du, M McCracken, L Mataseje, A Bharat, R Edirmanasinghe, R Hizon, S Ahmed, K Fakharuddin, D Spreitzer and D Boyd).

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 (CLABSIs) 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 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