Implementation of standardised surveillance for Clostridium difficile infections in Australia: initial report from the Victorian Healthcare Associated Infection Surveillance System

Use of a Victorian statewide surveillance program to evaluate the burden of healthcare-associated Staphylococcus aureus bacteraemia and Clostridioides difficile infection in patients with cancer

BACKGROUND

Patients with cancer are at high risk for infection, but the epidemiology of healthcare-associated Staphylococcus aureus bacteraemia (HA-SAB) and Clostridioides difficile infection (HA-CDI) in Australian cancer patients has not previously been reported.

AIMS

To compare the cumulative aggregate incidence and time trends of HA-SAB and HA-CDI in a predefined cancer cohort with a mixed statewide patient population in Victoria, Australia.

METHODS

All SAB and CDI events in patients admitted to Victorian healthcare facilities between 1^st July 2010 and 31^st December 2018 were submitted to the Victorian Healthcare Associated Infection Surveillance System Coordinating Centre. Descriptive analyses and multilevel mixed-effects Poisson regression modelling were applied to a standardised data extract.

RESULTS

In total, 10,608 and 13,118 SAB and CDI events were reported across 139 Victorian healthcare facilities, respectively. Of these, 89 (85%) and 279 (88%) were healthcare-associated in the cancer cohort compared to 34% (3,561/10,503) and 66% (8,403/12,802) in the statewide cohort. The aggregate incidence was more than two-fold higher in the cancer compared to the statewide cohort for HA-SAB (2.25 [95% CI: 1.74-2.77] vs. 1.11 [95% CI: 1.07-1.15] HA-SABs/10,000 OBDs) and three-fold higher for HA-CDI (6.26 [95% CI: 5.12-7.41] vs. 2.31 [95% CI: 2.21-2.42] HA-CDIs/10,000 OBDs). Higher quarterly diminishing rates were observed in the cancer cohort than the statewide data for both infections.

CONCLUSIONS

Our findings demonstrate a higher burden of HA-SAB and HA-CDI in a cancer cohort when compared with state data and highlight the need for cancer-specific targets and benchmarks to meaningfully support quality improvement. This article is protected by copyright. All rights reserved.

Clostridium difficile Infection

Clostridium difficile is an anaerobic, Gram-positive, spore-forming, toxin-secreting bacillus that has long been recognized to be the most common etiologic pathogen of antibiotic-associated diarrhea. C. difficile infection (CDI) is now the most common cause of health care-associated infections in the United States and accounts for 12% of these infections (Magill SS et al., N Engl J Med370:1198-1208, 2014). Among emerging pathogens of public health importance in the United States, CDI has the highest population-based incidence, estimated at 147 per 100,000 (Lessa FC et al., N Engl J Med372:825-834, 2015). In a report on antimicrobial resistance, C. difficile has been categorized by the Centers for Disease Control and Prevention as one of three "urgent" threats (http://www.cdc.gov/drugresistance/threat-report-2013/). Although C. difficile was first described in the late 1970s, the past decade has seen the emergence of hypertoxigenic strains that have caused increased morbidity and mortality worldwide. Pathogenic strains, host susceptibility, and other regional factors vary and may influence the clinical manifestation and approach to intervention. In this article, we describe the global epidemiology of CDI featuring the different strains in circulation outside of North America and Europe where strain NAP1/027/BI/III had originally gained prominence. The elderly population in health care settings has been disproportionately affected, but emergence of CDI in children and healthy young adults in community settings has, likewise, been reported. New approaches in management, including fecal microbiota transplantation, are discussed.

Risks factors and outcomes of Clostridium difficile infection in patients with cancer: a matched case-control study

PURPOSE

Clostridium difficile infection (CDI) is the leading cause of diarrhoea in hospitalised patients. Cancer populations are at high-risk for infection, but comprehensive evaluation in the current era of cancer care has not been performed. The objective of this study was to describe characteristics, risk factors, and outcomes of CDI in cancer patients.

METHODS

Fifty consecutive patients with CDI at a large Australian cancer centre (2013-2015) were identified from the hospital pathology database. Each case was matched by ward and hospital admission date to three controls without toxigenic CDI. Treatment and outcomes of infection were evaluated and potential risk factors were analysed using conditional logistic regression.

RESULTS

Patients with CDI had a mean age of 59.7 years and 74% had an underlying solid tumour. Healthcare-associated infection comprised 80% of cases. Recurrence occurred in 10, and 12% of cases were admitted to ICU within 30 days. Severe or severe-complicated infection was observed in 32%. Independent risk factors for infection included chemotherapy (odds ratio (OR) 3.82, 95% CI 1.67-8.75; p = 0.002), gastro-intestinal/abdominal surgery (OR 4.64, 95% CI 1.20-17.91; p = 0.03), proton pump inhibitor (PPI) therapy (OR 2.47, 95% CI 1.05-5.80; p = 0.04), and days of antibiotic therapy (OR 1.04, 95% CI 1.01-1.08; p = 0.02).

CONCLUSIONS

Severe or complicated infections are frequent in patients with cancer who develop CDI. Receipt of chemotherapy, gastro-intestinal/abdominal surgery, PPI therapy, and antibiotic exposure contribute to infection risk. More effective CDI therapy for cancer patients is required and dedicated antibiotic stewardship programs in high-risk cancer populations are needed to ameliorate infection risk.

The epidemiology of Clostridium difficile infection in patients with cancer

INTRODUCTION

Clostridium difficile infection (CDI) is a significant cause of healthcare-associated diarrhoea, and the emergence of endemic strains resulting in poorer outcomes is recognised worldwide. Patients with cancer are a specific high-risk group for development of infection. Areas covered: In this review, modifiable and non-modifiable risk factors for CDI in adult patients with haematological malignancy or solid tumours are evaluated. In particular, the contribution of antimicrobial exposure, hospitalisation and gastric acid suppression to risk of CDI are discussed. Recent advances in CDI treatment are outlined, namely faecal microbiota transplantation and fidaxomicin therapy for severe/refractory infection in cancer populations. Outcomes of CDI, including mortality are presented, together with the need for valid severity rating tools customised for cancer populations. Expert commentary: Future areas for research include the prognostic value of C. difficile colonisation in cancer patients and the potential impact of dedicated antimicrobial stewardship programs in reducing the burden of CDI in cancer units.

Epidemiology of Clostridium difficile infections in Australia: enhanced surveillance to evaluate time trends and severity of illness in Victoria, 2010-2014

BACKGROUND

With epidemic strains of Clostridium difficile posing a substantial healthcare burden internationally, there is a need for longitudinal evaluation of Clostridium difficile infection (CDI) events in Australia.

AIM

To evaluate time trends and severity of illness for CDI events in Australian healthcare facilities.

METHODS

All CDI events in patients admitted to Victorian public hospitals between 1(st) October 2010 and 31(st) December 2014 were reported to the Victorian Healthcare Associated Infection Surveillance System. CDI was defined as the isolation of a toxin-producing C. difficile organism in a diarrhoeal specimen, and classified as community-associated (CA-CDI) or healthcare-associated (HA-CDI). Severe disease was defined as admission to an intensive care unit, requirement for surgery and/or death due to infection. Time trends were examined using a mixed-effects Poisson regression model, and the Walter and Edward test of seasonality was applied to evaluate potential cyclical patterns.

FINDINGS

In total, 6736 CDI events were reported across 89 healthcare facilities. Of these, 4826 (71.6%) were HA-CDI, corresponding to a rate of 2.49/10,000 occupied bed days (OBDs). The incidence of HA-CDI was highest in the fifth quarter of surveillance (3.6/10,000 OBDs), followed by a reduction. Severe disease was reported in 1.66% of events, with the proportion being significantly higher for CA-CDI compared with HA-CDI (2.21 vs 1.45%, P = 0.03). The highest and lowest incidence of HA-CDI occurred in March and October, respectively.

CONCLUSIONS

A low incidence of HA-CDI was reported in Victoria compared with US/European surveillance reports. Seasonality was evident, together with diminishing HA-CDI rates in 2012-2014. Severe infections were more common in CA-CDI, supporting future enhanced surveillance in community settings.

Bacteriophage Combinations Significantly Reduce Clostridium difficile Growth In Vitro and Proliferation In Vivo

The microbiome dysbiosis caused by antibiotic treatment has been associated with both susceptibility to and relapse of Clostridium difficile infection (CDI). Bacteriophage (phage) therapy offers target specificity and dose amplification in situ, but few studies have focused on its use in CDI treatment. This mainly reflects the lack of strictly virulent phages that target this pathogen. While it is widely accepted that temperate phages are unsuitable for therapeutic purposes due to their transduction potential, analysis of seven C. difficile phages confirmed that this impact could be curtailed by the application of multiple phage types. Here, host range analysis of six myoviruses and one siphovirus was conducted on 80 strains representing 21 major epidemic and clinically severe ribotypes. The phages had complementary coverage, lysing 18 and 62 of the ribotypes and strains tested, respectively. Single-phage treatments of ribotype 076, 014/020, and 027 strains showed an initial reduction in the bacterial load followed by the emergence of phage-resistant colonies. However, these colonies remained susceptible to infection with an unrelated phage. In contrast, specific phage combinations caused the complete lysis of C. difficile in vitro and prevented the appearance of resistant/lysogenic clones. Using a hamster model, the oral delivery of optimized phage combinations resulted in reduced C. difficile colonization at 36 h postinfection. Interestingly, free phages were recovered from the bowel at this time. In a challenge model of the disease, phage treatment delayed the onset of symptoms by 33 h compared to the time of onset of symptoms in untreated animals. These data demonstrate the therapeutic potential of phage combinations to treat CDI.

Severity and frequency of community-onset Clostridium difficile infection on an Australian tertiary referral hospital campus

BACKGROUND

Clostridium difficile infection (CDI) is increasingly being found in populations without traditional risk factors. We compared the relative frequency, risk factors, severity, and outcomes of community-onset CDI with hospital-acquired infection.

METHODS

This was a retrospective, observational study of CDI at a tertiary hospital campus in Sydney, Australia. Patients aged 15 years and older with a first episode of CDI from January 1 to December 31, 2011 were included. CDI was defined as the presence of diarrhoea with a positive enzyme immunoassay in conjunction with a positive cell cytotoxicity assay, toxin culture, or organism culture. Main outcome measures were onset of infection (hospital or community), risk factors, markers of severity, and outcomes for the two groups.

RESULTS

One hundred and twenty-nine cases of CDI infection were identified, of which 38 (29%) were community-onset. The community-onset infection group were less likely to have a recent history of antibiotic use (66% vs. 98%; p<0.001) or proton pump inhibitor use (38% vs. 69%; p=0.03) than the hospital-acquired infection group. Markers of severity and outcomes were similar in the two groups, with an overall mortality of 9%.

CONCLUSIONS

Community-onset CDI accounts for a large proportion of C. difficile infections and has a similar potential for severe disease as hospital-acquired infection. Using a history of previous antibiotic use, proton pump inhibitor use, or recent hospitalization to predict cases is unreliable. We recommend that patients with diarrhoea being investigated in emergency departments and community practice are tested for Clostridium difficile infection.

Epidemiology of Clostridium difficile infection in two tertiary-care hospitals in Perth, Western Australia: a cross-sectional study

The epidemiology of Clostridium difficile infection (CDI) has changed over time and between countries. It is therefore essential to monitor the characteristics of patients at risk of infection and the circulating strains to recognize local and global trends, and improve patient management. From December 2011 to May 2012 we conducted a prospective, observational epidemiological study of patients with laboratory-confirmed CDI at two tertiary teaching hospitals in Perth, Western Australia to determine CDI incidence and risk factors in an Australian setting. The incidence of CDI varied from 5.2 to 8.1 cases/10 000 occupied bed days (OBDs) at one hospital and from 3.9 to 16.3/10 000 OBDs at the second hospital. In total, 80 patients with laboratory-confirmed CDI met eligibility criteria and consented to be in the study. More than half (53.8%) had hospital-onset disease, 28.8% had community-onset and healthcare facility-associated disease and 7.5% were community-associated infections according to the definitions used. Severe CDI was observed in 40.0% of these cases but the 30-day mortality rate for all cases was only 2.5%. Besides a shorter length of stay among cases of community-onset CDI, no characteristics were identified that were significantly associated with community-onset or severe CDI. From 70 isolates, 34 different ribotypes were identified. The predominant ribotypes were 014 (24.3%), 020 (5.7%), 056 (5.7%) and 070 (5.7%). Whereas this study suggests that the characteristics of CDI cases in Australia are not markedly different from those in other developed countries, the increase in CDI rate observed emphasizes the importance of surveillance.

Prevalence of Clostridium difficile colonization among healthcare workers

Background

Clostridium difficile infection (CDI) has increased to epidemic proportions in recent years. The carriage of C. difficile among healthy adults and hospital inpatients has been established. We sought to determine whether C. difficile colonization exists among healthcare workers (HCWs) in our setting.

Methods

A point prevalence study of stool colonization with C. difficile among doctors, nurses and allied health staff at a large regional teaching hospital in Geelong, Victoria. All participants completed a short questionnaire and all stool specimens were tested by Techlab® C.diff Quik Check enzyme immunoassay followed by enrichment culture.

Results

Among 128 healthcare workers, 77% were female, of mean age 43 years, and the majority were nursing staff (73%). Nineteen HCWs (15%) reported diarrhoea, and 12 (9%) had taken antibiotics in the previous six weeks. Over 40% of participants reported having contact with a patient with known or suspected CDI in the 6 weeks before the stool was collected. C. difficile was not isolated from the stool of any participants.

Conclusion

Although HCWs are at risk of asymptomatic carriage and could act as a reservoir for transmission in the hospital environment, with the use of a screening test and culture we were unable to identify C. difficile in the stool of our participants in a non-outbreak setting. This may reflect potential colonization resistance of the gut microbiota, or the success of infection prevention strategies at our institution.