New Research Demonstrates a 50% Decrease in Hospital-Onset C difficile Infections

Infection Control TodayInfection Control Today, January/February 2023, (Vol. 27, No. 1)
Volume 27
Issue 1

Any decrease in the devastation of Clostridioides difficile is welcomed, but an investigative team brought the numbers down by 50%. See what control measures they used.

Clostridioides difficile under a microscope.

Clostridioides difficile under a microscope.

(Adobe Stock)

Clostridioides difficile costs billions in financial devastation and untold emotional anguish of patients and their families. However, the numbers of cases continue to rise. What can be done?

In a recent study, “Mitigating hospital-onset Clostridioides difficile: The impact of an optimized environmental hygiene program in eight hospitals,” recently published in the Cambridge University Press, the investigators spotlighted how critical thorough and effective cleaning is on the spread of C difficile, which profoundly difficult to kill. To get an in-depth look at the findings, 2 of the authors answered questions from Infection Control Today® (ICT®). Philip C. Carling, MD, is the director of infectious diseases and hospital epidemiology at Carney Hospital in the Dorchester area of Boston, Massachusetts; and Russell N. Olmsted, MPH, CIC, serves as the director of infection prevention management for Trinity Health's Integrated Clinical Services headquartered in Livonia, Michigan.

ICT®: Tell us about the recent study you conducted on mitigating hospital-onset Clostridioides difficile: what did you set out to measure and what were the study findings?

Philip Carling, MD

Philip Carling, MD

Philip C. Carling, MD and Russell N. Olmsted, MPH, CIC, FAPIC: C difficile infections are estimated at half a million per year, causing 29,000 deaths, especially among at-risk individuals,and costing more than $5.4 billion in excess health care costs. Despite many efforts across the industry, the past 30 years of C difficile mitigation efforts have proven ineffective in substantially reducing hospital-onset C difficile infections (HO-CDI). We set out to dig deeper on the issue—given the lack of evident solutions.

As infection preventionists know, C difficile bacteria spores are extremely difficult to kill. You must use a sporicide to kill them. However, daily sporicidal use among hospitals—every room, every day—remains low. The primary reason is that many sporicides are too hard on hospital equipment and devices. That changed in 2015 when a highly effective and environmentally-safe daily sporicide came on the market.

Our study was supported by previous research fromShaughnessy MK et al and Kundrapu et al that identified that admission to a room that was previously used to care for a patient with C difficile increased risk to subsequent occupants.1,2 This “room placement” risk factor has also been confirmed by Root ED and most recently by Sood G. These studies shed a light on the role asymptomatic carriers play in transmitting HO-CDI.3,4 Given that residual C difficile spores can be asymptomatically shed onto surfaces by the preceding room occupant, it makes a strong argument for hospital-wide daily sporicidal cleaning that mitigates risk for placement in any inpatient room that is available.

The objective of our study was to put a spotlight on the critical role of thorough and effective cleaning in decreasing HO-CDI. Specifically, we were looking to objectively quantify the impact of combining daily, hospital-wide sporicidal use with robust training, an evidence-based process, and actionable cleaning data.

The findings were unprecedented. We achieved a sustained 50% decrease in HO-CDI compared to control hospitals. We found that an optimized cleaning process, environmental hygiene monitoring and feedback to environmental services (EVS) staff to optimize cleaning thoroughness was effective in sustainably reducing infection rates. Given our results, it is very likely that implementing such a programmatic intervention could have a significant impact on the way hospitals address HO-CDI mitigation moving forward.

Russell N. Olmsted, MPH, CIC, FAPIC

Russell N. Olmsted, MPH, CIC, FAPIC

ICT®: What methods were used for conducting the study, and how did these methods impact the outcomes?

PCC and RNO: The study was conducted across 8 hospitals with stable endemic HO-CDI. Following an 18-month preintervention control period, each site implemented a daily hospital-wide sporicidal disinfectant patient zone cleaning, followed by cleaning thoroughness performance feedback using a previously validated process improvement program.

We incorporated the daily use of a sporicide (in every room, every day) that provided effective disinfection and is compatible with a wide range of environmental surfaces. This is important because other historical sporicidal disinfectants like dilute sodium hypochlorite can’t be used daily because they are too harsh on surfaces and finishes.

This study was the first to monitor the daily, hospital-wide use of a sporicide to evaluate the impact on endemic C difficile transmission. Rigorous controls were built into the study design. Many studies over the years have tried to evaluate interventions to mitigate transmission risks for C difficile. However, these are multi-factorial, making determination of the relative contribution of specific interventions more challenging. This was the first-ever controlled study of a single type of intervention—in this case, optimized environmental hygiene—to decrease endemic transmission of C difficile.

ICT®: What made the biggest impact in driving the significant reduction in C difficile?

PCC and RNO: The study puts a strong emphasis on standardization of policies and procedures for daily and discharge cleaning and disinfection of health care facilities by EVS technicians with proper training and support. These policies and procedures were based on the Association for the Health Care Environment’s (AHE) Practice Guidance for Health Care Environmental Cleaning.5

It also revealed the critical role of both the daily use of a sporicide, as well as monitoring and feedback to EVS personnel on how well they are cleaning inpatient rooms and other spaces using a fluorescent marking system that is targeted on frequently touched patient-zone surfaces. Alone, neither one of these interventions would have been able to mitigate HO-CDI to the extent the study found when these interventions were combined.

ICT®: Are the findings of this study more or less significant compared to similar studies?

PCC and RNO: This investigation builds on prior studies that demonstrate the critical role environmental surfaces play in cross transmission of C difficile in health care settings. The findings are significant in demonstrating efficacy of an EVS program that highlights the importance of the daily work of EVS personnel to provide a safe, clean environment for patients, other health care personnel and visitors. It also is significant in that it demonstrates efficacy of a sporicidal disinfectant for disinfection of all inpatient rooms, not just those that housed a patient with known acute C difficile infection.

ICT®: What are some of the key takeaways for hospitals based on the findings?

PCC and RNO: The objectively quantified results tell us 2 things. First, they highlight the significant role asymptomatic carriers play in the spread of C difficile and the impact daily cleaning can have on controlling environmental contamination from this group. Second, the results underscore the dramatic impact optimized environmental hygiene and the work of EVS professionals can have on reducing transmission. It’s not enough to use a daily sporicide hospital-wide—without also assuring that the cleaning is thorough and consistent. That’s why training and cleaning feedback is so important.

ICT®: What significance will this research have in the future mitigation of C difficile transmission?

PCC and RNO: Until now, there has not been a study conducted to this level of rigor, nor that has taken into account newer research on the understanding of the epidemiology of C difficile transmission. As discussed in a recent review, this intervention to mitigate HO-CDI is clear cut, and the results are strong enough that hospitals with ongoing endemic HO-CDI cases should consider the relevance of the study to their own institutions.6


  1. Shaughnessy MK, et al. Evaluation of hospital room assignment and acquisition of Clostridium difficile infection.Infect Control Hosp Epidemiol. 2011; 32: 201-206.
  2. Kundrapu S, et al. Skin and environmental contamination in patients diagnosed with Clostridium difficile infection but not meeting clinical criteria for testing. Infect Control Hosp Epidemiol. 2015 Nov;36(11):1348-50.
  3. Root ED, et al. Investigating the association of room features with health care-facility-onset Clostridioides difficile: An exploratory study. Infect Control Hosp Epidemiol. 2021 Jul;42(7):847-852.
  4. Sood G, et al.Clostridioides difficile infection (CDI) in a previous room occupant predicts CDI in subsequent room occupants across different hospital settings. Am J Infect Control 2022 Feb 23;S0196-6553(22)00079-7.
  5. AHE. Practice Guidance for Health Care Environmental Cleaning, The Essential Resource for Environmental Cleaning and Disinfection. Available at: Practice Guidance for Health Care Environmental Cleaning, 3rd Edition eBook | AHE 2022, Chicago, IL: A
  6. Carling, PC. Health care environmental hygiene: New insights and Centers for Disease Control and Prevention guidance. Infect Dis Clin North Am 2021;35:609–629.

Author bios:

Philip C. Carling, MD, is the director of infectious diseases and hospital epidemiology at Carney Hospital in the Dorchester area of Boston, Massachusetts. He teaches and is involved in clinical research at Boston University School of Medicine where he is a professor of clinical medicine. Carling’s research activities have primarily related to developing processes to evaluate and improve patient area surface disinfection cleaning and translational research related to the role of wastewater drains in hospital acquired infections.

Russell N. Olmsted, MPH, CIC, serves as the director of infection prevention management for Trinity Health's Integrated Clinical Services headquartered in Livonia, Michigan. He has over 39 years of experience in the fields of infection prevention and control and health care epidemiology.

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