Clostridium difficile in England: can we stop washing our hands?

Inpatient fluoroquinolone use in Veterans' Affairs hospitals is a predictor of Clostridioides difficile infection due to fluoroquinolone-resistant ribotype 027 strains

BACKGROUND

Reduction in the use of fluoroquinolone antibiotics has been associated with reductions in Clostridioides difficile infections (CDIs) due to fluoroquinolone-resistant strains.

OBJECTIVE

To determine whether facility-level fluoroquinolone use predicts healthcare facility-associated (HCFA) CDI due to fluoroquinolone-resistant 027 strains.

METHODS

Using a nationwide cohort of hospitalized patients in the Veterans' Affairs Healthcare System, we identified hospitals that categorized >80% of CDI cases as positive or negative for the 027 strain for at least one-quarter of fiscal years 2011-2018. Within these facilities, we used visual summaries and multilevel logistic regression models to assess the association between facility-level fluoroquinolone use and rates of HCFA-CDI due to 027 strains, controlling for time and facility complexity level, and adjusting for correlated outcomes within facilities.

RESULTS

Between 2011 and 2018, 55 hospitals met criteria for reporting 027 results, including a total of 5,091 HCFA-CDI cases, with 1,017 infections (20.0%) due to 027 strains. Across these facilities, the use of fluoroquinolones decreased by 52% from 2011 to 2018, with concurrent reductions in the overall HCFA-CDI rate and the proportion of HCFA-CDI cases due to the 027 strain of 13% and 55%, respectively. A multilevel logistic model demonstrated a significant effect of facility-level fluoroquinolone use on the proportion of infections in the facility due to the 027 strain, most noticeably in low-complexity facilities.

CONCLUSIONS

Our findings provide support for interventions to reduce use of fluroquinolones as a control measure for CDI, particularly in settings where fluoroquinolone use is high and fluoroquinolone-resistant strains are common causes of infection.

Seasonality and community interventions in a mathematical model of Clostridium difficile transmission

BACKGROUND

Clostridium difficile infection (CDI) is the leading cause of antibiotic-associated diarrhoea with peak incidence in late winter or early autumn. Although CDI is commonly associated with hospitals, community transmission is important.

AIM

To explore potential drivers of CDI seasonality and the effect of community-based interventions to reduce transmission.

METHODS

A mechanistic compartmental model of C. difficile transmission in a hospital and surrounding community was used to determine the effect of reducing transmission or antibiotic prescriptions in these settings. The model was extended to allow for seasonal antibiotic prescriptions and seasonal transmission.

FINDINGS

Modelling antibiotic seasonality reproduced the seasonality of CDI, including approximate magnitude (13.9-15.1% above annual mean) and timing of peaks (0.7-1.0 months after peak antibiotics). Halving seasonal excess prescriptions reduced the incidence of CDI by 6-18%. Seasonal transmission produced larger seasonal peaks in the prevalence of community colonization (14.8-22.1% above mean) than seasonal antibiotic prescriptions (0.2-1.7% above mean). Reducing transmission from symptomatic or hospitalized patients had little effect on community-acquired CDI, but reducing transmission in the community by ≥7% or transmission from infants by ≥30% eliminated the pathogen. Reducing antibiotic prescription rates led to approximately proportional reductions in infections, but limited reductions in the prevalence of colonization.

CONCLUSION

Seasonal variation in antibiotic prescription rates can account for the observed magnitude and timing of C. difficile seasonality. Even complete prevention of transmission from hospitalized patients or symptomatic patients cannot eliminate the pathogen, but interventions to reduce transmission from community residents or infants could have a large impact on both hospital- and community-acquired infections.

Multidisciplinary Approach to Clostridium difficile Infection in Adult Surgical Patients

BACKGROUND

In 2017, our hospital was identified as a high outlier for postoperative Clostridium difficile infections (CDIs) in the American College of Surgeons NSQIP semi-annual report. The Department of Surgery initiated a CDI task force with representation from Surgery, Infectious Disease, Pharmacy, and Performance Services to analyze available data, identify opportunities for improvement, and implement strategies to reduce CDIs.

STUDY DESIGN

Strategies to reduce CDIs were reviewed from the literature and the following multidisciplinary strategies were initiated: antimicrobial stewardship optimization of perioperative order sets to avoid cefoxitin and fluoroquinolone use was completed; penicillin allergy assessment and skin testing were implemented concomitantly; increased use of ultraviolet disinfectant strategies for terminal cleaning of CDI patient rooms; increased hand hygiene and personal protection equipment signage, as well as monitoring in high-risk CDI areas; improved diagnostic stewardship by an electronic best practice advisory to reduce inappropriate CDI testing; education through surgical grand rounds; and routine data feedback via NSQIP and National Healthcare Safety Network CDI reports.

RESULTS

The observed rate of CDIs decreased from 1.27% in 2016 to 0.91% in 2017. Cefoxitin and fluoroquinolone use decreased. Clostridium difficile infection testing for patients on laxatives decreased. Terminal cleaning with ultraviolet light increased. Handwashing compliance increased. Data feedback to stakeholders was established.

CONCLUSIONS

Our multidisciplinary CDI reduction program has demonstrated significant reductions in CDIs. It is effective, straightforward to implement and monitor, and can be generalized to high-outlier institutions.

Why sensitive bacteria are resistant to hospital infection control

Background: Large reductions in the incidence of antibiotic-resistant strains of Staphylococcus aureus and Clostridium difficile have been observed in response to multifaceted hospital-based interventions. Reductions in antibiotic-sensitive strains have been smaller or non-existent. It has been argued that since infection control measures, such as hand hygiene, should affect resistant and sensitive strains equally, observed changes must have largely resulted from other factors, including changes in antibiotic use. We used a mathematical model to test the validity of this reasoning. Methods: We developed a mechanistic model of resistant and sensitive strains in a hospital and its catchment area. We assumed the resistant strain had a competitive advantage in the hospital and the sensitive strain an advantage in the community. We simulated a hospital hand hygiene intervention that directly affected resistant and sensitive strains equally. The annual incidence rate ratio ( IRR) associated with the intervention was calculated for hospital- and community-acquired infections of both strains. Results: For the resistant strain, there were large reductions in hospital-acquired infections (0.1 ≤ IRR ≤ 0.6) and smaller reductions in community-acquired infections (0.2 ≤ IRR ≤  0.9). These reductions increased in line with increasing importance of nosocomial transmission of the strain. For the sensitive strain, reductions in hospital acquisitions were much smaller (0.6 ≤ IRR ≤ 0.9), while communityacquisitions could increase or decrease (0.9 ≤ IRR ≤ 1.2). The greater the importance of the community environment for the transmission of the sensitive strain, the smaller the reductions. Conclusions: Counter-intuitively, infection control interventions, including hand hygiene, can have strikingly discordant effects on resistant and sensitive strains even though they target them equally, following differences in their adaptation to hospital and community-based transmission. Observed lack of effectiveness of control measures for sensitive strains does not provide evidence that infection control interventions have been ineffective in reducing resistant strains.

Why sensitive bacteria are resistant to hospital infection control

Background: Large reductions in the incidence of antibiotic-resistant strains of Staphylococcus aureus and Clostridium difficile have been observed in response to multifaceted hospital-based interventions. Reductions in antibiotic-sensitive strains have been smaller or non-existent. It has been argued that since infection control measures, such as hand hygiene, should affect resistant and sensitive strains equally, observed changes must have largely resulted from other factors, including changes in antibiotic use. We used a mathematical model to test the validity of this reasoning.

Methods: We developed a mechanistic model of resistant and sensitive strains in a hospital and its catchment area. We assumed the resistant strain had a competitive advantage in the hospital and the sensitive strain an advantage in the community. We simulated a hospital hand hygiene intervention that directly affected resistant and sensitive strains equally. The annual incidence rate ratio ( IRR) associated with the intervention was calculated for hospital- and community-acquired infections of both strains.

Results: For the resistant strain, there were large reductions in hospital-acquired infections (0.1 ≤ IRR ≤ 0.6) and smaller reductions in community-acquired infections (0.2 ≤ IRR ≤  0.9). These reductions increased in line with increasing importance of nosocomial transmission of the strain. For the sensitive strain, reductions in hospital acquisitions were much smaller (0.6 ≤ IRR ≤ 0.9), while communityacquisitions could increase or decrease (0.9 ≤ IRR ≤ 1.2). The greater the importance of the community environment for the transmission of the sensitive strain, the smaller the reductions.

Conclusions: Counter-intuitively, infection control interventions, including hand hygiene, can have strikingly discordant effects on resistant and sensitive strains even though they target them equally, following differences in their adaptation to hospital and community-based transmission. Observed lack of effectiveness of control measures for sensitive strains does not provide evidence that infection control interventions have been ineffective in reducing resistant strains.