Preventing and Treating C.difficile

Lisa Casey, M.D. Assistant Professor, UT Southwestern Medical Center

TSGE / SGNA Annual Scientific MeetingSeptember 20. 2015

Clostridium difficile – the organism

• First described in 1935 (PCN first used 1943 by comparison)• Best known for infectious, antibiotic associated diarrhea• “pseudomembranous colitis”• Anaerobic, gram positive, not invasive• Forms heat, acid and antibiotic resistant spores

The Impact – morbidity:

• In 2011 there were an estimated 453,000 cases of c. difficile infection in the U.S.• Estimated 159,700 cases were community acquired• 293,000 were healthcare associated specifically 107,600 hospital acquired• 83,000 were first recurrence • 29,300 people died

• Dutch study with patients 2006-2009 – CDI was associated with a 2.5-fold increase in 30 day mortality

The Impact – financial burden

• CDC data compared CDI to other items we monitor – SSI, CLABSI,VAP, CAUTI• Nosocomial CDI more than quadruples the cost of hospitalizations,

increasing costs upward of $1.5 billion dollars a year in the U.S.

“Community” versus “healthcare” acquired• Healthcare associated• Community acquired • The grey area in between

Transmission:

• Transmitted fecal oral by spores• Spores are widely found in healthcare facilities and low level in the

environment and food supply• Normally colonization prevented by barrier properties of fecal

microbiome• Not everyone colonized develops infection – > infants

Pathogenesis – how it causes the damage• In susceptible persons, colonizes the large intestine and releases two

protein exotoxins that cause colitis• Toxin A - enterotoxin• Toxin B – cytotoxin, essential for the virulence

• Two very important factors impacting damage• Virulence of the infecting strain • Host immune response

Why are some infections worse than others?• Between 2003 and 2006 CDI seemed to be more frequent, severe ,

refractory to standard therapy and more likely to relapse• Meet BI/NAP1/027 – • More virulent• Increased toxin production• Thought associated with FQ use

What are the risk factors?

• Antimicrobial exposure• Acquisition of c.difficile• Advanced age >65 years old• Underlying illness• Immunosuppression• Tube feeds• ?gastric acid suppression

Clinical predictors – what to look for:

• Significant diarrhea – new onset >3 loose stools in 24 hours• Recent antibiotic exposure• Abdominal pain• Fever• Distinctive foul odor to the stool

Prevention strategies – core strategies:• Implement antibiotic stewardship• Contact precautions for duration of diarrhea• Hand hygiene in compliance with CDC / WHO• Cleaning and disinfection of equipment and environment • Laboratory-based alert system for immediate notification of positive

test results• Educate about CDI: HCP, housekeeping, administration, patients,

families

Prevention strategies – supplemental:• Extend use of contact precautions beyond duration of diarrhea (e.g.48

hours) (skin and environmental contamination w spores)• Presumptive isolation of symptomatic patients pending confirmation

of CDI• Evaluate and optimize testing for CDI

Prevention strategies – supplemental:• Implement soap and water hand hygiene before exiting a room of

patient with CDI• Implement universal glove use on units with high CDI rates• Use sodium hypochlorite (bleach) – containing agent for

environmental cleaning

Diagnosis

• In the past – Toxin A/B enzyme immunoassays - low sensitivities (70-80%) leading to low predictive value. • Poor test ordering practices. • Formed stool• Colonization

Limitations of testing - Colonization

• CDI is only responsible for 30-40% of hospital onset diarrhea.• Carrier rate among healthy adults is about 3%• C. difficile carrier rates in healthcare facilities ( hospitals, long term

care facilities) are 20-50% • May be a reservoir for environmental contamination /shedding spores

Hand hygiene: soap and water versus alcohol• Alcohol is not effective in eradicating C. difficile spores• Spores may be difficult to remove even with hand washing so

adherence to glove use and contact precautions should be emphasized to reduce transmission• Glove use – asymptomatic carriers have a role in transmission though

not clear the extent

How to clean the environment

• Bleach can kill spores. • Most other standard disinfectants do not. • Must carefully investigate new products before implementation.

Treatment options

• Metronidazole• Vancomycin• New antibiotics• Fecal microbial transplant

Metronidazole (Flagyl)

• Used since the 1970’s• bacteriostatic• Can be used oral or IV 500mg TID• More recent treatment failures – strain related• Lots of side effects – disulfiram reaction, carcinogenesis• Can be associated with CDI infection or colonization• Felt equivalent to Vanco for mild to moderate infection• inexpensive

Oral Vancomycin

• Only oral dosing 125mg four times daily• bacteriostatic• Not absorbed systemically and reaches high levels in colon• Cost improving with generic formulations• Safer in pregnancy and breast feeding• Believed better in moderate to severe disease, recurrence, taper

Newer antibiotic options - fidaximicin• Approved for CDI in 2011• Macrocyclic, bacteriocidal • Expensive• Believed to have a lower incidence of recurrence than vancomycin• Frequently need ID approval

Other possibilities for treatment

• Monoclonal antibodies• Against toxins A and B along with ABX• In clinical trials reduce recurrence • Not clinically available

• Vaccination• Probiotics – equivocal data • Fecal transplant

Summary prevention points:

• Prescribe antibiotics carefully• Test if more than 3 loose stools in 24 hours.• Isolate patients with CDI or suspected immediately• Wear gown and gloves and wash hands with soap and water• Clean room surfaces thoroughly with bleach• When patient transfers, notify the new facility patient has a CDI

Selected resources:

• ACG guidelines last updated February 2013 www.GI.org• Centers for Disease Control – www.CDC.gov• NEJM review article CDI April 16, 2015 – www.NEJM.org