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Explore the bacteriology, clinical presentation, and management of Clostridium difficile as a cause of antibiotic-associated diarrhea (AAD). Learn about risk factors, laboratory approaches for diagnosis, and strategies to prevent recurrence.
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Antibiotic associated diarrhoea Dr. Muhabat Raji Images used in this lecture were obtained from various internet websites. Their use is for educational purposes only.
Expectations..... • Describe • the bacteriology and virulence characteristics of Clostridium difficile as a cause of AAD • the risk factors and clinical presentation of AAD • Discuss the principle of management and risk of recurrence in AAD • laboratory approaches to the diagnosis of AAD
Outline • Introduction • Bacteriology and virulence of C. difficile • Pathophysiology of AAD due to C. difficile • Risk factors for AAD • Laboratory approaches to the diagnosis of AAD • Principles of management and recurrence
Introduction • An anaerobic, spore-producing, gram-positive rod that was first isolated and described in 1935 • It was difficult to isolate the bacterium hence the name “difficile” • It is the most common cause of AAD or nosocomial diarrhoea
Introduction • It is implicated in • 20% to 30% of patients with antibiotic-associated diarrhea (AAD) • 50% to 75% of those with antibiotic-associated colitis(AAC) • more than 90% of those with antibiotic-associated pseudomembranous colitis (PMC) • CDI is an important hospital-acquired infection associated with an increase in length of hospital stay and cost
Introduction • Spores can persist in the environment for a long time. • Colonization rate • 20-70% of healthy infants • 3% healthy adults (2-15%) • 20% of hospitalized patients
Introduction • Pathogenic strains of C. difficile produce toxins • Toxin A (enterotoxin) • Toxin B (cytotoxin) • Binary toxin • A+/ B+ strains • A-/B+ strains
Introduction • New strain identified • B1/NAP1/027 • associated with increase toxin production • resistant to quinolones
Introduction: community acquired vs. hospital acquired discharge admission 3 months after discharge 48 hours 4 weeks 8 weeks CA HA CO-HA indeterminate CA modified from McDonald LC et al, ICHE 2007;28:140-45
Transmission www.cdc.gov/ncidod/dhqp/pdf/infDis/Cdiff_CCJM02_06.pdf
Pathophysiology: Clostridium difficile http://www.scielo.org.co/scielo.php
Clinical presentation • The following scenario may occur • asymptomatic carriage • symptomatic disease (during antibiotic treatment, a few days after/weeks after antibiotic treatment) • AAD, • AAC, • PMC, • toxic megacolon
Clinical presentation • Diarrhoea (stools are usually mucoid, greenish and foul smelling) • toxic megacolon megacolon
Clostridium difficile: Lab tests • gram positive spore forming anaerobic bacilli • toxigenic strains are pathogenic and can cause disease • positive culture does not always mean an infection • presence of toxin in stools confirms diagnosis of CDI C. difficile spores http://www.cdiff-support.co.uk/images/spores.jpg
Other investigations.. • Endoscopy • Radiological investigation
Clostridium difficile: Lab tests • Stool culture • sensitive • 2-3 days for growth • cannot distinguish between toxigenic and non toxigenic • cell cytotoxin test • specific for cytotoxin B • EIA • toxin A only • toxin A and B • NAAT • toxin gene
Management • discontinue the offending antimicrobial • IV fluid resuscitation • start on oral metronidazole or vancomycin • IV metronidazole maybe given but IV vancomycin should not be given • surgery (medical non responders, perforated colon or megacolon)
Management • Isolation/cohort nursing • barrier nursing • hand washing with soap and water • alcohol based hand sanitizers not effective against spores • room cleaning with 1:10 bleach solution • do not use anti-motility medication
Recurrence • about 20% of patients • 50% (re-infection with a new strain) • 50% (relapse) • stool transplants (NGT or enema)
Conclusion • C. difficile is responsible for most cases of antibiotic associated diarrhoea • risk factors include use of antibiotics and hospital admission • Infection control procedures particularly hand washing with soap and water is very important to prevent spread of organism in a HC facility.
