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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
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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.
