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2. . . . CDAD. AAD antibiotic-associated diarrhea. . hospital-acquired diarrhea. . Antibiotic Associated Diarrhea?. Most causes unknown. Several candidates studiedClostridium difficile is the major recognized cause Candida speciesClostridium perfringensStaphylococcus aureusSerendipitous inf
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1. Clostridium Difficile Associated Diseases ???, M.D. PhD
Division of Infectious Diseases
Infection Prevention and Control Team
The First Hospital of China Medical University
May 2010
3. Antibiotic Associated Diarrhea? Most causes unknown.
Several candidates studied
Clostridium difficile is the major recognized cause
Candida species
Clostridium perfringens
Staphylococcus aureus
Serendipitous infection by viruses, Salmonella, etc.
Non-infectious changes in colonic fatty acid and carbohydrate metabolism induced by antibiotics
4. C difficile-causative agent in:
10-25 % of patients with AAD
50-75 % of patients with antibiotic-associated colitis (AAC)
90-100 % of patients with PMC
Aslam et al, Lancet Inf. Dis, 2005
5. Confusing terminology Antibiotic-associated diarrhea(AAD)
C. difficile is only one cause
Clostridium difficile-associated diarrhea(CDAD)
diarrhea + positive stool test
Clostridium difficile colitis(CDC)
underlying pathologic process
Pseudomembranous colitis(PMC)
endoscopic demonstration of exudative lesions
Toxic megacolon
radiologic and surgical diagnosis
6. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
7. History 1893-first case of PMC
-reported as diphtheritic colitis.
1935-“Bacillus difficile” first isolated
-Hall & O’Toole
1970s-antibiotic-asociated colitis identified.
1977 - Birmingham General Hospital-C. difficile identified as cause
1978-C. difficile toxins identified in humans.
1979-therapy with metronidazole or
vancomycin
2000-increased incidence and virulence
8. Why are we concerned? Increasing numbers of infections.
Potential for severe disease
Emergence of hypervirulent strains that may be more transmissible and/or cause more severe disease e.g. ribotype O27.
Concerns over possible antibiotic resistance.
Increasingly recognized as a major nosocomial pathogen capable of causing outbreaks
9. Increase in cases More than 50,000 cases reported in England in 2007
Fifty-fold increase since 1990; 20% of cases <65
10. National Estimates of US Short-Stay Hospital Discharges with C. difficile as First-Listed or Any Diagnosis
11. C.difficile deaths CDAD cited on 1 in every 250 death certificates in 2005
Further 72% increase in 2006
12. CDAD Rates and Mortality Increasein Parallel with Patient Age
13. Acute care hospitals with CDADoutbreaks between 2001 and 2004
14. Public concern
15. Official reports
16. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
17. CDAD Transmission:
Carried in GIT of 3% of general population
Up to 30% of hospitalized patients become colonized
Fecal-Oral Route
-sensitive individuals can become infected if they touch items or surfaces that are contaminated with feces and then touch their mouth or mucous membranes.
Hands of hospital personnel are important intermediary
-can spread the bacteria to other patients or contaminate surfaces with contact.
18. Exotoxin A (enterotoxin) :
MOA unknown/causes outpouring of fluid and a watery diarrhea
Exotoxin B (cytotoxin):
damages colonic mucosa leading to pseudomembrane formation
mechanism is via ADP-ribosylation of Rho (a GTP-BP)
this causes depolymerization of actin in the cytoskeleton Pathogenicity of C. difficile
19. Normal bacterial flora
-prevent establishment of C. difficile
colonization of the GI tract
Antibodies (serum and mucosal?)
-prevent CDAD disease if colonization
occurs
-Antibodies are probably first acquired in
infancy
Host Protection AgainstCDAD Occurs at Two Levels
20. Risk Factors Age >65 years
Severe underlying disease
Antimicrobial therapy
Clindamycin, 3rd G cephalosporins, penicillin, FQs
Nasogastric intubation
Anti-ulcer medications
Proton pump inhibitors
Chemotherapy
Long hospital stay or long-term care residency
21. Role of Antibiotics in CDAD Any antibiotic may be associated with CDAD.
Disruption of normal intestinal flora
-the determining antibiotic event
susceptibility window: following an antibiotic there is a variable-length window during which a patient is susceptible.
C. difficile resistance to the precipitating
antibiotic is thought to be important, but is not
always present (e.g. ampicillin).
22. Time-Course of Antimicrobial Effect onthe Normal Gut Flora and CDAD Risk 1. C. difficile resistance to the antibiotic used enables the organism to infect while the antibiotic is being given.
2. Resistant and Susceptible C. difficile can infect after the antibiotic has been stopped and the flora remains disrupted.
23. Original (Incorrect) Hypothesis for C. difficile Hospital Infection
24. Rate of CDAD in Patients Colonized and Non-colonized with CD Data from four prospective studies in which rectal swab cultures were obtained weekly from hospitalized patients
25. Revised Hypothesis for CDAD
26. Pathogenesis of CDAD
28. TcdC Variants
29. Epidemic strains from Quebec/UK/US-carry binary toxin/have tcdC deletion/toxinotype III tested in vitro for toxin A and B,(compared with non-epidemic toxinotype 0 strains).
Epidemic C. difficile Strains ProduceIncreased Toxins A and B in vitro
30. Epidemic C. difficile Strains ProduceIncreased Toxins A and B in vitro
31. States with the epidemic strain of C. difficile confirmed by CDC 11/15/2005 (N=16)
32. States with the Epidemic Strain of C. difficile Confirmed by CDC and Hines VA labs (N=23),Updated 2/9/2007
33. Outbreak Strains are NOT New: Comparisonof Historic and Epidemic REA “BI” types Historic BI (Bee-Eye) isolates were found from 1983 to 1992, were of BI types BI1 to BI5, contained binary toxin genes, and the 18 bp deletion in the tcdC gene.
Historic isolates were NOT resistant to newer fluoroquinolone antibiotics.
New epidemic BI isolates (types BI6-BI19) are uniformly resistant to the newer FQs (gatifloxacin, moxifloxacin).
34. Is Increased Toxin A and B in vitro the Answer to Increased Pathogenicity?
35. What is the Role ofFluoroquinolone Resistance? Resistance to newer fluoroquinolones
(gatifloxacin and moxifloxacin) is the only
detectable difference between historic nonepidemic BI group isolates and epidemic current BI group isolates.
Fluoroquinolone use has been a risk factor for CDAD in hospitals with outbreaks caused by the epidemic strain of C. difficile.
36. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
37. Clinical Presentation Asymptomatic colonization
Mild disease
Non-bloody diarrhea
Mild abdominal tenderness
Severe disease
Pseudomembranous colitis
Paralytic ileus
Ileitis
Toxic megacolon
Ulcerative colitis
Perforation(peritonitis)
Ascites
38. Clinical presentation: Epidemic Similar to old cases but more severe
More toxic megacolon (less diarrhea)
Profound leukemoid reactions
Severe hypoalbuminemia (PLE)
Septic shock
Need for colectomy
Increased mortality
40. -Other causes of toxic megacolon are UC, Crohn’s, ischemic colitis, amebiasis, bacterial dysentery, pseudomembranous colitis
-cecal perforation is imminent when the transverse diameter reaches 9 cm (normal diameter of cecum is 5 cm, of transverse colon is 4 cm, of descending colon is 3 cm)-Other causes of toxic megacolon are UC, Crohn’s, ischemic colitis, amebiasis, bacterial dysentery, pseudomembranous colitis
-cecal perforation is imminent when the transverse diameter reaches 9 cm (normal diameter of cecum is 5 cm, of transverse colon is 4 cm, of descending colon is 3 cm)
41. Leukocytosis and CDAD – Do Not Missthis Clue to Possible Fulminant Disease Toxin A is a potent neutrophil chemoattractant
CDAD found
in 16% of patients with WBC>15,000/mm3
25% of patients with WBC>30,000/mm3.
Clin Infect Dis 2002;34:1585-92
58% of 60 patients with unexplained WBC >15,000/mm3 had CD toxin in stool.
AJM 2003;115:543-6
42. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
43. Diagnosis of CDAD S/S
Endoscopy (pseudomembranous colitis)
Culture
Cell culture cytotoxin test
EIA toxin test
PCR toxin gene detection
45. Pseudomembranous Colitis
46. Laboratory diagnosis Culture
Easy and sensitive but slow
High carriage rates in hospitalised patients
Non-toxigenic isolates detected as well
Not used for initial diagnosis now
Toxin detection in faeces
Cell culture
“Gold standard” but relatively slow
Enzyme immunoassays(EIA)
Rapid/cheap/specific
Need test to include Toxin A and B
Variable sensitivity
Asymptomatic carriage issue
Single negative result does not exclude infection
Regardless of method you must take clinical picture into account!
47. Performance characteristics of diagnostic tests
48. CDAD Case Definition Stool characteristic
Diarrhea (most common)
No diarrhea
Associated with toxic megacolon or ileitis
Documented by radiology
= 1 of the following
Stool positive for:
C. difficile toxin
C. difficile determined to be a toxin producer
Pseudomembranous colitis by:
Endoscopy
Histological exam
49. CDAD vs Antibiotic-Associated Diarrhea
50. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
51. Treatment of CDAD - General principles
Whenever possible withdraw the offending antibiotic
Use oral antimicrobials whenever possible
Be patient
-some improvement seen in first 2 days but mean time until resolution of diarrhea is 2-4 days. Don’t call them nonresponders until 6 days of therapy
Treat for 10-14 days
Avoid antiperistaltic agents
52. Muto CA, et al. Infect Control Hosp Epidemiol 2005;26:273-280 Rate of antibiotic resistance in 91 C. difficile isolates from a Pittsburg hospital that experienced a large CDAD outbreak beginning January 2000
54. Vancomycin Enemas Non-randomized open trial
-6/8 patients with ileus responded in 4-17 days
-2 patients died, one following colectomy
Inf Cont Hosp Epidemiol 1994;15:371-381
Adjunct treatment for severe C. difficile Entry criteria not clearly defined
-8/9 cases resolved
Apisarnthanarak et al Clin Inf Dis 2002;35:690-96
55. Patient Management
56. Relapsed Disease Due to spores that germinate in gut after withdrawal of the antibiotic
Happens in 20+ % of patients who initially respond. Increased risk in
Age > 65
Increased severity of underlying disease
Exposure to additional antibiotics after treatment
Low serum IgG response to toxin A
Half of relapses are actually re-infections
Antibiotic resistance unlikely
Most patients will respond to a second course of the same antimicrobial
57. Treatment of Multiple Relapses No controlled studies, lots of anecdotes and “personal favorite” regimens
-tapering courses of vancomycin or metronidazole
-vancomycin plus rifampin
-yogurt or other Lactobacillus preparations
-Saccharomyces boulardii plus antibiotics
-Intravenous immune globulin
-Cholestyramine with or without antimicrobials
59. Fecal bacteriotherapy effective: 94-100% success in limited published investigations
reduces the risk of resistant bacteria or drug allergy
safe: No published adverse effects
Low-tech therapy that can be administered easily
inexpensive
60. Treatment Controversies Is metronidazole still effective therapy for CDAD?
Have clinically important metronidazole-resistant C. difficile strains been detected?
The good news is that new treatment drugs are in clinical trials for the first time in 25 years.
61. Retrospective Reports of Poor CDADResponses to Metronidazole Reduced response rates and higher recurrence rates with metronidazole in 207 CDAD patients compared to prospective published studies.
Musher DM et al, CID 2005;40:1586-90
Reduced response rates and higher recurrence rates with metronidazole in 438 Quebec patients treated in 2003-2004 than in 688 patients treated from 1991-2002: Epidemic strain identified in Quebec since 2003.
Pepin J et al, CID 2005;40:1591-7
62. Metronidazole Treatment Failure wasNot Caused by Metronidazole(MTR)Resistance in One Study 10-year prospective surveillance: 14/632 (2%)
episodes of CDAD did not respond to treatment with MTR
Susceptibility of 10 isolates from MTR treatment failures compared to 20 isolates from MTR treatment successes:
63. Treatment of First Recurrence of CDAD with MTD 33% of patients with 1st recurrence had a 2nd
Recurrence rate correlates with age and LOS
64% second recurrences occurred within 30 days and the remainder between 31-60 days.
Metronidazole was not inferior to vancomycin for treatment of first recurrence of CDAD
Treatment of first recurrence with the same or a different agent made no difference in outcome
Complications (shock, colectomy, perforation, megacolon, death) developed in 11% with first recurrence, a higher rate than previously observed
64. Investigational Rx for CDAD
65. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
66. CDAD prevention and control Antimicrobial stewardship
-protocols/consumptionsurveillance/Audit and feedback
Surveillance
-active surveillance
Education
-staff and visitors
Early diagnosis
-timely stool specimens/toxin testing/
67. CDAD prevention and control Isolation precautions
-single rooms or cohorts / designated staff
-hand washing facilities/en-suite toilet
-dedicated care equipment/door kept closed
Hand hygiene-handwashing or alcohol?
Personal protective equipment (PPE)
Environmental cleaning
Use of care equipment
68. CDAD prevention and control Hand hygiene
Personal protective equipment (PPE)
Environmental cleaning
Use of care equipment
69. CDAD prevention and control Hand hygiene
Personal protective equipment (PPE)
Environmental cleaning
Use of care equipment
70. CDAD prevention and control Hand hygiene
Personal protective equipment (PPE)
Environmental cleaning
Use of care equipment
71. CDAD prevention and control Hand hygiene
Personal protective equipment (PPE)
Environmental cleaning
Use of care equipment
72. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
73. Community Associated CDAD(CA-CDAD) and Peripartum CDAD Voluntary reporting of 23 CA-CDAD and 10 peripartum CDAD cases from 4 states over 28 months.
CA-CDAD rate in Philadelphia was calculated to be a minimum of 7.6 per 100,000 population (no higher than previous community reports).
24% of the patients reported no antibiotic use in the previous 3 months (highly unusual, but not verified).
4 patients (12%) had exposure to another CDAD case.
Only 2 isolates were recovered: each had the binary toxin gene and one had the tcdC gene deletion, but neither was toxinotype III (the new “epidemic strain”).
74. CA-CDAD and Gastric Acid Suppression Community UK GP data base (1994-2004) searched for pts with CA-CDAD and use of gastric acid suppressives
CA-CDAD rate increased from 1/100K to 22/100K.
PPIs 23% CA-CDAD cases
8% controls (Adj Rate Ratio 2.9 (95% CI 2.4-3.4).
H2 antagonists 8% CA-CDAD cases
4% controls (Adj RR 2.0 (95% CI 1.6-2.7).
NSAIDS 38% CA-CDAD cases
24% controls (Adj RR 1.3 (95% CI 1.2-1.5).
Antibiotics 37% CA-CDAD cases
13% controls (Adj RR 3.9 (95% CI 2.7-3.6).
75. Stomach Acid-Suppressing Medications and Community-Acquired CDAD, England
76. Are PPIs a Risk for CDAD in Canada? In 1187, 591 (50%) received abx and PPIs
-CDAD rate of 9.3% [RR=2.1(95% CI 1.4-3.4)].
596 received only abx
-CDAD rate of 4.4% CMAJ 2004;171:33-38
Case control study of 94 CDAD patients, PPI use
had an Adjusted Odds Ratio=2.6 (95% CI 1.3-5.0)
CMAJ 2004;171:33-38
In 7421 admissions, 293 CDAD cases occurred, and
PPI use had an Adjusted Hazard Ratio=1.0 (CI 0.8-1.3)
CID 2005;41:1254-1260
In a case control study of 237 CDAD patients, PPI use
in 47.3% of cases and 46.8% of controls (P=0.92)
NEJM 2005;353:2442-9
77. Role of Chemotherapy Administration in CDAD True incidence remains unknown
Of 70 patiens hospitalized with diarrhea after chemotherapy ,1/3 responded to empiric metrinidazole or vancomycin
Clostridium difficile can induced in animals with metrotrexate or 5- FU administration. Vancomycin added to the drinking water of the animals was found to be protective.
78. History and Epidemiology
Pathogenesis
Clinical pictures
Diagnosis
Management
Prevention and control
Future
Summary
79. Summary CDAD-important hospital diarrhea and AAD
Emerging epidemic C. difficile isolates are associated with higher CDAD rates and increased mortality.
Candidate pathogenicity factors at present are increased toxin A and toxin B production, binary toxin, and FQs resistance, which is the only factor not found in nonepidemic, but FQs are not the only antibiotic risks.
Emerging CA-CDAD
The role of PPIs, chemotherapy as risk factors for CDAD remains elusive as well.
80. Summary Treatment of CDAD
-metronidazole and vancomycin till the maistay
-metronidazole response may be reduced or slowed and
recurrence rates increased, but retreatment is effective
-vancomycin recommended in severe cases
Prevention and control
-alcohol gels remove more C. difficile spores than
expected but are not as effective as hand washing.
81. ????
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