C'difficile in BC: A snapshot perspective

1
C.difficile in BC A snapshot perspective

• Linda Hoang MSc, MD, FRCPC, DTMH
• Medical Microbiologist
• Program Head, Bacteriology Mycology Program
• BC Centre for Disease Control
• BCCDC Public Health Grand Rounds
• May 23, 2008

2
Objectives

• To briefly review the epidemiology, clinical
  presentation, diagnosis, management and
  prevention of C. difficile.
• To review the epidemic NAP 1/Ribotype 027 strain
  of C. difficile in Canada and US
• To present the preliminary results for the
  BCCDC/BCAMM/PICNet C.difficile March 2008 study
  in BC

3
C. difficile

• Anaerobic spore-forming bacillus, colonizes colon
• First identified in late 1970s as etiologic
  agent for
• 15-20 of antibiotic-related cases of diarrhea
• Pseudomembranous colitis
• Leading cause of nosocomial infectious diarrhea
• Fecal-oral transmission via contaminated
  environment and hands
• Mild, self limited disease to fulminant
  pseudomembranous colitis
• Over last decade, C.difficile associated disease
  (CDAD) a significant clinical problem in
  healthcare facilities in North America and Europe

4
Virulence factors for pathogenic strains

• Production of 2 cellular cytotoxins
• TcdA and TcdB
• Toxins regulated by tcdC and tcdD genes
• Genes part of a 19.6 kb genomic pathogenicity
  locus (PaLoc)
• 3rd toxin
• Binary toxin
• 5 clinical isolates
• Pathogenic role not clear

McDonald et al NEJM Vol 33 (23). 2005
5
Pathogenesis

• Diarrhea and colonic inflammation
• Disruption of normal colonic biota by
  antibiotics, antineoplastic agents, etc
• Colonization with toxigenic C. difficile
• Production of toxin A and/or B
• Mucosal injury and inflammation
• Toxins A and B - entertoxic and cytotoxic
• Toxin A binds carbohydrate receptors in
  intestinal epithelium
• Both induces expression of cytokines (IL-8-a
  potent chemoattractant for neutrophils), loss of
  barrier function, cell death by apoptosis
• Histologically focal epithelial ulceration
  associated with inflammatory exudate

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C. difficile toxin effects on Vero Cells
Untreated control Vero cells
1.5 hours after addition of CDTx
2 hours after addition of CDTx
5 hours after addition of CDTx
Courtesy of Dr. Martin Petric
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Clinical presentation

• After colonization
• Asymptomatic carrier
• Or develop colonic disease
• Mild to severe
• Includes fever, nausea, abdominal pain/cramping
  24 hrs after infection but up to 2-3 months
• Severe CDAD
• Independent predictors of 30-day mortality
• Leukocytosis 50 x 10 9/L
• Lactate level 5 mmol/L
• Age 75 yrs
• Immunosuppression
• Shock requiring vasopressor treatment (Ann Surg
  2007 245(2)267-72)
• Pseudomembranous colitis with little or no
  diarrhea
• Toxic megacolon and paralytic ileus
• Abdominal distention, marked leukocytosis,
  dilated and inflamed colon
• Recurrence in 15-30 of patients with CDAD
• Possible role of impaired immune response to C.
  difficile toxins (IgA)(J Clin Pathol 2004
  57(9)973-9)

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Diagnosis

• Demonstration of toxins A and/or B in stool
  samples
• Cytopathic effects on a monolayer of cells (gold
  standard)
• ELISAs for toxins A or A/B /- glutamate
  dehydrogenase
• False negative concerns
• PCR
• False positive concerns

 Sensitivity and Specificity of Tests for the
Diagnosis of C. difficile Associated Disease
Test Sensitivity () Specificity
() Utility of Test Endoscopy
51 Approximately 100 Diagnostic of PMC Culture
for C. difficile 89100 8499 Highly
sensitive isolate for further studies Cell
culture cytotoxin test 67100 85100 With
clinical data, diagnostic of CDAD EIA toxin test
6399 75100 With clinical data,
diagnostic of CDAD PCR toxin gene detection
Undetermined Undetermined Research test
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C. difficile isolates

• Toxin A/B studies
• TcdC deletion
• PFGE
• Ribotyping
• RFLP
• Restriction endonuclease
• etc

• Multiple typing methods
• Nomenclature challenge
• May be useful for outbreaks
• Standardization in Canada _at_ NML for PFGE
  designation
• E.g. NAP1/027 referred to as PFGE CDN
  designation 0001/NAP1

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Management

• Discontinue offending antibiotics
• Fluid and electrolyte replacement
• If diarrhea continues
• Oral metronidazole
• (oral vancomycin)
• For toxic megacolon or colonic perforation
• Surgery

• Recurrent disease
• Challenging!
• Antibiotics
• Lactobacillus
• Saccharomyces boulardii
• Fecal transplantation

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Prevention

• NAP1/027 has high capacity for toxin and spore
  production
• Contribute to disease severity, therapy failure,
  relapse, spread
• Akerlund et al JCM, 2008 Feb 46(4)1530-3
• Effective hospital-based prevention measures
• Aggressive infection control measures
• Prudent use of antimicrobials
• Prevention of cross-infection
• Active surveillance of cases
• What about prevention in community?
• Source not really known
• C. difficile infection may not be recognized

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Hypertoxin producing C. difficile

• First reports in 2004
• US and Canada
• Associated with increased infection rate,
  outbreaks and severe disease US, Canada, Europe
• Factors contributing to this unknown
• Hospital and community acquired
• Recent trends
• More severe disease in both traditional and
  non-traditional hosts
• Young healthy adults and children in community
• Some without antibiotic exposure

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C. difficile in Canada

• Reports of increased incidence, severity, and
  relapse of CDAD.
• Increase first described in Quebec in 2003.
• Incident rates in Quebec
• 1991 -2003 study
• Rates from 1991-2002 stable
• Incidence from 35.6 to156.3 per 100,000
• 900 per 100,000 for adults gt65 yo
• 5-fold increase in mortality, 2.5 fold increase
  in complications
• 2002-2005 14,000 cases reported in Quebec
• Quebec situation a crisis
• Costs 10-12,000 to treat each patient
• Similar trends country wide
• 67 of isolates with healthcare associated
  disease and 37 with community acquired disease
  (Lancet 2005 36694911079-84)

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C. difficile NAP1/Ribotype 027

• Genotypic markers
• North American pulsed-field type 1 (NAP 1),
• Canadian designation 0001
• Ribotype 027
• Group BI by restriction endonuclease analysis
• Toxinotype III
• Phenotypic markers
• Hyper production of toxin
• 20-fold higher toxin yield in vitro
• Resistant to fluoroquinolones and clindamycin

McDonald et al NEJM Vol 33 (23). 2005
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NAP1/027 strain toxin hyperproduction

• High concentrations of TcdA and TcdB toxins
• Early log-phase of growth
• regular strains produce toxins in lower
  concentration after stationary phase
• Deletion in the tcdC gene
• 18bp deletion ? 330-347 of tcdC gene
• 1 bp deletion ?117 tcdC
• Binary toxins
• Role unknown

JCM 2006. 44(6), 2147-2152 NEJM 2005 Vol 33 (23)
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C. difficile in Canada

• Canadian Nosocomial Infections Surveillance
  Program (CNISP)
• 1997 6 weeks, 19 hospitals, 8 provinces
• Hospitalized patients with diarrhea
• 13 caused by C. difficile
• Mean 5.9 /1000 admissions
• More frequent in gt65 and admissions gt2 weeks
• 2004/5 6 months, 34 hospitals
• Mean incidence 6.0/1000 admissions
• 27 18-bp deletion tcdC in Canada
• 60 18-bp deletion tcdC in Quebec
• 2007 4 months 44 hospitals
• Mean incidence 6.0/1000 admissions

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CNISP 2004/5 Patients with CDAD by province or
region
Mean 6.0 per 1000 admissions
Adult and adult-pediatric hospitals only, 31
hospitals
Courtesy of Dr. M. Mulvey
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C. difficile in BC

• Outbreaks in BC typing at BCCDC
• Presence of NAP1 strain since 2006
• Hospital-associated clusters
• 5.9 of C. difficile isolates from Fraser Health
  Region fall 2004, out-patient laboratory were
  ribotype 027 (JCM 2006 44(6) 2147-2152)

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Health-care-associated CDI

• C.difficile infection historically a healthcare
  associated infection
• Hospitals, LTCF, daycare facilities, outpatient
  clinics
• Definition
• Diarrhea C. difficile positive lab result
• 48-72 hr after admission
• lt72 hr and patient has history of recent exposure
  to healthcare facility (1-3 months ago)
• Burden of NAP1
• 58 Quebec hospitals (2005)
• 15 consecutive stool samples
• total 504 samples
• 95 were C. difficile pos by toxin screening
• 57 NAP1 profile

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Community-associated CDI

• Community associated cases of severe CDAD
  reported in 4 US states (MMWR 2005, 541201-1205)
  
• Patient with diarrhea, C. difficile positive lab
  assay lt72 h after admission and no history of
  recent stays at a health care facility
• 23 yr old, healthy (48 18 yo)
• 35 had no history of antibioitic exposure
• 30 thought to have acquired from other family
  members with diarrheal disease
• 26 required hospitalization
• 35 relapsed
• Other risk factors IBD, polyps, diverticultiis,
  chronic intestinal conditions

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Community-associated CDI

• Surveillance for Community-Associated Clostridium
  difficile Connecticut, 2006 (MMWR 2008,
  57(13)340-3)
• State-wide reporting x 1yr
• CA-CDAD positive C.difficile toxin assay in
  person with GI symptoms, no known overnight
  hospitalization or LTCF stays during preceding 3
  months, or within 48 hrs of hospital admission.
• 241 cases in 2006
• 46 required hospitalization
• 12 ICU care
• 2 toxic megacolon and colectomy
• 2 died

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Community-associated CDI

• 25
• No underlying conditions
• No in-patient health-exposure last 12 months
• Significantly younger lt45 yo
• Less likely to be hospitalized
• More likely to have bloody diarrhea
• 36 received no antimicrobial in prior 3 months
• (MMWR 2008, 57(13)340-3)

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Potential sources of CA-C.difficile in the
community

• Domestic animals (dogs, cats)
• Farm animals (horses, pigs, cows)
• Exposure to spores in soil,
• Carriage by pets (e.g. dogs, cats, horses) or
  other animals (e.g. pigs, cattle, mice)
• Contaminated food
• C. difficile spores identified in 20 of retail
  ground beef and veal samples, Ontario and Quebec
• tcdC 18 bp deletion present(EID 2006
  12(11)1730-6)
• Exposure to household members with diarrhea
• (MMWR Morb Mortal Wkly Rep 2005, 541201-1205)

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Risk factors
Gastroenterology Hepatology 2008, 5(1) 40-48
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Burden of C. difficile infection in BC

• Data limited
• CNISP surveillance
• 3 tertiary care centres from Vancouver Lower
  Mainland
• Identified presence of NAP1 strains in BC
  hospitals
• Publication in 2006
• Some data from out-patient lab in BC
• NAP1/027 strains present from community lab
• BCCDC
• Outbreaks from healthcare facilities in BC
• NAP1 strains present
• Burden in BC healthcare facilities?
• Burden in BC community?

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BCCDC/BCAMM/PCINet BC March 2008 study

• Objectives
• To characterize all recovered isolates of C.
  difficile in a month in BC
• To determine the relative load of NAP1/027 strain
  of C. difficile against wildtype strains in a
  month in BC
• To determine the burden of NAP1/027 strain in
  hospitals of the respective Health Authorities in
  BC
• To determine the burden of NAP1/027 strain from
  outpatient laboratories
• To compare BC rates of NAP1/027 with national
  rates by standardizing with CNISP
• To evaluate the age distribution of mutant
  strains versus the wildtype strain

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Methods

• Collaborating Laboratories in BC
• Chilliwack
• CW
• East Kootenay
• Kootenay Boundary
• Kelowna
• SPH
• Prince George
• Penticton
• Royal Columbian Hospital (Fraser Valley
  Hospitals)
• Royal Inland Hospital
• Vernon Jubilee Hospital
• VGH
• Victoria General Hospital (Vancouver Island
  Hospitals)
• Lifelabs

• Study period March 1-31, 2008
• All EIA positive stool samples
• Cultured for C. difficile, isolate sent to BCCDC
• Stool sent to BCCDC for C. difficile culture

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Methods (continued)

• Standardized methodology and supplies for
  participating laboratories in BC
• C. difficile isolation protocol
• Screen positive stool samples were plated on CDA
  plates, incubated at 35 oC for 48-72hrs
• Suspect colonies were examined by Gram stain and
  agglutination assay (Microgen Latex Agglutination
  Kit)
• Confirmed isolates were transported anaerobically
  to BCCDC
• Susceptibility testing of isolates
• BCCDC and other laboratories with capacity
  performed E-tests to
• Clindamycin, Metronidazole, Ciprofloxacin,
  Vancomycin
• Genotypic examination of isolates
• TcdC deletion
• Tox A and Tox B PCR
• PFGE
• Methods standardized against CNISP protocol

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Results (N400) Age distribution
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Distribution of mutant strains (TcdC) in BC and
Health Authority
NAP1/027
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BC March 2008Distribution of age and C.
difficile strains
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Health Authority/Private labs Mutant strains
(TcdC regulator gene)preliminary data
I case from Whitehorse 78 yo with mutant strain
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Additional preliminary data
CDN NAP
Binary Toxin
Toxin A/B
--- A/B --- A/B A/B A/B A/B A/B ---
--- neg --- pos pos pos pos pos neg

• Susceptibility testing (Clinda, Metronid, Cipro,
  Vanco) and expression studies
• Results pending

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Conclusions

• NAP1/027 C. difficile present in BC
• Hospital laboratories (0-79 of C. difficile
  recovered)
• Community laboratories (20)
• Consistent with published results
• Not yet able to determine if truly community
  associated or outpatient with exposure to risk
  factors (e.g. hospital)
• One case coincidentally identified from
  Whitehorse
• Youngest case 15 mo
• Majority elderly but also present in younger
  population
• New tcdC mutant strains identified
• ?Clinical significance?
• ?Hyper producers of toxins?

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Limitations

• One month durationreflective?
• Lack of denominator
• Total patients with diarrhea
• admitted patients in hospital/health authority
• Patient-days in hospital/health authority
• EIA screening for cases an underestimation?
• Assumed all cases are clinically significant

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BCMA guideline-on external review-

• Consider C. difficile testing
• Prolonged mild to moderate diarrhea with risk
  factors
• Prolonged mild to moderate diarrhea with
  negative routine workup
• Severe (/- bloody) diarrhea with risk factors
• Severe (/- bloody) diarrhea with negative
  routine workup

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PICNet

• Implementing a province-wide CDAD surveillance
  system to collect data on
• infection rates,
• relapse rates,
• serious complications and attributable deaths.
• System is currently being piloted in Fraser
  Health Authority
• Plan to roll out to other Health Authorities over
  the summer.

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Future Plans?

• Compare BC results with CNISP results
• Follow up on cases
• Collaboration with hospitals for chart review
• Community lab?
• Annual surveillance?
• In conjunction with PICNet CDAD Surveillance
  program?
• Evaluate severity of disease and clinical
  outcomes of community cases vs healthcare
  associated cases (PICNet project facility
  specific)?

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Future Plans?

• Hospitals
• Aggressive infection control practice to limit
  spread
• Alcohol hand wash not effective in eliminating
  spores
• Public Health
• Still many unanswered questions
• Relationship between antibiotic utilization and
  NAP1 in Health Authority?
• Environmental/animal/food sources?
• Asymptomatic carriage in population?
• General
• Clinical impact on pediatric cases?
• Host factors that promote carriage/infection?
• Enteric microbial flora
• Other unidentified risk factors?

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Acknowledgements

• Dr. Swee Han Goh
• Patricia Umlandt and Patrick Misa
• Dr. Sylvie Champagne and BCAMM members
• PICNet
• Dr. Michael Mulvey and CNISP
• Tazim Rahim, Loretta Janz, David Chan, Fern
  Shing, Tony Wong
• Technologists from all collaborating laboratories
  in BC (Chilliwack, CW, East Kootenay, Kootenay
  Boundary, Kelowna, SPH, Prince George, Penticton,
  Royal Columbian Hospital (Fraser Valley
  Hospitals), Royal Inland Hospital, Vernon Jubilee
  Hospital, VGH, Victoria General Hospital
  (Vancouver Island Hospitals), Lifelabs)