Ellen Jo Baron, Ph.D., D(ABMM) Director of Medical Affairs, Cepheid Professor Emerita, Pathology, Stanford University Minimal TAT, Maximum Impact on Infection Control for C. difficile Minimal TAT, Maximum Impact on Infection Control for C. difficile

Employee of Cepheid Consultant for: Merck, OpGen, NanoMR, MorphDesign, MicroPhage Stock holdings: Cepheid, ImmunoSciences, PolyRemedy Other renumeration: Royalties for contributions to Infectious Diseases Alert newsletter, Palo Alto VAMC, and from various IVD industry consulting companies Founder & board member of NGO: Diagnostic Microbiology Development Program ( E.J. Baron’s Conflicts of Interest

PAGE | 3 Inter-relatedness of Healthcare Associated Pathogens Which is often treated with clindamycin Which selects for Which can donate the vanA resistance gene Which may lead to Clostridium difficile VRE MRSA Which is treated with oral vancomycin VRSA (or VISA)

Sporeforming anaerobic Gr+ rod Colonizes > 50% of newborns asymptomatically; even toxigenic strains Acquisition of a new, toxigenic strain after antibiotic treatment leads to disease Spores stable in environment; not destroyed by alcohol Clostridium difficile

U.S. Numbers and Cost/yr The newest HAI >$32 million Healthcare-Associated Infections (HAI)

3 times more CDI hospitalizations in last 10 years Half of infections in patients >65 yrs but 90% of deaths 75% of infections first show in nursing home patients or those seen in clinic recently Half of patients have CDI at time of admission Based on 2008 U.S. APIC survey:  Average cost $32.1 million  Average extra hospital days = 40,200  Mortality= 14,000 patients/year Current statistics from CDC

Pharmacotherapy 2011;31(6):546–551

Rapidly increasing numbers Average 10-20% of all stools tested = Positive Wide spectrum of CDI 1 recurrence 10-25% pts Risk of 2 nd recurrence ~65%

Associated with hospital outbreaks of severe disease Associated with severe morbidity (toxic mega-colon, sepsis-like syndrome) High case-fatality rate Fluoroquinolone resistant binary toxin Produces >20x more toxin B (due to a deletion in TcdC toxin production regulatory gene) & a binary toxin Produces larger #s of spores, leading to larger inocula and easier transmission Toxinotype III Emergence of an epidemic strain BI/NAP-1/027

 Hand hygiene; gloves & gowns  Switch to soap & water from gels  Private room, contact precautions, private commode – duration of diarrhea  Remove environmental sources  Chlorine cleaning agents  Reduce non-essential antibiotics  Antibiotic stewardship program SHEA/IDSA Infect Control and Prevention Guidelines

Toxigenic culture is gold standard Cycloserine-cefoxitin-fructose agar with taurocholate Grow the organism Test isolates for toxin Plate direct or plate from broth enrichment Anaerobic incubation <1% of U.S. labs doing this test and it takes at least 4 days

Previous gold standard (2+ day TAT) Detection of Cytotoxin B direct from stool in cell culture Previous gold standard (2+ day TAT) Detection of Cytotoxin B direct from stool in cell culture Normal, negative or toxin + antitoxin = neutralized (no effect) Positive - CPE Stool supernatant <1% of U.S. labs doing this test and it takes at least 2 days

Rapid antigen detection CDI assays Enzyme immunoassays and LFAs for toxins A&B or GDH >50% of U.S. labs still using this test type !! Vidas

C. difficile Test Result Sensitivities vs Comparator EIA assays Cell culture Cytotoxin Toxigenic Culture Meridian Premier Toxins A & B EIA 92%48% Meridian Immunocard Toxins A & B 78%48-67% TechLab Toxins A & B 91%74% Remel Xpect 96%48% Wampole Tox A & B 95%55% TechLab GDH 90%88% BD GeneOhm PCR 92%89% LM Sloan et al, JCM, 2008 Jun;46(6): Eastwood et al. J. Clin. Microbiol : L Alcalá et al, JCM, 2008 Nov;46(11):

Clinical and Infection Control Implications of C. difficile Infection With Negative Enzyme Immunoassay for Toxin Guerrero et al CID 53:287-. (Cleveland VAMC) 132 PCR+ patients (unformed stools) 43 (32%) EIA negative for toxin A or B (would have been missed if only EIA used for testing or determining whom to treat) No difference in presentations: (9 pts had severe CDI and one patient died of fulminant CDI) All patients had equal shedding of spores onto body and environment (same ribotype) Of 150 strains typed, 50% were 027 (significantly higher in EIA+ than EIA- patients)

Repeat test NOT needed for the diagnosis of CDI if PCR is the method Robert F. Luo, Niaz Banaei (Stanford UMC) J. Clin. Microbiol :3738- Result following the first test with a negative result 293 patients (24% of all pts) 406 repeat tests (ave. 1.5/pt) PCR Sens 87.2%; Spec 98.6% 7 new TP’s at ≥7 days <1% repeat tests gave + result <7 days

Evaluation of the Cepheid Xpert Clostridium difficile Epi assay for diagnosis of Clostridium difficile infection and typing of the NAP1 strain at a cancer hospital Babady et al J Clin Microbiol 48: patients; 60 had 027. Compared to patients with non 027 strains, they were more likely to: ‒ Die by day 90 after diagnosis ‒ Be older and/or residents of a LTCF ‒ Be treated for a longer duration of time ‒ Have therapy switched from metro to vanco Age, ICU admission, Charlson score, and infection with 027 were significant predictors of mortality (hazard ratio 2.77)

In revision

EIA onlyGDH + EIAGDH + Xpert Xpert C. diff Sensitivity 58.3%55.6%86.1%94.4% Specificity 94.7%98.3%97.8%96.3% PPV 68.9%87.0%95.8%84.0% NPV 91.9%91.7%97.2%98.8%

C. diff PCR vs GDH in Clinical Trials for 027 vs Non-027 Isolates SensitivityP value RibotypeXpertGDH EIA 027 (11) 90.9% 1.0 Non-027 (36) 91.7%72.2% Tenover, et al JCM Vol. 48.

Detection of C. difficile Infection (CDI): Impact of Test Method on Infection Control Tenover FC et al. J. Molecular Diag. 2011; 13: Test Method Ave. Cost/ Test Sens No. of + Patients Missed not in Isolation Spec Pts in isolation with CDI Patients in isolation without CDI GDH/ EIA $1855%45 94% 5554 NAAT $3595%5 96% 9536 Assume 1000 patients are tested, 10% prevalence

Photo by Dr. Curtis Donskey (Case Western)

Environmental Control Issues (Am J Infect Control 2009;37:15-9.) (027/BI)  105 non-isolation rooms surveyed by culture  16% contaminated with toxin-producing C. difficile  Outside of patient rooms:  9 of 29 (31%) physician work areas positive  1 of 10 (10%) nurse work areas  9 of 43 (21%) piece of portable equipment  50% of strains typed were epidemic NAP1 strain

Patient Death vs Binary Toxin Bacci et al EID; 17: Binary + Non-027 Binary + A + B + Binary - Non-typed Relative risk of death in 30 days = 28% (RR ) vs 17% death from CDI with non-binary toxin producing strain

Recurrence Rates for Fidaxomicin vs. Vanco Louie et al Fidaxomicin versus Vancomycin for Clostridium difficile Infection. NEJM 364: For pts. with 027 strain, recurrence rates were higher with Fidaxomicin than Vanco. %recur-rence

Fecal transplant for CDI relapses or patients non-responsive to antibiotics  Bakken et al Treating Clostridium difficile Infection With Fecal Microbiota Transplantation. Clin. Gastroent. Hepatol. 9:1044–1049  van Nood et al Duodenal infusion of donor feces for recurrent Clostridium difficile. NEJM. 368: % cured Vanco V+bowel lavage V+BL+FMT Poopsickle

MRSA surveillance: some data about one approach

Patients are more ill with MRSA infections; more interventions, more resources 18,650 deaths in U.S.A. each year They cost more than infections with MSSA MRSA infections = longer length of stay $$$ Days in hospital How will preventing MRSA infections reduce costs?

MRSA Cost data (Duke Univ. Med. Ctr.) 2009 vol 4 pg:e8305 -e8305 Patients with MRSA infections were 30 x more likely to be readmitted and 7 times more likely to die within 90 days. Patients with MRSA infections cost $61,681 more than patients without infections and $38,000 more than with infections due to MSSA. Therefore: prevention of one MRSA infection will save the hospital >$61,000.

Evaluation of rapid screening and pre-emptive contact isolation for detecting and controlling methicillin-resistant Staphylococcus aureus in critical care: an interventional cohort study Harbarth et al Crit. Care Med.10: h TAT 22h TAT Pre-emptive Isolation (or <1 h TAT) Infected Colonized

Broth enriched culture results (48 hrs) Sensitivity ~same as PCR. Wolk et al. CA MS- Broth enriched orfX PCR MrsaSel “PCR is the improved gold standard..” JCM : 3933-

VA Hospital systems

59% decrease in MRSA HAIs Veterans Affairs Initiative to Prevent Methicillin- Resistant Staphylococcus aureus Infections Jain et al NEJM 364: % decrease in C. diff in non-ICUs 73% decrease in VRE infections in non-ICUs

Massachusetts General Hospital adopts automated system for MRSA surveillance A Randomized Controlled Trial Comparing Passive and Active Screening with Culture and Polymerase Chain Reaction. Shenoy et al. 2013, CID Sr. Author Dr. David Hooper >2000 tests per day !

Patients removed from isolation if MRSA negative by active surveillance Nasal swabs cultured for 48 hours on BD Chromagar Colonies confirmed by Gram stain and tube coagulase; –culture took 5 days to complete –PCR took <1 day to complete 457 patient included in the analysis –Completion of the protocol: 10% in non-intervention arm ( standard of care with no active enrollment) –Completion of protocol: 73% in intervention arm (i.e., all 3 cultures and PCR tests were collected) Results –66 patients in intervention arm were positive for MRSA in at least one culture; 60 were positive on the first culture, 3 on second, and 3 on third –Discontinuation of contact precautions was 4 times more likely in the intervention (active surveillance) arm

Cost Saving Through Discontinuation of Contact Precautions Screening Method Decrease in Contact Precaution Days Cost savings Passive screening with cultures 104$86,950 Active surveillance with cultures 418$349,472 Active surveillance with PCR 1,841$1,539, patients accounted for 3339 patient days of isolation