Tag Archives: Clostridium difficile

C Diff Foundation Welcomes Denise Graham, Strategic Advisor

We are pleased to welcome Denise Graham
to the C Diff Foundation.

Denise Graham, Founder and President of DDG Associates, formerly the Executive Vice President to the Association for Professionals in Infection Control (APIC) and Epidemiology, led the nation’s public reporting initiative thereby enabling her to work closely with all agencies falling under the U.S. Department of Health and Human Services.  Her expertise in this arena continues by assisting clients with ongoing changes such as value-based purchasing and guidelines coming from the Centers for Disease Control and Prevention (CDC).

With greater than twenty years of experience in the healthcare industry, Denise has formed key working relationships with numerous leading experts.

Denise comes to the C Diff Foundation as Strategic Advisor to assist the organization with greater visibility and continued growth in educating and advocating for C.difficile Infection prevention, treatments, environmental safety and support worldwide.

To contact Denise:, please e-mail her at:    denise@cdifffoundation.org

Rapid Detection of a C. difficile Toxins Through Laboratory Testing Accelerates Diagnosis and Treatment

Abstract

BACKGROUND:

Clostridium difficile is an anaerobic, spore-forming and Gram-positive bacillus. It is the major cause of antibiotic-associated diarrhea prevailing in hospital settings. The morbidity and mortality of C. difficile infection (CDI) has increased significantly due to the emergence of hypervirulent strains.

Because of the poor clinical different between CDI and other causes of hospital-acquired diarrhea, laboratory test for C. difficile is an important intervention for diagnosis of CDI.

OBJECTIVE:

Laboratory tests for CDI can broadly detect either the organisms or its toxins. Currently, several laboratory tests are used for diagnosis of CDI, including

toxigenic culture,

glutamate dehydrogenase detection,

nucleic acid amplification testing, cell cytotoxicity assay,

and enzyme immunoassay towards toxin A and/or B.

This review focuses on the rapid testing of C. difficile toxins and currently available methods for diagnosis of CDI, giving an overview of the role that the toxins rapid detecting plays in clinical diagnosis of CDI.

 

https://www.ncbi.nlm.nih.gov/pubmed/27601055

 

Pediatric Review Focused On Diagnostics Available for Clostridium Difficile, Colitis, and Colonoscopy

Abstract

PURPOSE OF THE REVIEW: Review tests available for detection of Clostridium difficile (C. Diff) induced disease, including when such tests should be done in children and how they should be interpreted.

RECENT FINDINGS: Multiple tests are available for detecting disease due to C. diff. These include colonoscopy and stool analysis. Colonoscopy with biopsy is the most sensitive test for detecting the presence of colitis. The toxins produced by the C. diff. (toxin A, toxin B, and binary toxin) are the agents that cause injury and disease. Only toxin producing C. diff. Strains will cause disease. Binary toxin by itself is not thought to produce disease. Binary toxin causes disease in humans when present with toxin A and B producing bacteria, and has been implicated with fulminant life threatening disease. Stool analyses vary in sensitivity and specificity depending on the assay used. The presence of toxin producing strains of C diff. in the stool does not equate with disease. The presence of a toxin-producing bacteria or toxins (A or B) only equates with disease if diarrhea or a diseased colon (toxic megacolon, ileus, and sepsis) is present. Nucleic acid amplification testing (NAAT), when used in the stool from patients with diarrhea, appears to be the most efficient study to detect the gene that encodes for toxin A and B and thus to diagnose C. diff.-induced disease. Infants have a high carriage rate of C. diff. and are believed not to develop disease from it or its toxins. Infants should not be tested for C. difficile. The NAAT is most specific when done on patients with diarrhea with liquid stools. Testing for C. difficile should only be done on patients with diarrhea. One can assume that a patient who has no diarrhea and is not ill does not have C. diff.-induced disease. Treatment should be limited to patients with diarrhea who test positive for C. diff. toxin (A or B) or toxin-producing bacteria. Direct testing for binary toxin is not commercially available. Binary toxin is only thought to cause disease in humans when C. diff. toxin (A and B)-producing bacteria are present.

McConnie R, et al. Curr Gastroenterol Rep. 2017.

 

To review Abstract in its full entirety please click on the following link:

https://www.ncbi.nlm.nih.gov/m/pubmed/28707191/

Changing the Bed Linens In Sickness and In Health

According to Microbiologist, Phillip Tierno of New York University

our bed linens can “quickly blossom into a botanical park of bacteria and fungus.”

If left for too long, the microscopic life within the wrinkles and folds of our bed sheets can even make us sick,

> We can recall – years ago – the bed linens in any acute care facility (e.g., hospital) the bed linens were changed daily.   Food for thought <<

 

Humans naturally produce roughly 26 gallons of sweat in bed every year. When it’s hot and humid outside, this moisture becomes what scientists call an “ideal fungal culture medium.”

In a recent study that assessed the level of fungal contamination in bedding, researchers found that a test sample of feather and synthetic pillows that were 1 1/2 to 20 years old contained as many as 16 species of fungus each.

And it’s not just your own microbial life you’re sleeping with. In addition to the fungi and bacteria that come from your sweat, sputum, skin cells, and vaginal and anal excretions, you also share your bed with foreign microbes.

These include animal dander, pollen, soil, lint, dust mite debris and feces, and finishing agents from whatever your sheets are made from, to name a few.

Tierno says all that gunk becomes “significant” in as little as a week. And unclean bedding still exposes you to materials that can trigger the sniffing and sneezing, since the microbes are so close to your mouth and nose that you’re almost forced to breathe them in.

“Even if you don’t have allergies per se, you can have an allergic response,” Tierno said.

Another reason your sheets get dirty quickly has little to do with your behavior or sweat patterns — the issue is simply gravity.

“Just like Rome over time was buried with the debris that falls from gravity, gravity is what brings all that material into your mattress,” Tierno said.

One to two weeks of this buildup is enough to leave anyone with a scratchy throat — especially those with significant allergies or asthma. (One in six Americans has allergies.)

“If you touched dog poo in the street, you’d want to wash your hands,” Tierno said.

“Consider that analogous to your bedding. If you saw what was there — but of course you don’t see it — after a while you have to say to yourself, ‘Do I want to sleep in that?’

So what does Dr. Tierno suggest?

To stem the invisible tide, he said, sheets should be washed once a week — >> More Often when bed linens are visibly soiled and an infection is being treated <<


Proper ways to handle soiled linens:

There is now a common understanding that linens, once in use, are usually contaminated and could be harboring microorganisms such as MRSA and VRE.

Further, the Centers for Disease Control and Prevention (CDC) cautions that healthcare professionals should “handle contaminated textiles and fabrics with a minimum agitation to avoid contamination of air, surfaces, and persons.” Even one of the leading nursing textbooks, Fundamentals of Nursing, states, “Soiled linen is never shaken in the air because shaking can disseminate secretions and excretions and the micro organisms they contain.” This text also states, “…linens that have been soiled with excretions and secretions harbor microorganisms … can be transmitted to others.”

According to Fundamentals of Nursing, when handling linens in any acute care and healthcare facility:

1. You should always wash your hands after handling a patient’s bed linens.

2. You should hold soiled linen away from your uniform.

3. Soiled linen is never shaken in the air because shaking can disseminate the micro-organisms they contain.

4. Linen from one patient’s bed is never (even momentarily) placed on another patient’s bed.

5. Soiled linens should be placed directly into a portable linen hamper or tucked into a pillowcase and the end of the bed before it is gathered up for disposal in the linen hamper or linen chute.

 

To read this article in its entirety – please click on the following link:

http://www.businessinsider.com/how-often-to-wash-bed-sheets-2017-6

 

June 2017 Newsletter

JUNE 2017 – NEWSLETTER

 


5th Annual International C. diff. Awareness

Conference & Health EXPO Updates

Welcome to the 5th Annual International C.diff. Awareness Conference & Health EXPO  second update.  The Conference & Health EXPO begins on November 9th at 8:00 a.m. and concludes on November 10th at 3:00 p.m. There are over twenty guest speakers, leading topic experts, sharing up-to-date data with an audience of health care professionals from a variety of management levels and specialties, medical educators, medical students, and professionals with shared interests. The venue is the University of Nevada Las Vegas (UNLV) Thomas and Mack Center in conjunction with the Embassy Suites Convention Center where staff and event coordinators are working together to create this amazing event.  Embassy Suite Convention Center hotel accommodations are now at a “limited availability.”  Please utilize the hotel reservation portal available on the conference page
We are truly grateful for the following Corporations and Sponsors of this educational conference, also exhibiting.
An educational grant has been awarded to the C Diff Foundation by
Sanofi Pasteur USA.  It is through their continued support that this event is made possible:
DIAMOND SPONSOR
Synthetic Biologics
GOLD SPONSORS
Roche
Clorox Healthcare
Rebiotix
Nestle Health Science
Seres Therapeutics
Xenex
SILVER SPONSORS
Tru-D
Surfacide
SporeGen
EDM – Environmental Disinfection Management
ADDITIONAL EXHIBITORS
Contagion Live
Just Ask Where Concierge
Safety Net
www.cdiffradio.com
Live Broadcasts on Tuesdays at:   
10a PT,    11a MT,   12p CT,    1p ET 
June 6th :   Global Sepsis Alliance
June 13th:   Kristopher Maday, PA
June 20th:   Home Care and C. diff.
June 27th:   Advocating In Healthcare

Baking For C.diff. Awareness

Volunteer Patient Advocates, with the
C Diff Foundation Members,  were busy in the kitchens baking across the globe to support our mission and provide education at each event.
We kicked off the month long chain of events with a successful recipe to educate and advocate for
C. difficile infection awareness worldwide.  More than 700 brochures were shared at the bake sales meeting  the goal –  promoting C. diff. infection prevention, treatments, environmental safety and support across the globe during the month long campaign.  Thank You to everyone involved making this campaign a global success.

Save the Date

On September 14th a day to  Honor the Professionals Dedicated to Clostridium difficile Research and Development. Their Efforts Bring Forth New Concepts, New Theories, and the Progress Towards A Better Understanding – Pursuing Future Developments In Clostridium difficile           (a.k.a., C.diffiicle, C.diff.).
September 14th,   8:00 a.m. – 12:00 p.,m. ET
This free, live webinar by C.diff. Science, is to honor Professionals in the Science community, leading the way advancing C. difficile Infection Prevention, Treatments, and Environmental Safety Products worldwide  –  hosted by the C Diff Foundation –  a slate of industry leaders and medical researchers — from highly regarded health systems — share their journeys and efforts focused on Clostridium difficile research and development that will be appreciated by colleagues, fellow-researchers, and the scientific teams within organizations.
 
Visit cdiffscience.org To View the Guest Speakers, Presentation Topics.
Register For This One Day Educational Event and Don’t Forget To Share the News.
June  9     Scott Battles: C. diff. Q & A
June 15    Karen Factor,RD, Nutrition
June 19    Lisa Hurka-Covington, Anxiety
June 20    Roy Poole, CO  C. diff. Q & A
June 26    Dr.Oneto,MD  and
                 Dr.Feuerstadt,MD
                 C. diff. – The What,Where,How.
                   Sign up today
Where Support Is Just a Phone Call Away ♥ 

Support and information sessions are for everyone especially for —

  • Patients and their Families.
  • Clinicians,
  • C. diff. survivors continuing their recovery from a prolonged illness.
  • Patients working their way through any long-term wellness draining diagnosis.
Sessions are accessible from the USA and
57 Countries

Connect with others being treated for and recovering from a C.diff. Infection.

Ask questions, get advice & support.
Sign up FREE

www.cdifffoundation.org/support/

Treasure Island, FL Community EXPO Promoting

 C.diff. Awareness

It was a pleasure joining the local residents of Treasure Island, Florida on May 18th.  Educating and Advocating for C. difficile infection prevention, treatments, and environmental safety, a shared goal to witness a decline in newly diagnosed
C. diff. cases worldwide.  To view upcoming events of interest, please visit www.cdifffoundation.org/events-of-interest/
“None of us can do this alone, all of us can do this together.” 
C Diff Foundation
6931 ian Ct  #14
New Port Richey, FL 34653
(919) 201-1512
See what’s happening on our social sites:
C Diff Foundation | 6931 Ian Ct #14, New Port Richey, FL 34653
 

C diff Infection Compared Control in 6 United Kingdom Hospitals With Whole-Genome Sequencing (WGS)

David W. Eyre
Warren N. Fawley
Anu Rajgopal
Christopher Settle
Kalani Mortimer
Simon D. Goldenberg
Susan Dawson
Derrick W. Crook
Tim E. A. Peto
A. Sarah Walker

.

Clin Infect Dis cix338.
Published:
29 May 2017 

Abstract

Background Variation in Clostridium difficile infection (CDI) rates between healthcare institutions suggests overall incidence could be reduced if the lowest rates could be achieved more widely.
Methods.

We used whole-genome sequencing (WGS) of consecutive C. difficile isolates from 6 English hospitals over 1 year (2013–14) to compare infection control performance. Fecal samples with a positive initial screen for C. difficile were sequenced. Within each hospital, we estimated the proportion of cases plausibly acquired from previous cases.

Results.

Overall, 851/971 (87.6%) sequenced samples contained toxin genes, and 451 (46.4%) were fecal-toxin-positive. Of 652 potentially toxigenic isolates >90-days after the study started, 128 (20%, 95% confidence interval [CI] 17–23%) were genetically linked (within ≤2 single nucleotide polymorphisms) to a prior patient’s isolate from the previous 90 days. Hospital 2 had the fewest linked isolates, 7/105 (7%, 3–13%), hospital 1, 9/70 (13%, 6–23%), and hospitals 3–6 had similar proportions of linked isolates (22–26%) (P ≤ .002 comparing hospital-2 vs 3–6). Results were similar adjusting for locally circulating ribotypes. Adjusting for hospital, ribotype-027 had the highest proportion of linked isolates (57%, 95% CI 29–81%). Fecal-toxin-positive and toxin-negative patients were similarly likely to be a potential transmission donor, OR = 1.01 (0.68–1.49). There was no association between the estimated proportion of linked cases and testing rates.

Conclusions.

WGS can be used as a novel surveillance tool to identify varying rates of C. difficile transmission between institutions and therefore to allow targeted efforts to reduce CDI incidence.

To view the article in its entirety please click on the following link:

Preventing Clostridium difficile infection (CDI) is a priority for infection control teams, as it remains a major healthcare-associated infection; although the incidence of healthcare-associated CDI in the United Kingdom has fallen to 1.5 per 10000 inpatient bed-days [1], rates across Europe range from 0.7 to 28.7/10000 bed-days [2], and there were an estimated 293000 healthcare-associated cases in the United States in 2011 [3].

Variation in CDI incidence across countries and between healthcare institutions [4] suggests overall incidence could be reduced if the lowest rates could be achieved more widely. Surveillance programs [5] and penalties for healthcare institutions [6] have been implemented to promote reductions. However, robustly identifying the best performing institutions is challenging.

Variations in true incidence can arise from differences in patient risk factors or locally circulating strains. However, testing strategy also influences reported incidence; reported CDI incidence is associated with testing rates [2]. With low testing rates, CDI ascertainment is likely to be suboptimal. Conversely, high testing rates may lead to overdiagnosis, for example, from testing C. difficile colonized patients, who do not have CDI but may have diarrhea of another cause.

The lack of a universally accepted objective CDI case definition means that robust comparisons of infection rates between institutions should ideally also consider independent measures of which patients are being tested to assess the comparability of differing testing strategies [7].

Additionally, assessing potential sources of healthcare- attributed CDI cases [8] is complex, requiring differentiation between lapses in infection control around symptomatic cases or more generally, deviation from optimal antimicrobial stewardship, and external factors, for example, the food chain. Healthcare exposure increases the risk of C. difficile acquisition; both CDI and colonization increase during hospital stay [9]. However, despite this strong association, studies using whole-genome sequencing (WGS) [10–12] and other genotyping schemes [13–15] have shown that, in endemic settings with standard infection control, only the minority of infections are likely to have been acquired from other hospitalized CDI cases. However, the extent to which this proportion of linked cases varies between hospitals is unknown. Furthermore, such potential variance in linkage rates could identify a potentially preventable group of CDIs.

We investigated variation in the proportion of linked cases using WGS of consecutive C. difficile isolates from 6 hospitals in England and explored whether this could be used to assess their infection control effectiveness, by assessing the proportion of cases plausibly acquired from (linked to) previous cases.

METHODS

Samples and Settings

Hospitals in England are recommended to store frozen aliquots of C. difficile–positive fecal samples for 12 months [16]. Stored consecutive hospital and community diarrheal samples submitted for routine C. difficile testing at 6 hospital laboratories were studied, including a tertiary referral center and teaching hospital, and 5 district general hospitals serving a mix of urban and rural populations (see Supplement). Samples were obtained for a one-year period at each hospital between January 2013 and October 2014. Results were anonymized by assigning a computer-generated random identifier, hospital 1 to hospital 6.

Each hospital used the United Kingdom-recommended 2-stage C. difficile testing algorithm [17]. Hospital 1 used toxin gene polymerase chain reaction (PCR) as a screening test, hospital 2 both glutamate dehydrogenase (GDH) enzyme immunoassay (EIA) and toxin gene PCR as a combined screening test, and hospitals 3–6 a GDH screen. Screen-positive samples underwent confirmatory fecal-toxin EIA testing. Screen-positive, fecal-toxin-positive patients were regarded as having CDI. Toxin gene PCR was also performed as a third-line test on all GDH-positive samples at hospitals 3 and 6, and on samples from inpatients at hospital 5. PCR-positive, fecal-toxin-negative patients, with a clinical syndrome in keeping with CDI, were regarded as potential cases for treatment and infection control purposes.

All screen-positive fecal samples were sent to Leeds General Infirmary microbiology laboratory, United Kingdom (except hospital 2, which submitted isolates and excluded toxin EIA-negative/PCR-negative samples), where they underwent selective culture for C. difficile [18] and capillary electrophoresis ribotyping [19]. Individual patient consent for use of anonymized bacterial isolates was not required.

Sequencing

DNA was extracted from subculture of a single colony from each culture-positive sample and sequenced using Illumina HiSeq2500. Sequence data were processed as previously (see Supplement) [10, 20], mapping sequenced reads to the C. difficile 630 reference genome [21]. Sequences were compared using single-nucleotide polymorphisms (SNPs) between sequences obtained from maximum-likelihood phylogenies [22], corrected for recombination [23]. Potentially toxigenic strains were identified as those containing toxin genes using BLAST searches of de novo [24] assemblies.

Analysis

For each sample, only the hospital, collection date, and fecal-toxin EIA result were known; no further epidemiological data were available. Within each hospital, sequences were compared with all sequences from samples obtained in the prior 90 days. Samples from the community and hospital were included to increase the chance of identifying transmission events occurring in hospital but leading to CDI onset after discharge. From previous estimates of C. difficile evolution and within-host diversity [10, 25, 26], ≤2 SNPs are expected between isolates linked by transmission within 90 days. Therefore, where ≥1 prior sequences within ≤2 SNPs were identified, a case was considered to have been potentially acquired from another case. A 90 day threshold for linking cases was chosen assuming that cases were rapidly treated and infectiousness declined, and that subsequent cases related by direct transmission occurred within incubation periods implied by surveillance definitions [8] and previous studies [13]. As the sources of cases occurring at the start of the study may themselves have been sampled before the study started, the proportion of cases linked to a prior case was only calculated for cases occurring after the first 90 days, with cases in the first 90 days included only as potential sources for subsequent cases.

Two differing case definitions were considered. Initially, all patients with culture-positive potentially toxigenic C. difficile were considered “cases” to capture possible transmission events involving potentially toxigenic C. difficile irrespective of fecal-toxin status. The analysis was then repeated restricted only to fecal-toxin-positive CDI cases. For comparisons with previously published data, the same definition and analysis approach was applied to fecal-toxin-positive CDI cases occurring within 90 days in Oxford (September 2007 to December 2010, split by calendar year) [10] and Leeds (August 2010 to April 2012) [11].

Risk Factor Analysis

Univariate logistic regression was used to determine whether a case’s toxin status affected the risk of it being genetically related to a prior case, that is, potentially acquired from another case. Similarly, logistic regression was used to determine whether a case’s fecal-toxin status affected the risk of it being genetically linked to a subsequent case, that is, to assess the relative infectiousness of fecal-toxin-positive and toxin-negative patients.

To assess whether the locally circulating strain mix affected transmission estimates, hospital-specific estimates were adjusted for ribotype using multivariate logistic regression (see Supplement).

Simulations

To estimate the impact of missing data (as not all sampled cases were sequenced at some hospitals), we simulated transmission at a theoretical hospital. We subsampled simulated cases and calculated the change in the percentage of cases linked to a prior case as the proportion of missing samples increases (details in Supplement).

METHODS

Samples and Settings

Hospitals in England are recommended to store frozen aliquots of C. difficile–positive fecal samples for 12 months [16]. Stored consecutive hospital and community diarrheal samples submitted for routine C. difficile testing at 6 hospital laboratories were studied, including a tertiary referral center and teaching hospital, and 5 district general hospitals serving a mix of urban and rural populations (see Supplement).

Samples were obtained for a one-year period at each hospital between January 2013 and October 2014. Results were anonymized by assigning a computer-generated random identifier, hospital 1 to hospital 6.

Each hospital used the United Kingdom-recommended 2-stage C. difficile testing algorithm [17].

Hospital 1 used toxin gene polymerase chain reaction (PCR) as a screening test,

Hospital 2 both glutamate dehydrogenase (GDH) enzyme immunoassay (EIA) and toxin gene PCR as a combined screening test, and hospitals 3–6 a GDH screen.

Screen-positive samples underwent confirmatory fecal-toxin EIA testing. Screen-positive, fecal-toxin-positive patients were regarded as having CDI. Toxin gene PCR was also performed as a third-line test on all GDH-positive samples at hospitals 3 and 6, and on samples from inpatients at hospital 5. PCR-positive, fecal-toxin-negative patients, with a clinical syndrome in keeping with CDI, were regarded as potential cases for treatment and infection control purposes.

All screen-positive fecal samples were sent to Leeds General Infirmary microbiology laboratory, United Kingdom (except hospital 2, which submitted isolates and excluded toxin EIA-negative/PCR-negative samples), where they underwent selective culture for C. difficile [18] and capillary electrophoresis ribotyping [19]. Individual patient consent for use of anonymized bacterial isolates was not required.

Sequencing

DNA was extracted from subculture of a single colony from each culture-positive sample and sequenced using Illumina HiSeq2500. Sequence data were processed as previously (see Supplement) [10, 20], mapping sequenced reads to the C. difficile 630 reference genome [21]. Sequences were compared using single-nucleotide polymorphisms (SNPs) between sequences obtained from maximum-likelihood phylogenies [22], corrected for recombination [23]. Potentially toxigenic strains were identified as those containing toxin genes using BLAST searches of de novo [24] assemblies.

Analysis

For each sample, only the hospital, collection date, and fecal-toxin EIA result were known; no further epidemiological data were available. Within each hospital, sequences were compared with all sequences from samples obtained in the prior 90 days. Samples from the community and hospital were included to increase the chance of identifying transmission events occurring in hospital but leading to CDI onset after discharge. From previous estimates of C. difficile evolution and within-host diversity [10, 25, 26], ≤2 SNPs are expected between isolates linked by transmission within 90 days. Therefore, where ≥1 prior sequences within ≤2 SNPs were identified, a case was considered to have been potentially acquired from another case. A 90 day threshold for linking cases was chosen assuming that cases were rapidly treated and infectiousness declined, and that subsequent cases related by direct transmission occurred within incubation periods implied by surveillance definitions [8] and previous studies [13]. As the sources of cases occurring at the start of the study may themselves have been sampled before the study started, the proportion of cases linked to a prior case was only calculated for cases occurring after the first 90 days, with cases in the first 90 days included only as potential sources for subsequent cases.

Two differing case definitions were considered. Initially, all patients with culture-positive potentially toxigenic C. difficile were considered “cases” to capture possible transmission events involving potentially toxigenic C. difficile irrespective of fecal-toxin status. The analysis was then repeated restricted only to fecal-toxin-positive CDI cases. For comparisons with previously published data, the same definition and analysis approach was applied to fecal-toxin-positive CDI cases occurring within 90 days in Oxford (September 2007 to December 2010, split by calendar year) [10] and Leeds (August 2010 to April 2012) [11].

Risk Factor Analysis

Univariate logistic regression was used to determine whether a case’s toxin status affected the risk of it being genetically related to a prior case, that is, potentially acquired from another case. Similarly, logistic regression was used to determine whether a case’s fecal-toxin status affected the risk of it being genetically linked to a subsequent case, that is, to assess the relative infectiousness of fecal-toxin-positive and toxin-negative patients.

To assess whether the locally circulating strain mix affected transmission estimates, hospital-specific estimates were adjusted for ribotype using multivariate logistic regression (see Supplement).

Simulations

To estimate the impact of missing data (as not all sampled cases were sequenced at some hospitals), we simulated transmission at a theoretical hospital. We sub-sampled simulated cases and calculated the change in the percentage of cases linked to a prior case as the proportion of missing samples increases (details in Supplement).

RESULTS

Consecutive samples sent for C. difficile testing at 6 hospitals were studied for 12 months (Table 1). In total, 1052/1098 (96%) of GDH/toxin-PCR screen-positive samples were available: 95/98 (97%) at hospital 1, 144/178 (81%) at hospital 2, 118/127 (93%) at hospital 5 and otherwise 100%. 974/1052 (93%) available samples were confirmed as C. difficile on culture. For the 5 hospitals with available testing data, 887/21539 (4.1%) of samples submitted for testing were culture-positive (Table 1); 971/974 (99.7%) culture-positive samples were successfully sequenced. Of sequenced culture-positive samples, 451/971 (46.4%) were EIA fecal-toxin-positive, 35–71% by hospital. By contrast, 851/971 (87.6%) were potentially toxigenic, that is, had toxin genes detected via sequence data. Hence, 400/851 (47.0%) samples containing potentially toxigenic C. difficile did not have fecal-toxin detected. In the 971 sequenced isolates, the most common ribotypes identified were 014, 015, 005, 002, 020, and 078 (Table 2). Ribotype-027(NAP1/ST-1) only accounted for 16 (2%) cases.

To view graphs and tables, please click the following link:

https://academic.oup.com/cid/article/doi/10.1093/cid/cix338/3857742/Comparison-of-Control-of-Clostridium-difficile

Relatedness to Prior Cases

The proportion of cases plausibly linked to a prior case by recent transmission varied by hospital. Of 851 sequenced potentially toxigenic cases, all were considered as potential sources of infection, but only the 652 obtained after the first 90 days of sampling at each hospital were assessed for linkage to a previous case. Across the 6 hospitals, 128/652 (20%, 95% confidence interval [CI] 17–23%) potentially toxigenic cases were genetically linked to a prior case from the previous 90 days. Hospital 2 had the fewest cases linked to a prior case, 7/105 (7%, 3–13%), hospital 1 had an intermediate number, 9/70 (13%, 6–23%), and hospitals 3–6 had similar numbers of linked cases, 37/153 (24%, 18–32%), 32/134 (24%, 17–32%), 18/76 (24%, 15–35%), and 25/113 (22%, 15–31%), respectively. Hospital 2 had significantly fewer linked cases than hospitals 3–6 (P ≤ .002), with weaker evidence for lower rates in hospital 1 than hospitals 3, 4, and 5 (P = .05, .07, .09, respectively). Overall, 48/128 (38%) of potential transmission recipients were fecal-toxin-negative (11–68% across hospitals, Figure 1A). Fecal-toxin detection in a recipient was associated with increased odds of having a potential transmission donor, odds ratio 1.67 (95% CI 1.12–2.48, P = .01).

 

In total, 59/128 (46%) putative transmission recipients were only linked to ≥1 fecal-toxin-positive potential donors, 50 (39%) to only fecal-toxin-negative donors, and 19 (15%) to both toxin-positive and toxin-negative donors. Considering the 667 cases occurring in the first 270 days at each hospital, that is, the cases with an opportunity to transmit to a sampled case within the next 90 days, 120 (18%) were potential donors. Fecal-toxin-positive and -negative cases were similarly infectious: the odds ratio for a fecal-toxin- positive case, compared to a fecal-toxin-negative case, being a potential transmission donor was 1.01 (95% CI 0.68–1.49, P = .97).

When only considering transmission to and from fecal- toxin-positive cases, fewer cases were genetically linked to a previous case within 90 days, 51/335 (15%, 95% CI 12–20%). We observed a different “ranking” of hospitals compared with the above analysis of linkage rates based on potentially toxigenic isolate-positive patients: hospital 3 had the greatest proportion of fecal-toxin-positive cases genetically related to a prior fecal-toxin-positive case, 31% (22–41%), and hospital 6 the lowest, 0% (0–9%) (Figure 1B).

Results were similar to those for all potentially toxigenic C. difficile (Figure 1A) if all C. difficile sequences, nontoxigenic as well as potentially toxigenic, were considered (Figure 1C). Considering only nontoxigenic isolates, very similarly to potentially toxigenic isolates, 19/96 (20%, 95% CI 12–29%) were genetically linked to a prior patient isolate from the previous 90 days.

There was no evidence that the number of linked cases varied during the study at any hospital (Figure 1D). Because different numbers of sequences were obtained from the different hospitals, we investigated how this affected the estimated proportions of cases linked to a prior case. Estimated proportions of linked cases were relatively stable once approximately 50 cases had been sequenced (Figure 2).

Impact of Testing Frequency

The proportion of originally tested samples that were stored and then culture-positive was similar across the 5 hospitals with testing data, 3.8%–4.3% (P = .89, Table 1). In contrast, testing rates ranged from 98 to 239 samples per 10000 bed-days. There was no association between the estimated proportion of cases linked to a previous case within 90 days and testing rates (P = .19 for all potentially toxigenic cases, Figure 3A, and P = .60 for fecal-toxin-positive cases only, Figure 3B). For comparison, Figure 3B also displays rates of linked cases for previously published data from Oxford and Leeds.

Figure 2:  Proportion of potentially toxigenic cases linked to a previous potentially toxigenic case by hospital and number of sequences obtained. Abbreviation: SNP, single-nucleotide polymorphism.

Adjustment for Ribotype

After adjustment for locally circulating ribotypes, estimates of the proportion of potentially toxigenic cases related to a previous potentially toxigenic case within ≤2 SNPs and ≤90 days remained largely unchanged (Figure 4A). Using the same model, per-ribotype estimates for the proportion of related cases, adjusted for differences across hospitals, showed more variation (Figure 4B, Table 2 for unadjusted proportions). Ribotype-027 had significantly more related cases (adjusted proportion, 57%, 95% CI 29–81%, n = 12) than the comparison group of all other ribotypes (11%, 7–18%, P = .002, n = 124), as did ribotype-002 (25%, 15–38%, P = .04, n = 53), 012 (50%, 29–71%, P = .001, n = 22), and 087 (44%, 23–67%, P = .005, n = 18).

Adjustment for Completeness of Testing

As only 144/178 (81%) of GDH-positive samples at hospital 2 were retrievable for culture we assessed the likely impact of these missing samples on the estimated proportion of linked cases by simulating transmission and sampling at a theoretical hospital (Figure S1). As sampling becomes increasingly less complete, the estimated proportion of linked cases declines proportional to the probability of a case being sampled. Applying our simulation to hospital 2 provides a revised estimate of 8% of cases being linked to a prior case (see Supplement for details).

……………………….

DISCUSSION

Here, we demonstrate the value of WGS as a tool to estimate different rates of C. difficile transmission across institutions. Sequencing consecutive C. difficile isolates from routine testing over one year, we found transmission rates varied between 6 hospitals. Considering all patients with potentially toxigenic C. difficile, irrespective of fecal-toxin status, in the best performing hospital only 7% of patients’ isolates were sufficiently genetically related to a previous isolate from another patient to support transmission (8% adjusting for incomplete sampling). By contrast, approximately 3–4-fold more isolates (22–26%) were related in 4 of the other hospitals. These results remained similar after adjusting for the locally circulating strains.

Restricting to only patients with fecal-toxin-positive CDI, we confirmed previous findings that only a minority of CDI cases arise from contact with another symptomatic case: 35% in Oxford [10], 35% in Leeds [11], and 37% of ribotype-027 cases in Liverpool [12], were genetically linked to a previous case, with only a subset of these cases sharing time and space on the same hospital ward.

Applying the criteria for linking cases used in the present study to the Oxford and Leeds data sets, 38% of cases in Oxford were linked to a previous case in 2008 falling to 19% in 2010, and 30% of cases were similarly linked in Leeds. Across the 6 study hospitals, serving a range of populations, toxin-positive CDI linkage rates were all <15% with the exception of hospital 3, where 31% of cases were linked. It is likely the lower linkage rates in the current study in part reflect the falling incidence of ribotype-027 [11], associated with more onward transmission in this study, likely as a result of national fluoroquinolone restriction [27] but may also represent changes in infection prevention and control practice.

Our findings also support the recently reported role in transmission of GDH-positive patients with toxigenic C. difficile, but no detected fecal-toxin [28]. By sequencing all GDH-positive cases, we were able to compare the probability of fecal-toxin-positive and toxin-negative patients being potential sources of transmission, that is, having C. difficile genetically linked to a subsequent C. difficile isolate in another patient. Fecal-toxin-negative patients were similarly infectious to fecal-toxin-positive patients: fecal-toxin status did not affect the odds of being a potential transmission source. Strategies to identify and institute infection control measures around patients with potentially toxigenic C. difficile without detected fecal-toxin are therefore likely to reduce overall CDI incidence, although may be more costly, for example if toxin gene PCR is used as an initial screen rather than GDH EIA. Toxin-positive patients, that is, CDI cases, were more likely to have an identified potential transmission donor, than toxin-negative patients. This is in keeping with previous observations that recent C. difficile acquisition is associated with increased risk of disease, whereas long-term carriage is relatively protective [29].

It is likely that differing clinical CDI testing thresholds applied across the study hospitals, despite each being guided by national recommendations; notably, testing rates varied more than 2-fold between hospitals (98–239 tests/10000 bed-days). However, despite this variation, the overall proportion of samples tested that were C. difficile culture-positive was very similar across hospitals (~4%). These 2 findings combined resulted in varying rates of potentially toxigenic C. difficile isolation, 4.2–8.2/10000 bed-days, and varying (fecal-toxin-positive) CDI rates, 1.8–5.7/10000 bed-days. As the proportion of samples that were C. difficile culture-positive was close to reported community asymptomatic C. difficile colonization rates (~4%), and lower than reported colonization rates in asymptomatic hospital inpatients, (~10%) [30], it is possible that the higher reported CDI rates in some study hospitals may reflect overascertainment; independent assessment of which symptomatic patients are tested for CDI would be required to resolve this with certainty [7]. As designed, the study did not measure the extent of transmission involving asymptomatic patients, and therefore it is likely that not all hospital-associated transmission is captured. However, as this was the case for all hospitals, comparisons can still be made between hospitals and with previous studies investigating symptomatic patients.

Interestingly, we did not find any evidence of a relationship between rates of C. difficile testing and proportions of cases that could be linked to a previous case. Differing sampling/testing will likely mean the study populations at each hospital varied, for example with some institutions potentially more likely to include milder CDI cases than others. It should also be noted that differences in the population sampled by a particular testing strategy may affect the proportion of cases linked differently to incomplete sampling of a given population. We quantified the impact of the latter through simulation. Unfortunately, incomplete sampling could appear very similar to the impact of good infection control, as both results in low proportions of linked cases. One study limitation is that we only sequenced 81% GDH-positive samples at hospital 2. However, we demonstrate it may be possible to adjust for incomplete sampling, providing missed cases as assumed missing at random, and the number of onward transmissions from each case was random.

Both a limitation and a strength of our approach is that it relies only on sequencing laboratory samples and sampling dates. We demonstrate this allows comparative hospital surveillance with very limited, and no personal, sensitive or confidential, data. However, without ward admission and patient contact data, it is possible some genetically linked cases do not represent direct transmission from other cases. Genetic links might also arise through indirect healthcare-associated transmission via unsampled hosts or the hospital environment. Additionally, a minority of cases, without healthcare exposure in the last 90 days, may still have been genetically linked. However, there is no obvious reason why genetically related community C. difficile exposures, and therefore the proportion of such cases linked, should vary across England at a population level, even if other CDI risk factors do vary geographically, for example, antimicrobial use. Therefore, although we analyze transmission within the populations served by each hospital, as most CDI cases have recent healthcare exposure, the overall proportion of linked cases is still likely to be a reasonable combined indicator of infection control performance around cases and more generally. Without patient-level identifiers some repeat tests from the same patient may have been wrongly assigned as transmission events; however, we anticipate this was uncommon; repeat testing within 28 days is discouraged in national guidelines [17], and such samples are frequently not routinely processed.

Our method of comparing infection control performance depends on culturing C. difficile, which is not routinely undertaken, and on sequencing at least 6 months of samples, at around US$100 per sample. However, if samples are stored, as recommended in England, C. difficile could be cultured and sequenced retrospectively if increased incidence was noted and then continued prospectively to monitor the impact of any interventions. The cost-effectiveness of such an approach needs further evaluation.

In summary, here we present a novel method that enables assessment of the extent of hospital-acquired infection transmission within healthcare institutions. This approach revealed differences in CDI transmission rates across 6 English hospitals. It demonstrates the potential of whole-genome sequencing as a nationwide tool to identify institutions with excellent and also suboptimal infection control and therefore has the potential to allow targeted efforts to reduce CDI incidence.

Resources:  https://academic.oup.com/cid/article/doi/10.1093/cid/cix338/3857742/Comparison-of-Control-of-Clostridium-difficile

This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.

Clostridium difficile (C.diff.) a Spore Forming Bacteria

Types of spore forming bacteria.

To provide a background and definition of  each of them the following information is beneficial.

Bacteria are a large group of microscopic, unicellular organisms that exist either independently or as parasites. Some bacteria are capable of forming spores around themselves, which allow the organism to survive in hostile environmental conditions. Bacterial spores are made of a tough outer layer of keratin that is resistant to many chemicals, staining and heat. The spore allows the bacterium to remain dormant for years, protecting it from various traumas, including temperature differences, absence of air, water and nutrients. Spore forming bacteria cause a number of diseases, including botulism, anthrax, tetanus and acute food poisoning. (1)

Bacillus

Bacillus is a specific genus of rod-shaped bacteria that are capable of forming spores. They are sporulating, aerobic and ubiquitous in nature. Bacillus is a fairly large group with many members, including Bacillus cereus, Bacillus clausii and Bacillus halodenitrificans. Bacillus spores, also called endospores, are resistant to harsh chemical and physical conditions. This makes the bacteria able to withstand disinfectants, radiation, desiccation and heat. Bacillus are a common cause of food and medical contamination and are often difficult to eliminate.

Clostridium

Clostridium are rod-shaped, Gram-positive (bacteria that retain a violet or dark blue Gram staining due to excessive amounts of peptidoglycan in their cell walls) bacteria that are capable of producing spores. According to the Health Protecton Agency, the Clostridium genus consists of more than a hundred known species, including harmful pathogens such as Clostridium botulinum, Clostridium difficile, Clostridium perfringens, Clostridium tetani and Clostridium sordellii.

Some species of the bacteria are used commercially to produce ethanol (Clostridium thermocellum), acetone (Clostridium acetobutylicum), and to convert fatty acids to yeasts and propanediol (Clostridium diolis).

Background:

Scientists discovered C. diff in 1935, but they didn’t recognize it as the major cause of antibiotic-associated diarrhea until 1978. The rise of C. diff in the 1970s was triggered by the widespread use of the antibiotic clindamycin. Over the next 20 years, broad-spectrum antibiotics in the penicillin and cephalosporin families fueled the C. diff epidemic, and in the early years of this century, fluoroquinolone antibiotics were linked to a new and more dangerous hypervirulent strain of C. diff.

C. diff is classified as an anaerobic bacterium because it thrives in the absence of oxygen. Like its cousins, the Clostridia that cause tetanus, botulism, and gas gangrene, C. diff passes through a life cycle in which the actively dividing form transforms itself into the spore stage. Spores are inert and metabolically inactive, so they don’t cause disease. At the same time, though, spores are very tough and sturdy; they are hard to kill with disinfectants, and they shrug off even the most powerful antibiotics.

Here’s how C. diff causes trouble. Patients with C. diff shed spores into their feces. Without strict precautions, spores are inadvertently transmitted to hands, utensils, and foods, and then swallowed by someone else. The spores come to life in the second person’s GI tract, but in the best of circumstances, the normal bacteria keep C. diff in check and illness does not develop. But if the “good” GI bacteria have been knocked down by antibiotics, C. diff gets the upper hand. As C. diff multiplies and grows, it produces toxins that injure the lining of the colon, producing diarrhea, inflammation, and sometimes worse. Ordinary strains of C. diff produce two toxins, called toxins A and B, but the new, worrisome hypervirulent strains produce up to 16 times more toxin A and 23 times more toxin B. (2)

C. diff is an old bacterium,…..the CDAD epidemic is new ……..What turned a medical curiosity into a major threat? In a word, antibiotics.

Antibiotics are marvelous medications, and they are obviously here to stay. But doctors must use them wisely. That means prescribing an antibiotic only when it’s truly necessary, choosing the simplest, most narrowly focused drug that will do the job, and stopping treatment as soon as the job is done. Patients can help by resisting the temptation to demand an antibiotic for every potential infection.

When it comes to using antibiotics properly, less can be more.

Sporolactobacillus

Sporolactobacillus is a group of anaerobic, rod-shaped, spore forming bacteria that include Sporolactobacillus dextrus, Sporolactobacillus inulinus, Sporolactobacillus laevis, Sporolactobacillus terrae and Sporolactobacillus vineae. Sporolactobacillus are also known as lactic-acid bacteria for they are capable of producing the acid from fructose, sucrose, raffinose, mannose, inulin and sorbitol. Sporolactobacillus are found in the soil and often in chicken feed. According to “Fundamentals of Food Microbiology,” the spores formed by Sporolactobacillus are less resistant to heat than those formed by the Bacillus genus.

Sporosarcina

Sporosarcina are a group of round-shaped (cocci) aerobic bacteria that include Sporosarcina aquimarina, Sporosarcina globispora, Sporosarcina halophila, Sporosarcina koreensis, Sporosarcina luteola and Sporosarcina ureae. According to “Antibiotic Resistance and Production in Sporosarcina ureae,” Sporosarcina is thought to play a role in the decomposition of urea in the soil.

#########

Revival and Identification of Bacterial Spores in
25- to 40-Million-Year-Old Dominican Amber
Raid J. Cano* and Monica K. Borucki

A bacterial spore was revived, cultured, and identified from the abdominal contents of extinct bees preserved for 25 to 40 million years in buried Dominican amber. Rigorous surface decontamination of the amber and aseptic procedures were used during the recovery of the bacterium. Several lines of evidence indicated that the isolated bacterium was of ancient origin and not an extant contaminant. The characteristic enzymatic, biochemical, and 1 6S ribosomal DNA profiles indicated that the ancient bacterium is most closely related to extant Bacillus sphaericus.

To read the article in its entirety please click on the following link:

http://science.sciencemag.org/content/268/5213/1060.long

 

Sources:

(1)   http://Sciencing.com/types-spore-forming-bacteria-2504.html

(2) http://www.health.harvard.edu/staying-healthy/clostridium-difficile-an-intestinal-infection-on-the-rise