C. difficile – Credit CDC PHIL
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While novel viruses like nCoV and H7N9 have captured the bulk of our attention over the past few weeks, they certainly aren’t alone in their ability to mutate, and cause serious illness in humans.
Bacteria – while not as transmissible – can be every bit as deadly, and difficult to treat, as any emerging virus.
One notorious example is a nasty Gram-Positive bacteria called Clostridium difficile – or C. diff – an intestinal infection which claims tens of thousands of lives each year, and – as the name implies – is very difficult to treat
Usually brought on by the use of antibiotics - which kill off good gut bacteria along with the bad guys – C. diff can produce prolonged, and often life threatening bouts of diarrhea (see Unnecessary Antibiotic Use & C. Difficile Infections).
Last fall, in The Flight Of The Bacterial Intruder, we looked at how easily bacteria like C. diff, E. coli, and S. aureus can spread in a hospital environment. In 2010, we saw a study that found the more roommates you have during a hospital stay, the greater chance you will have of contracting an HAI (Healthcare Associated Infection) like MRSA or C. Diff.
Despite some promising new treatments on the horizon (see Maryn McKenna On Regulatory Obstacles To Fecal Transplants), the CDC warns:
While most types of HAIs are declining, one – caused by the germ C. difficile – remains at historically high levels. C. difficile causes diarrhea linked to 14,000 American deaths each year. Those most at risk are people, especially older adults, who take antibiotics and also get medical care.
Which brings us to a recent report from Health Protection Scotland of a new and deadly strain of C. diff which claimed two lives in one Scottish Hospital around the start of the New Year, and a third in another facility in April.
All three patients had serious co-morbidities which probably contributed to their demise. Other than sharing this newly identified strain, no epidemiological link between the cases in the two hospitals has been established.
01 May 2013
Emergence of novel C. difficile PCR ribotype 332
HPS has been alerted to a novel PCR ribotype of Clostridium difficile, designated ribotype 332, which was isolated from two patients cared for in the same clinical setting and diagnosed with C. difficile infection (CDI) in December 2012 and January 2013. Further genetic analysis carried out by the Scottish Salmonella, Shigella and Clostridium difficile Reference Laboratory (SSSCDRL) has shown that the strains from both patients were closely related.
As of April 2013, a further case of CDI with PCR ribotype 332 has been reported to HPS from another hospital within the same NHS board. All three cases were severely ill due to other underlying conditions and died following their episode of CDI. Other than the shared ribotype, no link has been identified between the cases from the separate hospitals.
This is the first published report of C. difficile PCR ribotype 332 in the UK and worldwide. The predominant PCR ribotypes in Scotland comprise ten common ribotypes including 001, 027 and 106 and the recently emerged ribotype 078 (albeit, the former three types have decreased dramatically in Scotland since 2009). New PCR ribotypes have emerged frequently during the past ten years. Ribotype 332 is considered a sporadic ribotype due to the current low number of isolates.
HPS has alerted clinicians and laboratory staff throughout Scotland.
The identification of a novel ribotype does not require any immediate changes to surveillance or in the antibiotics used to treat CDI. The same infection prevention and control measures apply to CDI caused by PCR ribotype 332 as for cases of CDI caused by any other ribotype.
With only three known detections of this novel ribotype, and it being found (so far) in just two locations, it is too soon to know how big of an impact this new ribotype will have on healthcare.
The CDC provides a good deal of information on C. diff, including this extensive FAQ.
Frequently Asked Questions about Clostridium difficile for Healthcare Providers
Of particular note, unlike viruses and many bacteria, C. diff can be particularly difficult to kill on environmental surfaces or on our hands.
This from the above FAQ.
Because alcohol does not kill Clostridium difficile spores, use of soap and water is more efficacious than alcohol-based hand rubs. However, early experimental data suggest that, even using soap and water, the removal of C. difficile spores is more challenging than the removal or inactivation of other common pathogens.
And like viruses, bacteria like C. diff are constantly reinventing themselves, coming up with new experimental versions to test their biological fitness.
Again from the FAQ.
How has Clostridium difficile (C. difficile) infections (CDI) changed?
Over the past several years nationwide, states have reported increased rates of C. difficile infection, noting more severe disease and an associated increase in mortality. C. diff infection remains a disease mostly associated with healthcare (at least 80%) Patients most at risk remain the elderly, especially those using antibiotics. Although the elderly are still most affected, more disease has been reported in traditionally ‘low risk’ persons such as healthy persons in the community, and peripartum women.
These changes may be largely due to the new emergence of the current epidemic strain of C. difficile, known by its names assigned by various typing schemes as restriction enzyme analysis type BI, North American Pulsed Field type 1 (NAP1), or PCR ribotype 027. BI/NAP1/027 has spread widely after first being found responsible for outbreaks in Pittsburgh (2000), Atlanta (2001-2), and Montreal (2003).
This strain appears more virulent possibly due to its increased production of toxins A and B and its production of an additional toxin known as binary toxin, as well as other factors still under study. In addition to being more virulent, it is more resistant to a commonly-used class of antimicrobials known as the fluoroquinolones.
For more on the challenge of preventing Hospital Acquired Infections you may wish to visit the CDC’s HAI PAGE.
Or revisit some of these earlier blogs on hospital acquired infections.
HPA: Healthcare-Associated Infection (HCAI) Survey
A Barrier To Good Hand Hygiene
Study: Hospital Uniforms And Bacteria
Study: HAIs, Universal Surveillance, & MRSA
And finally, the subject of HAIs is often addressed by Maryn McKenna on her excellent Superbug Blog, and was a major focus of her book SUPERBUG: The Fatal Menace Of MRSA.
Both are highly recommended.
