Bugs without borders: Researchers track the emergence and global spread of healthcare associated Clostridium difficile

December 9, 2012, Wellcome Trust Sanger Institute

Researchers show that the global epidemic of Clostridium difficile 027/NAP1/BI in the early to mid-2000s was caused by the spread of two different but highly related strains of the bacterium rather than one as was previously thought. The spread and persistence of both epidemics were driven by the acquisition of resistance to a frontline antibiotic.

Unlike many other healthcare-associated bacteria, C. difficile produces highly resistant and infectious spores. These spores can promote the transmission of C. difficile and potentially facilitates its spread over greater geographical distances, even across continents.

This study highlights the ease and rapidity with which the hospital , C. difficile, can spread throughout the world, emphasising the of the global healthcare system.

"Between 2002 and 2006, we saw highly publicised outbreaks of C. difficile in hospitals across the UK, USA, Canada and Europe," says Dr Miao He, first author from the Wellcome Trust Sanger Institute. "We used advanced DNA sequencing to determine the of this epidemic and the subsequent pattern of global spread.

"We found that this outbreak came from two separate epidemic strains or lineages of C. difficile, FQR1 and FQR2, both emerging from North America over a very short period and rapidly spread between hospitals around the world."

The team used the genetic history to map both epidemic strains of C. difficile using a global collection of samples from hospital patients between 1985 and 2010. They demonstrated that the two C. difficile strains acquired resistance to this antibiotic, fluoroquinolone, separately, a key that may have instigated the epidemics in the early 2000s.

"Up until the early 2000s, fluoroquinolone was an effective treatment for C. difficile infection," says Professor Brendan Wren, author from the London School of Hygiene and Tropical Medicine. "We've seen that since these strains acquired resistance to this frontline antibiotic, not only is it now virtually useless against this organism, but resistance seems to have been a major factor in the continued evolution and persistence of these strains in hospitals and clinical settings."

The team found the first outbreak strain of C. difficile, FQR1 originated in the USA and spread across the country. They also saw sporadic cases of this strain of C. difficile in Switzerland and South Korea. They found that the second strain of C. difficile, FQR2, originated in Canada and spread rapidly over a much wider area, spreading throughout North America, Australia and Europe.

The team showed that the spread of C. difficile into the UK was frequently caused by long-range geographical transmission event and then spread extensively within the UK. They confirmed separate transmission events to Exeter, Ayrshire and Birmingham from North America and a transmission event from continental Europe to Maidstone. These events triggered large-scale C. difficile outbreaks in many hospitals across the UK in the mid-2000s.

"We have exposed the ease and rapidity with which these fluoroquinolone-resistant C. difficile have transmitted across the world," says Dr Trevor Lawley, lead author from the Wellcome Trust Sanger Institute. "Our research highlights how the global healthcare system is interconnected and how we all need to work together when an outbreak such as this occurs.

"Our study heralds a new era of forensic microbiology for the transmission tracking of this major global pathogen and will now help us understand at the genetic level how and why this pathogen has become so aggressive and transmissible worldwide. This research will act as a database for clinical researchers to track the genomic changes in C. difficile outbreaks."

Explore further: Outbreak C. difficile strain common in Chicago hospitals, investigation finds

More information: Nature Genetics doi:10.1038/ng.2478

Related Stories

Outbreak C. difficile strain common in Chicago hospitals, investigation finds

August 11, 2011
An outbreak strain of Clostridium difficile, a bacterium that causes diarrhea and sometimes life-threatening inflammation of the colon, is common in Chicago-area acute care hospitals, an investigation published in the September ...

C. difficile lengthens hospital stays by 6 days

December 5, 2011
A new study published in the CMAJ (Canadian Medical Association Journal) reports that hospital-acquired Clostridium difficile infection increases length of stay in hospital by an average of six days.

Transmission of Clostridium difficile in hospitals may not be through contact with infected patients

February 7, 2012
Contrary to current convention by which infection with the organism Clostridium difficile is regarded as an infection that is acquired by contact with symptomatic patients known to be infected with C. difficile, these may ...

Reporting of hospital infection rates and burden of C. difficile

July 17, 2012
A new study published today in PLoS Medicine re-evaluates the role of public reporting of hospital-acquired infection data.

Recommended for you

Peers' genes may help friends stay in school, new study finds

January 18, 2018
While there's scientific evidence to suggest that your genes have something to do with how far you'll go in school, new research by a team from Stanford and elsewhere says the DNA of your classmates also plays a role.

Two new breast cancer genes emerge from Lynch syndrome gene study

January 18, 2018
Researchers at Columbia University Irving Medical Center and NewYork-Presbyterian have identified two new breast cancer genes. Having one of the genes—MSH6 and PMS2—approximately doubles a woman's risk of developing breast ...

Can mice really mirror humans when it comes to cancer?

January 18, 2018
A new Michigan State University study is helping to answer a pressing question among scientists of just how close mice are to people when it comes to researching cancer.

A centuries-old math equation used to solve a modern-day genetics challenge

January 18, 2018
Researchers developed a new mathematical tool to validate and improve methods used by medical professionals to interpret results from clinical genetic tests. The work was published this month in Genetics in Medicine.

Epigenetics study helps focus search for autism risk factors

January 16, 2018
Scientists have long tried to pin down the causes of autism spectrum disorder. Recent studies have expanded the search for genetic links from identifying genes toward epigenetics, the study of factors that control gene expression ...

Group recreates DNA of man who died in 1827 despite having no body to work with

January 16, 2018
An international team of researchers led by a group with deCODE Genetics, a biopharmaceutical company in Iceland, has partly recreated the DNA of a man who died in 1827, despite having no body to take tissue samples from. ...

0 comments

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.