Researchers believe new findings about genetic changes in C. difficile are a sign that it is becoming more difficult to eradicate

Hospital infection control teams, microbiologists, and clinical laboratory professionals soon may be battling a strain of Clostridium difficile (C. difficile) that is even more resistant to disinfectants and other forms of infection control.

That’s the opinion of research scientists at the Wellcome Sanger Institute (WSI) and the London School of Hygiene and Tropical Medicine (LSHTM) in the United Kingdom who discovered the “genetic changes” in C. difficile. Their genomics study, published in Nature Genetics, shows that the battle against super-bugs could be heating up.

A WSI news release states the researchers “identified genetic changes in the newly-emerging species that allow it to thrive on the Western sugar-rich diet, evade common hospital disinfectants, and spread easily.”

Microbiologists and infectious disease doctors know full well that this means the battle to control HAIs is far from won.

C. difficile is currently forming a new species with one group specialized to spread in hospital environments. This emerging species has existed for thousands of years, but this is the first time anyone has studied C. difficile genomics in this way to identify it. This particular [bacterium] was primed to take advantage of modern healthcare practices and human diets,” said Nitin Kumar, PhD (above), in the news release. (Photo copyright: Wellcome Sanger Institute.) 

Genomic Study Finds New Species of Bacteria Thrive in Western Hospitals

In the published paper, Nitin Kumar, PhD, Senior Bioinformatician at the Wellcome Sanger Institute and Joint First Author of the study, described a need to better understand the formation of the new bacterial species. To do so, the researchers first collected and cultured 906 strains of C. difficile from humans, animals, and the environment. Next, they sequenced each DNA strain. Then, they compared and analyzed all genomes.

The researchers found that “about 70% of the strain collected specifically from hospital patients shared many notable characteristics,” the New York Post (NYPost) reported.

Hospital medical laboratory leaders will be intrigued by the researchers’ conclusion that C. difficile is dividing into two separate species. The new type—dubbed C. difficile clade A—seems to be targeting sugar-laden foods common in Western diets and easily spreads in hospital environments, the study notes. 

“It’s not uncommon for bacteria to evolve, but this time we actually see what factors are responsible for the evolution,” Kumar told Live Science.

New C. Difficile Loves Sugar, Spreads

Researchers found changes in the DNA and ability of the C. difficile clade A to metabolize simple sugars. Common hospital fare, such as “the pudding cups and instant mashed potatoes that define hospital dining are prime targets for these strains”, the NYPost explained.

Indeed, C. difficile clade A does have a sweet tooth. It was associated with infection in mice that were put on a sugary “Western” diet, according to the Daily Mail, which reported the researchers found that “tougher” spores enabled the bacteria to fight disinfectants and were, therefore, likely to spread in healthcare environments and among patients.

“The new C. difficile produces spores that are more resistant and have increased sporulation and host colonization capacity when glucose or fructose is available for metabolism. Thus, we report the formation of an emerging C. difficile species, selected for metabolizing simple dietary sugars and producing high levels or resistant spores, that is adapted for healthcare-mediated transmission,” the researchers wrote in Nature Genetics.

Bacteria Pose Risk to Patients

The findings about the new strains of C. difficile bacteria now taking hold in provider settings are important because hospitalized patients are among those likely to develop life-threatening diarrhea due to infection. In particular, people being treated with antibiotics are vulnerable to hospital-acquired infections, because the drugs eliminate normal gut bacteria that control the spread of C. difficile bacteria, the researchers explained.

According to the Centers for Disease Control and Prevention (CDC), C. difficile causes about a half-million infections in patients annually and 15,000 of those infections lead to deaths in the US each year.

New Hospital Foods and Disinfectants Needed

The WSI/LSHTM study suggests hospital representatives should serve low-sugar diets to patients and purchase stronger disinfectants. 

“We show that strains of C. difficile bacteria have continued to evolve in response to modern diets and healthcare systems and reveal that focusing on diet and looking for new disinfectants could help in the fight against this bacteria,” said Trevor Lawley, PhD, Senior Author and Group Leader of the Lawley Lab at the Wellcome Sanger Institute, in the news release.

Microbiologists, infectious disease physicians, and their associates in nutrition and environmental services can help by understanding and watching development of the new C. difficile species and offering possible therapies and approaches toward prevention.

Meanwhile, clinical laboratories and microbiology labs will want to keep up with research into these new forms of C. difficile, so that they can identify the strains of this bacteria that are more resistant to disinfectants and other infection control methods.  

—Donna Marie Pocius

Related Information:

Adaptation of Host Transmission Cycle During Clostridium Difficile Speciation

Diarrhea-causing Bacteria Adapted to Spread in Hospitals

Sugary Western Diets Fuel Newly Evolving Superbug

New Carb-Loving Superbug is Primed to Target Hospital Food

Superbug C Difficile Evolving to Spread in Hospitals and Feeds on the Sugar-Rich Western Diet

CDC: Healthcare-Associated Infections-C. Difficile