An international team of scientists investigating transmission of deadly, drug-resistant bacteria that rivals MRSA has found that while the bugs are found in livestock, pets and the wider environment, they are rarely transmitted to humans through this route.
The researchers, led by Professor Ed Vail of the Milner Center for Evolution at the University of Bath, investigated the spread of Klebsiella A family of bacterial species that live harmlessly in the intestines, but can be dangerous if they spread to other parts of the body.
Klebsiella pneumoniae It is the most well-known species in this family, which can cause pneumonia, meningitis, urinary tract infections, and bloodstream infections.
These bacteria are now extremely resistant to antibiotics, with some strains even resistant to carbapenems, one of the so-called “last resort” class of antibiotics that are only used when there is no other antibiotic treatment.
Klebsiella It has overtaken MRSA as a health problem in the UK, with rates rising steadily. The World Health Organization has recognized the bacterium as a healthcare-associated pathogen of critical priority.
In addition to being present in hospitals, the microbe has previously been detected in the environment, including livestock and wastewater, but until now it was not clear whether the bacteria transmitted between clinical and non-clinical environments.
In the largest study ever conducted, the team collected 6,548 samples over 15 months from various sites in and around the Italian city of Pavia, where this pathogen is a major problem in hospitals, and analyzed them using whole-genome sequencing techniques to detect them. and specify any Klebsiella The bacteria are present.
The team examined patients in hospitals and healthy “carriers” in the community, taking samples from farms, ponds, pets and even houseflies and other insects to discover where the bacteria might be.
Hence, they found 3482 isolates, including 15 different species of Klebsiellawith half of the positive samples contained K. pneumoniae.
When the team genetically sequenced the bacteria to find which strains were present, they found that there was very little overlap between those hospital bugs and those in the environment.
Professor Ed Vail, who supervised the study, said:Klebsiella Infections are becoming increasingly resistant to antibiotics, so while you used to be able to treat most UTIs easily, it is now more common for patients to get infections that keep coming back and causing problems.
“Klebsiella It can also cause pneumonia, which kills about half of patients. This bacteria is a bigger problem in the UK than MRSA.
“Our researchers wanted to see if resistant bacteria were now circulating in pets, farms, livestock, plants and water, and so we wanted to investigate where Klebsiella It is found and how it spreads is monitored, to inform on how best to prevent and control disease outbreaks.
“We found that it was ubiquitous, but we were surprised that the strains in the hospital were different from those in the environment, which indicates that there is very little transmission between habitats: humans always catch this from other humans.
“This confirms that the best way to control infections with these bacteria is still strict hygiene in hospitals, and that there is less chance that outbreaks could be caused by contact with animals or the environment than previously feared, at least in a resource-rich country like Italy.”
Dr Harry Thorpe, from the University of Oslo (Norway) and first author of the paper, said: “The fear was that farmers might pass on these bacteria from their livestock or soil, and we could get contaminated salad or get sick if we were swimming in infected lakes.
“Our research provided no evidence for this, however, we did find Klebsiella resistance in domestic animals, such as cats and dogs. Veterinarians and owners should be aware of this, as these animals can present a risk for spreading the bacteria.”
The project, called SpARK, was led by the Bath consortium, but included researchers from the UK (the Wellcome Sanger Institute, the universities of Bristol and Glasgow), Norway, France, Finland and Italy. The work was funded by the Joint Programming Initiative on Antimicrobial Resistance (JPI-AMR), the Medical Research Council, and is published in Nature Microbiology.
Professor Phil said: “This is the largest and most systematic study ever conducted at the same time in a single geographical location.
“We looked at transmission of strains, but antibiotic resistance can be conferred on other strains very easily when they exchange and capture circular pieces of DNA called plasmids.
“Next we want to track how plasmids are transmitted between strains, using a technique called long read sequencing.”
The team was recently awarded a network grant from JPIAMR to do this, which builds on the GW4 research community and was supported by the GW4 AMR Alliance.