New antibiotic-resistant bacteria found in Limerick hospital

The new species of bacteria, which is capable of colonising patients in a hospital setting, was identified at University Hospital Limerick.

Researchers at the University of Limerick (UL) have discovered a new species of antibiotic-resistant bacteria in the wastewater system of University Hospital Limerick, one of the country's busiest hospitals.

The new species of bacteria, which is capable of colonising patients in a hospital setting, was also identified from swabs taken from a patient admitted to one of the hospital’s wards.

Laboratory analysis found that the new species is resistant to many commonly used antibiotics, including some that are reserved for resistant bacteria. The patient, who was asymptomatic, did not need treatment with these drugs.

It comes following an extensive study that saw researchers from UL and Queen’s University Belfast, studying the hospital’s wastewater to find a reservoir of bacteria resistant to antibiotics.

Antimicrobial resistance (AMR) is a major challenge that is estimated to be directly responsible for over one million global deaths annually. AMR makes infections harder to treat and increases the risks associated with other medical procedures and treatments.

Study lead and head of UL’s School of Medicine Professor Colum Dunne said the patient had been swabbed as part of a routine safety process put in place with the support of the hospital’s management team prior to the discovery.

“Unusually, the bacteria could not be identified using diagnostic approaches used routinely in hospital labs.

“Using data from our large-scale study of the hospital’s wastewater system and by sequencing the genome of the new isolate, we confirmed two things; that the bacteria are present in the hospital system and the patient was colonised with the bacteria after they were admitted to the hospital,” he said.

The bacterial family, called Pseudocitrobacter, has only recently been classified and the team found that the species is a new addition to that family, having not been reported elsewhere and never isolated from a human sample.

“While an exciting microbiology find, it is important that we stress that the patient remained colonised only, asymptomatic, and did not merit antimicrobial treatment for this species,” he said.

Mr Dunne said that it is “very likely” that the discovery of new bacterial species will happen more frequently as hospitals across the world are environments where there is “heavy use” of pharmaceutical products, such as antibiotics, and in that type of ecosystem, mutations occur frequently.

“In our hospital group, there is recognition of these risks. Our work has been enabled by a forward-looking approach to infection prevention and the facilitation of research by the hospital’s management. 

"Such support is an indicator of a healthcare system focused on best practice for proactive and solution-oriented research that can make a difference," he said.

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Mr Dunne said it is likely that the analysis performed will become more widely available, less expensive, and allow identification of infectious agents more rapidly, “possibly even through bedside or point of care testing as technology improves.” 

“This is an example of innovation with real impact for society. University-based researchers bring expertise and access to sophisticated molecular equipment that, together with the clinical knowledge of hospital-based doctors and surveillance scientists, can help to ensure patient safety is protected,” he said.