GHA lab team highlights growing threat of antibiotic resistance

The team in the GHA’s microbiology department is highlighting the growing challenge of antibiotic resistance and calling for greater public awareness during World Antimicrobial Resistance Awareness Week (WAAW).

Antimicrobial resistance (AMR) occurs when bacteria, viruses, fungi and parasites no longer respond to antimicrobial agents. As a result, antibiotics and other treatments become ineffective and infections are harder or impossible to treat, increasing the risk of disease spread, severe illness and death, according to the World Health Organisation.

The theme for WAAW 2025 is “Act Now: Protect Our Present, Secure Our Future.” The weeklong global campaign aims to raise awareness and increase understanding of AMR, and to promote coordinated action to tackle the emergence and spread of drug-resistant pathogens.

During a recent briefing at St Bernard’s Hospital, Consultant Medical Microbiologist Dr Nick Cortes and the team at the Microbiology Lab explained the critical work carried out each day to identify infectious agents and guide appropriate treatment.

Biomedical Scientist Nicole Santos described the meticulous process: “We study microbes.”

“We do different bacterias, parasites, fungi, mostly bacterias, but we have different types of plates with selective agars.”

“And depending on what organism is present in a sample, it will grow differently depending on the different plates.”

She explained that assistants receive the samples and culture them on the first day. They are incubated overnight and checked the following morning to determine whether there is growth.

If there is growth, the team assesses whether it is significant.

“We would identify the organisms growing on the plate, and if they are significant, we will then do further tests to check the sensitivity is antibiotics,” she said.

“A lot of times, the doctors will tell us, ‘Oh, we put them on this antibiotics’, and we'll just check that, along with a panel that we have already preset to make sure that they're being treated correctly, and if not, then the doctors should change their treatment.”

The team studies microbes in a range of samples including urine, skin, stools and blood.

They noted that while some infections, such as those caused by E. coli, remain common, the emergence of so-called “superbugs” like MRSA and multi-resistant strains of E. coli is complicating treatment guidelines.

“Especially for urine tract infections, E coli is a very common so we identify quite a lot of those.
And then, unfortunately, if they're not treated in a timely manner, some people can't go on to develop urosepsis, which is infection in the blood caused by a infection in the urinary tract,” she said.

“Normally, when they send a pair of a urine sample and a blood culture, we'll see it's normally the same organism causing the infection in both.”

When the team encounters a “superbug”, the response depends on where the patient is being treated.

“It depends on whether the patient is in hospital or outside, and if they're in hospital, we have certain infection control measures we need to put into place so that they don't spread to other patients,” she said.

The most common “superbugs” are MRSA and multi-resistant strains of E. coli, and the team is seeing these more often than they would like, said Dr Cortes.

“In terms of making treatment for patients a lot more complicated, because you have less or fewer antibiotic options, and some of the options are only intravenous, which obviously has an implication for that patient having to come into hospital rather than being able to be treated in the community. So that's why we want to raise awareness of the real challenge that antimicrobial resistance poses,” he added.

Lab data show that Gibraltar’s rates of antibiotic resistance, influenced by frequent cross-border movement, generally mirror those found in Spain, though for some bacteria rates are closer to UK levels.

The team tracks these patterns and uses the data to inform the GHA’s antibiotic prescribing guidelines, which are available to doctors via an app.

Testing methods range from classic Petri dishes with antibiotic-impregnated disks, which visually show zones where bacteria fail to grow, to advanced graded strips that measure precise sensitivity levels. Results are reported back to doctors in real time and used to update guidelines annually.

“So what we normally do is we test a variety of antibiotics, but we don't tell the doctor about all of the sensitivities, and we keep them hidden, and we normally release the first line of antibiotics because you don't want to release the stronger ones, because you don't want the bacteria to become resistant. So you start off with the first line if they're sensitive to make sure they don’t become resistant in the future,” said Ms Santos.

Dr Cortes described this as their “Stewardship of antibiotics” and stressed that if the first line does not work, further options are released in sequence.

“What we don't want to do is give doctors too many options, sort of burn our bridges by giving out some of the ones that we're trying to keep a little bit in reserve, because we may need them in the future,” he said.

The experts urged both the public and healthcare professionals to follow guidance and avoid unnecessary antibiotic use, with Dr Cortes noting that antibiotic resistance is a global problem but also a very local one.

He also noted that “without this team here Gibraltar would be in a very difficult position. The lab here are the eyes and ears for antibiotic resistance, for the territory, that's really important.”