Newly identified bacterium found to have a broad spectrum of antibiotic resistance

Staphylococcus borealis (S. borealis) was discovered by a research group at UiT The Arctic University of Norway, in Tromsø, in the far north of Norway, beyond the Arctic Circle and found to be a previously unknown type of bacterium. It had previously been misidentified as a Staphylococcus haemolyticus (S. haemolyticus) but 16S rRNA gene sequencing and matrix-assisted laser desorption ionization time-of-flight mass spectrometry analyses revealed marked differences between S. haemolyticus and S. borealis.

Following a whole genome sequence analyses it was described as an entirely new member of the coagulase-negative staphylococci (CoNS) group in 2020. S. borealis lives on human skin and can cause opportunistic infections which can become problematic when the immune system is weakened, particularly among the elderly. It has been found to be intrinsically resistant to several different types of antibiotics and could pose a potentially significant problem for infection control.

To investigate its potential threat to public health researchers collected together for  the study samples of bacteria that had taken at several Norwegian hospitals and kept in freezer storage. Samples went as far back as 2014, with test conducted to see if the new bacterium could be identified from among these old samples. 

Concurrently, samples coming into the UiT lab between 2020 to 2024 were continuously tested. Across the two bands a total of 129 samples, from seven Norwegian hospitals, were collected and analysed.

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The research team discovered that S. borealis exhibits resistance to more than three different classes of antibiotics in one-third of the cases where it was tested.

“We see the most resistance against the antibiotic classes fusidic acid, cephalosporins, penicillins, macrolides, and fluoroquinolones,” explains Dr. Jorunn Pauline Cavanagh, who led the work on bacterial analyses.

Of great concern, the bacterium has shown that it is highly adept at acquiring protective mechanisms from other bacterial species it encounters. This suggests that it has the potential to rapidly develop further levels of resistance when treatment is attempted with currently available antibiotic medicines. 

“[S. borealis] is an opportunist that can cause illness when your immune system is compromised. For example, we have seen that it can form what’s called biofilm around knee prostheses and cause infections that can be difficult to treat,” explained Cavanagh.

Research will now address discovering which diseases can be caused by S. borealis. Initial findings suggest it may cause urinary tract infections, and inflammation where orthopaedic implants are present, such as replacement hips and knees.

“[Elsewhere] we know that it causes mastitis in dromedary camels. We’ve published [its] genetic profile in international databases, which other researchers use to compare their own bacterial findings. So, many more possibilities may emerge,” said Cavanagh.

For further reading please visit: 10.1128/spectrum.01988-24