The World Health Organization (WHO) has called for vigilance as an antibiotic-resistant superbug spreads.  

The hypervirulent Klebsiella pneumoniae sequence type 23 (hyKp ST23) has been identified in at least one country across all six WHO health regions, including Australia. 

The bacteria is particularly concerning as it shows resistance to last-line antibiotics, such as carbapenems, which are typically used as a final treatment option for severe infections. 

WHO's assessment of the global risk posed by this superbug is currently classified as ‘moderate’. 

However, this classification is largely due to significant challenges in monitoring the superbug's spread, limited data on infection rates, and gaps in understanding its full impact on hospitalisation and overall disease burden. 

The organisation is urging countries to work with laboratories on detecting and identifying hyKp ST23 more reliably and at an earlier stage.

It says the emergence of hyKp ST23 requires alternative antimicrobial treatments, which may not be readily available in many regions. 

“Countries should reinforce the central role of national reference laboratories in molecular testing and in detection and analyses of relevant virulence genes,” the WHO advises, stressing the need for improved surveillance and diagnostic tools.

In January 2024, the Global Antimicrobial Resistance and Surveillance System on Emerging Antimicrobial Resistance Reporting (GLASS-EAR) began collecting information from 124 countries to assess the global situation of hyKp ST23. 

In total, 16 countries, including Australia, reported the presence of this superbug. 

Additionally, 12 countries confirmed the existence of the specific strain ST23-K1, a variant known for its high virulence and resistance.

The WHO has also highlighted the capacity to spread in both community and hospital settings. The organisation emphasised that the bacteria’s resistance to carbapenems limits treatment options, which raises concerns about potential outbreaks.

The emergence is part of a broader pattern of antibiotic resistance seen in Klebsiella pneumoniae strains globally. 

Historically, these bacteria have been opportunistic pathogens, mainly affecting hospitalised or immunocompromised individuals. However, the hyKp ST23 strain marks a worrying shift, as it is capable of causing severe infections in healthy individuals as well.

The WHO is calling for authorities to focus on infection prevention and control measures within healthcare facilities. 

Countries are encouraged to implement enhanced precautions to manage suspected or confirmed cases of hyKp ST23, especially in settings with limited resources and diagnostic capabilities. 

The WHO also advocates for the development of a consensus definition for hyKp to aid in its identification and management.

The organisation says that given the limited treatment options and the potential for widespread transmission, nations should remain vigilant and continue reporting new cases through established global and regional channels. 

“Detection of the emergence of multi-resistant or extensively resistant pathogens requires established resistance laboratory surveillance systems as well as effective infection prevention and control programs in health-care facilities,” the WHO stated, calling for a coordinated global response to this emerging threat.

More details are accessible here.