The World Health Organisation has issued a warning about a superbug, hypervirulent Klebsiella pneumoniae sequence type 23 (hyKp ST23), which has been reported in at least one country in all six WHO Regions – including Australia.
The WHO said that new K. pneumoniae strains have been identified with increasing frequency, are often resistant to last-line (carbapenem) antibiotics, and can cause severe infections, even in healthy individuals.
They are considered hypervirulent compared to classical variants because of their increased tendency to produce invasive infections.
HvKp has also been implicated in primary extrahepatic infections, including bacteraemia, pneumonia, and soft tissue infections, and because the strain is carried in the gastrointestinal tract, it is more easily spread within community and health care settings.
Symptoms of hvKp are nonspecific and may include fever, chills, abdominal pain, nausea, and vomiting, but also depend on the location of the primary and metastatic infection. For example, it has been linked with pyogenic liver abscesses which can metastasise to distant sites, such as the eyes, lungs, and central nervous system (CNS).
The WHO has assessed the current risk as moderate due to the challenges with surveillance, the lack of information on laboratory testing rates and the scale of community transmission, as well as the gap in the available data on infections, hospitalisations, and overall burden of disease.
“Identification of hvKp is a challenging given that it is determined by available laboratory capacity to perform genomic sequencing tests or analysis of specific markers that may indicate hypervirulence, so the prevalence of hvKp-associated infections may be underestimated,” the WHO said.
“The emergence of these isolates with resistance to last-line antibiotics like carbapenems necessitates the administration of alternative antimicrobial treatment, which may not be available in many contexts.
“Similarly, the prevention and control of carbapenemase-carrying hvKp poses significant challenges as it has not been possible to establish the extent of its dissemination in the countries of the region and information on this subject is currently limited.”
The WHO noted that significantly more research was needed to develop diagnostic tools for countries with limited laboratory capacity – an area of research where Australia has been leading the way.