University in Hong Kong discovers newly emerged superbug

Researchers at The Hong Kong Polytechnic University, or PolyU, have discovered a newly-emerged superbug that could pose a significant threat to human health.

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The team investigated a fatal outbreak of pneumonia in February 2016 in five patients in the Second Affiliated Hospital of Zhejiang University in China.
The five patients all underwent surgical operations for multiple trauma and were later infected in the intensive care unit and developed severe pneumonia, dying from septicaemia and multiple organ failure.

Researchers identified that the patients all had Klebsiella pneumoniae, or CRKP, strain, which is a type of previously-defined superbug. The CRKP strains are hyper-virulent and are part of the ST11 type of CRKP, the most common and contagious of all CRKP strains in Asia.

The combination of hyper-resistance, hyper-virulence and high transmissibility makes it a real superbug known as ST11 CR-HvKP, or ST11 carbapenem-resistant hyper-virulent K. pneumoniae.

The prevalence of ST11 CR-HvKP strains is unknown in Hong Kong, however, two other studies have shown the mortality rate from K. pneumoniae-mediated bloodstream infections was 20 percent and 32 percent.

ST11 K. pneumoniae grow in the gastrointestinal tract in humans and animals and can lead to pneumonia in clinical settings. The strains become resistant to carbapenem antibiotics leading to untreatable or hard-to-treat infections. The superbug strains can evolve further into ST11 CR-HvKP by acquisition of hyper-virulence plasmids.

ST11 CR-HvKP strains not only infect the lungs causing pneumonia, but can get into the bloodstream and infect other internal organs. This makes the superbug able to infect even healthy individuals with normal immune systems.

By Amy Wallace