Hong Kong scientists discover newly emerged hyper-resistant superbug

HONG KONG -- A newly emerged superbug that may cause untreatable infections on relatively healthy people was discovered by researchers from the Hong Kong Polytechnic University which made the results public on Thursday.

The superbug, known as ST11 carbapenem-resistant hypervirulent Klebsiella pneumoniae (ST11 CR-HvKP), is high transmissible, hyper-resistant and hypervirulent, according to findings made by the Partner State Key Laboratory of Chirosciences at the university's Department of Applied Biology and Chemical Technology (ABCT).

Chen Sheng, a professor of the ABCT department, collaborated with the Chinese mainland researchers and conducted an investigation into a fatal outbreak of pneumonia in the Second Affiliated Hospital of Zhejiang University in February 2016.

The study involved five patients who underwent surgical operation for multiple-trauma. All of them were later infected in the intensive care unit (ICU) and developed severe pneumonia, and eventually died of septicaemia and multiple organ failure.

The causative agent of these five patients was found to be a carbapenem-resistant Klebsiella pneumoniae (CRKP) strain, a type of previously-defined superbug, belonging to ST11 type of CRKP, the most prevalent and transmissible CRKP strains in Asia.

The ST11 CR-HvKP strains do not only infect lungs and cause pneumonia, but also invade the bloodstream and other internal organs. Due to its hypervirulence and phenotypic resistance to commonly used antibiotics, ST11 CR-HvKP strains may cause untreatable and fatal infections in relatively healthy individuals with normal immunity.

ST11 CR-HvKP strains possess a mucoid outer layer, which, Chen said, enables them to stick to various materials, such as the surface of medical devices, tubing and other surfaces in the ICU.

The transmission route, however, is not clear yet. But the study data suggested that medical equipment might be transmitting these new superbug strains, Chen said, adding that human-to-human transmission may also be possible, mainly in hospital settings.

ST11 CR-HvKP can easily be detectable by the Polymerase chain reaction method, targeting specific resistance and virulence genes.

It is suggested that improved infection prevention and control policy in hospital seems to be effective to control further transmission of this superbug in the ICU.

Prevalence of ST11 CR-HvKP strains in Hong Kong is currently unknown, but analysis of Klebsiella pneumoniae genome sequence has shown that dissemination of CR-HvKP has occurred worldwide, according to the researchers.

The study is recently published in the prestigious academic journal The Lancet Infectious Diseases.