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Hypervirulent Carbapenem-resistant Klebsiella Pneumoniae Emerges

By Will Boggs MD

September 08, 2017

NEW YORK (Reuters Health) - An ST11 carbapenem-resistant hypervirulent Klebsiella pneumoniae caused a fatal outbreak in a Chinese hospital and could pose a threat elsewhere, researchers report.


“This new type of superbug possesses three new features simultaneously, including high transmissibility, high resistance to antibiotics, and high virulence,” Dr. Sheng Chen from The Hong Kong Polytechnic University told Reuters Health by email.

香港理工大学的Sheng Chen博士在邮件中对路透社说到:“这种新型的超级细菌同时具有三种新的特点,包括高度可传播性,对抗生素的高度耐药性,以及高毒力。”

Hypervirulent K. pneumoniae can cause life-threatening, community-acquired infections, but most hypervirulent strains have remained antibiotic-sensitive. The ST11 strain of K. pneumoniae is carbapenem-resistant but has not previously been associated with hypervirulence.


Dr. Chen and colleagues describe the investigation of an outbreak of ventilator-associated pneumonia due to hypervirulent ST11 K. pneumoniae in 5 patients in their August 29 Lancet Infectious Diseases online report.

在Lancet Infectious Diseases杂志8月29日在线发表的报告中,Chen博士及其同事描述了他们对于ST11耐碳青霉烯高毒力肺炎克雷白杆菌引起的5名患者呼吸机相关肺炎的暴发流行的研究结果。

Carbapenem-resistant K. pneumoniae was consistently isolated from different specimens in all patients before they died of severe lung infection, multiorgan failure, or septic shock after periods ranging from 10 days to 4 months.


The isolated strains had almost identical antibacterial susceptibility profiles and belonged to ST11, but these strains caused much more severe pneumonia and higher mortality than that associated with other ST11 carbapenem-resistant infections.


These strains also appeared to be more virulent in a human neutrophil assay than 2 classic ST11 strains and 2 K1 hypervirulent K. pneumoniae strains.


Genes unique to these hypervirulent ST11 strains aligned well with a virulence plasmid recovered from K. pneumoniae strain CG43 and distinguished these carbapenem-resistant strains from the classic ST11 carbapenem-resistant strains.


Retrospective screening of 387 clinical ST11 carbapenem-resistant K. pneumoniae strains collected from across China identified this virulence plasmid in 11 (3%) of the strains. Five of the 11 patients infected with these strains died; the other 6 were discharged with critical illnesses.


“Due to acquisition of a virulence plasmid by classic ST11 carbapenem-resistant K. pneumoniae strains, these new strains are simultaneously hypervirulent, multidrug-resistant, and transmissible, and should therefore be regarded as a real superbug that could pose a serious threat to public health,” the researchers note.


“Currently there are no antibiotics available to treat the infections caused by this superbug in China,” Dr. Chen said. “We have tried some new Infection Prevention and Control (IPC) policies, which seem to be effective in stopping the transmission of this superbug in ICUs in hospital.”


“This newly emerged superbug is mistakenly considered as normal carbapenem-resistant Klebsiella pneumoniae (CRKP),” he said. “However, this superbug has much higher morbidity and mortality than normal CRKP strains. We would like physicians to be alert (to) this new type of CRKP and differentiate (it) from normal CRKP, since new treatment will be needed for this hypervirulent and hyperresistant superbug. We also urge scientists and physician to do more research to find the best treatment for this type of superbug.”


Dr. Liang Chen from New Jersey Medical School, Rutgers University, who wrote an editorial related to this report, told Reuters Health by email, “Needless to say, we are facing a plasmid-mediated crisis. This plasmid-mediated threat is of exceptional public health concern, as the resistance and virulence genes can be easily spread between bacteria and humans.”

来自Rutgers大学新泽西医学院的Liang Chen医生为这遍报告写了述评。他在电子邮件中对路透社健康频道说到:“毋庸置疑,我们面临着质粒介导的危机。这一质粒介导的威胁对公共健康造成重大影响,因为耐药基因和毒力基因很容易在细菌和人类之间传播。”

“We have seen the spread of promiscuous resistance (e.g., KPC, NDM and MCR-1) plasmids into different bacterial species in animals and humans,” he explained. “Historically, the virulence plasmid was usually restricted in certain hypervirulent strain backgrounds. The Lancet Infectious Diseases study represents the first report that the virulence plasmid emerged into a classical multidrug-resistant strain. It would be disturbing to see if the virulence plasmids further spread into other K. pneumoniae strains, such as the global epidemic ST258 strains, which account for >70% of carbapenem-resistant Enterobacteriaceae isolates in the U.S.”

“我们曾经观察到混杂耐药 (如 KPC, NDM 和 MCR-1) 质粒传播到动物和人类的不同细菌中,”他解释到。“从历史上看,毒力质粒通常限于某些高毒力菌株。Lancet Infectious Diseases发表的研究第一次报告了毒力质粒可以出现在经典的多重耐药菌株中。如果发现这一毒力质粒进一步播散到其他肺炎克雷白杆菌菌株中将令人不安,正如ST258菌株造成的全球流行一样,后者在美国的耐碳青霉烯肠杆菌科细菌中占70%以上。”

“Doctors should be alert to the emergence of the hypervirulent carbapenem-resistant strains in their own hospitals,” Dr. L. Chen concluded. “Enhanced detection and reporting systems and an IPC plan should be developed, especially for hospitals located in high-risk regions.”

“医生应当警惕这种高毒力耐碳青霉烯菌株在自己医院中的出现,”Chen L医生总结到。“应当改进检测及报告系统,并制订感染预防控制计划,尤其对于处于高危地区的医院而言。”

Dr. Hui Wang from Peking University People’s Hospital, Beijing, China, who has studied outbreaks associated with other ST11 strains, told Reuters Health by email, “The newly emerged carbapenem-resistant ST11 hypervirulent K. pneumoniae might cause a serious threat to public health worldwide, due to their simultaneous hypervirulence, multidrug resistance, and high transmissibility.”

北京大学人民医院的Hui Wang医生研究过其他ST11株的暴发流行。她在电子邮件中对路透社健康频道说,“这种新出现的耐碳青霉烯ST11高毒力肺炎克雷白杆菌同时具有高毒力、多重耐药性及高传播性,可能对全球的公共健康造成严重威胁。”

“Importantly, such strains have disseminated among various regions and in China and might have emerged in Western countries, because of the genetic similarity between ST11 and ST258 of K. pneumoniae,” she said. “Implementation of control measures are needed to prevent strains from further disseminating in hospital settings and the community.”


SOURCES: http://bit.ly/2wHUBn5 and http://bit.ly/2eFyJR7

Lancet Infect Dis 2017.


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