In particularly unwelcome news from China, researchers report they have isolated a strain of Klebsiella pneumoniae that is both hypervirulent and highly drug-resistant. A worse combination is difficult to imagine. Usually, hypervirulent K. pneumoniae remains susceptible to drugs, but acquiring resistance apparently through genetic transfer in nature means this is a bug that could possibly infect heathy people in the community, let alone frail hospital patients.

The pathogen was discovered during an investigation of a fatal outbreak of ventilator-associated pneumonia in an ICU at the Second Affiliated Hospital of Zhejiang University in Hangzhou. The researchers collected 21 carbapenem-resistant K. pneumoniae strains from five patients, all of whom died. As infection preventionists are well aware, carbapenem is a last resort drug and its use typically indicates nothing else has worked.

All five patients — aged 53 to 73 — had undergone surgery for multiple trauma and placed on mechanical ventilation.

“They all had severe pneumonia, carbapenem-resistant K. pneumoniae infections, and poor responses to antibiotic treatment, and died due to severe lung infection, multiorgan failure, or septic shock,” the researchers reported.1 “All five representative carbapenem-resistant K. pneumoniae strains belonged to the ST11 type, which is the most prevalent carbapenem-resistant K. pneumoniae type in China, and originated from the same clone. The ST11 carbapenem-resistant hypervirulent K. pneumoniae strains pose a substantial threat to human health because they are simultaneously hypervirulent, multidrug-resistant, and highly transmissible.”

It seems virtually inevitable that we will see this pathogen in the United States. Last year, a female patient in an acute care hospital in Reno, NV, died of carbapenem-resistant Enterobacteriaceae (CRE) that was resistant to 26 antibiotics.2 The pathogen was K. pneumoniae that was isolated from a wound specimen. Of note, the patient had recently been hospitalized in India, and the specific enzyme conferring pan resistance was first discovered in that country: New Delhi metallo-beta-lactamase-1 (NDM-1).

In addition, medical researchers performing a lab experiment previously combined a K. pneumoniae carbapenemase (KPC) strain now common in much of the U.S. with a highly virulent isolate from Asia, conferring the multidrug resistance of the former and the killing power of the latter into a new microorganism similar to one detected in China. Researcher Tom Chiang, MD, an assistant professor at Rutgers New Jersey Medical School who conducted the experiment, essentially predicted the China finding would happen in a previous interview with Hospital Infection Control & Prevention. (For more information, see the February 2014 issue of HIC.)

“Our study was important to show that it is possible for the virulent strains to obtain KPCs and we’re just beginning to see the tip of the iceberg on carbapenem resistant — possibly pan resistant — strains of K. pneumoniae emerge,” Chiang says. “It will probably first disseminate in Asia, as the virulent strains are endemic there. If it disseminates here, the consequences will be catastrophic for the healthcare system. K. pneumoniae is the second-most prevalent gram-negative bacteria in our hospital and our affiliated hospitals, surpassing Pseudomonas aeruginosa several years ago and second only to E. coli now.”

REFERENCES

  1. Gu D, Ning D, Zheng, Z, et al. A fatal outbreak of ST11 carbapenem-resistant hypervirulent Klebsiella pneumoniae in a Chinese hospital: a molecular epidemiological study. Lancet Infect Dis August 29, 2017: DOI: http://dx.doi.org/10.1016/S1473-3099(17)30489-9.
  2. CDC. Notes from the Field: Pan-Resistant New Delhi Metallo-Beta-Lactamase-Producing Klebsiella pneumoniae — Washoe County, Nevada, 2016. MMWR 2017;66(1):33.