Detection of Hypervirulent Klebsiella pneumoniae Strains in New York City

A team of researchers conducted surveillance at a New York City hospital to assess the prevalence K pneumoniae.

Multiple strains of a hypervirulent variant of Klebsiella pneumoniae are emerging in New York City, according to surveillance results published in Clinical Microbiology and Infection.

The emerging K pneumoniae hypervirulent variant identified in Western countries is already a predominant cause of community-acquired pyogenic liver abscess in Asia. Investigators were alerted to its presence in New York by 2 cases, both involving elderly Hispanic men who presented with recurrent fever, bacteremia, epigastric pain, and liver abscesses/phlegmon. In response, surveillance of K pneumoniae blood, body fluid, and wound isolates was conducted using real-time polymerase chain reaction to determine the prevalence of the pathogen.

Over a 3-year period, the investigators identified 463 K pneumoniae isolates derived from 412 blood cultures, 21 body fluid cultures, and 30 abdominal wound specimens. Among these, 98 isolates were multidrug-resistant strains. A total of 18 isolates from 17 patients, including 2 from the index patient, screened positive for the 3 virulence genes being tested. Using wzi gene sequencing to determine capsular types of the positive isolates, 16 of 18 had capsular types were found to be associated with strains of a hypervirulent variant of K pneumonia. Furthermore, isolates from different patients were found to be different strains, indicating probable community acquisition. Significant morbidity was observed in 13 patients, 5 of whom died; 8 had coexisting hepatobiliary disease and 6 had diabetes mellitus.

The investigators concluded that despite this study being small in scope and from a single center, “its findings show the successful introduction of an invasive pathogen into a North American city, highlighting a pressing need for further epidemiological studies of [strains of a hypervirulent variant of K pneumoniae] in similar settings.” They also identified coexisting hepatobiliary disease to be a potential risk factor for these infections.


Parrott AM, Shi J, Aaron J, Green DA, Whittier S, Fu W. Detection of multiple hypervirulent Klebsiella pneumoniae strains in a New York City hospital through screening of virulence genes [published online May 24, 2020]. Clin Microbiol Infect. doi:10.1016/j.cmi.2020.05.012