A new, hypervirulent clinical variant of Klebsiella pneumoniae (hvKP) has emerged over the last decade. Initial reports were from the """"""""Pacific Rim"""""""", but more recently hvKP has been described in the United States, Canada, Europe, Israel, Australia, South Africa and elsewhere. At first, infection due to hvKP was characterized and distinguished from traditional infections due to """"""""classical"""""""" K. pneumoniae (cKP) by: 1) presenting as community-acquired hepatic abscess, 2) affecting patients lacking a history of hepatobiliary disease, and 3) a propensity for causing metastatic spread to distant sites in 11-80% of cases (e.g. eyes, central nervous system (CNS), &others). More recently, hvKP has also been described to cause a variety of serious extrahepatic abscesses/infections as well. hvKP is associated with a significant mortality rate, ranging from 3-32% depending on the study. Survivors with metastatic spread often suffer catastrophic morbidity such as loss of vision and neurologic sequelae. From a clinical perspective, hvKP possesses novel features for an enteric Gram-negative bacillus (GNB). Metastatic spread is common for certain Gram-positive pathogens such as Staph and Strep, but is uncommon enteric GNB (e.g. E. coli and cKP). The basis for this change is poorly understood. One of the goals of this proposal is to fill that knowledge gap by identifying novel or unrecognized pathogenic traits of hvKP that contribute to its hypervirulence. Compounding an already challenging clinical situation is the recent propensity of K. pneumoniae to become multi-dug resistant (MDR), including the acquisition of extended-spectrum beta-lactamases and carbapenemases. Some cases of infection due to hvKP caused by MDR-strains have already been described and as expected, outcome is worse with inappropriate treatment. As a result, management of infections due to hvKP will become extremely increasing challenging and morbidity and mortality rates will increase. The confluence of hypervirulence and MDR in hvKP has the potential to create a """"""""post-antibiotic"""""""" scenario;similar to what was feared with methicillin resistant Staphylococcus aureus (MRSA) but was never realized. Therefore, enhancing our understanding of this highly virulent pathogen is critical. A novel and efficient approach is used to identify both new or unrecognized virulence factors that are specific for hvKP and are essential for extraintestinal growth/survival in vitro and in vivo. Subsequently these virulence factors will undergo initial characterization. These data will be important and unique, and will lay the foundation for understanding the biology of this new and frightening clinical variant.

Public Health Relevance

A new, hypervirulent clinical variant of Klebsiella pneumoniae (hvKP) has emerged over the last decade that is distinguished from traditional infections due to classical K. pneumoniae (cKP) by presenting as community-acquired hepatic and extraheptatic abscesses and a propensity for causing metastatic spread to distant sites (e.g. eyes, central nervous system (CNS), &others);a highly unusual feature for Gram-negative bacilli. Further, some cases of infection due to hvKP have been caused by multi-drug resistant (MDR) strains, a trend that will undoubtedly increase making treatment challenging. Therefore, the goal of this project is fill critical knowledge gaps on the biology of hvKP by identifying and initially characterizing hvKP-specific novel/unrecognized genes that contribute to its in vivo growth/survival;information required to logically combat this emerging pathogen.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI088318-02
Application #
8306689
Study Section
Special Emphasis Panel (ZRG1-IDM-A (80))
Program Officer
Taylor, Christopher E,
Project Start
2011-08-01
Project End
2014-07-31
Budget Start
2012-08-01
Budget End
2014-07-31
Support Year
2
Fiscal Year
2012
Total Cost
$198,125
Indirect Cost
$73,125
Name
State University of New York at Buffalo
Department
Internal Medicine/Medicine
Type
Schools of Medicine
DUNS #
038633251
City
Buffalo
State
NY
Country
United States
Zip Code
14260
Bulger, Jeffrey; MacDonald, Ulrike; Olson, Ruth et al. (2017) Metabolite Transporter PEG344 Is Required for Full Virulence of Hypervirulent Klebsiella pneumoniae Strain hvKP1 after Pulmonary but Not Subcutaneous Challenge. Infect Immun 85:
Russo, Thomas A; Olson, Ruth; MacDonald, Ulrike et al. (2015) Aerobactin, but not yersiniabactin, salmochelin, or enterobactin, enables the growth/survival of hypervirulent (hypermucoviscous) Klebsiella pneumoniae ex vivo and in vivo. Infect Immun 83:3325-33
Russo, Thomas A; Olson, Ruth; Macdonald, Ulrike et al. (2014) Aerobactin mediates virulence and accounts for increased siderophore production under iron-limiting conditions by hypervirulent (hypermucoviscous) Klebsiella pneumoniae. Infect Immun 82:2356-67
Shon, Alyssa S; Bajwa, Rajinder P S; Russo, Thomas A (2013) Hypervirulent (hypermucoviscous) Klebsiella pneumoniae: a new and dangerous breed. Virulence 4:107-18
Russo, Thomas A; Beanan, Janet M; Olson, Ruth et al. (2013) The K1 capsular polysaccharide from Acinetobacter baumannii is a potential therapeutic target via passive immunization. Infect Immun 81:915-22
Pomakova, D K; Hsiao, C-B; Beanan, J M et al. (2012) Clinical and phenotypic differences between classic and hypervirulent Klebsiella pneumonia: an emerging and under-recognized pathogenic variant. Eur J Clin Microbiol Infect Dis 31:981-9
Kong, Qingli; Beanan, Janet M; Olson, Ruth et al. (2012) Biofilm formed by a hypervirulent (hypermucoviscous) variant of Klebsiella pneumoniae does not enhance serum resistance or survival in an in vivo abscess model. Virulence 3:309-18
Shon, Alyssa S; Russo, Thomas A (2012) Hypervirulent Klebsiella pneumoniae: the next superbug? Future Microbiol 7:669-71
Russo, Thomas A; Shon, Alyssa S; Beanan, Janet M et al. (2011) Hypervirulent K. pneumoniae secretes more and more active iron-acquisition molecules than ""classical"" K. pneumoniae thereby enhancing its virulence. PLoS One 6:e26734