Characterization of Hypermucoviscous Klebsiella pneumoniae Recovered from California Sea Lions (Zalophus californianus) in California, USA
IAAAM 2016
Esteban Soto1*; Christine A. Richey1; Kirsten V. Kenelty1; Brittany N. Stevens1; Dane Whitaker1; Katherine Prager2; James O. Lloyd-Smith2; Christine Kreuder-Johnson1; Shawn Johnson3; Carlos Rios3; Robert DeLong4; Barbie Halaska3; Lauren Rust3; Barbara Byrne5; Matt J. Griffin6
1Department of Medicine and Epidemiology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA; 2Department of Ecology and Evolutionary Biology, University of California-Los Angeles, Los Angeles, CA, USA; 3The Marine Mammal Center, Sausalito, CA, USA; 4National Marine Mammal Laboratory/AFSC/NMFS/NOAA, Seattle, WA, USA; 5Department of Pathology, Microbiology, and Immunology, School of Veterinary Medicine, University of California-Davis, Davis, CA, USA; 6Department of Pathobiology and Population Medicine, College of Veterinary Medicine, Mississippi State University, Stoneville, MS, USA


Klebsiella pneumoniae (Kp) is a gram-negative, facultative anaerobic bacterium belonging to the family Enterobacteriaceae. In both human and veterinary medicine, this bacterium is regarded as an emergent and common nosocomial pathogen.1-9 A novel, invasive and hypervirulent form of Kp associated with the hypermucoviscosity (HMV) phenotype has emerged over the last two decades.4,6,8,9 The HMV phenotype is mainly associated with K1, K2, and K5 capsular serotypes, and with several virulence genes including the rmpA, magA and wacG genes.3,8,9 While fatal multisystemic abscesses caused by HMV Kp have been reported in multiple marine mammal species found throughout the North-Pacific coast of the US3, very little is known about the pathogenesis and ecology of HMV Kp infection in these free-ranging hosts.1-3,8 Knowledge of virulence genes associated with pathogenic bacteria improves pathogen characterization and can provide researchers with specific genetic markers for use in molecular epidemiological studies.7,9 Kp isolates with the HMV phenotype, that were PCR positive for the rmpA and the K2 serotype associated gene wyz have been reported as the etiologic agent of suppurative pneumonia, pleuritis and abscesses in California sea lions (CSL) (Zalophus californianus).3 Since 1996 Kp has been isolated in over 200 diagnosed cases of klebsiellosis at the Marine Mammal Center, Sausalito, CA. CSL (n = 128) and Pacific harbor seals (PHS) (Phoca vitulina) (n = 54) accounted for ~ 90% of the cases. In > 90% of the cases, bacterial septicemia, meningitis, pneumonia, pleuritis, pyothorax or renal failure was suspected as the cause of death, highlighting the likely role Kp played as the etiologic agent of these conditions. Some of these isolates have been saved in the UC Davis Veterinary Teaching Hospital Microbiology collection3, however, they are un-characterized and heterogeneity is unknown. The main objective of this study was to characterize HMV Kp isolates recovered during 2015 in free-ranging and in stranded populations of CSL. The genotype, serotype and antimicrobial susceptibility of over 30 Kp isolates obtained from both clinically ill and apparently healthy hosts from 2000 to 2015 was investigated using molecular methods and the broth microdilution method. This line of work improves our understanding of potential Kp reservoirs, as well as the source and circulation of antimicrobial-resistant strains of Kp and their genetic determinants of resistance. The majority of HMV Kp isolates recovered from CSL was found to be positive for the rmpA and K2 associated gene (wyz); however, several of the recovered isolates were also found to be PCR positive for the rmpA and K1 serotype associated gene (magA), demonstrating that more than one type of HMV Kp is associated with marine mammals in CA.

* Presenting author

Literature Cited

1.  Castinel A, Duignan PJ, Pomroy WE, Lopez-Villalobos N, Gibbs HJ, Chilvers BL, Wilkinson IS. Neonatal mortality in New Zealand sea lions (Phocarctos hookeri) at Sandy Bay, Enderby Islands from 1998 to 2005. J Wildl Dis. 2007;43(3):461–474.

2.  Castinel A, Grinberg A, Pattison R, Duignan P, Pomroy B, Rogers L, Wilkinson I. Characterization of Klebsiella pneumoniae isolates from New Zealand sea lion (Phocarctos hookeri) pups during and after the epidemics on Enderby Island, Auckland Islands. Vet Microbiol. 2007;122(1–2):178–184.

3.  Jang S, Wheeler L, Carey RB, Jensen B, Crandall CM, Schrader KN, Jessup D, Colegrove K, Gulland FM. Pleuritis and suppurative pneumonia associated with a hypermucoviscosity phenotype of Klebsiella pneumoniae in California sea lions (Zalophus californianus). Vet Microbiol. 2010;141(1–2):174–177.

4.  Kawai T. Hypermucoviscosity: an extremely sticky phenotype of Klebsiella pneumoniae associated with emerging destructive tissue abscess syndrome. Clin Infect Dis. 2006;42(10):1359–1361.

5.  Kochar S, Sheard T, Sharma R, Hui A, Tolentino E, Allen G, Landman D, Bratu S, Augenbraun M, Quale J. Success of an infection control program to reduce the spread of carbapenem-resistant Klebsiella pneumoniae. Infect Control Hosp Epidemiol. 2009;30(5):447–452.

6.  Lederman ER, Crum NF. Klebsiella liver abscess: a coast-to-coast phenomenon. Clin Infect Dis. 2005;41(2):273.

7.  Podschun R, Ullmann U. Klebsiella spp. as nosocomial pathogens: epidemiology, taxonomy, typing methods, and pathogenicity factors. Clin Microbiol Rev. 1998;11(4):589–603.

8.  Roe WD, Rogers L, Pinpimai K, Dittmer K, Marshall J, Chilvers BL. Septicaemia and meningitis caused by infection of New Zealand sea lion pups with a hypermucoviscous strain of Klebsiella pneumoniae. Vet Microbiol. 2015;176(3–4):301–308.

9.  Simoons-Smit AM, Verweij-van Vught AM, MacLaren DM. The role of K antigens as virulence factors in Klebsiella. J Med Microbiol. 1986;21(2):133–137.


Speaker Information
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Esteban Soto, DVM, PhD, DACVIM
Department of Medicine and Epidemiology
School of Veterinary Medicine
University of California-Davis
Davis, CA, USA

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