Resistance of Klebsiella pneumoniae to the innate immune system of African green monkeys

Brandi L. Cox, Holly Schiffer, Gregory Dagget, Amy Beierschmitt, Fortune Sithole, Elise Lee, Floyd Revan, Iona Halliday-Simmonds, Janet Beeler-Marfisi, Roberta Palmour, Esteban Soto Martinez

Research output: Contribution to journalArticlepeer-review

9 Scopus citations


In recent years, an emergent Klebsiella pneumoniae hypermucoviscosity (HMV) phenotype has been associated with increased invasiveness and pathogenicity in primates. In this project, bacteria recovered from infected African green monkeys (AGM) (Chlorocebus aethiops sabaeus) were screened for HMV phenotype, and were compared to non-HMV isolates in in vitro, serum, and oxidative-mediated killing assays. Complement-mediated killing was assessed utilizing freshly collected serum from healthy AGM. Oxidative-mediated killing was investigated utilizing sodium hypochlorite and hydrogen peroxide. Compared to non-HMV isolates, HMV isolates were more resistant to serum-mediated and oxidative killing (p<. 0.05). Phagocytosis resistance was evaluated using AGM peripheral blood monocytes (PBMC), and results indicated that non-HMV isolates associated with the AGM PBMC to a greater extent than HMV isolates (p<. 0.001). Measurement of lactate dehydrogenase release showed that HMV isolates were more cytotoxic to AGM PBMC than non-HMV isolates (p<. 0.001). Thus, the hypermucoid phenotype appears to be an important virulence factor that promotes evasion of innate immune defenses.

Original languageEnglish (US)
Pages (from-to)134-142
Number of pages9
JournalVeterinary Microbiology
Issue number1-2
StatePublished - Mar 23 2015
Externally publishedYes


  • Cytotoxicity
  • Hypermucoviscosity
  • Oxidative killing
  • Phagocytosis
  • Serum resistance

ASJC Scopus subject areas

  • Microbiology
  • veterinary(all)
  • Medicine(all)


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