Rapid real-time PCR assays for detection of Klebsiella pneumoniae with the rmpA or magA genes associated with the hypermucoviscosity phenotype: screening of nonhuman primates

J Mol Diagn. 2009 Sep;11(5):464-71. doi: 10.2353/jmoldx.2009.080136. Epub 2009 Jul 30.

Abstract

The relationship of mucoviscosity-associated (magA) and/or regulator of mucoid phenotype (rmpA) genes to the Klebsiella pneumoniae hypermucoviscosity (HMV) phenotype has been reported. We previously demonstrated that rmpA+ K. pneumoniae can cause serious disease in African green monkeys and isolated rmpA+ and magA+ HMV K. pneumoniae from other species of non-human primates. To rapidly screen African green monkeys/non-human primates for these infections, we developed three real-time PCR assays. The first was K. pneumoniae-specific, targeting the khe gene, while the others targeted rmpA and magA. Primer Express 2 was used with the three K. pneumoniae genes to generate sequence-specific TaqMan/TaqMan-Minor Groove Binder assays. Oral/rectal swabs and necropsy samples were collected; swabs were used for routine culture and DNA extraction. K. pneumoniae colonies were identified on the Vitek 2 with DNA tested using the K. pneumoniae-specific assays. Testing of 45 African green monkeys resulted in 19 khe+ samples from 14 animals with none positive for either rmpA or magA. Of these 19 khe+ samples, five were culture-positive, but none were HMV "string test"-positive. Subsequent testing of 307 non-human primates resulted in 64 HMV K. pneumoniae isolates of which 42 were rmpA+ and 15 were magA+. Non-human primate testing at the U.S. Army Medical Research Institute of Infectious Diseases demonstrated the ability to screen both live and necropsied animals for K. pneumoniae by culture and real-time PCR to determine HMV genotype.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Bacterial Proteins / genetics*
  • Chlorocebus aethiops
  • Klebsiella Infections / diagnosis*
  • Klebsiella Infections / microbiology*
  • Klebsiella pneumoniae / genetics*
  • Klebsiella pneumoniae / isolation & purification
  • Phenotype
  • Polymerase Chain Reaction / methods*
  • Primates
  • Viscosity

Substances

  • Bacterial Proteins
  • MagA protein, Klebsiella pneumoniae
  • RmpA protein, Klebsiella pneumoniae