Molecular identification of diarrheal Aeromonas using immuno magnetic polymerase chain reaction (IM-PCR) technique: a comparative study with conventional culture method

Afr Health Sci. 2019 Jun;19(2):2036-2042. doi: 10.4314/ahs.v19i2.27.

Abstract

Background: Aeromonas are ubiquitous bacteria causing many clinical conditions including acute diarrhea. Diarrheagenic Aeromonas harbors aerolysin gene secreting virulent enterotoxin, aerolysin.

Objectives: To develop a molecular and immunological based method for detection of Aeromonas.

Methods: Diarrheal Aeromonas strains were identified from stool samples using culture, enterotoxicity testing using mice model. During immune magnetic polymerase chain reaction IM-PCR protocol, aerolysin specific antibodies were bound with immuno magnetic binding. Sensitivity and specificity tests for IM-PCR were conducted.

Results: There was high detection of Aeromonas using IM-PCR (12.4 %) technique when compared to low isolation with culture (5.1%). Our study confirmed that some strains of enterotoxic Aeromonas strains were uncultivable. Enterotoxicity tests on culture isolates revealed many strains were negative. IM-PCR detected high, (62/500) rate of identification of Aeromonas with aerolysin toxin gene. Aeromonas species identified after IM-PCR were A. hydrophila (40.3% ), A. veronii (17.7 %), A. caviae (14.5 %), A. trota (11.2 %), A. jandei (9.6 %) and A. schuberti (6.4%). All A. trota strains were undetected by cultivation.

Conclusion: High sensitivity and specificity of IM-PCR are due to preparation of aerolysin antibodies and immuno magnetic binding, prior to PCR. Since diseases due to Aeromonas are increasingly reported, IM-PCR is recommended for detection from clinical specimens.

Keywords: Aeromonas; IM-PCR; acute diarrhea; aerolysin; enterotoxicity.

MeSH terms

  • Aeromonas / genetics*
  • Aeromonas / isolation & purification
  • Animals
  • Bacterial Toxins / genetics*
  • Diarrhea / microbiology*
  • Ethiopia
  • Genes, Bacterial
  • Humans
  • Magnetic Phenomena
  • Mice
  • Polymerase Chain Reaction / methods*
  • Pore Forming Cytotoxic Proteins / genetics*
  • Rabbits
  • Sensitivity and Specificity

Substances

  • Bacterial Toxins
  • Pore Forming Cytotoxic Proteins
  • aerolysin