Molecular identification of diarrheal Aeromonas using immuno magnetic polymerase chain reaction (IM-PCR) technique: a...

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

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

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.

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.

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.