Identification of Klebsiella oxytoca using a specific PCR assay targeting the polygalacturonase pehX gene

Area of Science:

• Microbiology
• Molecular Biology
• Clinical Diagnostics

Background:

• Bacteria of the genus Klebsiella are significant opportunistic pathogens causing hospital-acquired infections.
• Increasing antimicrobial resistance in Klebsiella species complicates treatment and necessitates accurate identification.
• Phenotypic identification methods often lead to frequent misidentifications among closely related Klebsiella species.

Purpose of the Study:

• To develop and validate a specific molecular method for distinguishing Klebsiella oxytoca from other Klebsiella species.
• To address the limitations of traditional phenotypic tests in routine clinical microbiology.

Main Methods:

• Development of a Polymerase Chain Reaction (PCR) assay targeting the polygalacturonase (pehX) gene.
• Testing the PCR assay on characterized strains of K. oxytoca, K. pneumoniae, K. planticola, K. ornithinolytica, K. terrigena, and Erwinia species.
• Validation of PCR results using key biochemical tests.
• Re-evaluation of misidentified strains from international collections.

Main Results:

• The pehX gene PCR assay successfully amplified a 344 bp amplicon in all 35 K. oxytoca strains tested.
• No amplification was observed in strains of K. pneumoniae, K. planticola/K. ornithinolytica, K. terrigena, or Erwinia species.
• Analysis of collection strains revealed six previously misidentified K. oxytoca strains.
• Biochemical tests confirmed the accuracy of the PCR-based identification.

Conclusions:

• The pehX gene PCR assay provides a specific and reliable method for identifying K. oxytoca.
• This assay can improve the accuracy of bacterial identification in clinical and ecological settings.
• The method aids in correcting misidentifications of collection strains and enhances microbial surveillance.