Burkholderia pseudomallei in Colombia: Laboratory Approaches to Enhance Diagnostic Accuracy

TL;DR

This study examines methods to improve the accuracy of diagnosing Burkholderia pseudomallei in Colombia, emphasizing the importance of molecular tools.

Contribution

The study highlights the limitations of commercial identification systems and advocates for molecular methods for accurate B. pseudomallei diagnosis.

Findings

PCR identified three B. pseudomallei isolates and 59 B. cepacia complex isolates.

Microscan and Vitek 2 Compact systems correctly identified B. pseudomallei, while Phoenix and MALDI-TOF Bruker systems did not.

Molecular tools are crucial for accurate diagnosis due to limitations in commercial systems and morphological similarities.

Abstract

Melioidosis is a challenging disease to diagnose, and diagnostic complications can delay treatment, adversely impacting patient outcomes.

Over a period of 1 year, 68 isolates, initially identified as Burkholderia spp. or oxidase-positive nonfermenting Gram-negative bacilli (excluding Pseudomonas aeruginosa), were collected from laboratories in three Colombian cities. Four commercial identification systems were employed. After recovery on blood agar, all strains were cultured on Ashdown's and CHROMID Colistin R media. Comparative identification using automated systems was performed, and definitive identification was achieved through multiplex PCR.

PCR identified three Burkholderia pseudomallei isolates and 59 Burkholderia cepacia complex isolates. The Microscan and Vitek 2 Compact systems successfully identified the B. pseudomallei isolates, whereas the Phoenix and MALDI-TOF Bruker systems did not. Ashdown's CHROM colistin media supported the growth of B. pseudomallei and various other genera and species. Species-level misidentifications were frequent.

Due to limitations of commercial identification systems and the morphological similarities between species, the use of molecular tools or a combination of confirmatory tests is crucial for accurately diagnosing B. pseudomallei in Colombia.

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