Rapid identification and drug resistance of Burkholderia in food

Objective To explore the rapid identification method of Burkholderia, and the distribution in food and drug resistance of Burkholderia.

Methods Primers were designed according to RNA polymerase beta-subunit encoding gene ( rpoB ) of type strains, and the rpoB gene of strains isolated from food was amplified, then a phylogenetic tree was built based on rpoB gene. Matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was used for the rapid identification of food isolates. Resistance phenotype was detected with micro-broth dilution method.

Results At species level, the concordance rate of rpoB gene and genome identification could reach 100.00%. The accuracy of MALDI-TOF MS was 73.47% (36/49), and there were misjudgments among the species of Burkholderia cepacia complex (Bcc). The strains isolated from food showed multidrug resistance, and the MIC of most antibiotics to Bcc strains was much higher than that to B. gladioli, but ceftazidime had opposite MIC.

Conclusion MALDI-TOF MS can be used for rapid and accurate identification of Burkholderia at genus level, and then the species was identified by rpoB gene. Multidrug-resistant species of Burkholderia has been detected in food, suggesting that the surveillance for Burkholderia in food should be strengthened.