Characteristics of Oral spp. and Evolution of Plasmid-Mediated Carbapenem Resistance in Bacteremia Patients with Hematological Malignancies.

BACKGROUND

Patients with hematological malignancies are more susceptible to infections, leading to a poor prognosis. colonization is a risk factor for secondary bacteremia.

METHODS

Antibiotic susceptibility phenotypes and genomic characteristics of 48 oral spp. and one bloodstream from patients with hematological malignancies were analyzed by antimicrobial susceptibility tests and whole-genome sequencing. We conducted comparative genomic analysis of oral and blood isolates from the same patient.

RESULTS

was the most common (72.92%, 35/48) species in oral spp. isolates. Seventeen different sequence types were identified using the Pasteur MLST scheme; however, the dominant global clones GC1 and GC2 were not present. Among the isolates, 46 (95.8%) were carbapenem-susceptible spp. One patient treated with meropenem for 15 days developed bacteremia 46 days after the isolation of oral AOR07. Oral and bloodstream isolates from the same patient were closely related to only four non-synonymous mutations on the chromosome. The gene was transferred between plasmids through XerCD-mediated recombination, leading to an elevated copy number, causing carbapenem resistance in bloodstream isolates.

CONCLUSION

Oral spp. may cause secondary bacteremia. The amplification and transfer of in the plasmids explained the increased carbapenem resistance in the bloodstream isolate.