Purpose
Understanding the horizontal transfer of resistance genes, such as
bla
NDM-5
, is pivotal in developing strategies to control the spread of resistance. In this study, we isolated two bacterial strains,
Escherichia coli
(designated GYB01) and
Klebsiella pneumoniae
(designated GYB02), from a single patient. The aim of our research is to explore the biological characteristics of these strains and to investigate the interspecies horizontal transfer of
bla
NDM-5
.
Materials and Methods
Strain identification and antimicrobial susceptibility testing were conducted using the Vitek 2 system. Both GYB01 and GYB02 were sequenced with the Illumina HiSeq platform. Bioinformatics analysis tools, including multilocus sequence typing, PlasmidFinder, ResFinder, and others, were utilized to analyze the strains. Additionally, conjugation assays and
Galleria mellonella
infection assays were employed to assess the strains.
Results
The isolates exhibited similar antimicrobial resistance profiles and both harbored the
bla
NDM-5
gene within the IncFIA plasmids (pGYB01-2, 165.8 kb and pGYB02-2, 211.6 kb, respectively). These plasmids (pGYB01-2 and pGYB02-2) shared over 99% homology, suggesting a common ancestral origin. Conjugation experiments confirmed the transferability of the
bla
NDM-5
carrying IncFIA plasmids among
Enterobacteriaceae
. GYB02 possessed an
iucACD-iutA
gene cluster, exhibited high virulence, and tested positive in the string test.
Conclusion
Our findings provide direct evidence of potential in vivo interspecies transfer of a multidrug-resistant plasmid, thus enriching our understanding of the mechanisms driving multidrug resistance (MDR) and aiding in the formulation of containment and treatment strategies.