Complete genome sequences of two clinical isolates from Egypt carrying on IncP and IncX4 plasmids.

Colistin is a last-resort antibiotic used in the treatment of multidrug resistant Gram-negative bacteria. However, the activity and efficacy of colistin has been compromised by the worldwide spread of the mobile colistin resistance genes ( to ). In this study, two clinical strains, named CAI51, and CAI73, harbored , showed multidrug-resistant phenotypes (with colistin MIC = 4 μg/ml), and belonged to phylogroup D: multilocus sequence type 1011 (ST1011) and phylogroup A: ST744, respectively. Findings revealed the existence of gene on two conjugable plasmids, pAMS-51-MCR1 (∼122 kb IncP) and pAMS-73-MCR1 (∼33 kb IncX4), in CAI51, and CAI73, respectively. The - element was detected in the two plasmids. Additionally, the composite transposon (IS-IS---IS) was identified only in pAMS-51-MCR1 suggesting the potential for horizontal gene transfer. The two strains carried from 16 to 18 different multiple acquired antimicrobial resistance genes (ARGs). Additionally, two different multireplicon virulence plasmids (∼117 kb pAMS-51-Vr and ∼226 kb pAMS-73-Vr) carrying the operon, the Salmochelin siderophore operon and other several virulence genes were identified from the two strains. Hierarchical clustering of core genome MLST (HierCC) revealed clustering of CAI73, and CAI51 with global lineages at HC levels of 50 (HC50) to 100 (HC100) core genome allelic differences. To the best of our knowledge, this study presented the first complete genomic sequences of -carrying IncP and IncX4 plasmids from human clinical isolates in Egypt. In addition, the study illustrated the broad dissemination in diverse plasmids and dissimilar clones.