Structural Genomics of -Carrying IncFIB Family pA1705-, P911021-, and P1642-, Multidrug-Resistant Plasmids from .

BACKGROUND

Multidrug-resistant plasmids carrying replication genes have been widely present in various strains of and were found in plasmids belong to the IncFIB, but their detailed structural and genomic characterization was not reported yet. This is the first study that delivers structural and functional insights of and -carrying IncFIB plasmids.

METHODS

strains A1705, 911021, and 1642 were isolated from the human urine samples and bronchoalveolar fluids collected from different hospitals of China. Antibacterial susceptibility and plasmid transfer ability were tested to characterize the resistant phenotypes mediated by the pA1705-, p911021-, and p1642-. The complete nucleotide sequences of these plasmids were determined through high-throughput sequencing technology and comparative genomic analyses of plasmids belong to the same incompatibility group were executed to extract the genomic variations and features.

RESULTS

The pA1705-, p911021-, and p1642- are defined as non-conjugative plasmids, having two replication genes, and associated with IncFIB family, and unknown incompatible group, respectively. Comparative genomic analysis revealed that relatively small backbones of IncFIB plasmids integrated massive accessory module at one "hotspot" that was located between and . These IncFIB plasmids exhibited the distinct profiles of accessory modules including one or two multidrug-resistant regions, many complete and remnant mobile elements comprising integrons, transposons and insertion sequences. The clusters of resistant genes were recognized in this study against different classes of antibiotics including β-lactam, phenicol, aminoglycoside, tetracycline, quinolone, trimethoprim, sulfonamide, tunicamycin, and macrolide. It has been observed that all resistant genes were located in multidrug resistance regions.

CONCLUSION

It is concluded that multidrug-resistant and -carrying IncFIB plasmids are a key source to mediate the resistance through mobile elements among . Current findings provide a deep understanding of horizontal gene transfer among plasmids of the IncFIB family via mobile elements that will be utilized in further in vitro studies.