Complete genome sequence of Pseudomonas aeruginosa PA99 clinical isolate from Thailand carrying two novel class 1 integrons, In2083 and In2084.

OBJECTIVES

The aim of this study was to identify and characterize multidrug resistance genes and the genetic contexts of integrons found in extensively drug resistant (XDR) Pseudomonas aeruginosa PA99 clinical isolate from Thailand.

METHODS

The sequencing of P. aeruginosa PA99 genomic DNA was done by using Pacific Biosciences RS II sequencing platform. The generated reads were de novo assembled by Canu version 1.4 and the annotation was performed using Prokka v1.12b. The complete genome sequence was subjected for identification of sequence type, serotype, integrons, and antimicrobial resistance genes by MLST 2.0, PAst 1.0, INTEGRALL, Resfinder 4.1, and CARD 3.2.5, respectively.

RESULTS

Pseudomonas aeruginosa PA99 genome consisted of a 6,946,480-bp chromosomal DNA with 65.9% GC and belonged to ST964 and serotype O4. Twenty-one antimicrobial resistance genes conferring XDR phenotype were identified. Of special note were carbapenem resistance genes (bla, bla, bla, and bla) and colistin resistance gene basR with L71R mutation. Integron analysis revealed that P. aeruginosa PA99 harbored five class 1 integrons: two copies of In994 (bla), an In1575 (aadB), and two novel integrons, In2083 (bla - aac(6')-Ib3 - aac(6')-Ib-cr - ere(A)1∆2 - dfrA1r) and In2084 (bla - aac(6')-Ib3 - aac(6')-Ib-cr).

CONCLUSIONS

To the best of our knowledge, this is the first report of two novel class I integrons designated by INTEGRALL as In2083 and In2084 found in XDR-P. aeruginosa PA99 clinical isolate from Thailand. The characterization of genetic contexts of In2083 and In2084 provide the evidence of the assorting of resistance genes to evolve as novel integrons.