LAUSR

Abstract Pseudomonas aeruginosa is a notorious Gram-negative opportunistic pathogen that normally causes acute and chronic infections in a wide range of hosts. In this study, a multi-resistant P. aeruginosa isolate L1a harboring an infrequent plasmid with red fluorescence was obtained from the bronchoalveolar lavage fluid of a patient with chronic obstructive pulmonary disease. The results of susceptibility testing and virulence-related phenotypic identification revealed that P. aeruginosa L1a was resistant to levofloxacin, cefepime, aztreonam, and imipenem and showed significantly stronger capacities for swimming and pyocyanin production than the reference strain PAO1. The genome of P. aeruginosa L1a was assembled into one circular chromosome (6,216,913 bp) and one circular plasmid (9111 bp). P. aeruginosa L1a was found to belong to the multilocus sequence type ST549, and serotype O5, and carried 8 drug resistance genes and 18 multidrug efflux pump-related genes in the chromosomal DNA. The plasmid pL1a harbored a tetracycline resistant gene tetA and a functional red fluorescence protein. This study reports a multidrug resistant P. aeruginosa clinical isolate harboring an infrequent red fluorescence plasmid for the first time.