Hypermucoviscous/hypervirulent and extensively drug-resistant QnrB2-, QnrS1-, and CTX-M-3-coproducing Klebsiella pneumoniae ST2121 isolated from an infected elephant (Loxodonta africana)

The rapid dissemination of extended-spectrum ß-lactamases (ESBLs)-producing Enterobacterales from different spheres worldwide over recent years has become a serious problem in both human and veterinary medicine. CTX-M-3-type ESBL has only been reported on few occasions, and in Brazil the blaCTX-M-3 gene has been identified only once in clinical strains. In this study, we aimed to molecularly characterize a hypermucoviscous (hm), hypervirulent (hv), and extensively drug-resistant (XDR) Klebsiella pneumoniae strain isolated from a lung tissue culture of an infected elephant. The A246 strain belonged to ST2121 and presented hm phenotype, hypervirulence-associated genes, and carried blaCTX-M-3 and plasmid-mediated quinolone resistance genes (qnrB2 and qnrS1) on an IncFII-IncQ1-IncM1 multireplicon plasmid (pA246-CTX-M-3, ~ 162 kb). A novel genetic context of blaCTX-M-3, in which a 482-bp ISEcp1 was truncated by an IS26, was also harbored by pA246-CTX-M-3. Furthermore, in vivo experiments revealed that the hm/hv A246 strain killed 100 % of the Galleria mellonella larvae at 72 h post-infection. Our findings evidence the intercontinental dissemination of a rare K. pneumoniae ST2121 and the multidrug resistance IncFII-IncQ1-IncM1 plasmid. Therefore, to the best of our knowledge, this is the first report of an XDR K. pneumoniae coproducing CTX-M-3, QnrB2, and QnrS1 isolated from captive wild animals.