Epidemiology and clinical significance of pLVPK-like virulence plasmid in KPC-2-producing Klebsiella pneumoniae infections in eastern China: a preliminary exploration

Abstract Background: By acquiring a pLVPK-like virulence plasmid (pVir), Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae (KPC-kp) evolves to a hypervirulent variant, with increasing cases reported worldwide. However, little is known about the epidemiological trend of pVir in KPC-kp, as well as clinical characteristics of infections caused by this novel strain (pVir+-KPC-kp). Methods: From 2014-2018, 662 carbapenem-resistant K. pneumoniae (CRKP) were consecutively collected from a tertiary hospital of eastern China. The confirmed KPC-kp were subjected to antimicrobial susceptibility testing, multilocus sequence typing and detection of pLVPK-related genetic loci (rmpA, rmpA2, iucA and iroN) to identify pVir+-KPC-kp strains. Then, the clinical characteristics and outcomes of KPC-kp infection patients with and without pVir were compared. Moreover, the risk factors for pVir+-KPC-kp infections also determined by a multivariable logistic regression analysis.Results: of the 662 CRKP, 86.6% (573/662) were KPC-kp including 285 (49.7%) pVir+-KPC-kp and 288 (50.3%) pVir--KPC-kp. Notably, the prevalence of pVir+-KPC-kp by year increased remarkably from 2014 (19.5%, 8/41) to 2018 (60.0%, 90/150). Sequence type (ST) 11 was the most predominant ST, accounting for 88.9% of all pVir+-KPC-kp. For the 352 KPC-kp infection cases (186 with pVir+-KPC-kp and 166 with pVir--KPC-kp), multivariable analysis indicated neurosurgery (Odds ratio [OR], 2.92; 95% confidence interval [CI], 1.48-5.75; P =0.002) was independently associated with pVir+-KPC-kp infections. Although patients with pVir+-KPC-kp infections had higher incidence of septic shock (31.2% vs. 21.1%, P =0.03), the two groups showed no significant differences in 7-day mortality (23.1% vs. 18.1%, P =0.24) or 28-day mortality (45.7% vs. 44.0%, P =0.75). Conclusions: Altogether, wide dissemination of pVir in ST11 KPC-kp has emerged in China. Neurosurgery is an independent risk factor for acquisition of pVir+-KPC-kp infections. The mortality rates were similar between patients infected with pVir+-KPC-kp or pVir--KPC-kp, suggesting uncertain impact of pVir in clinical outcome.