1175. Clinical and Microbiological Features of Klebsiella pneumoniae Liver Abscess Caused by Multidrug-Resistant Strains

Abstract

BackgroundThe endemic Klebsiella pneumoniae liver abscess (KPLA) in East Asian countries are usually caused by hypervirulent strains. These hypervirulent strains are usually susceptible to commonly used antibiotics, aside from their intrinsic resistance to ampicillin. However, hypervirulent K. pneumonaie strains with multidrug-resistant (MDR) phenotype has been reported recently. We aim to investigate clinical and microbiological features of KPLA caused by MDR-resistant strains, and the evolution of drug-resistance in the resistant strain causing recurrent KPLA.MethodsPatients with KPLA were retrospectively identified at Taipei Veterans General Hospital during January 2013 to February 2018. Capsular genotypes were analyzed in all K. pneumoniae isolates. Antimicrobial-resistant mechanisms were determined for MDR isolates. Pulse-field gel electrophoresis (PFGE), conjugation experiment, and in vivo mice lethality were determined on the strains from a patient with recurrent infection.ResultsDuring the study period, a total of 211 patients with KPLA, and five patients with recurrence were identified. Most of K. pneumoniae isolates (n = 175, 83.3%) belonged to capsular type K1/K2/K5/K20/K54/K57. Nineteen MDR strains were identified and 15 of them had virulent capsular types (K1 = 7, K2 = 5, K5 = 2, K54 = 1). The major resistance mechanisms of these MDR strains involved the presence of β-lactamases and the overexpression of efflux pumps. The in-hospital mortality of KPLA caused by MDR strains was not significantly higher than wild-type stains (10.53% vs. 4.69%, P = 0.275). In a case with recurrent KPLA, the recurrent capsular type K1 strain (TVGHKP2611) with blaSHV-12 was genetically identical to the primary wild-type resistance strain (TVGHKP2329) by PFGE. The SHV-12-carrying plasmid from TVGHKP2611 was successfully conjugated to Eschericia coli J53. TVGHKP2611 retained high virulence similar to TVGHKP2329 in mice lethality study (median lethal dose < 500 CFU) despite carrying the resistance determinant.ConclusionMDR K. pneumoniae strains belonging to virulent capsular types have emerged in KPLA. One SHV-12 producing capsular K1 strain causing recurrent KPLA retained its high virulence, which signals this highly pathogenic and resistant strain could be a major concern in the future.Disclosures All authors: No reported disclosures.