Enterococcal pyogenic liver abscesses: high risk of treatment failure and mortality

Enterococci are the most frequent gram-positive bacteria recovered from pyogenic liver abscesses (PLA). This study aims to analyze the impact of the presence of Enterococcus spp. on PLA outcome. We retrospectively analyzed the characteristics and outcome of all PLA cases in which Enterococcus spp. was isolated between January 2010 and September 2019 in a French university hospital and compared them to PLA without Enterococcus spp. Enterococci were recovered from 68 of the 359 (19%) PLA cases. Among the 78 isolates, Enterococcus faecalis (n = 37, 47.7%) and Enterococcus faecium (n = 32, 41%) were the most frequent. Enterococcal PLA were more often of biliary origin (79.4% versus 54.6%, p < 0.001) or post-surgical (35.3% versus 18.6%, p = 0.004). Multivariate analysis showed an independent association between the isolation of Enterococcus spp. and 3-month mortality (HR 2.51, p = 0.011), primary failure (HR 2.15, p = 0.006), but not with relapses (HR 0.86, p = 0.739). In the subgroup of enterococcal PLA, portal vein thrombosis was the only factor significantly associated with 3-month mortality (univariate HR 3.45, p = 0.023) or primary treatment failure (multivariate, HR 4.02, p = 0.006). Enterococcus spp. identification in a PLA is associated with a higher mortality and primary treatment failure.