Ampicillin-susceptible Enterococcus faecium infections: clinical features, causal clades, and contribution of MALDI-TOF to early detection

作者：Hélène Faury, Ronan Le Guen, Vanessa Démontant, Christophe Rodriguez, Bérénice Souhail, Adrien Galy, Sarah Jolivet, R. Lepeule, Jean‐Winoc Decousser, Vincent Fihman, Paul‐Louis Woerther, Guilhem Royer · 发表于：Microbiology Spectrum · 年份：2023 · DOI：10.1128/spectrum.04545-22 · 被引用次数：11 · 研究领域：Antimicrobial Resistance in Staphylococcus、Bacterial Identification and Susceptibility Testing、Mycobacterium research and diagnosis

ABSTRACT Enterococcus faecium, a common resident of the human gastrointestinal tract, is also a major pathogen. Prompt initiation of appropriate treatment is essential to improve patient outcome in disseminated E. faecium infections. However, ampicillin resistance is frequent in this species, rendering treatment difficult. We used a comprehensive approach, including clinical data review, whole-genome sequencing, and mass spectrometry, to characterize ampicillin-susceptible (EFM-S) and ampicillin-resistant (EFM-R) isolates. We included all patients with culture-confirmed E. faecium infection attending our hospital over a 16-month period. A comparison of 32 patients infected with EFM-S strains and 251 patients infected with EFM-R strains revealed that EFM-R isolates were strongly associated with a longer hospital stay, history of prior hospitalization, and the carriage of multidrug-resistant organisms. An analysis of the genomes of 26 EFM-S and 26 EFM-R isolates from paired patients revealed a population structure almost perfectly matching ampicillin susceptibility, with resistant isolates in clade A1, and susceptible isolates in clades A2 and B. The clade B and A2 isolates mostly came from digestive or biliary tract samples, whereas clade A1 isolates were mostly obtained from urine and blood. Finally, we built a custom database for matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS), which differentiated between clade B and clade A1/A2 s...