Search Results (4)

Daptomycin (DAP) is a therapeutic option for vancomycin-resistant Enterococcus faecium (VRE) infections, but DAP resistance may occur during treatment. Previously, we identified a mutation within the E. faecium lafB gene that induces hypersusceptibility to DAP. The lafB gene encodes a glycosyltransferase involved in lipoteichoic acid anchor synthesis, which makes it a promising target for enhancing DAP efficacy. In this study, we characterized E. faecium LafB protein (EfLafB) biophysical properties, used AlphaFold3 to predict LafB in silico three-dimensional structure, and determined lafB gene mutation’s role in virulence, comparing E. faecium HBSJRP18 (DAP-hypersusceptible) and a lafB revertant, HBSJRP18_2.7, and analyzing bacterial growth kinetics, biofilm formation ability, and virulence in a Galleria mellonella model. After gene cloning and expressing and purifying EfLafB, circular dichroism and SEC-MALS assays revealed its monomeric nature under in vitro conditions, with approximately a 40 kDa molecular mass and a melting temperature of 50 °C. In silico prediction indicated that LafB is an αβ-type protein with two domains conforming to the GT-4 family glycosyltransferases. These results are further supported by the highly conserved amino acids (E257, D91, R184, and K185), likely involved in UDP-Glc binding. The studied lafB gene mutation resulted in a significant decrease in bacterial growth and virulence in the invertebrate model. Full article

Vancomycin-variable enterococci (VVE), though genetically containing van genes, are phenotypically sensitive to vancomycin. If VVE is undetected or does not grow on the vancomycin-resistant enterococci (VRE) selection medium, or both, it can acquire resistance upon exposure to vancomycin. This characteristic is clinically important for the treatment and prevention of VRE. This study aims to analyze the prevalence and characteristics of VVE in Korea through the Global Antibiotic Resistance Surveillance System (Kor-GLASS) and emphasize the importance of VVE. A total of 3342 enterococcal bloodstream isolates were collected through the Kor-GLASS between 2017 and 2022. Antibiotic susceptibility testing, van gene detection, and multilocus sequence typing were conducted with all the isolates. The trends in the domestic prevalence of VVE were analyzed and compared with global prevalence data. Among the isolates, 197 (5.9%), including 124 Enterococcus faecium and 73 E. faecalis, were identified as VVE. While the VRE incidence has declined in Korea since 2020, the VVE incidence is significantly rising. In Korea, only the vanA gene has been detected in both VRE and VVE, and no other van gene variants have been identified. Most of these isolates belong to CC17 (91.3%), with ST17, ST817, and ST80 as the predominant types. We have shown that continuous surveillance is essential in Korea due to the persistently high prevalence of VRE and the potential evolution of VVE into VRE. Consequently, it is critical to evaluate Enterococcus species isolated from domestic clinical settings for their phenotypic vancomycin resistance and the molecular detection of van genes, irrespective of the strain. Full article

Vancomycin-resistant enterococci (VRE) pose a public health challenge worldwide. While VRE bloodstream infections (VREBI) increase in Germany and Europe, population-based molecular data are scarce. We aimed to analyze the molecular epidemiology, demographic aspects, and geographical distribution of VREBI in the German Federal State of North-Rhine–Westphalia (NRW), located in the German–Dutch–Belgian border area, representing over 20% of Germany’s population. VREBI isolates were collected from hospitals across NRW between 2016 and 2019. Demographic data were gathered and anonymized upon sample collection. Multilocus sequence typing (MLST) and identification of glycopeptide resistance were carried out. Epidemiological analysis and geographical mapping were performed. Single VREBI isolates from 755 patients were analyzed. In total, 38.9% were female, and 80.0% were aged ≥ 60 years. The VREBI incidence per 100,000 inhabitants nearly tripled, from 0.52 (2016) to 1.48 (2019), particularly in male patients aged ≥ 50 years. The proportion of vanB reached 83% (n = 202/243) in 2018, overtaking vanA as the predominant glycopeptide resistance determinant, detected in close relation with ST117 isolates. The proportion of MLST sequence type (ST) 117 peaked in 2018, at 78.2% (n = 190/243). The major role of these emerging strains in invasive infections in central Europe requires novel strategies for their diagnosis, treatment, and prevention. Full article

Broad-spectrum antibiotics administered to patients with severe COVID-19 pneumonia pose a risk of infection caused by Clostridioides difficile. This risk is reduced mainly by strict hygiene measures and early de-escalation of antibiotic therapy. Recently, oral vancomycin prophylaxis (OVP) has also been discussed. This retrospective study aimed to assess the prevalence of C. difficile in critical COVID-19 patients staying in an intensive care unit of a tertiary hospital department of anesthesiology, resuscitation, and intensive care from November 2020 to May 2021 and the rates of vancomycin-resistant enterococci (VRE) after the introduction of OVP and to compare the data with those from controls in the pre-pandemic period (November 2018 to May 2019). During the COVID-19 pandemic, there was a significant increase in toxigenic C. difficile rates to 12.4% of patients, as compared with 1.6% in controls. The peak rates were noted in February 2021 (25% of patients), immediately followed by initiation of OVP, changes to hygiene precautions, and more rapid de-escalation of antibiotic therapy. Subsequently, toxigenic C. difficile detection rates started to fall. There was a nonsignificant increase in VRE detected in non-gastrointestinal tract samples to 8.9% in the COVID-19 group, as compared to 5.3% in the control group. Molecular analysis confirmed mainly clonal spread of VRE. Full article