Vancomycin-resistant enterococcal infections: epidemiology, clinical manifestations, and optimal management

Abstract

Since its discovery in England and France in 1986, vancomycin-resistant Enterococcus has increasingly become a major nosocomial pathogen worldwide. Enterococci are prolific colonizers, with tremendous genome plasticity and a propensity for persistence in hospital environments, allowing for increased transmission and the dissemination of resistance elements. Infections typically present in immunosuppressed patients who have received multiple courses of antibiotics in the past. Virulence is variable, and typical clinical manifestations include bacteremia, endocarditis, intra-abdominal and pelvic infections, urinary tract infections, skin and skin structure infections, and, rarely, central nervous system infections. As enterococci are common colonizers, careful consideration is needed before initiating targeted therapy, and source control is first priority. Current treatment options including linezolid, daptomycin, quinupristin/dalfopristin, and tigecycline have shown favorable activity against various vancomycin-resistant Enterococcus infections, but there is a lack of randomized controlled trials assessing their efficacy. Clearer distinctions in preferred therapies can be made based on adverse effects, drug interactions, and pharmacokinetic profiles. Although combination therapies and newer agents such as tedizolid, telavancin, dalbavancin, and oritavancin hold promise for the future treatment of vancomycin-resistant Enterococcus infections, further studies are needed to assess their possible clinical impact, especially in the treatment of serious infections.

Antibacterial Resistance in Patients With Hematopoietic Stem Cell Transplantation

“…In the US, enterococci are the second most common bacteria isolated from catheter-related (CR)-BSIs 52,105. Enterococci are intrinsically resistant to many antimicrobials, but also easily acquire mutations and exogenous genes to develop further resistance 52,106. While aminopenicillin resistance is rare in E. faecalis , it is encountered around 90% of nosocomial E. faecium isolates 52,100,106.…”

“…Enterococci are intrinsically resistant to many antimicrobials, but also easily acquire mutations and exogenous genes to develop further resistance 52,106. While aminopenicillin resistance is rare in E. faecalis , it is encountered around 90% of nosocomial E. faecium isolates 52,100,106. Beta-lactamase production is infrequently associated with resistance and can be overcome with the use of beta-lactamase inhibitor compounds.…”

“…Beta-lactamase production is infrequently associated with resistance and can be overcome with the use of beta-lactamase inhibitor compounds. The production of PBP5 with low affinity to penicillins is the major culprit for beta-lactam resistance 52,106. High-level resistance to all aminoglycosides eliminates the synergistic activity of penicillins and vancomycin both of which can enhance activity of aminoglycosides in enterococci with low-to-moderate resistance.…”

“…Glycopeptide resistance in enterococci is a much bigger problem in the US than in Europe and elsewhere. By 2007, >80% of E. faecium isolates in the US hospitals were reported to be resistant to vancomycin whereas in Europe only Ireland reported a resistance rate of >50% 52,100,106,107. Similarly, MDR enterococci is much more prevalent in the US 52,106.…”

“…By 2007, >80% of E. faecium isolates in the US hospitals were reported to be resistant to vancomycin whereas in Europe only Ireland reported a resistance rate of >50% 52,100,106,107. Similarly, MDR enterococci is much more prevalent in the US 52,106. Enterococci are the third most frequent agents of bacteraemia in haematological cancer patients and HSCT recipients and may affect up to 12% of all transplant patients.…”