Linezolid-resistant E. faecium isolated from an open joint fracture: A report of the first isolate from Italy?

Thirty years of VRE in Germany - "expect the unexpected": The view from the National Reference Centre for Staphylococci and Enterococci

Enterococci are commensals of the intestinal tract of many animals and humans. Of the various known and still unnamed new enterococcal species, only isolates of Enterococcus faecium and Enterococcus faecalis have received increased medical and public health attention. According to textbook knowledge, the majority of infections are caused by E. faecalis. In recent decades, the number of enterococcal infections has increased, with the increase being exclusively associated with a rising number of nosocomial E. faecium infections. This increase has been accompanied by the dissemination of certain hospital-acquired strain variants and an alarming progress in the development of antibiotic resistance namely vancomycin resistance. With this review we focus on a description of the specific situation of vancomycin resistance among clinical E. faecium isolates in Germany over the past 30 years. The present review describes three VRE episodes in Germany, each of which is framed by the beginning and end of the respective decade. The first episode is specified by the first appearance of VRE in 1990 and a country-wide spread of specific vanA-type VRE strains (ST117/CT24) until the late 1990s. The second decade was initially marked by regional clusters and VRE outbreaks in hospitals in South-Western Germany in 2004 and 2005, mainly caused by vanA-type VRE of ST203. Against the background of a certain "basic level" of VRE prevalence throughout Germany, an early shift from the vanA genotype to the vanB genotype in clinical isolates already occurred at the end of the 2000s without much notice. With the beginning of the third decade in 2010, VRE rates in Germany have permanently increased, first in some federal states and soon after country-wide. Besides an increase in VRE prevalence, this decade was marked by a sharp increase in vanB-type resistance and a dominance of a few, novel strain variants like ST192 and later on ST117 (CT71, CT469) and ST80 (CT1065). The largest VRE outbreak, which involved about 2,900 patients and lasted over three years, was caused by a novel and until that time, unknown strain type of ST80/CT1013 (vanB). Across all periods, VRE outbreaks were mainly oligoclonal and strain types varied over space (hospital wards) and time. The spread of VRE strains obviously respects political borders; for instance, both vancomycin-variable enterococci which were highly prevalent in Denmark and ST796 VRE which successfully disseminated in Australia and Switzerland, were still completely absent among German hospital patients, until to date.

Acquisition of antibiotic-resistant Enterococcus faecium strains during long-term hospitalization and fast adaptation of enterococcal flora to antibiotic treatment: a case report

Recently, it has been suspected that long durations of hospitalization might be a possible risk factor to get colonized by multiple VRE strains. Here we present the case of a patient who underwent stem cell transplantation and subsequently stayed at the hospital for about 4 months until death. At least four different Enterococcus faecium strains were identified from routinely taken microbiological specimens as demonstrated by pulsed-field gel-electrophoresis. Additionally, these strains showed variable susceptibility to quinupristine/dalfopristine, vancomycin, and/or linezolid depending on different antibiotic administrations. These findings indicate that patients might be colonized with multiple Enterococcus faecium strains and that the enterococcal flora quickly adapts due to antibiotic exposure.

Emergence of increasing linezolid-resistance in enterococci in a post-outbreak situation with vancomycin-resistant Enterococcus faecium

During 2004 and at the start of 2005 a university hospital in Southwest Germany was affected by an extensive outbreak of vancomycin-resistant Enterococcus faecium (VRE). Although the outbreak was contained, linezolid-resistant enterococci emerged during and after the outbreak as the usage of linezolid became more common. Linezolid resistance was no longer limited to VRE. Nosocomial spread of linezolid-resistant but vancomycin-susceptible E. faecium was detected and these strains also emerged in patients without prior drug exposure. Linezolid should therefore be used with caution and the susceptibility of isolates monitored over time. Isolation precautions and screening of contacts should be considered to avoid spread of resistant isolates.