Spread of ampicillin/vancomycin-resistant Enterococcus faecium of the epidemic-virulent clonal complex-17 carrying the genes esp and hyl in German hospitals

Abstract

The incidence of vancomycin-resistant Enterococcus faecium isolation was low (<or=5%) in German hospitals before 2003. Within the second half of 2003 and the first half of 2004, however, increasing frequencies of up to 14% were noticed in several hospitals in southwestern Germany. This increase was attributed mainly to the occurrence and spread of epidemic-virulent ampicillin/vancomycin-resistant, vanA- and vanB-positive E. faecium clones, most of which exhibited the virulence factors enterococcal surface protein (esp) and bacteriocin activity and some which exhibited hyaluronidase (hyl). E. faecium possessing hyaluronidase was initially found in U.S. hospitals and recently detected in several European hospitals and, subsequently, in German hospitals as well. Ampicillin/vancomycin-resistant E. faecium clones originating mainly from southwestern German hospitals were characterized by multilocus sequence typing since different sequence types (STs) belonging to the clonal complex-17 are currently disseminated worldwide. Multilocus sequence typing revealed that, in 1998 and 1999, ampicillin/vancomycin-resistant E. faecium clone ST-117 was prevalent in various German hospitals, while in 2003 and 2004, clone ST-203 dominated in several hospitals located in southwestern Germany. Both sequence types display single-locus variants of ST-78, which was frequently recorded in various Italian hospitals between 2000 and 2003, and all of these STs belong to the clonal complex-17. Expression of linezolid resistance was observed in ampicillin/glycopeptide-resistant E. faecium strains (VanA type) from two tertiary hospitals in southwestern Germany due to mutations in domain V of the 23S rDNA (G2576T). While in one hospital the resistance emerged during linezolid therapy, in the other hospital resistance was caused by transfer of an identical linezolid/ampicillin/glycopeptide-resistant E. faecium strain. In conclusion, it is very important to monitor the occurrence of epidemic-virulent clonal complex-17 strains of E. faecium to prevent their spread in hospitals, especially if they are resistant to glycopeptides and linezolid.

Current Trends of Emergence and Spread of Vancomycin-Resistant Enterococci

“…Retrospective epidemiological analyses in hospitals experiencing larger VRE outbreaks revealed that changes in specific procedures such as antibiotic policy, staffing, infection prevention and control regimes were, in some instances, significantly associated with increasing VRE rates, whereas in other settings this could not be shown. Increased VRE prevalence is partly associated with spread of single, distinct epidemic clones or types (Klare et al, 2005;Top et al, 2007;Bonora et al, 2007;Werner et al, 2007c;Valdezate et al, 2009;Zhu et al, 2010;Johnson et al, 2010;Hsieh et al, 2010). In contrast, VRE outbreaks in single centres tend to be polyclonal suggesting a diverse population of hospital-acquired E. faecium strains and a highly mobile resistance determinant capable of spreading widely among suitable recipient strains (Yoo et al, 2006;Deplano et al, 2007;Kawalec et al, 2007;Borgmann et al, 2007;Werner et al, 2007c;Hsieh et al, 2009).…”

Performance of three chromogenic VRE screening agars, two Etest® vancomycin protocols, and different microdilution methods in detecting vanB genotype Enterococcus faecium with varying vancomycin MICs

“…Diagnostic and university laboratories send strains to us for (vancomycin/teicoplanin) resistance confirmation and molecular typing. Our enterococcal strain collection currently contains > 10,000 isolates, mainly from hospital surveillance and infections, but also from animals, food products, the environment, and stool colonisations in outpatients (Klare et al, 1995a, Klare et al, 1995b, Klare et al, 1999, Klare et al, 2005, Werner et al, 2007, Werner et al, 2010and Werner et al, 2011a. Until now, we collected and identified 1060 vanB strains including 982 vanB-positive E. faecium and 74 vanB-positive E. faecalis which were all from hospital patients.…”

Vancomycin-Resistant Enterococci Outbreak, Germany, and Calculation of Outbreak Start

“…Although some hospitals have reported only sporadic fi ndings, others have been faced with extended outbreaks (2)(3)(4)(5). Apart from threatening patient health, these pathogens have an unfavorable economic impact on resources for healthcare in general.…”

“…Apparently, this did not jeopardize the usefulness of the outbreak alert method we used. Second, other hospitals in the region also had reports about clusters of VRE (5). Therefore, hygienic measures may also have been hampered by admission of some colonized patients from outside the hospital (9).…”