Molecular characterization of vancomycin-resistant Enterococcus faecium isolates from two German hospitals

Area of Science:

• Microbiology
• Epidemiology
• Infectious Diseases

Background:

• Vancomycin-resistant Enterococcus faecium (VRE) poses a significant therapeutic challenge, accounting for 10-23% of nosocomial infections.
• Glycopeptide antibiotic resistance in VRE is primarily mediated by van genes, with vanB-type being most prevalent in Germany.
• Limited data exists on the molecular epidemiology of vanB-type VRE in Germany.

Purpose of the Study:

• To conduct molecular epidemiological typing of vanB-type VRE isolates from two German hospitals.
• To investigate the genetic relatedness and transmission patterns of VRE in Essen and Nuremberg.
• To analyze 128 VRE isolates collected between 2011-2012 and 2017-2018.

Main Methods:

• Multilocus sequence typing (MLST) was employed to determine sequence types (STs).
• Pulsed-field gel electrophoresis (PFGE) was used to assess genetic diversity and outbreak investigation.
• Isolates were collected from two hospitals in Essen and Nuremberg.

Main Results:

• Sequence type 117 (ST 117) was the predominant ST, particularly after 2017.
• PFGE analysis revealed 68 distinct PFGE types, indicating broad genetic diversity among vanB VRE.
• Two suspected in-hospital outbreaks were confirmed, but overall in-hospital transmissions were infrequent.

Conclusions:

• MLST results align with previous findings on ST distribution in Germany.
• PFGE demonstrated significant genetic diversity of vanB VRE within and between the studied hospitals.
• While in-hospital transmissions are rare, the occurrence of outbreaks underscores the need for targeted patient screening and isolation during transmission events to identify common sources or hygiene issues.