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Unit 13: Nosocomial Pathogens and Antibiotic Resistances

Guido Werner
Franziska Layer

We are primarily concerned with surveying and studying the emergence and spread of those bacterial nosocomial pathogens that can act as indicators of hospital hygiene efficacy and rational antibacterial chemotherapy. Although our work primarily focusses on aspects of MRSA and VRE, further analyses and studies of gram-negative bacteria (E.coli, Klebsiella spp., and others) with production of extended spectrum beta-lactamases (ESBL) and carbapenemases are also addressed in our group.

Of particular interest is the spread and evolution of newly emerging resistance characteristics, of multiresistant strains and of epidemic strain variants. Our studies are based on population-wide analysis of successful clonal lineages and on the identification of genetic determinants for antibiotic resistance and pathogenicity. In addition, we have targeted projects aimed at evaluating advanced diagnostic and typing methodologies. Since decades we serve the "One-health" approach by participating or coordinating various interdisciplinary research projects to identify and quantify agricultural and environmental reservoirs of antibiotic resistance.

Scientists of our unit are active members in various national and international societies and their corresponding working and study groups (German Society for Hygiene and Microbiology (DGHM), the Paul-Ehrlich Society (PEG), the European Society for Clinical Microbiology and Infectious Diseases (ESCMID)) and represent the institute at distinct national and international commissions and institutions, such as at the European Centre for Disease Prevention and Control (ECDC).

Scientists of our unit give lectures and are actively involved in students’ education at universities in neighbouring cities (Braunschweig, Magdeburg, Göttingen, Hanover). Regularly, bachelor, master and PhD students perform their experimental work as part of their studies in our laboratories and under supervision of our scientists.

The unit hosts the German National Reference Centre for Staphylococci and Enterococci.


  • Tracing the emergence and spread of bacterial pathogens (Staphylococcus spp., Enterococcus spp., Enterobacteriaceae) and their characteristic determinants (antibiotic resistance, pathogenicity)
  • Deducing important markers for successful and prevalent bacterial strain types
  • Analysing nosocomial staphylococcal, enterococcal and enterobacterial isolates based on various typing methods
  • evaluating diagnostic and typing assays based on a representative set of staphylococcal, enterococcal and enterobacterial reference and type strains
  • Supporting regulatory bodies and commissions in establishing recommendations for infection prevention and control regarding nosocomial pathogens (KRINKO)

Date: 17.02.2020

National Reference Centre for Staphylococci and Enterococci

Guido Werner
Franziska Layer

Our main focus is the epidemiological surveillance of staphylococcal infections in hospitals and the community as well as of emerging and disseminating staphylococcal strains with special resistance and virulence traits (Hospital associated HA-MRSA, community-associated CA-MRSA, livestock-associated LA-MRSA).

The reference centre provides a typing service to support the analysis of nosocomial infections in a network of bacteriological laboratories at university hospitals, general hospitals, public health institutions and private diagnostic laboratories. Furthermore prospective clinical studies are supported and performed in collaboration with clinical partners. The reference centre is further involved in the evaluation of new methods of staphylococcal and enterococcal diagnostics and typing. We analyse, characterize and type approximately 4000 staphylococci (mainly MRSA) and 1000 enterococci (mainly VRE) per year. The reference centre collaborates closely with other reference laboratories mainly in Europe.

Date: 17.02.2020


  • Mischnik A, Werner G, Bender JK, Mutters NT (2019): Enterokokken mit speziellen Resistenzen – Epidemiologie, Hygiene und Therapie.
    Dtsch. Med. Wochenschr. 144 (8): 553–560. Epub Apr 15. doi: 10.1055/a-0655-6454. more

  • Bender JK, Fleige C, Klare I, Werner G (2019): Development of a multiplex-PCR to simultaneously detect acquired linezolid resistance genes cfr, optrA and poxtA in enterococci of clinical origin.
    J. Microbiol. Methods 160 (May): 101–103. Epub Mar 30. doi: 10.1016/j.mimet.2019.03.025. more

  • Klare I, Bender JK, Fleige C, Kriebel N, Hamprecht A, Gatermann S, Werner G (2019): Comparison of VITEK® 2, three different gradient strip tests and broth microdilution for detecting vanB-positive Enterococcus faecium isolates with low vancomycin MICs.
    J. Antimicrob. Chemother. 74 (10): 2926-2929. Epub Jul 23. doi: 10.1093/jac/dkz310. more

  • Layer F, Vourli S, Karavasilis V, Strommenger B, Dafopoulou K, Tsakris A, Werner G, Pournaras S (2018): Dissemination of linezolid-dependent, linezolid-resistant Staphylococcus epidermidis clinical isolates belonging to CC5 in German hospitals
    J. Antimicrob. Chemother. 73 (5): 1181-1184. Epub Jan 19. doi: 10.1093/jac/dkx524. more

  • Kriegeskorte A, Idelevich EA, Schlattmann A, Layer F, Strommenger B, Denis O, Paterson GK, Holmes MA, Werner G, Becker K (2017): Comparison of different phenotypic approaches to screen and detect mecC-harboring methicillin-resistant Staphylococcus aureus
    J. Clin. Microbiol.: Epub Oct 4. doi: 10.1128/JCM.00826-17. more

  • Weber RE, Layer F, Klare I, Werner G, Strommenger B (2017): Comparative evaluation of VITEK® 2 and three commercial gradient strip assays for daptomycin susceptibility testing of Staphylococcus aureus
    J. Antimicrob. Chemother. 72 (11): 3059–3062. Epub Aug 7. doi: 10.1093/jac/dkx255. more

Participation in current research activities

  • BMG-funded project GÜCCI
  • EU-funded project COMPARE
  • BMBF-funded project IRMRESS/InfectControl2020
  • BMBF-funded project MedVetStaph
  • BMBF-funded project RESET
  • BMG-funded project on genome-based phylogeny and contact-network analysis of Klebsiella pneumoniae (IIA5-2513NIK006//321-4471-02/129)
    The project aims at quantifying the benefit of a combined epidemiological, modelling and whole-genome based approach in real-time analyses of outbreaks caused by carbapenemase-producing Klebsiella penumoniae isolates. We collaborate with Units FG37 and P4 of the RKI and the National Reference Centre for multiresistant Gram-negative bacteria, Bochum, Germany.
  • BMG-funded project on Transmission dynamics of nosocomial pathogens (IIA5-2512-FSB-726)
    The project aims at identifying factors other than antibiotic usage influencing emergence and transmission dynamics of multiresistant pathogens at German Intensive Care Units. We collaborate with the University Hospital Charité, Berlin and the National Reference Centre for multiresistant Gram-negative bacteria, Bochum, Germany.
  • BMG-funded project on the Introduction of multiresistant pathogens into hospitals
    The project aims at quantifying the introduction of multiresistant pathogens into German hospitals and Intensive Care Units. We collaborate with the University Hospital Charité, Berlin, and the National Reference Centre for multiresistant Gram-negative bacteria, Bochum, Germany.
  • BMG-funded Network project of National Reference Laboratories (with focus on antibiotic resistance)
    The project aims at analysing the benefit of whole-genome analysis in a network of clinical, public health and reference laboratories in real-time surveillance and outbreak situations. We collaborate with the University Hospital Homburg, the National Reference Centre for multiresistant Gram-negative bacteria, Bochum, Unit FG37, RKI, and the Federal Public Health Laboratory Saarland, Germany.