Lutz T Zabel

Publications of Lutz T Zabel

• Antibacterial activity of human defensins on anaerobic intestinal bacterial species: a major role of HBD-3.

  Authors: Sabine Nuding, Lutz T Zabel, Corinne Enders, Edith Porter, Klaus Fellermann, Jan Wehkamp, Holger A G Mueller, Eduard F Stange

  Microbes and infection / Institut Pasteur. 02/2009;

  Defensins are natural mucosal antimicrobial peptides and their broad spectrum activity against aerobic or facultative anaerobic bacteria has been well investigated. The aim of this study was toDefensins are natural mucosal antimicrobial peptides and their broad spectrum activity against aerobic or facultative anaerobic bacteria has been well investigated. The aim of this study was to systematically examine the antibacterial activity of the small intestinal Paneth cell-derived a-defensin HD5 and the major colonic beta-defensins HBD-1 - 3 against strict anaerobic intestinal bacteria. The antibacterial activity was assessed with a flow cytometric assay employing a membrane potential sensitive dye as marker for loss of cell viability. The majority of the tested strains belonging to the dominant anaerobe genera of the gut, Bacteroides and Parabacteroides, were only minimally affected by the constitutively expressed defensins HD5 and HBD1. The inducible defensin HBD-2 had a limited antibacterial effect, whereas the inducible HBD-3 exhibited potent activity against most strains. The effect of HBD-3 on Bacteroides sp. appeared to be dependent on the presence of oxygen. Bacteroides fragilis strains isolated from blood during bacteraemia or from extraintestinal infections were more resistant to HBD-3 than strains from the physiological gut flora. Thus, defensin resistance is not only species but also strain specific and may be clinically relevant in the host-bacterial interaction influencing mucosal translocation and systemic infection.

• Two episodes of vancomycin-resistant Enterococcus faecium outbreaks caused by two genetically different clones in a newborn intensive care unit.

  Authors: Stefan Borgmann, Doris Maria Niklas, Ingo Klare, Lutz T Zabel, Peter Buchenau, Ingo B Autenrieth, Peter Heeg

  International journal of hygiene and environmental health. 10/2004; 207(4):386-9.

  In 2001 two outbreak episodes (January-March and June-July) caused by vancomycin-resistant E. faecium (VRE) of the VanA-type were observed at a neonatal intensive care unit (NICU) of a universityIn 2001 two outbreak episodes (January-March and June-July) caused by vancomycin-resistant E. faecium (VRE) of the VanA-type were observed at a neonatal intensive care unit (NICU) of a university hospital in south-west Germany. To identify the initial source and the route of transmission environmental samples were examined as well as stool samples from patients and the staff. VRE was not found in environmental samples. However, stool samples from 24 hospitalised children tested positive and bacterial clonality was assessed by Sma1-based macro restriction analysis. Furthermore, esp gene and vancomycin resistance gene carriage were examined as well as bacteriocin production. PCR analysis showed that all 24 isolates carried vanA gene cluster, encoding resistance to vancomycin and teicoplanin. However, five of the vanA-positive isolates were resistant to vancomycin but not to teicoplanin. Only these five isolates produced bacteriocin, but in none of the isolates esp gene was detected. PFGE revealed that both outbreaks were caused by two different clones. The patient initiating the first episode, was identified whereas the origin of the second episode remained unknown. From one of the 40 staff stool samples VRE was isolated. This strain was related to the clone of the summer outbreak. In conclusion there were two independent episodes of self limiting VRE outbreaks and transmission on the ward is highly probable.

• Antibacterial activity of human defensins on anaerobic intestinal bacterial species: a major role of HBD-3

  Authors: Sabine Nuding, Lutz T. Zabel, Corinne Enders, Edith Porter, Klaus Fellermann, Jan Wehkamp, Holger A.G. Mueller, Eduard F. Stange

  Microbes and Infection.

  Defensins are natural mucosal antimicrobial peptides and their broad spectrum activity against aerobic or facultative anaerobic bacteria has been well investigated. The aim of this study was toDefensins are natural mucosal antimicrobial peptides and their broad spectrum activity against aerobic or facultative anaerobic bacteria has been well investigated. The aim of this study was to systematically examine the antibacterial activity of the small intestinal Paneth cell derived α-defensin HD5 and the major colonic β-defensins HBD-1–3 against strict anaerobic intestinal bacteria. The antibacterial activity was assessed with a flow cytometric assay employing a membrane potential sensitive dye as marker for loss of cell viability. The majority of the tested strains belonging to the dominant anaerobe genera of the gut, Bacteroides and Parabacteroides, were only minimally affected by the constitutively expressed defensins HD5 and HBD-1. The inducible defensin HBD-2 had a limited antibacterial effect, whereas the inducible HBD-3 exhibited potent activity against most strains. The effect of HBD-3 on Bacteroides sp. appeared to be dependent on the presence of oxygen. Bacteroides fragilis strains isolated from blood during bacteremia or from extraintestinal infections were more resistant to HBD-3 than strains from the physiological gut flora. Thus, defensin resistance is not only species- but also strain-specific and may be clinically relevant in the host–bacteria interaction influencing mucosal translocation and systemic infection.