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AG Seifert
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AG Seifert

Group Leader: Prof. Dr. Harald Seifert
Phone: +49 221 478 32008 [Email protection active, please enable JavaScript.]

Selected recent publications (Acinetobacter baumannii)
Selected recent publications (Staphylococcus aureus)

Co-workers:

Julia Ertel, Technician (-32211/ 32231 )
Dr. Paul G. Higgins (-32011/32231/32212 [Email protection active, please enable JavaScript.] )
Danuta Stefanik, Technician (-32203 [Email protection active, please enable JavaScript.] )
Yvonne Stelzer, Technician (-32231 )
Priv.-Doz. Dr. Hilmar Wisplinghoff ( [Email protection active, please enable JavaScript.] )
Kyriaki Xanthopoulou, PhD Student (-32231 )

Research Topic:
Acinetobacter baumannii and Staphylococcus aureus

Acinetobacter baumannii
Acinetobacter baumannii is a serious and emerging nosocomial pathogen. The organism is characterised by its innate and acquired antimicrobial resistance, a propensity to cause outbreaks, an ability to survive desiccation (unlike most other gram-negatives) and its survival on inanimate materials. These characteristics mean that once established in a hospital, A. baumannii is difficult to eradicate. A. baumannii is often grouped together with the closely-related Acinetobacter genomic species 3 and 13TU. They are collectively termed the Acinetobacter baumannii group.
Our interest in the Acinetobacter baumannii group is centred on identification and speciation, epidemiology, antimicrobial susceptibility and resistance mechanisms.

(i) For the investigation of Acinetobacter baumannii group epidemicity we evaluated and further developed molecular methods such as pulsed-field gel electrophoresis (PFGE) where we have helped establish a short PFGE protocol, multi locus sequence typing (MLST) where we were involved in establishing the A. baumannii MLST scheme, and more recently, the Diversilab semi-automated rep-PCR typing scheme.

(ii) Our investigation into resistance mechanisms has included fluoroquinolone- and carbapenem-resistance, the distribution of carbapenem-hydrolysing enzymes, identification of novel oxacillinases and the worldwide epidemiology of multi-drug resistant A. baumannii.

(iii) We are also involved in the testing of novel antimicrobial compounds such as tigecycline, finafloxacin and most recently BAL 30072 to determine their anti-Acinetobacter potential.

As part of the BMBF-funded Forschergruppe "Klinische Infectiologie" we are currently involved in a study investigating the expression of A. baumannii efflux pumps and outer membrane proteins under different physiological conditions, and the role of the two-component regulatory system AdeRS in expression of the AdeABC efflux pump system.

Other ongoing projects include the molecular epidemiology of Acinetobacter species isolated from German Hospitals and the molecular epidemiology of Acinetobacter baumannii group bloodstream isolates in the United States.

Selected recent publications (2013-date)


 

Staphylococcus aureus
In recent years bloodstream infections caused by Staphylococcus aureus have increased considerably and are a major cause of morbidity and mortality worldwide. S. aureus is responsible for about 20% of all catheter-associated bloodstream infections and for about 30% of endocarditis cases. In-hospital mortality of S. aureus bacteremia (SAB) is in the range of 20 to 30%. Furthermore, the emergence of methicillin-resistant S. aureus (MRSA) infections has substantially limited therapeutic options. The clinical course of SAB is very variable. Some patients do not show any overt signs of disease whereas other patients suffer from serious complications that may result from dissemination and metastatic infection of distant organs.

To better understand and predict the clinical course of SAB, we are conducting a prospective observational cohort study on patients with SAB at two university hospitals, Freiburg and Köln (INSTINCT – invasive Staphylococcus aureus infection cohort). In this study quality indicators (such as early removal of intravascular catheters, follow-up blood cultures, transesophageal echocardiography, ensuring adequate antimicrobial treatment) are developed to monitor and improve the management of patient with SAB. Of particular interest is the impact of an early proactive, quality indicator-based management on late complications and survival in patients with SAB. This study is part of the BMBF-funded Forschergruppe "Klinische Infektiologie".

We have been involved in a DG SANCO (Directorate General for Public Health and Consumer Protection)-funded multicenter study (BURDEN) to investigate the burden of resistance at the European level in patients with methicillin-susceptible or -resistant S. aureus bloodstream infections in different hospitals in 14 European countries.

Another multicenter pilot study (preSABATO – S. aureus bacteremia antibiotic treatment options) is coordinated by our group. This pilot study is funded by the German research foundation (DFG) and examines the feasibility of conducting large multicenter trials on antibiotic treatment schemes.

Our interest in S. aureus apart from clinical studies is centred on the molecular epidemiology and antimicrobial susceptibility of methicillin-resistant S. aureus (MRSA). We are currently conducting a study to investigate the possible occurrence of a vancomycin MIC creep among MRSA bloodstream isolates isolated between 1984 and 2010. Also, the possible impact of elevated vancomycin MICs on outcome in patients with SAB from our INSTICT cohort is currently under study.

Selected recent publications (2013-date)

Other selected recent publications (2013-date)

 

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