W Witte

Publications (134)298.42 Total impact

• Article: [Vancomycin-resistant enterococci (VRE) : Recent results and trends in development of antibiotic resistance].

  I Klare, W Witte, C Wendt, G Werner
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  ABSTRACT: Enterococci (mainly E. faecalis, E. faecium) are important nosocomial pathogens predominantly affecting older and/or immunocompromised patients. The bacteria possess a broad spectrum of intrinsic and acquired antibiotic resistance properties. Among these, the transferrable glycopeptide resistance of the vanA and vanB genotypes in vancomycin-resistant enterococci (VRE; reservoir: E. faecium) as well as resistance to last resort antibiotics (e.g. linezolid and tigecycline) are of special concern. Enterococci (including VRE) are easily transferred in hospitals; however, colonizations are far more frequent than infections. Resistance frequencies for vancomycin in clinical E. faecium isolates have remained at a relatively constant level of 8-15% (but with local or regional variations) in recent years whereas frequencies for teicoplanin resistance have shown a slight decrease. Glycopeptide resistance trends correlate with a spread of hospital-associated E. faecium strains carrying the vanA and, with rising frequency in recent years, the vanB gene cluster, the latter being associated with teicoplanin susceptibility. This increased occurrence of vanB-positive E. faecium strains may be caused by an increased use of antibiotics selecting enterococci and VRE as well as due to methodological reasons (e.g. reduced EUCAST MIC-breakpoints for glycopeptides; increased use and sensitive performance of chromogenic VRE agars, increased use of molecular diagnostic assays).
  Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 11/2012; 55(11-12):1387-400. · 0.66 Impact Factor
• Article: [Current data and trends on methicillin-resistant Staphylococcus aureus (MRSA)].

  F Layer, C Cuny, B Strommenger, G Werner, W Witte
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  ABSTRACT: Nosocomial infections caused by methicillin-resistant Staphylococcus aureus (MRSA) are a problem in hospital settings worldwide. The National Reference Centre for Staphylococci performs molecular typing on a representative sample set of MRSA isolates from German hospitals for assessing long-term trends thus following the dynamics of emergence and spread of MRSA clones. The article focuses on recent data concerning antibiotic resistance and epidemic MRSA in nosocomial settings and also reflects the impact of community-acquired MRSA and MRSA from zoonotic reservoirs. Identifying common and newly emerging clones is an on-going challenge in the changing epidemiology of MRSA and prevention of further spread needs molecular surveillance.
  Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 11/2012; 55(11-12):1377-86. · 0.66 Impact Factor
• Article: High prevalence of extended-spectrum-β-lactamase-producing Enterobacteriaceae in organic and conventional retail chicken meat, Germany.

  A Kola, C Kohler, Y Pfeifer, F Schwab, K Kühn, K Schulz, V Balau, K Breitbach, A Bast, W Witte, P Gastmeier, I Steinmetz
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  ABSTRACT: To determine the prevalence of extended-spectrum β-lactamase (ESBL) production in Enterobacteriaceae in retail chicken meat in Germany. A total of 399 chicken meat samples from nine supermarket chains, four organic food stores and one butcher's shop in two geographically distinct regions (Berlin and Greifswald) were screened for ESBL production using selective agar. Phenotypic ESBL isolates were tested for bla(TEM), bla(CTX-M) and bla(SHV) genes using PCR and DNA sequencing. Antibiotic coresistances were determined and strain typing was performed using PCR-based phylogenetic grouping and XbaI-PFGE. A total of 185 confirmed ESBL isolates were obtained from 175 samples (43.9%) from all tested sources. The majority of isolates were Escherichia coli producing ESBL types SHV-12 (n = 82), CTX-M-1 (n = 77) and TEM-52 (n = 16). No differences could be observed in the prevalence of ESBL producers between organic and conventional samples. 73.0% of the ESBL producers showed coresistance to tetracycline, 35.7% to co-trimoxazole and 7.6% to ciprofloxacin. Strain typing of selected E. coli isolates from Berlin revealed identical macrorestriction patterns for several isolates from samples taken from the same stores. This is the first comprehensive study from Germany showing a high prevalence of TEM-, CTX-M- and SHV-type ESBLs in Enterobacteriaceae isolated from retail chicken meat. The high rate of coresistance to different classes of antibiotics in the ESBL producers might reflect the common veterinary usage of these and related substances. There is an urgent need to further evaluate the role of poultry in the transmission of highly resistant ESBL-producing bacteria in humans.
  Journal of Antimicrobial Chemotherapy 08/2012; 67(11):2631-4. · 5.07 Impact Factor
• Article: Evaluation of adding a second marker to overcome Staphylococcus aureus spa typing homoplasies.

  P Basset, U Nübel, W Witte, D S Blanc
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  ABSTRACT: The utility of sequencing a second highly variable locus in addition to the spa gene (e.g., double-locus sequence typing [DLST]) was investigated to overcome limitations of a Staphylococcus aureus single-locus typing method. Although adding a second locus seemed to increase discriminatory power, it was not sufficient to definitively infer evolutionary relationships within a single multilocus sequence type (ST-5).
  Journal of clinical microbiology 01/2012; 50(4):1475-7. · 4.16 Impact Factor
• Source

  Available from: Stefan Borgmann

  Article: Recognition of Clostridium difficile PCR-ribotypes 001, 027 and 126/078 using an extended MALDI-TOF MS system.

  M Reil, M Erhard, E J Kuijper, M Kist, H Zaiss, W Witte, H Gruber, S Borgmann
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  ABSTRACT: During the last decade, Clostridium difficile infection (CDI) increased markedly inside as well as outside of hospitals. In association with the occurrence of new hypervirulent C. difficile strains, CDI became more important. Until now typing of C. difficile strains has been enabled by PCR-ribotyping. However, this method is restricted to specialized laboratories combined with high maintenance cost. Therefore, we tested MALDI-TOF mass spectrometry for typing of C. difficile to provide a fast method for surveillance of CDI. Using a standard set of 25 different C. difficile PCR ribotypes a database was made by different mass spectra recorded in the SARAMIS software (AnagnosTec, Zossen, Germany). The database was validated with 355 C. difficile strains belonging to 29 different PCR ribotypes collected prospectively from all submitted feces samples in 2009. The most frequent PCR ribotypes were type 001 (70%), 027 (4.8%) and 078/126 (4.7%). All three types were recognized by MALDI-TOF MS. We conclude that an extended MALDI-TOF system was capable to recognize specific markers for ribotypes 001, 027 and 078/126 allowing an effective identification of these strains.
  European Journal of Clinical Microbiology 04/2011; 30(11):1431-6. · 2.86 Impact Factor
• Source

  Available from: nbn-resolving.de

  Article: Emergence of CTX‐M‐15 extended‐spectrum β‐lactamase‐producing Klebsiella pneumoniae isolates in Bosnia and Herzegovina

  A. Dedeic-Ljubovic, M. Hukic, Y. Pfeifer, W. Witte, E. Padilla, I. López-Ramis, S. Albertí
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  ABSTRACT: Clin Microbiol Infect 2010; 16: 152–156AbstractFifty-seven nosocomial Klebsiella pneumoniae isolates producing extended-spectrum β-lactamases (ESBLs) were collected between February 2007 and November 2007 in different wards of the Sarajevo (Bosnia-Herzegovina) reference hospital. These isolates comprise two major epidemic pulsed-field electrophoresis-defined clones plus two minor clones. In addition to the ESBL-mediated resistance, all strains uniformly showed resistance to ciprofloxacin, gentamicin and tobramycin. The β-lactamases involved in this resistance phenotype were TEM-1, SHV-1, and CTX-M-15, as demonstrated by isoelectric focusing, PCR amplification, and sequencing. TEM-1 and CTX-M-15 β-lactamases, as well as the aminoglycoside resistance determinants, were encoded in plasmids that could be transferred to Escherichia coli by conjugation. In three of the infected patients with the predominant clone, cefoxitin resistance development (MICs >128 mg/L) was documented. The analysis of the outer membrane proteins of the cefoxitin-susceptible and cefoxitin-resistant isolates revealed that the former expressed only one of the two major porins, OmpK36, whereas in the latter, the expression of Ompk36 was altered or abolished. This is the first report of CTX-M-15-producing K. pneumoniae in Bosnia-Herzegovina. Furthermore, we document and characterize for the first time cefoxitin resistance development in CTX-M-15-producing K. pneumoniae.
  Clinical Microbiology and Infection 01/2010; 16(2):152 - 156. · 4.54 Impact Factor
• Source

  Available from: Alexander W Friedrich

  Article: Methicillin-resistant Staphylococcus aureus (MRSA): burden of disease and control challenges in Europe.

  R Köck, K Becker, B Cookson, J E van Gemert-Pijnen, S Harbarth, J Kluytmans, M Mielke, G Peters, R L Skov, M J Struelens, E Tacconelli, A Navarro Torné, W Witte, A W Friedrich
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  ABSTRACT: Methicillin-resistant Staphylococcus aureus (MRSA) isa major cause of healthcare- and community-associated infections worldwide. Within the healthcare setting alone, MRSA infections are estimated to affect more than 150,000 patients annually in the European Union (EU), resulting in attributable extra in-hospital costs of EUR 380 million for EU healthcare systems. Pan-European surveillance data on bloodstream infections show marked variability among EU Member States in the proportion of S. aureus that are methicillin-resistant, ranging from less than 1% to more than 50%. In the past five years, the MRSA bacteraemia rates have decreased significantly in 10 EU countries with higher endemic rates of MRSA infections. In addition to healthcare-associated infections, new MRSA strains have recently emerged as community and livestock-associated human pathogens in most EU Member States. The prevention and control of MRSA have therefore been identified as public health priorities in the EU. In this review, we describe the current burden of MRSA infections in healthcare and community settings across Europe and outline the main threats caused by recent changes in the epidemiology of MRSA. Thereby, we aim at identifying unmet needs of surveillance, prevention and control of MRSA in Europe.
  Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 01/2010; 15(41):19688. · 6.15 Impact Factor
• Source

  Available from: Ruud Deurenberg

  Article: Prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) among pigs on German farms and import of livestock-related MRSA into hospitals.

  R Köck, J Harlizius, N Bressan, R Laerberg, L H Wieler, W Witte, R H Deurenberg, A Voss, K Becker, A W Friedrich
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  ABSTRACT: The aim of this study was to evaluate the prevalence and molecular characteristics of methicillin-resistant Staphylococcus aureus (MRSA) among pigs and estimate the impact of this animal reservoir on human healthcare. Nasal swabs were derived from 1,600 pigs at 40 German farms. The MRSA were characterized using S. aureus protein A (spa) typing, multilocus sequence typing (MLST) and detection of toxin genes. In a retrospective case control study, we compared risk factors for the carriage of MRSA between patients carrying spa types found among regional pigs and patients with other MRSA molecular types. Pigs carrying MRSA were identified on 70% of the farms (spa types t011, t034, t108, t1451 and t2510, all associated with MLST sequence type ST398). Contact to pigs and cattle were independent risk factors for the carriage of these spa types in patients at hospital admission. Our results indicate that livestock represents a relevant reservoir for the import of MRSA into regional German hospitals.
  European Journal of Clinical Microbiology 09/2009; 28(11):1375-82. · 2.86 Impact Factor
• Source

  Available from: Marc J Struelens

  Article: Laboratory tools and strategies for methicillin-resistant Staphylococcus aureus screening, surveillance and typing: state of the art and unmet needs.

  M J Struelens, P M Hawkey, G L French, W Witte, E Tacconelli
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  ABSTRACT: The public health burden caused by methicillin-resistant Staphylococcus aureus (MRSA) infections is now widely recognized, and is a cause of public alarm. Effective MRSA risk management in the healthcare system as well as in the community should rely on accurate detection of reservoirs and sources of transmission, as well as on close monitoring of the impact of interventions on disease incidence and bacterial dissemination. MRSA carrier screening and disease surveillance, coupled with molecular typing, are key information tools for integrated MRSA control and individual risk assessment. These tools should be tailored to the distinct needs of local interventions and national prevention programmes. Surveillance schemes should primarily inform local staff and serve as quality assurance about MRSA risk management. New technologies, including the use of selective culture media and real-time PCR assays, allow faster detection of MRSA carriers upon admission or during stay in healthcare institutions. More research is needed to ascertain their cost-effectiveness for MRSA control. Likewise, tremendous progress has been made concerning molecular typing methods, with optimization and standardization of sequence-based technologies offering broad applicability and high throughput. However, no single S. aureus typing method is yet providing fully reliable information within the range of discrimination needed for public health action. Further refinement of genotyping methods and international harmonization of surveillance and typing schemes must be achieved to facilitate global MRSA control.
  Clinical Microbiology and Infection 03/2009; 15(2):112-9. · 4.54 Impact Factor
• Source

  Available from: Teresa M Coque

  Article: Emergence and spread of vancomycin resistance among enterococci in Europe.

  G Werner, T M Coque, A M Hammerum, R Hope, W Hryniewicz, A Johnson, I Klare, K G Kristinsson, R Leclercq, C H Lester, [......], C Novais, B Olsson-Liljequist, L V Peixe, E Sadowy, G S Simonsen, J Top, J Vuopio-Varkila, R J Willems, W Witte, N Woodford
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  ABSTRACT: Nowadays, six types of acquired vancomycin resistance in enterococci are known; however, only VanA and to a lesser extent VanB are widely prevalent. Various genes encode acquired vancomycin resistance and these are typically associated with mobile genetic elements which allow resistance to spread clonally and laterally. The major reservoir of acquired vancomycin resistance is Enterococcus faecium; vancomycin-resistant Enterococcus faecalis are still rare. Population analysis of E. faecium has revealed a distinct subpopulation of hospital-acquired strain types, which can be differentiated by molecular typing methods (MLVA, MLST) from human commensal and animal strains. Hospital-acquired E. faecium have additional genomic content (accessory genome) including several factors known or supposed to be virulence-associated. Acquired ampicillin resistance is a major phenotypic marker of hospital-acquired E. faecium in Europe and experience has shown that it often precedes increasing rates of VRE with a delay of several years. Several factors are known to promote VRE colonisation and transmission; however, despite having populations with similar predispositions and preconditions, rates of VRE vary all over Europe.
  Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 12/2008; 13(47). · 6.15 Impact Factor
• Article: A European laboratory network for sequence-based typing of methicillin-resistant Staphylococcus aureus (MRSA) as a communication platform between human and veterinary medicine--an update on SeqNet.org.

  A W Friedrich, W Witte, H de Lencastre, W Hryniewicz, J Scheres, H Westh
  Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 06/2008; 13(19). · 6.15 Impact Factor
• Article: [Occurrence of MRSA in pigs and in humans involved in pig production--preliminary results of a study in the northwest of Germany].

  D Meemken, C Cuny, W Witte, U Eichler, R Staudt, T Blaha
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  ABSTRACT: In 2007, 678 pigs of all age groups out of 347 different farms from Lower Saxony and Northrhine-Westphalia and 86 persons occupationally exposed to pigs were investigated for their nasal colonisation with methicillin-resistant Staphylococcus areus (MRSA) by the Field Station for Epidemiology of the University of Veterinary Medicine Hannover and the Robert Koch-Institute. At the individual animal level, a frequency of positive results of 13% (n = 85 positive animals) and at the herd level, a frequency of positive results of 18% (n = 62 positive herds) were found. All isolates were assigned to the Multilocus Sequence Typing Type ST398. Within MRSA-positive herds, there were more MRSA-negative than MRSA-positive animals. Among the occupationally exposed persons (veterinarians, laboratory personnel and meat inspection personnel), 20 persons (23%) showed a nasal colonisation with MRSA ST398. A quite strong association between the intensity of the contact to pigs with the frequency of nasal colonisation in the occupationally exposed persons was detected. None of the animals or the humans nasally colonised by MRSA ST398 showed any clinical symptoms of a staphylococcal infection. Conclusions are drawn on the herd and intra-herd prevalence of the nasal colonisation of pigs with MRSA ST398 in pigs, but especially on which questions need to be addressed by further research.
  DTW. Deutsche tierärztliche Wochenschrift 05/2008; 115(4):132-9. · 0.41 Impact Factor
• Article: Community-associated methicillin-resistant Staphylococcus aureus ST8 ("USA300") in an HIV-positive patient in Cologne, Germany, February 2008.

  W Witte, C Braulke, B Strommenger
  Euro surveillance: bulletin europeen sur les maladies transmissibles = European communicable disease bulletin 04/2008; 13(13). · 6.15 Impact Factor
• Article: spa Typing of Staphylococcus aureus as a frontline tool in epidemiological typing.

  B Strommenger, C Braulke, D Heuck, C Schmidt, B Pasemann, U Nübel, W Witte
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  ABSTRACT: We determined the value of spa typing in combination with BURP (based upon repeat pattern) grouping analysis as a frontline tool in the epidemiological typing of Staphylococcus aureus, based on a random collection of 1,459 clinical isolates sent to the German Reference Centre for Staphylococci within a 6-month period. The application was found to be helpful for the classification of isolates into the particular clonal lineages currently prevalent in Germany. Due to its major advantages because of the ease of interpretation and the exchangeability of the results, the use of spa typing greatly simplifies communication between laboratories on both the national and the international levels. Thus, it is an excellent tool for national and international surveillance of S. aureus as well as for analysis of the short-term local epidemiology. However, to overcome the limitations of the BURP grouping method in terms of typing accuracy and discriminatory power, the results of the default BURP grouping method must be interpreted with caution. Additional markers, like staphylococcal chromosomal cassette mec, lineage-specific genes, or alternative DNA polymorphisms, are indispensable. They should be selected by dependence on the clonal lineage indicated by spa typing and subsequent BURP analysis as well as on the basis of the particular question to be addressed.
  Journal of clinical microbiology 03/2008; 46(2):574-81. · 4.16 Impact Factor
• Article: Multiplex PCR for rapid detection of Staphylococcus aureus isolates suspected to represent community-acquired strains.

  B Strommenger, C Braulke, B Pasemann, C Schmidt, W Witte
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  ABSTRACT: The continuous spread of community-acquired methicillin-resistant Staphylococcus aureus (caMRSA) and the introduction of these highly virulent isolates into hospitals represent increasing threats. The timely recognition of caMRSA strains is crucial for infection control purposes. Thus, we developed a PCR-based assay for the easy and rapid determination of those caMRSA clones that currently are the most prevalent in Germany and Central Europe. This assay was able to correctly identify the majority of the isolates as caMRSA of sequence type 80 (ST80), clonal complex 1 (USA400), and ST8 (USA300). In combination with spa typing-BURP (based upon repeat pattern) analysis and resistance typing, it provides a means for the extensive characterization of suspicious isolates. Thus, this assay represents a reliable tool for monitoring the emergence and spread of different caMRSA clones. The resulting information, in combination with careful interpretation of the epidemiological records, might help to prevent the further spread of those highly virulent caMRSA clones.
  Journal of clinical microbiology 03/2008; 46(2):582-7. · 4.16 Impact Factor
• Article: Management of a large healthcare-associated outbreak of Panton-Valentine leucocidin-positive meticillin-resistant Staphylococcus aureus in Germany.

  F M E Wagenlehner, K G Naber, E Bambl, U Raab, C Wagenlehner, D Kahlau, C Höller, W Witte, W Weidner, N Lehn, S Harbarth, H-J Linde
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  ABSTRACT: We report the largest documented healthcare-associated outbreak of Panton-Valentine leucocidin-positive meticillin-resistant Staphylococcus aureus (PVL(+) MRSA) in Europe. Six index patients from three long-term care facilities (LTCFs) were screened positive for PVL(+) MRSA in 2004 on admission to a community hospital in Germany. The purpose of this prospective study was to describe the prevalence of PVL(+) MRSA in the LTCFs before and after infection control interventions. Screening for MRSA with or without PVL was performed in all three LTCFs in 2004 [453 residents, 240 healthcare workers (HCWs)] and 2005 (440 residents, 192 HCWs). Swabs from anterior nares and wounds, if applicable, were collected. Colonised residents and staff were treated with mupirocin nasal ointment and topical antiseptics, and staff were provided with hygiene education. Total MRSA carrier rate of residents and HCWs in 2004 was 11.3% (PVL(+) MRSA 9.1%, PVL(-) MRSA 2.2%). There were comparable carrier rates between residents and HCWs in each LTCF. All PVL(+) MRSA isolates were of clonal origin (MLST 22) representing a novel spa sequence type t310. A decrease in total MRSA prevalence (from 11.3 to 5.5%) and PVL(+) MRSA (from 9.1 to 3.3%) was observed in 2005. The rate of PVL(-) MRSA remained unaffected. No symptomatic skin infections were noted among residents or HCWs. In this outbreak incomplete control of PVL(+) MRSA presumably resulted from difficult and delayed detection and decolonisation of carriers, incomplete compliance with control measures and lack of enforcement by public health authorities.
  Journal of Hospital Infection 11/2007; 67(2):114-20. · 3.39 Impact Factor
• Article: Clonal distribution of superantigen genes in clinical Staphylococcus aureus isolates.

  S Holtfreter, D Grumann, M Schmudde, H T T Nguyen, P Eichler, B Strommenger, K Kopron, J Kolata, S Giedrys-Kalemba, I Steinmetz, W Witte, B M Bröker
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  ABSTRACT: Staphylococcus aureus is both a successful human commensal and a major pathogen. The elucidation of the molecular determinants of virulence, in particular assessment of the contributions of the genetic background versus those of mobile genetic elements (MGEs), has proved difficult in this variable species. To address this, we simultaneously determined the genetic backgrounds (spa typing) and the distributions of all 19 known superantigens and the exfoliative toxins A and D (multiplex PCR) as markers for MGEs. Methicillin- sensitive S. aureus strains from Pomerania, 107 nasal and 88 blood culture isolates, were investigated. All superantigen-encoding MGEs were linked more or less tightly to the genetic background. Thus, each S. aureus clonal complex was characterized by a typical repertoire of superantigen and exfoliative toxin genes. However, within each S. aureus clonal complex and even within the same spa type, virulence gene profiles varied remarkably. Therefore, virulence genes of nasal and blood culture isolates were separately compared in each clonal complex. The results indicated a role in infection for the MGE harboring the exfoliative toxin D gene. In contrast, there was no association of superantigen genes with bloodstream invasion. In summary, we show here that the simultaneous assessment of virulence gene profiles and the genetic background increases the discriminatory power of genetic investigations into the mechanisms of S. aureus pathogenesis.
  Journal of Clinical Microbiology 09/2007; 45(8):2669-80. · 4.15 Impact Factor
• Article: Detection of low-level oxacillin resistance in mecA-positive Staphylococcus aureus.

  W Witte, B Pasemann, C Cuny
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  ABSTRACT: Detection of low-level oxacillin-resistant Staphylococcus aureus is a problem that needs special attention, particularly in relation to methicillin-resistant S. aureus (MRSA) strains in the community that belong to clonal lineage ST80. This study compared different phenotypic methods for the detection of 74 low-level oxacillin-resistant S. aureus strains (oxacillin MIC <or=1 mg/L), 46 MRSA strains (oxacillin MIC >or=2 mg/L) and 117 methicillin-susceptible S. aureus strains. Determination of microbroth dilution MICs for oxacillin was wholly unsatisfactory, and gave a limited specificity for cefoxitin. The sensitivity of disk-diffusion performed according to CLSI recommendations was 92% with an oxacillin 1-microg disk, and 96% with a cefoxitin 30-microg disk; use of a 10-microg cefoxitin disk and a semi-confluent inoculum (breakpoint for resistance <18 mm zone diameter) gave a sensitivity of 97%. When disk-diffusion was performed on IsoSensitest agar with a zone diameter breakpoint for resistance of <22 mm (as recommended by the Swedish Reference Group for Antibiotics), the sensitivity was 95%.
  Clinical Microbiology and Infection 04/2007; 13(4):408-12. · 4.54 Impact Factor
• Source

  Available from: mastgrp.com

  Article: Direct detection of methicillin-resistant Staphylococcus aureus in clinical specimens by a nucleic acid-based hybridisation assay.

  M Holfelder, U Eigner, A-M Turnwald, W Witte, M Weizenegger, A Fahr
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  ABSTRACT: The occurrence of methicillin-resistant Staphylococcus aureus (MRSA) is still increasing worldwide and is associated with significant morbidity, mortality and hospital costs. Screening for MRSA plays a key role in limiting further nosocomial spread of this organism. Control measures require a rapid and sensitive test for direct detection of MRSA carriage. This study evaluated an easy-to-use PCR-hybridisation assay for the direct detection of MRSA in clinical swab specimens. In total, 508 pairs of swabs from 242 patients at risk for MRSA carriage were analysed by the standard culture method and the PCR assay. One swab was used for PCR and culture, while the second was used for culture only. Of the 508 pairs tested, 37 were positive by culture and 35 were positive by PCR. Among the 471 culture-negative specimens, 465 were negative by PCR and six were PCR-positive. The PCR assay had a sensitivity of 94.59%, a specificity of 98.73%, a positive predictive value of 85.37%, and a negative predictive value of 99.57%. The PCR-hybridisation assay enabled reliable detection of MRSA carriage in c. 4 h, thereby allowing its effective use in an MRSA control strategy.
  Clinical Microbiology and Infection 01/2007; 12(12):1163-7. · 4.54 Impact Factor
• Article: Assignment of Staphylococcus isolates to groups by spa typing, SmaI macrorestriction analysis, and multilocus sequence typing.

  B Strommenger, C Kettlitz, T Weniger, D Harmsen, A W Friedrich, W Witte
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  ABSTRACT: The implementation of the new clustering algorithm Based Upon Repeat Pattern (BURP) into the Ridom StaphType software tool enables clustering based on spa typing data for Staphylococcus aureus. We compared clustering results obtained by spa typing/BURP to those obtained by currently well-established methods, i.e., SmaI macrorestriction analysis and multilocus sequence typing/eBURST. A total of 99 clinical S. aureus strains, including MRSA and representing major clonal lineages associated with important kinds of infections which have been prevalent in Germany and Central Europe during the last 10 years, were used for comparison. SmaI macrorestriction analysis revealed the highest discriminatory power, and clustering results for all three methods resulted in concordance values ranging from 96.8% between the two sequence-based methods to 93.4% between spa typing/BURP and SmaI macrorestriction/cluster analysis. The results of this study indicate that spa typing, together with BURP clustering, is a useful tool in S. aureus epidemiology, especially because of ease of use and the advantages of unambiguous sequence analysis as well as reproducibility and exchange of typing data.
  Journal of Clinical Microbiology 08/2006; 44(7):2533-40. · 4.15 Impact Factor