K Botzenhart

University of Tuebingen, Tübingen, Baden-Wuerttemberg, Germany

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Publications (57)120.27 Total impact

  • K Botzenhart
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    ABSTRACT: Viruses in drinking water can cause infectious diseases. In the past, hepatitis A and E were the most frequently observed drinking- water-borne viral infections, but in recent years several small- and large-scale norovirus epidemics have been described, even in Europe. All virus species spread via drinking water are of fecal origin. They are regularly identified in waste water even after conventional multi-stage water treatment. The approved disinfection methods can cope with these viruses if they are not integrated in larger particles. For this reason particle separation is particularly important in water treatment. Virological tests are not reliable enough to ensure that drinking water is sufficiently virus-free. The examination of 100 mL of water for E. coli and coliform bacteria is not adequate proof either. If potentially contaminated raw water is used, consumer safety must be ensured by calculating the performance of water treatment plants on a case-by-case basis. Such a calculation takes into account the virus load of the raw water, the efficiency of the physical and chemical particle elimination steps and the effect of disinfection. Those factors which determine the effectiveness of disinfection, namely concentration and exposure time or UV radiation strength, must be adjusted according to the risk of viral infection, and calculated settings must be adhered to, even if favorable E. coli levels may make them seem excessive.
    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 04/2007; 50(3):296-301. · 1.01 Impact Factor
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    K. Botzenhart
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    ABSTRACT: Viren im Trinkwasser können Infektionskrankheiten verursachen. Während dieses früher vor allem für die Hepatitis A und der Hepatitis E beobachtet wurde, sind in den letzten Jahren mehrere größere und kleinere Epidemien von Norwalkvirusinfektionen beschrieben worden, auch in Europa. Alle trink wasserrelevanten Viren stammen aus Fäkalien und sind im Abwasser auch nach mehrstufiger konventioneller Klärung regelmäßig noch nachweisbar. Sie sind den zugelassenen Desinfektionsverfahren gut zugänglich, soweit sie nicht in größere Partikel integriert sind. Folglich kommt der Partikelabscheidung bei der Aufbereitung eine besonders große Bedeutung zu. Die Virusfreiheit des abgegebenen Trinkwassers kann mit der erforderlichen Sicherheit durch virologische Untersuchungen nicht nachgewiesen werden. Die Untersuchung von 100-mL-Proben auf E. coli und coliforme Bakterien ist dafür ebenfalls nicht aus reichend. Bei Verwendung von möglicherweise kontaminiertem Rohwasser muss daher die Sicherheit der Verbraucher über eine von Fall zu Fall zu berechnende Leistungsfähigkeit der Aufbereitungsanlage gewährleistet werden. In die Berechnung gehen die Virusbelastung des Rohwassers, die Leistung der physikalisch- chemischen Partikelelimination und die Wirkung der Desinfektion ein. Die wirkungsbestimmenden Faktoren der Desinfektion, namentlich Konzentration und Einwirkungszeit bzw. die UV-Bestrahlungsstärke, müssen anhand des Infektionsrisikos durch Viren festgelegt und eingehalten werden, auch wenn sie aufgrund günstiger E.-coli-Befunde überhöht erscheinen. Viruses in drinking water can cause infectious diseases. In the past, hepatitis A and E were the most frequently observed drinking- water-borne viral infections, but in recent years several small- and large-scale norovirus epidemics have been described, even in Europe. All virus species spread via drinking water are of fecal origin. They are regularly identified in waste water even after conventional multi-stage water treatment. The approved disinfection methods can cope with these viruses if they are not integrated in larger particles. For this reason particle separation is particularly important in water treatment. Virological tests are not reliable enough to ensure that drinking water is sufficiently virus-free. The examination of 100 mL of water for E. coli and coliform bacteria is not adequate proof either. If potentially contaminated raw water is used, consumer safety must be ensured by calculating the performance of water treatment plants on a case-by-case basis. Such a calculation takes into account the virus load of the raw water, the efficiency of the physical and chemical particle elimination steps and the effect of disinfection. Those factors which determine the effectiveness of disinfection, namely concentration and exposure time or UV radiation strength, must be adjusted according to the risk of viral infection, and calculated settings must be adhered to, even if favorable E. coli levels may make them seem excessive.
    Bundesgesundheitsblatt - Gesundheitsforschung - Gesundheitsschutz 03/2007; 50(3):296-301. DOI:10.1007/s00103-007-0155-4 · 1.01 Impact Factor
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    ABSTRACT: We performed epidemiologic studies at public freshwater bathing sites in Germany to provide a better scientific basis for the definition of recreational water quality standards. A total of 2,196 participants were recruited from the local population and randomized into bathers and nonbathers. Bathers were exposed for 10 min and had to immerse their head at least three times. Water samples for microbiological analysis were collected at 20-min intervals. Unbiased concentration-response effects with no-observed-adverse-effect levels (NOAELs) were demonstrated for three different definitions of gastroenteritis and four fecal indicator organisms. Relative risks for bathing in waters with levels above NOAELs compared with nonbathing ranged from 1.8 (95% CI, 1.2-2.6) to 4.6 (95% CI, 2.1-10.1), depending on the definition of gastroenteritis. The effect of swallowing water provided additional evidence for true dose-response relationships. Based on the NOAELs, the following guide values for water quality are suggested: 100 Escherichia coli, 25 intestinal enterococci, 10 somatic coliphages, or 10 Clostridium perfringens per 100 mL. Recreational water quality standards are intended to protect the health of those consumers who are not already immune or resistant to pathogens that may be associated with indicator organisms. In contrast to current World Health Organization recommendations, we concluded that standards should be based on rates of compliance with NOAELs rather than on attributable risks determined above NOAELs, because these risks depend mainly on the unpredictable susceptibility of the cohorts. Although in theory there is no threshold in real concentration-response relationships, we demonstrated that a NOAEL approach would be a more robust and practical solution to the complex problem of setting standards.
    Environmental Health Perspectives 03/2006; 114(2):228-36. DOI:10.1289/ehp.8115 · 7.98 Impact Factor
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    Renata Filkorn-Kaiser · Konrad Botzenhart · Albrecht Wiedenmann
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    ABSTRACT: A recently described quantitative rapid cycle real time PCR (LightCycler) assay detects Cryptosporidium parvum after in vitro excystation, which is a surrogate marker for the viability of the organisms. In the original assay the quantification standard is a dilution series of C. parvum oocysts with a microscopically determined excystation rate. The need to keep suspensions of viable oocysts in stock and to continuously monitor their excystation rate, however, renders the assay impracticable for routine application. A synthetic standard was developed to replace the in vivo standard and was calibrated using oocysts with known excystation rates. The standard consists of a 486 bp DNA segment ranging from 229 bp upstream to 79 bp downstream of the actual PCR target site. Aliquots of the standard were frozen and stored at -20 degrees C and at -70 degrees C or lyophilised and stored at room temperature in the dark. For a period of one year samples preserved with each of the three methods were restored every four or five weeks. They were amplified in the LightCycler and the crossing points (CP) were monitored. No significant trend in the raw CP values could be observed for any of the three storage methods. However, when the methods were compared to each other by calculating the CP ratios (-20 degrees C/-70 degrees C; -20 degrees C/lyophilised; -70 degrees C/lyophilised) at the 10 monitoring dates, the CP ratios -20 degrees C/-70 degrees C and -20 degrees C/lyophilised showed a highly significant positive trend (p < 0.0001) while the CP ratio -70 degrees C/lyophilised did not differ from the null hypothesis (p = 0.53). It can be concluded that the latter two preservation methods are both appropriate, while storage at -20 degrees C is less advisable. Calculations based on the molecular weight of the standard and on the assumption of an average yield of three sporozoites per oocyst led to the conclusion that the target sequence is probably located on a double copy gene.
    Journal of Water and Health 03/2005; 3(1):15-25. · 1.46 Impact Factor
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    ABSTRACT: The influence of the DNA extraction method on the sensitivity and specificity of bacteraemia detection by a 16S rRNA gene PCR assay was investigated. The detection limit of the assay was 5 fg with purified DNA from Escherichia coli or Staphylococcus aureus, corresponding to one bacterial cell. However, with spiked blood samples, the detection limits were 10(4) and 10(6) CFU/mL, respectively. The sensitivity of the S. aureus assay was improved to the level of the E. coli test with the addition of proteinase K to the commercial DNA extraction kit protocol. Ten (16.6%) of 60 amplification reactions were positive with templates isolated from sterile blood, while PCR reagent controls were negative, thereby indicating contamination during the DNA extraction process. Blood samples were spiked with serial dilutions of E. coli and S. aureus cells, and six PCR results were obtained from three extractions for each blood sample. A classification threshold system was devised, based on the number of positive reactions for each sample. Samples were deemed positive if at least four positive reactions were recorded, making it possible to avoid false-positive results caused by contamination. These results indicate that a comprehensive validation procedure covering all aspects of the assay, including DNA extraction, can improve considerably the validity of PCR assays for bacteraemia, and is a prerequisite for the meaningful detection of bacteraemia by PCR in the clinical setting.
    Clinical Microbiology and Infection 06/2004; 10(5):452-8. DOI:10.1111/j.1469-0691.2004.00877.x · 5.20 Impact Factor
  • Qiang Fang · Stefan Brockmann · Konrad Botzenhart · Albrecht Wiedenmann
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    ABSTRACT: This report describes a new technique for the detection and identification of Salmonella species in food with the use of fluorescent in situ hybridization (FISH) with 23S rRNA-targeted oligonucleotide probes. Two species-specific 23S rRNA-targeted oligonucleotide probes (Sal-1 and Sal-3) were selected, and one (Sal-544) was newly designed. The relative specificities of these probes were compared with those of bacterial 23S rRNA sequences from the GenBank database and tested by in situ hybridization with bacterial cell smears of pure cultures. Fifty-one tested reference strains of Salmonella serovars belonging to subspecies I (enterica) hybridized with these probes. No cross-reactions with 46 other strains of the family Enterobacteriaceae or with another 14 bacterial strains from other families were observed. Storage of a Salmonella Panama test strain under various environmental conditions (2, 5, and 15% NaC1; -20 degrees C, 4 degrees C, and room temperature; pHs of 3.3 to 7.4) did not adversely affect the FISH method. No matrix effects were observed with 18 different kinds of foods. FISH was able to detect Salmonella spp. in 52 (probe Sal-1), 56 (probe Sal-3), and 35 (probe Sal-544) of 225 naturally contaminated food samples after 16 h of incubation in a preenrichment broth. When conventional culture and detection methods were used, Salmonella could be isolated from only 30 of these 225 samples. In contrast, FISH failed to identify Salmonella in only two of the culture-positive samples when Sal-1 and Sal-3 were used and in only three of the culture-positive samples when Sal-544 was used.
    Journal of food protection 06/2003; 66(5):723-31. · 1.80 Impact Factor
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    ABSTRACT: DNase I pretreatment of 16S rRNA gene PCR reagents was tested. The DNase I requirement for the elimination of false-positive results varied between 0.1 and 70 IU per master mix depending on the applied Taq polymerase. PCR sensitivity was mostly maintained when 0.1 IU of DNase I was used.
    Journal of Clinical Microbiology 05/2003; 41(4):1763-5. DOI:10.1128/JCM.41.4.1763-1765.2003 · 4.23 Impact Factor
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    ABSTRACT: Current theories of CF pathogenesis predict different predisposing "local environmental" conditions and sites of bacterial infection within CF airways. Here we show that, in CF patients with established lung disease, Pseudomonas aeruginosa was located within hypoxic mucopurulent masses in airway lumens. In vitro studies revealed that CF-specific increases in epithelial O(2) consumption, linked to increased airway surface liquid (ASL) volume absorption and mucus stasis, generated steep hypoxic gradients within thickened mucus on CF epithelial surfaces prior to infection. Motile P. aeruginosa deposited on CF airway surfaces penetrated into hypoxic mucus zones and responded to this environment with increased alginate production. With P. aeruginosa growth in oxygen restricted environments, local hypoxia was exacerbated and frank anaerobiosis, as detected in vivo, resulted. These studies indicate that novel therapies for CF include removal of hypoxic mucus plaques and antibiotics effective against P. aeruginosa adapted to anaerobic environments.
    Journal of Clinical Investigation 03/2002; 109(3):317-25. DOI:10.1172/JCI13870 · 13.77 Impact Factor
  • Albrecht Wiedenmann · Walter Langhammer · Konrad Botzenhart
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    ABSTRACT: We examined samples from the showers and the central water distribution system of a public building with an indoor swimming pool. The pool was used for school and recreational activities and as a sports therapy facility for patients with coronary heart disease. The building's hot water system was contaminated with Legionella pneumophila. Due to the building's intricate piping system, several attempts to completely eliminate legionellae by thermal and chemical disinfection had failed, so an external sanitation company was charged with the installation of a continuous chlorination device in order to keep Legionella concentrations low. The laboratory which was contracted by the sanitation company to monitor bacteria levels after installation of the chlorination device used sampling bottles without sodium thiosulfate and repeatedly reported an absence of Legionella. However, up to 69,000 colony forming particles (CFP) of Legionella pneumophila (Lp) per litre and up to 171 CFP/ml of heterotrophic bacteria could be detected when parallel samples were collected in bottles containing sodium thiosulfate at standard concentrations. Laboratories, epidemiologists, public health officials and technical staff who may be in charge of delivering, preparing or using sterile sampling devices for the collection of environmental samples to be tested for legionellae should be aware that cultures can return false negative results if the sampling containers used to collect chlorinated drinking water or chlorinated pool water samples do not contain a neutralizing agent to instantly inactivate residual halogen biocides. False negative results may lead to a false sense of security regarding the safety of water systems or the success of disinfection measures, and may thus endanger public health or even hinder the epidemiological clarification of outbreaks.
    International Journal of Hygiene and Environmental Health 01/2002; 204(4):245-9. DOI:10.1078/1438-4639-00101 · 3.28 Impact Factor
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    ABSTRACT: PCR has proved superior to conventional blood culture for diagnosing bacteraemia in the presence of antibiotics. Nevertheless, even PCR might yield false-negative results if the template DNA were to be cleaved by serum DNAases after antibiotics had induced bacterial death. To evaluate the cleavage of bacterial template DNA by human serum DNAase I, serum samples inoculated with purified Escherichia coli DNA were incubated with increasing amounts of recombinant human DNAase (rhDNAase) and then examined by a PCR specific for E. coli. As a prerequisite of potential DNAase attack, the release of E. coli DNA after antibiotic-induced bacterial death was quantified by fluorescence microscopy and flow cytometry. Finally, the influence of rhDNAase on the PCR-based detection of antibiotic-killed E. coli in serum was assessed. The results indicated that purified E. coli DNA is remarkably stable in human serum; positive PCR results did not decrease significantly until the ratio of recombinant human DNAase I:E. coli rose to 106:1. As only 14.8-28.4% of the total E. coli DNA was released after antibiotic killing, the PCR-based detection of E. coli fell by only 10% when cefotaxime-killed E. coli were incubated with rhDNAase. It was concluded that human serum DNAases and antibiotic killing do not compromise the reliability of PCR examinations for bacteraemia.
    Journal of Medical Microbiology 04/2001; 50(3):243-8. · 2.27 Impact Factor
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    D Worlitzsch · H Kaygin · A Steinhuber · A Dalhoff · K Botzenhart · G Döring
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    ABSTRACT: In Staphylococcus aureus infection hemolysis caused by the extracellular protein alpha-toxin encoded by hla is thought to contribute significantly to its multifactorial virulence. In vitro, subinhibitory concentrations of beta-lactam antibiotics and fluoroquinolones increase the levels of hla and alpha-toxin expression, whereas aminoglycosides decrease the levels of hla and alpha-toxin expression. In the present study we investigated the effects of subinhibitory concentrations of amoxicillin, gentamicin, and moxifloxacin on hla and alpha-toxin expression and total hemolysis of S. aureus strain 8325-4, a high-level alpha-toxin producer, and its alpha-toxin-negative mutant, DU 1090, in vitro and in a rat model of chronic S. aureus infection. The levels of expression of hla and alpha-toxin and total hemolysis did not differ significantly when amoxicillin, gentamicin, or moxifloxacin was added to cultures of S. aureus strain 8325-4. In vivo, strain 8325-4 induced a significantly increased level of hemolysis in infected pouches compared to that in uninfected control pouches, but the hemolysis was reduced to control levels by treatment with doses of amoxicillin, gentamicin, or moxifloxacin that reduced bacterial numbers by 2 orders of magnitude. Additionally, the effects of subinhibitory concentrations of the three antibiotics on total hemolysis of four methicillin-resistant S. aureus and three methicillin-sensitive S. aureus (MSSA) clinical isolates were assessed in vitro. A significant increase in total hemolysis was observed for only one MSSA strain when it was treated with amoxicillin but not when it was treated with moxifloxacin or gentamicin. When purified alpha-toxin was incubated with purified human neutrophil elastase, alpha-toxin was cleaved nearly completely. The results suggest that the penicillin-induced increases in S. aureus alpha-toxin expression are strain dependent, that reduction of bacterial numbers in vivo counteracts this phenomenon effectively, and finally, that in localized S. aureus infections alpha-toxin activity is controlled by neutrophil elastase.
    Antimicrobial Agents and Chemotherapy 02/2001; 45(1):196-202. DOI:10.1128/AAC.45.1.196-202.2001 · 4.45 Impact Factor
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    ABSTRACT: The adherence of Staphylococcus aureus to human endothelial cells (EC) is probably an important step in the pathogenesis of systemic staphylococcal infections. We examined the influence of type 5 capsular polysaccharide (CP5) production, the global regulator agr, and the bacterial growth phase onS. aureus adherence to EC. Whereas S. aureusNewman showed maximal adherence to EC in the logarithmic phase of growth, an isogenic agr mutant showed maximal adherence in the stationary growth phase. S. aureus adherence to EC and CP5 expression were negatively correlated: a mutation in theagr locus diminished CP5 production and led to increased adherence. Likewise, induction of CP5 expression by addition of NaCl to the growth medium resulted in reduced staphylococcal adherence to EC.S. aureus Newman cells that adhered to EC did not express CP5. A Newman cap5O mutant was acapsular and showed significantly greater adherence to EC than the parental strain did (P < 0.005). Complementation of the cap5Omutation in trans restored CP5 expression and reduced EC adherence to a level similar to that of the parental strain. The enhanced adherence shown by the cap5O mutant was similar in magnitude to that of the agr mutant or the cap5O agr double mutant. Cells of the cap5O mutant andcap5O agr double mutant harvested from stationary-phase cultures adhered significantly better than did cells harvested in the exponential growth phase. These data are consistent with the postexponential and agr-independent expression by S. aureus of at least one putative EC adhesin, whose binding domain may be masked by CP5.
    Infection and Immunity 09/2000; 68(9). DOI:10.1128/IAI.68.9.4865-4871.2000 · 4.16 Impact Factor
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    ABSTRACT: Bacteria possess a repertoire of distinct regulatory systems promoting survival in disparate environments. Under in vitro conditions it was demonstrated for the human pathogen Staphylococcus aureus that the expression of most virulence factors is coordinated by the global regulator agr. To monitor bacterial gene regulation in the host, we developed a method for direct transcript analysis from clinical specimens. Quantification of specific transcripts was performed by competitive reverse transcription-PCR, and results were normalized against the constitutively expressed gene for gyrase (gyr). Using sputum from cystic fibrosis (CF) patients infected with S. aureus we examined the transcription of the effector molecule RNAIII of agr, of spa (protein A), generally repressed by agr, and of hla (alpha-toxin), generally activated by agr. In the CF lung RNAIII was expressed poorly, indicating an inactive agr in vivo. Despite the low level of RNAIII expression, spa was detectable only in minute amounts and an irregular transcription of hla was observed in all sputum samples. After subculturing of patient strains agr-deficient isolates and isolates with unusual expression profiles, i.e., not consistent with those obtained from prototypic strains, were observed. In conclusion, the agr activity seems to be nonessential in CF, and from the described expression pattern of spa and hla, other regulatory circuits aside from agr are postulated in vivo.
    Infection and Immunity 04/2000; 68(3):1304-11. DOI:10.1128/IAI.68.3.1304-1311.2000 · 4.16 Impact Factor
  • Jürgen Bohnert · Barbara Hübner · Konrad Botzenhart
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    ABSTRACT: The aim of this study was to rapidly identify bacteria of the family of Enterobacteriaceae using fluorescent in situ hybridization (FISH). A comparative sequence analysis was carried out and a 23S rRNA signature sequence for Enterobacteriaceae was identified. A 23S rRNA-targeted oligonucleotide probe (EBAC1790) was constructed and subsequently tested against 40 reference strains. Nearly all of the Enterobacteriaceae used in this study yielded positive results with EBAC1790, except for Edwardsiella tarda (ATCC 15947). None of the non-Enterobacteriaceae reference strains gave positive signals with the probe. The possibility of a rapid detection of Enterobacteriaceae in groundwater was demonstrated using colony hybridization.
    International Journal of Hygiene and Environmental Health 04/2000; 203(1):77-82. DOI:10.1078/S1438-4639(04)70011-5 · 3.28 Impact Factor
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    ABSTRACT: The molecular epidemiology of Staphylococcus aureus nasal commensal strains and community-acquired infecting strains was assessed by comparison of prevalence, persistence, transmission rate, and clonal distribution of S. aureus in families with and without cystic fibrosis (CF) patients. Isolates were typed by pulsed-field gel electrophoresis. CF patients without antibiotic treatment had a significantly higher nasal prevalence (66%) of S. aureus than did treated patients (29%; P<.001) or healthy controls (32%; P<.001), suggesting that persons with CF have a higher susceptibility to this organism. Strain transmission was frequent within both CF (55%) and non-CF (62%) families. After 3 and 19 months, 57% and 21%, respectively, of all persons still harbored the same S. aureus strain. Most of the isolates (78%) belonged to 8 of 38 genome types common in CF patients and in healthy persons. The predominant occurrence of a limited number of S. aureus clones within the community suggests evolutionary mechanisms for the selection of certain strains without an obvious association with disease.
    The Journal of Infectious Diseases 03/2000; 181(3):984-9. DOI:10.1086/315331 · 5.78 Impact Factor
  • K Botzenhart
    Schriftenreihe des Vereins für Wasser-, Boden- und Lufthygiene 02/2000; 108:45-52.
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    ABSTRACT: Trefoil factor family domain peptides (TFF) are thought to be involved in mucosal epithelial restitution and wound healing of the gastrointestinal tract and are up-regulated in ulceration and in a variety of solid tumours. It was hypothesized that TFFs are also expressed on mucosal surfaces of the human respiratory tract. Lung tissue, nasal polyps, and sputum samples from seven patients with cystic fibrosis (CF), two with chronic and acute bronchitis, and non-dysplastic material from two cases of bronchial adenocarcinoma were analysed for TFF expression by immunohistochemistry, immunofluorescence, western blot and RT-PCR. Expression of TFF1 and TFF3 was observed in material from all patients. TFFs were localized in goblet and ciliated cells, as well as in some submucosal cells of tracheobronchial tissues and nasal polyps from normal and CF individuals. In sputa of patients with CF and with chronic or acute bronchitis, TFF1 and TFF3 were detected by western blotting. Freshly cultivated nasal epithelial cells transcribed and secreted TFFs and mucins, whereas nasal cells cultivated for 6 weeks still expressed mucins, but not TFFs. Secreted TFFs and mucins also bound to the surface of Staphylococcus aureus in infected CF airways. In conclusion, TFF1 and TFF3 are expressed and secreted in normal and inflamed airways. The association of TFFs with bacteria may contribute to the anti-microbial mucociliary defence system.
    The Journal of Pathology 01/2000; 190(2):133-42. DOI:10.1002/(SICI)1096-9896(200002)190:2<133::AID-PATH518>3.0.CO;2-B · 7.43 Impact Factor
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    A Heininger · M Binder · S Schmidt · K Unertl · K Botzenhart · G Döring
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    ABSTRACT: Critically ill patients often develop symptoms of sepsis and therefore require microbiological tests for bacteremia that use conventional blood culture (BC) techniques. However, since these patients frequently receive early empirical antibiotic therapy before diagnostic procedures are completed, examination by BC can return false-negative results. We therefore hypothesized that PCR could improve the rate of detection of microbial pathogens over that of BC. To test this hypothesis, male Wistar rats were challenged intravenously with 10(6) CFU of Escherichia coli. Blood was then taken at several time points for detection of E. coli by BC and by PCR with E. coli-specific primers derived from the uidA gene, encoding beta-glucuronidase. In further experiments, cefotaxime (100 or 50 mg/kg of body weight) was administered intravenously to rats 10 min after E. coli challenge. Without this chemotherapy, the E. coli detection rate decreased at 15 min and at 210 min after challenge from 100% to 62% of the animals with PCR and from 100% to 54% of the animals with BC (P, >0.05). Chemotherapy decreased the E. coli detection rate at 25 min and at 55 min after challenge from 100% to 50% with PCR and from 100% to 0% with BC (P, <0.05). Thus, at clinically relevant serum antibiotic levels, PCR affords a significantly higher detection rate than BC in this rat model. The results suggest that PCR could be a useful adjunct tool supplementing conventional BC techniques in diagnosing bacteremia.
    Journal of Clinical Microbiology 08/1999; 37(8):2479-82. · 4.23 Impact Factor
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    ABSTRACT: Pseudomonas aeruginosa was isolated from sinks of washing basins, showers, toilets and bathtubs, from the personnel and patients of a mixed infectious disease ward in a German children's hospital during a prospective 4-week epidemiological study. 81% of all sinks were contaminated with P. aeruginosa strains. Upon entering the hospital, all personnel hand cultures were P. aeruginosa-negative. However, during duty, 42.5% of the personnel members carried different P. aeruginosa strains on their hands. Detection of P. aeruginosa strains in sinks preceding the isolation of identical genotypes from personnel hands suggested a transmission route from sinks to hands. Opening of water taps generated aerosols containing P. aeruginosa sink organisms which contaminated hands during hand washing. Survival times of various P. aeruginosa strains in aerosols was dependent on strain characteristics, light and humidity, and t 1/2 differed between 3-76 min. Heating of washing basin sinks to 70 degrees C with a new, safe and inexpensive device inhibited bacterial growth in sinks, generation of P. aeruginosa aerosols, and resulted in hand cultures negative for P. aeruginosa after washing.
    Zentralblatt für Hygiene und Umweltmedizin = International journal of hygiene and environmental medicine 06/1991; 191(5-6):494-505.
  • K Botzenhart · C Wolz · G Döring
    Antibiotics and chemotherapy 02/1991; 44:8-12.

Publication Stats

2k Citations
120.27 Total Impact Points

Institutions

  • 1987–2007
    • University of Tuebingen
      • Faculty of Medicine
      Tübingen, Baden-Wuerttemberg, Germany
  • 2000
    • Harvard Medical School
      • Department of Medicine
      Boston, Massachusetts, United States