Biomedical subjects

John E Degener

Publications and source records attributed to John E Degener.

16 recordsLinked to original sources

PubMed2006

Is self-medication with antibiotics in Europe driven by prescribed use?

BACKGROUND: Self-medication with antibiotics may increase the risk of inappropriate use and the selection of resistant bacteria. One of the triggers for using self-medication may be past experience with antibiotics prescribed by health professionals. We examined the association between prescribed use and self-medication with antibiotics. METHODS: A population survey was conducted in 19 European countries, covering 15,548 respondents. Multinomial logistic regression analysis was used to study the relationship between prescribed use and self-medication for all symptoms/diseases and for upper respiratory tract infections (URTIs). RESULTS: The association between prescribed use and self-medication was modified by source of self-medication, region in Europe and education. This association was consistently stronger for self-medication from leftovers than from other sources, primarily directly from a pharmacy. It was stronger also for respondents from Northern/Western Europe than respondents from Eastern Europe and Southern Europe and those with low education. Prescribed use for URTIs (minor ailments such as throat symptom, influenza, etc.) increased the likelihood of self-medication with leftover antibiotics for these symptoms/diseases in all European regions. CONCLUSIONS: Our study shows consistent associations between prescribed use and self-medication with antibiotics from leftovers, but has not been able to support the hypothesis that self-medication from other sources than leftovers is triggered by earlier prescribed use. Preventing leftovers may be one effective way of preventing self-medication. This can be achieved by ensuring that the amount dispensed corresponds to the amount prescribed, by educating patients and by making doctors aware that prescribing for minor ailments may increase the risk of self-medication for such ailments.

Anti-Bacterial Agents↗

PubMed2006

Outbreak of Serratia marcescens colonization and infection traced to a healthcare worker with long-term carriage on the hands.

OBJECTIVE: To reveal the source of a nosocomial outbreak of colonization and infection with a strain of Serratia marcescens positive for Guiana extended-spectrum beta-lactamase 1 (GES-1) that occurred among patients in a neurosurgical intensive care unit (ICU) in a Dutch university medical center from May 2002 through March 2003. METHODS: Samples from the environment and from the hands of healthcare workers (HCWs) were cultured. A retrospective case-control study was carried out. RESULTS: Fifteen neurosurgical ICU patients who had 1 or more cultures that yielded the epidemic strain of S. marcescens from May 2002 through March 2003 were defined as case patients and matched with 30 control patients. Environmental cultures did not reveal a prominent source of S. marcescens. Cultures of specimens from the hands of 100 HCWs revealed colonization of a single HCW with the epidemic strain. Although this HCW instantly went on leave, serial cultures detected prolonged carriage of the epidemic strain on the hands of the HCW for 3 months. The skin of the HCW's hands was psoriatic. The epidemic abruptly ended after the colonized HCW went on leave. Retrospective case-control analysis showed that the patients colonized or infected with S. marcescens received significantly more nursing care from the colonized HCW than did control patients (P<.05). From February 2004 through October 2004, a second cluster of 3 patients was detected with the epidemic strain of S. marcescens. In October 2004, the formerly colonized HCW appeared to have carriage of the epidemic strain on the hands again. CONCLUSIONS: A single HCW with the epidemic strain of S. marcescens on the hands was considered the source of this outbreak.

Academic Medical Centers↗

PubMed2006

Limited effect of patient and disease characteristics on compliance with hospital antimicrobial guidelines.

OBJECTIVE: Physicians frequently deviate from guidelines that promote prudent use of antimicrobials. We explored to what extent patient and disease characteristics were associated with compliance with guideline recommendations for three common infections. METHODS: In a 1-year prospective observational study, 1,125 antimicrobial prescriptions were analysed for compliance with university hospital guidelines. RESULTS: Compliance varied significantly between and within the groups of infections studied. Compliance was much higher for lower respiratory tract infections (LRTIs; 79%) than for sepsis (53%) and urinary tract infections (UTIs; 40%). Only predisposing illnesses and active malignancies were associated with more compliant prescribing, whereas alcohol/ intravenous drug abuse and serum creatinine levels >130 micromol/l were associated with less compliant prescribing. Availability of culture results had no impact on compliance with guidelines for sepsis but was associated with more compliance in UTIs and less in LRTIs. Narrowing initial broad-spectrum antimicrobial therapy to cultured pathogens was seldom practised. Most noncompliant prescribing concerned a too broad spectrum of activity when compared with guideline-recommended therapy. CONCLUSION: Patient characteristics had only a limited impact on compliant prescribing for a variety of reasons. Physicians seemed to practise defensive prescribing behaviour, favouring treatment success in current patients over loss of effectiveness due to resistance in future patients.

Anti-Infective Agents↗

PubMed2006

Denaturing gradient gel electrophoresis as a diagnostic tool in periodontal microbiology.

Bacteria play an important role in the initiation and progression of periodontal diseases and are part of a biofilm, which can contain over 100 different species. The aim of the present study was to show the potential of denaturing gradient gel electrophoresis (DGGE) as a tool for the detection of clinically relevant species and to compare the results of detection by DGGE with those by PCR and culturing. Hybridization of the bands from the DGGE profiles with species-specific probes was developed to confirm the band positions in the marker obtained with reference strains. The sensitivities of DGGE compared to those of cultivation for the detection of Actinobacillus actinomycetemcomitans, Porphyromonas gingivalis, Prevotella intermedia, and Tannerella forsythensis were 100, 100, 88, and 100%, respectively; and the sensitivities of DGGE compared to those of PCR were 100, 90, 88, and 96%, respectively. DGGE as a diagnostic tool could easily be extended to other species, as shown for Treponema denticola, which could be detected in 48% of the samples. Three different groups of A. actinomycetemcomitans serotypes could be distinguished by DGGE (i.e., a group comprising serotypes a, d, e, and f; a group comprising serotype b; and a group comprising serotype c). Amplicons from P. gingivalis and T. denticola migrated to the same position in the gel, and P. intermedia produced multiple bands. In the present study we show that the DGGE profiles represent clinically relevant species which can be detected by hybridization with species-specific probes. With DGGE, large numbers of samples can be analyzed for different species simultaneously, and DGGE may be a good alternative in periodontal microbial diagnostics.

Bacteria↗

PubMed2005

Improving compliance with hospital antibiotic guidelines: a time-series intervention analysis.

OBJECTIVES: This study investigated the impact of a combined intervention strategy to improve antimicrobial prescribing at University Hospital Groningen. For the intervention, the antimicrobial treatment guidelines were updated and disseminated in paperback and electronic format. The credibility of the guidelines was improved by consultation with users. In a second phase, academic detailing (AD) was used to improve specific areas of low compliance with the guidelines. MATERIALS AND METHODS: Prescribing data were prospectively collected for 2869 patients receiving 7471 prescriptions for an antimicrobial for an infection covered by the guidelines between July 2001 and September 2003. After collection of baseline data, the guidelines were actively disseminated in February 2002. Next, after a 5 month interval, a second intervention, i.e. an AD approach, addressed suboptimal prescribing of ciprofloxacin and co-amoxiclav. Segmented regression analysis was used to analyse the interrupted time-series data. RESULTS: At baseline, compliance with the drug choice guidelines was 67%. The first intervention showed a significant change in the level of compliance of +15.5% (95% CI: 8%; 23%). AD did not lead to statistically significant additional changes in already high levels +12.5% (95% CI:-3%; 28%) of compliance. Post-intervention compliance was stable at 86%. CONCLUSIONS: Updating the guidelines in close collaboration with the specialists involved followed by active dissemination proved to be an efficient way to improve compliance with guideline recommendations. An 86% compliance level was achieved in this study without compulsory measures. A ceiling effect may have limited the added value of AD.

Amoxicillin-Potassium Clavulanate Combination↗

PubMed2005

Fluorescent in situ hybridization with specific DNA probes offers adequate detection of Enterococcus faecalis and Enterococcus faecium in clinical samples.

Enterococcus faecalis and Enterococcus faecium are among the leading causes of hospital-acquired infections. Reliable and quick identification of E. faecalis and E. faecium is important for accurate treatment and understanding their role in the pathogenesis of infections. Fluorescent in situ hybridization (FISH) of whole bacterial cells with oligonucleotides targeted at the 16S rRNA molecule leads to a reduced time to identification. In clinical practice, FISH therefore can be used in situations in which quick identification is necessary for optimal treatment of the patient. Furthermore, the abundance, spatial distribution and bacterial cell morphology can be observed in situ. This report describes the design of two fluorescent-labelled oligonucleotides that, respectively, detect the 16S rRNA of E. faecalis and the 16S rRNA of E. faecium, Enterococcus hirae, Enterococcus mundtii, Enterococcus villorum and Enterococcus saccharolyticus. Different protocols for the application of these oligonucleotides with FISH in different clinical samples such as faeces or blood cultures are given. Enterococci in a biofilm attached to a biomaterial were also visualized. Embedding of the biomaterial preserved the morphology and therefore the architecture of the biofilm could be observed. The usefulness of other studies describing FISH for detection of enterococci is generally hampered by the fact that they have only focused on one material and one protocol to detect the enterococci. However, the results of this study show that the probes can be used both in the routine laboratory to detect and determine the enterococcal species in different clinical samples and in a research setting to enumerate and detect the enterococci in their physical environment.

Biocompatible Materials↗

PubMed2005

Atomic force microscopy study on specificity and non-specificity of interaction forces between Enterococcus faecalis cells with and without aggregation substance.

Enterococcus faecalis is one of the leading causes of hospital-acquired infections, and indwelling medical devices are especially prone to infection. E. faecalis expressing aggregation substance (Agg) adheres to biomaterial surfaces by means of positive cooperativity, i.e. the ability of one adhering organism to stimulate adhesion of other organisms in its immediate vicinity. In this study, atomic force microscopy (AFM) was used to measure the specificity and non-specificity of interaction forces between E. faecalis cells with and without Agg. Bacteria were attached to a substratum surface and a tip-less cantilever. Two E. faecalis strains expressing different forms of Agg showed nearly twofold higher interaction forces between bacterial cells than a strain lacking Agg [adhesive force (F(adh)), -1.3 nN]. The strong interaction forces between the strains with Agg were reduced after adsorption of antibodies against Agg from -2.6 and -2.3 nN to -1.2 and -1.3 nN, respectively. This suggests that the non-specific interaction force between the enterococci amounts to approximately 1.2 nN, while the specific force component is only twofold stronger. Comparison of the results of the AFM interaction forces with the positive cooperativity after adhesion to a biomaterial in a parallel-plate flow chamber showed that in the absence of strong interaction forces between the cells, positive cooperativity was also absent. In conclusion, this is believed to be the first time that the influence of specific antibodies on interaction forces between E. faecalis cells has been demonstrated by AFM, thereby experimentally distinguishing between specific and non-specific force components.

Adhesins, Bacterial↗

PubMed2004

Adherence barriers to antimicrobial treatment guidelines in teaching hospital, the Netherlands.

To optimize appropriate antimicrobial use in a university hospital and identify barriers hampering implementation strategies, physicians were interviewed regarding their opinions on antimicrobial policies. Results indicated that effective strategies should include regular updates of guidelines that incorporate the views of relevant departments and focus on addressing senior staff and residents because residents do not make independent decisions in a teaching-hospital setting.

Anti-Bacterial Agents↗

PubMed2004

Methicillin-resistant Staphylococcus aureus in Europe, 1999-2002.

We explored the variation in proportions of methicillin-resistant Staphylococcus aureus (MRSA) between and within countries participating in the European Antimicrobial Resistance Surveillance System and temporal trends in its occurrence. This system collects routine antimicrobial susceptibility tests for S. aureus. We examined data collected from January 1999 through December 2002 (50,759 isolates from 495 hospitals in 26 countries). MRSA prevalence varied almost 100-fold, from <1% in northern Europe to >40% in southern and western Europe. MRSA proportions significantly increased in Belgium, Germany, Ireland, the Netherlands, and the United Kingdom, and decreased in Slovenia. Within countries, MRSA proportions varied between hospitals with highest variance in countries with a prevalence of 5% to 20%. The observed trends should stimulate initiatives to control MRSA at national, regional, and hospital levels. The large differences between hospitals indicate that efforts may be most effective at regional and hospital levels.

Europe↗

PubMed2002

Genogrouping and incidence of virulence factors of Enterococcus faecalis in liver transplant patients differ from blood culture and fecal isolates.

Enterococcus faecalis is a leading cause of infections in liver transplant patients. This study reviewed the incidence of virulence factors such as hemolysin, gelatinase, aggregation substances (asa1 and asa373), or the enterococcal surface protein (Esp) in isolates from liver transplant patients. In total, 133 isolates from liver transplant patients were compared with 47 isolates from feces of healthy volunteers and 66 isolates from blood cultures. Amplified fragment length polymorphism (AFLP) analysis indicates that the isolates from different clinical subgroups can be divided into genogroups with an AFLP similarity of >80% and different virulence factors. Hemolysin and asa1 might be associated with infection, as they are more frequent in isolates from blood cultures and transplant patients. Esp might be associated with colonization and spread, because it is more frequent in isolates from feces of healthy volunteers and transplant patients. An epidemic esp gene-positive strain among liver transplant patients supports this hypothesis.

Bacteremia↗

PubMed2002

High level expression and secretion of truncated forms of herpes simplex virus type 1 and type 2 glycoprotein D by the methylotrophic yeast Pichia pastoris.

Herpes simplex virus type 1 and 2 (HSV-1 and -2) glycoproteins D (gD-1 and gD-2) play a role in the entry of the virus into the host cell. Availability of substantial amounts of these proteins, or large fragments thereof, will be needed to allow studies at the molecular level. We studied the potency of the Pichia pastoris yeast expression system to produce soluble forms of gD. The DNA sequences encoding the extracellular domains of gD [amino acids 1-314 (gD-1(1-314)) and amino acids 1-254 (gD-1(1-254)) of gD-1 and amino acids 1-314 of gD-2 (gD-2(1-314))] were cloned into the P. pastoris yeast expression vector pPIC9. Two truncated forms of gD-1 were fitted with a His tail (designated as gD-1(1-314His) and gD-1(1-254His)) to facilitate their purification. Large amounts of gD-1(1-314) and gD-1(1-314His) (280-300mg/L induction medium) were produced. The yields of recombinant gD-1(1-254) and gD-1(1-254His) were lower: 20-36mg/L, and the yield of the gD-2(1-314) fragment was much lower: 6mg/L. SDS-PAGE analysis revealed multiple glycosylated species of the larger gD fragments, ranging in apparent molecular weight from 31 to 78kDa. The smaller gD-1(1-254) fragment appeared as two bands with molecular weights of 33 and 31kDa. All recombinant proteins produced by P. pastoris were recognized, as expected, by a panel of MAbs (A16, DL6, A18, DL11, HD1, ABDI, and AP7). In addition, we showed that gD-1(1-314), gD-2(1-314), and gD-1(1-254His) were able to interfere with binding of HSV to susceptible cells. These results indicate that the conformations of the recombinant proteins closely resemble those of native gD.

Chromatography, High Pressure Liquid↗

PubMed2002

Enterococcus faecalis surface proteins determine its adhesion mechanism to bile drain materials.

An important step in infections associated with biliary drains is adhesion of micro-organisms to the surface. In this study the role of three surface proteins of Enterococcus faecalis (enterococcal surface protein, aggregation substances 1 and 373) in the adhesion to silicone rubber, fluoro-ethylene-propylene and polyethylene was examined. Four isogenic E. faecalis strains with and without aggregation substances and one strain expressing enterococcal surface protein were used. The kinetics of enterococcal adhesion to the materials was measured in situ in a parallel plate flow chamber. Initial deposition rates were similar for all strains, whereas the presence of surface proteins increased the total number of adhering bacteria. Nearest neighbour analysis demonstrated that enterococci expressing the whole sex-pheromone plasmid encoding aggregation substances 1 or 373 adhered in higher numbers through mechanisms of positive cooperativity, which means that adhesion of bacteria enhances the probability of adhesion of other bacteria near these bacteria. Enterococci with the enterococcal surface protein did not adhere through this mechanism. These findings indicate that the surface proteins of E. faecalis play a key role in the adhesion to bile drains and bile drain associated infections.

Bacterial Adhesion↗

PubMed2002

Extensive set of 16S rRNA-based probes for detection of bacteria in human feces.

For the detection of six groups of anaerobic bacteria in human feces, we designed seven new 16S rRNA-based oligonucleotide probes. This set of probes extends the current set of probes and gives more data on the composition of the human gut flora. Probes were designed for Phascolarctobacterium and relatives (Phasco741), Veillonella (Veil223), Eubacterium hallii and relatives (Ehal1469), Lachnospira and relatives (Lach571), and Eubacterium cylindroides and relatives (Ecyl387), and two probes were designed for Ruminococcus and relatives (Rbro730 and Rfla729). The hybridization conditions for the new probes were optimized for fluorescent in situ hybridization, and the probes were validated against a set of reference organisms. The probes were applied to fecal samples of 11 volunteers to enumerate their target bacterial groups. The Phasco741 and Veil223 probes both detected average numbers below 1% of the total number of bacteria as determined with the bacterial kingdom-specific Bact338 probe. The Ecyl387 probe detected about 1.4%, the Lach571 and Ehal1469 probes detected 3.8 and 3.6%, respectively, and a combination of the Rbro730 and Rfla729 probes detected 10.3%. A set of 15 probes consisting of probes previously described and those presented here were evaluated in hybridization with the fecal samples of the same volunteers. Together, the group-specific probes detected 90% of the total bacterial cells.

Bacteria↗

PubMed2002

Adhesion to bile drain materials and physicochemical surface properties of Enterococcus faecalis strains grown in the presence of bile.

The aim of this study is to determine whether growth in the presence of bile influences the surface properties and adhesion to hydrophobic bile drain materials of Enterococcus faecalis strains expressing aggregation substance (Agg) or enterococcal surface protein (Esp), two surface proteins that are associated with infections. After growth in the presence of bile, the strains were generally more hydrophobic by water contact angles and the zeta potentials were more negative than when the strains were grown in the absence of bile. Nitrogen was found in lower surface concentrations upon growth in the presence of bile, whereas higher surface concentrations of oxygen were measured by X-ray photoelectron spectroscopy. Moreover, an up to twofold-higher number of bacteria adhered after growth in bile for E. faecalis not expressing Agg or Esp and E. faecalis with Esp on its surface. E. faecalis expressing Agg did not adhere in higher numbers after growth in bile, possibly because they mainly adhere through positive cooperativity and less through direct interactions with a substratum surface. Since adhesion of bacteria is the first step in biomaterial-centered infection, it can be concluded that growth in bile increases the virulence of E. faecalis.

Adhesins, Bacterial↗

PubMed2002

A European study on the relationship between antimicrobial use and antimicrobial resistance.

In Europe, antimicrobial resistance has been monitored since 1998 by the European Antimicrobial Resistance Surveillance System (EARSS). We examined the relationship between penicillin nonsusceptibility of invasive isolates of Streptococcus pneumoniae and antibiotic sales. Information was collected on 1998-99 resistance data for invasive isolates of S. pneumoniae to penicillin, based on surveillance data from EARSS and on outpatient sales during 1997 for beta-lactam antibiotics and macrolides. Our results show that in Europe antimicrobial resistance of S. pneumoniae to penicillin is correlated with use of beta-lactam antibiotics and macrolides.

Anti-Bacterial Agents↗

PubMed2001

The lactococcal secondary multidrug transporter LmrP confers resistance to lincosamides, macrolides, streptogramins and tetracyclines.

The active efflux of toxic compounds by (multi)drug transporters is one of the mechanisms that bacteria have developed to resist cytotoxic drugs. The authors describe the role of the lactococcal secondary multidrug transporter LmrP in the resistance to a broad range of clinically important antibiotics. Cells expressing LmrP display an increased resistance to the lincosamide, streptogramin, tetracycline and 14- and 15-membered macrolide antibiotics. The streptogramin antibiotic quinupristin, present in the fourth-generation antibiotic RP 59500, can inhibit LmrP-mediated Hoechst 33342 transport, but is not transported by LmrP, indicating that quinupristin acts as a modulator of LmrP activity. LmrP-expressing Lactococcus lactis cells in which a proton-motive force is generated accumulate significantly less tetracycline than control cells without LmrP expression. In contrast, LmrP-expressing and control cells accumulate equal amounts of tetracycline in the absence of metabolic energy. These findings demonstrate that the increased antibiotic resistance in LmrP-expressing cells is a result of the active extrusion of antibiotics from the cell.

Anti-Bacterial Agents↗