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Biomedical subjects

J E Degener

Publications and source records attributed to J E Degener.

At least 19 recordsLinked to original sources

[Optimizing the antibiotics policy in The Netherlands. VIII. Revised SWAB guidelines for antimicrobial therapy in adults with community-acquired pneumonia].

The Dutch Working Party on Antibiotic Policy (SWAB) has revised the 1998 guideline for community-acquired pneumonia (CAP) in light of changing resistance patterns for common pathogens and new developments in epidemiology, diagnostic testing and treatment strategies. The current guideline is applicable to both primary and inpatient care, and has been developed by delegates of all professional organisations involved in the treatment of CAP, following recommendations for evidence-based guideline development. Assessment of a patient's 'severity of illness' at presentation is considered important when choosing an optimal empirical antibiotic regimen for CAP. Severely-ill patients should be treated with antibiotics covering the most important expected pathogens, including Legionella. Assessment of the severity of illness may be facilitated by the use of validated scoring systems like the pneumonia severity index and the 'confusion, urea, respiratory-rate, blood-pressure, 65-years-of-age' (CURB-65) score. Patients can also be stratified based on their location during treatment: in the community, a normal ward or an intensive-care unit. Legionella urine antigen testing is considered an important tool in the process of deciding on an optimal antibiotic regimen for CAP. Empirical therapy should be replaced with pathogen-directed therapy if the causative agent is identified.

Age Factors↗

Reliability of assessment of adherence to an antimicrobial treatment guideline.

Assessment procedures for adherence to a guideline must be reliable and credible. The aim of this study was to explore the reliability of assessment of adherence, taking account of the professional backgrounds of the observers. A secondary analysis explored the impact of case characteristics on assessment. Six observers (two hospital pharmacists, two internists and two clinical microbiologists) assessed a random sample of 22 prescriptions made to infectious disease cases admitted to a department of internal medicine between February and August 2001. Agreement between observers with regard to adherence of these prescriptions to guideline recommendations concerning drug choice, duration of treatment, dosage and route of administration was measured using Cohen's kappa. Case characteristics were compared between cases where observers agreed and disagreed with two-sided Fisher's exact test. Agreement between all professionals was moderate for drug choice (0.59), fair for duration of therapy (0.36), moderate for dosage (0.48), and fair for route of administration (0.37). Agreement on drug choice was good within (0.75 and 0.83) and between (0.74) the internists and the hospital pharmacists, but was less within (0.31) the clinical microbiologists and between the clinical microbiologists and the internists (0.44) and the hospital pharmacists (0.42). Within the clinical microbiologists, agreement was good for dosage (0.79) and route of administration (0.66). There was frequent disagreement between observers regarding cases with combination therapy and non-immunocompromised patients. Despite the small number of cases, our results suggest that internists and hospital pharmacists can reliably be used to assess adherence for drug choice. The level of agreement seems to be affected by combination therapy and the immune status of the patient.

Aged↗

Molecular epidemiology of Enterococcus faecalis in liver transplant patients at University Hospital Groningen.

We report the molecular epidemiology of Enterococcus faecalis in liver transplant patients transplanted at the University Hospital Groningen (The Netherlands) as determined by amplified fragment length polymorphism (AFLP) typing. A total of 133 E. faecalis isolates were cultured from the faeces and throat (95 isolates) or clinical sites (35 isolates) of 43 liver transplant patients. Among these 133 isolates, 15 different AFLP types could be identified with 90% AFLP similarity. Of these 15 groups, nine contained isolates from more than one patient, which may indicate transmission of E. faecalis isolates between patients. In five of these groups transmission could be explained by the fact that patients carrying identical strains were staying in the same ward at the same time. One of these epidemic isolates (AFLP type K) distinguished itself by colonizing 23 liver transplant patients during 15 months. Antimicrobial susceptibility testing did not reveal any multi-resistant isolates. This study showed that transmission of susceptible E. faecalis isolates occurs frequently on the liver transplant wards. Detection of this transmission and understanding of the mechanism is important, as it might also be an indicator of possible transmission of enterococci resistant to antibiotics.

Adult↗

Denaturing gradient gel electrophoresis analysis to study bacterial community structure in pockets of periodontitis patients.

Bacteria are involved in the onset and progression of periodontitis. A promising molecular technique, denaturing gradient gel electrophoresis (DGGE), to study microbial population dynamics in the subgingival pocket is presented. Twenty-three samples were taken from the subgingival pockets of nine patients and six healthy family members. From four periodontitis patients, 12 samples were evaluated before, 1 day after and 3 months after treatment. Part of the 16S rRNA gene of all bacteria was amplified by PCR and separated by DGGE, creating banding patterns representative of the community structure. Shifts in composition and diversity of the microbial population could be determined semiquantitatively, and this showed that treatment resulted in a decrease in the diversity of the population. After 3 months a microbial population 33-47% different from the population before treatment had re-established. Intense bands representing Exiguobacterium aurantiacum were present in 13 out of 25 samples, indicating that this species may play a role in periodontal disease.

Actinomyces↗

Implications of the simultaneous presence of metronidazole-susceptible and -resistant Helicobacter pylori colonies within a single biopsy specimen.

This study examined whether the simultaneous presence of metronidazole-susceptible and -resistant Helicobacter pylori colonies in a single biopsy specimen is caused by a multiple strain infection with a susceptible and a resistant strain or by two subpopulations within a single strain. Single colonies obtained from seven biopsy specimens known to harbour both susceptible and resistant Helicobacter pylori were fingerprinted by restricted fragment length polymorphism typing of the ureC gene and by the random amplified polymorphic DNA procedure. Metronidazole susceptibility was determined by the E test. The results indicated that the occurrence of metronidazole-resistant and metronidazole-susceptible bacteria within a single biopsy does not imply the presence of a multiple strain infection with one resistant and one sensitive strain.

Anti-Bacterial Agents↗

The importance of vacA, cagA, and iceA genotypes of Helicobacter pylori infection in peptic ulcer disease and gastroesophageal reflux disease.

OBJECTIVE: To study the relationship between the presence of H. pylori virulence factors and clinical outcome in H. pylori infected patients. METHODS: DNA was isolated from an antral biopsy sample and vacA, cagA, and iceA genotype were determined by PCR and a reverse hybridization technique in 183 patients with culture-proven H. pylori infection: 51 with peptic ulcer disease (PUD), 62 with gastroesophageal reflux disease (GERD), and 70 with a normal endoscopy (gastritis only; GO). RESULTS: Forty-four samples (24%) showed more than one allelic variant in the vacA s- or in-region and/or both iceA1 and iceA2 genotypes, indicating multiple strain infection. These were excluded from statistical analysis. vacA s1 and cagA were significantly more common in PUD than in GERD and GO. Logistic regression analysis showed that GERD patients were more often infected with strains lacking both cagA and iceA than GO patients (OR = 0.36; CI = 0.15-0.89). Trend analysis showed that GERD patients were most often infected with less virulent strains (p < 0.002). CONCLUSION: Multiple strain infection is common. H. pylori strains possessing the vacA s1 genotype and/or cagA are associated with PUD. GERD patients, infected with H. pylori, mostly carry less virulent strains possessing neither cagA nor iceA1. Our findings support the hypothesis that virulent strains protect against the development of GERD.

Antigens, Bacterial↗

Development of 16S rRNA-based probes for the Coriobacterium group and the Atopobium cluster and their application for enumeration of Coriobacteriaceae in human feces from volunteers of different age groups.

Two 16S rRNA-targeted probes were developed: one for the Coriobacterium group and the other for the Atopobium cluster (which comprises most of the Coriobacteriaceae species, including the Coriobacterium group). The new probes were based on sequences of three new Coriobacteriaceae strains isolated from human feces and clinical material and sequences from databases. Application of the probes to fecal samples showed that formula-fed infants had higher numbers of Coriobacterium group cells in their feces than breast-fed infants. In addition, based on the presented results, it is hypothesized that with the increasing age of a person, the diversity of Atopobium cluster species present in the feces increases.

Actinobacteria↗

Rapid identification of bacteria in blood cultures by using fluorescently labeled oligonucleotide probes.

The applicability of whole-cell hybridization for the identification of pathogenic bacteria in blood from septic patients was examined. Oligonucleotide probes, fluorescently labeled with fluorescein isothiocyanate, directed against the variable regions of the 16S rRNAs of the following bacterial species and/or genera were used: Streptococcus spp., Enterococcus faecalis, Staphylococcus aureus, coagulase-negative staphylococci (CoNS), Escherichia coli, Pseudomonas aeruginosa, and the Enterobacteriaceae family. A probe specific for the rRNAs of almost all bacteria and its complementary, reversed counterpart was used as positive and negative control, respectively. The probes were used in conjunction with a fast and simple-to-use protocol for whole-cell hybridization. This protocol yields an identification after 25 to 45 min, depending on whether the bacterium is gram positive or gram negative. A total of 182 blood samples which tested positive in a blood culture machine were investigated. All probes except for the ones for S. aureus and the CoNS showed sensitivities and specificities of 1.000. It was concluded that whole-cell hybridization is well suited for the fast screening of septic blood containing streptococci and/or enterococci or gram-negative rods.

Bacteremia↗

[European strategy for control of resistance to antibiotics].

The problem of international spread of bacterial resistance requires development of a strategy at worldwide or at least at European level. Clinically relevant monitoring systems for resistance and use of antibiotics have to be implemented to support the guidelines on prescription of antibiotics. Every hospital should establish an 'antibiotics team' controlling the prescription of antimicrobials and the observance of local formulary agreements. Veterinary use of growth promoting antimicrobials related to substances used in human medicine should be terminated. Future research should be aimed at resolving the problem of resistance to antimicrobials.

Animals↗

[Health council report: "Antimicrobial growth promoters"].

The Health Council of the Netherlands has issued a report on the risk of development of resistance among bacteria as result of the use of antibiotics as growth promotors in livestock farming. The committee appointed by the Health Council conclude that the use of antimicrobial growth promotors contributes to the problem of resistance among human pathogens. The conclusions are based on evidence regarding the development of resistance in livestock as the result of the use of antimicrobial growth promotors, the possibility of colonisation/infection of humans with resistant bacteria from the intestinal flora of productive livestock, and the transfer of resistance genes from livestock bacteria to human pathogenic microorganisms. Effective measures for the limitation of the public health risk should focus on termination of the use of antimicrobial growth promotors that confer resistance to (related) antibiotics currently used (or which will be available) to treat patients suffering from bacterial infections. In addition, the committee advised ending the use of antimicrobial growth promotors in 3 years.

Animals↗

Rapid emergence of resistant coagulase-negative staphylococci on the skin after antibiotic prophylaxis.

One approach for prosthetic vascular surgery is to continue antimicrobial prophylaxis while intravascular lines and catheters are in place. However this may give rise to antimicrobial resistance in the colonizing bacterial flora. We studied 37 patients undergoing vascular surgery, who received either co-amoxyclav for three days (group 1), ofloxacin plus metronidazole for three days (group 2) or for one day (group 3), respectively. Seventeen hospitalized patients not undergoing surgery or receiving antibiotics were studied as controls. In groups I and II there was a significant decline in susceptibility to cloxacillin (12.8% respectively 23.6%) and ofloxacin (0.5% and 85% respectively) in skin staphylococci. The results from group 3 were intermediate. Molecular typing showed that the patient's susceptible community-derived strains were replaced by genetically unrelated resistant strains, probably hospital derived. Long-term prophylaxis should be avoided as colonization occurs with resistant strains.

Amoxicillin-Potassium Clavulanate Combination↗

Evaluation of the effects of storage in two different swab fabrics and under three different transport conditions on recovery of aerobic and anaerobic bacteria.

Recovery of six anaerobic and five aerobic pathogens from viscose swabs and polyurethane swabs (Culturette EZ) was evaluated quantitatively, and transport in aerobic dry tubes, aerobic Amies transport medium (Transwab), and anaerobic universal transport medium (Port-a-Cul) was compared. The Culturette EZ in aerobic dry tubes gave the highest recovery levels. Data obtained with clinical specimens confirmed these results.

Bacteria, Aerobic↗

[Urinary antigen test as a screen for the diagnosis of beta-hemolytic streptococcal infections in newborn infants].

OBJECTIVE: To differentiate between neonates with high and low risk of infections caused by group B beta-haemolytic streptococci (GBS), by using the urinary group B streptococcal antigen test. DESIGN: Retrospective. SETTING: Medical Centre Leeuwarden and Public Health Laboratory, Friesland, the Netherlands. METHODS: In a period of two years clinical, haematological and microbiological (including urinary group B streptococcal antigen detection) data were collected in newborns and their mothers who met one or more of the following criteria: a previous affected child, prolonged (> or = 12 hrs) rupture of membranes, fever in labour, unexpected preterm delivery, unexplained perinatal asphyxia. On the basis of surveillance cultures a colonization rate was made. GBS infection was 'suspected' in an unwell infant with a 'high' colonization rate; infection with GBS was 'proved' by a positive blood culture with GBS. RESULTS: 6 of 342 neonates had an infection with GBS. Risk of invasive infection increased with higher colonization rates. Sensitivity of the antigen test to detect colonization was low, sensitivity to detect neonatal infection was high (51 versus 100%). The negative predictive value of urinary antigen testing was 100%. Prolonged rupture of membranes (1.5% risk of infection) and maternal fever (5%) were the most important risk factors. CONCLUSION: In healthy neonates with risk factors but with a negative antigen detection test the risk of GBS infection is extremely low. In children with a risk factor a positive test result can indicate heavy colonization or infection. These children should be carefully observed and examined.

Adult↗

16S ribosomal RNA-targeted oligonucleotide probes for monitoring of intestinal tract bacteria.

BACKGROUND: The composition of a sample of faecal bacteria can be determined by culturing different dilutions on specific media. However, not all bacteria can be cultured and media are not always specific. With a culture-independent approach a more accurate picture of the composition of the intestinal flora may be obtained. METHODS: Fluorescently labelled oligonucleotide probes targeted at 16S ribosomal RNA sequences specific for a bacterial genus were designed and applied for fluorescence in situ hybridization (FISH) of bacteria in human faecal samples. RESULTS: The mean number of Bifidobacterium spp. and the total number of anaerobic bacteria per gram of faeces were determined by culturing and with the probe technique. Although in both cases the number of Bifidobacterium spp. was about the same, 2.38 x 10(9) and 2.45 x 10(9), it was found that the contribution of Bifidobacterium spp. to the total composition is overestimated due to the lower number of total anaerobic bacteria estimated by culturing. CONCLUSION: Genus-specific or group-specific fluorescent 16S rRNA probes may become an invaluable tool in gut ecology studies.

Bacteria, Anaerobic↗

The relationship between the use of flucloxacillin, vancomycin, aminoglycosides and ciprofloxacin and the susceptibility patterns of coagulase-negative staphylococci recovered from blood cultures.

Antibiotic use is a cause of selection of multiresistant bacterial strains. Over three years (1990-1992) we studied the relation between the use of flucloxacillin, vancomycin, aminoglycosides and ciprofloxacin and the susceptibility of coagulase-negative staphylococci (CNS) recovered from blood cultures. Although there was no increase in the use of flucloxacillin, the susceptibility of CNS to this antibiotic decreased from 25% to 6%. No increase in aminoglycoside use was seen, though the use in the non-surgical intensive care unit was 40 times the average use in the hospital. The susceptibility to gentamicin declined from 36% to 15% for the rest of the hospital and to zero for the non-surgical intensive care unit. Vancomycin use did not change in the hospital as a whole, but the use in the haematological unit was about ten times that in the rest of the hospital. No single resistant strain (vancomycin MIC > or = 4 mg/L) was found. A three-fold increase in ciprofloxacin use was seen. After a decline in the susceptibility to ciprofloxacin from 72% to 58% in 1991, there was a small recovery to 62% in 1992. The use in the haematological unit was about 20 times that in the rest of the hospital. Ciprofloxacin susceptibility declined from 40% to 25% in that unit in 1991. In 1992 there was a small recovery to 29%.

Aminoglycosides↗