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Biomedical subjects

H Westh

Publications and source records attributed to H Westh.

At least 37 records · Page 2Linked to original sources
PubMed1996

Hepatitis B core antibody screening in a high prevalence group: comparison of three enzyme immunoassays using receiver operating characteristic analysis.

Selected sera from 296 homosexual men were screened by 3 commercially available anti-HBc enzyme immunoassays (EIA). All patients could be classified either as non-immune to hepatitis B, or with current or previous hepatitis B infection. Using the cut-off optical density values (O.D. values) recommended by the respective manufacturers, the results from these three assays were identical for 83% of the serum samples. For anti-HBc reactivity, the ratio (percentage) was calculated using O.D. sample x 100 divided by the O.D. cut-off value. Employing these ratios, sensitivities and specificities for the three assays were compared. All assays performed well when analyzed by receiver operating characteristic curves with area under the curves of 96-97%. A higher specificity, with only a marginal loss of sensitivity could be achieved by lowering the cut-off to 55% for the Enzygost EIA, to 85% for the Enzygost-monoclonal EIA and to 60% for the Corzyme EIA. Using the modified cut-off values, the results with the three assays agreed for 93% of the serum samples.

Hepatitis Antibodies↗
PubMed1996

Vancomycin-resistant enterococci at a large university hospital in Denmark.

Enterococci are part of the normal human fecal flora and also part of the fecal flora of many animals. Vancomycin- and ampicillin-resistant enterococci give rise to infections that may virtually be untreatable with antibiotics. Antibiotic use in humans is a risk factor for development or selection of vancomycin-resistant enterococci. In animals the related glycopeptide avoparcin is used, especially in poultry, as a food additive to promote growth. Selective pressures for vancomycin-resistant enterococci are high in Denmark with the production of 105 million poultry and the use of 24,000 kg avoparcin per year. The possible impact on vancomycin resistance among human isolates of enterococci remains to be defined. Furthermore, there has been a 3-fold increase in vancomycin usage during the last 5 years at our hospital, from 2.4 to 7 kg/year. We examined 91 stool specimens from 67 patients in risk units at our hospital. Using a selective medium (KAA agar), 17 strains of Enterococcus faecium grew on the selective medium and 3 (18%) were vancomycin-resistant (MIC > 256 mg/l). Using PCR and an internal probe, vanA was found in the vancomycin-resistant enterococci. No association between vancomycin therapy and carriage of VRE was demonstrated in these patients.

Cross Infection↗
PubMed1996

Bacterial colonization and healing of venous leg ulcers.

UNLABELLED: The aim of the study was to evaluate a possible influence of selected bacterial species on healing of venous leg ulcers. Fifty-nine patients with venous leg ulcers were followed via frequent semiquantitative culture of bacteria from the ulcer surface and determination of the ulcer area over a period of 180 days. Occurrences of cellulitis were treated with systemic antibiotics. There was a significant difference in relative areas on days 90 and 180 when ulcers with growth of Pseudomonas aeruginosa were compared to those without (p = 0.0080 and 0.0133, respectively). Ulcers with P. aeruginosa were characterized to a great extent by enlargement in contrast to those without. Ulcers with growth of Staphylococcus aureus or haemolytic streptococci healed significantly more slowly than those without when relative areas were compared on day 180 (p = 0.0079 and 0.0492, respectively). Complete healing within the observation period of 180 days was observed in 10.5% of patients with P. aeruginosa and 35% of those without (p = 0.0631), in 21.6% of patients with S. aureus and 62.5% of those without (p = 0.0278), and in 10.5% of patients with haemolytic streptococci and 35% of those without (p = 0.0631). The initial areas of ulcers colonized with P. aeruginosa or S. aureus were significantly larger than those without, but no significant correlation between initial areas and ulcer healing was revealed. CONCLUSION: Our results suggest that P. aeruginosa in venous leg ulcers can induce ulcer enlargement and/or cause a healing delay. The results also suggest a healing delay caused by S. aureus and haemolytic streptococci. However, conclusions have to be treated with caution since P. aeruginosa was found in combination with haemolytic streptococci in 15.3% of the patients.

Bacterial Infections↗
PubMed1996

Glycopeptide susceptibility among Danish Enterococcus faecium and Enterococcus faecalis isolates of animal and human origin and PCR identification of genes within the VanA cluster.

The MICs of vancomycin and avoparcin were determined for isolates of Enterococcus faecium and isolates of Enterococcus faecalis recovered from the feces of humans and animals in Denmark. Two hundred twenty-one of 376 (59%) isolates of E. faecium and 2 of 133 (1.5%) isolates of E. faecalis were resistant to vancomycin (MICs, 128 to > or = 256 micrograms/ml), and all vancomycin-resistant isolates were resistant to avoparcin (MICs, 64 to > or = 256 micrograms/ml). All vancomycin-resistant isolates examined carried the vanA, vanX, and vanR genes, suggesting that a gene cluster similar to that of the transposon Tn1546 was responsible for the resistance.

Animals↗
PubMed1995

Prevalence of erm gene classes in erythromycin-resistant Staphylococcus aureus strains isolated between 1959 and 1988.

The epidemiology of the two common erythromycin resistance methylase (erm) genes ermA and ermC was analyzed by Southern blotting in 428 erythromycin-resistant Staphylococcus aureus strains isolated from blood between 1959 and 1988 in Denmark. ermA and/or ermC was present in 98% of the erythromycin-resistant strains tested. ermA was found only as a chromosomal insert and was solely responsible for erythromycin resistance in these strains until about 1971. ermA was the only erm gene found in 337 strains and was a single insert in 61% of these strains, two inserts were seen in 37%, and three inserts were found in 2%. Thirteen different ermA EcoRI restriction fragment length polymorphisms were identified. ermA was not found in strains of phage type patterns group II and type 95, which are very common today. ermC was found on a plasmid in 77 strains. ermC was first seen in 1971 and spread rapidly in the S. aureus population, with a 5- to 10-fold increase every 5 years, and in 1984 to 1988, it was responsible for erythromycin resistance in 72% of the strains. The predominant plasmid carrying ermC was 2.5 kb, while four plasmids were smaller and three were larger. ermC has been found in all phage type patterns. Eight strains contained combinations of ermA and ermC, and no erm gene was detected in six strains.

Base Sequence↗
PubMed1995

erm genes in erythromycin-resistant Staphylococcus aureus and coagulase-negative staphylococci.

Erythromycin-resistant S. aureus from general practice and a dermatology ward with a very high consumption of erythromycin was studied for ermA and ermC content by Southern blot analysis. The prevalence of these erm genes was also studied in coagulase-negative staphylococci from the same dermatology ward and in a collection of 15 S. aureus and 18 coagulase-negative staphylococci found in the same specimen from 15 different patients. ermA was only found as a chromosomal insert and ermC only on small plasmids. In erythromycin-resistant S. aureus from general practice ermC was responsible for 84% of erythromycin resistance, while 16% of the strains contained ermA. In 17 of 18 S. aureus strains from the dermatology ward a 2.5 kb plasmid contained ermC. Among 58 erythromycin-resistant coagulase-negative staphylococci only 2 (3%) had ermA, whereas 44 strains (76%) had ermC. ermA or ermC genes were common in S. epidermidis (36/38). However, in 20 isolates of erythromycin-resistant coagulase-negative staphylococci of other species, 10 had neither ermA nor ermC. ermC was the most common erm gene in both coagulase-negative staphylococci and S. aureus. In 11 of 15 patients with erythromycin-resistant S. aureus the co-isolated erythromycin-resistant coagulase-negative staphylococcus had another resistance mechanism, either another gene or a different phenotypic expression of the same gene. Resistance to pristinamycin, a streptogramin antibiotic only used in animals, was not found in S. aureus but was found in 14% of erythromycin-resistant coagulase-negative staphylococci.

Animals↗
PubMed1994

[Staphylococcus aureus--33-year epidemiology in Denmark. From hospital epidemics to endogenous infections?].

Data on 591,292 Staphylococcus aureus strains from Danish patients in the period 1960-1992 have shown that penicillin- and streptomycin-resistant strains of the 52,52A,80,81 phagetype complex dominated around 1960 and were replaced by multiresistant strains of the 83A complex during 1965-1975. Since then the majority of the strains have been resistant to penicillin only, firstly due to an increased occurrence of the 94,96 complex followed by strains of type 95 and group II. Today only 0.2-0.3% of the strains are multiresistant and often originate from patients hospitalized abroad. In the first half of the observation period strains from hospitals were more antibiotic-resistant and dominated by special phagetypes compared to community-strains, today there are no differences. Hospital outbreaks with S. aureus have in recent years only rarely been detected in Denmark and phagetyping results might indicate that today patients are mainly infected by their own strain. In the future, infection control and surveillance of antibiotic resistance and phagetypes should be continued together with new studies on carriage and foreign body infections.

Bacteriophage Typing↗
PubMed1994

Hepatitis A vaccine. A new convenient single-dose schedule with booster when long-term immunization is warranted.

A total of 162 anti-HAV-negative healthy adults were immunized with a single high dose (1440 ELISA units = 1 ml) of inactivated hepatitis A vaccine and a booster was given at month 6. Antibodies were measured after modification of a commercial ELISA kit, enabling quantification of titres down to 6 mIU ml-1. After 14 days, 96% of vaccinees had positive anti-HAV titres (> 20 mIU ml-1), and after 30 days all vaccinees had seroconverted. The geometric mean titres were 150 mIU ml-1 and 380 mIU ml-1 respectively. The booster dose at month 6 elicited a dramatic (25-fold) increase in antibody titres from 125 to 3090 mIU ml-1. Thus a single dose may be a convenient alternative to immunoglobulin for inducing rapid seroprotection, with a booster dose at month 6 ensuring long-lasting protection.

Adolescent↗
PubMed1992

The disappearance of multiresistant Staphylococcus aureus in Denmark: changes in strains of the 83A complex between 1969 and 1989.

During the 1960s multiresistant strains of Staphylococcus aureus were problematic in Denmark and other countries. An analysis of the phage types and antibiotic resistance patterns of S. aureus strains collected from approximately 20,000 Danish patients per year has given us a general picture of the evolution of S. aureus in Denmark during the last 30 years. Multiresistant S. aureus (i.e., strains resistant to penicillin, streptomycin, and tetracycline and often to methicillin and erythromycin as well) belonged mostly to the 83A complex, a relatively homogeneous subset of group III strains that can be further divided into six subtypes. The disappearance of multiresistant strains in Denmark began with a decline in the frequency of isolation of the most resistant subtypes, which was followed by a gradual decrease in the resistance of all 83A subtypes; thus strains of the 83A complex ultimately became no more resistant than other strains. As the proportion of strains of S. aureus accounted for by the 83A complex declined from 24% in 1969 to 6% by the late 1980s, this complex was replaced by strains of type 95, the 94,96 complex, and group II, all of which only rarely show resistance to multiple agents.

Anti-Bacterial Agents↗
PubMed1992

Killing curve activity of ciprofloxacin is comparable to synergistic effect of beta-lactam-tobramycin combinations against Haemophilus species endocarditis strains.

Nine Haemophilus species strains, all beta-lactamase negative, isolated from patients with endocarditis were tested in killing curve experiments. Antibiotics used were penicillin, amoxicillin, aztreonam alone and in combination with tobramycin, as well as ciprofloxacin alone. Synergism between beta-lactams and tobramycin with reduction of colony counts to zero was seen after 24 h for H. influenzae, H. parainfluenzae and H. segnis strains. Ciprofloxacin was as effective as beta-lactam-tobramycin combinations. The H. aphrophilus strain was not killed as effectively as other strains by any of the antibiotics.

Anti-Bacterial Agents↗
PubMed1991

Evolution of Staphylococcus aureus resistance to erythromycin in Denmark, 1959 to 1988: comparison with erythromycin-susceptible strains.

Between 1959 and 1988, all Staphylococcus aureus strains (15 168 patients) isolated from blood in Denmark have been collected, investigated and stored, and clinical data has been obtained. Erythromycin resistance was found in 4.9% of these strains. The frequency of erythromycin resistance peaked at 25% in 1966, due to the spread in hospitals of multiresistant strains of the 83A complex. When these strains dominated, an increased mortality rate was seen in patients infected with erythromycin-resistant S. aureus. In contrast to most countries, erythromycin resistance in S. aureus declined to less than 5% in 1971, continued to fall to 1.3% in 1983, and has increased slowly to 2.4% in 1988. The decline was only due to a decrease of multiresistant strains. Erythromycin-resistant strains isolated in recent years are predominantly resistant only to penicillin and erythromycin and belong to many different phage type patterns. In Denmark, inducible resistance has occurred at a stable high frequency of approximately 90% of the erythromycin-resistant strains during the last 30 years. Erythromycin-resistant strains isolated today, however, have higher minimum inhibitory concentrations, and are rarely resistant to spectinomycin, in contrast to the strains isolated in the first half of the observation period.

Denmark↗
PubMed1991

Evolution of Staphylococcus aureus resistance to erythromycin in Denmark, 1959 to 1988: correlations between characteristics of erythromycin-resistant bacteraemia strains.

In an attempt to characterize erythromycin-resistant Staphylococcus aureus we present the intricate relationships between the following factors: phage type, period of isolation, antibiogram, minimum inhibitory concentration (MIC) to erythromycin, inducible or constitutive resistance, spectinomycin susceptibility, hospital- or community-acquired infection, and mortality rate. We studied 718 cases of bacteraemia with erythromycin-resistant S. aureus, occurring between 1959 and 1988. Central factors were phage type pattern, period of isolation, and antibiogram. Between 1959 and 1973 the majority of the erythromycin-resistant strains were multiresistant and belonged to the 83A complex and the related group III. They were mainly inducibly resistant, spectinomycin resistant, and had intermediate MICs (1-4 mg l-1) to erythromycin. The majority of these strains came from hospital-acquired infections and still exist today, although in decreased numbers. By contrast, erythromycin-resistant S. aureus isolated in recent years are usually co-resistant only to penicillin and more rarely also to tetracycline. These strains have inducible resistance, are spectinomycin susceptible, and have a high erythromycin MIC. They are isolated both from hospital- and community-acquired infections. Strains with constitutive resistance to macrolides occurred at a stable low level (13%) during the whole observation period and always had high MICs to erythromycin. The mortality rate among patients with S. aureus bacteraemia due to an erythromycin-resistant strain was only associated with the year of infection and decreased from 61% in the first 15-year period to 40% in the subsequent 15 years.

Bacteriophage Typing↗
PubMed1991

Fatal septicaemia with Selenomonas sputigena and Acinetobacter calcoaceticus. A case report.

A 38-year-old man with a history of alcohol abuse developed rapidly fulminating septicaemia and died. Selenomonas sputigena and Acinetobacter calcoaceticus were isolated from a blood culture. Selenomonas sputigena is a motile anaerobic gram-negative rod rarely associated with systemic disease. Difficulties in isolation and taxonomic identification are discussed.

Acinetobacter↗
PubMed1990

Extracorporeal shock wave lithotripsy of kidney stones does not induce transient bacteremia. A prospective study. The Copenhagen Extracorporeal Shock Wave Lithotripsy Study Group.

During 58 extracorporeal shock wave lithotripsies 161 blood cultures were drawn to evaluate the incidence of bacteremia during the procedure. Only 3 blood cultures drawn during the procedure yielded bacteria, in all cases probably skin flora contaminants. Post-lithotripsy fever was noted in 29% of the patients, and could not be associated with transient bacteremia and was not influenced by antimicrobial prophylaxis. Patients with a positive urine culture after extracoporeal shock wave lithotripsy may have an increased risk of septicemia.

Adult↗