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W Heizmann

Publications and source records attributed to W Heizmann.

At least 19 recordsLinked to original sources
PubMed1990

In vitro activity of daptomycin-metronidazole combinations against mixed bacterial cultures: reduced activity of metronidazole against Bacteroides species in the presence of Enterococcus faecalis.

The in vitro activity of daptomycin-metronidazole combinations against mixed cultures of gram-positive facultative cocci and strains of the Bacteroides fragilis group was investigated. Metronidazole did not influence the high activity of daptomycin against strains of Staphylococcus aureus, Staphylococcus epidermidis and Enterococcus faecalis in the absence or presence of the co-cultured Bacteroides strains. In contrast, the Enterococcus faecalis isolates protected the co-cultured Bacteroides strains against the killing effect of metronidazole, even at a concentration four- or eightfold the MIC of metronidazole. Killing curve experiments confirmed this protective effect of different isolates of Enterococcus faecalis.

Anti-Bacterial Agents↗
PubMed1989

[Uses and advantages of a computer-assisted microbiologic diagnosis and database system for antibiotic therapy in surgery].

To demonstrate the value of a computer assisted microbiological diagnosis and database system for clinical use, epidemiological aspects of three important infections were investigated: urinary tract, respiratory tract and wound infections. The first two examples presented revealed significant differences in incidence of pathogens between a single patient group and the overall statistic. The third example demonstrates that even within a department susceptibility patterns of staphylococcus epidermidis were changing in dependence of the ward investigated. In the last example the evaluation of susceptibility testing revealed changing patterns of some pathogens during the observation periods. By means of a computer assisted diagnosis and database on file at the moment of diagnosis thus allowing statistical evaluations at every time within a few hours. The clinician provided with actual data concerning his ward or department may administer an empiric therapy according to the real situation. Besides this, automated susceptibility testing may shorten the time required for diagnosis up to 24 h, thus further contributing to a more rational antimicrobial therapy. In conclusion computer assisted diagnosis and automated instruments support the clinician by means of actual epidemiological data and rapid reporting in choosing and controlling antimicrobial therapy.

Anti-Bacterial Agents↗
PubMed1988

Evaluation of the Cobas Bact automated system for susceptibility testing of Enterobacteriaceae, Pseudomonas aeruginosa, and Enterococcus faecalis to azlocillin, mezlocillin, and ciprofloxacin compared to NCCLS and DIN standards.

The aim of automated susceptibility testing systems like the Cobas Bact is to provide the clinicians with rapid and reliable results for the care of patients and to decrease the work load in microbiological laboratories. Because data about accuracy on mezlocillin, azlocillin and ciprofloxacin were lacking, we investigated 184 bacterial strains and compared the results of the Cobas Bact susceptibility testing to standardized agar dilution and agar diffusion methods. Essential correlations for all methods compared exceeded 90% for the three chemotherapeutics and all species investigated, with the exception of Pseudomonas aeruginosa. On an average only 1.5% very major errors were observed with the several species of Enterobacteriaceae, whereas P. aeruginosa and Enterococcus faecalis were characterized by the complete absence of very major errors when Cobas Bact was correlated to NCCLS agar diffusion.

Autoanalysis↗
PubMed1988

New developments in medical microbiology: computer-assisted diagnosis and automated instruments.

Time and accuracy required for diagnosis are two of the most important factors in medical microbiology. Computer-assisted diagnosis is one tool to overcome these problems. The software of such systems, much more than the hardware, is of utmost importance and both have to fulfill several items. 1) High flexibility and integration within the already existing working schemes of the laboratory. 2) Terminals in every laboratory. 3) High speed of calculation. 4) Online data transfer from automated instruments. 5) External terminals on intensive care units. 6) Epidemiological and etiopathological investigations have to be possible at any time. In the laboratory the burden of simple, repeating tasks is diminished, inquiries can be made in a minute and precise information about the epidemiological situation can be gained within a few hours. Thus, calculated antimicrobial therapy depending on the incidence of certain pathogens in given specimens in different departments is possible. In the case of fast-growing bacteria, preliminary reports, including susceptibility testing available within the first 24 h, are possible and will be of great help to the clinician in monitoring the calculated antimicrobial regimen. External terminals will allow continuous flow of data from the laboratory to wards and vice versa.

Autoanalysis↗
PubMed1988

Benefit and advantage to clinicians of a computer-assisted microbiological diagnosis and database system.

Computer-assisted diagnostic systems may accelerate transmission of microbiological reports and facilitate evaluation of the epidemiological situation and thus improve the collaboration between microbiologists and clinicians. This possible benefit is demonstrated by four examples. It became evident that incidences of pathogens in urinary tract and respiratory tract infections varied within a great range, depending on patient groups and clinical departments involved. Even within a department, different incidences of penicillin G and oxacillin-resistant coagulase-negative staphylococci were demonstrated. An apparent homogeneity of distribution of pathogenic bacteria in a hospital tends to be the result of a nondiscriminating overall evaluation, thus necessarily misleading the clinician especially in empirical chemotherapy. In the last example the evaluation of susceptibility testing revealed changing patterns of some pathogens during the observation period. By rapid exchange of data between the laboratories and the clinical departments supplying the clinicians with information relevant for actual therapeutical decisions, an empiric therapy may change into a so-called calculated therapy based upon data directly related to the site of infection, department and susceptibility patterns.

Diagnosis, Computer-Assisted↗
PubMed1988

Comparison of the Cobas-Bact five-hour susceptibility testing system with the NCCLS agar diffusion and dilution methods.

The results of susceptibility tests performed by the Cobas-Bact system were compared with those of the NCCLS agar diffusion (Kirby-Bauer) and NCCLS agar dilution methods. A total of 998 clinical isolates were tested against 10 to 18 antimicrobial agents. Essential agreement (comprising full agreement and minor discrepancies) varied from 90.5% to 99.2% on comparison of Cobas-Bact with Kirby-Bauer results, depending on the bacterial group (mean for all 998 strains tested 95.7%). These figures ranged from 91% to 99.2% (mean 96.3%) for the Cobas-Bact/MIC comparison and from 95.2% to 99.7% (mean 98.7%) for the Kirby-Bauer/MIC comparison. The best results were found for Enterobacteriaceae and Staphylococcus aureus, whereas for enterococci and coagulase-negative staphylococci there was a lower rate of essential agreement in all three comparisons. In the case of Pseudomonas aeruginosa there was a good rate of essential agreement but many minor discrepancies, resulting in a disappointing rate of full agreement of between 67.5% and 78.9% in the three comparisons. The Cobas-Bact system would appear to provide satisfactory susceptibility test results in most cases, however there are still some major problems in the system which should be resolved.

Enterobacteriaceae↗
PubMed1988

Computer-aided densitometric analysis of protein patterns of Clostridium difficile.

The applicability of whole-cell protein patterns obtained by sodium dodecylsulfate-polyacrylamide gel electrophoresis as a typing method for Clostridium difficile was examined using a total of 227 strains isolated from 191 patients and their surroundings. Computer-aided densitometric analysis was used to establish a reliable standardization technique with which a large number of protein patterns could be efficiently classified. The normalized tracks could be electronically superimposed and compared to give reproducible results. The influence of sample preparation for electrophoresis was found to be negligible. By this technique 35 subgroups could be differentiated, and further discrimination was possible within each subgroup using minor, even very weak protein bands. Epidemiologically related strains of Clostridium difficile yielded absolutely identical patterns, allowing unequivocal identification. Thus protein electrophoresis combined with densitometric analysis was shown to be useful for typing Clostridium difficile isolates.

Bacterial Proteins↗
PubMed1988

Comparison of four commercial microdilution systems for susceptibility testing of anaerobic bacteria.

The reliability of four commercially available broth microdilution systems (ATB ANA, MHK-Anaerob-Biotest, Dynatech MIC system, Sceptor Anaerobe MIC system) for routine susceptibility testing was evaluated using agar dilution and broth macrodilution as reference methods. Using the categories "susceptible", "moderately susceptible" and "resistant", the rate of essential agreement (complete agreement plus minor errors) of all four systems compared to the two reference methods was satisfactory, ranging from 93% (Dynatech system and agar dilution) to 98% (Sceptor system and agar dilution). The rate of complete agreement compared to the agar dilution and broth dilution method respectively was 61% and 60% for the MHK-Anaerob-Biotest, 65% and 63% for the Dynatech system, 72% and 72% for ATB ANA, and 85% and 80% for the Sceptor system. The Sceptor system was thus superior to the other systems. The systems were easy to operate and inoculate, although arrangement of antimicrobial agents in the Dynatech panels was apt to be confusing.

Bacteria, Anaerobic↗
PubMed1988

Rapid identification of Escherichia coli by Fluorocult media and positive indole reaction.

To assess the specificity and sensitivity of Fluorocult media for the identification of Escherichia coli, the beta-glucuronidase activities of 1,258 bacterial strains, as well as 20 strains of Candida spp., were investigated. Fluorescence of colonies combined with positive indole reaction resulted in specificities of 99.6 to 99.8%. Sensitivities were 59.1% (MacConkey agar), 69.9% (brolacin agar), 85.5% (Columbia agar), and 85.8% (ECD agar).

Enterobacteriaceae↗
PubMed1988

[The effect of a combination of ampicillin and sulbactam against clinical anaerobic isolates].

Effect of a Combination of Ampicillin and Sulbactam on Clinical Isolates of Anaerobic Bacteria. The antimicrobial susceptibility of 182 recent clinical isolates of anaerobic bacteria to ampicillin alone, ampicillin plus 1 mg/l sulbactam, ampicillin plus 5 mg/l sulbactam, and cefoxitin was studied by means of agar dilution tests. The ampicillin-sulbactam combination (Unacid) was most effective against species of the Bacteroides fragilis group, the MIC90 of ampicillin plus 5 mg/l sulbactam for B. fragilis being less than or equal to 1 mg/l, compared to 256 mg/l of ampicillin, 4 mg/l of ampicillin plus 1 mg/l sulbactam, and 8 mg/l of cefoxitin. No significant difference between ampicillin alone and in combination with sulbactam was observed against gram-positive anaerobic rods or cocci.

Ampicillin↗
PubMed1988

In vitro activity of flomoxef compared to moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes.

To assess the in vitro activity of flomoxef (6315-S), moxalactam, cefoxitin, cefotaxime, and clindamycin against anaerobes 197 clinical isolates (27 Bacteroides fragilis, 42 B. thetaiotaomicron, 10 B. vulgatus, 7 B. ovatus, 6 B. uniformis, 6 B. distasonis, 7 Bacteroides melaninogenicus group, 11 Bacteroides oralis group, 21 Clostridium difficile, 7 C. perfringens, 3 C. sporogenes, 3 Clostridium spp., 33 Propionibacterium acnes, 14 Peptococcaceae) were studied by means of agar dilution tests. The MIC90 of B. fragilis was less than 2 micrograms/ml for flomoxef, less than 4 micrograms/ml for moxalactam, less than 16 micrograms/ml for cefoxitin, less than 128 micrograms/ml for cefotaxime and less than 2 micrograms/ml for clindamycin. The respective MIC90's of B. thetaiotaomicron were less than 64, less than 128, less than 32, less than 256 and 8 micrograms/ml. Strains of the other Bacteroides species and groups were more susceptible to flomoxef and the other antibiotics than B. thetaiotaomicron. Against Clostridium difficile flomoxef (MIC90 less than 4 micrograms/ml) proved to be superior to the other agents tested. Most of the Clostridium strains other than C. difficile were also susceptible to flomoxef; anaerobic grampositive cocci and Propionibacterium acnes were very sensitive (MIC90's less than 1 and less than or equal to 0.125 micrograms/ml, respectively). Its anti-anaerobic activity, together with its efficacy against aerobes, should make flomoxef a useful adjunct to the arsenal of modern antibiotic therapy.

Anti-Bacterial Agents↗
PubMed1987

Surveillance cultures and benefit of laminar airflow units in patients undergoing bone marrow transplantation.

The effectiveness of gastrointestinal and topical decontamination, as well as isolation in laminar airflow (LAF) units were investigated in 20 patients. On a weekly basis, surveillance cultures were taken. Environmental controls were taken on the medical ward outside the two LAF units and from the LAF unit itself when being used by a patient. The use of LAF units seems to be of benefit in preventing exogenous infections, but there are two weak points in the isolation techniques: the opening of the tent (with a free entry into the tent itself) and the water delivery system. By using appropriate decontamination measures, it was possible to greatly reduce the number of bacteria and species of the normal flora in all regions with the exception of the oropharynx. Individual patients with oxacillin resistant coagulase-negative staphylococci and/or Candida albicans continued to show the presence of these organisms during this time. The detection of Clostridium difficile and/or its toxin B in eight patients at the beginning of the individual observation period was significant. Four out of 15 fever episodes were attributable to endogenous bacterial infections. Each of the causative organisms had been previously isolated in the surveillance cultures, thus the clinician was able to initiate a calculated antimicrobial therapy. As evident from the low incidence of infectious complications, gastrointestinal and topical decontamination of the skin as well as reverse isolation in LAF units are efficient protective measures for bone marrow transplant patients.

Adolescent↗
PubMed1987

In vitro activity of ampicillin plus sulbactam against anaerobes compared to ampicillin and cefoxitin.

The antimicrobial susceptibility of 195 recent clinical isolates of anaerobic bacteria was studied to ampicillin alone, ampicillin + 1 mg/l sulbactam, ampicillin + 5 mg/l sulbactam, and cefoxitin by means of agar dilution tests. The ampicillin-sulbactam combinations were the most effective drugs against species of the Bacteroides fragilis group, the MIC90 of ampicillin + 5 mg/l sulbactam for B. fragilis being less than 1 mg/l, compared to 256 mg/l of ampicillin, 4 mg/l of ampicillin + 1 mg/l sulbactam, and 8 mg/l of cefoxitin. No significant difference between ampicillin alone and in combination with sulbactam was observed against gram-positive anaerobic rods, Peptococcus spp. and Peptostreptococcus spp. with MIC's less than 2 mg/l.

Ampicillin↗
PubMed1986

Bacterial colonization and occurrence of Legionella pneumophila in warm and cold water, in faucet aerators, and in drains of hospitals.

Warm and cold water as well as water from wash basin drains and faucet aerators was examined to determine the number of viable and dead bacteria by culture and by staining and to establish the spectrum of species with special consideration of Legionella pneumophila. The relation between the number of Legionella pneumophila, the temperature, and the iron content of the water was determined in three separate warm water systems. High colony counts (up to 8.9 X 10(5) colony-forming units), were detected in both warm and cold water at certain sampling sites. The most prevalent genera were Pseudomonas, Bacillus, Flavobacterium, Acinetobacter, and Moraxella. Legionella pneumophila was found in every building in 35 of 150 warm samples and in 1 of 43 cold water samples. The highest water temperature of a sample containing Legionella pneumophila was 64 degrees C. The correlation between high colony counts and the occurrence of Legionella pneumophila in the samples was not significant. High iron concentrations, however, appear to have a positive effect on the growth of Legionella pneumophila.

Equipment and Supplies, Hospital↗
PubMed1986

[In vitro erythrophagocytosis in detecting opsonizing antibodies in a patient with Malta fever. A hypothesis on the explanation of in vivo hemophagocytosis in other patients with Malta fever].

In vitro agglutination and phagocytosis of erythrocytes by homologous neutrophil granulocytes and monocytes could be observed using the blood of a healthy person (blood group A, Rh+) to detect opsonising antibodies in the serum of a patient with Malta fever (blood group O, Rh+). Agglutination and erythrophagocytosis were independent of complement or the presence of Brucella melitensis. In patients with Malta fever and blood groups O and B, respectively, antibodies could be detected on the surface of erythrocytes of blood group A when used as antigen with the help of an immunofluorescence test. The same happened with a serum of one patient with blood group A. In vivo erythrophagocytosis detected in the bone marrow of patients with Malta fever is, therefore, possibly due to common antigens of erythrocytes of blood group A and B. melitensis.

ABO Blood-Group System↗