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Biomedical subjects

J Wüst

Publications and source records attributed to J Wüst.

At least 55 records · Page 3Linked to original sources

[Micrococcus luteus: a rare pathogen of valve prosthesis endocarditis].

A rare case of prosthetic valve endocarditis caused by Micrococcus luteus is described and compared with the few cases reported in the literature, as well as the clinical features, microbiological profile, therapy, and prognosis of common prosthetic valve endocarditis. Micrococcus luteus is a constituent of the normal human buccal bacterial flora which forms yellowish colonies and appears as a gram-positive coccus typically arranged in tetrades. Although of low virulence, the germ may become pathogenic in patients with impaired resistance, colonizing the surface of heart valves. In contrast to staphylococci (for which it may easily be mistaken) it is usually penicillin-sensitive. However, the most promising antibiotic regimen proposed for treatment of Micrococcus luteus seems to be a combination of vancomycin, amikacin, and rifampicin. If the infection leads to severe hemodynamic alterations, however, valve replacement may become necessary similar to the situation in prosthetic valve endocarditis caused by more aggressive and highly resistant bacteria.

Aged↗

[Classical pseudomembranous diphtheria caused by Corynebacterium ulcerans].

In a 63-year-old patient presenting with signs of classical diphtheria including membranous pharyngotracheobronchitis and myocarditis, Corynebacterium ulcerans was isolated in pure culture from the membranes. The strain produced a toxin specific for C. ulcerans but no diphtheria toxin. The patient was discharged after a complicated hospital course including respiratory and cardiac failure. Besides Corynebacterium diphtheriae, which has very rarely been isolated in Switzerland in recent years, Corynebacterium ulcerans should be considered as a cause of classical diphtheria.

Bacterial Toxins↗

Experience of gas-liquid chromatography in clinical microbiology.

In clinical microbiology, gas-liquid chromatography (GLC) is used mainly for the following applications: (1) demonstration of microbial metabolites in cultures: studies of short-chain fatty acids (chain length 2 to 6 carbon atoms) and of the non-volatile lactic and succinic acids are the basis of taxonomy of obligate anaerobes on the genus level. Demonstration of these compounds in spent culture media is also used for identification of anaerobic bacteria in the clinical laboratory. (2) Investigation of long-chain fatty acids of cell membranes and the cell wall: analysis of fatty acids with chain lengths of 9 to 20 carbon atoms are used primarily for taxonomic purposes. A practical application for use in clinical bacteriology is the Microbial Identification System (MIS) based on equipment built by Hewlett-Packard. Although this system is excellently suited for quantitative analysis of long chain fatty acids and gives valuable preliminary or confirmative information, it often requires additional testing for identification of bacteria to species level. (3) Direct rapid diagnosis of infection: demonstration of metabolic products in body fluids can be of value in infections with anaerobes (demonstration of fatty acids) and yeasts (sugars). GLC combined with mass spectrometry or frequency-pulsed electron capture GLC techniques have been applied to studies of sera, fecal specimens, and cerebrospinal fluids. These latter applications are still in an experimental stage. However, the rapid diagnosis of tuberculosis directly from cerebrospinal fluid and sputum is well advanced. The potential of direct diagnosis without the resort to cultures warrants continued research with these techniques.

Bacteria, Anaerobic↗

[Bacterial susceptibility to chemotherapeutic agents (Zurich, 1987)].

This paper describes the frequency of susceptibility of Gram-positive and Gram-negative bacteria against antibacterial agents. The data are based on all susceptibility tests performed at the Department of Medical Microbiology of the University of Zurich. The evaluation of the results from 1975 to 1987 shows that susceptibility against standard antimicrobial agents has not decreased in this period. These tables may be a valuable help for the physician in his decision for a "calculated chemotherapy".

Anti-Bacterial Agents↗

[Campylobacter pylori colonization of the antrum: effect of gastrin, somatostatin, pancreatic polypeptide and neurotensin].

Campylobacter pylori (C.p.) infection is often found in patients with antral gastritis and peptic ulcer disease. Pathophysiological links are still unclear, and we therefore tested the hypothesis whether C.p. affects the gastrointestinal peptides and thus influences gastric acid secretion and protective factors. 94 patients were examined by upper GI endoscopy and blood analyzed for gastrin, somatostatin, pancreatic polypeptide and neurotensin. Biopsies of antral mucosa were investigated for C.p. in urease testing, culture and microscopy. C.p. was found in 42 patients (45%). In microscopy all of these patients had chronic gastritis (100%). A significant increase in gastrin uninfluenced by C.p. was found in patients with antral gastritis (normal: 6.4 +/- 0.7, [n = 27]; gastritis without C.p.: 18.4 +/- 5.9 [p less than 0.02], [n = 7]; gastritis with C.p.: 10.7 +/- 2.2, [n = 22]). Somatostatin, pancreatic polypeptide and neurotensin showed no difference.

Campylobacter↗

[Rhodococcus equi infection in HIV disease].

A case of Rhodococcus equi pneumonia associated with septicemia and metastatic brain abscess in an HIV-infected male is presented. Clinical findings and the diagnostic and therapeutic approach are discussed. Cavitating pulmonary disease was rapidly improved by six-week combined oral and parenteral antibiotic treatment. However, pulmonary relapse and brain abscess were documented after one month. Therapy with ceftriaxone, ciprofloxacin and cotrimoxazole on an outpatient basis again led to clinical and radiological improvement after four weeks. Surgical resection of localized processes should be considered early, and prolonged antibiotic therapy over months is recommended.

Acquired Immunodeficiency Syndrome↗

Clinical efficacy of amoxycillin/clavulanate in laparoscopically confirmed salpingitis.

To test the efficacy and safety of amoxycillin/clavulanate (Augmentin), 102 hospital patients with laparoscopically confirmed acute salpingitis were treated with parenteral amoxycillin/clavulanate (1.2 g qid for three days) followed by oral amoxycillin/clavulanate (two tablets of 625 mg tid for a further six days). Bacteriological samples were obtained from the cervix uteri and the pouch of Douglas. One hundred patients were assessable for clinical outcome using several variables including pain scores. Amoxycillin/clavulanate alone was effective in 95 patients (95%). Three patients (3%) responded to amoxycillin/clavulanate with marked improvement but another antibiotic was subsequently added to their treatment regimen. Treatment failed in two patients. At follow-up two weeks after hospital discharge, three patients (3.8%) had relapsed or were re-infected. Adverse drug events included one case of drug fever, one case of rash and one case of severe diarrhoea. Treatment was stopped in all three cases. Gastrointestinal reactions, mainly mild diarrhoea, were seen in 31 patients. No clinically relevant changes in haematological or clinical chemical indices were attributable to the amoxycillin/clavulanate treatment. We conclude that amoxycillin/clavulanate is a clinically effective and safe treatment for acute salpingitis.

Acute Disease↗

[Sensitivity determinations for mycobacteria, fungi, anaerobic and other presumptive bacteria].

The indications and methods for sensitivity testing of mycobacteria, fungi, anaerobes, and other fastidious bacteria are described in a study which is part of a series on sensitivity testing (this journal, 1984; 114: 1079-1086 and 1987; 117: 509-517). Since these tests are rarely indicated and involve methodological problems, they are best performed by larger laboratories or by reference units.

Anti-Bacterial Agents↗

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↗

Branhamella catarrhalis: fatty acid and lipopolysaccharide analysis of an atypical strain from blood culture.

A Branhamella catarrhalis-like organism was isolated from blood cultures; it was atypical in showing negative nitrate and nitrite and positive gamma-glutamylaminopeptidase reactions, in agglutinating with Neisseria meningitidis antisera, and in forming butyrous colonies. Cell-wall fatty-acid and lipopolysaccharide analysis provided evidence that this isolate was an atypical B. catarrhalis.

Bacterial Infections↗

Identification of contaminants during primary isolation of mycobacteria in the BACTEC system with the antimicrobial supplement PACT.

1500 sputum specimens and bronchial washings were cultured for mycobacteria. One half of the specimen was treated with N-acetyl-L-cysteine--sodium hydroxide (3%) (NALC) and the other with sodium dodecyl (lauryl) sulfate--sodium hydroxide (1%) (SDS). The different species of contaminants found with each pretreatment method with the BACTEC radiometric system were identified. Contamination occurred in 6% by using SDS and in 10% by using NALC. The SDS method was more effective against Bacillus ssp. and Streptomyces ssp., the major contaminants. However, the growth of Pseudomonas ssp. was a problem in both methods.

Acetylcysteine↗

Studies on the resistance of Clostridium difficile to antimicrobial agents.

The susceptibility of C. difficile isolated at the Department of Medical Microbiology of the University of Zurich to a wide selection of antibacterial, antimycobacterial and antifungal agents was tested in vitro. Great differences in susceptibility were found against chloramphenicol, clindamycin, erythromycin, rifamycin, and tetracycline. Resistance to clindamycin and erythromycin could always be transferred jointly to a susceptible C. difficile strain by mixed culture on filters at low frequencies (1 X 10(-8) to 4 X 10(-8) per donor cell). Transfer of tetracycline resistance occurred at frequencies of 3 X 10(-7) to 5 X 10(-7). Chloramphenicol and rifamycin resistance could not be transferred in the system used (frequencies less than 10(-8)). Although a total of 38,000 colonies was screened by various methods known to affect plasmid replication, resistance to chloramphenicol, clindamycin, erythromycin, rifamycin, and tetracycline could not be eliminated. No connection between plasmid DNA and antimicrobial resistance could be established. Especially, no plasmid DNA was involved in the transfer of resistance determinants from resistant to susceptible strains.

Anti-Bacterial Agents↗

[Experiences in the diagnosis of lower respiratory tract infection using a double-sheathed brush catheter].

Specimens from the lower airways were taken by protected brush catheter during 54 fiberoptic bronchoscopies for quantitative microbiological analysis. This technique allows uncontaminated sampling of lower airway secretion. The chance of identifying a bacterial pathogen in patients who have already been treated with antibiotics was less than 10%. The method is cumbersome, and it is important not only to culture but also to quantify the bacteria. The microbiological results thus obtained have influenced clinical decision-making in only a few patients.

Bacteria↗

[Antibiotic resistance and serotypes of Streptococcus pneumoniae in Zurich (1984-1985)].

We have investigated the serotypes and sensitivity of 133 pneumococci against 11 antimicrobial agents in the agar dilution test. The strains had been isolated from clinical specimens sent to the Department of Medical Microbiology of the University of Zurich during 1984 and 1985. - Three strains (2.3%) had reduced sensitivity to penicillin G. 23 strains (17.3%) showed resistance or reduced susceptibility to tetracycline, one strain each (0.8%) to amoxycillin and cefaclor, and two strains each (1.5%) to erythromycin and sulfamethoxazole/trimethoprim. All pneumococcal strains investigated were susceptible to ceftazidime, ceftriaxone, chloramphenicol, vancomycin and ciprofloxacin. In view of this situation, routine testing of all clinically significant pneumococci is to be recommended. However, in the agar diffusion test the use of a penicillin G disk is unreliable and may give results with false sensitivity. Therefore, the susceptibility test should be performed with a disk containing oxacillin. - The prevalent capsular serotypes were - in descending order - types 3, 6, 23, 19, 14, 7, 8, 9, 1, and 17. 90.2% of the isolated pneumococci belonged to serotypes which are contained in the new vaccine "Pneumovax-23".

Amoxicillin↗