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Biomedical subjects

U Ullmann

Publications and source records attributed to U Ullmann.

At least 127 records · Page 7Linked to original sources
PubMed1977

Antibacterial activity of ticarcillin, tobramycin and gentamicin alone and in combination against Pseudomonas aeruginosa in vitro.

Using the biophotometer with ticarcillin no persistent bactericidal effect was found against Pseudomonas aeruginosa NCTC 10490. After addition of 1.2 microgram/ml gentamicin an increase of multiplication of bacteria was observed, but not after 1.2 microgram/ml tobramycin. With 6.2 microgram/ml tobramycin bactericidal effects lasted more than 24 h. In tube dilution test with Isotonic Sensi-test Broth out of 109 examined strains 51% were resistant to gentamicin, 16% to tobramycin and 4.5% to ticarcillin. If MIC values of gentamicin and tobramycin were calculated for magnesium-free media the resistance rate would be 10% for gentamicin and 3% for tobramycin. Combining subinhibitory doses of gentamicin or tobramycin with ticarcillin, most of the strains resistant to gentamicin and tobramycin became susceptible. The rate of inactivation of tobramycin by ticarcillin depends on the fluid into which they are placed. In combination therapy both antibiotics should be applied separately and immediately one after the other.

Anti-Bacterial Agents↗
PubMed1977

[The growth curves of enterobacteriaceae and the estimation of L-forms under the influence of cephalosporin antibiotics].

The antibacterial effectiveness of cephalothin, cefazolin, cephacetrile and cephradine was investigated on growing cultures of Klebsiella pneumoniae recording the growth curves with a biophotometer. Thereby cefazolin has a greater antibacterial activity than the other cephalosporins. By raising the dose to 100 microgram/ml after initial bactericidal effect a second growth phase was observed. Phase microscopic observation showed that this was caused by an increasing number of L-forms. This phenomenon could be observed with two other strains and seems to be a strain-specific characteristic. It occurs only using cephalosporins and isotonic nutrient media. The medical importance of the described ability of some bacteria as a factor of pathogenicity is discussed.

Cefazolin↗
PubMed1977

[Bacteria and resistance patterns in bacteriuria of hospitalized patients (author's transl)].

During different periods in 1976 and 1977 the bacteria of hospitalized patients were selected at random in significant bacteriuria. The species determination was carried out exactly and the susceptibility to beta-lactam-and aminoglycoside antibiotics was investigated using the quantitative tube dilution test. The bacterial spectrum of 941 isolated strains is shown in Table I. E. coli was found in 50% only. The spectrum of bacteria is different in the various hospitals, caused by regional phenomenons of nosocomial infections (Table II). The sex distribution (Table III) shows that mostly E. coli and Strept. faecalis are isolated from women, and Klebsiella sp. from men. The difference is significant. May be there exists a sex specificity for some bacteria. The sensitivity tests include the antibiotics Ampicillin, Carbenicillin, Ticarcillin, Mezlocillin, Azlocillin, Cefalotin, Cefamandole, Cefazolin, Gentamicin, Tobramycin and Amikazin (Table IV). Different sensitivity patterns could be established because of the exact species determination.

Aminoglycosides↗
PubMed1976

[Biochemical and serological investigations of flagellae of Campylobacter fetus (author's transl)].

Flagellae of Campylobacter fetus group O, types 1, 2 and 7 were prepared. First they were separated from cell bodies using an ultramix. The suspension was then centrifuged for 20 mins. at 10000 rpm and the supernatant frozen at -40 degrees C. This is a simple method for the enrichment of preparations of flagellae, as they become tangled up and accumulate in the inferior third part of the frozen liquid. The physicochemical basis of this phenomenon was discussed. After thawing and spinning for 20 mins. at 5000 rpm, the sediment was suspended in 0.9% of NaC1. The purity of the preparation was checked by electron microscopy. Antibodies to this antigen showed no cross-reaction with O-Antigen, when tested by tube agglutination. The amino acid composition of flagellae from different O-antigen serotypes was different (see Tab. 1). Cysteine could not be detected and proline only in traces. After breakdown with urea followed by gel filtration on Sephadex G 200, breakdown products of diminishing molecular size were obtained (see Fig. 2). Discelectrophoresis after ultrasonic gave 8 zones (see Fig. 3). Irrespective of serotype, thin-layer chromatography of trypsin-hydrolysed flagellae always showed 9 ninhydrin-positive spots (see Fig. 1). Only breakdown products of ultrasonic reacted with antibody. After absorption of flagellar antibody with heterologous antigen, agglutination only occurred with homologous antigen (tab. 2-5). This showed that there were different flagellar antigens. Further experiments using immunoprecipitation demonstrated two common antigenic components, a and c, and a partially common antigenic factor bb (Fig. 4), and was the basis for a classification by three groups. The three antigenic components could be separated by gel electrophoresis and detected by immunoprecipitation (Figs. 5,6).

Agglutination Tests↗
PubMed1975

[The bacteriological diagnosis of vibrio fetus infection in man (author's transl)].

A synopsis of the present classification of Vibrio fetus is given (tab. 1, 2). Besides the presentation of the importance of these bacteria in veterinary medicine, 97 human infections have been published up to now. The geographic, age and sex distribution of these cases and the material out of which the pathogens were isolated is presented (tab. 3, 4). The clinical picture is summarized. For the culture of Vibrio fetus liver broth as described by TAROZZI incubated for at least 3-4 days was suitable as enrichment medium. The necessity of a prolonged incubation period was shown by results of continous registration of the optical density of growing Vibrio fetus cultures (fig. 1). If specimen is plated out on solid culture media before enrichment, the suitable media are chocolate agar, brain-heart infusion and Bacto-tryptose agar. For subcultures the DST-agar is also useful. Solid media cultures should be incubated microaerobically with 10% CO2 added. The resistance to Cephalothin of Vibrio fetus can be applied for selection on solid culture media. The metabolic activities of different Vibrio fetus biotypes were compared. A hitherto not reported metabolic activity, the hydrolysis of palmitic acid ester, is described (tab. 5). In the tube dilution test Vibrio fetus strains were sensitive to Gentamycin, Streptomycin, Ampicillin, Ciclacillin and Carbenicillin. They were resistent to Penicillin G, Cephalotin and Sulfonamid and showed borderline sensitivities to Tetracyclin, Kanamycin and Chloramphenicol (tab. 6).

Ampicillin↗
PubMed1975

[Bacteriological investigations and animal experiments with Mycobacterium ulcerans (Tübingen 1971) (author's transl)].

In 1972 we reported the first isolation of M. ulcerans in Germany and in 1973 we reviewed the epidemiology, clinical features and therapy of Buruli ulcer (6, 7). Initial isolation was done from swabs of the edge of the ulcer on Loewenstein-Jensen medium at 30-33 degrees C. Subcultures showed poor growth at 37 degrees C, and none at 22 degrees C or 42 degrees C or on Loewenstein-Jensen medium without glycerine. No acylamidase or lipolytic activity was detectable and the organisms were catalase positive, triphenyltetrazolium chloride reduction positive, nitrate reduction negative and nicotinic acid production positive (Table 2). Possibly our strain is a nicotinic acid positive variant, as is the strain described by RUNYON et al. (16). (The bacteriological characteristics are summarized in Table 2). Our strain was sensitive to dihydrostreptomycin, cycloserine, viomycin, rifampicin and a riminophenacin derivate (Lampren), but was resistent to isoniazid, para-aminosalicyclic acid, ethionamid and ethambutol (Table 3). White mice and rats but no guinea pigs are susceptible to infection with M. ulcerans. Injection into the foot pad is preferable to intraperitoneal or subcutaneous injection (Table 4). After such an injection of material from our patient, signs of disease appeared in the following order: 1. foot pad swelling; 2. redness and oedema of the whole leg; 3. ulceration of the dorsum of foot (fig. 1) with fluctuant, gross oedema of the subcutaneous tissue and loss of hair; 4. atrophy and contraction of the infected extremity with the development of further ulceration on the abdomen and tail. In the two months following an injection of a standard suspension of M. ulcerans the animals developed such gross oedema of the subcutaneous tissues of the abdomen that its progression could be followed by regular weighing (fig. 2). By the end of the two months, the total body weight was double that of control uninfected animals.

Animals↗
PubMed1975

[In vitro experiments on the working of combinations of gentamicin and beta-lactam antibiotics against Pseudonomas aeruginosa (author's transl)].

The M.B.C.'s of gentamicin and carbenicillin against Pseudonomas aeruginosa NCTC 10490 were measured under controlled conditions using a Biophotometer. The M.B.C. of gentamicin was 15 mug/ml but even in a concentration of 1,000 mug/ml carbenicillin was not bactericidal. In further experiments, subinhibitory concentrations of gentamicin (1 mug/ml) together with varying concentrations of carbenicillin were added to a log phase culture of the organism. Under these conditions the M.B.C. of carbenicillin was now 6 mug/ml. In tube dilution test the M.B.C. of carbenicillin alone was 15.6 mug/ml and for gentamicin 3.9 mug/ml. The M.B.C.'s of other beta-lactam antibiotics (ampicillin, penicillin G and cephalothin) were four to five times as great as for carbenicillin whereas that for ticarcillin was identical. Parallel to the "multiplication inhibition" test in the Biophotometer we investigated 51 strains of Pseudomonas aeruginosa freshly isolated from clinical material. Their M.B.C.'s were determined in tube dilution tests against doubling dilutions of beta-lactam antibiotics, with and without the addition of 1 mug/ml gentamicin. With this concentration of gentamicin, the M.B.C.'s of carbenicillin and ticarcillin were considerably lower than for these substances alone. In comparison to carbenicillin, ticarcillin was more effective against Pseudomonas aeruginosa. Our findings indicate that for Pseudomonas aeruginosa infections the combination of gentamicin with other beta-lactam antibiotics (ampicillin, penicillin G and cephalothin) is to be avoided. But the combination of gentamicin with either carbenicillin or ticarcillin appeared to be effective.

Bacteriological Techniques↗