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W Witte

Publications and source records attributed to W Witte.

At least 37 records · Page 2Linked to original sources
PubMed1986

Resistance to mercury and to cadmium in chromosomally resistant Staphylococcus aureus.

Apparently chromosomally located mercury resistance determinants in five methicillin-resistant Staphylococcus aureus strains of different geographical origin were structurally homologous to plasmid-located mercury resistance determinants in S. aureus. These were all located on a 6.3-kilobase (kb) Bg/II fragment, as evident from Southern hybridization experiments with the 6.3-kb Bg/II fragment of plasmid pI258 as the probe. These methicillin-resistant S. aureus strains exhibited similar phage susceptibility patterns and biochemical reactions. They differed, however, in the DNA location of the mercury resistance determinants, as evidenced by neighboring cleavage sites for restriction endonucleases EcoRI, HindIII, and PstI. In an environmental (nonhospital) strain in which mercury resistance was also apparently chromosomally conferred, these determinants were also homologous to pI258 DNA, but they were located on a 6.6-kb Bg/II fragment. Cadmium resistance determinants in the five methicillin-resistant S. aureus strains and the environmental S. aureus strain were not similar to the known plasmid-located determinants cadA and cadB. Cd2+ resistance was based on an efflux mechanism for Cd2+. However, no parallel resistance to zinc was conferred. The 3.2-kb XbaI-Bg/II fragment obtained from plasmid pI258 and used as a cadA-specific probe did not hybridize to total DNA digests of the strains with apparently chromosomally determined cadmium resistance.

Cadmium↗
PubMed1986

Methicillin-resistant Staphylococcus aureus (MRSA) in the German Democratic Republic. Incidence and strain-characteristics.

In GDR methicillin-resistance strains of S. Aureus only occur in connection with nosocomial infections with a comparably low incidence (about 2%). They are not found in outpatients. For the detection of MRSA the test on nutrient medium L4 with addition of 5% NaCl has proved successful. All of the MRSA exhibit a rather unique pattern of strain-characteristics; they are nontypable by the basic-set-phages and show a reaction with the experimental phage A 994. The MRSA are multiple drug-resistant (generally penicillins, cephalosporins, isoxyzolylpenicillins, oxytetracycline, minocycline, streptomycin, erythromycin, lincomycin and additionally chloramphenicol and gentamycin, kanamycin, tobramycin). The genetical characterization and the plasmid-pattern analysis has shown that only resistance to chloramphenicol and in one case also to macrolides are determined by plasmids (MW 2.0 and 1.8 Megadalton). The determinants for the other resistance-characters are obviously located on the chromosome. Altogether these data indicate that the MRSA described are derivatives of a single-strain-clone.

Cross Infection↗
PubMed1984

Occurrence of a nonplasmid-located determinant for gentamicin resistance in strains of Staphylococcus aureus.

The occurrence of resistance to gentamicin in strains of Staphylococcus aureus with different phage patterns in two hospitals is described. The data suggest transfer of gentamicin resistance between different strains. In the strains investigated the determinant for resistance to gentamicin (parallel resistance to kanamycin and tobramycin) is located on the chromosome. The transfer of this resistance determinant in a mixed culture of donor and recipient cells in vitro is mediated by transduction because it is dependent upon lysogenicity of the donor for a serogroup-B phage and because it can be inhibited by gamma-globulin. The transfer is always associated with lysogenization of the recipient cells by this phage.

Bacteriophage Typing↗
PubMed1981

[Role of phage in the transfer of plasmids in mixed cultures of Staphylococcus aureus (author's transl)].

Lysogenicity with phages of serogroup B is a prerequisite to the transfer of drug resistance plasmids in mixed cultures of Staphylococcus aureus. This is demonstrated by experiments with transfer of the plasmids pII 147, pC 221, pT 127, pE 2222 to strain 8325-4 which was lysogenized for different phages of different serogroups (Table 2). The transfer is also possible, when the donor strain or the recipient strain are lysogenic for the phage mutant phi 11, M 28, which is able to lyse strain 8325-4 but unable to form phage heads (Kretschmer and Egan, 1975). The fact that the induction of prophage phi 11 and steps of phage-propagation are necessary for the transfer, is evident from negative results obtained by use of the rec--mutant of strain 8325 (RN 981) as donor and by use of strain 8325-4 lysogenic for the phage mutant phi 11, A 4 as donor. The phage mutant phi 11, A 4 is defective at an early step of phage propagation. These experiments are shown in Tables 3 and 4. The possibility of transfer using donor or recipient strains which are lysogenic for a phage-mutant but unable to form phage heads clearly shows that the transfer is not based on transduction. Incubation of non lysogenic donor and recipient cells in the culture supernatant of strain 8325-4 (phi 11, M 28) or in the lysate of strain 8325-4 obtained after infection with phage phi 11, M 28 also allows the transfer of plasmids. Obviously one of the components of serogroup B phages is essential for the transfer.

Lysogeny↗
PubMed1979

[Phage typing and lysogen typing of Staphylococcus aureus].

A comparison was made between the results of phage and lysogenic typing of S. aureus strains isolated during several outbreaks of staphylococcal infection and S. aureus cultures isolated from the same carriers at different periods. The study of the groups of strains having the same origin showed that the differences in the number of reactions were more pronounced in lysogenic typing than in phage typing. For this reason lysogenic typing can be recommended only for the identification of those strains which cannot be identified with the use of the phages of the International Basic Set. The results of the experiments with induced phages proliferating in a restriction-defective strain indicated that restriction and modification were mainly responsible for the specificity of lytic reactions.

Animals↗
PubMed1979

[Staphylococcus aureus infections in domestic fowls. 1. Ecology and epizootiology. (Review)].

The ecological and epizootiological aspects relating to Staphylococcus aureus in domestic fowl are expounded, on the basis of literature, with particular reference being made to five topics: occurrence of these conditionally pathogenic bacteria in domestic fowl, point of attack and routes of infection, conditions for possible occurrence of infections, reciprocal infection between man and animal, as well as aspects of therapy and prophylaxis.

Animals↗
PubMed1978

[The mutual transmission of Staphylococcus aureus between humans and cattle and the environmental adaptation of hemolysin and fibrinolysin formation].

In an ecological investigation in 20 dairy herds of cattle we compared the characteristics of strains isolated from nasal swabs of milkers, from the udder of cows and from cases of mastitis in cows. In 7 herds we found definite strains in the nasal flora of the milkers and in the udder-flora of the cows which only differ in the formation of hemolysin and of fibrinolysin. In the other checked characteristics strains from man and strains from cattle show identical patterns. In 5 herds these strains correspond to the host-specific variety hominis, in 2 herds to the hostspecific--variety bovis. These results refer to an environmental adaptation of the phenotypically detectable formation of hemolysins and fibrinolysin. From the ecological point of view an exchange of strains between man and cattle is likely. The origin of strains which can not be alloted to one ot the known host-specific varieties can be explained by an environmental adaptation. Besides the facts that strains of the host-specific variety bovis occur only very rarely in man and that strains of the host-specific variety hominis occur occasionally in cattle the clinical significance of the reported results has to be clarified by further investigations.

Adaptation, Biological↗