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Biomedical subjects

W Witte

Publications and source records attributed to W Witte.

At least 109 records · Page 6Linked to original sources
PubMed1990

Typing of multiple isolates of coagulase-negative staphylococci from blood cultures and cerebrospinal fluid in neonates and children: an approach to discriminate contaminants.

From eight neonates and children suspicious for suffering from septicemia and/or meningitis, coagulase negative staphylococci (CNS) were isolated from multiple blood cultures and from cerebrospinal fluids originating from different punctures. S. epidermidis was the predominant species. By a further typing using plasmid-profiles and exoprotein patterns besides the resistance phenotype, contaminants could be discriminated from the isolates as the probable etiologic agent exhibiting unique reaction patterns. CNS isolated from cases of septicemia together with other bacterial pathogens or from cases of presumed but not confirmed septicemia revealed as different.

Adolescent↗
PubMed1990

A single clone of Staphylococcus aureus causes the majority of cases of toxic shock syndrome.

Genetic relationships among 315 isolates of the bacterium Staphylococcus aureus expressing toxic shock syndrome toxin-1 (TSST-1) recovered primarily from humans with toxic shock syndrome (TSS) in five countries on two continents were determined by analyzing electrophoretically demonstrable allelic variation at 20 chromosomal enzyme loci. Forty-nine distinctive electrophoretic types (ETs), representing multilocus enzyme genotypes, were identified. Cluster analysis of the ETs revealed two major phylogenetic divisions separated at a genetic distance of 0.35 and seven branches diverging from one another at distances greater than or equal to 0.20. A single clone (ET 41) accounted for 88% of cases of TSS with a female urogenital focus and 53% of TSS cases involving nonurogenital (predominantly wound) infections. With few exceptions, strains representing different phylogenetic lines had characteristic TSST-1 gene (tst) restriction fragment length polymorphism patterns obtained by digestion of genomic DNA with Cla I. Strains recovered from ovine and bovine hosts with mastitis were genotypically distinct from the major human TSS clone. The expression of TSST-1 in cell lineages representing the total breadth of multilocus genotypic diversity in the species S. aureus as a whole is interpreted as evidence that the TSST-1 gene is evolutionarily old. The recovery of a single clone from the majority of individuals afflicted with TSS having a urogenital focus and from the genital tract of a large proportion of asymptomatic female carriers strongly suggests that this clone is especially well adapted for colonization of these anatomic sites.

Animals↗
PubMed1989

Activity of clavulanate-potentiated penicillins against methicillin-resistant Staphylococcus aureus.

It has been suggested that combinations of penicillins with clavulanate may be useful in treatment of infections by methicillin-resistant strains of Staphylococcus aureus (MRSA). To determine the potentiating effect of clavulanate on the antibacterial activity of penicillins, we studied MRSA in vitro by an agar-dilution method. A total of 124 clinical isolates of MRSA were tested for sensitivity to benzylpenicillin, amoxycillin, and ticarcillin alone and in combination with 1.25, 2.5, 5.0 and 10.0 mg/l of clavulanate. Most of the strains were not typable by the international reference set of bacteriophages of human staphylococci but showed typical properties of nosocomial strains. A reduction in the MIC90 of benzylpenicillin and amoxycillin to 25 mg/l was seen in the presence of 2.5 mg/l of clavulanate. The effect was less pronounced with ticarcillin. In spite of some increase in the susceptibility of MRSA to benzylpenicillin and amoxycillin produced by clavulanate, these combinations seem to be inappropriate in infections due to MRSA.

Clavulanic Acids↗
PubMed1989

[Nosocomial infections caused by multi-resistant Serratia marcescens at a university clinic--clinical aspects and drug resistance].

Serratia marcescens (S.m.) has become increasingly important as a nosocomial pathogen and displayed an increasing resistance to antimicrobial agents in the past decade. We recently studied in 1985 and 1986 an epidemic caused by multi resistant S.m. strains that involved 27 infants and 1 adult patient. 14 neonates (in most cases very low birth weight infants) in a neonatal intensive care unit developed a S.m.-septicemia and/or meningitis, 11 of them died. In a ward for young infants with congenital heart diseases 13 patients suffered a S.m. infection and one patient died in the adult intensive care unit in consequence of a S.m. septicemia.

Anti-Bacterial Agents↗
PubMed1988

Complex typing of methicillin-resistant Staphylococcus aureus (MRSA).

To discriminate between methicillin-resistant Staphylococcus aureus from 5 nosocomial outbreaks and from sporadic nosocomial infections, the efficacy of a complex typing scheme by phage typing, biochemical typing, resistance phenotype, plasmid profiles, plasmid patterns and attribution of resistance determinants to the chromosome was studied. In addition to the International Basic Set and experimental phages 88-93, 10 experimental phages from the Public Health Laboratory Service, Colindale, London, were used for phage-typing. The 10 experimental phages from PHLS in particular, in combination with plasmid profiles and plasmid patterns, were of special discriminative value.

Bacterial Typing Techniques↗
PubMed1988

[Coagulase-negative Staphylococcus species in mixed fodder and on grain].

For valuation of microbially-altered combined fodder from the veterinary point of view beside the total number of germs also the diagnosis of the species of veterinary relevant indicator germs is of importance. Coagulase-negative staphylococci are the main and indicator flora in spoiling of combined fodder. According to the biochemical and physiological characterization the majority of the coagulase-negative staphylococci occurring in connection with spoiling of combined fodder belongs to the species S. xylosus. Beside the species also other coagulase-negative species as S. sciuri, S. cohnii, S, warneri and S. saprophyticus have been demonstrated. These bacterial species were also found in the single components of combined fodder as ripe grain, green unripe cereal plants, in soil samples and in the dust inside the mills for combined fodder production.

Animal Feed↗
PubMed1987

Staphylococcus aureus strains of the 94/96 complex isolated in the German Democratic Republic: incidence and discrimination of strain clones.

The incidence of S. aureus with a phage pattern of 94/96 rose from 9% in 1979 to 18% in 1985. The frequency of occurrence not only increased among isolates from inpatients and outpatients but also among those from healthy carriers. All of the 504 investigated strains of different origin exhibited a uniform pattern of biochemical characteristics. In each of 40 investigated strains, a plasmid with a molecular mass of 16 Md was found. Elimination experiments indicated that these plasmids determined resistance to penicillin and/or cadmium. Resistance to chloramphenicol was found to be determined by plasmids of 2.0 Md, resistance to oxytetracycline by plasmids of 2.7 Md. Clones could be discriminated by means of 7 experimental phages. The application of these phages for typing strains from infections in hospitals is demonstrated.

Bacteriophage Typing↗
PubMed1987

Multiply- and methicillin-resistant Staphylococcus aureus strains isolated in the German Democratic Republic in 1985 and 1986.

Multiply- and methicillin-resistant Staphylococcus aureus (MRSA) strains have been isolated from five small outbreaks of nosocomial infection in five different hospitals. The MRSA were typed by phage patterns, biochemical traits, resistance phenotypes and plasmid patterns. Three different groups of strains can be distinguished. The MRSA from three outbreaks in one country share identical characters. Phage typing by the use of the International Basic Set for Phage Typing staphylococci as well as experimental phages does not completely discriminate between the strains. Attribution of several resistance determinants to plasmids in two of the described strain groups proved valuable for strain differentiation. These multiply-resistant strains are sensitive to vancomycin and to rifampicin.

Cross Infection↗
PubMed1986

Spread of plasmid-mediated nourseothricin resistance due to antibiotic use in animal husbandry.

After using of the streptothricin antibiotic nourseothricin in animal husbandry for growth promotion, plasmid-borne resistance to streptothricin could be observed in E. coli from nourseothricin fed pigs, from employees in pig farms and from their family members. Moreover, streptothricin resistance plasmids also occurred in E. coli of man without any contact to pig farms (gut flora and even urinary tract infections). However, these individuals live in villages and towns of the territory where nourseothricin was applied to pigs. Similar streptothricin resistance plasmids belonging to different incompatibility groups were found in both E. coli from pigs and E. coli from human beings. As no coselection of resistance to drugs indispensable for therapeutic use in man was observed, the application of nourseothricin in animal husbandry has not clinical implication for human medicine yet. Nevertheless, this problem remains under further investigation.

Animal Husbandry↗
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↗