Methicillin-resistant Staphylococcus aureus in a London hospital.
Explore the source record for details and available documents.
SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Explore the source record for details and available documents.
Clonal dissemination of two different MRSA strains, both clumping factor negative, has been observed in Germany for more than a year. Both strains possess the mec-A determinant and each exhibits a characteristic genomic DNA fragment pattern. One strain has spread in the north, the other in the south-west of Germany. Intensive care units are mainly affected by MRSA-infections and probably play a special role in further intra- and inter-hospital spread.
Explore the source record for details and available documents.
1. In addition to poly(ribitol phosphate) the walls of a bacteriophage-resistant mutant of Staphylococcus aureus H contain glycerol phosphate residues that are not removed on digestion with trypsin or extraction with phenol. 2. The glycerol phosphate is present in a chain, containing three or four glycerol phosphate residues, which is covalently attached to the peptidoglycan through a phosphodiester linkage to muramic acid; this linkage is readily hydrolysed by dilute alkali. 3. The degradative studies described suggest that the poly(ribitol phosphate) chains of the wall teichoic acid may be attached to the wall by linkage to this glycerol phosphate oligomer.
Explore the source record for details and available documents.
The conversion of nontolerant Staphylococcus aureus to a tolerant organism is reported. It had been shown previously that a nontolerant strain produces tolerant progeny when it is incubated in media that contain a bacteria-free filtrate derived from cultures of each of the three tolerant stains of S. aureus. The tolerant progeny retain the characteristic tolerance upon serial subculture, and cell-free filtrates prepared from such subcultures are capable of converting nontolerant organisms to tolerant bacteria. A study of filtrates made from one of the tolerant strains revealed that all of the converting activity was sedimented by ultracentrifugation. DNase I and RNase A did not reduce the activity of the sediment, but Proteinase K completely diminished it. Equilibrium centrifugation of filtrates in cesium chloride showed that the conversion activity was maximal in the fraction with a density of approximately 1.445 +/- 0.015 g/ml. When a portion of this fraction was examined with the electron microscope, hexagonal bacteriophages (20 nm in diameter) were seen at this density. This observation seems to be evidence that a bacteriophage is involved in conversion of S. aureus from a nontolerant to a tolerant organism.
A total of 185 strains of methicillin resistant Staphylococcus aureus was investigated for sensitivity to five other antimicrobial agents. The vast majority of these strains were also resistant to gentamicin and fusidic acid. Rifampicin was the most active drug tested (MIC90, 0.007 mg/l), while two newer compounds teichomycin and ciprofloxacin showed equal and appreciable activity (MIC90, 0.5 mg/l).
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Antibiotic-resistant Staphylococcus aureus strains of animal origin were studied for transfer of resistance to human strains in vitro, with special reference to tylosin, an antibiotic which is used only in animals. Resistance to tylosin in animal and human strains was part of a constitutive resistance to all macrolide antibiotics. Resistance to tylosin could not be transferred from animal to human strains in vitro. Transfer of other resistances occurred between few strains and at low frequency. Resistance determinants from only seven animal cultures (out of 196 tested) could donate resistance to human strains in mixed cultures. The pattern of metal ion resistance was markedly different in animal and human strains: this supports the conclusion that spontaneous transfer between them is rare in nature.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Aminoglycoside-resistance determinants in staphylococci are borne on conjugative and non-conjugative plasmids. The conjugative plasmids were found in methicillin-resistant strains of Staphylococcus aureus isolated recently in Darwin and Sydney, Australia and in Houston, Texas, USA. These plasmids and the class-2 conjugative plasmid reported by Archer and Johnston (1983) had similar patterns of EcoR1 restriction-endonuclease fragments, encoded resistance to gentamicin, kanamycin and neomycin, transferred to a non-lysogenic recipient in conditions that promoted close cell-to-cell contact and mobilised a small, non-conjugative plasmid. A further plasmid, pWG14, encoding resistance to kanamycin, neomycin, streptomycin, erythromycin and lincomycin, also displayed conjugative properties but did not mobilise the small, non-conjugative plasmid. The transfer frequency of all conjugative plasmids was stimulated by the addition of polyethylene glycol, particularly at concentrations above 20%, to mixtures of donor and recipient broth cultures. Polyethylene glycol appeared to promote close cell-to-cell contact between donor and recipient cells. A representative of the most common aminoglycoside-resistance plasmids in Australian isolates of methicillin-resistant S. aureus was non-conjugative and transferred by a bacteriophage-mediated system to a lysogenic recipient. With the exception of plasmid pWG14, the conjugative plasmids were also transferred by a bacteriophage-mediated system. Furthermore, cultural conditions that favoured conjugative transfer of plasmids inhibited bacteriophage-mediated transfer and vice versa. The efficacy of the two transfer systems for analysing the plasmids of gentamicin-resistant, methicillin-resistant isolates of S. aureus has been compared.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.