Genetic mapping in phage group 2 Staphylococcus aureus

Abstract

Two regimens for transformation have been devised for the phage group 2 strains UT0002-19 and UT0017 of Staphylococcus aureus. Strain UT0002-19 produces exfoliative toxin, which is responsible for the clinical manifestations of the staphylococcal scalded skin syndrome, whereas strain UT0017 does not produce exfoliative toxin. A large pool of antibiotic-resistant and auxotrophic mutants from strains UT0002-19 and UT0017 were isolated by using (i) antibiotic gradient plates, (ii) trimethoprim selection, and (iii) nitrosoguanidine mutagenesis, which sometimes was coupled by enrichment with penicillin or methicillin. Transformation frequencies of genetic markers in mutant strains ranged from 106 to 108. Three genetic linkage groups were identified on the strain UT0017 chromosome. The first linkage group was thy-4-lys-5-trp-21-thr-4, the second was pyr-26-nov-9-his-3, and the third consisted of ilv-9 and pen-i, a genetic, determinant for ,8-lactamase synthesis. Two linkage groups were detected on the strain UT0002-19 chromosome. The first was defined as thy-l-lys-5-trp-3-thr-4-ala-8, whereas the second consisted of nov-9 and his-3 markers. A chromosomal locus that controlled synthesis of exfoliative toxin could not be mapped.

Plasmids in Epidermolytic Strains of Staphylococcus aureus

“…to known chromosomal markers. Such experiments have been attempted without success by Martin et al (1980). Serotype ii ET was invariably plasmid-controlled because it was readily lost from all strains tested when the cells were grown in conditions which promoted the loss of plasmids.…”

Genetic transformation in Staphylococcus aureus: demonstration of a competence-conferring factor of bacteriophage origin in bacteriophage 80 alpha lysates

“…Competence-conferring activity of isolated phage particles. Although UV inactivation of infectious phage particles in phage lysates did not appear to affect the competence-conferring activity of the lysates (29), more than one phage particle per cell appeared to be required to obtain maximum levels of competence (14,29). However, early in the course of this study, it was observed that the competence-conferring activities of various preparations of bacteriophage 80a varied, despite the fact that these lysates contained equivalent numbers of plaquefonning units.…”

Mutagenesis of extrachromosomal genetic determinants for exfoliative toxin B and bacteriocin R1 synthesis in Staphylococcus aureus after plasmid transfer by protoplast fusion

“…Fortunately, this is no longer the case. In addition to transduction, DNAmediated transformation (3,4,11), a conjugallike mechanism (5), and PEG-induced protoplast fusion are also now available as tools to investigate staphylococcal genetics.…”

“…This mixture was allowed to incubate at room temperature for at least 1 min. To isolate chromosomal recombinants, 0.02 ml of 1 M CaC12 was added to the suspension at (4) strain that was made erythromycin resistant. SM0005 rif Obtained after protoplast fusion of This paper strains UT0100 (rif) and UT0002…”