Physical and Genetic Mapping of the Protein A Gene in the Chromosome of Staphylococcus aureus 8325-4

Abstract

The gene coding for protein A (spa) has been mapped close to nov on the genetic map of the chromosome of Staphylococcus aureus 8 325-4. A rapid mapping procedure has been developed which first allowed the region of the chromosome carrying the spa gene to be identified by blot hybridization of large DNA fragments which had been separated by pulsed-field gel electrophoresis. Restriction endonuclease SmaI fragment G was shown to carry the spa gene. An insertion mutation in spa was constructed by in vitro insertion of a fragment of DNA expressing resistance to kanamycin and neomycin. A spa : :KanrNeof mutation was isolated in S. aureus 8325-4 by allele replacement. This provided a selectable marker which allowed the spa gene to be mapped by transformation analysis.

Co-elimination of mec and spa genes in Staphylococcus aureus and the effect of agr and protein A production on bacterial adherence to cell monolayers

“…22 loss of resistance to mercury and cadmium and reduced resistance to t e t r a~y c l i n e .~~-~~ Production of protein A also can be co-eliminated with resistance to methicillin and re-introduced by transduction or transformation.27 Introduction of methicillin resistance can also modify levels of protein A expre~sion.~' The protein A gene (spa) maps near mec on the chromosome of strain 8325. 28 In this study, the production of protein A and homology for spa in MRSA and isogenic methicillinsensitive (Mc') variants was examined and the adherence of one pair of strains to cell monolayers was compared. Mutant strains for the spa and agr genes of S. aureus 8325-4 were compared for adherence to mesothelial cells.…”

Molecular Epidemiology of Methicillin-Resistant Staphylococcus aureus in Finland

“…SCCmec is always located in the same region in the S. aureus chromosome, between spa and purA (137,209). The sequence of the chromosomal region where SCCmec is integrated seems to be highly homologous among different strains.…”

Genome organisation of Staphylococcus aureus isolates from different populations

“…A single ISP8 SmaI fragment should hybridise to itself in a SmaI digest of ISP8, and should hybridise to one or more fragments obtained with the other endonuclease. This provides the overlap required for ordering of the fragments and comparison with the SmaI and CspI physical map of ISP8 [25,31]. One matter to be taken into account when comparing the hybridisation patterns is that ISP8 is a derivative (8325-4) of strain NCTC 8325 in which fragment SmaI-F has been lost (due to the loss of phages @ 11 and q5 13 carried on fragment SmaI-F), to be replaced by a fragment c. 73 kb smaller (Fig.…”

“…aureus 8325-4 (ISP8) [17] isolates were collected by nasal swabbing of a random selection of healthy individuals ( a random sample of university students), who had no history of hospitalisation, staphylococcal infection or disease in Canberra during 1990; these express resistance to not more than two antibiotics. Isolates were identified as S. aureus by growth and mannitol fermentation on Nutrient Agar (Oxoid) with NaCl 5%, and by a positive coagulase test and lysostaphin sensitivity.…”