Genetics of staphylococcal enterotoxin B in methicillin-resistant isolates of Staphylococcus aureus.
Biophysical and genetic analysis of staphylococcal enterotoxin B (SEB) synthesis in 16 methicillin-resistant (Mecr) Staphylococcus aureus isolates demonstrated that the toxin gene (entB) can occupy either a plasmid or chromosomal locus. Biophysical analysis of the plasmid deoxyribonucleic acid content of these strains by agarose gel electrophoresis revealed the presence of a 1.15-megadalton plasmid in six isolates that appears to contain the entB gene. Genetic manipulation of SEB synthesis by transduction and elimination procedures demonstrated that this plasmid is critical for enterotoxigenesis. Nevertheless, the majority of the Mecr SEB+ isolates (62.5%) analyzed in this investigation were found to lack the 1.15-megadalton plasmid. In at least two of these strains (COL and 57-dk), transduction and elimination procedures showed that entB was chromosomal. Genetic studies involving strains harboring either a plasmid or chromosomal entB gene demonstrated that toxin synthesis was coeliminated with mec. However, analysis of the entB and mec loci by transformation or transduction showed that the genes are not closely linked. On the other hand, transduction of entB, regardless of the donor, was observed when both mec and the Tcr plasmid were jointly cotransduced. This finding suggests that, during transduction, a transient association between entB, mec, and the Tcr plasmid may exist.
D002876:Chromosomes, Bacterial; D004768:Enterotoxins / Q000096:biosynthesis / Q000235:genetics*; D005796:Genes; D008712:Methicillin / Q000494:pharmacology; D010403:Penicillin Resistance; D010957:Plasmids; D013211:Staphylococcus aureus / Q000235:genetics*; D014161:Transduction, Genetic
D004768:Enterotoxins; D008712:Methicillin
Infect Immun. 1977 Apr;16(1):362-6
68931
Gene. 1978 Apr;3(2):145-59
95989
J Bacteriol. 1975 Sep;123(3):905-15
125746
Infect Immun. 1977 May;16(2):610-6
193794
J Bacteriol. 1978 Aug;135(2):460-5
249312
Appl Environ Microbiol. 1978 Mar;35(3):592-600
416755
Infect Immun. 1978 Apr;20(1):273-8
669796
Appl Environ Microbiol. 1978 Aug;36(2):389-91
697369
J Bacteriol. 1976 Sep;127(3):1529-37
821935
J Bacteriol. 1977 Jan;129(1):317-25
830641
J Med Microbiol. 1976 May;9(2):137-48
1047111
Bacteriol Rev. 1975 Mar;39(1):1-32
1091256
Appl Microbiol. 1974 Feb;27(2):317-23
4274664
Genetics. 1974 Apr;76(4):681-702
4275652
J Bacteriol. 1972 Nov;112(2):761-72
4343823
J Gen Microbiol. 1973 May;76(1):1-11
4489832
J Bacteriol. 1973 Nov;116(2):771-7
4490525
J Gen Microbiol. 1974 Sep;84(1):1-10
4497533
J Bacteriol. 1969 May;98(2):351-8
5192681
Ann N Y Acad Sci. 1971 Jun 11;182:279-94
5285292
J Gen Microbiol. 1963 Oct;33:121-36
14072829
J Bacteriol. 1970 Dec;104(3):1158-67
16559089