Transduction of Penicillinase Production and Methicillin Resistance-Enterotoxin B Production in Strains of Staphylococcus aureus

Abstract

It is suggested that wild strain ~~4 9 1 6 of Staphylococcus aureus harbours at least two plasmids. One of them is responsible for penicillinase production and resistance to metallic ions and the other for methicillin and cephalothin resistance together with enterotoxin B production. These properties were eliminated en bloc with acridines as well as separately at different rates. Transductions were performed to restore the eliminated characters with typing phages 29 and 88. Recombination of the markers for penicillinase production and methicillin resistance on the transduced fragment seems advantageous for selection of methicillin resistance.

Clonal study of enterotoxin-B producing strains ofStaphylococcus aureus

“…Responsible mainly for food poisoning, it has also been associated with toxic shock [4][5][6]. The properties of SEB-producing strains (SEB+) are well documented; Asheshov and co-workers [7] demonstrated that the strains in the 94/96 phage complex were very often SEB+; Melconian and colleagues [8] observed that these strains were lysed mainly by phages of groups II and V; and Dornbusch and Hallander [9] have demonstrated a relationship between oxacillin resistance and toxin production. Recently, Lee and colleagues [10] have shown that TS-associated strains produced either TSST-1, enterotoxin B or, exceptionally, both; they have also shown that SEB+ strains belonged to the same zymotype, suggesting a clonal origin.…”

Methicillin-resistant staphylococci

“…Initial confusion about whether the genetic determinant, mec, of methicillin resistance resided on plasmid or chromosomal deoxyribonucleic acid (DNA) has been resolved. Evidence for a plasmid location was indirect and based on characteristics of elimination of mec from resistant strains (51,52,73,98). However, some conditions associated with the elimination, transduction, and transformation of mec suggested that the determinant was chromosomal (38,90,91,151).…”

“…Interestingly, this 3.5-kb probe also hybridized with penicillinase plasmid fragments from susceptible and resistant strains and with two 500-base-pair fragments flanking the determinant for mercury resistance in the penicillinase plasmid pI524. These 500-base-pair fragments may be insertion sequences that at times permit mec to function as a transposable element (51,105,141,142).…”

Compatibility Tests between Genetic Linkage Groups in a Strain of Staphylococcus aureus

“…In this investigation, attempts are made to describe more fully some possible plasmids in a strain of Staphylococcus aureus (Dornbusch, Hallander & Lofquist, 1969 ;Dornbusch & Hallander, 1973). The methods used are compatibility tests achieved by transducing defined plasmids into the strain and examination of the penicillinase activity of the strain after addition of antiserum.…”