Drug Resistance of Staphylococci II. Joint Elimination and Joint Transduction of the Determinants of Penicillinase Production and Resistance to Macrolide Antibiotics

Abstract

Drug resistance of staphylococci. II. Joint elimination and joint transduction of the determinants of penicillinase production and resistance to macrolide antibiotics. J. Bacteriol. 89:988-992. 1965.-Strains of Staphylococcus aureus, which show high resistance to macrolide antibiotics (erythromycin, oleandomycin, leucomycin, and spiramycin) and the capacity to produce penicillinase, have been isolated from clinical sources. The determinants of penicillinas] production (PCase+) and resistance to macrolide antibiotics (MACr) of these strains were irreversibly eliminated by treatment with acridine or with ultraviolet light. Among the 18 strains tested, PCase+ and MACr were eliminated from all strains except one, which lost only PCase+ but not MACr. The characters PCase+ and MACr were jointly transduced with the aid of phage lysates, obtained from the resistant donors by ultraviolet irradiation, into staphylococcal strains sensitive to PC and MAC. Segregation of PCase+ and MACr was rarely observed after transduction. From these results, it is suggested that the determinants of both PCase+ and MACr of staphylococci are located close together on a single genetic element, i.e., a plasmid (or episome), which exists extrachromosomally.

Transduction Analysis of the Genetic Determinants for Chloramphenicol Resistance in Staphylococci

“…According to the curing experiment and the genetic analysis, it was concluded that the locus for resistance to macrolide (Mac) antibiotics [13] and that for PC-resistance (penicillinase formation) [7,15,18] exist on a plasmid, indicating the existence of Table 5. Relative location of the loci controllingresistance to CM, TC and to SM either a (Mac.…”

Lability of Streptomycin Resistance in Staphylococcus aureus

“…Many papers have described the unstable resistance in staphylococci including the resistance to macrolide antibiotics [11,13,16], TC [1,8,10], PC [2,3,7,9,13,15], kanamycin [4] and chloramphenicol [4,9]. The first results of irreversible elimination of resistance to macrolide (Mac) antibiotics led us to the conclusion that the determinant responsible for Mac-resistance in staphylococci is located extrachromosomaly, probably being on a plasmid [11,16].…”

“…The first results of irreversible elimination of resistance to macrolide (Mac) antibiotics led us to the conclusion that the determinant responsible for Mac-resistance in staphylococci is located extrachromosomaly, probably being on a plasmid [11,16]. According to transduction analysis and genetic investigation, it was concluded that there were probably two plasmids; one carrying a PC-resistance determinant and another harboring both PC-and Mac-re-sistance determinants [7,[13][14][15][16]. Thereafter, many papers presented further proof that the genetic determinants for drugresistance in staphylococci are located on plasmid.…”

“…According to the results described in this article, it was concluded that the determinants responsible for SM-resistance were unstable and could be irreversibly lost from their host strains in some staphylococci. These facts have added an additional proof that the genetic determinant(s) for SM-resistance are unstable and are easily and irreversively lost during storage or by treatment with high temperatures in some strains of staphylococci, in addition to the determinants for Mac [11,13,16], TC [1,8,10], PC [2,3,7,13], kanamycin [4] and chloramphenicol [4,9] resistance. We conclude therefore that the unstable SM-determinant is located on a plasmid.…”

“…Many papers have described unstable drug-resistances in Staphylococcus aureus which could be irreversibly lost from the host strain when it was kept in stock culture, was grown at elevated temperatures, or by treatment with acridine dyes [1,11,13,15,16]. This paper deals with the elimination of streptomycin (SM) resistance in staphylococci isolated from clinical specimens.…”