Bactericidal Substance From Staphylococcus Aureus

Abstract

The majority of Staphylococcus aureus strains recovered in pure form from superficial skin lesions have been shown to belong to phage type 71 (1, 2). Certain unique features of this phage type have been described previously, among which are the common resistance to penicillin G (1, 2), inhibition of Corynebacterium diphtheriae on solid media (1, 3), and the production of opacity in horse serum agar, but not in egg yolk broth medium (3).In a previous communication from our laboratory (4), a bactericidal substance has been described in supernatant fluids from broth cultures of phage type 71 S. aureus. This substance was active against streptococci belonging to Groups A, C, and D, pneumococci, and corynebacteria. No inhibition of Group B streptococci or Gram-negative rods was noted, and inhibition of Group G streptococci and staphylococci was variable. The bactericidal substance has been shown to be a protein or a polypeptide. The present investigations further describe the biological properties of this bactericidal substance and indicate that it is distinct from other known staphylococcal products. Materials and MethodsMedla.--Trypdc soy broth (TSB) 1 (Difco) was used to cultivate all the staphylococcal strains. A dialysate medium of TSB was prepared as previously described (4)

Characterization and Extrachromosomal Control of Bacteriocin Production in Staphylococcus aureus

“…Most staphylococcins exert a much broader inhibitory spectrum than bacteriocins from gram-negative bacteria. Recent studies on the mode of action of two staphylococcins (6,19,20) showed that the membrane plays an important role.…”

Viridins, Bacteriocins of Alpha-Hemolytic Streptococci: Isolation, Characterization, and Partial Purification

“…Viridans streptococci, on the other hand, were usually resistant, and Another observation worthy of mention is the fact that within each group of indicator strains tested, a marked degree of variable susceptibilities was noted to the viridins, again suggesting heterogeneity among these bacteriocins at least in their spectra of activity. Previously described bacteriocins from grampositive bacteria, such as staphylococcins (4,6,8,9,11) and streptocins of group A (18,19) and B (17) streptococci, have had no effect on gramnegative bacteria. When the three viridins were tested against such organisms, surprisingly large numbers were found susceptible (Table 4).…”

“…In this study, gram-negative cocci were very commonly susceptible to all three viridins, and a variety of enteric gram-negative bacilli were also frequently inhibited. Although bacteriocins of gram-positive bacteria generally have a broader spectrum of activity than bacteriocins of gram-negative bacteria (13), no previously described bacteriocinogenic gram-positive bacterium has been shown to inhibit the growth of gram-negative bacteria (4,6,8,9,11,13,(17)(18)(19).…”

“…The concentration of a bacteriocin solution was estimated by twofold dilutions of the preparation in phosphate buffer and then spotting 0.05 ml of each dilution onto sections of a tryptic soy agar plate previously seeded with the indicator strain (4). The reciprocal of the highest dilution showing a clear zone of growth inhibition was considered the titer of the assayed preparation.…”

Natural history of impetigo

“…Phage group II S. aureus (3A, 3C, 55, and 71) have been repeatedly incriminated as the etiologic agents of bullous impetigo (5,8,17,18). Phage type 71 S. aureus possesses many unique features including production of a bacteriocin (19,20) which is markedly bactericidal to Group A beta hemolytic streptococci in vitro and in vivo (20,21). An implication of these experimental studies is that phage type 71 staphylococci may secondarily invade a preexisting streptococcal skin lesion and eradicate the streptococci from it.…”