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PubMed1991

Insertional inactivation of the Staphylococcus aureus beta-toxin by bacteriophage phi 13 occurs by site- and orientation-specific integration of the phi 13 genome.

Lysogenization of Staphylococcus aureus by the serotype F converting bacteriophage phi 13 results in loss of beta-toxin expression. Sequence analysis of the S. aureus beta-toxin gene (hlb), the attachment site (attP)-containing region of phi 13 DNA and the chromosome/bacteriophage DNA junctions of a phi 13 lysogen, revealed that the molecular mechanism of loss of beta-toxin expression was due to insertion of the phi 13 genome into the 5' end of hlb. The insertion site (attB) within hlb contained a 14 base pair core sequence in common with attP and both ends of the integrated linear prophage genome of a phi 13 lysogen. These findings indicate that integration of the phi 13 genome into hlb is site- and orientation-specific.

Amino Acid Sequence↗
PubMed1995

Interaction of the chromosomal Tn 551 with two thermosensitive derivatives, pS1 and p delta D, of the plasmid pI9789 in Staphylococcus aureus.

The plasmid pI9789::Tn552 carries genes conferring resistance to penicillins and to cadmium, mercury and arsenate ions. The presence of Tn551 at one location in the chromosome of Staphylococcus aureus enhances the frequency of suppression of thermosensitivity of replication of the plasmids pS1 and p delta D which are derivatives of pI9789::Tn552. Bacteriophage propagated on the bacteria in which thermosensitivity of replication had been suppressed was used to transduce cadmium resistance to S. aureus PS80N. The cadmium-resistant transductants obtained carried plasmid pS1 or p delta D with a copy of Tn551 inserted into a specific site on pS1 but into several different sites on p delta D. The possible mechanisms of the suppression are discussed.

Base Sequence↗
PubMed1998

The two-component lysis system of Staphylococcus aureus bacteriophage Twort: a large TTG-start holin and an associated amidase endolysin.

The lysis genes of the virulent Staphylococcus aureus bacteriophage Twort were cloned and their nucleotide sequences determined. The endolysin gene plyTW encodes a 53.3-kDa protein, whose catalytic site is located in the amino-terminal domain. An enzymatically active fragment (N-terminal 271 amino acids) was overexpressed in Escherichia coli and partially purified. The enzyme rapidly cleaves staphylococcal peptidoglycan, and was shown to act as N-acetylmuramoyl-L-alanine amidase (EC 3.5.1.28). Significant sequence homology to the specific cell wall targeting domain of lysostaphin was observed in a 101-amino acid C-terminal overlap. However, we found that the large C-terminal portion (63%, 295 aa) of PlyTW is not required for staphylolytic activity. Located upstream of and overlapping plyTW by 35 bp in a different reading frame (+1), we identified holTW, which starts with a single TTG triplet. The gene specifies a 185-amino acid (20.5 kDa) holin protein, which features two potential hydrophobic, antiparallel transmembrane domains, and a highly charged, acidic C-terminus. HolTW is the largest class II holin described to date. It can substitute for the defective allele in phase lambda S' amber mutants, both in trans from an expression plasmid, and from within gt11::holTW. The proposed function is the formation of unspecific membrane lesions to promote access of the endolysin to the bacterial peptidoglycan.

Amino Acid Sequence↗
PubMed1999

A plasmid vector for isolation of strong promoters in Escherichia coli.

In order to isolate very strong promoters from bacteria and bacteriophage a plasmid named pProm was constructed. It possesses an origin (ORI) for replication in Gram-negative bacteria, an ORI for replication in Gram-positive bacteria, a promoterless ampicillin resistance gene with a multiple cloning site (MCS) in the position formerly occupied by the ampicillin promoter, a tetracycline resistance gene for selection in Gram-negative bacteria and a chloramphenicol resistance gene for selection in Gram-positive bacteria. Insertion in the MCS of DNA fragments of Staphylococcus aureus bacteriophages resulted in isolation of several clones very resistant to ampicillin. The DNA fragments inserted in these recombinant plasmids were sequenced and all of them contained putative promoter motifs. Direct measurement of the penicillinase activity indicated that one of the isolated promoters could be included within a group of the stronger known prokaryotic promoters. According to these results pProm is a powerful tool to perform studies on promoter strength and for industrial applications.

Base Sequence↗
PubMed2006

Lysis of staphylococcal mastitis pathogens by bacteriophage phi11 endolysin.

The Staphylococcus aureus bacteriophage phi11 endolysin has two peptidoglycan hydrolase domains (endopeptidase and amidase) and an SH3b cell wall-binding domain. In turbidity reduction assays, the purified protein can lyse untreated staphylococcal mastitis pathogens, Staphylococcus aureus and coagulase-negative staphylococci (Staphylococcus chronogenes, Staphylococcus epidermidis, Staphylococcus hyicus, Staphylococcus simulans, Staphylococcus warneri and Staphylococcus xylosus), making it a strong candidate protein antimicrobial. This lytic activity is maintained at the pH (6.7), and the "free" calcium concentration (3 mM) of milk. Truncated endolysin-derived proteins containing only the endopeptidase domain also lyse staphylococci in the absence of the SH3b-binding domain.

Animals↗
PubMed1983

Toxic shock syndrome and lysogeny in Staphylococcus aureus.

Lysogeny, or the presence of temperate bacteriophage, was demonstrated, by means of two Staphylococcus aureus indicator strains, in 11 of 12 strains of S. aureus isolated from patients with toxic shock syndrome. Only 1 of 18 strains of S. aureus that were not associated with toxic shock syndrome showed the presence of bacteriophage. A laboratory strain of S. aureus was lysogenized by bacteriophage from two of the toxic shock-associated strains. These results add support to the theory that lysogeny by one or more bacteriophage in certain strains of S. aureus may be responsible for the pathogenesis of toxic shock syndrome.

Bacterial Toxins↗
PubMed1980

Transduction of methicillin resistance in Staphylococcus aureus: recipient effectiveness and beta-lactamase production.

The effectiveness of Staphylococcus aureus strain 8325-4 as a recipient for the transduction of methicillin resistance requires the presence of a penicillinase plasmid but was found to be independent of the lysogenic state of the recipient. Effectiveness is conferred by the plasmid in either the autonomous or integrated states, although the transduction rate is higher in the former. Once established, the maintenance and expression of methicillin resistance were independent of continued carriage of the plasmid deoxyribonucleic acid. Analysis of penicillinase plasmid mutants indicated that beta-lactamase production was the plasmid function responsible for recipient effectiveness. Supportive evidence included the abrogation of recipient effectiveness by the beta-lactamase inhibitor clavulanic acid and the elimination of a plasmid requirement with recipient strains carrying a chromosomal beta-lactamase determinant. A possible role for beta-lactamase production in the transduction of methicillin resistance is discussed.

DNA, Bacterial↗
PubMed1986

Conjugative transfer of staphylococcal antibiotic resistance markers in the absence of detectable plasmid DNA.

Eleven Staphylococcus aureus clinical isolates were tested for transfer of resistance markers by transduction and filter mating. The resistance markers of six of the strains could be transferred only by transduction; however, the five remaining strains transferred their resistance both by transduction and filter mating. The resistance markers that were cotransferred in filter matings (transfer of resistance to penicillin and streptogramin A was accompanied, in each case, by the transfer of one or more markers, i.e., resistance to aminoglycosides, cadmium, or tetracycline, depending on the donor) were not cotransduced. The filter mating transfers were recA independent and were observed with both Staphylococcus aureus and Staphylococcus epidermidis recipients. Experiments to elucidate the mechanism of transfer by filter mating suggested that conjugation requiring cell-to-cell contact may have been involved. These transfers occurred in the absence of detectable plasmid DNA.

Anti-Bacterial Agents↗
PubMed2006

Using bacteriophages to reduce formation of catheter-associated biofilms by Staphylococcus epidermidis.

Use of indwelling catheters is often compromised as a result of biofilm formation. This study investigated if hydrogel-coated catheters pretreated with a coagulase-negative bacteriophage would reduce Staphylococcus epidermidis biofilm formation. Biofilms were developed on hydrogel-coated silicone catheters installed in a modified drip flow reactor. Catheter segments were pretreated with the lytic S. epidermidis bacteriophage 456 by exposing the catheter lumen to a 10-log-PFU/ml culture of the bacteriophage for 1 h at 37 degrees C prior to biofilm formation. The untreated mean biofilm cell count was 7.01+/-0.47 log CFU/cm2 of catheter. Bacteriophage treatment with and without supplemental divalent cations resulted in log-CFU/cm2 reductions of 4.47 (P<0.0001) and 2.34 (P=0.001), respectively. Divalent cation supplementation without bacteriophage treatment provided a 0.67-log-CFU/cm2 reduction (P=0.053). Treatment of hydrogel-coated silicone catheters with an S. epidermidis bacteriophage in an in vitro model system significantly reduced viable biofilm formation by S. epidermidis over a 24-h exposure period, suggesting the potential of bacteriophage for mitigating biofilm formation on indwelling catheters and reducing the incidence of catheter-related infections.

Biofilms↗
PubMed2006

Lytic activity of recombinant bacteriophage phi11 and phi12 endolysins on whole cells and biofilms of Staphylococcus aureus.

The recombinant phi11 endolysin hydrolyzed heat-killed staphylococci as well as staphylococcal biofilms. Cell wall targeting appeared to be a prerequisite for lysis of whole cells, and the combined action of the endopeptidase and amidase domains was necessary for maximum activity. In contrast, the phi12 endolysin was inactive and caused aggregation of the cells.

Amidohydrolases↗
PubMed1981

Vaginal isolates of Staphylococcus aureus associated with toxic shock syndrome.

Staphylococcus aureus has been isolated from vaginal fluids of women with toxic shock syndrome (TSS), a multisystem disease with onset usually during menses. A total of 15 vaginal isolates of S. aureus from TSS patients were compared with 18 vaginal isolates from women without TSS. Phenotypic traits which were significantly more frequent in the TSS group of strains than in the non-TSS group were arsenate resistance, proteolysis of hemoglobin, reduced hemolysis of sheep blood in agar medium, and lack of lethality of culture filtrates for chicken embryos and rabbits. In addition, isoelectric focusing of ethanol extracts of culture filtrates showed differences between the two groups in the occurrence of two proteins. All hemolytic and chicken embryo-lethal strains (3 TSS strains and 14 non-TSS strains) produced an extracellular protein with an isoelectric point of 8.6. In contrast, all TSS strains, but only one-half of non-TSS strains, released a protein with an isoelectric point of 7.0 and an apparent subunit molecular weight of 22,000.

Animals↗
PubMed1985

Acquired ability of Staphylococcus aureus to produce toxic shock-associated protein and resulting illness in a rabbit model.

Staphylococcus aureus from patients with toxic shock syndrome (TSS) produce TSS toxin 1. We transferred, by a bacteriophage, the ability to produce TSS toxin 1 from a TSS toxin 1-positive to a TSS toxin 1-negative strain of S. aureus. This recombinant strain produced TSS toxin 1 as confirmed by isoelectric focusing, immunodiffusion, radioimmunoassay, and autoradiography. The recombinant produced TSS-like illness in rabbits, and was significantly (P less than 0.001) more lethal than the recipient strain. Both strains produced fever and diarrhea, but, in addition, rabbits challenged with the recombinant also developed lowered blood pressure (P = 0.002), conjunctival hyperemia, erythroderma, and respiratory distress. Histopathological findings in rabbits challenged with the recombinant strain were remarkably similar to those described for humans with TSS, e.g., erythrophagocytosis, liver "triaditis," and vasodilatation. This study demonstrates that this protein may contribute to the pathogenesis of the TSS.

Animals↗
PubMed1990

Identification of a bacteriophage containing a silent staphylococcal variant enterotoxin gene (sezA+).

A variant enterotoxin gene, referred to as sezA+, has been identified. Staphylococcus aureus FRI1106, a staphylococcal enterotoxin type D producer (Sed+), contained HindIII fragments of 3.8 and 9.4 kilobase pairs (kbp) that hybridized in Southern blot analysis to a probe containing only staphylococcal enterotoxin type A structural gene sequences. Presumably, probe A-624 hybridized to the 9.4-kbp HindIII fragment because of the sequence homology between sea+ and sed+. This 9.4-kbp HindIII fragment, which was part of a staphylococcal plasmid, was isolated and ligated into an Escherichia coli plasmid vector; Sed+ E. coli recombinant clones were isolated. The 3.8-kbp HindIII fragment was shown to be part of a viable lysogenic bacteriophage, and it contained sezA+. This sezA(+)-containing fragment was cloned into E. coli, and its DNA sequence was determined. Examination of the nucleotide sequence revealed a 771-bp region that contained an open reading frame with 85 and 77% nucleotide and derived amino acid sequence identifies with sea+ and staphylococcal enterotoxin type A, respectively. This open reading frame has 83 to 50% nucleotide sequence identities with the other types of staphylococcal enterotoxin genes. sezA+ was shown to be transcribed into stable mRNA. However, the sezA+ mRNA was not translated into an enterotoxinlike protein because it lacks an appropriate translation initiation codon.

Amino Acid Sequence↗
PubMed1975

Bacteriophage-typable revertants from pleiotropic staphylococcal mutants.

Cell walls were physically purified from bacteriophage-typable revertants that had been isolated from modified cell wall pleiotropic strains derived from Staphylococcus aureus NCTC 8511. The quantitative amino acid, amino sugar, and phosphorus contents of these cell walls are reported. Among the revertants were some whose walls possessed elevated serine and one strain whose walls contained the novel amino sugar galactosamine. The similarities in bacteriophage typing patterns between the revertants and the original parental strain lead to the conclusion that the previously described pleiotropic strains are mutants of NCTC 8511.

Amino Acids↗
PubMed1978

Defect in biosynthesis of the linkage unit between peptidoglycan and teichoic acid in a bacteriophage-resistant mutant of Staphylococcus aureus.

The biosynthesis of the linkage region between peptidoglycan and the ribitol teichoic acid was investigated in the bacteriophage-resistant, teichoic acid-less mutant Staphylococcus aureus 52A5 (Chatterjee et al., J. Bacteriol. 100:846--853, 1969). Membrane preparations of this strain were found to be incapable of forming the first intermediate of the biosynthetic pathway, namely, the transfer of N-acetyl-D-glucosamine (GlcNAc) from UDP-GlcNAc to the acceptor molecule, which presumbably is undecaprenol phosphate (R. Bracha and L. Glaser, Biochem. Biophys. Res. Commun. 72:1091--1098, 1976). The addition of heat-inactivated membrane preparations of S. aureus 52A2 (which normally has ribitol teichoic acid) that had been preincubated with UDP-GlcNAc to membranes of strain 52A5 enabled the synthesis of teichoic acid. These data suggest that the mutational defect in the teichoic acid-less organism is in the synthesis of the first compound of the linkage unit, and this is apparently the reason for its absence in the cell walls.

Cell Wall↗
PubMed1983

Insertional inactivation of staphylococcal methicillin resistance by Tn551.

Transposon Tn551 was translocated into the chromosome of a methicillin-resistant (mec) strain of Staphylococcus aureus by heat inactivation of a thermo-sensitive plasmid carrying Tn551 and selection for erythromycin-resistant (Emr) survivors. Two independent chromosomal insertions of Tn551 were obtained which reduced the level of the methicillin resistance by a factor of 50 to 100, making the strains phenotypically methicillin sensitive (Mecs). Each of the Tn551 insertions was on the largest fragment produced by EcoRI digestion of the chromosomal DNA of these strains. The integration sites lie about 1 kilobase apart. These Mecs strains reverted to Mecr at frequencies of 2.4 X 10(-8) and 3.6 X 10(-5), respectively. The majority of Mecr revertants still were Emr; only a few lost the Emr phenotype concomitantly with reversion to the Mecr phenotype. Hybridization data with labeled Tn551 showed complex rearrangements and deletions in the region of the insertion. These two Tn551 insertions do not lie on the same linkage group, II, as the mec determinant. The phenotypic expression of methicillin resistance, therefore, is also dependent upon a chromosomal genetic marker not physically linked to the mec determinant.

DNA Transposable Elements↗
PubMed1989

Extent of the DNA sequence required in integration of staphylococcal bacteriophage L54a.

We characterized the minimum length of the DNA sequence of the attachment sites involved in the integrative recombination of staphylococcal bacteriophage L54a. A DNA fragment carrying the functional viral attachment site (attP) or the bacterial attachment site (attB) was sequentially trimmed, recloned, and tested for integrative recombination in vivo. The size of the functional attP site was at least 228 base pairs (bp) but no more than 235 bp. The left endpoint of the attP site was located to between positions -142 and -140, whereas the right endpoint was located to between positions +86 and +93 with respect to the center of the core sequence. The attB site was located to within a 27-bp sequence, from position -15 to +12, which included the 18-bp core sequence.

Base Sequence↗