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PubMed1987

Cell surface hydrophobicity and charge of Staphylococcus aureus and coagulase-negative staphylococci from bovine mastitis.

The effects of seven growth media on cell surface hydrophobicity of a collection of Staphylococcus aureus and coagulase-negative staphylococci isolated from bovine mastitis were compared in the salt-aggregation test. Thirty-three per cent of Staph. aureus strains showed extremely high cell surface hydrophobicity (auto-aggregated) and 28% were moderately hydrophobic while 26% were hydrophilic after growth on horse blood agar at 37 degrees C for 18 h. There were great variations in the proportion and degree of the hydrophobicity depending on the medium used. Cultivations on/in capsule-inducing media caused a shift from a high to a low degree of hydrophobicity, although a microscopically detectable capsule or slime layer was seen in only one strain. This strain and encapsulated reference strains had a hydrophilic cell surface and migrated faster in free zone electrophoresis than cells of unencapsulated strains. Cells of strains grown on staphylococcus medium 110 agar migrated faster than those grown on horse blood agar regardless of their capsule production. Coagulase-negative staphylococci showed uniformly hydrophilic cell surface after cultivation on horse blood agar, but not when grown in tryptic soy broth or proteose peptone broth. It was concluded that most of the Staph. aureus strains from bovine mastitis under a variety of growth conditions in stationary phase culture constantly expressed hydrophobic cell surface.

Animals↗

PubMed2004

PCR detection of staphylococcal enterotoxin genes in Staphylococcus spp. strains isolated from meat and dairy products. Evidence for new variants of seG and seI in S. aureus AB-8802.

AIMS: Evaluation of the occurrence of most known staphylococcal enterotoxin (SE) genes, egc (enterotoxin gene cluster) and TSST1 (toxic shock syndrome toxin 1) gene in both coagulase-positive (CPS) and coagulase-negative (CNS) staphylococcal strains isolated from meat and dairy products. METHODS AND RESULTS: Specificity and reliability of the PCR detection methods used were ascertained by using nine reference strains of Staphylococcus (S. aureus) harbouring SE genes (seA to seE; seG, seH, seI, seM, seJ, seN and seO) and egc (containing the following sequence of genes: seO, seM, seI, phient1, phient2, seN and seG). Of 109 wild Staphylococcus spp. strains analysed, only 11 S. aureus strains were SE and/or TSST1 PCR-positive. The last 11 strains also appeared to harbour the egc. Restriction endonuclease analysis of part of the egc of both reference and wild strains showed that different variants of the egc exist. Moreover, nucleotide sequences of seG and seI indicate that the egc of the strain AB-8802 is characterized by the presence of variants of these enterotoxins (seGv and seIv). CONCLUSIONS: The occurrence of SE genes in CNS and other non-S. aureus species isolated from Napoli-type salami, raw water buffalo milk and natural whey cultures used for mozzarella cheese manufacturing is very rare. SIGNIFICANCE AND IMPACT OF THE STUDY: During this study it was shown that at least five different egc may exist in S. aureus. A thorough study of egc polymorphism should provide further insight into the phylogenetics of the egc.

Bacterial Toxins↗

PubMed1998

Purification and properties of a bacteriocin of Staphylococcus epidermidis isolated from dental plaque.

An extracellular bacteriocin of Staphylococcus epidermidis isolated from dental plaque was purified and characterized. Its molecular mass was 3500 Da and pI was 10.5. This bacteriocin inhibited the growth of Staphylococcus aureus, Streptococcus salivarius, and Streptococcus mitis, but Streptococcus mutans, Streptococcus sanguis and other oral indigenous bacterial species examined were not inhibited. The mode of inhibition was found to be bacteriostatic.

Bacterial Proteins↗

PubMed1992

Lytic activities, protein profiles and morphologic characteristics of new bacteriophages isolated from canine and human Staphylococcus aureus strains.

The lytic activity, protein profile and morphology of five newly isolated phages from canine Staphylococcus aureus strains and one from a human S. aureus strain were compared with those of selected phages in the international phage sets (IPS). Five canine phages lysed 57 (76.0%) of 75 canine isolates of Staphylococcus aureus from Nigeria at routine test dilution (RTD) while 34 (IPS) phages typed only 31 (41.3%) strains at RTD or/and 100-RTD. The new human phage lysed 11 (14.7%) of 75 strains isolated from human diarrhoea. The new phages were readily propagated, specific in activity and stable during storage at 4 degrees C. Prominent proteins detected by SDS-PAGE indicated similarities between some of the phages but one canine phage was distinctly different, as was its morphology which was an isometric head with a short tail compared to oval heads and long tails which characterized others. IPS phages in the same serologic group had similar protein profiles but no correlation was observed with lytic groups. The use of protein profile and electron micrographs allowed classification of the phages into serogroups. It is concluded that the newly isolated canine phages could be very useful in typing Nigerian canine strains of S. aureus.

Animals↗

PubMed1961

A comparative study of staphylococcus haemolysins and Colisan.

Staphylococcus beta-haemolysin exhibits the same broad spectrum of antagonistic activity against smooth muscle stimulants as described recently for Colisan. The antispasmodic effect develops slowly and can be removed only by repeated washing. The pattern of haemolytic activities of Colisan is characteristically different from that of beta-haemolysin, but resembles closely alpha-toxin. Both staphylococcus toxins can destroy paramecium and entamoeba, but the ratio of the titres at which they kill paramecium and entamoeba respectively (P:A value) is different. The P:A value of beta-haemolysin is similar to that of Colisan.

Antitoxins↗

PubMed1993

Serotype F double- and triple-converting phage insertionally inactivate the Staphylococcus aureus beta-toxin determinant by a common molecular mechanism.

The precise molecular mechanism of Staphylococcus aureus beta-toxin inactivation by the serotype F triple-converting phage phi 42, phi A1 and phi A3 was investigated. Sequence analysis of the phi 42 (attP) and Staphylococcus aureus (attB) attachment sites and the left (attL) and right (attR) chromosomal/bacteriophage DNA junctions of individual lysogens, each harbouring a triple-converting phage, revealed the presence of a common 14-bp core sequence in all four sites. These findings indicate that the genomes of the triple-converting phage integrate into the 5'-end of the beta-toxin gene (hlb) by a site- and orientation-specific mechanism identical to that previously described for the serotype F double-converting phage phi 13.

Attachment Sites, Microbiological↗

PubMed1998

Cloning and characterization of an accessory gene regulator (agr)-like locus from Staphylococcus epidermidis.

The presence of sequences related to the agr of Staphylococcus aureus was demonstrated in Staphylococcus epidermidis by agr-specific PCR, and Southern blot. The agr-like locus of S. epidermidis A086 was cloned and sequenced. An overall homology of 68% was found between the agr locus from S. epidermidis and S. aureus. The agr locus from S. epidermidis was organized similar to those from S. aureus and S. lugdunensis. The putative RNAII molecule contains four open reading frames, agr A, B, C and D. AgrA was a response regulator. AgrB showed homology with transducer and translocase molecules. AgrC is expected to act as a histidine protein kinase in which a leucine zipper is present. AgrD is presumably processed into an autoinducer peptide. The putative RNAIII molecule contained an open reading frame encoding a putative 26 amino acid (aa) polypeptide, which differed in 3 aa from the RNAIII encoded delta-toxin of S. aureus. Kinetic studies showed that the production of this RNAIII was elevated during the post-exponential phase. delta-Toxin activity was demonstrated for 21 of 23 tested S. epidermidis strains. Kinetic studies of the production of delta-toxin showed that the toxin was produced during the post-exponential phase. Sequencing of S. epidermidis A097, which showed a delayed agr-response, revealed a truncated AgrC lacking the histidine kinase domain. These data indicate that an agr-like locus is active in S. epidermidis during the post-exponential phase.

Amino Acid Sequence↗

PubMed1999

Transposition of IS1181 in the genomes of Staphylococcus and Listeria.

The recombinant plasmid pIP1713 was constructed to analyse the transpositional activity of the insertion sequence IS1181 in Staphylococcus aureus RN4220, Staphylococcus carnosus TM300 and Listeria monocytogenes EGD. This 11.3-kb plasmid contains two genetically different elements: (i) a pE194ts-derived replicon, the ermC gene of which confers resistance to erythromycin in Gram-positive bacteria of several species, and (ii) a copy of IS1181, cloned from S. aureus BM3121, in which the tetracycline resistance gene, tet(T), has been inserted between the transposase-encoded gene and the downstream inverted repeat. When introduced by electroporation into the three bacterial hosts, pIP1713 delivered IS1181 omega tet(T) to various chromosomal sites. Cointegrate structures between pIP1713 and the host chromosome were occasionally detected. Transposition was associated with 8-bp repeats at the insertion sites. IS1181 omega tet(T) could be used for random mutagenesis in Gram-positive bacteria.

Base Sequence↗

PubMed1983

Comparison of four methods for differentiation of Staphylococcus aureus from other Micrococcaceae in the routine laboratory.

Four methods for the identification of Staphylococcus aureus (tube coagulase test, thermostable nuclease test, indirect agglutination of fibrinogen coated erythrocytes and a commercial latex kit: SeroSTAT Staphylococcus Test) have been compared. Clinical isolates (698) and 40 reference strains of Micrococcaceae were included in the study together with control organisms. The coagulase test gave no false positive results but 39/406 clinical isolates of S. aureus were negative at 2h and one half were only weakly positive. At 18 h, all but 2 of 406 isolates gave a positive reaction. The thermostable nuclease test was very specific; no clinical isolates of S. aureus gave negative results and no "coagulase-negative" clinical isolates gave a definite positive reaction. The indirect haemagglutination method was sometimes difficult to interpret and frequently gave negative or doubtful results for S. aureus. The SeroSTAT test was easy to use and interpret and was specific; the method is suitable for routine laboratory use, particularly when a rapid result is desirable.

Bacteriological Techniques↗

PubMed1985

Population analysis of susceptibility to cefotaxime and desacetyl-cefotaxime in Staphylococcus and Enterobacteriaceae.

Population analyses of susceptibility to cefotaxime (CTX) and desacetyl-cefotaxime (DCTX) of strains of Staphylococcus and some genera of Enterobacteriaceae were carried out. DCTX, which is the main metabolite of CTX, has antimicrobial activity. The penicillinase-producing strains of S. aureus and S. epidermidis were homogeneous as regards susceptibility to both agents. CTX was about 4-8 times more active than DCTX. The methicillin-resistant strains contained a sub-population of resistant bacteria with both CTX and DCTX. The frequency of resistant bacteria was 10(-6) - 10(-5). The E. coli strain was homogeneous to both agents. The strains of Enterobacter cloacae and Citrobacter freundii had a sub-population of resistant bacteria with both agents. The frequency of resistant bacteria was 10(-7) - 10(-4.5). In Klebsiella pneumoniae no resistant sub-population was found. CTX was about four times more active than DCTX with the strains of the Enterobacteriaceae. DCTX had no advantage over CTX as regards homogeneity of susceptibility of the populations examined. CTX seems applicable for treatment of infections with E. coli, Klebsiella pneumoniae, and penicillinase-producing, methicillin-susceptible Staphylococcus, but should not be used alone in treatments of infections with Enterobacter cloacae or Citrobacter freundii.

Cefotaxime↗

PubMed2006

A subset of Staphylococcus aureus strains harboring staphylococcal cassette chromosome mec (SCCmec) type IV is deficient in CcrAB-mediated SCCmec excision.

The gene encoding resistance to beta-lactam antibiotics in the staphylococci is found on the chromosome in a genomic island designated staphylococcal cassette chromosome mec, or SCCmec. In addition to the resistance gene mecA, SCCmec also contains site-specific recombinase genes that are capable of catalyzing the chromosomal excision and reintegration of SCCmec. SCCmec is found in five major isotypes partially defined by the recombinase genes present, either ccrAB or ccrC. Of these, SCCmec type IV is presumed to be mobile in the environment, and this mobility may be partially responsible for the rise in community-associated methicillin-resistant staphylococcal infections. In this study, we investigate the presumptive first step in type IV SCCmec mobility: chromosomal excision of the element. CcrAB from a panel of six Staphylococcus aureus and four Staphylococcus epidermidis strains were able to catalyze chromosomal excision of SCCmec types I and II, indicating that these proteins maintain recombinase activity despite varying by up to 3.7% at the amino acid level. Excision of type IV SCCmec was not universally seen, as a subset of S. aureus strains with type IV SCCmec did not excise their element. These strains are all highly related and represent a lineage of successful community-associated pathogens. In addition, the inability to excise SCCmec in these strains is associated with the insertion of a presumptive mobile element containing the gene for staphylococcal enterotoxin H (seh) immediately downstream of SCCmec on the chromosome. Acquisition of this mobile element, containing a known virulence gene, appears to have stabilized the chromosomal integration of the methicillin resistance gene in these strains.

Anti-Bacterial Agents↗

PubMed1993

Detection and characterization of mupirocin resistance in Staphylococcus aureus.

Fourteen mupirocin-resistant Staphylococcus aureus strains were isolated over 18 months; 12 exhibited low-level resistance, while two showed high-level resistance. Highly mupirocin-resistant strains contained a large plasmid which transferred mupirocin resistance to other S. aureus strains and to Staphylococcus epidermidis. This plasmid and pAM899-1, a self-transferable gentamicin resistance plasmid, have molecular and biologic similarities.

Conjugation, Genetic↗

PubMed2002

Combinations of lysostaphin with beta-lactams are synergistic against oxacillin-resistant Staphylococcus epidermidis.

Oxacillin-resistant Staphylococcus aureus is rapidly killed by the endopeptidase lysostaphin, and the addition of beta-lactam antibiotics provides synergistic killing. We investigated the possibility that beta-lactams given in combination with lysostaphin would improve the activity of lysostaphin against oxacillin-resistant Staphylococcus epidermidis (ORSE), which is normally less susceptible to lysostaphin. Checkerboard synergy testing was performed for lysostaphin given in combination with oxacillin against 10 ORSE isolates for which the lysostaphin MICs were > o r= 8 microg/ml. The fractional inhibitory concentration index ranged from 0.0234 to 0.2656, indicating synergy, which was confirmed in growth curve experiments. In the rabbit model of experimental aortic valve endocarditis using an ORSE strain, the combination of lysostaphin and nafcillin was as effective as vancomycin alone and significantly better than lysostaphin or nafcillin alone. We conclude that beta-lactam antibiotics given in combination with lysostaphin are synergistic against many strains of ORSE.

Animals↗

PubMed2004

Reduced triclosan susceptibility in methicillin-resistant Staphylococcus epidermidis.

Triclosan MIC determination showed that recent Staphylococcus aureus clinical isolates (n = 100) were highly susceptible to triclosan, with a 50% minimal inhibitory concentration (MIC(50)) of 0.12 microg/ml and a MIC(90) of 0.25 microg/ml. Staphylococcus epidermidis isolates (n = 96) were less susceptible, with a MIC(50) of 0.12 microg/ml and a MIC(90) of 8 microg/ml. Decreased susceptibility to triclosan was more prevalent among methicillin-resistant S. epidermidis than among methicillin-sensitive S. epidermidis isolates.

Anti-Infective Agents, Local↗

PubMed2001

Analogs of Eap protein are conserved and prevalent in clinical Staphylococcus aureus isolates.

Map and Eap are secreted Staphylococcus aureus proteins that interact with various extracellular matrix molecules. PCR analysis using map primers yielded positive reactions in 97.9% of S. aureus isolates but not in Staphylococcus epidermidis isolates. Cloning and sequencing of the conferring genes revealed a high degree of overall homology combined with size variability of the gene product due to various repeat numbers and early translation termination in a poly(A) region. Thus, Map and Eap may provide a potential novel tool for S. aureus identification and typing.

Amino Acid Sequence↗

PubMed2005

Extracellular carbohydrate-containing polymers of a model biofilm-producing strain, Staphylococcus epidermidis RP62A.

Staphylococcus aureus and coagulase-negative staphylococci, primarily Staphylococcus epidermidis, are recognized as a major cause of nosocomial infections associated with the use of implanted medical devices. It has been established that clinical isolates often produce a biofilm, which is involved in adherence to biomaterials and provides enhanced resistance of bacteria against host defenses and antibiotic treatments. It has been thought that the staphylococcal biofilm contains two polysaccharides, one responsible for primary cell adherence to biomaterials (polysaccharide/adhesin [PS/A]) and an antigen that mediates bacterial aggregation (polysaccharide intercellular adhesin [PIA]). In the present paper we present an improved procedure for preparation of PIA that conserves its labile substituents and avoids contamination with by-products. Based on structural analysis of the polysaccharide antigens and a thorough overview of the previously published data, we concluded that PIA from S. epidermidis is structurally identical to the recently described poly-beta-(1-->6)-N-acetylglucosamine from PS/A-overproducing strain S. aureus MN8m. We also show that another carbohydrate-containing polymer, extracellular teichoic acid (EC TA), is an essential component of S. epidermidis RP62A biofilms. We demonstrate that the relative amounts of extracellular PIA and EC TA produced depend on the growth conditions. Moderate shaking or static culture in tryptic soy broth favors PIA production, while more EC TA is produced in brain heart infusion medium.

Acetylglucosamine↗

PubMed2006

First complete genome sequence of two Staphylococcus epidermidis bacteriophages.

Staphylococcus epidermidis is an important opportunistic pathogen causing nosocomial infections and is often associated with infections in patients with implanted prosthetic devices. A number of virulence determinants have been identified in S. epidermidis, which are typically acquired through horizontal gene transfer. Due to the high recombination potential, bacteriophages play an important role in these transfer events. Knowledge of phage genome sequences provides insights into phage-host biology and evolution. We present the complete genome sequence and a molecular characterization of two S. epidermidis phages, phiPH15 (PH15) and phiCNPH82 (CNPH82). Both phages belonged to the Siphoviridae family and produced stable lysogens. The PH15 and CNPH82 genomes displayed high sequence homology; however, our analyses also revealed important functional differences. The PH15 genome contained two introns, and in vivo splicing of phage mRNAs was demonstrated for both introns. Secondary structures for both introns were also predicted and showed high similarity to those of Streptococcus thermophilus phage 2972 introns. An additional finding was differential superinfection inhibition between the two phages that corresponded with differences in nucleotide sequence and overall gene content within the lysogeny module. We conducted phylogenetic analyses on all known Siphoviridae, which showed PH15 and CNPH82 clustering with Staphylococcus aureus, creating a novel clade within the S. aureus group and providing a higher overall resolution of the siphophage branch of the phage proteomic tree than previous studies. Until now, no S. epidermidis phage genome sequences have been reported in the literature, and thus this study represents the first complete genomic and molecular description of two S. epidermidis phages.

Base Sequence↗

PubMed1972

Isolation of the rec mutants in Staphylococcus aureus.

A histidine auxotroph (his-) of Staphylococcus aureus MS3937 and mutants sensitive to ultraviolet (UV) irradiation were obtained. The UV-sensitive mutants were found also to be sensitive to N-methyl-N'-nitro-N-nitrosoguanidine and mitomycin C, and their sensitivity was accounted for by a defect in deoxyribonucleic acid repair. Transduction of either chromosomal or plasmid markers to UV-sensitive mutants showed that these staphylococcus mutants are of the recA (reckless) type mutants as reported in Escherichia coli and Salmonella typhimurium; therefore the UV-sensitive mutants (uvr-) were renamed recombination-deficient mutants (rec-). The biochemical and genetic properties of these mutants are described, and their usefulness for studies of staphylococcal plasmids is discussed.

Carbon Isotopes↗