[en] The use of Staphylococcus aureus for the radio-immunoassay of C-type virus polypeptides provided very specific results and proved to present several advantages over the classical methods of precipitation of immune complexes

[en] SOS functions induced by ultraviolet (UV) radiation were studied using S. aureus and S. epidermidis. Comparing the results obtained from these two organisms with those described in the literature for E. coli allows us to conclude: the difference in UV sensibility between the lysogenic and non-lysogenic strains of Staphylococcus is extremely large; the dose of UV radiation which results in the maximum induction of the lysogenic strains lead to 99% inactivation of the lysogenic strains; the kinetics of prophage liberation in lysogenic cultures of Staphylococcus is more rapid than those described for E. coli; the dose of UV radiation is much lower than the dose described for E. coli; the maximum W-reactivatio and W-mutagenesis are obtained immediately after the irradiation or within the 15 minutes allowed for the phage adsorption. (author)

[en] Objectives: To compare the in vitro activities of vancomycin and linezolid against methicillin resistant Staphyloccus aureus in our set up to help in formulating a better empirical treatment and reduce the emergence of vancomycin resistant Staphylococcus aureus. Methods: The study was conducted over a period of 6 months(July 1, 2009 - Dec 1, 2009). Fifty Methicillin resistant Staphylococcus aureus isolated from the clinical isolates of Military Hospital Rawalpindi were subjected to the determination of Minimum inhibitory concentrations of linezolid and vancomycin using E-strips. Results: All the isolated organisms were uniformly susceptible to both the antibiotics. Vancomycin showed higher minimum inhibitory concentrations (MICs) as compared to linezolid MICs. Conclusion: This study suggests that linezolid and vancomycin have similar in vitro efficacy for methicillin resistant Staphyloccus aureus infections. (author)

[en] A sensitive double-antibody radioimmunoassay for staphylococcal enterotoxins A and B is described. The separation of the primary antigen-antibody complex of enterotoxin A and B was achieved with an anti-rabbit gamma globulin from goats. Radioiodinated aggregate fractions of staphylococcal enterotoxins exhibited reduced immunological activity and showed little competition with non-radioactive enterotoxin. The radioimmunoassay was successfully applied for the quantitation of enterotoxins in food. (author)

[en] Highlights: • Focused library screen identifies bacteriostatics of many pathogens. • Staphylococcus aureus' growth is inhibited at IC₅₀ = 30–150 μM. • Proteus mirabilis is killed by similar compound chemical structures of compounds are different from known antibacterials. Staphylococcus aureus is a human pathogen rapidly becoming a serious health problem due to ease of acquiring antibiotic resistance. To help identify potential new drug candidates effective against the pathogen, a small focused library was screened for inhibition of bacterial growth against several pathogens, including S. aureus. At least one of the compounds, Compound 10, was capable of blocking bacterial growth of S. aureus in a test tube with IC₅₀ = 140 ± 30 μM. Another inhibitor, Compound 7, was bacteriostatic against S. aureus with IC₅₀ ranging from 33 to 150 μM against 3 different strains. However, only Compound 7 was bactericidal against P. mirabilis as examined by electron microscopy. Human cell line toxicity studies suggested that both compounds had small effect on cell growth at 100 μM concentration as examined by MTT assay. Analysis of compounds’ structures showed lack of similarity to any known antibiotics and bacteriostatics, potentially offering the inhibitors as an alternative to existing solutions in controlling bacterial infections for selected pathogens.

[en] Highlights: • gp44 is a minor capsid protein of Staphylococcus aureus bacteriophage 80α. • gp44 is vital for productive 80α infection, but not for transduction of plasmids. • gp44 does not affect phage assembly, packaging or DNA ejection. • gp44 is an ejection protein that acts in the host cell post DNA injection. • gp44 promotes progression to lytic growth, and is required for lysogenization. Many staphylococcal bacteriophages encode a minor capsid protein between the genes for the portal and scaffolding proteins. In Staphylococcus aureus bacteriophage 80α, this protein, called gp44, is essential for the production of viable phage, but dispensable for the phage-mediated mobilization of S. aureus pathogenicity islands. We show here that gp44 is not required for capsid assembly, DNA packaging or ejection of the DNA, nor for generalized transduction of plasmids. An 80α Δ44 mutant could be complemented in trans by gp44 expressed from a plasmid, indicating that gp44 plays a post-injection role in the host. Our results show that gp44 is an ejection (pilot) protein that is involved in deciding the fate of the phage DNA after injection. Our data are consistent with a model in which gp44 acts as a regulatory protein that promotes progression to the lytic cycle.

[en] The authors have examined a method to detect infections using radiolabeled antibodies. Staphylococcal endocarditis was chosen as a model because it poses a common clinical diagnostic problem. The experiments demonstrate that biologically active antibodies may be extracted and efficiently labeled by a relatively simple process. This has the potential to make the specificity of the in vivo antigen-antibody reaction available through the use of autologously extracted, labeled γ-globulin

[en] The authors' findings indicate that irradiation confers no advantage over heat processing in respect of bacterial toxins (clostridium botulinum, neurotoxin A and staphylococcal enterotoxin A). It follows that irradiation at doses less than the ACINF recommended upper limit of 10 kGy could not be used to improve the ambient temperature shelf life on non-acid foods. (author)

No abstract available

[en] The double-antibody radioimmunoassay of enterotoxins A, B, and C was modified by the addition of aqueous polyethylene glycol which precipitated double-antibody bound staphylococcal enterotoxins with little or no precipitation of free enterotoxin. The precipitate formed appeared as a thin coating at the bottom of the test tube and was not removed by aspiration. The procedure obviates the need for normal rabbit serum and for an additional wash of the precipitate. (author)