Search results for "Staphylococcus"
showing 10 items of 371 documents
A new fear in wine: Isolation of Staphylococcus epidermidis histamine producer
2016
Abstract Biogenic amines (BAs) are undesirable compounds in all foods and beverages because they may induce food-borne intoxications when consumed at high concentrations. The aim of this study was to identify the organism responsible for the synthesis of histamine in a Tempranillo red wine from Ribera de Duero D.O. (Denomination of origin), Spain. Bacteria present in wines after malolactic fermentation were isolated, identified and typed. Four strains of the species Oenococcus oeni and two strains of Staphylococcus epidermidis were found. None of the O. oeni strains produced histamine, cadaverine or putrescine, but one of the S. epidermidis strains (Pa) was able to produce all three in synt…
Identification and structural characterization of LytU, a unique peptidoglycan endopeptidase from the lysostaphin family
2017
AbstractWe introduce LytU, a short member of the lysostaphin family of zinc-dependent pentaglycine endopeptidases. It is a potential antimicrobial agent for S. aureus infections and its gene transcription is highly upregulated upon antibiotic treatments along with other genes involved in cell wall synthesis. We found this enzyme to be responsible for the opening of the cell wall peptidoglycan layer during cell divisions in S. aureus. LytU is anchored in the plasma membrane with the active part residing in the periplasmic space. It has a unique Ile/Lys insertion at position 151 that resides in the catalytic site-neighbouring loop and is vital for the enzymatic activity but not affecting the …
A new class of phenylhydrazinylidene derivatives as inhibitors of Staphylococcus aureus biofilm formation
2016
In the struggle against the emergence of the antibiotic resistance, new molecules targeting biofilm formation could be useful as adjuvant of conventional antibiotics. This study focused on a new class of 2-phenylhydrazinylidene derivatives as antivirulence agents. The compound 12e showed interesting activities against biofilm formation of all tested Staphylococcus aureus strains with IC50 ranging from 1.7 to 43 µM; compounds 12f and 13a resulted strong inhibitors of S. aureus ATCC 6538 and ATCC 29213 biofilm formation with IC50 of 0.9 and 0.8 µM, respectively. A preliminary study on the mechanism of action was carried on evaluating the inhibition of sortase A transpeptidase. Compound 12e re…
The Management of Staphylococcal Toxic Shock Syndrome. A Case Report
2016
Abstract Staphylococcal toxic shock syndrome (TSS) is most frequently produced by TSS toxin-1 (TSST-1) and Staphylococcal enterotoxin B (SEB), and only rarely by enterotoxins A, C, D, E, and H. Various clinical pictures can occur depending on severity, patient age and immune status of the host. Severe forms, complicated by sepsis, are associated with a death rate of 50-60%. The case of a Caucasian female infant, aged seven weeks, hospitalized with a diffuse skin rash, characterized as allergodermia, who initially developed TSS with axillary intertrigo, is reported. TSS was confirmed according to 2011 CDC criteria, and blood cultures positive for Methicillin-sensitive Staphylococcus aureus (…
Staphylococcus aureus bloodstream infection in patients with prosthetic joint included in the prospective VIRSTA cohort study: frequency and time of …
2019
International audience; Among 143 patients of the VIRSTA cohort study with Staphylococcus aureus bacteremia and an arthroplasty implanted for more than a year, S. aureus periprosthetic joint infection was observed in 19%. Signs of infection (pain and swelling) were always present, in median 1 day (range, 0-21 days) after onset of bacteremia. Staphylococcus aureus has both a high potential for metastatic infection and a high affinity for foreign material. Possible prosthesis infection is of clinical concern in all patients with preexisting prosthetic materials experiencing S. aureus bloodstream infection (SAB). Prosthetic joints are especially prone to infection during the course of bacterem…
The VIRSTA score, a prediction score to estimate risk of infective endocarditis and determine priority for echocardiography in patients with Staphylo…
2016
International audience; Objectives - To develop and validate a prediction score, to quantify, within 48 h of Staphylococcus aureus bacteremia (SAB) diagnosis, the risk of IE, and therefore determine priority for urgent echocardiography. Methods - Consecutive adult patients with SAB in 8 French university hospitals between 2009 and 2011 were prospectively enrolled and followed-up 3 months. A predictive model was developed and internally validated using bootstrap procedures. Results - Among the 2008 patients enrolled, 221 (11.0%) had definite IE of whom 39 (17.6%) underwent valve surgery, 25% of them within 6 days of SAB diagnosis. Ten predictors independently associated with IE were used to …
Structural and functional insights into lysostaphin–substrate interaction
2018
Lysostaphin from Staphylococcus simulans and its family enzymes rapidly acquire prominence as the next generation agents in treatment of S. aureus infections. The specificity of lysostaphin is promoted by its C-terminal cell wall targeting domain selectivity towards pentaglycine bridges in S. aureus cell wall. Scission of these cross-links is carried out by its N-terminal catalytic domain, a zinc-dependent endopeptidase. Understanding the determinants affecting the efficiency of catalysis and strength and specificity of interactions lies at the heart of all lysostaphin family enzyme applications. To this end, we have used NMR, SAXS and molecular dynamics simulations to characterize lysostap…
New Thiazole Nortopsentin Analogues Inhibit Bacterial Biofilm Formation.
2018
New thiazole nortopsentin analogues were conveniently synthesized and evaluated for their activity as inhibitors of biofilm formation of relevant Gram-positive and Gram-negative pathogens. All compounds were able to interfere with the first step of biofilm formation in a dose-dependent manner, showing a selectivity against the staphylococcal strains. The most active derivatives elicited IC50 values against Staphylococcus aureus ATCC 25923, ranging from 0.40&ndash
The antimicrobial activity of honey and propolis extracts from the central region of Romania
2021
Abstract Honey and propolis from Apis mellifera (bees) are products that have been used due to their multiple biological properties. The antimicrobial activity of 10 honey samples of known origin and 4 propolis extracts gathered from the same beekeepers located in Transylvania, Romania, were used against certain microorganisms: Escherichia coli, Staphylococcus aureus, Bacillus cereus, Pseudomonas aeruginosa and Candida albicans. The study also investigated the positive interaction of propolis aqueous extracts when used with poly-floral honey against the same microorganisms. The most sensitive to the activity of honey samples was the S. aureus strain (the largest inhibition area 18 mm) for p…
Control of the bifunctional O 2 ‐sensor kinase NreB of Staphylococcus carnosus by the nitrate sensor NreA: Switching from kinase to phosphatase state
2019
The NreB-NreC two-component system of Staphylococcus carnosus for O2 sensing cooperates with the accessory nitrate sensor NreA in the NreA-NreB-NreC system for coordinated sensing and regulation of nitrate respiration by O2 and nitrate. ApoNreA (NreA in the absence of nitrate) interacts with NreB and inhibits NreB autophosphorylation (and activation). NreB contains the phosphatase motif DxxxQ. The present study shows that NreB on its own was inactive for the dephosphorylation of the phosphorylated response regulator NreC (NreC-P), but co-incubation with NreB and NreA stimulated NreC-P dephosphorylation. Either the presence of NreA · NO 3 - instead of apoNreA or mutation of the phosphatase m…