Antimicrobial Activity of the Quinoline Derivative HT61 against Staphylococcus aureus Biofilms.

Staphylococcus aureus biofilms are a significant problem in health care settings, partly due to the presence of a nondividing, antibiotic-tolerant subpopulation. Here we evaluated treatment of S. aureus UAMS-1 biofilms with HT61, a quinoline derivative shown to be effective against nondividing Staphylococcus spp. HT61 was effective at reducing biofilm viability and was associated with increased expression of cell wall stress and division proteins, confirming its potential as a treatment for S. aureus biofilm infections

The Frequency of MRSA carriers in health care workers in Gorgan, North of Iran

Methicillin resistant Staphylococcus aureus (MRSA) is one of the most important pathogen in hospitals. Healthcare personnel are the main source of nosocomial infections and identification and control of MRSA carriers can reduce incidence of infections. The aim of this study was to determine the frequency of methicillin resistant Staphylococcus aureus (MRSA) and their antibiotic susceptibility profile among healthcare workers in Gorgan located in northern Iran. Three hundred and thirty three of healthcare workers were participated in this cross-sectional study in 2010. Samples were taken with sterile cotton swabs from both anterior nares. Swabs were plated onto Mannitol salt agar. S. aureus were identified by Gram stain, Catalase, Coagulase and DNase tests. MIC (micro dilution broth) method was used to determine resistance of strains to methicillin. Antimicrobial susceptibility pattern to other antibiotics was performed by diffusion method. Frequency of S. aureus and MRSA carriers among healthcare workers was 24% (80.33) and 3% (10.33) respectively. MIC of isolates was varied between 0.5 and 65.31 (39%) of cases were showed MIC of intermediate that ranged between 4 and 8. Penicillin and Imipenem resistance were seen in 97.5% and 1.4% of isolated S. aureus strains, respectively. Frequency of S. aureus carriers in healthcare workers in our area was median in compare with other region in Iran but the MRSA carriage in healthy staff was lower than most part of Iran. It would be considering to monitor healthy carrier staff because of high rate intermediate MIC in this group to prevent conversion to MRSA

Phenotypic and Genotypic Characteristics of Methicillin-Resistant Staphylococcus aureus (MRSA) Related to Persistent Endovascular Infection.

Persistent methicillin-resistant Staphylococcus aureus (MRSA) bacteremia (PB) represents an important subset of S. aureus infection and correlates with poor clinical outcomes. MRSA isolates from patients with PB differ significantly from those of resolving bacteremia (RB) with regard to several in vitro phenotypic and genotypic profiles. For instance, PB strains exhibit less susceptibility to cationic host defense peptides and vancomycin (VAN) killing under in vivo-like conditions, greater damage to endothelial cells, thicker biofilm formation, altered growth rates, early activation of many global virulence regulons (e.g., sigB, sarA, sae and agr) and higher expression of purine biosynthesis genes (e.g., purF) than RB strains. Importantly, PB strains are significantly more resistant to VAN treatment in experimental infective endocarditis as compared to RB strains, despite similar VAN minimum inhibitory concentrations (MICs) in vitro. Here, we review relevant phenotypic and genotypic characteristics related to the PB outcome. These and future insights may improve our understanding of the specific mechanism(s) contributing to the PB outcome, and aid in the development of novel therapeutic and preventative measures against this life-threatening infection

Molecular Genetic Typing of Staphylococcus aureus from Cows, Goats, Sheep, Rabbits and Chickens

End of project reportsS. aureus can also cause a number of infections in animals such as tick-associated pyaemia in lambs, staphylococcosis in rabbits, septicaemia, abscesses and chondronecrosis in chickens and pneumonia and osteomyelitis complex in turkeys. S. aureus is the most frequent cause of bovine mastitis, a disease that is of economic importance worldwide (Beck et al., 1992). Typically staphylococcal mastitis is chronic in nature, with subclinical mastitis being the most common form

Interplay of Staphylococcal and Host Proteases Promotes Skin Barrier Disruption in Netherton Syndrome.

Netherton syndrome (NS) is a monogenic skin disease resulting from loss of function of lymphoepithelial Kazal-type-related protease inhibitor (LEKTI-1). In this study we examine if bacteria residing on the skin are influenced by the loss of LEKTI-1 and if interaction between this human gene and resident bacteria contributes to skin disease. Shotgun sequencing of the skin microbiome demonstrates that lesional skin of NS subjects is dominated by Staphylococcus aureus (S. aureus) and Staphylococcus epidermidis (S. epidermidis). Isolates of either species from NS subjects are able to induce skin inflammation and barrier damage on mice. These microbes promote skin inflammation in the setting of LEKTI-1 deficiency due to excess proteolytic activity promoted by S. aureus phenol-soluble modulin α as well as increased bacterial proteases staphopain A and B from S. aureus or EcpA from S. epidermidis. These findings demonstrate the critical need for maintaining homeostasis of host and microbial proteases to prevent a human skin disease

Low MRSA prevalence in horses at farm level

Background: In Europe, methicillin-resistant Staphylococcus aureus (MRSA) belonging to the clonal complex (CC) 398 has become an important pathogen in horses, circulating in equine clinics and causing both colonization and infection. Whether equine MRSA is bound to hospitals or can also circulate in the general horse population is currently unknown. This study, therefore, reports the nasal and perianal MRSA screening of 189 horses on 10 farms in a suspected high prevalence region (East-and West-Flanders, Belgium). Results: Only one horse (0.53%) from one farm (10%) tested positive in the nose. It carried a spa type t011-SCCmecV isolate, resistant to beta-lactams and tetracycline, which is typical for livestock-associated MRSA CC398. Conclusion: In the region tested here, horses on horse farms seem unlikely to substantially contribute to the large animal associated ST398 MRSA reservoir present at intensive animal production units

In Vitro Inhibition Zone Test Of Binahong (Anredera Cordifolia) Towards Staphylococcus Aureus, Enterococcus Faecalis, Escherichia Coli, And Pseudomonas Aeruginosa

This is a true experimental research with post test-only control group design. The study was conducted to test the inhibitory zone of the Binahong leaf extract (Anredera cordifolia) against Staphylococcus aureus, Enterococcus faecalis, Escherichia coli, and Pseudomonas aeruginosa. Binahong leaf extract is prepared using maceration technique, by soaking it in a sealed jar for 24 hours with 95% methanol. Then subsequently filtered using a funnel with filter paper, and the filtrate is collected inside an erlenmeyer. The filtrate then concentrated using a rotavapor, this concentrated extract dissolved into aquadest with a concentration of 50 ppm, 100 ppm and 1000 ppm. By taking a few colonies with a sterile loop into a stock of Staphylococcus aureus, Enterococcus faecalis, Esherichia coli, Pseudomonas aeruginosa then scratch it into MH blood agar medium, and incubate it for 24 hours with a temperature of 370C. The next day, bacterial suspension was made in test tube, which already contains 0.9% NaCl. The suspension tturbidity is equivalent to 0.5 Mc Farland. Bacterial inhibition zone of binahong leaf extract (Anredera cordifolia) is tested using absorbance disc method or better known as the Kirby-Bauer method. First, pour 10 ml of agar medium (± 400C) into a cup (petridish) and then wait until it's cold. After the medium becomes solid, the suspension of bacteria Staphylococcus aureus, Enterococcus faecalis, Esherichia coli, and Pseudomonas aeruginosa are slowly smeared with sterile cotton sticks on the surface of the media. Soak the paper discs into binahong leaf extract (Anredera cordifolia) with concentrations of 50, 100, and 1000 ppm, for about 5 minutes, and placed it on the surface of the petridish, together with the positive control (amoxicillin) and negative control (aquadest). Then incubate it at 370C for 24 hours. The effectiveness of binahong leaf extract (Anredera cordifolia) inhibition zone, can be determined by measuring the diameter of clear zone around the paper using a sliding-term. Binahong leaf extract (Anredera cordifolia) zone of inhibition is negative, a very slight different is showed by the amoxicillin inhibition zone, for having a clear zone diameter of 28 mm for Staphylococcus aureus and Esherichia coli, and 21 mm for Enterococcus faecalis. This fact is probably caused by several things concerning the mechanism of action of a substance as an anti bacterial of the binahong leaf extract (Anredera cordifolia)

tmRNA - a novel high-copy-number RNA diagnostic target - its application for Staphylococcus aureus detection using real-time NASBA

A real-time nucleic acid sequence-based amplification assay, targeting tmRNA, was designed for the rapid identification of Staphylococcus aureus. The selectivity of the assay was confirmed against a panel of 76 Staphylococcus strains and species and 22 other bacterial species. A detection limit of 1 cell equivalent was determined for the assay. A chimeric in vitro transcribed internal amplification control was developed and included in the assay. Application of the assay in natural and artificially contaminated unpasteurized (raw) milk enabled detection of 1-10 CFUS. aureus mL(-1) in 3-4 h, without the need for culture enrichment. Staphylococcus aureus was detected in all artificially contaminated milk samples (n=20) and none of the natural milk samples (n=20). Microbiological analysis of the natural milk samples was performed in parallel according to ISO 6888-3 and confirmed the absence of S. aureus. The method developed in this study has the potential to enable the specific detection of S. aureus in raw milk in a significantly shorter time frame than current standard methods. The assay further demonstrates the usefulness of tmRNA/ssrA as a nucleic acid diagnostic target