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Quorum Sensing in Staphylococcus aureus
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Staphylococci are common commensals in human beings, yet certain species are pathogenic. Staphylococcus aureus, particularly, is a very virulent human pathogen. The capacity of staphylococci to sense the density of bacterial cell, i.e., quorum, and thereafter respond via genetic modifications is attributable to one primary mechanism known as accessory gene regulator (Agr). Agr's extracellular signal is a peptide that is posttranslationally modified with a thiolactone molecule. Agr is in charge of the upregulation of numerous exotoxins and hydrolyzing enzymes, as well as the downregulation of many colonization determinants, under circumstances of high cell density. This modulation is critical for the scheduling synthesis of virulence determinants throughout the infection course and the establishment of acute illness, whereas low Agr activity is linked to persistent staphylococcal infections, such as biofilm development. Moreover, Staphylococcal Accessory Regulator Aِ (SarA) controls the establishment of biofilm in S. aureus that hinders the production of nuclease and protease via triggering the P2 and P3 promoters resulting in the activation of RNAII and RNAIII, respectively. SarA also endures the transcription of agrA and saeS, and many virulence determinants including hla, hlb, and hlg coding α-, β-, and γ-hemolysins, respectively. Upon the aforementioned facts, the present review will shed some light on the Quorum Sensing (QS) in S. aureus, particularly, the Agr and Sar systems and how these systems control the pathogenicity of this spe

Publication Date
Mon Jan 15 2018
Journal Name
Iraqi Journal Of Laser
Effect of 410 nm Diode Laser Irradiation on the Growth of Burn Wounds-associated Bacteria, Pseudomonas Aeruginosa and Staphylococcus Aureus
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The effect of 410nm with 100 mW output power and one centimetre spot size (0.128 W/cm2 power density) Diode laser irradiation at different exposure times on the growth of Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus was evaluated. Seventy swap samples were collected from burn and infected wounds of 35 patients admitted to the burn-wound unit in Al-Yarmouk Teaching Hospital in Baghdad during the period from December 2014 to February 2015. These bacteria were isolated and identified depending on their growth on selective media, cultural characteristics, Gram stain morphology and biochemical tests and finally were confirmed by Vitek 2 compact system test .Susceptibility of bacterial isolates to 15antibiotics

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Publication Date
Mon Dec 31 2018
Journal Name
Iraqi Journal Of Market Research And Consumer Protection
STUDYING THE EFFECT OF Proteinase K AND α-Amylase ON INHIBITION OF Staphylococcus aureus AND Klebsiella pneumoniae BIOFILM ISOLATE FROM URINARY TRACT INFECTION.: STUDYING THE EFFECT OF Proteinase K AND α-Amylase ON INHIBITION OF Staphylococcus aureus AND Klebsiella pneumoniae BIOFILM ISOLATE FROM URINARY TRACT INFECTION.
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The current study aimed to investigate the viability of biofilm formation klebsilla pneumoniae and Staphylococcus aureus. 440 urine samples were collected from patients suffering from urinary tract infection (UTI) from those who were admitted and visitors to Al-Ramadi Teaching Hospital, Al-Yarmouk Teaching Hospital, Al-Ramadi Teaching Hospital for women and children and , Teaching Laboratories in the Medical City for both genders for a period extended from 5 July, 2017 to 10 October, 2017. Samples were diagnosed by culturing them on a selective media and by biochemical testes , also, diagnosis was ensured by using VITEK-2 compact system. Results showed that K.pneumoniae isolation ratio was 17.1%(68) and S.aureus ratio was 13.1%(52). Thei

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Publication Date
Thu Apr 01 2021
Journal Name
Biochemical & Cellular Archives
Impacts of Starvation Stress on Biofilm Formation and expression of Virulence Genes in Mono-and Mixed-species cultures of Pseudomonas Aeruginosa and Staphylococcus aureus
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Staphylococcus aureus and Pseudomonas aeruginosa are the major globally distributed pathogens, which causes chronic and recalcitrant infections due to their capacity to produce biofilms in large part. Biofilm production represents a survival strategy in these species, allowing them to endure environmental stress by altering their gene expression to match their own survival needs. In this study, we co-cultured different clinical isolates of S. aureus and P. aeruginosa as mono- and mixed-species biofilms in a full-strength Brain Heart Infusion Broth (BHI) and in a 1000-fold diluted Brain Heart Infusion Broth (BHI/1000) using Microtiter plate assay and determination of colony-forming units. Furthermore, the effect of starvation stress on the e

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Scopus (2)
Scopus
Publication Date
Wed Jan 01 2020
Journal Name
Systematic Reviews In Pharmacy
Impacts of the alcoholic extract and essential oil of Thymus vulgaris L. Against the causative agent of acne formation (Staphylococcus aureus)
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Medicinal plant life have performed an integral role in the development of human lifestyle being used as resources for the manufacturing of contemporary medicines, antibiotics. Microorganisms are responsible for many issues in industry and remedy because of biofilm formation. This study aimed to take a look at the results of Thymus vulgaris alcoholic extract on Staphylococcus aureus the causative marketers of acne in human particularly the women. The extract was acquired mixing 25 g of Thyme powder with 350 ml of 80% ethanol for 6 hours at 40°. Antimicrobial activities of the plant extract and integral oil towards the S. aureus were decided using the agar diffusion technique. The consequences proven that special concentrations of alcoholic

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Scopus (5)
Scopus
Publication Date
Thu Feb 07 2019
Journal Name
Iraqi Journal Of Laser
The Effect of 532 nm Diode Pumped Solid State (DPSS) Laser in Combination with Safranin on the Growth of Pseudomonas aeruginosa and Staphylococcus aureus in Vitro
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The effect of 532nm Diode Pumped Solid State (DPSS) laser at power density of 5.234 W/cm2 on the growth of Gram-negative Pseudomonas aeruginosa and Gram-positive Staphylococcus aureus was evaluated. These bacteria were isolated from samples taken from burn and infected wound areas of 55 patients admitted to the burn-wound unit in Al-Kindy teaching hospital in Baghdad during the period from October 2012 to March 2013. Each isolate was identified using microscopic, cultural and biochemical methods. A standard bacterial suspension was prepared for each isolate. Serial dilutions were then prepared and a dilution of 10-5 was selected. Irradiation experiments included four groups: (L-P-) bacterial suspension in saline solution, (L-P+) bacteria

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Publication Date
Thu Apr 28 2022
Journal Name
Iraqi Journal Of Science
Isolation and identification of Staphylococcus aureus, Listeria monocytogenes, E. coli O157:H7 and Salmonella specious from raw beef and lamb meat in Baghdad by PCR.
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The study designed to determine the distribution of a major important food pathogens including Staphylococcus aureus , Listeria monocytogenes, E. coli O157:H7 and Salmonella spp from raw beef and lamb meat by using multiplex pcr . A total of 90 raw beef and lamb meat samples were collected from different butcher's shops in Al-Karkh side of Baghdad city and analyzed for the presence of these types of bacteria and their susceptibilities to some antibiotics was investigated ,the results showed that the prevalence of S. aureus (5.6%), L. monocytogenes (3%), E. coli O157:H7 (7.8 %) and Salmonella spp (5.6%) from the total samples .The result of the susceptibility test showed that S. aureus isolates were susceptible to Amikacin (80%) ,while L.

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Publication Date
Thu Nov 30 2023
Journal Name
Iraqi Journal Of Science
Study of Optical, Structural and Morphology Properties of Tin Oxide Nanoparticles by Pulse Laser Ablation and its Effect on Bacteria Staphylococcus aureus
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     Tin oxide (Sn) nanoparticles were prepared by pulsed laser ablation (PLA) method at different laser energies (400-700mJ). (UV, XRD, AFM, SEM, EDS) methods were employed to determine the properties of nanomaterials. The optical properties showed that the energy gap decreased with increasing laser power; the structural properties showed the relationship between density and angle; Miller's coefficients for net angles were determined and the morphology properties showed the element's surface shape and surface roughness. Also, Tin oxide nanoparticles with added to Staphylococcus aureus bacteria isolated from the ear and cultured by striking method on nutrient agar to know the effect of tin oxide nanoparticles on the growth o

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Crossref
Publication Date
Wed Oct 09 2019
Journal Name
International Journal Of Drug Delivery Technology
The comparative study among the MRSAcin, Nisin A and vancomycin, on biofilm formation by Methicillin resistance Staphylococcus aureus isolated from food sources.
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Biofilms formation by pathogens microbial Control considered important in medical research because it is the hazarded virulence factor leading to becoming difficult to treat because of its high resistance to antimicrobials. Glycopeptide antibiotic a (Vancomycin) and the commercial bacteriocin (Nisin A) were used to comparative with purification bacteriocin (MRSAcin) against MRSA biofilm. One hundred food samples were collected from Baghdad markets from July 2016 to September 2016, including (cheese, yogurt, raw milk, fried meat, grilled meat, and beef burger). All samples were cultures; S. aureus was confirmation by macroscopic culture and microscopic examination, in addition to biochemical tests. Methicillin resistance S. asureus (

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Scopus (7)
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Publication Date
Sun Dec 09 2018
Journal Name
Baghdad Science Journal
Application of Randomly Amplified Polymorphic DNA (RAPD) Technique to Estimate Genetic Distance among Some Methicillin Resistant Staphylococcus aureus Isolated from Different Iraqi Hospitals
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Methicillin resistant Staphylococcus aureus (MRSA) is one of the principal nosocomial causative agents. This bacterium has the capability to resist wide range of antibiotics and it is responsible for many diseases like skin, nose and wounds infection. In this study, randomly amplified polymorphic DNA (RAPD)-PCR was applied with ten random primers to examine the molecular diversity among methicillin resistant Staphylococcus aureus (MRSA) isolates in the hospitals and to investigate the genetic distance between them. 90 Isolates were collected from clinical specimens from Iraqi hospitals for a total of 90 isolates. Only 10 strains (11.11%) were found to be MRSA. From these 10 primers, only 9 gave clear amplification products. 91 fragment l

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Publication Date
Thu Feb 03 2022
Journal Name
Biologia
Developing multiplex PCR for the rapid and simultaneous detection of Staphylococcus aureus, Pseudomonas aeruginosa and Klebsiella pneumoniae associated with sheep respiratory tract infections
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Respiratory tract infections in sheep are among the important health problems that affect all sheep ages around the world. Nine bacterial isolates obtained from sheep with respiratory tract infections were selected to be used in the current study. The isolates included 3 Staphylococcus aureus, 4 Klebsiella pneumoniae, and 2 Pseudomonas aeruginosa. Following the primers design by the Primer3Plus software tool and optimization of the conventional polymerase chain reaction (PCR), the primers were validated for their use in the multiplex PCR experiments. The MFEprimer program was used to check the suitability of the primer set combinations for multiplex PCR. The MFEprimer software was successful in designing the multiplex-PCR experiments and de

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Scopus (3)
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