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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
Tue Jan 01 2013
Journal Name
The Iraqi Journal Of Veterinary Medicine
Detection of methicillin or multidrug resistant Staphylococcus aureus (MRSA) in locally produced raw milk and soft cheese in Baghdad markets.
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In order to investigate the presence of methicillin or multidrug resistant Staphylococcus aureus in food-chain especially Cows raw milk and white raw soft cheese and its whey, a total of 30 samples were collected randomly from different markets in Baghdad Province during December 2012 till February 2013, in which samples were analyzed by a standard isolation protocols of food microbiology with some modification processing by new, modern and rapid technology tools such as chromogenic medium Baird-Parker agar, Electronic RapIDTM Staph Plus Code Compendium Panel System (ERIC®) Dryspot Staphytect Plus and Penicillin Binding Protein (PBP2') Plus assays; as well as, studying the susceptibility of isolates to different selected antibiotics. The r

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Publication Date
Wed Oct 31 2018
Journal Name
Iraqi Journal Of Science
Study the Expression of msrA,msrB and linA/linA’ genes in Presence of Some Antibiotics in Methicillin Resistance Staphylococcus aureus
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Eight isolates of methicillin resistance Staphylococcus aureus(MRSA) (SA40,SA32,SA30,SA13,SA10,SA36,SA3 and SA7) with different resistance phenotypes  to macrolides , lincosamides and streptogramins Were used to detect theexpression of msrA, msrB, and linA/linA’genesby using  real time polymerase chain reaction before and after treatment with antibiotics (erythromycin , clarithromycin , clindamycin and lincomycin) calibrated with triosphosphateisomerase.There highst expression of these genes was after 18 hours. It was  an induction in the expression of msrA gene in isolates (SA40,SA32,SA30 and SA13) in presence of erythromycin,however,the  isolates showed reduction in expression l

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Publication Date
Thu Jun 30 2016
Journal Name
Al-kindy College Medical Journal
Antibacterial activity of Trigonella Foenum- groecum essential oil against skin infection with Staphylococcus aureus: In vitro and in vivo studies
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Background: Multi- drug resistant (MDR) Staphylococcus aureus infections have become a major public health concern in both hospital and community settings.Objective: to investigate the antibacterial activity of T. Foenum- groecum essential oil against skin infection with S. aureus and to study probable synergistic activity in combination with Clindamycin.Type of the study: Cross-sectional study.

Methods: Antibacterial activity of T. Foenum- groecum essential oil extract (1.2gm/100 µl) was investigated in multi- drug resistance (MDR) Staphylococcus aureus specimen isolated from patients with skin infection in Baghdad. T. Foenum- groecum use externally for cellulites and skin inflammation due to the presence of diosgenin .fast liq

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Publication Date
Wed Feb 01 2023
Journal Name
Tropical Journal Of Natural Product Research
Expression of algD Gene in Single- and Dual-Species Biofilms of Pseudomonas aeruginosa and Staphylococcus aureus Under Starvation Stress
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Dual-species biofilms of Pseudomonas aeruginosa and Staphylococcus aureus generate difficult-to-treat illnesses. Nutrition stress in biofilms affects physiology, microbial metabolism, and species interactions, impacting bacteria growth and survival. Furthermore, the function of alginate, which is encoded by the algD gene, in the production of biofilms has been established. The present study aimed at investigating the impact of starvation on algD gene expression in single-species biofilm of P. aeruginosa and dual-species biofilms of P. aeruginosa and S. aureus from hospital sewage. A total of six P. aeruginosa and six S. aureus isolates were obtained from the microbiology laboratory at the Department of Biology, College of Science, Universit

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Publication Date
Sun Oct 22 2023
Journal Name
Iraqi Journal Of Science
*E mail:[email protected] 1802 The Role of Antibiotic-Killed Staphylococcus aureus and Its DNA to Cause Arthritis in Rats
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The purpose of this study is to investigate the capability of bacterial DNA compared to bacterial lysate in stimulating arthritis using rat model. One hundred mid-stream urine specimens were collected during November 2012 to January 2013, from patients suffering from urinary tract infections attending hospitals in Baghdad, Iraq. Susceptibility of Staphylococcus aureus isolates to antibiotics was examined. Twenty five isolates were identified as S. aureus and they developed multi drug resistance. S. aureus S1 lyaste and its DNA were intra-articulary injected in rats. The levels of IL-6, anti-ds DNA Ab and leukocytes count were measured. In general, IL-6, anti-ds DNA Ab and leukocytes count were significantly higher in sera of rats injecte

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Publication Date
Sun Dec 05 2010
Journal Name
Baghdad Science Journal
Effect of Granulocyte-colony stimulating factor with or without Moxifloxcacin therapy on capsulated Staphylococcus aureus infection in neutropenic mice
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Twenty bacterial isolates were identified as Staphylococcus aureus collected from wounds and catheters related infections. A capsulated S. aureus isolate was chosen after performing serum soft agar test, for this study Neutropenic mice were challenged with capsulated S. aureus ,and the effect of G-CSF with or without moxifloxacin was studied. The results indicated that the addition of G-CSF to moxifloxacin therapy have a synergistic effect in the killing of the bacteria, while when each G-CSF and moxifloxacin were used seperately have a similar effect on bacterial killing. It was found that the moxifloxacin has the same activity as G_CSF but is less costly than the latter one.

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Publication Date
Tue Mar 30 2021
Journal Name
Iraqi Journal Of Science
A Molecular Study of Toxic Shock Syndrome Toxin gene (tsst-1) in β-lactam Resistant Staphylococcus aureus Clinical Isolates
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Three hundred and sixty different samples were collected from different sources, including wound, burn, nasal, and oral swabs from several hospitals in Baghdad. A number of 150 (53%) Staphylococcus aureus samples were isolated and identified among a total of 283 samples. Then, the spread of the Toxic Shock Syndrome Toxin-1 gene (tsst-1) was investigated in β-lactamase resistant S. aureus. According to the source of samples, the distribution of S. aureus  isolates was found to be significantly higher (p < 0.01) in wound samples as compared to other sources. According to the age, a highly significant  distribution (p < 0.01) was recorded in the age group of 15-30 years,

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Publication Date
Wed Oct 31 2018
Journal Name
Iraqi Journal Of Science
The Biological Activity of Eucalyptus rostrata Leaves Extraction against E.coli and Staphylococcus aureus isolated from Iraqi Patients
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The inhibitory effect of Eucalyptus rostrata leaves extraction was investigated on multiple-antibiotic-resistant pathogenic bacteria (E.coli and S. aureus), isolated from Iraqi patients. The minimum inhibitory concentrations in a final concentration of 10 mg/ml. Tow fold dilutions was done from (12.5- 100) mg/ ml to examine the antibacterial effect of different concentrations of the plant extract on both bacteria. The study results revealed that Eucalyptus rostrata extract has a potential inhibitory effect on both gram negative and gram positive species. The current study supports the traditional approach of using Eucalyptus rostrata leaves extraction in treatment trails against bacterial infections.

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Publication Date
Sun Apr 29 2018
Journal Name
Iraqi Journal Of Science
The anti- Leishmaniasis activity of Purified Bacteriocin Staphylococcin and Pyocin Isolated from Staphylococcus aureus and Pseudomonas aeruginosa
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Tropical illnesses caused by parasites proceed to cause socioeconomic devastation that reverberate worldwide protozoan parasites, like Leishmania. This parasite has an enormous public health problem in many countries. There is a growing requisite for new control methods for many of these illnesses due to the increasing drug resistance showed by the parasites and problems with drug poisonousness. In this study, fifty-five patients (burns and wounds) were collected from patients from Al-Yarmouk Hospital and Teaching Baghdad Hospital during the period from November, 2015 to January, 2016. Cultural and morphological characteristic examination, biochemical tests were conducted and confirmed the diagnosis by antibiotics sensitivity te

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Publication Date
Sun Jun 07 2009
Journal Name
Baghdad Science Journal
Changes of the susceptibility of Staphylococcus aureus bacteria to the local therapeutic agent by using Nitrogen laser
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This study involves the investigation of the effect of nitrogen laser with 337.1 nm wavelength on the sensitivity of Staphylococcus aureus bacteria by using local therapeutic due to burns. Thirty six isolate of Staphylococcus aureus bacteria were isolated from 25 patients suffering from sever burns, each isolate of bacteria was irradiated with nitrogen laser at (5, 10, 15 and 30) pulses/second repetition rates for 1, 5, 10, 20 and 30 minutes for each repetition rate. The effects of nitrogen laser on the local therapeutics sensitivity of bacteria were obtained using Kirby Baur method. Changes in the sensitivity of bacteria to local therapeutics (Tetracyclin, Chloramphenicol, Flumizin and Fucidin) occur at high repetition rate(30 pulses/seco

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