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
The isolates of Staphylococcus aureus were isolated from patients with various infections in hospitals, the isolates were identified and accurately diagnosed by phenotypic examination and biochemical tests, as well Vitek-2, and then genetic detection and diagnosis of many of the pathogenic factors associated with Staphylococcus aureus using conventional polymerase chain reaction (PCR) and testing for association by antibiotic resistance and production of some toxins by Staphylococcus aureus. After performing analysis of statistical, it was set up that the correlation coefficient of the PCR technique using virulence genes, sensitivity test to antibiotics and other virulence factors were significant at p < 0.05, but was insignificant with the
... Show MoreIn this study, Staphylococcus aureus was found to be the causative agent of furunculosis in 64 (27.5%) out of 233 Iraqi patients presented with furunculosis. 16SrRNA gene was located in all isolates. Nevertheless, mecA and lukS-lukF genes were located in 60% and 4% of S. aureus isolates, respectively. Interestingly, the lukS-lukF carrying S. aureus isolates were mecA positive as well.
Background: Bacterial DNA released upon bacterial autolysis or killed by antibiotics, hence, many inflammatogenic reactions will be established leading to serious tissue damage. Aim: the present work aimed to elucidate the histopathological changes caused by prokaryotic (bacterial) DNA and eukaryotic (candidal) DNA. Materials and methods: twenty one Staphylococcus aureus and 36 Candida albicans isolates were isolated from UTI patients. Viable cells and DNA of the highest antibiotic sensitive isolates were injected, intraurethraly, in mice. Results were evaluated via histopathological examination. Results: Mildest reactions were obtained from mice challenged with viable C. albicans compared with those challenged with viable S. aureus. Dos
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This study investigates in vitro biofilm production. Presence of ica A and D genes in methicillin-resistant Staphylococcus aureus was evaluated for biofilm production by the microtiter plate method. Between December 2020 and October 2021, out of 215 clinical specimens were collected from patients with pulmonary fibrosis, pneumonia, bacteremia, chronic burns, deep wounds, urinary tract infection and catheterized patients. Out of which 45 MRSA isolates were identified by the susceptibility test utilizing cefoxitin and the occurrence of mecA gene for resistance for this antibiotic verified by polymerase chain reaction technique. A sensitivity test was conducted for five other antibiotics
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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 highe
Background: Suppression of quorum sensing (QS) that regulates many virulence factors, including antimicrobial resistance, in bacteria may subject the pathogenic microbes to the harmful consequences of the antibiotics, increasing their susceptibility to such drugs. Aim: The current study aimed to make an aqueous crude extract from the soil Proteus mirabilis isolate with the use of the gas chromatography-mass spectrometry (GC-MS) technique for its analysis, and then, study the impact of the extract on clinical isolates of Pseudomonas aeruginosa. Methods: Preparation of crude extracts from P. mirabilis (both organic and aqueous), which were then analyzed by GC-MS to detect the bioactive ingredients. Furthermore, the extract’s capability to i
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This study included collection of 100 specimens from patients in AL-Kindy Teaching Hospital and teaching laboratories of Medical City Hospitals in Baghdad during the period from August to December 2012 ,these specimens differed in their sources which included 19 nasal swab, 16 wound swab,27 burn swab, 7 pus, 15 sputum, 10 corneal swab and 6 urine . Only 38 (38%) isolates was identified as Staphylococcus. In this study, 29 isolates (76.3%) were coagulase-positive (COPS), while only 9 isolates(23.6%) were coagulase negative (CONS), from total 38 isolates of Staphylococci.
The distribution of Methicillin resistance among Staphylococcus spp. was investigated by disc diffusion method. In this study, 21 isolates (55.26%) showed resistant to
The resistance of Staphylococcus aureus to ciprofloxacin has complicated the problem of treating staphylococcal associated infections in which MRSA is the causative agent since ciprofloxacin was the drug of choice to treat such infections. Our study investigated the incidence of Ciprofloxacin resistant S. aureus isolates that were also methicillin resistant among Iraqi patients. The obtained bacterial isolates were tested for Ciprofloxacin resistance using agar dilution method and the sequence of gyrA and parC. The results revealed that about 8% of the isolated MRSA strains were Ciprofloxacin resistant and the resistance was due to mutation in gyrA rather than parC.
The resistance of Staphylococcus aureus to ciprofloxacin has complicated the problem of treating staphylococcal associated infections in which MRSA is the causative agent since ciprofloxacin was the drug of choice to treat such infections. Our study investigated the incidence of Ciprofloxacin resistant S. aureus isolates that were also methicillin resistant among Iraqi patients. The obtained bacterial isolates were tested for Ciprofloxacin resistance using agar dilution method and the sequence of gyrA and parC. The results revealed that about 8% of the isolated MRSA strains were Ciprofloxacin resistant and the resistance was due to mutation in gyrA rather than parC.
The study aimed to find an association between Type two diabetes mellitus (T2DM) patients, obesity and the rate of nasal carriage of Staphylococcus aureus (NCSA) producer of TSST-1 in patients with T2DM compared with non-diabetic control groups. T2DM patients and control subjects were selected from outpatient of "The Specialist Center for Diseases of Endocrine and Diabetes" in Baghdad. The subjects were divided into 4 groups: Group I included 21 obese T2DM patients; Group II included 20 lean T2DM patients; Group III included 20 obese as control group and Group IV included 21 lean as control group. The study included sample with size (n= 82), male and female, with the ages ranged from 35 to 75 years, and the patients were not on any kind
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