The emergence and spread of methicillin-resistant Staphylococcus aureus (MRSA) was a public health problem worldwide that causes nosocomial and community infections. Forty three isolates (71.66%) were characterized as S.aureus, were isolated from 60 different clinical specimens (blood, nose, wound, urine and vaginal) collected from patients from different hospitals of Baghdad. All isolates were resistant (100%) to Aztreonam, Carbenicillin, Cifixime, Cefoxitin, Ceftazidime, and showed high resistance to each of Methicillin, Oxacillin, Ampicillin and Penicillin . the MRSA isolates were typed based on (SCCmec) typing ,the result revealed that SCCmecIVa was the most common in isolates (41.86%), following type IVc (20.93%), type II(16.27%). Virulence factors were identified to detect genes encoding for Hlg,Pvl,ClfA,Tsst-1 and Eta, and the result showed the most prevalent gene was hlg (65.11%), following pvl (53.48%), clfA (51.16%), tsst-1(18.60%),eta (11.62%). The virulence genes profiles were observed, and the most frequent was clfA-hlg-pvl (23.25%), clfA-hlg-pvl-tsst-1 (6.97%),clfA-hlg-tsst-1(4.65%).Analysis of genetic similarity relationship, showed the isolates of S.aureus were classified into two main clusters . This result indicates that there a diversity in virulence genes profiles among MRSA isolates according to SCCmec types, and SCCmec IVa carried hlg, pvl , clfA genes was the most prevalent in Baghdad hospital isolates .
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
... Show MoreMRSA is one of the major pathogens in hospitals and the community, which have the ability to produce biofilm as a virulence factor, the impact of chalcone on biofilm formation, the synergism effect of chalcone and antibiotic in both in vitro and in vivo experiments, the gene expression of virulence genes (srtA, fnbA, fnbB) before and after treatment of it on MRSA biofilm cells in vitro, all these were the prime aims of this study. Chalcone at MBIC (20 μg/ml), significantly reduced the biofilm formation to 21.45% and at sub MBIC (15 μg/ml) to 36.58 %. While, Chalcone at MIC(5 μg/ml) reduced MRSA planktonic cells to 49.61%. Susceptibility of MRSA isolates against eight antibiotics showed that all isolates were sensitive to vancomycin and n
... Show MoreUnder high concentrations of antibiotics, a fraction of the bacterial population exhibits a phenomenon known as persistence. Toxin- system (TA system) has been reported to be involved in the formation of E. coli, Mycobacterium, and S. aureus persisters. In this study, the ability of thirty Iraqi isolates of MRSA to form in vitro persister cells after exposure to three different antibiotics (Ceftriaxone 30 µg, Mecillinam 10 µg, and Mupirocin 20 µg) was examined by TD test. Additionally, efflux pump inhibitor [Fluphenazine 0.25 mg/ml] was combined with the antibiotic that triggered persister formation. The distribution of mazEF and yefM-yoeB (Type II TA system) in the tested isolates was detected by PCR. 91% of Mupirocin su
... Show MoreEight 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
... Show MoreSeventy of Klebsiella pneumoniae isolates had been collected from some Hospitals in Baghdad city from October to December 2017. The 70 isolates were taken from diverse clinical specimens. All K. pneumoniae isolates were identified based on API 20 E and Vitek2 compact system. Antibiotics sensitivity test was carried out toward 10 antibiotics using discs diffusion method. The level of antibiotics resistance was 81.42% for Ceftriaxone, whereas the low level of antibiotics resistance was 37.14% for Piperacillin. K. pneumoniae isolates were typed genotypically by using two different methods of amplification, multiplex-PCR and enterobacterial repetitive intergenic consensus (ERIC)-PCR typing methods. Results showed that out of 70 isolates, there
... Show MoreNormally, bacteria exposed to antibiotics at sub minimal inhibitory concentrations (MIC) inside the host. Therefore, the current study aimed to comprehend the association among hemolysins, biofilm, as well as gentamicin resistance in local MRSA isolates. Around 35 Staphylococcus aureus locally isolated from different clinical specimens were employed in this study. Methicillin resistance was detected via cefoxitin disk diffusion and mecA amplification methods. MIC of gentamicin was estimated by broth microdilution method. Hemolysin genes involving hla, hlb, hld, and hlg were determined using multiplex polymerase chain reaction (PCR) technique. Microtiter plate method was employed for biofilm assessment
... Show MoreNormally, bacteria exposed to antibiotics at sub minimal inhibitory concentrations (MIC) inside the host. Therefore, the current study aimed to comprehend the association among hemolysins, biofilm, as well as gentamicin resistance in local MRSA isolates. Around 35 Staphylococcus aureus locally isolated from different clinical specimens were employed in this study. Methicillin resistance was detected via cefoxitin disk diffusion and mecA amplification methods. MIC of gentamicin was estimated by broth microdilution method. Hemolysin genes involving hla, hlb, hld, and hlg were determined using multiplex polymerase chain reaction (PCR) technique. Microtiter plate method was employed for biofilm assessment in the presence and absence of gentamic
... Show MoreThe 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 MoreObjective: The present work was undertaken to investigate the impact of sub inhibitory concentration of gentamicin on hla gene expression in methicillin resistant Staphylococcus aureus isolates. Methods: The bacterial isolates used in this study represent 33 MRSA strains, previously isolated form patients visiting several hospitals in Baghdad. Gentamicin, vancomycin, and oxacillin MIC were determined using broth dilution method. Microtiter plate method was adopted to investigate the biofilm forming capacity. Alpha hemolysin was detected by culturing MRSA isolates on rabbit blood agar. Furthermore, hla gene was detected in MRSA isolates using conventional PCR technique; while, qRT-PCR method was performed to assay the hla expression in plank
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