The pathogenicity resulting from Staphylococcus aureus infection has remarkable importance as one of the community-associated bacterial infections, due to the virulent ability of these bacteria to produce biofilms. This study was designed to detect biofilm production in clinical isolates from samples of wounds and urinary tract infections. The expression levels of the icaA gene that is responsible of slime layer production in biofilms was compared in isolates with different biofilm producing capabilities. Fifty seven samples that included 32 samples from urine and 25 samples from wounds were collected from Alwasti Hospital, Al-Kindi Teaching Hospital, and Alzahraa Clinic, Baghdad, Iraq. The bacteria was identified according to biochemical tests, API20 strip test, and PCR assay. The results of 16S rRNA PCR detection revealed that nine isolates were identified as S. aureus. The biofilm assay showed that 46.15% of the isolates were strong biofilm producers, 46.15% had moderate ability to produce biofilm, and 7.70% were weak producers. Quantitative PCR assay was carried out on three isolates with different biofilm-producing abilities. The results demonstrated that the strong biofilm-producing isolates had significantly higher (P ≤0.01) gene expression level (6.508) compared with the moderate (1.624) and the weak (1.231) isolates.
The gene expression of the most important structural genes ica A and D of biofilm, sarA, and sigB regulatory genes of some methicillin-resistant Staphylococcus aureus (MRSA) isolates were examined using the real-time polymerase chain reaction after 24 hours of growth. The results revealed that the isolates with strong biofilm production had the highest gene expression of the structural icaA and D genes. Whereas the isolates that showed moderate and weak biofilm production, recorded the lowest gene expression. The results of the regulatory genes sarA, and sigB fluctuated among all MRSA isolates. Isolate No. 64 recorded the highest gene expression
... 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
... Show MoreIn accordance with epidemic COVID-19, the elevated infection rates, disinfectant overuse and antibiotic misuse what led to immune suppression in most of the population in addition to genotypic and phenotypic alterations in the microorganisms, so a great need to reevaluate the genetic determinants that responsible for bacterial community (biofilm) has been raised. A total of 250 clinical specimens were obtained from patients in Baghdad hospitals and streaked on Mannitol salt agar medium. The results revealed that 156 isolates appeared as round yellow colonies, indicating that they were mostly identified as Staphylococcus aureus from 250 specimens. The antibiotic resistance pattern of the isolates for methicillin 37.17% (n=58), Amoxic
... Show MoreThe current study aimed to detect the effect of gentamicin stress on the expression of hla (encodes hemolysin) and nuc (encodes nuclease) genes of Staphylococcus aureus. Fifty-eight isolates identified as S. aureus were isolated locally from different clinical specimens. Disk diffusion method was used to detect the resistance to S. aureus. The minimum inhibitory concentration (MIC) of gentamicin was estimated by broth microdilution method. hla and nuc genes were determined by polymerase chain reaction technique. The biofilm was evaluated using the microtiter plate method in the presence and absence of gentamicin at sub-MIC. The results showed that 18
... Show MoreAtotal of 75 different clinical samples were collected from different hospitals in Baghdad Biochemical and morphological characterization tests showed that forty isolates were identified as Staphylococcus aureus Antibiotic susceptibility tests of all isolates towards ten antibiotics were carried out and results showed that many isolates (97.5 %) were resistant to ?-lactam antibiotic , 70 % were resistant to Tetracyclinee , 62.5% were resistant to co-trimoxazole , 60 % were resistant to ciprofloxacin , 55% were resistant both of chloramphenicol and erythromycin , 52.5% were resistant to gentamicin , 35% were resistant to rifampicin , 10% were resistant to vancomycin . According to the above results the S.aureus I1 which is isolated
... 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 MoreThree 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,
... Show MoreThis 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 MorePvcABCD are cluster of genes found in Pseudomonas aeruginosa. The research was designed to examine the relationship between the pvc genes expression and cupB gene, which plays a crucial role in the development of biofilm, and rhlR, which regulates the expression of biofilm-related genes, and to investigate whether the pvc genes form one or two operons. The aims were achieved by employing qRT-PCR technique to measure the gene expression of genes of interest. It was found that out of 25 clinical isolates, 21 isolates were qualified as P.aeruginosa. Amongst, 18(85.7%) were evaluated as biofilm producers, 10 (47.6%), 5 (23.8%), and 3 (14.2%) were evaluated as strong, moderate and weak producers respectively, while, 3 (14.2%) were considered
... Show MoreThe current study aimed to detect the effect of gentamicin stress on the expression of hla (encodes hemolysin) and nuc (encodes nuclease) genes of Staphylococcus aureus. Fifty-eight isolates identified as S. aureus were isolated locally from different clinical specimens. Disk diffusion method was used to detect the resistance to S. aureus. The minimum inhibitory concentration (MIC) of gentamicin was estimated by broth microdilution method. hla and nuc genes were determined by polymerase chain reaction technique. The biofilm was evaluated using the microtiter plate method in the presence and absence of gentamicin at sub-MIC. The results showed that 18 (31%) and 40 (69%) S. aureus isolates were sensitive and resistant to gentamicin, respectiv
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