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 expression of pslA and fnbA genes of both species was investigated using RT-PCR. This work indicated that starvation stress significantly increased the biofilm biomass and bacterial density in all mono and mixed biofilm-producing strains. Interestingly, co-culture biofilms exhibited higher resistance to starvation as compared to monoculture. The current results also showed that the expression of fnbA and pslA genes was up-regulated under starvation stress in mono-and coculture biofilm. meanwhile, up-regulates of both genes in co-culture biofilm was significantly higher than mono- species biofilm.
Susceptibility of thirty seven clinical isolates of Staphylococcus aureus to various antibiotics was tested. 100 % of tested isolates were resistant to ampicillin, while the lowest resistance recorded to amikacin 8.10 %. Four of S. aureus isolates showed resistant to vancomycin. Minimum inhibitory concentration (MIC) of isolates 33 and 56 for vancomycin was ≥ 32 μg/ml.
Methicillin resistant Staphylococcus aureus (MRSA) is the most common pathogenic bacteria in the hospitals and communities, the ability to form biofilm is considered the main cause of Staphylococcus pathogenicity since it provides resistance to both antibiotics and host immune response, so this study was aimed to evaluate the biofilms formation and its association with antibiotic resistance in clinical isolates of MRSA, in order to achieve this aim, 237 samples were collected from different patients with wounds infections after surgeries and samples from operations galleries from varies hospitals in Baghdad ,68 isolates out of 237 were subjected to Staphylococcus aureus according to conventional meth
... Show MoreA local isolate Bacillus subtilis was used, which producing
thennophilic complex enzyme having similar activity of endogluganase
enzyme ( Endo-l,4-B-Dglucanase ).
Partially digested chromosomal DNA of Bacillus subtilis by Eco
Rl restriction enzyme randomly cloned into Eco Rl pSU10l shuttle vector. The resulted hybrid plasmid was transformed into protoplast of
Streptomyces sp. SH-H.
The result revealed  
... Show MorePseudomonas aeruginosa gram-negative, bacilli and facultative aerobic, P. aeruginosa cause cystic fibrosis patients, wounds, burns, and immunodeficienct patients, that have many virulence factors such as pyocyanin , cytotoxic ,biofilm formation and motility, Eighty-eight isolates belonging to P. aeruginosa were collected including the 66 clinical isolates obtained from different hospitals in Baghdad and were from different sources and 22 environmental isolates from previous studies of soil near oil fields. Microscopical and cultural characteristics were studied and diagnosed using biochemical tests, VITEC device, their ability to adhere to non-living (Polystyrene), living cell line (A549) and cytotoxicity of bacterial filtrate
... Show MoreThis study aimed to detect of contamination of milk and local soft cheese with Staphylococcus aureus and their enterotoxins with attempt to detect the enterotoxin genes in some isolates of this bacteria. A total of 120 samples, 76 of raw milk and 44 of soft cheese were collected from different markets of Baghdad city. Enterotoxins in these samples were detected by VIDAS Set 2 system and it was found that enterotoxin A is present in a rate of 44.74% in milk samples and in a rate 54.50% in cheese samples. While other enterotoxins B, C, D, E were not found in any rate in any samples.
Through the study 60 isolates obtained from milk and cheeses were identified as Staphylococcus aureus by cultural, morphological and biochemical test by u
In humans, Pseudomonas aeruginosa is the second most frequent gram negative nosocomial pathogen in hospitals and has the highest case-fatality rate of all hospital-acquired bacteremia because of the hardy resistance of these bacteria to mechanical cleansing as well as to disinfectant, and many antibiotics. The susceptibility of bacteria against the antibiotics is modulated by several local factors such as temperature which modified drug efficacy, so this study was carried out to evaluate the effect of different temperature (20,42,45)Ċon the susceptibility of Pseudomonas aeruginosa to the minimum inhibitory concentrations (MIC) of the antimicrobial agents before and after irradiation. The samples collected from 150 persons suffering from
... Show MoreOne hundred thirty seven Staphylococcus spp. isolates were isolated form one hundred fifty clinical specimens which were collected from several hospitals at Al-Sulaimaniya city. Seventy two Staphylococcus aureus isolates, 28 Staphylococcus epidermidis isolates and 37 isolates related to other coagulase negative staphylocci (S. chromogenes, S. lugdunensis, S. cohnii, S. saprophyticus, S. hominis, and S. haemolyticus constituted 3.60%, 2.20%, 2.90%, 2.90%, 6.60%, and 8.80%, respectively). Burn specimens represented the highest (P< 0.05) reservoir for S. aureus and S. epidermidis isolates. Staphylococci developed variable susceptibility to 4 antibiotics (cefoxitin; 30 μg, oxacillin; 1μg, methicillin; 5μg, and cefotaxime; 30 μg). Neve
... Show MoreTen isolates belong to the Staphylococcus bacteria from different clinical swabs were taken from patients in Ibn al-Nafis Hospital and Central Public Health laboratory, according to many morphological and biochemical tests that used to identify bacterial species S. aureus, the results showed that 8 isolates when investigated their ability to produce a slime layer using Congo red agar method the results showed that SA5 isolate was the best compared to other isolates through change the color of colonies to the pink and Congo red agar -colored Black.
When examining the inhibitory effect of grapefruit extracts in the growth of isolated bacteria SA5 S.aureus, results showed that the aqueous extract of the seeds at different concentrations
Pseudomonas aeruginosa was isolated from various clinical samples included urine, sputum, stool, ear, wound & burn swabs. Detection of the ability of local isolates to produce staphylolysin enzyme was studied, on Tryptic soya agar + 0.2% (wt./vol.) of heat killed Staphylococcus. aureus at temperature 100oC. medium and the diameters of lysis zone ranged from 5-22mm, then the isolate P16 was chosen to extract staphylolysin A (LasA) and its specific activity reaches 8.59 unit /mg protein, whi1e the isolate P5 was chosen to extract staphylolysin D (LasD) where it's specific activity reaches 0.66 unit /mg protein since the two isolates were the most production of enzyme. Staphylolysin enzyme was extracted by cooling centrifugation and par
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