جستجوی مقالات مرتبط با کلیدواژه « استافیلوکوکوس » در نشریات گروه « پزشکی »

Staphylococcus aureus has been recognized as a powerful pathogen that causes numerous infections. Today, S.aureus has acquired multiple resistances to a wide range of antibiotics, including beta-lactams. Beta-lactamases hydrolyze beta-lactam antibiotics and are expressed through activation of the blaZ gene. The aim of this study was to evaluate the frequency of blaZ gene in clinical isolates of S.aureus isolated from Hamadan hospitals.

In this descriptive cross-sectional study, all S.aureus strains were randomly selected and transferred to the laboratory. In clinical isolates confirmed by biochemical tests of genomic DNA extraction procedures using Synagen Cat extraction kit. No.PR881614) was performed according to the manufacturerchr('39')s protocol and 1% agarose gel was used to view the PCR product. Data were analyzed by SPSS software.

The results of this study showed that 32 patients (64%) and 18 women (36%) were isolated from S.aureus hospitalized in Fatemieh and Sina hospitals. The pattern of antibiotic resistance obtained was that penicillin (10 µg) with 100% resistance and cefazolin (30 µg) with 5% resistance had the highest and lowest resistance, respectively. Also 94% of isolates were resistant to cefoxitin (30 µg) and 90% of isolates were resistant to oxacillin (1 µg). Of 50 S.aureus isolated from clinical isolates, 44 contained the blaZ beta-lactamase gene.

Based on the findings of this study, isolates isolated from clinical specimens showed the same pattern of abundance. Therefore, it is likely that more or more drug resistance will be transmitted to hospitals.

Staphylococcus aureus is an important microorganism that causes the development of various diseases in humans by secretion of factors that are known as supra-antigen of staphylococci. Enterotoxin B of Staphylococcus aureus is a bacterial antigen responsible for food poisoning in humans. To produce the corresponding polyclonal antibody, an antigen is injected into a susceptible animal and the serum of antibody content is extracted. Bacterial superantigens are potent T cell activators that can have acute or chronic effects on the central nervous system. This study aimed to develop a mouse polyclonal antibody against enterotoxin B of Staphylococcus aureus.

The Bradford method was used to determine protein concentration. For evaluation and identification of the antigen, the samples were transferred onto a nitrocellulose membrane by SDS-PAEG gel and analyzed by western blot analysis. Mice immunization was performed at intervals of zero, two, and four weeks using intraperitoneal injection. Antibody titer was measured in antisera isolated from the animal by the ELISA method.

Different concentrations of protein (0-32 μg) with different adsorption were calculated with the formula y = 0.0279x + 0.1222. There was no excess protein in the acrylamide gel. In the western blot analysis, the resulting bands represent complete conformance with the standard sample and are free from any unwanted protein. The results of the ELISA test were significant for the secretion of the second time at p <0.05. In the double diffusion test, there was a bond between the control and the antigen.

Prepared toxoid has completely lost its fecundity and therefore could be used to immunize and produce polyclonal antibodies against enterotoxin B of Staphylococci.

Biosurfactants are compounds that are produced by different microorganisms and have an emulsifying property. This study aimed to investigate extractive biosurfactant from bacillus subtilis (PTCC1720) against the biofilms of Staphylococcus aureus (PTCC 1112), Staphylococcus saprophyticus (PTCC 1440) and Staphylococcus epidermidis (PTCC 1435). This study was conducted in vitro to examine the effect of biosurfactant produced by Bacillus subtilis in prevention of biofilm formation and removal of biofilms produced by different staphylococcal species. First, bacillus subtilis was cultured in suitable culture media for producing biosurfactant. Then, extraction of produced biosurfactant was done and anti-biofilm properties were assessed by determination of optical density at 570 nm by ELISA reader equipment. Statistical analysis was performed by SPSS software version 16 and ANOVA. The means were compared at 95% confidence level by Duncan's method. According to the results, the biosurfactant produced by bacillus subtilis had emulsification index equal to 40% and oil replacement area was 1.8 ± 0.3 cm-2. Produced biosurfactant by bacillus subtilis had a significant effect on preventing microbial formation with the highest effect on biofilm of staphylococcus aureus and Staphylococcus saprophyticus. Also, the results showed that the biofilm of staphylococcus epidermidis had the highest resistance in this respect. According to this study, the antibiofilm activity of biosurfactant extracted from Bacillus subtilis against the biofilm of staphylococcus aureus, epidermidis and saprophyticus was shown. In addition, this type of biosurfactant can be effective in removing biofilms formed by staphylococcal strains.

Biosurfactants are amphiphilic molecules produced by microorganisms that due to  surfactant activity, have several applications in different industries such as cleaning, emulsification, foaming and dispersion. The aim of this study was to investigate the effect of biosurfactant extracted from saccharomycess cerevisiae on biofilm formation of staphylococcus aureus (PTCC 1112), staphylococcus saprophyticus (PTCC 1440) and staphylococcus epidermidis (PTCC 1435). The effect of this biosurfactant on the removal of the mentioned bacteria’s biofilms was also assessed. In this laboratory study, after Saccharomycess cerevisiae cultivation for producing biosurfactant  and extraction of the produced biosurfactant , the effect of the extracted biosurfactant in preventing the formation of biofilms of staphylococcus aureus, staphylococcus saprophyticus and staphylococcus epidermidis was assessed using  96-well polystyrene microplate and absorbance reader at 570nm by ELISA reader. The same method was used for determining the ability of biosurfectant in removal of biofilms. Statistical analysis was performed by ANOVA. The means of treatments were compared with Duncan's method at a confidence level of 99%. The results showed that biosurfactant of saccharomycess cerevisiae had an emulsification index equal to 55%. The biosurfactant activity was determined via  the oil displacement method and the area of displaced oil was 2.5±0.5 cm2. The results showed  the biosurfactant produced by saccharomycess cerevisiae had the most effect on preventing biofilm formation by staphylococcus aureus and staphylococcus saprophyticus. Biosurfactant caused the all tested bacteria’s biofilms to be removed.  Biosurfactant produced by saccharomycess cerevisiae has strong  anti-biofilm activity against biofilms of Staphylococcus aureus, epidermidis and saprophyticus.

The biofilm of bacteria, especially pathogenic bacteria, endanger food safety due to their high resistance to disinfectants; use of herbal extracts, essential oils and hydrocele during extraction of essential oils is one of the ways to combat the resistance microbial biofilms. Therefore, the effect of hydrocele extracted from turmeric (Curcuma longa) and cinnamon (Cinnamomum verum) on staphylococcal biofilm was investigated in this study.

In this experimental study, the hydrocele of turmeric and cinnamon was extracted using steam distillation method. After isolation of essential oil, 10, 30 and 50% concentrations were used to investigate the anti-biofilm effects. Anti-biofilm effect against Staphylococcus aureus (PTCC 1112), Staphylococcus saprophyticus (PTCC 1440) and Staphylococcus epidermidis (PTCC 1435) was evaluated using ELISA reader. The efficacy of both hydroceles in removing bacterial biofilms formed on different surfaces (glass, steel and polyvinyl chloride) was determined by microbiological culture method.

The results showed that optical density in control samples of Staphylococcus aureus, epidermidis and saprophyticus was 0.254±0.03, 0.138±0.019, and 0.146±0.017, respectively, but after exposure to 50% cinnamon hydrocele reached 0.072±0.011, 0.096±0.021, and 0.064±0.01, and after exposure to 50% turmeric hydrocele reached 0.074±0.02, 0.098±0.021, and 0.057±0.011, respectively. Investigation of the efficiency of hydrocele in removal of formed biofilms showed that the highest decrease was in the case of Staphylococcus saprophyticus biofilm formed on glass and steel surfaces, and the logarithm of bacterial population declined from 4 to 1 in the presence of 50% hydrocele (p ≤ 0.05).

The results of this study showed that the hydrocele extracted from cinnamon and turmeric is effective in preventing biofilm formation of staphylococcal bacteria and eliminating the formed biofilm.

Plant extracts and essential oils are commonly used in traditional and industrial doogh products to inhibit bacterial activities. In this study, the antibacterial effects of the essential oils of Olivera decumbens and Nepeta binaludensis against Staphylococcus aureus and Escherichia coli in doogh were investigated. Essential oils of Olivera decumbens and Nepeta binaludensis were collected from Binalud and Pol-Dokhtar respectively and the essential oil of these species were extracted by the hydro-distillation method. Then, different concentrations of essential oils (12.5, 50, 100 and 200 μl mL-1) were added to doogh containing 104 Staphylococcus aureus and Escherichia coli bacteria. Finally, the bacteria were counted during 5 days of storage. The results showed that, at the maximum duration of 5 days storage, the difference between the inhibitory activity of Oliveria decumbens and Nepeta binaludensis essential oils at concentrations of 50 and 100 μl mL-1 respectively against Escherichia coli and Staphylococcus aureus in comparison with control sample was significant (P < 0.05). Moreover, it was observed that the antibacterial effect of Oliveria decumbens was higher than Nepeta binaludensis due to its more phenolic compounds. The results of the present study have shown that essential oils of Oliveria decumbens and Nepeta binaludensis have good inhibitory effects against Staphylococcus aureus and Escherichia coli in doogh. So they can be used as preservatives in traditional and industrial doogh products.

Staphylococci are considered as one of the most important etiological agents of omphalitis. Due to the importance of early diagnosis of omphalitis in newborns, this infection can be diagnosed by novel techniques such as multiplex PCR which is rapid, cost- effective and more accurate than microbial culture. The aim of this study was to determine the frequency of Staphylococcus aureus, S. epidermidis and S.hominis species in umbilical cord infection in newborns. In the present study, 45 umbilical cord samples were collected from Shahid Afzali pour hospital in Kerman, Iran. Followed by DNA extraction, Multiplex PCR reactions were performed using specific 16srDNA primers for S. aureus, S. epidermidis and S.hominis. Finally, PCR products were analyzed using electrophoresis and sequencing. Also, microbiological and biochemical differentiation tests were performed for the diagnosis of Staphylococci on all specimens. Amplification of 16srRNA genes for S. aureus, S. epidermidis, and S. hominis using Multiplex PCR demonstrated that the frequency of S. epidermidis ,S. aureus and S.hominis were 4.4%, 6.6% and 2.2% in the studied samples, respectively. The prevalence of staphylococcal isolates using differential tests was shown to be 33.3%. This study indicated that, Multiplex PCR is a proper method for simultaneous identification of S. aureus, S. epidermidis and S.hominis species. Also, Staphylococci can be considered as a significant cause of umbilical cord infection in newborns. However, further studies urgently are needed to confirm this finding.

Indoor air environments contain a wide variety of microorganisms such as bacteria, fungi, and viruses in which some of them can affect the human health. Filtration is considered as one of the most common methods to remove microorganisms in these environments. The purpose of current study was to investigation the neat and photocatalytic HEPA filters performance at different face velocities and various intensity of UVC light source on the reduction of airborne microorganisms. Material and Method: After installation of the neat and photocatalytic HEPA filters in a closed–loop chamber, suspension of Staphylococcus epidermidis and Bacillus subtilis bacteria with a concentration of 107 CFU / ml were sprayed into the closed–loop chamber by nebulizer. Sampling of penetrated microorganisms from filters were performed using the NIOSH 0800 method under ambient temperature 22±3oC, relative humidity 35±5%, and different air velocity (0.1 m/s and 0.3 m/s) and UVC different radiation intensity (1 mW/cm2, 1.8 mW/cm2 and no radiation (dark)) at 30 minutes time period. penetrated microorganisms density from filters was determined in term of CFU/m3. There were no significant differences in the penetration rates of microorganisms at the dark mode between the two neat and photocatalytic HEPA filters (p>0.05). The penetration rate of bacteria was significantly decreased in the neat and photocatalytic HEPA filters at UVC radiation mode with various intensities than dark mode (p<0.05). In addition, comparison of the filters in the illuminance modes of 1 mW/cm2 and 1.8 mW/cm2 were statistically significant (P <0.05). Also, UVC radiation with the 1.8mW/cm2 illuminance compared to the 1 mW/cm2 illuminance resulted in a greater reduction in the bacterial penetration from both types of filters, which is statistically significant(p<0.05). The bacteria penetration rate dramatically increased by increasing the face velocity from 0.1 m/s to 0.3 m/s under UVC radiation at an illuminance of 1mW/cm2, 1.8mW/cm2 and as well as in no radiation mode in both types of HEPA filters (P <0.05). Photocatalytic HEPA filters and increasing UVC illuminance, especially at lower surface velocities, have a significant positive effect on reducing airborne microorganisms and increasing the efficiency of HEPA filters

Backgrounds and Juice drinks have high nutritional value, antioxidants, vitamins and minerals which are widely consumed due to therapeutic properties. The aim of this study was to survey the bacteriological quality of juices in Shahrood city.
This descriptive cross-sectional study was done in the spring and summer seasons of 2014-2015, on juices sold in the Shahrood city study. A self-report questionnaire confirmed by the ministry of health, with certain modifications (as needed), was applied to determine the bacteriological quality of juices and the relationship between food safety knowledge and practices of vendors. In this study, all juice shops (9 units) were considered and the research was carried out by visiting and completing the questionnaires. In order to determine the bacteriological quality of fruit juices, sampling was done from juice shops. The samples the assessed for the presence of Staphylococcus, E. coli, total coliform, yeast and mold counts by using standard methods. The results were compared with the standards of the Institute of Standards and Industrial Research of Iran. Then, obtained data were analyzed by Excel and SPSS software.
About 16.12 % of the samples contaminated to Staphylococcus aureus, 22.58% to Escherichia coli, 12.9% to total coliform, 38.7% to yeast and 9.67% to mold. Also, a significant correlation between parameters such as level of literacy (Education) of vendors, amount of sales, site and refrigerator hygiene, personal hygiene, food hygiene, and sanitation was existed (P ≤ 0.001).
The results showed that all biological parameters were higher than the standard level, which was due to the lack of principles and rules of personal hygiene, food hygiene and sanitation. Hence, management, monitoring and purposeful education was much more needed for food safety supervision and training to prevent contamination of food with pathogenic agents, and greater emphasis on compliance with regulations is Article 13.

Staphylococcus aureus is the second cause of hospital acquired infections, and responsible for 80% of purulent infections, and majority of skin infections. About 30 to 50 percent of normal people carry staph in their nose or groin and armpits. VanA, VanB, VanC1, VanC2/C3, VanG, VanL, and VanX are genes responsible for encoding resistance to vancomycin, TychoPlanyn and Avoparcyn, among them vanBand vanAare the most common cause of resistance that could be located on a plasmid or a chromosome and can be transferred via conjugation. The aim of this study was to The aim of this study was to investigatethe role of VanA and VanB genes in Cefoxitin resistant Staphylococci aureuscausing skin infections in patients admitted to Razi Hospital in Tehran using real time PCR method.
The samples were collected from Khordad 1394 for one year in the Microbiology Department of the Clinical Laboratory of Razi Hospital. Exudative skin lesions were sampled by sterile swab and cultured on the blood agar and EMB medium. Then catalase, oxidase and coagulase tests were performed on the gram-positive cocci and the sensitivity to vancomycinin Cefoxitin-resistant Staphylococcus aureus was determined using the E-test method. The presence of vanAand vanBgenes were investigated by Real Time PCR.
Out of 978 patients with infected skin lesions, 733 samples of Staphylococcus aureus were isolated. Of these, 124 were Cefoxitin resistant, among them 8 samples had a high response rate of 3, and 5had high response above 16. But VanA and VanB genes were not responsible for resistance in any of them.
Due to the development of resistant strains of Staphylococcus in skin and hospital infections, identification of its encoding genes are necessary in order to use appropriate antibiotics to reduce the course of treatment and the side effects of taking antibiotics.

Infections caused by Staphylococcus species associated with biofilm are considered as a serious clinical concern in medical devices used patients with serious clinical illness and are usually possible source of nosocomial infections. The polysaccharide adhesion mechanism encoded by the ica operon generate a direct role in biofilm formation and infection of the bacteria. In this study, the presence of ica operon were studied in clinical isolates of S. aureus and S. epidermidis in relation to the biofilm formation.
In this study, the 27 S. aureus isolates and 73 S. epidermidis isolates were identified by conventional biochemical methods.
The ability to biofilm formation was evaluated by colony morphology on Congo red agar (CRA) and test tube. Presence of the ica genes was detected by PCR method.
In this study, from 27 S. aureus isolates and 73 S. epidermidis, 25 and 70 isolates had the ability to form biofilms respectively. The results showed that 93% and 96% of the S. aureus isolates and S. epidermidis isolates had the potential to form biofilm respectively. Genetic analysis showed that icaRADBC operon was present in 4 and 11% of S. aureus isolates and S. epidermidis isolates respectively. The S. epidermidis isolates were more frequently positive for icaA, icaB and icaC than S. aureus while the most prevalent gene was icaD found in 30% of the S. aureus isolates.
The results obtained showed that in consistent with other researches; biofilm formation in Staphylococcal isolates was not associated with present of ica operon and presumably depend on several factors.

Background and L-asparaginase is a well-known enzyme that is used as one of the most effective anti-leukemic drugs. Considering that the asparaginases used as antitumor are bacterial-based enzymes, the aim of this study was to find indigenous potential bacteria producing asparaginase. The enzyme producing bacteria was isolated from the agricultural soils around Gharchak, Tehran province, Iran. Screenings were performed on nutrient agar and M9 agar, respectively. The most efficient bacterium having asparaginase activity was selected and identified by biochemical and phylogenetic methods. Asparaginase activity was assayed by Nesslerization method. Optimization of the enzyme production was conducted by assessment of some factors such as the effect of carbon and nitrogen sources, salt concentration, pH, temperature and agitation. The selected bacterium was identified as a strain of staphylococcus that was named MGM1.The optimal conditions for enzyme activity was obtained at following conditions: 1% glucose as carbon source and 0.5 g/l beef extract as nitrogen source, without salt (NaCl) at pH range of 7-8 with shaking 120 rpm at 35 ◦C. The optimal activity for the enzyme produced by MGM1 was similar to physiological conditions of human body, therefore, further studies on this enzyme would be of great value in finding a new efficient asparginase enzyme.

“Mahyaveh” is a traditional fish sauce that is produced by the fermentation process in Iran. As the microorganisms can grow in fermentation process, safety assurance of this Iranian food condiment is very important. Mahyaveh is produced from Sardinella sp. Fish and the viable cell numbers of total bacteria, halophilic bacteria, fungi, halophilic yeasts and lactic acid bacteria from 7 homemade samples were counted. Test of gram coloration, catalase, oxidase, fermentation of carbohydrate, phosphate, coagulase, nitrate reduction, production of acid and CO2, beside morphological study, used for recognition of the bacteria. The viable cell numbers of total bacteria in the first week of production were determined to be in the range of 8.7±102 CFU/g and after 2 month it reached to 7.2±102 CFU/g. Bacillus subtilis and Bacillus licheniformis showed significant difference by the other bacillus sp. (P<0.05). Lactobacillus plantarum and Lactobacillus alimentaria consist 59.9% of total lactic acid bacteria. Micrococcus sp. and Staphylococcus sp. constitute the 70% of the total bacterial community. Micrococcus luteus showed the significant difference by the other species of the micrococcus (P<0.05). Staphylococcus lentus had the highest community in the staphylococcus sp. (P<0.05). Candida sp., Saccharomycopsis sp., Pichia sp., and Mucor was recognized as yeast. High concentration of pathogenic bacteria, coliforms and spore producing bacteria were not recognized in the Mahyaveh and the safety of the Mahyaveh could be confirmed but additional study is essential.

Urinary tract infection is one of the most common bacterial infections and coagulase negative staphylococci are a common cause of this disease based on some reports. Due to increasing the resistance resulting from antibiotics consumption, this study was performed to determine the antibiotic resistance pattern of the coagulase negative staphylococci isolated from urinary tract infections in Gonabad, Iran.

This cross-sectional study was performed on 264 coagulase negative staphylococci isolated from patients who were referred to Jahad Daneshgahi Laboratory due to urinary tract infection in Gonabad city. Identification of bacterial strain was performed by classical identification methods and antimicrobial susceptibility testing was carried out on Mueller-Hinton agar (merck-Germany) using disk diffusion (Kirby Bauer›s) technique.

Out of 264 isolates, the most frequent species of coagulase negative staphylococci (CNS) isolates were Staphylococci epidermidis (84%) followed by Staphylococcus saprophyticus (14%). Based on antibiotic resistance pattern,››Penicillin›› (56.43%) showed the highest resistance followed by "erythromycin" (46.21%), and "nitrofurantion" (42.42%) in order. However, CNS showed the highest susceptibility to "ciprofloxacin" (82.57%), "vancomycin" (78.03%) and "Amikacin" (74.24%).

The findings showed that the use of ciprofloxacin and vancomycin, as the first choice in empirical treatment of Urinary Tract Infection (UTI) in the region, should be reconsidered.

Poor oral hygiene in elderly people increases the colonization of opportunistic pathogens such as Candida and Staphylococci. The presence of yeasts and bacteria in the oral cavity of elderly people can be harmful and in certain conditions may cause oral and systemic infections. The general purpose of this study was to determine the oral health status, particularly the prevalence of Candida and Staphylococcus species in the oral cavity of elderly people in Yazd. Oral Saliva was aseptically collected from seventytwo elderly individuals and cultured on selective fungal and bacterial media. The density of isolated microorganisms Such as Candida and Staphylococcus species was determined base on colony forming units (CFU) and identified through the biochemical and microbiological tests. Fifty- eight percent of Candida species isolated from 50 (69.4%) of the subjects were Candida albicans. 70.8 percentage of Staphylococcus species isolated from 65 (90.3%) of elderly are Coagulase negative. The Candida colonization in denture users is significantly higher than the elderly without denture (p= 0.001). C. albicans and the Coagulase negative staphylococcus are the most prevalent microorganisms isolated from elderly oral cavity in this study. The elderly have a higher risk of opportunistic bacterial and fungal infections. Their oral health care should be improved to protect them from opportunistic infections.

Staphylococcus aureus (S. aureus) is an important pathogen and is one of the most common infectious agents in hospitals. S. arerus induces serious complications in hospitalized patients. Medical staffs are the main source of infection in hospital and transmit this organism to patients. Thus a study on prevalence of S. aureus carriage among health care personnel may provide a valuable information for infection control programs. This is a descriptive cross-sectional study. The study included 240 hospital personnel. The specimens were obtained with swabs from the anterior nares or nasopharynx, the ecological niches of S. aureus, and cultured according standard guidelines. MRSA strains detection was achieved with disk diffusion method. Antibiotic susceptibility of S. aureus strains was determined with disk diffusion method according to the recommendations of the producer (PadtanTeb Company). The results showed that the prevalence of nasal pharyngeal and nasopharyngeal carriage among the attending staff were 22.5, 6.3 and 2.9 respectively. While 82 % of the S. aureus were MRSA. There was a significant difference between the prevalence of among the personnel working in the orthopedic's ward, operating room and the rest of the staff in other departmens (p < 0.05). All MRSA strains were susceptible to vancomycin. No significant differences were found between resistant to methicillin and host factors such as sex, age and duration of occupation. In conclusion with regarding to the high prevalence of carriage state in hospital staff, identification, treatment and eradication of S. aureus can prevent transmission this organism to patients and provide a good measure to control nosocomial staphylococcal infection in hospitalized patient.

Fluorescent in situ hybridization (FISH) is a new diagnostic technique for specific detection of microorganisms at molecular level and direct visualization of microbial morphology. In this study, FISH technique was evaluated for detection of staphylococci. A set of 16S rRNA-targeted oligonucleotide probes were used for FISH. For detection of Staphylococcus aureus in sputum samples by FISH and comparison with conventional bacterial culture, 76 sputum samples were investigated. According to our data, sensitivity and specificity of FISH for detection of this bacterium were 86.7% and 100%, respectively. As another part of this study, 41 blood culture specimens were examined for detection of staphylococci. In compare with conventional culture methods, sensitivity and specificity of FISH for detection of S. aureus were 100% and for non S. aureus species of staphylococci, sensitivity and specificity of FISH were 95.7% and 100% respectively. All steps of FISH technique were performed within 3h. Therefore, FISH is a rapid, sensitive, and specific technique for detection of staphylococci.