Showing 17 results for Staphylococcus
Mahboobeh Naderi Nasab, Parisa Fateh Manesh, Bahar Shahnavazi,
Volume 6, Issue 4 (12-2003)
Abstract
Introduction: In the 1950s vancomycin was introduced as an effective antibiotic for curing infections caused by methicillin resistant Staphylococcus aureus. Three decade after using vancomycin, resistant coagulase negative staphylococcus to this antibiotic was reported. In this study, we evaluate the Staphylococcus aurous resistant to vancomycin.
Materials and methods: During this invesitigatin which lasted for 6 months, 50 Staphylococcus aurous samples were taken from burn wards of each of two Imam-Reza and Gaem hospitals, Mashhad. All selected samples were resistant to methicillin and their MIC to vancomycin was determined.
Results: Of 50 separated bacteria from Imam-Reza and Gaem hospitals subjects, 4 patients had MIC equal to 12.5 mg/ml. In isolated samples from Gaem hospital, one case has MIC equal to 12.5 mg/ml.
Conclusion: With respect to expanding the resistant toward vancomycin, thus it is recommended to inhibit the resistance of this organism in the wards.
Hosein Sarmadian, Farshideh Didgar, Hamid Abtahi,
Volume 11, Issue 1 (3-2008)
Abstract
Introduction: Staphylococcus Aureus is one of the most important pathogenes in human. Regarding the ability of this bacterium in nasal colonization, carriers can increase the incidence of many nosocomial infections. This study was designed to compare the efficacy of two antimicrobial regimens (topical nasal Mupirocin and oral Ciprofloxacin) in treatment of Staphylococcus Aureus carriers and its recurrence. Materials and Methods: This study is a triple blind clinical trial that was performed on 366 cases of Vali-e-asr hospital personnel. Nasal cultures were prepared from all these cases. Among them, 45 cases were carriers which were divided in two groups (A and B). Group A were treated by single dose of oral Ciprofloxacin (1500 mg) and Vit A+D ointment as placebo for 5 days (twice a day) and group B were treated by single dose of oral placebo and nasal Mupirocin ointmdent for 5 days (twice a day). After this period, nasal cultures were repeated in the two groups to evaluate the efficacy of treatment. Also after 5 weeks the last cultures were performed in order to determine the prevalence of reinfection. Results were analyzed using Chi-square test. Results: Results showed that, 12.9% of Vali-e-asr hospital personnels were nasal carriers of Staphylococcus Aureus. Also the efficacy of topical nasal Mupirocin regimen (89.5%) was significantly higher than single dose of oral Ciprofloxacin regimen (55%) (p=0.019). But there was no significant difference between prevalence of reinfection in topical (13.3%) and oral regiment (20%). Conclusion: According to the present data, it seems that topical Mupirocin therapy is more effective than single dose of oral Ciprofloxacin in treating Staphylococcus Aureus carriers. However there is no significant difference in the prevalence of reinfection between the two methods.
Pedrama Ariapanah, Morteza Sattari, Zahra Jafari-Azar, Adonis Poormohammadi Mojaveri,
Volume 13, Issue 4 (1-2011)
Abstract
Background: Due to problems caused by traditional dressings, scientists have long been in search for producing alternative cellulose. Unique characteristics of bacterial cellulose synthesized by acetobacter xylinum, due to its nanostructure cellulose, resulted in attempts to devise an ideal dressing with this cellulose. The main aim of this study is to evaluate the effect of impregnated bacterial cellulose on staphylococcus aureus culture. Materials and Methods: In this descriptive-analytical study, cellulose disks synthesized by bacterial cellulose and cellulose blank disks (without antibiotic) were placed in 3.3% ciprofloxacin hydrochloride. These disks were, then, together with ciprofloxacin standard, control cellulose, and cellulose blank disks, placed on the cultured media of staphylococcus aureus. After 24 hours, the results were obtained through the measurement of growth inhibition zone. Determining the amount of antibiotic absorbed into bacterial cellulose can be done through the comparison of the effects of cellulose disks containing different concentrations of ciprofloxacin hydrochloride and ciprofloxacin standard disks. Results: Both cellulose and blank disks created a growth inhibition zone in staphylococcus aureus media, whereas the growth inhibition zone of cellulose and cellulose blank disks (negative control) were insignificant. Conclusion: Noticing the unique characteristics of bacterial cellulose as a dressing and its proven ability in absorption and release of ciprofloxacin hydrochloride, the prospects are seen for production of antibiotics containing dressings of this microbial product in future.
Mohammadbagher Salehi, Mojtaba Saadati, Babak Barati, Mahdi Saberi, Gholamreza Olaad, Aliasghar Rahimi,
Volume 14, Issue 6 (1-2012)
Abstract
Background: The major aim of this study was synthesis and assay of antimicrobial activity of peptide D28 and its new analogues derivatives as dimeric peptides.
Materials and Methods: Three antimicrobial peptides known as D28, Di-D28-Lys,Di-Cys-D28 including 20, 41, 42 residues were synthesized respectively. For peptide synthesis, solid phase peptide synthesis method using blocked amino acids with flourenyl methoxy carbonyl group and for peptide purification HPLC were used. Peptides compositions were confirmed by amino acid analysis and SDS-PAGE electrophoresis. Antimicrobial tests against Staphylococcus aureus and Pseudomonas aeruginosa were performed as disk and well diffusion on plate and by adding to liquid broth culture (Broth macrodilution) in different concentrations.
Results: Three required peptides (D28, Di-D28-Lys, Di-Cys-D28) successfully were synthesized. All three peptides were effective against S. aureus, but Di-Cys-D28 on the contrary to two other ones, showed no antimicrobial activity against P. aeruginosa. The inhibitory activity of Di-D28-Lys against P. aeruginosa was more than that of D28 peptide.
Conclusion: Improvement of antimicrobial peptides activity through dimerization depends on the methods of dimerization and the strain of bacterium. Di-D28-Lys peptide in comparison with D28 and Di-Cys-D28 showed wide range and more antimicrobial activity. Therefore, Di-D28-Lys peptide could be a suitable antibiotic candidate for future studies.
Mohsen Rezazadeh, Rasoul Yousefi Mashouf, Hossein Sarmadyan, Ehsanollah Ghaznavi-Rad,
Volume 16, Issue 2 (5-2013)
Abstract
Background: Staphylococcus aureus is considered a common pathogenic factor in infections. Increase in infections caused by this bacterium in developing countries has led to many problems. The aim of this study is to identify the antibiotic patterns of methicillin-resistant Staphylococcus aureus isolated from patients in the central hospital of Arak.
Materials and Methods: In this descriptive cross-sectional study, a total of 100 samples were isolated from hospital patients during one year. The isolates sensitivity to cefoxitin and oxacilin disks were evaluated through disk diffusion. Using polymerase chain reaction (PCR), the isolates were tested for the presence of mecA gene. Finally, antibacterial resistance patterns of the isolates to 13 antibiotics were determined.
Results: In this study, 80 samples in a total of 100 isolates of Staphylococcus aureus were methicillin-resistant. Evaluation and assessment of antibiotic resistance showed the greatest resistance to penicillin (100%), tetracycline (88.50%), levofloxacin (85.70%), and ciprofloxacin (85.70%), respectively, while the lowest levels of resistance were observed to antibiotics chloramphenicol (5.70%), netilmicin (5.70%), and mupirocin (0%), respectively.
Conclusion: This study showed increased resistance to different antibiotics in Staphylococcus aureus that is a serious warning to the treatment of infections caused by this bacterium in the region. Therefore, in order to prevent increased resistance to other antibiotics, it is essential to withhold prescriptions and unessential use of available antibiotics.
Maryam Sadrnia, Mohammad Arjomandzadegan,
Volume 17, Issue 6 (9-2014)
Abstract
Background: Nowadays, with the development of drug resistance, the use of herbs as an alternative to chemical drugs is considered by researchers. In this work, effects of Aloe vera extracts on clinical isolates was studied.
Materials and Methods: Aloe vera plant medicinal plants were obtained from a greenhouse. Three extracts including essential oils, extracts and no essential oils and essential oil extraction method also includes a complete extract of Aloe vera were prepared Percolation total. To investigate Microbiology extracts of two strains of Staphylococcus aureus and Staphylococcus epidermidis clinical strain of Gram-positive and Gram-negative isolates of Klebsiella pneumoniae and Escherichia coli strains Staphylococcus aureus ATCC25923 were used as well. Evaluate the effect of two methods: Kirby-Bauer disk with the minimum inhibitory concentration (MIC) was performed using microplate dilution. Turbidity was determined by an ELISA reader apparatus.
Results: All extracts of aloe vera on Klebsiella with a diameter of 32±2 mm mg/ml 285.7 concentration with microplate dilution method was 2.23 mg/ml. Staphylococcus aureus and MIC zone diameter of 30±2 mm and mg/ml 2.23, Staphylococcus epidermidis and Escherichia coli mg/ml4.46 mm 17.85 mm 30±5 mg/ml 17.85 respectively. Similar concentration of 17.85 mg ml Aloe Vera with a circle formed by the disk mc/ml 10 gentamicin was shown. This effect is similar to other bacteria antibiotics gentamicin, clindamycin, erythromycin, and Cefixime compared with Aloe Vera extract has been proven. Essential oils made from all parts of the same whole extract of aloe vera, but not essential extracts, bacteria studied were ineffective.
Conclusion: In this study the effects of similarity and some excess water Asrsarh Aloe Vera with common antibiotics on bacteria causing the infection was confirmed. Therefore, by production of appropriate pharmaceutical plant drugs with fewer side effects, bacterial infections couled be treated properly.
Meysam Hasan Nejad Bibalan, Ezzatollah Ghaemi, Fateme Shakeri, Naeme Javid,
Volume 17, Issue 6 (9-2014)
Abstract
Background: Staphylococcus aureus is a gram-positive bacterium that has remained a persistent pathogen, causing infections such as endocarditis and toxic shock syndrome in humans. The accessory gene regulator (agr) system of Staphylococcus aureus is responsible for controlling the expression of many genes that code virulence factors and hemolysis.This study was carried out to determine the S.aureus agr group based on their source of isolation and any relation between agr specificity groups, pigmentation and hemolysis .
Materials and Methods: DNA of 194 S. aureus isolates were extracted by lysozym-phenol chloroform method, included 85clinical samples, 58 samples which isolated from nose of health care workers and 51 cases obtained from food product in Gorgan, North of Iran. PCR-based assays were used to evaluate agr locus nucleotide polymorphism for the identification of agr specificity group. Pigmentation on nutrient agar medium and hemolysis on sheep Blood agar medium were assessed.
Results: The majority of isolates belonged to agr group I (43.3%), followed by agr group III (28.87%), agr group II (22.68%), and agr group IV (5.15%). The isolates belonged to agr group IV have greater ability to produce hemolysin (60%) whereas isolates belonged to agr group III have greater ability to produce pigment (60.5%).
Conclusion: agr group I was predominant among health care worker and food product specimens in Gorgan, North of Iran but in strains isolated from patient, agr group III was predominant. Investigation of the possible role of agr group III in Staphylococcus aureus infection in the next studies is recommended.
Mahboobeh Bahroodi, Gholamreza Irajian, Mohammad Mehdi Fizabadi, Bahador Behrouz, Saeed Bahroudi, Mehdi Mahdavi,
Volume 17, Issue 11 (2-2015)
Abstract
Background: The emergence of antibiotic resistance, particularly resistance to methicillin in Staphylococcus aureus has made the treatment process more difficult. Therefore, producing of an effective vaccine seems to be necessary to prevent infections with methicillin-resistant Staphylococcus aureus (MRSA). In this study, a mixture of naloxone and alum has been used to improve the efficacy of a vaccine against MRSA.
Materials and Methods: MRSA 834 strain was grown on TSB medium and the grown cells were harvested and killed by sonication and were used as a vaccine model. Balb/c mice were divided into six groups and the vaccines were either injected alone, with naloxone, alum, or a mixture of naloxone - alum and control group received naloxone and PBS buffer. Total IgG antibody level was measured by ELISA method and finally, the challenge test of this bacterium was performed and the mice were examined regarding the degree of bacteria growth in their kidneys.
Results: The serum level of Total IgG antibody in the mixture of naloxone – alum with MRSA group was shown to be significantly increased (p<0.05). Furthermore, the lowest bacterial load was observed in this group.
Conclusion: It seems that a mixture of naloxone and alum as an adjuvant with the killed methicillin-resistant Staphylococcus aureus enhances the humoral immunity leading to a high level of protection against MRSA infections. Therefore, this seems to be a good option for improving the performance of this vaccine.
Safiyeh Abbasi, Behnam Zamanzad,
Volume 18, Issue 6 (9-2015)
Abstract
Background: Colonization with MRSA is no longer limited to hospitalized patients or persons with predisposing risk factors and at present there are several strains of community-acquired MRSA (CA-MRSA). The purpose of this study is to determine etA and etB genes in isolated Staphylococcus aureus strains of clinical samples from teaching hospital in Shahrekord in 2014.
Materials and Methods: In this descriptive study, 220 clinical samples were collected from teaching hospitals in Shahrekord. The microbiologic characteristics of isolates were determined using microbiologyic standard methods. The MRSA detection was carried out on oxacillin agar medium. The detection of virulence genes etA and etB was used by PCR. Inducible resistance to clindamycin was tested by "D-test".
Results: In 220 isolates, 110 detected as S. aureus and 13 as MRSA. Inducible clindamycin resistance was seen in 4 (3.5%) of the isolates. The frequency of genes etA, etB in studied strains was 7.6 and 15.3, respectively. Also, Inducible resistance to clindamycin was seen in four isolates(2%).
Conclusion: The results of this study confirme the presence of community- acquired strains in Shahrekord. The results of this study indicate the presence of genes etA and etB in the strains studied, transforming into the strains of Staphylococcus aureus resistant to methicillin obtained from hospital, the development and transfering these strains in the community.
Mohammad Reza Arabestani, Mohammad Abdoli Kahrizi,
Volume 18, Issue 11 (2-2016)
Abstract
Background: Agr systems, is responsible for control and coordination in production of virulence factors, exotoxins secretory and hemolysins in Staphylococcus aureus. The aim of this study was to determine and identify the frequency of agr genes in susceptible and methicillin-resistant Staphylococcus aureus strains in clinical samples and carriers employed in remedial centers.
Materials and Methods: This descriptive study was done among a total of 200 strains of Staphylococcus aureus isolated from clinical samples and healthy carriers in Hamadan. Antibiotic susceptibility pattern of all isolates was determined by disk diffusion methods. After DNA extraction, the presence of mecA and agr genes was investigated using PCR. SPSS software package version 20 was used to perform statistical tests.
Results: All 200 Staphylococcus aureus strains were susceprible to vancomycin. The prevalence of mecA was 50%. The PCR results showed that agrA was the most perevalent gene followed by the agrC in all isotated Staphylococcus aureus strains. None of the isolates harbored the agrB and agrD gene.
Conclusion: Pathogenesis of Staphylococcus is dependent on some proteins other superficial or excreted which under controlling of agr system. In the present study, the feequency of agrA gene in the methicillin-resistant strains, methicillin-sensitive strains isolated from clinical samples and carriers employed in remedial centers was higher than the other agr types. Therefore, presumably, agrA gene plays an important role Staphylococcal infections.
Fahimeh Nourbakhsh, Hassan Momtaz,
Volume 19, Issue 4 (7-2016)
Abstract
Background: Biofilm formation is one of the pathogenicity factors of Staphylococcus aureus that can help the bacteria to stick to the other surface and also increase antibiotic resistance pattern. This study aimed to investigate the phenotypic and genotypic indices for formating biofilm in Staphylococcus aureus isolates isolated from infectous samples.
Materials and Methods: 250 Staphylococcus aureus strains isolated from hospital infections were selected. Antibiotic resistance pattern was determined by using disk diffusion method. The ability of biofilm formation was investigated by molecular and phenotypic method.
Results: In this study, 73.5% of isolates were able to bind strongly, 5.33% had the ability of medium connection and 15.4% had the ability of weak connection in biofilm production. The frequency of icaC and icaB genes were 67.3% and 63.2%, respectively. 92.2% of biofilm producing isolates have mecA gene.
Conclusion: The spread of antibiotic resistance in isolates especially isolates that produce biofilm will create serious problems in the hospital therapeutic wards.
Mohsen Golnari Maranni, Mohammad Rabbani Khourasgani, Mohammad Ali Asadollahi, Rasoul Shafiei,
Volume 19, Issue 11 (2-2017)
Abstract
Abstract
Background: Prevalence extension of antibiotic resistant bacteria has raised concerns about control of infections especially nosocomial infections. Many attempts have been done to replace antibiotics or limit their use. The use of antimicrobial agents produced by bacteria as antibiotic replacement has been promising in recent years. The goal of this study was to isolate Bacillus strains and evaluate their antimicrobial activity against some standard pathogens and clinical antibiotic resistant strains.
Materials and Methods: In the present study, Bacillus strains were isolated from various resources and identified by 16S rDNA PCR method. Then, the phylogenetic tree of the isolates was constructed and antimicrobial activity of the isolates was investigated against some standard pathogens and clinical antibiotic resistant strains using spotting and well diffusion methods.
Results: Eight Bacillus strains were isolated from 15 different samples. Based on the molecular identification, the isolates were identified as B.pumilus, B.coagulans, B.licheniformis, B.endophitycus and B.amiloliquefaciens. The results showed that isolates have antimicrobial activity against meticilin-resistant Staphylococcus aureus, vancomycin resistant enterococci, Klebsiella, Acinetobacter, Salmonella, Shigella, Listeria, Streptococcus and Escherichia coli.
Conclusion: In this study, isolated Bacillus strains produced antimicrobial agents against pathogens and antibiotic resistant strains and inhibited their growth.
Somayyeh Moatti, Behrouz Shojaee Sadi, Ehsanollah Ghaznavi-Rad,
Volume 20, Issue 7 (10-2017)
Abstract
Abstract
Background: Integrons are mobile genetic elements that play an important role in dissemination of antibiotic resistance genes. The aim of present study is to determine the antibiotic resistance profile, frequency of integrons genes (class 1, 2, 3) and compare it between MRSA and MSSA isolates from clinical infections.
Materials and Methods: 50 MRSA and 50 MSSA isolates from March to September 2015 were isolated from infection site of hospitalized patients referred to Valiasr hospital Arak, Iran were subjected to this study. All isolates were tested for susceptibility to antibiotics using disk diffusion method. Then, the mecA gene was studied to validate resistance. The frequency of integrons (class 1, 2, 3) and the variable region genes like qacE