Showing 14 results for Staphylococcus Aureus
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.
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.
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
1 and sul1 in isolates were determined by PCR method.
Results: The highest antibiotic resistances rate in isolates was found for clindamycin.
All of the isolates were susceptibel to vancomycin. 80% of MRSA and 40% of the MSSA isolates carried class 1 integrons, whereas class 2 integron were found in 12 % and 4% of MRSA and MSSA isolates, respectively. Also, all isolates that were class 1 integron gene positive contain qacE1 and sul1 genes. Class 3 integrons were not found.
Conclusion: The high frequency of class 1 integron in MRSA and MSSA isolates associated with high rate of antibiotic resistance indicating that may be integrons play an important role facilitating the spread of antimicrobial resistance in this region. Clinical doctors and infection control committee should take this issue seriously.
Hamid Motamedi, Shahnaz Dehbashi, Hamed Tahmasebi, Mohammad Reza Arabestani,
Volume 21, Issue 5 (10-2018)
Abstract
Background and Aim: Staphylococcus aureus(S.aureus) has many pathogens. Antibiotic resistance may increase the invasion of this bacterium. The aim of this study was to determine the role and effect of some antibiotic resistance in the spread of pathogenic strains of S.aureus in different clinical specimens.
Materials and Methods: 95 clinical isolates of S.aureus were collected from different clinical specimens. Antibiotic resistance pattern was determined by Disc diffusion method (Kirby-Bauer) for 6 different classes. Identification of adhesion agent genes in isolated isolates was performed using Multiplex-PCR and specific primers. For analysis of the results, GraphPad Prism version 6 and ꭕ2 statistical sampling was used. p≤0.05 was considered significant.
Findings: Of 95 isolates of S.aureus, 29 isolates (30.52%) were resistant to methicillin, 12 isolates (12.63%), resistant to clindamycin, 48 isolates (50.52%), resistant to gatyfloxacin, 88 (92.63%) isolates resistant to gentamicin, 57 (60%) isolates resistant to erythromycin and 79 isolates (83.15%) were resistant to tetracycline. fnbA genes were isolated in 14 isolates (14.73%), fnbB in 29 isolates (30.52%), fib in 21 isolates (22.10%), clfA in 17 isolates (17.89%) and clfB in 19 isolates (20%). There was a significant correlation between resistance to macular antibiotics, tetracycline, beta-lactam, lacosamide, aminoglycoside and pathogens.
Conclusion: The adhesion factors in S.aureus possibly cause some structural changes and cause resistance to various antibiotic classes.
Hamed Tahmasebi, Sanaz Dehbashi, Mohammad Reza Arabestani,
Volume 21, Issue 7 (2-2019)
Abstract
Background and Aim: Gene mutation in Staphylococcus aureus is one of the most important causes of antibiotic-resistant strains. The High Resolution Melting Curve (HRM) analysis of DNA method can detect these mutations very high quality. The purpose of this study was to evaluate the role of clinical sample type in the occurrence of nucleotide mutations in the mecA gene of S. aureus by HRM method.
Materials and Methods: In this experimental study, 43 clinical isolates of S. aureus were used. To detect possible mutations, isolates with mecA gene were replicated and sequenced. Then, analysis was performed using StepOne Software v2.3 and HRM v3.0.1 software. Sequencing results were used as gold-standard.
Ethical Considerations: This study with research ethics code IR.UMSHA.REC.1396.637 has been approved by research ethics committee at Hamadan University of Medical Sciences.
Findings: Of 43 clinical isolates of S. aureus, 11 isolates (25.58%) had mecA gene and 32 isolates (47.41%) lacked the mecA gene. According to different clinical samples, 3 isolates (27.27%) were resistant to methicillin from blood samples, 2 isolates (18.18%) from urine specimens, 2 isolates (18.18%) from wound samples, 2 isolates (18.18%) of the catheter samples, 1 isolate (9.09%) of the abscess and 1 isolate (9.09%) were separated from the nose swab. In the meanwhile, isolates from the wound and urine had the highest mutation in the adenine amino acid as A → T, A → G, A → C, and
A → X. Isolates taken from blood have mutations in Guanine amino acid as
G → A.
Conclusion: There was a significant relationship between type of mutation and type of clinical specimen in methicillin-resistant Staphylococcus aureus isolates.
Elham Pishgar, Milad Makhfian,
Volume 22, Issue 2 (6-2019)
Abstract
Background and Aim: A variety of bacteria like Staphylococcus aureus utilize quorum sensing to perform their important activities such as biofilm formation and production of virulence factors. Interfering with the bacterial QS will disable the bacteria to perform above-mentioned vital activities. The principal aim of the study was to evaluate the effects of five plant extracts against bacterial Quorum sensing of Staphylococcus aureus.
Materials and Methods: Thirteen strains of Staphylococcus aureus were isolated from patients with dental implant infection and identified. The plant species were collected from vicinity gardens of Fars Province and extracted using 96% ethanol. The anti-QS and antimicrobial susceptibility methods were then carried out to evaluate their bactericidal and QS properties with the use of Agrobacterium tumefaciens NTL/PZLR4. Furthermore, the biofilm production of the isolates was evaluated by microtiter plate (MTP) assay.
Ethical Considerations: This study with research ethics codes 01-16-1-1959 and 73/118248 has been approved by research ethics committee at Islamic Azad University, Jahrom and research sciences branch, respectively.
Findings: The results of the study disclosed that the extract of raspberry blossom possesses significantly (p<0.05) anti-QS property (>21 mm). The anti-QS activity was proved by creating clear halo sides of the wells formed by Agrobacterium tumefaciens NTL/PZLR4. Moreover, the extracts of tarragon, wheat flower, flixweed and basil showed antimicrobial properties.
Conclusion: According to the anti-biofilm and anti-QS properties of raspberry blossom extract against the isolates of Staphylococcus aureus, it could be considered as a mouthwash against dental bacterial infection with the identification of active compounds in the raspberry.
Ramin Parvizrad, Sara Khalili Dermani, Azam Ahmadi,
Volume 23, Issue 3 (8-2020)
Abstract
Background and Aim: Staphylococcus aureus is common pathogens of nosocomial infections. Nasal swabs in hospital staff is main sources of hospital infections are considered. The aim of this study was to determine the frequency of nasopharyngeal carriers of methicillin-resistant Staphylococcus aureus and microbial contamination of health care workers' cell phones in Emergency department of Vali-e-Asr Hospital in Arak City.
Methods & Materials: In this descriptive study, nose swabs and cell phone levels were taken from 70 health care workers in the emergency ward of Vali-e-Asr Hospital. The Staphylococcus aureus clinical isolates were identified using standard microbiological methods (catalase, coagulase, mannitol fermentation and DNase). The susceptibility to oxacillin and cefoxitin was detected by the disk diffusion and the mecA genes in this clinically isolated strain of staphylococci was investigated by Polymerase Chain Reaction (PCR).
Ethical Considerations: This study was approved by the Research Ethics committee of Arak University of Medical Sciences. (Code : IR.ARAKMU.REC.1396.282).
Results: According the results, Staphylococcus aureus was isolated in 16 cases, which 5 cases were methicillin-sensitive S. aureus (MSSA), and 11 cases were Methicillin resistant S. aureus (MRSA). Also, 3 cell phones were infected with Staphylococcus aureus, which 1 case was MRSA and 2 cases were MSSA.
Conclusion: The results of this study showed that frequency of MSSA strains is significant in emergency personnel of the hospital. Thus, regarding to the risk of epidemics due to nosocomial infections, periodic testing for the identification and treatment of carriers among employees for controlling and preventing hospital infections seems necessary.
