Showing 7 results for Methicillin
Mohammad Reza Nafisi, Huriyeh Kalhor, Behzad Zamanzad, Ali Karimi, Efat Farokhi, Majid Validi,
Volume 11, Issue 2 (6-2008)
Abstract
Introduction: Methicillin resistant staphylococcus aureus strains are the most important agents of nosocomial infections. The conventional antibiotic susceptibility methods such as disk diffusion are not suitable for detection of these strains due to their heteroresistancy. Therefore, in this study, agar screen and duplex-PCR were compared in determination of methicillin resistant Staphylococcus aureus (MRSA) strains isolated from nose of personnel in Hajar hospital of Shahre-kord, 2007. Materials and Methods: In this experimental study a total of 204 nasal swabs from personnel of Hajar hospital over a period of 6 months were collected. The specimens were cultured on mannitol salt agar for primary isolation and identification of Staphylococcus aureus strains and their susceptibility pattern to oxacillin was assessed using agar screen method. Finally, using duplex PCR, the isolates were tested for the presence of mecA gene. Results were compared and sensitivity and specificity of the method was determined. Results: In this study, 23 of the 52 (44%) Staphylococcus aureus isolates were resistant to oxacillin using agar screen method. However, mecA gene was detected in 27 of the 52 strains (52%). Our results showed that the sensitivity and specificity of agar screen method in determination of MRSA strains were 81.5% and 96%, respectively comparing with PCR. Conclusion: Oxacillin agar screen, comparing PCR, is an inexpensive, applied and phenotypical method with low false positive and suitable for screening of MRSA. However, due to its relatively high false negative results is not appropriate for screening of MRSA strains isolated from hospital-employed nasal carriers.
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.
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.
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.
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.
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.
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.
