Microbiology
Pegah Kananizadeh; Solmaz Ohadian Moghadam; Yasaman Sadeghi; Abbas Rahimi Foroushani; Hossein Adibi; Mohammad Reza Pourmand
Abstract
Background & Objective: Diabetic foot ulcer (DFU), is one of the most frequent causes for hospitalizations in patients with diabetes. A major problem in the treatment of DFU is the increased-incidence of methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to determine the ...
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Background & Objective: Diabetic foot ulcer (DFU), is one of the most frequent causes for hospitalizations in patients with diabetes. A major problem in the treatment of DFU is the increased-incidence of methicillin-resistant Staphylococcus aureus (MRSA). The aim of this study was to determine the SCCmec types of MRSA isolates and their epidemiology among patients with diabetes. Methods: This study was carried out on 145 diabetic patients with DFUs. The antibiotic susceptibility tests (ASTs) were performed using the disk diffusion method and E-test technique. SCCmec typing was done by multiplex PCR. Moreover, the presence of virulence toxin genes, including pvl and lukED was detected by PCR assay. Result: In 145 samples from which S. aureus was predominantly isolated, 19.48% were MRSA. Analysis of MRSA isolates revealed that the most prevalent SCCmec type was type IV (46.7%) followed by type III (30.0%) and type V (20.0%). One strain (3.3%) was untypeable. The prevalence of pvl and lukED was 56.7% and 100%, respectively. Conclusion: The high prevalence of MRSA in DFUs represents the high levels of antibiotic usage among patients with diabetes. In this study, resistance to other important clinical antibiotics was detected among MRSA isolates. The high proportion of SCCmec type IV and V strains, even in former hospitalized patients, indicates the entrance of these clones to the clinical setting.
Mohammad Rahbar; Somayeh Karami; Jalil Vand Yousefi
Volume 6, Issue 1 , January 2011, , Pages 27-31
Abstract
BackgroundandObjectives:RapidandaccuratedetectionofmethicillinresistantStaphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The aim of this study was to compare conventional methods against the E-test minimum inhibitory concentration ...
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BackgroundandObjectives:RapidandaccuratedetectionofmethicillinresistantStaphylococcus aureus (MRSA) is an important role of clinical microbiology laboratories to avoid treatment failure. The aim of this study was to compare conventional methods against the E-test minimum inhibitory concentration (MIC) method to determine the best phenotypic method.
Materials and Methods: Methicillin resistance was studied among clinical isolates of S. aureus from April to October 2009 in Milad Hospital of Tehran. These methods included E-test MIC, oxacillin screen agar, oacillin disk diffusion, cefoxitin disk diffusion, and CHROMagar- MRSA methods.
Results: Out of 294 isolates of S. aureus, one hundred and six (36%) strains of MRSA were isolated from clinical specimen. Oxacillin screen agar and CHROMagar-MRSA showed both 110 MRSA isolates. The sensitivity and specificity for these two methods were 100% and 97.9%, respectively. The sensitivity and specificity of oxacillin disk diffusion method was similar to those of oxacillin screen and CHROMagar-MRSA. One hundred and eight strains of S. aureus were MRSA by cefoxitin disk diffusion method. The sensitivity and specificity of cefoxitin disk diffusion method was 100% and 98.1% respectively. All isolates including MRSA were susceptible to vancomycin. Nearly al MRSA isolates were resistant to erythromycin, clindamycin, chloramphenicol, tetracycline, ceftriaxone and ciprofloxacin.
Conclusion: All phenotypic methods had high sensitivity and specificity for detection of MRSA. However, cefoxtin disk diffusion method in comparison to other methods had higher specificity.
Mohammad Rahbar; Nooshafarin Safadel
Volume 1, Issue 4 , September 2006, , Pages 145-148
Abstract
Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Detection of MRSA in laboratories is very important for treatment and appropriate infection control. The aim of this study was to evaluate cefoxitin disk diffusion ...
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Background and Objectives: Methicillin-resistant Staphylococcus aureus (MRSA) is a major cause of nosocomial and community acquired infections. Detection of MRSA in laboratories is very important for treatment and appropriate infection control. The aim of this study was to evaluate cefoxitin disk diffusion method for detection of MRSA and comparison of this method with other conventional methods. Methods: A total of 175 clinical isolates of S. aureus isolated from clinical specimens were studied. The isolates were identified by conventional laboratory methods. In this respect, E-test MIC, cefoxitin and oxacillin disk diffusion methods, and MAST ID Methicillin strips were used for detection of MRSA. All disk diffusion methods were performed as recommended by NCCL and manufacturers’ guidelines. Results: Using E-test MIC, 53 out of 175 strains of S. aureus were resistant to methicillin. In addition, disk diffusion method using oxacillin disk showed that 52 strains are resistant to methicillin. In this respect, 8 strains had intermediate resistance to methicillin. For cefoxitin disk diffusion method, 52 strains were resistant to methicillin. This method had a good correlation with E-test MIC method. Meanwhile, MAST ID methicillin strips detected 47 strains that were resistant to mehicillin. Sensitivity and specificity for both cefoxitin and oxacillin disk diffusion methods were 98%and 100% respectively. However cefoxitin was better than oxacillin for detecting intermediate resistant strains of S. aureus. Sensitivity and specificity for MAST ID methicillin strips were 91% and 100% respectively. Conclusion: This study revealed that cefoxitin disk diffusion method is a good alternative for oxacillin disk diffusion method for detection of MRSA. This method is more reliable for identification of intermediate resistant strains of S. aureus.
