An elevated mutation frequency favors development of vancomycin resistance in Staphylococcus aureus.
نویسندگان
چکیده
The emergence of intermediate vancomycin resistance, mainly in methicillin-resistant Staphylococcus aureus strains, has become a great concern. Thorough characterization of clinical and laboratory vancomycin-intermediately resistant S. aureus (VISA) strains identified multiple, resistance-associated changes most probably due to stepwise mutations. We hypothesized that an elevated mutation frequency as found, e.g., in mutator strains defective in DNA mismatch repair could allow rapid acquisition of adaptive mutations in the presence of vancomycin. We therefore subjected S. aureus RN4220 and its isogenic mutator strain, the mutS-knockout mutant RN4220DeltamutS, to a stepwise vancomycin selection procedure. Vancomycin resistance evolved much more quickly in the mutator background than in the wild type (5 versus 19 passages, respectively). In addition, a higher resistance level could be reached (MIC, 32 versus 4 micro g/ml, respectively). The susceptibility to other antibiotics with the exception of teicoplanin remained unchanged. Concomitantly with increasing vancomycin resistance, a loss of phage typeability and differences in growth behavior as well as an improved ability to regrow at high vancomycin concentrations were observed. In conclusion, an elevated mutation rate in S. aureus led to the rapid development of vancomycin resistance, indicating that a high mutation frequency could be one of the factors that favor the emergence of vancomycin resistance in S. aureus.
منابع مشابه
Antibiotic resistance and typing of agr locus in Staphylococcus aureus isolated from clinical samples in Sanandaj, Western Iran
Objective(s): Infections by Staphylococcus aureus remain an important health problem. The aims were to detect mecA, staphylococcal cassette chromosome mec (SCCmec), accessory gene regulator (agr), and integrons in S. aureus and to investigate the relationship of agr types with antibiotic resistance of isolates. Materials and Methods: In this cross-sectional study, 70 S. aureus isolates w...
متن کاملVancomycin Resistance Pattern of Staphylococcus Aureus among Clinical Samples
Abstract Background and Objective: Vancomycin is used for treatment of methicillin-resistant S. Aureus (MRSA) infections therefore, resistance to this antibiotic is increasing. We aimed to determine the antibiotic resistance pattern and frequency of vancomycin resistant S. Areas (VRSA) strains isolated from clinical samples. Material and Methods: In this cross-sectional study, 100 S. Aureus iso...
متن کاملPrevalence of Vancomycin Resistance in Methicillin-Resistant Staphylococcus Aureus
Background & Aims: Staphylococcus aureus is one of the most common pathogens in nosocomial infections. Vancomycin is the most important therapeutic drug of choice for treatment of infections caused by methicillin-resistant Staphylococcus aureus (MRSA) strains. Therefore, vancomycin-resistant Staphylococcus aureus (VRSA) or vancomycin-intermediate Staphylococcus aureus (VISA) strains are warning...
متن کاملPCR-mediated identification of Methicillin and Vancomycin resistant genes in Staphylococcus aureus strains isolated from the nasal cavity
Staphylococcus aureus is colonized in the human nasal cavity and would contaminate hospital and therapeutic environments. This bacterium has a genetic diversity in terms of resistance to antimicrobial agents. Therefore, the purpose of this study was identificatied of Methicillin and Vancomycin resistant genes in Staphylococcus aureus strains which has been isolated from the nasal cavity. 189 pa...
متن کاملذخیره در منابع من
با ذخیره ی این منبع در منابع من، دسترسی به آن را برای استفاده های بعدی آسان تر کنید
برای دانلود متن کامل این مقاله و بیش از 32 میلیون مقاله دیگر ابتدا ثبت نام کنید
ثبت ناماگر عضو سایت هستید لطفا وارد حساب کاربری خود شوید
ورودعنوان ژورنال:
- Antimicrobial agents and chemotherapy
دوره 46 11 شماره
صفحات -
تاریخ انتشار 2002