ABSTRACT
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 warnings for the medical community. The aim of this study was to evaluate the prevalence of vancomycin resistance in methicillin-resistant Staphylococcus aureus isolated from the nose of patients hospitalized in Imam Reza Hospital, Kermanshah, Iran. In the present study, 85 strains of methicillin-resistant Staphylococcus aureus were isolated from patients in Imam Reza Hospital and evaluated for vancomycin resistance with microdilution test, Epsilometer test [E-test], and polymerase chain reaction [PCR]. None of the strains were completely resistant to vancomycin; however, 39 strains [45.9%] were diagnosed as hetero-VRSA [hVISA] strains. VISA and VRSA strains were not observed in this study which is a promising finding in the treatment of clinical infections due to Staphylococcus aureus in our society. However, in our study, the prevalence of hVISA strain was 45.9%, which is perhaps a sign of the appearance of more resistant strains [VISA and VRSA] in our country in the future
ABSTRACT
Antibiotics such as fluoroquinolones are used for treating infections caused by Gram-negative bacteria, including Acinetobacter baumannii strains some time have extended-spectrum beta-lactamase [ESBL], but ESBL production is rather rare. Resistance to fluoroquinolones antibiotics is mediated by lactamases and other mechanisms of resistance. The aim of the present study was to investigate of the prevalence of ESBL production and clonal relatedness of A. baumannii in Iran. A. baumannii isolates identified from patients at hospitals in Kermanshah, Iran, were studied. The double disk method was used for detection of ESBL production. The susceptibility to different antibiotics was determined by the disk diffusion method [CLSI]. Clonal relatedness was determined by pulsed-field gel electrophoresis [PFGE] and processed by Bionumerics 7.0 software. Statistical analyses were performed using SPSS-16.0. This study showed high prevalence of resistance to ampicillin and cefpodoxim [98.1 and 92.3%]. Fifty-two of the 84 isolates were identified as ESBL producers. Only colistin and tigecycline remained active against all isolates tested. The PFGE identified eight distinct pulsotypes: A [N=9], B [N=10], C [N=2], D [N=5], E [N=9], F [N=15], G [N=1] and H [N=1]. The PFGE profiles A, B and F were believed to be endemic [specially clone F that was dominant across different wards of the hospitals and appeared to be endemic] in the ICU, emergency, pediatric and infection area throughout the years. Early and timely detection of ESBL-producing A. baumannii clones is useful for preventing their spread within the hospital. PFGE analysis is helpful for detection of common strains in different wards and prevention of further spread of these pulsotypes to other hospital environment