The frequency of vanB and vanA genes in Vancomycin Resistant Staphylococcus aureus isolates obtained from dialysis patients

BACKGROUND AND OBJECTIVES Hemodialysis is the most common method of alternative treatment in kidney patients. In these patients, due to weak immune system and continuous use of venous catheter for dialysis, the possibility of hospital infection is high. The most common cause of infection in these patients is Staphylococcus aureus bacteria. Vancomycin is now identified as a last resort for the infection control. The aim of this study is to investigate the prevalence of resistance to methicillin and vancomycin in Staphylococcus(S.) aureus isolates collected from dialysis patients of Imam Reza Hospital in Tabriz, IranMATERIALS AND METHODS Swab Samples were obtained from nasal, throat and catheter of ۲۳۰ dialysis patient at Imam Reza Hospital in Tabriz, Iran. the isolation of S. aureus bacteria was performed by conventional microbiological methods. Antibiotic sensitivity patterns of isolates were determined by disk diffusion method and E-test. The frequency of Van A, Van B and mecA genes was detected by PCR reaction.RESULTS AND DISCUSSION Among the ۱۷۰ S. aureus isolates collected from hemodialysis patients in this investigation, the highest resistance was observed to Ampicillin (۷۹.۴۱%), while the highest sensitivity was observed against Rifampin (۸۲.۹۴%). For the detection of vancomycin resistant isolates, E- test was performed for ۳۵ isolates that was found as vancomycin resistant isolates based on disk diffusion results. The results showed that ۳۷.۱۴% of the samples were resistant, ۱۴.۲۸% were sensitive, and ۲۰% showed intermediate resistance to vancomycin. According to the PCR results, ۲۹.۴۱% of patients were positive for mecA gene, ۵.۲۹% for the vanA gene, and ۷.۰۵% were positive for the vanB gene. All the isolates carrying vanA and vanB were resistant to Ampicillin (۷.۰۵%), Cefoxitin (۵.۲۹%), Erythromycin (۴.۷۰%), Methicillin (۳.۵۲%), and Oxacillin (۳.۵۲%). The number of female patients carrying the vancomycin-resistant gene was higher than the number of men(p<۰.۰۵). Based on results, there is a significant relationship between diabetes and high blood pressure prevalence and resistance to methicillin and vancomycin.Conclusion Because of the increasing prevalence of resistance to methicillin and vancomycin, it is necessary to propose an appropriate antibiotic pattern to halter resistant infections in patients with weak immune system like hemodialysis patients.

کلیدواژه ها:

Dialysis Patients ، S. aureus ، Vancomycin Resistance ، Methicillin Resistance