Survey of hospital environment regarding the presence of Staphylococcus aureus producing β-lactamase

Staphylococcus aureus is a common cause of hospital-acquired infections. This bacterium is resistant to β-lactam antibiotics. The aim of this study was to evaluate the prevalence of S. aureus strains producing enzymes capable of destroying β-lactam antibiotics in a hospital environment. This descriptive and analytic study was performed in Besat Hospital, Sanandaj, Iran, ۲۰۱۶, on ۱۵۸ swabs collected from the hospital environment. The S. aureus bacteria were identified by microbiology methods, and β-lactamase was determined using acidometric and combined disk methods, as well as Hodge test. Data analysis was conducted using Chi-squared and two-way analysis of variance in SPSS software, version ۱۶ (P<۰.۰۵). Out of ۲۰۱ isolated bacteria, ۷۴.۶۸% were S. aureus. Regarding the results of acidometric method, ۲۲.۸۸% of the strains was β-lactamase producing. In combined disc method, ۵.۰۸% of strains produced Metallo-β-lactamase; and according to the Hodge test, ۸۴.۵۰% showed carbapenemases. In places with repetitive cleaning, fewer isolates of bacteria were isolated (P<۰.۰۵). There was no significant difference between the results of the three methods (P>۰.۰۵). In this study, the β-lactamase producing strains of S. aureus isolates were observed in the hospital. Therefore, the periodic monitoring of resistance and using appropriate detergents are very important at hospitals.

Keywords:

Staphylococcus aureus , Phenotypic method , Enzymic degradation of β-lactam antibiotics , Hospital environment