Abstract

Crystalline layer is the outermost protein in bacteria and archiae, and it inhibits antibiotics introduction due to increase of pathogenicity in bacteria. According to the role of health care workers and hospital surfaces in nosocomial infections, contamination of this source withBacillus cereus strains produce crystalline layer and beta lactamase as a result of the spread of antibiotic resistance of nosocomial infections. The aim of this study is to survey the frequency of nano structure of crystalline layer and beta lactamase nano enzyme, and the role of crystalline layer in antibiotics inhibition in B. cereus strains isolated from health care workers and hospital surfaces. The research was performed with laboratory method in Azzahra hospital and Isfahan University. 274 samples were used for the preparation samples, which include culture bacteria in TSA (tryptone soya agar), separated surface proteins and specimen's electrophoresis with 10X SDS-PAGE. Samples antibiogram were performed with Kirby Bauer method, and beta lactamase production was detected with acidimetric method. Based on the result of SDS-PAGE, 46.20% of the studied. B cereus strains were able to produce crystalline layer and 53.8% were unable to produce crystalline layer. According to the antibiogram result, the non-producer strain of crystalline layer, when compared with the producer strain was sensitive to antibiotics and to all the strains that produced crystalline layer and beta lactamase. The result showed high prevalence of B. cereus strains that produced crystalline layer and beta lactamase in the hospital sensitive environment, due to increase of the antibiotic resistance of nosocomial infection. As such, it is necessary to reduce the transfer of virulence agent and antibiotic resistance in pathogen bacteria.

Key words: Crystalline layer nano structures, Bacillus cereus, resistant, Beta lactamase, nosocomial infections, virulence.