Study of Biofilm Formation and Antimicrobial Resistance Staphylococcus aureus Isolated from Handmade Sweets in Hamadan

Background and Aims: Staphylococcus aureus is one of the most common causes of food poisoning, which due to excessive use of antibiotics has become resistant to different antibiotics. In addition, it is also capable of producing biofilm. The aim of this study was to investigate antibiotic resistance patterns and phenotypic study of biofilm production in S. aureus isolates separated from confectionary pastries in Hamadan. Materials and Methods: In this descriptive- cross-sectional study, 370 samples of creamy (280) and dried (90) pastries were collected randomly (May to February 2017). To separate possible microbial contaminations, part of samples were cultivated with conventional microbiological methods. The separated S. aureus isolates were confirmed using polymerase chain reaction (PCR) and nuc gene amplification. The antibiotic susceptibility pattern of all isolates was determined by disk agar diffusion (DAD) method based on CLSI guideline and also, microplate modified method was used to identify biofilm strains. Results: The results showed that 34.64% of the creamy pastries and 3.33% of the dried pastries were infected with S. aureus. Antibiogram results showed the highest resistance was related to penicillin (90%). In the quantitative study of biofilm production, 42 strains (42%) were strongly adhesive, while 17 (17%) and 41 (41%) strains were weakly adhesive and lacking adhesive ability, respectively. Conclusions: Consumption of creamy pastries increases the risk of infection with S. aureus and is a serious warning to the health system. Pasteurization and storage of food stuff in the refrigerator, continuous microbial control of pastries and the screening of the confectionary staff can reduce the level of microbial contamination and the risk of staphylococcal poisoning.