Determination of the effect antimicrobial and antibiophilm on enterobacteriaceae isolates of lactic acid bacteria

In recent years, probiotics have been seen as a natural alternative to antibiotics in the treatment of bacterial diseases. Lactic acid bacteria have an inhibitory effect on pathogenic microorganisms due to the bacteriocins produced. However, there are few studies on enteropathogenic bacteria inhibited by lactic acid bacteria. Therefore in this thesis, the effects of antimicrobial, antibiofilm lactic acid bacteria against Enterobacteriaceae strains and exopolysaccharide production were investigated. In this study, both congo red agar and microtitre plate method were used to detect biofilm formation. As a result, all isolates were found to form biofilm. The isolates that found produce biofilm were identified by BD PhoenixTM automation system. According to Phoenix bacteria identification and antibiotic sensitivity test results, 4 isolates (P3, P4, P5, P7) were identified as Enterobacter cloacae, 3 isolates (P1, P2, P9) as Citrobacter braakii, 2 isolates could not make the species identification. According to the antibiogram test results amoxicillin-clavulanate and ampicillin resistance were determined in all isolates. Agar well and agar disc diffusion method were used to determine the antimicrobial effect of lactic acid bacteria on Enterobacteriaceae strains. Microorganisms were that high antimicrobial activity P2, P3 and P7. Also, the antibiofilm effect of lactic acid bacteria was tested on Enterobacteriaceae isolates. The highest antibiofilm effect showed Lactococcus lactis (L1) extract on P3 isolate (91,97%). Exopolysaccharide (EPS) production abilities of isolates were investigated to determine the adhesion capacity of LABs to intestinal epithelial cells. The highest EPS production (49,31 mg/mL) was observed in Enterococcus faecalis (L3). As a result, antimicrobial and antibiofilm effect compounds which obtained from LABs are considered to be usable against pathogenic microorganisms in both food and health industries.