Research Information System
Thesis Type: Postgraduate
Institution Of The Thesis: Gazi University, Turkey
Approval Date: 2019
Thesis Language: Turkish
Student: Müge Kera
Supervisor: NESLİHAN GÜNDOĞAN
Open Archive Collection: AVESIS Open Access Collection
Abstract:The aim of the present study is to investigate the slime, biofilm, lipase, lechitinase, gelatinase, DNase, hemolysin and siderophore production, amino acid decarboxylase activity and antibiotic resistance of 67 Bacillus spp. isolates from 100 raw milk, cheese and ice cream samples purchased from open bazaars, pastry shops and dairy plants in Ankara. The present study is also carried out to identify slime, biofilm, hemolysin, siderophore and aminoacid decarboxylase properties, antibiotic resistance and extended spectrum β-lactamase (ESBL) production of 20 Esherichia coli isolates isolated from these samples. Of the 67 Bacillus isolates, 36 (53.7%) were identified as Bacillus subtilis, 12 (17.9%) as Bacillus cereus,10 (14.9%) as Bacillus megaterium, 6 (9%) as Bacillus licheniformis, 2 (3%) as Bacillus circulans, 1 (1.5%) as Bacillus brevis. A high proportion of Bacillus isolates had slime formation (94.1%), biofilm formation (88.1%), hemolytic activity (79.1%), DNase activity (79.1%), lipase production (79.1%), gelatinase production (76.7%), siderophore production (62.7%), protease production (61.2%), lechitinase production (41.8%). The frequency of positive slime formation, biofilm formation, siderophore production and hemolysis for E. coli isolates were 100%, 90%, 70% respectively. Decarboxylase activity was quite common for Bacillus isolates and 100% of the isolates could decarboxylate arginine and histidine. The isolates also could decarboxylate tyrosine (98.5%), lysine (92.5%), ornithine (92.5%). The ability to decarboxlate lysine, ornithine and tyrosine was present in all isolates of E. coli 100% and 65%, and 60% of the isolates also decarboxylate arginine and histidine respectively. Resistance to antimicrobials was tested in all Bacillus and E. coli isolates by the disk diffusion method. The double-disk synergy test was used to determine ESBL production in E. coli. Bacillus isolates were found to be resistant to (79.2%) novobiosin, (71.6%) ampicillin, (70.1%) bacitracin, (67.2%) penicillin, (52.2%) erythromycin, (16.4%) tetracycline, (11.9%) vancomycin, (7.5%) chloramphenicol and (7.5%) amikacin. ESBL production was detected in 16 (80%) E. coli isolate. The study also showed that E. coli isolates exhibit to (100%) ampicillin, (55%) gentamicin, (50%) chloramphenicol, (45%) ceftazidime, (40%) aztreonam, (40%) tetracycline, (30%) amoxicillinclavulanic acid, (30%) ciprofloxacin, (30%) amikacin, (25%) cefotaxime, (15%) ceftriaxone, (15%) ertapenem but sensitive to (100%) imipenem