ISOLATION AND IDENTIFICATION OF Enterococcus STRAINS FROM OLD EGYPTIAN HARD CHEESE. | ||
| Journal of Food and Dairy Sciences | ||
| Article 2, Volume 3, Issue 2, February 2012, Pages 75-84 PDF (842.47 K) | ||
| Document Type: Original Article | ||
| DOI: 10.21608/jfds.2012.75305 | ||
| Authors | ||
| Nanis H. Gomah1; K. J. Heller2 | ||
| 1Dairy Department, Assiut University, Assiut, Egypt | ||
| 2Institute of Microbiology and Biotechnology, Max Rubner-Institut, Kiel, Germany | ||
| Abstract | ||
| Six bacterial strains were isolated from old Egyptian hard cheese, and identified by rapid ID 32 strep V2.0 as Enterococcus durans with 99.9 % identity. The strains were tested for growth under different stress conditions such as different temperatures (42, 46, 50, 55°C), antibiotic (Erythromycin EM) and different salt concentrations (1, 2, 3, 4, 5 % NaCl). One strain, which appeared to be rather resistant to the different stress conditions, was selected for determination the characteristics of the plasmid harboured by the strain. To study the biological functions of the plasmid, wild type and plasmid-cured derivatives were compared i) for resistance against different antibiotics (ampcillin AMP, chloramphenicol C, cefotaxime CTX, EM, gentamycin CN, kanamycin K, lincomycin MY, methicillin MET, neomycin N, ofloxacin OFX, rifampicin RD, streptomycin S, tetracycline TE, vancomycin VA), ii) resistance against high temperature and iii) for ability to grow at high salt concentrations. Results showed that there was no difference in antibiotics resistance for wild type and cured strain, except for S and VA (cured strain was less sensitive than the wild-type ) . Determination of growth rates of both strains in medium containing EM showed that the cured strain grew better than the wild type at 42°C, however, in the absence of EM the wild type strain grew better than the cured one at 42, 46 and 50°C. No significant differences between both strains were seen when they were grown at different NaCl-concentrations of 1, 2, 3, 4 and 5 %. | ||
| Keywords | ||
| Enterococcus durans; plasmid; antibiotics resistance; NaCl resistance | ||
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