New Selected Culture Medium With Trimethoprim and Rifampicin for the Growth of Lactococcus species.Kihal Mebrouk, Senouci Djamal, Benatia Saliha, Bensaid Naceraand Heddadji Miloud.
Applied Microbiology Laboratory, Department of Biology, Faculty of Natural Science and Life, University Oran1 Ahmed Benbella, Oran, Es-Sénia , 31100, Algeria
Lactic acid bacteria are a very heterogeneous group phenotypically. This group is characterized by the type of common criteria Gram positif, absence of catalase producing mainly lactic acid. The genus Lactococcus recently created includes non-haemolytic streptococci and homofermentative.The evaluationofexogenouslactococci dairysamplesisfrequentlyrequiredfortheevaluationof themilkcolonizationbyLactococci.Inthisstudy,different culture media, Elliker and M17-trimethoprimand M17 and Elliker rifampicin, have been tested forLactococcus strains isolated from raw goat's milk from the region of Oran.Aselectivemediumdesignated Elliker-Trimethoprim medium ETMwasdevelopedforthecultureofexogenousLactococcus sp.Inquantitativeassays,ETM showedsensitivity higher thanM17media. This medium allowed the selective growth of Lactococcus, the following species: Lactococcuslactissubsp. lactis, Lactococcuslactissubsp. cremoris, Lactococcuslactissubsp. lactis biovar. diacetylactis, Lactococcusplantarum and Lactococcusraffinolactis. This culture medium is a new microbiological tool that solved a problem of isolation of Lactococcus species which are much researched for food industry.After several tests, and comparative study, the Elliker-trimethoprim was chosen to follow the specific isolation and growth of Lactococcus species. Thepresenceof Trimethoprim madeETMinhibitoryto most milkbacteria,includingendogenouslacticacidbacteria,whereasLactococcus lactisstrainsgrew well.Identification morphological phenotype physiological, immunological and biochemical tests, confirmed the 40 isolates belonging to the genus Lactococcus.17 isolate (42.5%) belonging to the subspecies Lactococcus lactis subsp. cremoriswere revealed on Elliker-trimethoprim media. TheresultsshowedthatETMissuitablefordetectionandenumerationof Lactococcus lactis species in crud milksamples.
Biography
Kihal Mebrouk has completed his PhD at the age of 31 years from Oran University and postdoctoral studies from Oran University Biology department. He is the director of Applied microbiology laboratory. He has published more than 120 papers in reputed journals and has been serving as an editorial board member of repute.
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Full name: Kihal Mebrouk
Contact number:00213771252821
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