Islamic University_Gaza Medical Technology Department Citrate Utilization Reham Sabri Hammad 2005\0076 Supervisor: Dr. Abdelraouf A. Elmanama 2007\2008
Outlines • Introduction. • Principle Of Citrate Test. • Significance Of Citrate Test. • Materials and Method. • Result. • Summary.
Introduction • Tests for the ability of bacteria to convert citrate (an intermediate of the Krebs cycle) into oxaloacetate (another intermediate of the Krebs cycle). • In this media, citrate is the only carbon source available to the bacteria.
PrincipleOfCitrate Test • To determine if an organism is capable of utilizing citrate as sole carbon source for metabolism with resulting alkalinity. • If organisms utilize citrate and ammonium salts, the medium becomes more basic and the bromthymol blue changes from green to blue as a result of an increase in the pH of the media. • If it can not use citrate then it will not grow.
Significance Of Citrate Test • A differential cultural test to identify genera within the bacterial family Enterobacteriaceae that are able to utilize sodium citrate as a sole source of carbon.
Materials • Simmons Citrate agar which contains : • sodium citrate (carbon source) . • ammonium salts (nitrogen source). • Bromthymol blue indicator. • Inoculating needle .
Method • Streak one organism over the surface of the agar slant, then stab the butt. • Incubate the tube at37°C for 48hours .
Result • Examine for growth (+) . • Growth on the medium is accompanied by a rise in pH to change the medium from its initial green color to deep blue.
Result • Some intestinal bacteria are (+)citrate as: Klebsiella. Citrobacter. Enterbacteraerogenes. • while others is(-) citrate as: E. coli
At last, I wish that you have enjoyed my presentation. • Thank you, and have a nice day please. • My best wishes
References • http://srv2.lycoming.edu/~diehl/321-f03/lecture2.htm 20\11 • http://whitewolf.newcastle.edu.au/techinfo/proc_bacto_biochem.html 20\11 • http://science.swu.edu/~wsinnamon/micrometabolism.htm 20\11 • http://web.fccj.edu/~lnorman/unknowns.htm?index=2 21\11