▪Learn and observe the proper procedures inpreparing bacterial smears aseptically from brothand solid medium▪Purpose of making bacterial smears▪Know the different method of fixation andunderstand its principle
Thin layer of bacteria placed on a slide for stainingand microscopic visualization
Spreading small volume ofsample on a slide and airdrying the film beforestaining and microscopy.Robert Koch
▪Fix the bacteria onto the slide and to prevent thesample from being lost during a stainingprocedure.▪Prevent contamination of the culture and ensure thesafety of the preparerPreparationof BacterialSmearFixationStaining
▪Disinfecting the work area such as table tops before andafter use▪Minimizing the time that cultures and growth media are opento the environment.▪Avoiding touching or breathing into the sterile culture mediaor the stock cultures.▪Sterilizing loops, needles, pipettes and other tools beforeand after they are used▪Refraining from placing tube caps on the table top.▪Holding the tube caps in the hands while inoculating▪Flaming the lip of test tube after the cap is removed
▪Preserve the morphology and prevent smear beingwashed away during staining.▪Kills the organism and facilitates stain penetrationHEAT FIXATIONALCOHOL FIXATION•After smear is air driedcompletely, rapidly pass the 3-4times through flame of Bunsenburner or sprit lamp.•Avoid too much heating.•After heat fix, allow the smear tocool before staining.•Allow smear to air dry completely•Fix the smear with one or twodrops of 70% alcohol, and leave itfor 2 minutes until the alcoholdries up.
EngelkirkP.G. (2015). Burton’s Microbiology for Health Science 10th EditionCecil Starr, Christine A. Evers, Lisa Starr (2016), Biology Concept and Application 10th EditionLeong AS-Y. Fixation and fixatives. In Woods AE and Ellis RC eds. Laboratory histopathology. New YorkPreparation of a bacterial smear for staining. (n.d.). Welcome to the Instructional Microbiology Server.
BACHELOR OF SCIENCE IN BIOLOGY:MICROBIOLOGY LABORATORYLABORATORY EXERCISEWEEK5BACTERIAL SMEARS5At the end of this exercise, each student must be able to:oLearn and observe the proper procedures in preparing bacterial smears aseptically from a brothmedium and a solid medium for the microscopic visualization of bacteriaoExplain the purpose of making bacterial smearsoKnow the different methods of fixation and understand the principle behind these methodsINSTRUCTIONS•Study the procedure in preparing bacterial smears from different culture media•Watch the video tutorials on how to prepare bacterial smears.