Differential Staining & Specialized Media
 Identification of Unknown Bacteria Laboratory Exercise



MacConkey's Media growing E. coli, Enterobacter & Salmonella (clockwise from left top)
ANAT & PHYSGENERAL BIOCELL BIOMICRO 8wkMICRO 15wkINSTRUCTORS


Lab #3: Differential Staining & Specialized Media

This is the main page for the Differential Staining & Specialized Bacterial Growth Media Laboratory Topic of an 8-week introductory college microbiology class. This is part of a series of three labs, in the Virtual Microbiology Classroom, on identifying unknown bacteria, also see Lab #2 and Lab #4

Microbiology Photo Image Library
SCIENCE PHOTOS



Photographic guides to differential stains 
now available!
1. Gram
2. Acid-fast
3. Endospore

 Illustration of Unknown and Control Bacteria Used in Differential Stains
Go to Virtual Microbiology Classroom Main
SPO VIRTUAL CLASSROOMS
How to Prepare a Bacterial Smear for Gram Staining
How to Prepare a Bacterial Smear for Acid-fast 
(Ziehl-Neelsen) Staining
How to Prepare a Bacterial Smear for Endospore Staining
How to Do a Gram Stain
How to Do an Acid-fast 
Ziehl-Neelsen Stain

How to Do an Endospore Stain
Tutorial on Compound Light Microscope Parts & Operation
MORE DIFFERENTIAL STAINING & SPECIALIZED MEDIA LINKS
  • Gram Stain Bite Sized Tutorial: This is an extremely useful tutorial that shows, step-by-step, the Gram-staining procedure and the appearance of Gram+ and Gram- bacterial cells.

DIFFERENTIAL STAINING & SPECIALIZED MEDIA LAB VIDEOS
DIFFERENTIAL STAINING & SPECIALIZED MEDIA LAB IMAGES
The images linked here directly relate to the lab exercise and are designed to help you review and study that lab material while outside of lab. 

​How to Interpret MacConkey's Agar (MAC) Specialized 
Bacterial Growth Medium
​How to Interpret Mannitol Salt Agar (MSA) Specialized 
Bacterial Growth Medium
Microbiology Lab Videos
SCIENCE VIDEOS
NOTE: Students must review all material in categories highlighted with red titles  PRIOR TO ATTENDING LAB in order to be prepared to participate. ​​​

DIFFERENTIAL STAINING & SPECIALIZED MEDIA 
LAB DOCUMENTS
​The Lab Exercise Instructions are the main resource required for students to understand and complete this exercise. They provide a thorough explanation of the lab topic, as well as detailed directions on how to complete the exercise. The Lab Report Assignment is the homework that students complete and turn in.

​Additional Lab Documents:

The ID of Unknown Bacteria Lab materials include:
  • Lab Exercise & Report documents
  • Laboratory PowerPoints
  • Laboratory required readings
  • Videos & images related to the lab
  • Additional links that support the lab material

DIFFERENTIAL STAINING & SPECIALIZED MEDIA LAB POWERPOINTS
The lab PowerPoints used to introduce the material in the related Lab Exercise Instructions & Report Assignment.
​​
Printing: The best way for students to print out the PowerPoint Show is to download the PDF version. Select Print, and, when the Print screen comes up, go to the Print Handling options. Under Page Scaling, select "Multiple pages per sheet", Under Pages per sheet, select "2". That uses up less paper, placing two slides on each page.
Ziehl Neelsen stain showing both acid-fast Mycobacterium (pink) and Staphylococcus (purple)
A mixed slide of acid fast Mycobacteria (hot pink) and non-acid fast  Staphylococcus (purple).
 Illustration of Unknown and Control Bacteria Used in Differential Stains
Diagram on white board of bacterial controls used for Gram, Acid-fast-and Endospore differential staining of bacterial smears. Positive control on left, negative control on right, unknown bacteria in center.
Page last updated: 2/2016
Virtual Microbiology
Classroom






You have free access to a large collection of materials used in a college-level introductory microbiology course. The Virtual Microbiology Classroom provides a wide range of free educational resources including PowerPoint Lectures, Study Guides, Review Questions and Practice Test Questions.
Prokaryotic Cell, Mariana Ruiz
The VMC offers homework assignments based on Radiolab podcasts. 

RADIOLAB PODCASTS: 
 "Patient Zero"
"Parasites"
"Rodney vs Death"

HOMEWORK ASSIGNMENTS:
Patient 0 HW doc
Parasites HW doc
​- Rodney vs Death HW doc
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Monsters Inside Me TV Show on Parasitism from Animal Planet

Monsters Inside Me
TV show, from Animal Planet, presenting case studies of  people with parasitic infections. So interesting, you'll learn about parasitism without even trying!

Check out our FREE "Monsters Inside Me" Homework Assignments 
Part 1 & Part 2!