Specialized Bacterial Growth Media: Mannitol Salt, MacConkeys & Blood Agar (clockwise from left)


Types of Culture Media Used for 
Growing Bacteria 


GEN BIOCELL BIOMICROBIOLOGYHOMESCHOOL SCIENCEINSTRUCTORSABOUT SPO



Like captive animals in a zoo, bacteria grown in a laboratory environment need to have everything provided for them—food, water, a suitable environment—in order to survive and thrive. 
Article Summary: Many types of bacterial growth media are used to culture (grow) microbes in the laboratory. Here's a summary of defined, complex, selective and differential media. 
Types of Growth Media Used to Culture Bacteria
More Images of Bacterial Growth Media Button
SCIENCE PHOTOS
SPO VIRTUAL CLASSROOMS
be thought of as a crowd-pleaser, suitable for growing many different types of less fastidious microbes.

In addition to growth media formulations being classified as either defined or complex, there are also specialized media that are designed to do more than just grow bacteria, selective and differential media provide information about the bacteria growing.

Some microbes are not especially choosy in their requirements for growth, while others, such as Treponema pallidum, the causative agent of syphilis, has never been successfully grown in culture, although scientists have been trying to do so for more than 100 years.

Several basic types of media are discussed below. Although their differences are featured, there are several characteristics that all culture media have in common: 

  • Media must be prepared in such a way that it is sterile prior to being inoculated with a bacterial sample, so that when a particular type of bacteria is cultured (cultivated) on that medium, it is the only type of bacteria present. 

  • Growth media must also provide everything the bacterial culture needs to live and grow, including water, nutrients, and the proper pH. Media can be either liquid (nutrient broth) or solid (agar).


Defined Media versus Complex Media
Some media formulations are very specific recipes in which certain ingredients must be present in specific amounts. These defined media (also known as synthetic media) are used to grow bacteria that have very particular needs.

Instructor's Corner
Continued ... 
Go to PAGE 2 >
Tryptic Soy Agar (TSY) is a good all-purpose medium commonly used to grow bacteria in the microbiology laboratory.
Most clinical cultures do not have such exacting requirements, and can be grown in what is referred to as “complex media”. Complex media are composed of partially digested yeast, beef, soy and additional proteins, in which the exact concentration and composition is unknown. In comparison with defined media, which are good for growing bacteria with very particular needs, complex media can
Tryptic Soy Agar (TSY) is a good all-purpose medium commonly used to grow bacteria in the microbiology laboratory.
Virtual Microbiology
Classroom





You have free access to a large collection of materials used in two college-level introductory microbiology courses (8-week & 16-week). 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
​Page last updated: 7/2015
Instructor's Corner
This article has 
3 pages: 
1  . 2 .  3
Fluoresced Eukaryotic Cells, US Gov, NIH
SPO HOME SCIENCE PROJECT

Does Your Automatic Dishwasher Kill All The Prokaryotes Living On Your Dirty Dishes?

Click here to find out!


FREE Printable 
Differential  Bacterial Stains and Growth Media
Study Aid!, from Tami. You'll brain will thank me!
Selective Bacterial Growth Media
For example MacConkey’s Agar (MAC) is used to cultivate Gram-negative bacteria, by discouraging the growth of Gram-positive bacteria through the use of crystal violet dyes and bile salts. Another selective medium, Mannitol Salt Agar (MSA), has a high concentration of sodium chloride, which selects for halophiles (salt-loving bacteria) such as members of the genus Staphylococcus.

MacConkey's agar growing happy E. coli, a Gram-negative lactose fermenter.
MacConkey's agar growing happy E. coli, a Gram-negative lactose fermenter.
CLASS NOTES 
from the free STEM 
education site 
Science Prof Online