For my microbiology class I'm supposed to look up a bacteria in Bergey's. Where do I go for that?


The book you will want to use is called Bergey's Manual of Determinative Bacteriology which is located in the Reserve section, call number QR81 .B47 2000. Students can borrow the book for up to 2 hours.  


How to use Bergey's Manual of Determinative Bacteriology

The first step is to determine your unknown's group number. To find your group number, look through the table of contents of the manual, and use the table that starts on page 17. Most unknowns will be in one of these groups:

  • Gram-Negative, Aerobic/Microaerophilic Rods and Cocci --Group 4
  • Facultatively Anaerobic Gram-Negative Rods --Group 5
  • Gram-Positive Cocci --Group 17
  • Endospore-Forming Gram-Positive Rods and Cocci --Group 18
  • Regular, Nonsporing Gram-Positive Rods --Group 19
  • Irregular, Nonsporing Gram-Positive Rods --Group 20
  • Aerobic, Nonmotile, Nonsporing, Acid-fast, Weakly Gram-Positive Rods --Group 21

Once you think you know your group number (or you have a few possibilities) go to the pages for your group within the manual. From there, you should find more information to help you make a final determination that you have the right group. You might also consult the information below to help you find the best tables to make a final determination about your unknown's group number:

Group #

Table to reference in Bergey’s Determinative, 9th edition

Key differences between genera in this group, as described in the Bio 205L manual


Table 4.1, pp. 103-116

pigments/fluorescent, motility, growth requirements, denitrification, morphology, oxidase


Table 5.1, pg. 202

growth factors, morphology, gram reaction, oxidase


Aerobic genera: Table 17.1, pg 534


Facultatively anaerobic genera: Table 17.2, pg. 535-536


Strictly anaerobic genera: Table 17.3, pg. 537

oxygen requirements, morphology, growth requirements (45°C and supplements)


Table 18.1, pg. 562

oxygen requirements, motility, morphology, catalase


Table 19.1, pg. 568

morphology, oxygen requirements, catalase


Aerobic genera: Table 20.1, pg. 583-584


Facultatively anaerobic genera: Table 20.2, pg. 585-586


Strictly anaerobic genera: Table 20.3, pg. 587-588

catalase, motility, morphology


Table 21.1, pg 598


acid fast, growth


Step 2: Determine the genus of your unknown.

To determine the genus of your unknown, you'll need to keep using Bergey's Manual of Determinative Bacteriology (9th edition). You should have the right group number by now, so go to the pages for your group. These pages should help you identify the genus of your unknown. There might be both tables and descriptions to help you identify the genus. You might find more than one possible match -- that's ok. The next step should provide more information to help you narrow down to a final choice.

Step 3. Read about your genus to make sure you have a match.

Step 4. Identify your unknown to the species level.

The genus description should contain information that helps you differentiate the species in your genus – so, you can compare your lab results to attempt to identify the species of your unknown. Be sure to read both the genus and the species descriptions, because characteristics listed in the genus description aren’t repeated in the species description!

Step 5. Troubleshoot problems.

If you find that the tables in Bergey's Manual of Determinative Bacteriology, 9th edition only allowed you to identify your bacteria down to the family level, then search the Systematic manual for your family name to see if the family description contains the tables you need to narrow down from family to genus. 

Also keep in mind that sometimes a taxonomic name can be declared a synonym of another name, and thus is no longer used. Try looking your name up in either of these two resources: 

If you find that another name is being used, look that name up in Bergey's instead. For example, the genus name Aurobacterium has been synonomized with Microbacterium, so you'd look up Microbacteriuminstead

Adapted from Nothern Arizona University LibGuide URL:


  • Last Updated May 21, 2024
  • Views 46
  • Answered By Lauren Saslow

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