Microbiology for the Aviculturist

Being able to do your own cultures and or gram stains can be essential tools to help you determine if and what problems might be brewing in your aviary.

This is especially important in the avian nursery. A sick baby needs help immediately, and being able to quickly and inexpensively do cultures for the major gram negative bacteria adds a big gun to your arsenal in aviary management. It lowers your costs, enables you to culture your birds frequently and shortens the up to week long waiting time that most commercial laboratories take to give culture results to only 48 or 72 hours. It costs about $5 to do your own culture, while it might cost anywhere between $40 to $50 to have the cultures sent out to a commercial lab. It is still advisable and sometimes necessary to use a commercial lab for certain types of tests, but testing for e.coli, salmonella, candida, etc. can be done quickly and easily in the aviary.

The ability to do your own cultures can be especially meaningful to the aviculturist who lives in an isolated area and doesn’t have quick and easy access to a veterinary clinic.

In order to do a culture, the following materials are necessary:

  • culture plates – selective agar plates, usually containing 1 or more agars.
  • sensitivity plates- to determine what antibiotic is necessary to treat the specific organism involved
  • an incubator to grow the microorganisms
  • antibiotic sensitivity disks
  • sterile inoculation loops for plating and streaking
  • antibiotic sensitivity zone ruler for reading sensitivity zones
  • color bacterial flow chart (optional)
  • atlas of or other microbiology text
  • record book or cards to record results Doing a culture involves the growth and identification of microorganisms on culture media. The results reveal the status of the birds system by showing both the pathenogenic and the nonpathenogenic organisms present. A healthy bird should always have “good” nonpathenogenic flora present in its system.A culture is done by taking a bacterial or fungal sample from a site and transferring it to a culture plate. Culture plates must be refrigerated, and should be removed from the refrigerator one hour before the culture is done. The plates should always be kept upside down, that is to say with the clear cover to the table and the media side up. This allows all excess moisture to stay on the cover and avoids contamination of the agar itself. Most plates give off some degree of moisture. The plate should be left out and be allowed to reach room temperature before the plate is used.

The culture should be done in a draft free area so that no air currents carry airborne contaminants onto the plate. Also avoid breathing directly on or touching the surface of the agar with anything other than the inoculation loop in order to eliminate any form of contamination which would prejudice the results.

A culture plate can contain one or multiple types of agar. The most common types used as culture media to check for the pathogenic gram negative bacteria that infect birds are EMBL, Blood Agar and Mac Conkey Agar.

The plate is inoculated with the sample. It is then placed in an incubator at 98.5% and allowed to grow for 18 to 24 hours. At the end of which time, the sample is checked for growth. If growth is evident, a sample is taken from this plate and placed onto another plate, a sensitivity plate. Mueller Hinton agar is the most common medium used for sensitivity testing. The sensitivity plate is inoculated and streaked with the cultures that grew on the first plate. Antibiotic sensitivity disks are then placed evenly around the plate and this plate is returned to the incubator for another 18 to 24 hours. After this time, the Mueller Hinton plate is checked and the different sensitivity zones on the plate are read and interpreted and an appropriate antibiotic is chosen.

There are two kits that can be purchased to get you started doing your own cultures. Both have everything but the incubator and the appropriate antibiotic sensitivity disks. They are the Birdseye kit by Microbio, Tempe AZ. 1 (800) 642-7624 , and the BactiStar culture System from Troy Biologicals. Troy Biologicals doesn’t sell direct to individuals, you must use a distributor. I use Physicians Laboratory Supply Co. 1 (800) 445-6507 . Both kits have quad plates , but the sensitivity plate in the Birdseye Kit is a separate plate, while the Bactistar sensitivity plate is attached to the quad plate. The advantage to having two separate plates is that if the bird only cultures nonpathogenic flora, you don’t need to use a sensitivity plate which saves you money and equipment. The Birdseye Kit also gives you an extra culture medium, Biggy Agar in a separate tube. Biggy agar is used to test for candida.

Both quad plates test for the following gram negative bacteria: E. Coli, Enterobacter, Enterococci, Klebsiella, Proteus, Pseudomonas, Shigella, Salmonella, etc. I suggest using the following antibiotic sensitivity disks, but you might want to discuss this with your vet for their input: SXT, Cephalexin, Amikacin, Cipro or Enrofloxin, doxycycline, Gentocin, pippercillin, clavamox, chloroamphenicol. A gram scale is necessary to weigh your bird so that accurate medication dosages can be calculated.

Both Microbio and Physicians Laboratory Supply Co. sell plates and other culture equipment. Plates can be purchased in groups of ten.

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