During ovipositioning, avian eggshells become susceptible to bacterial and fungal growth and studies have
shown that a community of these microorganisms, or microflora, is maintained on eggshells throughout the incubation
process. To determine the possible role of these microorganisms on embryonic development, it is first important to understand
the composition of the microbial community present on the surface of the egg. A limited amount of studies have
been published in this area; thus, the objective of this study was to broaden this area of study and determine what bacterial
communities are found on the surface of naturally-incubated House Wren eggs across three stages of incubation (pre,
early, and late) as defined by egg temperature. Our data uniquely suggest that the eggshell microflora is dynamic and that
this may be regulated by temperature fluctuations due to intermittent incubation behavior. Using culture-based techniques,
46 different bacterial species were identified belonging to 13 bacterial families and 20 genera. The majority of bacteria belonged
to the Pseudomonas, Staphylococcus, Stenotrophomonas, or Burkholderia genera and have been previously associated
with avian eggs and nests. Bacteria within the Pseudomonas genus were the most predominant and we hypothesize
that their maintenance may be linked to their ability to produce antibiotic substances called bacteriocins. The bacterial
composition of the microflora isolated in this study also suggests that avian egg microfloras are derived from environmental
origins.
An Assessment of the Microbial Diversity Present on the Surface of Naturally Incubated House Wren Eggs
