Spirochaetes in the equine caecum.

The research article discusses the discovery of two types of spirochaete bacteria in the horse’s caecum and indicates unsuccessful attempts at culturing the bacteria beyond the initial isolation, due to infection by bacteriophages.

Identification of Spirochaetes

• The researchers found two distinct types of spirochaete bacteria residing within the horse’s caecum. These spiral-shaped bacteria are typically involved in diseases such as syphilis and Lyme disease, however, no specifics on the exact species or their potential pathogenic nature are outlined in this abstract.
• The two types of spirochaetes were differentiated based on their size. The first type measured 4 to 6 microns in length and 0.3 to 0.4 microns in width. The second type had measurements of 6 to 8 microns in length and 0.1 to 0.2 microns in width.

Efforts to Culture Spirochaetes

• The study involved attempts to grow these bacteria in a controlled laboratory setting. The objective of this would presumably be to further study their structure, behaviour, and any potential impact they could have on the horse’s digestive health.
• Unfortunately, these attempts were unsuccessful, as none of the bacteria could survive subculture beyond the primary isolate. This suggests that the spirochaetes may have specific environmental requirements which were not met in the laboratory setting, thereby impeding their growth and survival.

Infection by Bacteriophages

• The use of electron microscopy revealed that many of the spirochaetes were infected by bacteriophages, viruses that infect bacteria. These bacteriophages could likely be a contributing factor to the difficulty in culturing the spirochaetes beyond the primary isolate.
• The presence of bacteriophages among the populations of these bacteria could prove significant. It could provide an insight into the biological life cycle of spirochaetes in the equine caecum, and even inform potential treatments or interventions if these bacteria were ever to cause disease in horses.