Comparison of Salmonella enterica serovar Abortusequi isolates of equine origin by pulsed-field gel electrophoresis and fluorescent amplified-fragment length polymorphism fingerprinting.

This research article investigates the genetic similarities and differences between various strains of Salmonella enterica serovar Abortusequi, which causes equine paratyphoid, primarily abortion in mares. Using two genetic analysis techniques, the team compared strains of the bacteria from Japan with others from around the world.

Introduction to the Research

• In this study, the researchers focused on Salmonella enterica serovar Abortusequi. This bacterium is responsible for equine paratyphoid, a condition that primarily causes miscarriages in equines.
• Their main goal was to understand the genetic similarities and differences of this strain of salmonella collected from different geographical areas.
• They compared strains found in Japan with those found in various other countries.

Pulsed-field Gel Electrophoresis Analysis

• The first method the researchers used to study the bacteria was pulsed-field gel electrophoresis (PFGE), a lab technique that enables the separation and analysis of large DNA.
• The PFGE analysis yielded between 21 to 27 fragments for each S. Abortusequi strain, with sizes ranging from 33 to 602 kilobases (kb).
• The Japanese isolate presented two different PFGE profiles, but they still shared common restriction fragments originating from the chromosome.
• These two profiles exhibited a similarity index of 90.9%. In comparison, the Japanese strain’s similarity indices with strains from other countries ranged from 29.8 to 37.5%, indicating a lower level of genetic similarity.

Amplified-fragment Length Polymorphism Analysis

• The second technique the team used was a fluorescent amplified-fragment length polymorphism (FAFLP) analysis. This is another type of genetic analysis technique that can detect and measure DNA fragment lengths in a sample.
• The FAFLP analysis generated between 64 and 67 amplified fragments for every examined S. Abortusequi strain, with lengths varying from 100 to 400 base pairs (bp).
• Only a single polymorphic fragment was observed among the 20 S. Abortusequi samples originating from Japan, suggesting a high level of genetic similarity amongst this group.

Conclusion

• The researchers concluded that the S. Abortusequi strains in Japan were closely related.
• The strains that share common ancestry might have been conserved in Japan, with their genetic material remaining stable over time.
• This research provides insight into the genetic makeup of the bacterium, which could aid future efforts in controlling and treating equine paratyphoid.