PCR based differentiation between Streptococcus dysgalactiae subsp. equisimilis strains isolated from humans and horses.

This research article discusses the creation of a PCR protocol capable of distinguishing between strains of the bacteria Streptococcus dysgalactiae subsp. equisimilis (SDSE) found in humans and those found in horses.

Introduction and Background

• The bacterial strain Streptococcus dysgalactiae subsp. equisimilis (SDSE) is commonly found in both humans and horses and can cause severe diseases in both species.
• However, it is often considered a commensal bacterium, meaning it usually lives harmlessly on or in the body without causing disease.
• Despite their similarities, a recent trend of SDSE-associated diseases specifically within horse populations is being noticed, raising concerns about strain differentiation.

The PCR Protocol

• To address the need for better differentiation, the researchers developed a multiplex PCR (polymetric chain reaction) protocol, a technique that amplifies DNA from the bacteria to help identify it.
• This particular protocol targets two specific genes: the 16S rRNA gene, a commonly used benchmark for bacterial identification, and the streptokinase precursor gene, which is involved in the bacteria’s virulence or disease-causing capability.
• The protocol was created to be able to separate and identify strains of SDSE originating from humans from those found in horses.

Implications and Future Work

• This PCR protocol, however, needs further testing for validation, as so far the streptokinase precursor gene from SDSE in horses has been reported in only two human cases of pneumonia in Japan, suggesting transmission between species.
• The findings imply the host-specific nature of different SDSE strains, which can be crucial in understanding and controlling potential zoonotic (animal-to-human) transmission scenarios.
• The authors proposed that their PCR protocol could be highly useful in future epidemiological studies and in studying the zoonotic capacity of SDSE.