Insertion elements in Staphylococcus intermedius

Area of Science:

• Microbiology
• Genetics
• Veterinary Science

Background:

• Staphylococcus intermedius is a bacterium found in various animals.
• Insertion elements are mobile genetic sequences that can influence bacterial traits.
• Antibiotic resistance in bacteria is a growing global health concern.

Purpose of the Study:

• To investigate the prevalence of insertion sequence (IS) elements IS256 and IS257 in Staphylococcus intermedius isolates from different animal hosts.
• To determine the relationship between the presence of these IS elements and antibiotic resistance patterns.

Main Methods:

• Bacterial DNA extraction from Staphylococcus intermedius isolates obtained from dogs, pigeons, horses, and mink.
• Hybridization assays using a gene probe for the IS257 transposase gene to detect and quantify IS element copies.
• Analysis of IS element location (chromosomal vs. plasmid DNA).

Main Results:

• IS256 was not detected in any of the tested Staphylococcus intermedius isolates.
• Single copies of IS257 were found in isolates from dogs and horses.
• Mink isolates did not contain IS257.
• Pigeon isolates harbored multiple copies of IS257, located in the chromosomal DNA.
• A high number of chromosomal IS257 copies in pigeon strains correlated with multiresistance.

Conclusions:

• The insertion element IS257 is present in Staphylococcus intermedius from certain animal hosts, with varying copy numbers.
• The prevalence and copy number of IS257 differ significantly between animal species.
• Multiple chromosomal copies of IS257 in pigeon strains are strongly associated with chromosomal multiresistance, suggesting a role in the evolution of antibiotic resistance in this bacterium.