Comparisons between geographically diverse samples of carried Staphylococcus aureus

Area of Science:

• Microbiology
• Population Genetics
• Epidemiology

Background:

• Staphylococcus aureus asymptomatically colonizes about one-third of the human population globally.
• Significant gaps exist in understanding the global diversity and geographic partitioning of Staphylococcus aureus carriage strains.

Purpose of the Study:

• To characterize the global diversity of Staphylococcus aureus carriage isolates.
• To investigate the geographic distribution and population structure of Staphylococcus aureus carriage strains across different continents.

Main Methods:

• Isolation and characterization of 300 Staphylococcus aureus carriage isolates from 1,531 adults across France, Algeria, Moldova, and Cambodia.
• Multilocus sequence typing (MLST) was employed to determine the genetic relatedness of the isolates.
• Phylogenetic analysis was conducted to identify novel lineages and population structures.

Main Results:

• Six clonal complexes (CCs) were found to be prevalent across all four sampled countries.
• Genotype frequency analysis indicated that French and Algerian samples were most similar, while Cambodian samples were most distinct.
• A novel, highly divergent Staphylococcus aureus genotype (ST1223) was identified in Cambodia, related to CC75 found in Australian aboriginal populations.

Conclusions:

• Geographic distance and human migration patterns influence Staphylococcus aureus carriage strain distribution.
• Stochastic clonal expansion plays a role in shaping regional differences in bacterial populations.
• The discovery of a novel lineage in Cambodia highlights the need for continued global surveillance of Staphylococcus aureus diversity.