Phylogenomic study of <i>Staphylococcus aureus</i> and <i>Staphylococcus haemolyticus</i> clinical isolates from Egypt

Abstract Antibiotic resistant Staphylococcus infections are a global concern, with increasing cases of resistant Staphylococcus aureus and Staphylococcus haemolyticus found circulating in the Middle East. While extensive surveys have described the prevalence of resistant infections in Europe, Asia, and North America, the population structure of resistant staphylococcal Middle Eastern clinical isolates is poorly characterized. We performed whole genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital. Supplemented with additional publicly available genomes from the region (34 S. aureus and 6 S. haemolyticus ), we present the largest genomic study of staphylococcal Middle Eastern isolates. These genomes include 20 S. aureus multilocus sequence typing (MLST) types and 9 S. haemolyticus MLSTs, including 3 and 1 new MLSTs, respectively. Phylogenomic analyses of each species core genome largely mirrored MLSTs, irrespective of geographical origin. The hospital-acquired spa t037/SCC mec III/MLST CC8 clone represented the largest clade, comprising 22% of S. aureus isolates. Similar to other regional genome surveys of S. aureus , the Middle Eastern isolates have an open pangenome, a strong indicator of gene exchange of virulence factors and antibiotic resistance genes with other reservoirs. We recommend stricter implementation of antibiotic stewardship and infection control plans in the region. Impact Statement Staphylococci are under-studied despite their prevalence within the Middle East. Methicillin-resistant Staphylococcus aureus (MRSA) is endemic to hospitals in this region, as are other antibiotic-resistant strains of S. aureus and S. haemolyticus . To provide insight into the strains currently in circulation within Egypt, we performed whole genome sequencing of 56 S. aureus and 10 S. haemolyticus isolates from Alexandria Main University Hospital (AMUH). Through analysis of these genomes, as well as other genomes of isolates from the Middle East, we were able to produce a more complete picture of the current diversity than traditional molecular typing strategies. Furthermore, the S. haemolyticus genome analyses provide the first insight into strains found in Egypt. Our analysis of resistance and virulence mechanisms carried by these strains provides invaluable insight into future plans of antibiotic stewardship and infection control within the region. Data Summary Raw sequencing reads and assembled genomes can be found at BioProject Accession number PRJNA648411 ( ncbi.nlm.nih.gov ).