Title:The Epidemiological and Pangenome Landscape of Staphylococcus aureus
and Identification of Conserved Novel Candidate Vaccine Antigens
Volume: 19
Issue: 1
Author(s): Kanwal Naz , Nimat Ullah, Anam Naz, Sidra Irum, Hamza Arshad Dar, Tahreem Zaheer, Fatima Shahid and Amjad Ali *
Affiliation:
- Atta-ur-Rahman School of Applied Biosciences (ASAB), National University of Sciences and Technology (NUST), Islamabad
44000, Pakistan
Keywords:
Epidemiology, Staphylococcus aureus, MLST, MRSA, pangenome, subtractive proteomics, vaccine candidates.
Abstract: Background and Objective: Staphylococcus aureus (S. aureus) is a gram-positive bacterium
and one of the major nosocomial pathogens. It has the ability to acquire resistance against almost
all available classes of antibiotics; Methicillin-Resistant S. aureus (MRSA) is a well-known
antibiotic-resistant pathogen. S. aureus is a globally distributed pathogen that needs in-depth epidemiological
and genomic level investigation for proper treatment and prevention.
Methods: To explore the genomic epidemiology of S. aureus, in-silico Multi Locus Sequence Typing
(MLST) was carried out for 355 complete genomes. Diversity within the species was investigated
through pan-genome analysis and a subtractive genomic approach was employed for the identification
of the core immunogenic targets.
Results: Epidemiological study identified 62 different sequence types (STs) of S. aureus distributed
worldwide, in which ST-8, ST-5, ST-398, ST-239, and ST-30 were the most dominant STs comprising
more than 50% of the isolates. The pan-genome of S. aureus is still open with 7,199 genes
and there is a major contribution (80%) of MRSA strains in the S. aureus species pangenome. The
core genome (2,025 genes) of S. aureus is almost stable (comprising 72% of S. aureus genome
size), while accessory and unique genes (28% of S. aureus genome size) are gradually increasing.
Screening of 2,025 core genes identified putative vaccine candidates. The best scoring and dominant
B-cell and T-cell epitopes were predicted out of the selected potential vaccine candidate proteins
with the help of a multi-step screening procedure.
Conclusion: We believe that the current study will provide insight into the genetic epidemiology
and diversity of S. aureus, and the predicted epitopes against the pathogen can be tested further for
their immunological responses within the host and may provide both humoral and cellular immunity
against the disease.
