Background: Staphylococcus aureus (S. aureus), an important pathogen, causes a wide
range of infections in human starting from food poisoning to septicemia. It affects the host cells with
various exotoxins, known as virulence factors, which are synthesized in growth phase-dependent manner
of the bacteria. S. aureus has been reported to become resistant to antibiotics rapidly. Among two
common clinical isolates, Methicillin-sensitive S. aureus (MSSA) and Methicillin-resistant S. aureus
(MRSA), MRSA pose major problems across hospitals around the world.
Objective: The objective of the present study was to profile the exoproteins of Methicillin-sensitive S.
aureus (ATCC 25293) and subsequently to establish a proteomics-based method of characterization of
S. aureus that is crucial in treating hospital-acquired infections.
Method: We used two-dimensional nanoLC/ESI-MS based proteomic platform to characterize and
quantify the exoproteins isolated from Methicillin-sensitive S. aureus (ATCC 25293) strain.
Results: A total of 69 proteins were identified from extracellular proteome pool of ATCC 25293 strain
that includes 18 extracellular proteins, 40 cytoplasmic proteins, 2 membrane proteins, 3 cell wall proteins
and 6 uncharacterized proteins.
Conclusion: We propose that this mass spectrometry-based proteomics method of characterization of
exoproteins might be useful to identify S. aureus strains that are resistant to antibiotics.