372. Recognition of Some Unique Virulence Characteristics for Methicillin Resistant Staphylococcus aureus
Session: Poster Abstract Session: MRSA, MSSA, Enterococci
Thursday, October 3, 2013
Room: The Moscone Center: Poster Hall C

Methicillin resistant Staphylococcus aureus (MRSA) strains emerged in the late of 1960s. They rapidly distributed in both community and hospital settings causing several diseases in human including skin infections, endocardities, pneumonia, mastitis, arthritis, osteomyelitis, and sepsis. To unravel the methicillin resistant determinants of this important microorganism, two clinical isolates of methicillin susceptible S. aureus (MSSA) and MRSA were subjected to comparative proteomics analysis of their exoproteins using 1D-SDS-PAGE- LC-MS/MS.


MSSA and MRSA clinical strains isolated from skin abscess were cultured in tryptic soy broth to stationary phase of growth. Exoproteins were precipitated using trichloroacetic acid, washed with ice cold acetone, and dissolved in SDS sample buffer. The proteins were separated on a SDS-PAGE gel and cut into 13 slices. Each slice was reduced, alkylated, and digested with trypsin. The tryptic digests were analyzed by nanoflow LC-linear iontrap-TOF MS. Data processing and databank searching were performed with Mascot software against NCBInr database. Bioinformatic tools were used for successive analysis.


The number of proteins identified from the spent media of MSSA and MRSA were 168 and 262 proteins; respectively, from them 118 was shared. The MRSA unique proteins were 144. They are classified according to their function and location. Around 41.7% were virulence determinants, 10% involved in carbohydrate metabolism, 15.7% in protein synthesis, 9.4% in cell division, 5.8% in transcription and replication, and 17.4% were miscellaneous and unknown function. Seven hypothetical proteins seem to be unique to S. aureus. MRSA unique proteins location was predicted using Psortb2 software, 48.7% were extracellular, 16.7% cytoplasmic, 3.5% cell wall, and 31.1% had unknown localization. Characteristics determinants for MRSA were identified like pyruvate dehydrogenase (lipoamide) subunit E1beta, cysteine protease, molybdopterin biosynthesis protein, and transcriptional repressor CodY.

Conclusion: Identification of novel determinants for MRSA will help for their treatment in the medical community.

Shymaa Enany1,2 and Tadashi Yamamoto2, (1)Microbiology and Immunology Department, Faculty of Pharmacy, Suez Canal University, Ismailia, Egypt, (2)School of Medical and Dental Sciences, Niigata University, Niigata, Japan


S. Enany, None

T. Yamamoto, None

Findings in the abstracts are embargoed until 12:01 a.m. PST, Oct. 2nd with the exception of research findings presented at the IDWeek press conferences.