Methicillin-susceptible Staphylococcus aureus MSSA

Shore AC, Rossney AS, O Connell B, Herra CM, Sullivan DJ, Humphreys H, Coleman DC (2008) Detection of staphylococcal cassette chromosome mec-associated DNA segments in multire-sistant methicillin-susceptible Staphylococcus aureus (MSSA) and identification of Staphylococcus epidermidis ccrAB4 in both methicilhn-resistant S. aureus and MSSA. Antimicrob Agents Chemother 52 4407-4419... 

The antibacterial effects of tea polyphenols extracted from Korean green tea (Camellia sinensis (L.) O. Kuntze (Theaceae)) against clinical isolates of methicil-lin-resistant Staphylococcus aureus (MRSA) were evaluated (Cho et al. 2008). Characterisation of the MIC of oxacillin for 30 Staphylococcus aureus strains isolated from patients treated with oxacillin identified 13 strains with an oxacillin MIC>4 pg/ml as MRSA (range 8-512 pg/ml), while 17 strains were methicillin-susceptible Staphylococcus aureus (MSSA range 0.25-0.5 pg/ml). The MICs of tea polyphenols ranged from 50 to 180 pg/ml for both the MSSA and the MRSA strains. The MICs of oxacillin for each of the 13 MRSA strains were reduced between 8- and 128-fold when these strains were coincubated with sub-MIC (<0.5 X MIC) levels of tea polyphenols, demonstrating that this combination was synergistic for all of the clinical MRSA isolates (Cho et al. 2008). 

Another important advance has been the application of PyMS with ANNs to discriminate between methicillin-resistant and methicillin-sensitive Staphylococcus aureusIn this study DFA and HCA showed that the major source of variation between the pyrolysis mass spectra of 15 methicillin-resistant (MRSA) and 22 methicillin-sensitive Staphylococcus aureus (MSSA) strains resulted from the phage group of the bacteria, rather than from their resistance or sensitivity to methicillin. By contrast, ANNs could recognize those aspects of the pyrolysis mass spectra that differentiated MRSA and MSSA strains. These results gave the first demonstration that the combination of PyMS with ANNs could provide a rapid and accurate antibiotic-susceptibility testing technique. 

The ferrocenyl bioconjugates of 6-aminopenicillanic acid 112 (Figure 3.7) have been evaluated for their antibacterial activity against S. aureus ATCC 29213 (MSSA, methicillin-susceptible Staphylococcus aureus), S. aureus ATCC 43300 (MRSA, methicillin-resistant Staphylococcus awrews), S. awrewsATCC 700787 (VRSA, vancomycin-resistant Staphylococcus aureus), and Staphylococcus epidermidis ATCC 12228 bacterial strains [86]. The minimum inhibitory concentration (MIC) of... 

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