Direct detection of methicillin-resistant Staphylococcus aureus from blood cultures using an immunochromatographic immunoassay-based MRSA rapid kit for the detection of penicillin-binding protein 2a

2010 ◽  
Vol 67 (3) ◽  
pp. 301-303 ◽  
Author(s):  
Kyeong Seob Shin ◽  
Hyung Geun Song ◽  
Haejung Kim ◽  
Sangsun Yoon ◽  
Seung Bok Hong ◽  
...  
2013 ◽  
Vol 57 (10) ◽  
pp. 5005-5012 ◽  
Author(s):  
Andrew D. Berti ◽  
George Sakoulas ◽  
Victor Nizet ◽  
Ryan Tewhey ◽  
Warren E. Rose

ABSTRACTThe activity of daptomycin (DAP) against methicillin-resistantStaphylococcus aureus(MRSA) is enhanced in the presence of subinhibitory concentrations of antistaphylococcal β-lactam antibiotics by an undefined mechanism. Given the variability in the penicillin-binding protein (PBP)-binding profiles of different β-lactam antibiotics, the purpose of this study was to examine the relative enhancement of DAP activity against MRSA by different β-lactam antibiotics to determine if a specific PBP-binding profile is associated with the ability to enhance the anti-MRSA activity of DAP. We determined that both broad- and narrow-spectrum β-lactam antibiotics known to exhibit PBP1 binding demonstrated potent enhancement of DAP anti-MRSA activity, whereas β-lactam antibiotics with minimal PBP1 binding (cefoxitin, ceftriaxone, cefaclor, and cefotaxime) were less effective. We suspect that PBP1 disruption by β-lactam antibiotics affects pathways of cell division inS. aureusthat may be a compensatory response to DAP membrane insertion, resulting in DAP hypersusceptibility.


1996 ◽  
Vol 40 (9) ◽  
pp. 2075-2079 ◽  
Author(s):  
S Roychoudhury ◽  
R E Kaiser ◽  
D N Brems ◽  
W K Yeh

We investigated the enzymatic acylation of penicillin-binding protein 2a (PBP 2a) from methicillin-resistant Staphylococcus aureus by beta-lactams. Using a purified, soluble form of the protein (PBP 2a'), we observed beta-lactam-induced in vitro precipitation following first-order kinetics with respect to protein concentration. We used electrospray mass ionization spectrometry to show that the protein precipitate predominantly contained PBP 2a', with the beta-lactam bound to it in a 1:1 molar ratio. Using nitrocefin, a chromogenic beta-lactam, we confirmed the correlation between PBP 2a' precipitation and its beta-lactam-dependent enzymatic acylation by monitoring the absorbance associated with the precipitate. Finally, dissolving the precipitate in urea, we developed a simple in vitro chromogenic assay to monitor beta-lactam-dependent enzymatic acylation of PBP 2a'. This assay represents a significant improvement over the traditional radioactive penicillin-binding assay.


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