Comparative proteomic analysis of extracellular proteins expressed by various clonal types of Staphylococcus aureus and during planktonic growth and biofilm development

Abstract

Staphylococcus aureus is well known for its biofilm formation with rapid emergence of new clones circulating worldwide. The main objectives of the study were (1) to identify possible differences in protein expression among various and closely related clonal types of S. aureus, (2) to establish the differences in protein expression in terms of size of protein spots and its intensities between bacteria which are grown statically (biofilm formation) with that of under aeration and agitation, and (3) to compare the differences in protein expression as a function of time (in hours). In this study, we selected six clinical isolates comprising two similar (MRSA-527 and MRSA-524) and four different (MRSA-139, MSSA-12E, MSSA-22d, and MSSA-10E) types identified by spa typing, MLST and SCCmec typing. We performed 2D gel migration comparison. Also, two MRSA isolates (527 and 139) were selected to determine quantitative changes in the level of extracellular proteins at different biofilm growth time points of 12, 24, and 48 h. The study was done using a strategy that combines 2-DGE and LC-MS/MS analysis for absolute quantification and identification of the extracellular proteins. The 2DGE revealed that the proteomic profiles for the isolates belonging to the similar spa, MLST, and SCCmec types were still quite different. Among the extracellular proteins secreted at different time points of biofilm formation, significant changes in protein expression were observed at 48 h incubation as compared to the exponential growth at 12 h incubation. The main conclusion of the work is that the authors do observe differences among isolates, and growth conditions do influence the protein content at different time points of biofilm formation.

Topical adjuvants incompletely remove adherent Staphylococcus aureus from implant materials

“…Limitations of this study consist of the clinical translatability of the results, including biofilm maturation and heterogeneity, biofilm quantification methods, the size, and shape of the coupons as compared to prosthetics, the duration of treatment exposure, and the cytotoxicity of these topical adjuvants to healthy cells. Although it has been shown that mature biofilm can be established in vitro following 48 h incubation, clinical presentations of biofilm‐related joint infection generally consist of long‐established biofilm . However, the clinical application of adjuvant treatments as described here would be considered in the setting of acute infections.…”

Potential of proteomics to probe microbes

“…The most abundant P. acnes proteins were identified to be CAMP factors, and surface‐exposed dermatan sulfate adhesions [47]. The variation in protein expression of different clonal types of S. aureus at various stages of biofilm formation was determined by coupling 2D gel electrophoresis and LC‐MS/MS [48]. The differentially expressed proteins of Dunaliella salina , a halotolerant organism, were identified by MALDI‐TOF/TOF as molecular chaperones and proteins involved in respiration, photosynthesis, and amino acid synthesis [49].…”

Newly isolated lactic acid bacteria from silage targeting biofilms of foodborne pathogens during milk fermentation

“…The antagonistic properties of LAB seem to be attractive also for targeting pathogens in biofilm embedded forms [11][12][13][14]. Biofilm is a complex three-dimensional microbial consortium where bacteria are embedded in an extracellular matrix of organic polymers produced by bacteria themselves [15][16][17]. The matrix drastically reduces the susceptibility of bacteria to different outer stress factors [18] providing up to 1000-fold higher tolerance to antimicrobials of the biofilm-embedded cells compared to their planktonic counterparts [19][20][21][22].…”