Proteomics-based discrimination of differentially expressed proteins in antibiotic-sensitive and antibiotic-resistant Salmonella Typhimurium, Klebsiella pneumoniae, and Staphylococcus aureus.

This study was designed to compare the differentially expressed proteins between antibiotic-sensitive and antibiotic-resistant Salmonella Typhimurium, Klebsiella pneumonia, and Staphylococcus aureus. The susceptibilities of wild-type (WT), ciprofloxacin (CIP) and/or oxacillin (OXA)-induced, and clinically isolated resistant (CCARM) S. Typhimurium (ST, ST, and ST), K. pneumoniae (KP, KP, and KP), and S. aureus (SA, SA, SA, and SA) to antibiotics were determined using broth microdilution assay. ST was highly resistant to piperacillin (MIC > 512 μg/ml), KP was resistant to chloramphenicol (128 μg/ml) and norfloxacin (16 μg/ml), SA was resistant to fluoroquinolones (32 μg/ml), and SA was resistant to ceftriaxone (32 μg/ml). The protein profiles of antibiotic-sensitive and antibiotic-resistant strains were determined using 2-DE analysis followed by LC-MS/MS. The commonly expressed proteins of ST-ST, ST-ST, KP-KP, KP-KP, SA-SA, SA-SA, and SA-SA were 763, 677, 677, 469, 261, 259, and 226, respectively. The unique protein spots were observed 57 (6.5%), 80 (11.5%), and 68 (13.9%), respectively, for ST, KP, and SA. The highly up-regulated protein, PrsA (10-fold), was observed in ST resistant to ciprofloxacin (128-fold), levofloxacin (32-fold), norfloxacin (64-fold), and piperacillin (> 16-fold). The up-regulated proteins (YadC, FimA, and RplB) in KP resistant to chloramphenicol (> 32-fold), ciprofloxacin (32-fold), levofloxacin (6-fold), norfloxacin (128-fold), and sparfloxacin (64-fold). AcrB and RpoB were up-regulated in SA resistant to multiple antibiotics. The differentially expressed proteins were related to the antibiotic resistance of ST, ST, ST, KP, KP, KP, SA, SA, SA, and SA. The resistance-associated proteins could be useful biomarkers for detecting antibiotic-resistant pathogens.