Analyses of the response of carbapenem-resistant Pseudomonas aeruginosa against monotherapy and combined therapy using quantum dots and proteomics.

Carbapenem-resistant P. aeruginosa (CRPA) has become a serious public health problem and the biofilm formation aggravates this problem. The study aimed to evaluate the occurrence of β-lactamases and quorum sensing (QS) genes in CRPA isolates, analyze production of biofilm, evaluate the response against meropenem (MPM) and∕or polymyxin B (POL B) and its association with azythromicin (AZT) using quantum dots (QDs) and proteomic analysis. Six CRPA isolates were analyzed. β-lactamases and QS genes were search using specific PCRs and were tested for biofilm production by quantitative technique. A CRPA isolate, containing blaKPC gene and biofilm-producing, was selected to assess its response to therapy using QDs and the MALDI-TOF. The β-lactamase detected was blaKPC in 66.7% of the isolates. All isolates were biofilm producers and carriers of the QS genes. QDs-MPM conjugates triggered the formation of biofilm and the association with AZT inhibited this effect. Proteomics analysis showed that treatments with MPM or POL B suppressed the expression of the transglycosylase protein, while combined therapy with AZT induced expression of the RpoN protein. Thus, this study shows that the use of fluorescence combined with the proteomics analysis was promising to understand how a CRPA strain reacts to antimicrobial treatment.