Realtids-PCR för påvisande av plasmidburen ampicillinresistens : Kartläggning av förekomst i vattenisolat från Helge Å, Kristianstad

Sammanfattning: The antibiotic class β-lactams include drugs such as penicillins, cephalosporines, carbapenems and monobactams which mechanism of action is to inhibit cell-wall synthesis. Bacteria have developed several mechanisms to counter β-lactams. Bacteria can defend themselves from antibiotics by releasing enzymes that attack the antibiotic compound itself by hydrolysis, target alteration or redox reactions. Presence of antibiotics can also trigger a downregulation of genes coding for antibiotic binding proteins, as well as upregulation of proteins that serves as channel and pump proteins that ensure no accumulation of antibiotics occurs in the cytosol. The aim with the study was to investigate the presence of three plasmid-mediated genes (blaFOX, blaCIT(CMY-2) and blaMOX) coding for ampicillin resistance (pAmpC) in water isolates sampled from Helge River, Kristianstad. The detection of genes was done according to a previous optimized protocol for Real-Time PCR with SYBR™Green chemistry (duplex blaCIT(CMY-2)/blaMOX and singleplex blaFOX). The method proved not to be robust for multiplex PCR, only the singelplex for the gene blaFOX could produce valid results. 30 of 96 isolates were deemed as positive for the gene, whereas 27 of 79 were considered clinical relevant. Among the 27 isolates, 16 also harbored other genes for resistance (13 blaCTX-M, 2 blaOXA, 1 blaTEM and 1 blaSHV). One isolate carried on three resistancegenes (blaFOX, blaCTX-M och blaTEM). A majority of the positive isolates, 20 out of 27, were sampled near the pumpstation. The findings indicate that Helge river might be a reservoir for dissemination of antibiotic resistance genes.