Molecular characterization of genes encoding AmpC beta-lactamases in clinical isolates of Pseudomonas and Acinetobacter species

Abstract

Emergence of AmpC beta-lactamases in isolates of Pseudomonas and Acinetobacter species, is a threatening condition as they mediate resistance to a wide variety of β-lactam drugs, including α-methoxy-β-lactams, such as cefoxitin, narrow-, expanded-and broad-spectrum cephalosporins, aztreonam and are poorly inhibited by βlactam inhibitor combinations. The present study was conducted to determine the occurrence of blaampC genes in these pathogenic non-fermenters for their rapid and accurate detection. Monoplex PCR was done to detect blaampC genes in 40 non-duplicate clinical Pseudomonas and Acinetobacter isolates, that were found resistant to any of the third-generation cephalosporin and cefoxitin. Multiplex PCR assay was carried out to identify family-specific AmpC beta-lactamase genes within Pseudomonas and Acinetobacter spp. PCR detected blaampC in 43.24% of Pseudomonas and 33.33% of Acinetobacter isolates. Overall 42.50% of the total isolates were found to harbour blaampC genes by PCR. By multiplex PCR, total eight (20%) isolates yielded a positive amplicon with AmpCspecific primers. High prevalence of blaampC genes in cefoxitin-resistant isolates of Pseudomonas and Acinetobacter isolates emphasizes that molecular detection methods should be carried out to know the exact prevalence of beta-lactamases.

Antibiotic resistance in bacteria isolated from fish in Serbia

“…PCR was used to determine the presence of genes as follows: 16S rRNA methyltransferase according to the protocol described by Doi & Arakawa (2007), extended-spectrum ß-lactamase (TEM, SHV, CTX-M-1, CTX-M-9), OXA-1 and OXA-9 ß-lactamase, carbapenemases (OXA-23, OXA-24, OXA-40, OXA-58) which include metallo-ß-lactamase (VIM, IMP, SPM, GIM) according to the protocol described by Geyer & Hanson (2013), the carbapenemases (KPC) according to the protocol described by Shanmugam et al (2013), a metallo-ß-lactamase (NDM) according to the protocol of Fallah et al (2014), and AmpC-ß-lactamases -the AmpC group -according to the protocol of Jamali et al (2015), as well as single genes MOXM, CITM, ACCM, EBCM, FOXM, and DHAM according to the protocol of Perez-Perez & Hanson (2002), and finally, mcr-1 gene which encodes resistance to colistin according to the protocol described by Cavaco & Hendriksen (2015). Positive controls for all of the aforementioned genes were received from the Department for Biology and Pathology of Fish and Bees, Faculty of Veterinary Medicine, University of Zagreb and Scientific Veterinary Institute Novi Sad.…”