Case study: Denouement

Abstract

The aim of this study was to characterise the molecular drivers of multidrug resistance in Proteus mirabilis isolated from Algerian community and hospital patients.A total of 166 P. mirabilis isolates were collected from two hospitals and eight private laboratories from four cities (Khemis Miliana, Aïn Defla, Oran and Chlef) located in northwestern Algeria. All isolates were identified by matrix-assisted laser desorption/ionisation time-of-flight mass spectrometry (MALDI-TOF/MS). Antimicrobial susceptibility testing was performed by the disk diffusion and Etest methods. Genes encoding AmpC β-lactamases, extended-spectrum β-lactamases (ESBLs), quinolone resistance and aminoglycoside-modifying enzymes (AMEs) as well as plasmid replicon typing were characterised by PCR. Clonal relationships were also determined by enterobacterial repetitive intergenic consensus PCR (ERIC-PCR) typing and were compared with MALDI-TOF/MS proteomic typing.Of the 166 P. mirabilis isolates, 14 (8.4%) exhibited resistance to important antibiotics, including amoxicillin, amoxicillin/clavulanic acid, cefotaxime, gentamicin and ciprofloxacin, of which 4/14 (28.6%) had an ESBL genotype (blaCTX-M-2) and 10 (71.4%) had an AmpC/ESBL genotype (blaCMY-2/blaTEM-1). AME genes were detected in all isolates, including ant(2′′)-I, aac(3)-I, aac(6′)-Ib-cr and aac(3)-IV. The qnrA gene was identified in 13 isolates (7.8%). ERIC-PCR showed one predominant clone, with eight blaCMY-2-producing isolates from UHC Oran belonging to profile A clustering together in the MALDI-TOF/MS dendrogram.Here we report the first description of AME and plasmid-mediated quinolone resistance genes among ESBL- and/or AmpC β-lactamase-producing P. mirabilis isolates from community- and hospital-acquired infections in northwestern Algeria.