title: First characterisation of plasmid-mediated quinolone resistance-qnrS1 co-expressed bla CTX-M-15 and bla DHA-1 genes in clinical strain of Morganella morganii recovered from a Tunisian Intensive Care Unit.
abstract: OBJECTIVE
  Aim of this study was to show the emergence of the qnr genes among fluoroquinolone-resistant, AMPC and ESBL (extended-spectrum-beta-lactamase) co-producing Morganella morganii isolate.
  
  
  METHODS
  A multi resistant Morganella morganii SM12012 isolate was recovered from pus from a patient hospitalized in the intensive care unit at the Military hospital, Tunisia. Antibiotic susceptibility was tested with the agar disk diffusion method according to Clinical and Laboratory Standards Institute guidelines. ESBLs were detected using a standard double-disk synergy test. The characterization of beta-lactamases and associated resistance genes were performed by isoelectric focusing, polymerase chain reaction and nucleotide sequencing.
  
  
  RESULTS
  The antimicrobial susceptibility testing showed the high resistance to penicillins, cephalosporins (MICs: 64-512 μg/ml) and fluoroquinolones (MICs: 32-512 μg/ml). But M. morganii SM12012 isolate remained susceptible to carbapenems (MICs: 4-<0.25 μg/ml). The double-disk synergy test confirmed the phenotype of extended-spectrum β-lactamases (ESBLs). Three identical β-lactamases with pI values of 6.5, 7.8 and superior to 8.6 were detected after isoelectric focusing analysis. These β-lactamases genes can be successfully transferred by the conjugative plasmid. Molecular analysis demonstrated the co-production of bla (DHA-1), bla (CTX-M-15) and qnrS1 genes on the same plasmid. The detection of an associated chromosomal quinolone resistance revealed the presence of a parC mutation at codon 80 (Ser80-lle80).
  
  
  CONCLUSIONS
  This is the first report in Tunisia of nosocomial infection due to the production of CTX-M-15 and DHA-1 β-lactamases in M. morganii isolate with the association of quinolone plasmid resistance. The incidence of these strains invites continuous monitoring of such multidrug-resistant strains and the further study of their epidemiologic evolution.
authors.affiliation: Department of Biology, Laboratory of Biochemistry and Biotechnology, Faculty of Sciences of Tunis, Campus Universitaire, 2092 El-Manar II, Tunis, Tunisia.
authors.forename: S
authors.initials: S
authors.lastname: Mahrouki
authors.forename: A
authors.initials: A
authors.lastname: Bourouis
authors.forename: H
authors.initials: H
authors.lastname: Chihi
authors.forename: R
authors.initials: R
authors.lastname: Ouertani
authors.forename: M
authors.initials: M
authors.lastname: Ferjani
authors.forename: M B
authors.initials: MB
authors.lastname: Moussa
authors.forename: F
authors.initials: F
authors.lastname: Barguellil
authors.forename: O
authors.initials: O
authors.lastname: Belhadj
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D003428:Cross Infection / Q000453:epidemiology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial; D004756:Enterobacteriaceae Infections / Q000453:epidemiology / Q000382:microbiology*; D006801:Humans; D007362:Intensive Care Units; D007525:Isoelectric Focusing; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D020613:Morganella morganii / Q000187:drug effects* / Q000235:genetics / Q000302:isolation & purification; D010957:Plasmids; D016133:Polymerase Chain Reaction; D015363:Quinolones / Q000494:pharmacology*; D017422:Sequence Analysis, DNA; D013492:Suppuration / Q000382:microbiology; D014416:Tunisia / Q000453:epidemiology; D001618:beta-Lactamases / Q000235:genetics; D047090:beta-Lactams / Q000494:pharmacology*
chemical_list: D000900:Anti-Bacterial Agents; D015363:Quinolones; D047090:beta-Lactams; D001618:beta-Lactamases