title: MALDI-TOF MS as a Tool To Detect a Nosocomial Outbreak of Extended-Spectrum-β-Lactamase- and ArmA Methyltransferase-Producing Enterobacter cloacae Clinical Isolates in Algeria.
abstract: Enterobacter cloacae is among the most important pathogens responsible for nosocomial infections and outbreaks. In this study, 77 Enterobacter isolates were collected: 27 isolates from Algerian hospitals (in Constantine, Annaba, and Skikda) and 50 isolates from Marseille, France. All strains were identified by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS). Antibiotic susceptibility testing was performed by the disk diffusion method. PCR was used to detect extended-spectrum-beta-lactamase (ESBL)-encoding, fluoroquinolone resistance-encoding, and aminoglycoside-modifying enzyme (AME) genes. Epidemiological typing was performed using MALDI-TOF MS with data mining approaches, along with multilocus sequence typing (MLST). Sixty-eight isolates (27 from Algeria, 41 from Marseille) were identified by MALDI-TOF MS as E. cloacae. Resistance to antibiotics in the Algerian isolates was significantly higher than that in the strains from Marseille, especially for beta-lactams and aminoglycosides. Eighteen of the 27 Algerian isolates and 11 of the 41 Marseille isolates possessed at least one ESBL-encoding gene: blaCTX-M and/or blaTEM. AME genes were detected in 20 of the 27 Algerian isolates and 8 of the 41 Marseille isolates [ant(2″)-Ia, aac(6')-Ib-cr, aadA1, aadA2, and armA]. Conjugation experiments showed that armA was carried on a transferable plasmid. MALDI-TOF typing showed three separate clusters according to the geographical distribution and species level. An MLST-based phylogenetic tree showed a clade of 14 E. cloacae isolates from a urology unit clustering together in the MALDI-TOF dendrogram, suggesting the occurrence of an outbreak in this unit. In conclusion, the ability of MALDI-TOF to biotype strains was confirmed, and surveillance measures should be implemented, especially for Algerian patients hospitalized in France.
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France Laboratoire de Microbiologie et Biochimie Appliquée, Département de Biochimie, Faculté des Sciences, Université Badji Mokhtar, Annaba, Algeria.
authors.forename: Nour Chems el Houda
authors.initials: NC
authors.lastname: Khennouchi
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France Laboratoire de Biotechnologie des Molécules Bioactives et de la Physiopathologie Cellulaire (LBMBPC), Université El Hadj Lakhdar, Batna, Algeria.
authors.forename: Lotfi
authors.initials: L
authors.lastname: Loucif
authors.affiliation: Laboratoire de Microbiologie et Biochimie Appliquée, Département de Biochimie, Faculté des Sciences, Université Badji Mokhtar, Annaba, Algeria.
authors.forename: Nafissa
authors.initials: N
authors.lastname: Boutefnouchet
authors.affiliation: Etablissement Hospitalier Spécialisé d'Uro-Nephrologie, Daksi, Constantine, Algeria.
authors.forename: Hamoudi
authors.initials: H
authors.lastname: Allag
authors.affiliation: Unité de Recherche sur les Maladies Infectieuses et Tropicales Émergentes (URMITE), UM63, CNRS 7278, IRD 198, INSERM 1095, IHU Méditerranée Infection, Faculté de Médecine et de Pharmacie, Aix-Marseille-Université, Marseille, France jean-marc.rolain@univ-amu.fr.
authors.forename: Jean-Marc
authors.initials: JM
authors.lastname: Rolain
mesh_terms: D000462:Algeria / Q000453:epidemiology; D000900:Anti-Bacterial Agents / Q000627:therapeutic use; D003227:Conjugation, Genetic; D003428:Cross Infection / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D004196:Disease Outbreaks; D052978:Disk Diffusion Antimicrobial Tests; D024901:Drug Resistance, Multiple, Bacterial; D016972:Enterobacter cloacae / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D004756:Enterobacteriaceae Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology / Q000635:transmission; D005602:France / Q000453:epidemiology; D015870:Gene Expression; D006761:Hospitals; D006801:Humans; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D005810:Multigene Family; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D010957:Plasmids / Q000737:chemistry / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D008780:Methyltransferases; D001618:beta-Lactamases