title: Epidemic Dissemination of a Carbapenem-Resistant Acinetobacter baumannii Clone Carrying armA Two Years After Its First Isolation in an Italian Hospital.
abstract: This study describes the dissemination of a carbapenem-resistant Acinetobacter baumannii (CRAB) strain in a university hospital in Northeast Italy. Characterization of the outbreak strain was combined with a retrospective analysis of all CRAB isolates collected in the same hospital during the 5 years preceding the outbreak, with the aim of elucidating the origin of the epidemic spread. The outbreak strain was shown to belong to the International Clone II and carry the blaOXA-23gene, flanked by two ISAba1 sequences in opposite orientation (Tn2006 arrangement). The epidemic clone harbored also the blaOXA-66allele of the carbapenemase intrinsic to A. baumannii, the determinant of ArmA 16S rRNA methylase and a class 1 integron, with the aacA4, catB8, and aadA1 cassette array. Genotype analysis, performed by macrorestriction analysis and VRBA, revealed that isolates related to outbreak strain had been sporadically collected from inpatients in the 2 years preceding outbreak start. Carriage of blaOXA-66, armA, and the integron further supported relatedness of these isolates to the outbreak clone. Outbreak initially involved three medical wards, typically hosting elderly patients with a history of prolonged hospitalization. The study highlights the need to adopt strict infection control measures also when CRAB isolation appears to be a sporadic event.
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Annalisa
authors.initials: A
authors.lastname: Milan
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Linda
authors.initials: L
authors.lastname: Furlanis
authors.affiliation: 2 Department of Laboratory Medicine, Microbiology CS, Azienda Ospedaliero-Universitaria "Ospedali Riuniti," Trieste, Italy .
authors.forename: Franca
authors.initials: F
authors.lastname: Cian
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Raffaela
authors.initials: R
authors.lastname: Bressan
authors.affiliation: 3 Division of Infective Diseases, Azienda Ospedaliero-Universitaria "Ospedali Riuniti," Trieste, Italy .|4 Department of Medical, Surgical and Health Sciences, University of Trieste , Trieste, Italy .
authors.forename: Roberto
authors.initials: R
authors.lastname: Luzzati
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Cristina
authors.initials: C
authors.lastname: Lagatolla
authors.affiliation: 2 Department of Laboratory Medicine, Microbiology CS, Azienda Ospedaliero-Universitaria "Ospedali Riuniti," Trieste, Italy .
authors.forename: Maria Luisa
authors.initials: ML
authors.lastname: Deiana
authors.affiliation: 2 Department of Laboratory Medicine, Microbiology CS, Azienda Ospedaliero-Universitaria "Ospedali Riuniti," Trieste, Italy .
authors.forename: Anna
authors.initials: A
authors.lastname: Knezevich
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Enrico
authors.initials: E
authors.lastname: Tonin
authors.affiliation: 1 Department of Life Sciences, University of Trieste , Trieste, Italy .
authors.forename: Lucilla
authors.initials: L
authors.lastname: Dolzani
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000145:classification / Q000187:drug effects / Q000235:genetics* / Q000302:isolation & purification; D000483:Alleles; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics* / Q000378:metabolism; D015780:Carbapenems / Q000494:pharmacology; D002999:Clone Cells; D004196:Disease Outbreaks; D015964:Gene Expression Regulation, Bacterial; D006785:Hospitals, University; D006801:Humans; D032023:Integrons; D007558:Italy / Q000453:epidemiology; D008780:Methyltransferases / Q000235:genetics* / Q000378:metabolism; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D010802:Phylogeny; D010957:Plasmids / Q000737:chemistry / Q000145:classification / Q000378:metabolism*; D016133:Polymerase Chain Reaction; D012189:Retrospective Studies; D017422:Sequence Analysis, DNA; D018440:beta-Lactam Resistance / Q000235:genetics; D001618:beta-Lactamases / Q000235:genetics* / Q000378:metabolism
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D015780:Carbapenems; D008780:Methyltransferases; C047346:16S rRNA (adenine(1518)-N(6)-adenine(1519)-N(6))-dimethyltransferase; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Acinetobacter baumannii; ArmA; OXA-23; carbapenemase; integron; outbreak