title: Clonal complexes 104, 109 and 113 playing a major role in the dissemination of OXA-carbapenemase-producing Acinetobacter baumannii in Southeast Brazil.
abstract: Carbapenem resistance among Acinetobacter baumannii strains isolated from clinical settings in Brazil has increased dramatically in the last 10 years due to the emergence and dissemination of OXA-type carbapenemase encoding genes. This study aimed to characterize the presence of carbapenem-hydrolyzing class D β-lactamases (CHDL)-encoding genes and clonal complexes playing a major role in the dissemination of OXA-carbapenemase-producing A. baumannii in Southeast Brazil. A total of 74 A. baumannii strains isolated from patients admitted to 4 hospitals in Southeast Brazil were analyzed. Molecular characterization of strains revealed that 67 strains carried blaOXA-23 (72%), blaOXA-143 (25%) or both genes (3%). PFGE analysis identified 12 PFGE clusters, grouping 26 pulsotypes. Two PFGE clusters were predominant, comprising more than 66% of OXA-producing A. baumannii isolates. Among 23 representative strains characterized by MLST-UO (Multilocus Sequence Typing Scheme - University of Oxford, http://pubmlst.org/abaumannii/), 14 different STs were identified, of which six were confirmed as novel sequence types (designated as STs 402-407). Most of these isolates belonged to clonal complexes CC104,CC109 or CC113, whereas three STs were singletons (ST339, 403 and 407). In conclusion, the presence of blaOXA-23- and blaOXA-143-like genes was not related to specific ST/CC, suggesting that the dissemination of OXA-carbapenemase-encoding genes may involve different STs, in which the spread of OXA-23-like is most likely due to mobile elements (i.e., plasmids). In this regard, CC104, CC109 and CC113 played a major role as predominant CDHL-carrying clones, instead of CC92, which was not identified.
authors.affiliation: Departamento de Análises Clínicas, Toxicológicas e Bromatológicas, Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo, Brazil.
authors.forename: Eduardo Carneiro
authors.initials: EC
authors.lastname: Clímaco
authors.forename: Milena Locci de
authors.initials: ML
authors.lastname: Oliveira
authors.forename: André
authors.initials: A
authors.lastname: Pitondo-Silva
authors.forename: Murilo Gomes
authors.initials: MG
authors.lastname: Oliveira
authors.forename: Micheli
authors.initials: M
authors.lastname: Medeiros
authors.forename: Nilton
authors.initials: N
authors.lastname: Lincopan
authors.forename: Ana Lúcia
authors.initials: AL
authors.lastname: da Costa Darini
mesh_terms: D000151:Acinetobacter Infections / Q000453:epidemiology / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000145:classification* / Q000187:drug effects / Q000201:enzymology / Q000235:genetics*; D000900:Anti-Bacterial Agents / Q000494:pharmacology; D001426:Bacterial Proteins / Q000235:genetics*; D001938:Brazil / Q000453:epidemiology; D006801:Humans; D017720:Molecular Epidemiology; D058885:Multilocus Sequence Typing; D018440:beta-Lactam Resistance / Q000235:genetics*; D001618:beta-Lactamases / Q000235:genetics*
chemical_list: D000900:Anti-Bacterial Agents; D001426:Bacterial Proteins; D001618:beta-Lactamases; C063912:carbapenemase
keywords: Acinetobacter baumannii; Carbapenem resistance; Molecular epidemiology; Multilocus sequence typing; PFGE, OXA carbapenemases