Clinical and microbiological characteristics of OXA-23- and OXA-143-producing Acinetobacter baumannii in ICU patients at a teaching hospital, Brazil.
BACKGROUND
Carbapenem-resistant Acinetobacter baumannii (CRAb) is an important cause of nosocomial infections especially in intensive care units. This study aimed to assess clinical aspects and the genetic background of CRAb among ICU patients at a Brazilian teaching hospital.


METHODS
56 critically ill patients colonized or infected by CRAb, during ICU stay, were prospectively assessed. Based on imipenem MIC≥4μg/mL, 28 CRAB strains were screened for the presence of genes encoding metallo-β-lactamases and OXA-type β-lactamases. The blaOXA-type genes were characterized by PCR using primers targeting ISAba-1 or -3. Genetic diversity of blaOXA-positive strains was determined by ERIC-PCR analysis.


RESULTS
Patient's mean age (±SD) was 61 (±15.1), and 58.9% were male. Eighty-percent of the patients presented risk factors for CRAb colonization, mainly invasive devices (87.5%) and previous antibiotic therapy (77.6%). Thirty-three patients died during hospital stay (59.0%). Resistance to carbapenems was associated with a high prevalence of blaOXA-23 (51.2%) and/or blaOXA-143 (18.6%) genes. ERIC-PCR genotyping identified 10 clusters among OXA-producing CRAb. Three CRAb strains exhibited additional resistance to polymyxin B (MIC≥4μg/mL), whereas 10 CRAb strains showed tigecycline MICs>2μg/mL.


CONCLUSIONS
In this study, clonally unrelated OXA-123- and OXA-143-producing A. baumannii strains in ICU patients were strongly correlated to colonization with infected patients being associated with a poor outcome.
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil; Universidade Federal de Minas Gerais, Hospital das Clínicas Comissão de Controle de Infecção Hospitalar, Belo Horizonte, MG, Brazil. Electronic address: francellineves@gmail.com.
Francelli Cordeiro
FC
Neves
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil; Universidade Federal de Minas Gerais, Hospital das Clínicas Comissão de Controle de Infecção Hospitalar, Belo Horizonte, MG, Brazil.
Wanessa T
WT
Clemente
Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil; Universidade de São Paulo, Faculdade de Farmácia, Departamento de Análises Clínicas, São Paulo, SP, Brazil.
Nilton
N
Lincopan
Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil.
Isabela D
ID
Paião
Universidade de São Paulo, Instituto de Ciências Biomédicas, Departamento de Microbiologia, São Paulo, SP, Brazil.
Patrícia R
PR
Neves
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil; Universidade Federal de Minas Gerais, Hospital das Clínicas Comissão de Controle de Infecção Hospitalar, Belo Horizonte, MG, Brazil.
Roberta M
RM
Romanelli
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil.
Stella S S
SS
Lima
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil.
Luciene F
LF
Paiva
Universidade Federal de Minas Gerais, Faculdade de Medicina, Belo Horizonte, MG, Brazil.
Paulo Henrique O
PH
Mourão
Universidade Federal de Minas Gerais, Faculdade de Medicina, Departamento de Medicina Interna, Belo Horizonte, MG, Brazil.
Vandack A
VA
Nobre-Junior
D000151:Acinetobacter Infections / Q000382:microbiology*; D040981:Acinetobacter baumannii / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D001938:Brazil; D003428:Cross Infection / Q000382:microbiology*; D005260:Female; D005838:Genotype; D006784:Hospitals, Teaching; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D060885:Multiplex Polymerase Chain Reaction; D011446:Prospective Studies; D001618:beta-Lactamases / Q000096:biosynthesis* / Q000235:genetics
D000900:Anti-Bacterial Agents; C466679:beta-lactamase OXA-23; D001618:beta-Lactamases; C577374:beta-lactamase OXA-143, Acinetobacter baumannii
Acinetobacter baumannii; Carbapenem resistance; blaOXA-143; blaOXA-23