Author:
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Nowak, J.; Zander, E.; Stefanik, D.; Higgins, Paul G.; Roca, Ignasi; Vila Estapé, Jordi; McConnell, M. J.; Cisneros, José Miguel; Seifert, Harald; MagicBullet Working Group WP4
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Abstract:
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Objectives: To investigate the molecular epidemiology,
antimicrobial susceptibility and carbapenem resistance
determinants of Acinetobacter baumannii isolates from
respiratory tract samples of patients diagnosed with
ventilator-associated pneumonia (VAP) who were enrolled in the
MagicBullet clinical trial. Methods: A. baumannii isolates were
prospectively cultured from respiratory tract samples from 65
patients from 15 hospitals in Greece, Italy and Spain.
Susceptibility testing was performed by broth microdilution.
Carbapenem resistance determinants were identified by PCR and
sequencing. Molecular epidemiology was investigated using
rep-PCR (DiversiLab) and international clones (IC) were
identified using our in-house database. Results: Of 65 isolates,
all but two isolates (97%) were resistant to imipenem and these
were always associated with an acquired carbapenemase, OXA-23
(80%), OXA-40 (4.6%), OXA-58 (1.5%) or OXA-23/58 (1.5%).
Resistance to colistin was 47.7%. Twenty-two isolates were XDR,
and 20 isolates were pandrug-resistant (PDR). The majority of
isolates clustered with IC2 ( n = 54) with one major subtype
comprising isolates from 12 hospitals in the three countries,
which included 19 XDR and 16 PDR isolates. Conclusions:
Carbapenem resistance rates were very high in A. baumannii
recovered from patients with VAP. Almost half of the isolates
were colistin resistant, and 42 (64.6%) isolates were XDR or
PDR. Rep-PCR confirmed IC2 is the predominant clonal lineage in
Europe and suggests the presence of an epidemic XDR/PDR A.
baumannii clone that has spread in Greece, Italy and Spain.
These data highlight the difficulty in empirical treatment of
patients with A. baumannii VAP in centres with a high prevalence
of carbapenem-resistant A. baumannii . |