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Updated: Jul 14, 2026

Characterizing Multidrug Efflux Systems in Acinetobacter baumannii Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System
05:06

Characterizing Multidrug Efflux Systems in Acinetobacter baumannii Using an Efflux-Deficient Bacterial Strain and a Single-Copy Gene Expression System

Published on: January 5, 2024

Molecular findings and antibiotic-resistance in an outbreak of Acinetobacter baumannii in an intensive care unit

Benedetta Longo1, Annalisa Pantosti, Ida Luzzi

  • 1Dipartimento di Malattie Infettive, Parassitarie ed Immunomediate,Istituto Superiore di Sanità, Rome, Italy.

Annali Dell'Istituto Superiore Di Sanita
|May 31, 2007
PubMed

Insights

A multidrug-resistant Acinetobacter baumannii outbreak in an ICU was traced to a single clone found in patients and the environment. Eradication required comprehensive measures, and infected patients responded to combination therapy.

Area of Science:

  • Infectious Diseases
  • Clinical Microbiology
  • Hospital Epidemiology

Background:

  • Acinetobacter baumannii is a significant cause of hospital-acquired infections, particularly in intensive care units (ICUs).
  • Multidrug resistance, especially to carbapenems, is a growing concern with A. baumannii.
  • Environmental contamination plays a crucial role in the transmission of A. baumannii within healthcare settings.

Purpose of the Study:

  • To investigate the source and characteristics of an Acinetobacter baumannii outbreak in a hospital ICU.
  • To determine the genetic relatedness of patient and environmental isolates.
  • To evaluate the effectiveness of control measures and treatment strategies.

Main Methods:

  • Epidemiological investigation of a 14-patient outbreak.
  • Microbiological analysis of patient and environmental samples.
  • Antibiotic susceptibility testing.
  • Pulsed-field gel electrophoresis (PFGE) for molecular typing.

Main Results:

  • A single clone of multidrug-resistant Acinetobacter baumannii was identified in both patients and the hospital environment.
  • Bronchoalveolar lavage was the most frequent source of isolates from patients.
  • Environmental isolates exhibited similar antibiotic resistance patterns to patient isolates.
  • A broad control strategy including isolation, disinfection, and staff monitoring was implemented.

Conclusions:

  • Acinetobacter baumannii outbreaks in ICUs can be driven by a single, environmentally disseminated clone.
  • Effective control requires a multifaceted approach addressing patient, environmental, and staff factors.
  • Despite challenges, combined antibiotic therapy can successfully treat infected ICU patients.

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