• Acinetobacter baumannii : Evolution as an opportunistic nosocomial and successful pathogen worldwide
  • Hamid Mahmoodipour ,1,* Omid Mahmoodipour ,2 Maziar Mohammadi Niaei ,3
    1. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran
    2. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran
    3. Department of Nursing and Midwifery, Behbahan Branch, Islamic Azad University, Behbahan, Iran


  • Introduction: Gram-negative coccobacilli classified as Acinetobacter baumannii are important Gram-negative opportunistic bacterial pathogens that are responsible for 2–10% of all Gramnegative hospital infections(Joly-Guillou, 2005; Khadke et al., 2019). Acinetobacter baumannii infections have become an emerging health concern in hospitals across the world and are often associated with nosocomial infections with poorer clinical outcomes in patients with prolonged hospital stay(Nasr, 2020). Acinetobacter baumannii has been recognized as an agent of pneumonia, septicemia, meningitis, urinary tract and wound infections, and is associated with high mortality(Ayoub Moubareck & Hammoudi Halat, 2020). Acinetobacter baumannii is classified by the Infectious Diseases Society of America as one of the six most important multidrug-resistant (MDR) microorganisms in hospitals worldwide (Luısa et al., 2014). Indeed, the World Health Organization (WHO) has recently identified antimicrobial resistance as one of the three most important problems facing human health (Howard ,A. et al., 2012). The WHO has stated Acinetobacter baumannii to be one of the most serious ESKAPE organisms(Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa and Enterobacter spp) that have effectively escaped the effects of antibiotics(Mujawar et al., 2020). The Infectious Diseases Society of America (ISDA) stated Acinetobacter baumannii as one of the “red alert” pathogens that greatly threatens the utility of our current antibacterial armamentarium (Yadav et al., 2020). The aim of this mini-review summarises these recent advances, with particular focus on multidrug-resistance of Acinetobacter baumannii, and proposes new avenues of research.
  • Methods: This is a descriptive study. In this review summarise recent advances in knowledge concerning Acinetobacter baumannii, with particular focus on the multidrug-resistance of Acinetobacter baumannii pathogenicity, it should also be considered that the nature of the host (i.e. human patient) may also play a large part in the outcome of infections caused by Acinetobacter baumannii.
  • Results: The majority of Acinetobacter baumannii infections are caused by two main population clones with worldwide distribution. Infection outbreaks are often associated with multidrug resistance, including the recent emergence of strains resistant to all available antibiotics.
  • Conclusion: Acinetobacter baumannii virulence traits and pathogenic potential have mostly remained elusive. Acinetobacter has been known as a major cause of nosocomial infections worldwide and have shown a broad spectrum of resistance toward commonly used antimicrobial agents. Acinetobacter baumannii has evolved as a hospital pathogen, due in part to excessive and inappropriate use of antibiotics. Its transmission has been associated with war, natural disasters, and just about any other instance where one observes an influx in hospital trauma admissions and increased transfer of patients and staff from one hospital to the next. Patients infected with a clinical isolate of Acinetobacter baumannii have an average of $60,913 in additional patient charges due to the infection, and they stay in the hospital for an average of 13 days longer than a patient without an Acinetobacter baumannii infection. While Acinetobacter baumannii may not be particularly virulent, it can cause unnecessary disease and expense in the critically ill patients affected by it, and the transmission of such a pathogen should be limited. Measures to prevent the inter- and intrahospital transmission of Acinetobacter baumannii must be established in health care settings. Success in infection control has been attained by numerous others, and it can be attained by all if health care workers are educated about the proper way to manage MDR Acinetobacter baumannii. researchers understanding of the role of combination therapy for patients with multidrug or pandrug-resistant Acinetobacter baumannii infections is also critical. New therapeutics are clearly needed, and we as clinicians, microbiologists, and scientists must think broadly about our approach to antimicrobial drug development, as novel targets will no doubt provide the most reward for our afflicted patients. This review summarises these recent advances, with particular focus on Acinetobacter baumannii multidrug-resistance, and proposes new avenues of research.
  • Keywords: Acinetobacter baumannii, multidrug-resistant (MDR) microorganisms, hospital infections