title: Clinical and Pathophysiological Overview of Acinetobacter Infections: a Century of Challenges.
abstract: Acinetobacter is a complex genus, and historically, there has been confusion about the existence of multiple species. The species commonly cause nosocomial infections, predominantly aspiration pneumonia and catheter-associated bacteremia, but can also cause soft tissue and urinary tract infections. Community-acquired infections by Acinetobacter spp. are increasingly reported. Transmission of Acinetobacter and subsequent disease is facilitated by the organism's environmental tenacity, resistance to desiccation, and evasion of host immunity. The virulence properties demonstrated by Acinetobacter spp. primarily stem from evasion of rapid clearance by the innate immune system, effectively enabling high bacterial density that triggers lipopolysaccharide (LPS)-Toll-like receptor 4 (TLR4)-mediated sepsis. Capsular polysaccharide is a critical virulence factor that enables immune evasion, while LPS triggers septic shock. However, the primary driver of clinical outcome is antibiotic resistance. Administration of initially effective therapy is key to improving survival, reducing 30-day mortality threefold. Regrettably, due to the high frequency of this organism having an extreme drug resistance (XDR) phenotype, early initiation of effective therapy is a major clinical challenge. Given its high rate of antibiotic resistance and abysmal outcomes (up to 70% mortality rate from infections caused by XDR strains in some case series), new preventative and therapeutic options for Acinetobacter spp. are desperately needed.
authors.affiliation: Division of Infectious Diseases, Keck School of Medicine of the University of Southern California (USC), Los Angeles, California, USA Darren.Wong@med.usc.edu.
authors.forename: Darren
authors.initials: D
authors.lastname: Wong
authors.affiliation: Division of Infectious Diseases, Keck School of Medicine of the University of Southern California (USC), Los Angeles, California, USA.|Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, California, USA.
authors.forename: Travis B
authors.initials: TB
authors.lastname: Nielsen
authors.affiliation: Departments of Medicine, Pharmacology, and Molecular Biology and Microbiology, Louis Stokes Cleveland Department of Veterans Affairs Medical Center, Case Western Reserve University, Cleveland, Ohio, USA.
authors.forename: Robert A
authors.initials: RA
authors.lastname: Bonomo
authors.affiliation: Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, California, USA.
authors.forename: Paul
authors.initials: P
authors.lastname: Pantapalangkoor
authors.affiliation: Division of Infectious Diseases, Keck School of Medicine of the University of Southern California (USC), Los Angeles, California, USA.|Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, California, USA.
authors.forename: Brian
authors.initials: B
authors.lastname: Luna
authors.affiliation: Division of Infectious Diseases, Keck School of Medicine of the University of Southern California (USC), Los Angeles, California, USA.|Department of Molecular Microbiology and Immunology, Keck School of Medicine of USC, Los Angeles, California, USA.|Los Angeles County-USC (LAC+USC) Medical Center, Los Angeles, California, USA.
authors.forename: Brad
authors.initials: B
authors.lastname: Spellberg
mesh_terms: D000150:Acinetobacter / Q000187:drug effects / Q000378:metabolism / Q000472:pathogenicity*; D000151:Acinetobacter Infections / Q000188:drug therapy* / Q000276:immunology / Q000382:microbiology*; D000900:Anti-Bacterial Agents / Q000494:pharmacology / Q000627:therapeutic use; D002986:Clinical Trials as Topic; D017714:Community-Acquired Infections / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology; D003428:Cross Infection / Q000188:drug therapy / Q000276:immunology / Q000382:microbiology; D024901:Drug Resistance, Multiple, Bacterial / Q000187:drug effects; D006801:Humans; D061665:Time-to-Treatment; D037521:Virulence Factors / Q000276:immunology
chemical_list: D000900:Anti-Bacterial Agents; D037521:Virulence Factors
keywords: Acinetobacter; Acinetobacter baumannii; Acinetobacter calcoaceticus