title: Clinical outcomes of hospital-acquired infection with Acinetobacter nosocomialis and Acinetobacter pittii.
abstract: The role of Acinetobacter nosocomialis and Acinetobacter pittii, which belong to the A. calcoaceticus-A. baumannii complex, in hospital-acquired infections is increasingly recognized. Here we describe a retrospective cohort study of hospital-acquired A. calcoaceticus-A. baumannii complex infections at a university hospital in Thailand. A total of 222 unique cases were identified between January 2010 and December 2011. The genomospecies of the A. calcoaceticus-A. baumannii complex isolates were classified as follows: A. baumannii, 197 (89%); A. nosocomialis, 18 (8%); and A. pittii, 7 (3%). All A. nosocomialis and A. pittii isolates were susceptible to imipenem and meropenem. The patients infected with A. nosocomialis and A. pittii had lower 30-day mortality than those infected with carbapenem-susceptible A. baumannii (P = 0.025) and carbapenem-resistant A. baumannii (P = 0.013). The factors influencing 30-day mortality were infection with non-baumannii A. calcoaceticus-A. baumannii complex (hazard ratio [HR], 0.12; 95% confidence interval [CI], 0.03 to 0.51; P = 0.004), infection with carbapenem-resistant A. baumannii (HR, 1.57; 95% CI, 0.89 to 2.79; P = 0.105), appropriate empirical antimicrobial therapy (HR, 0.38; 95% CI, 0.23 to 0.61; P < 0.001), and higher acute physiology and chronic health evaluation II (APACHE II) score (HR, 1.15; 95% CI, 1.10 to 1.19; P < 0.001). In Galleria mellonella assays, the survival rates were significantly higher for the larvae infected with A. nosocomialis or A. pittii than for those infected with either carbapenem-susceptible A. baumannii or carbapenem-resistant A. baumannii, but no differences in survival rates were observed between carbapenem-susceptible A. baumannii and carbapenem-resistant A. baumannii. These findings suggest intrinsic differences in virulence between non-baumannii A. calcoaceticus-A. baumannii complex species and A. baumannii but not between carbapenem-susceptible and resistant A. baumannii.
authors.affiliation: Division of Infectious Disease, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Sarunyou
authors.initials: S
authors.lastname: Chusri
authors.affiliation: Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Virasakdi
authors.initials: V
authors.lastname: Chongsuvivatwong
authors.affiliation: Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA.
authors.forename: Jesabel I
authors.initials: JI
authors.lastname: Rivera
authors.affiliation: Division of Infectious Disease, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Kachornsakdi
authors.initials: K
authors.lastname: Silpapojakul
authors.affiliation: Department of Biomedical Sciences, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Kamonnut
authors.initials: K
authors.lastname: Singkhamanan
authors.affiliation: Epidemiology Unit, Faculty of Medicine, Prince of Songkla University, Songkhla, Thailand.
authors.forename: Edward
authors.initials: E
authors.lastname: McNeil
authors.affiliation: Division of Infectious Diseases, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania, USA yod4@pitt.edu.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Doi
mesh_terms: D000151:Acinetobacter Infections / Q000188:drug therapy* / Q000382:microbiology / Q000401:mortality; D040981:Acinetobacter baumannii / Q000302:isolation & purification* / Q000472:pathogenicity; D000368:Aged; D000818:Animals; D000900:Anti-Bacterial Agents / Q000627:therapeutic use*; D015331:Cohort Studies; D003428:Cross Infection; D024881:Drug Resistance, Bacterial; D005260:Female; D006801:Humans; D015378:Imipenem / Q000627:therapeutic use*; D008297:Male; D000077731:Meropenem; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D009036:Moths / Q000382:microbiology; D012189:Retrospective Studies; D013845:Thienamycins / Q000627:therapeutic use*; D016896:Treatment Outcome
chemical_list: D000900:Anti-Bacterial Agents; D013845:Thienamycins; D015378:Imipenem; D000077731:Meropenem