Acinetobacter baumannii 2002-2008: increase of carbapenem-associated multiclass resistance in the United States.
The study consisted of data for 55,330 U.S. Acinetobacter baumannii isolates from The Surveillance Network(®) database for the period 2002-2008. Risk factors were time, age, sex, census region, location (Ward or ICU), and isolate source. Antimicrobial susceptibility data were available for carbapenems, cephalosporins, aminoglycosides, fluoroquinolones, and β-lactam/β-lactamase inhibitor combinations. Multiclass resistance was defined as nonsusceptibility to carbapenems and two or more additional classes. Odds of resistance were obtained using a logistic regression model with cubic splines. Carbapenem-associated multiclass resistance has had a 3.7-fold (95% confidence interval [CI] 3.4-4.3) increase from 20.6% in 2002 to 49.2% in 2008. Among blood isolates the increase was by 2.2 times (95% CI 1.7-2.9). Subjects <18 years old had significantly (p < 0.001) lower rates in 2002 (6.9%) than those 65 years or older (21.5%), but by 2008 this difference diminished as rates increased to 44.2% and 54.2%, respectively. A similar divergence was also observed between ICU and Ward, with no differences in 2002, whereas in 2008 ICU isolates had significantly higher rates (55.2%, 95% CI 53.6%-56.9%) than Ward isolates (45.6%, 95% CI 44.2%-47.0%). Over half of all A. baumannii-resistant isolates were carbapenem and multiclass resistant in 2008. Rates among subjects <18 years old have increased faster than those of the elderly, and in the ICU as compared to Ward.
Mera
Robertino M
RM
Department of Research Statistics, GlaxoSmithKline, Durham, North Carolina 27709, USA. robertino.mera@gsk.com
Miller
Linda A
LA
Amrine-Madsen
Heather
H
Sahm
Daniel F
DF
D000151:Acinetobacter Infections / Q000453:epidemiology* / Q000382:microbiology; D040981:Acinetobacter baumannii / Q000187:drug effects*; D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D015780:Carbapenems / Q000494:pharmacology*; D016208:Databases, Factual; D024901:Drug Resistance, Multiple, Bacterial; D006760:Hospitalization / Q000706:statistics & numerical data; D006801:Humans; D020407:Internet; D016015:Logistic Models; D008826:Microbial Sensitivity Tests; D011159:Population Surveillance / Q000379:methods; D015995:Prevalence; D012307:Risk Factors; D014481:United States / Q000453:epidemiology
D000900:Anti-Bacterial Agents; D015780:Carbapenems