Investigation of a multiyear multiple critical care unit outbreak due to relatively drug-sensitive Acinetobacter baumannii: risk factors and attributable mortality.
From 1990 to 1993, an outbreak of respiratory Acinetobacter baumannii infection occurred in five intensive care units (ICUs) of a tertiary care center. A. baumannii was subsequently isolated from disinfected temperature probes and ventilator circuits. Pulsed-field gel electrophoresis suggested that a single strain accounted for 93% of patient isolates and 88% of environmental isolates. Univariate risk factors for A. baumannii acquisition were tracheostomy (P < .01), ventilation >3 days (P < .01), dialysis (P = .03), Stenotrophomonas maltophilia respiratory colonization (P = .02), parenteral nutrition (P = .05), and enteric feeding (P < .01). Logistic regression analysis showed duration of ventilation and enteric feeding to be independent risk factors. The outbreak strain was relatively antibiotic-susceptible, but the mortality attributable to respiratory A. baumannii acquisition was 23%. Only the APACHE II score was independently associated with increased mortality. Multifaceted control measures, including gas sterilization of temperature probes, terminated the outbreak.
Kaul
R
R
Department of Medicine, Toronto Hospital, University of Toronto, Canada.
Burt
J A
JA
Cork
L
L
Dedier
H
H
Garcia
M
M
Kennedy
C
C
Brunton
J
J
Krajden
M
M
Conly
J
J
D000151:Acinetobacter Infections / Q000188:drug therapy* / Q000453:epidemiology* / Q000401:mortality / Q000635:transmission; D000368:Aged; D016022:Case-Control Studies; D003428:Cross Infection / Q000382:microbiology; D003956:Dialysis / Q000009:adverse effects; D004196:Disease Outbreaks; D004352:Drug Resistance, Microbial; D016521:Electrophoresis, Gel, Pulsed-Field; D004750:Enteral Nutrition / Q000009:adverse effects; D005260:Female; D016905:Gram-Negative Bacterial Infections / Q000150:complications; D006801:Humans; D007362:Intensive Care Units; D008297:Male; D008826:Microbial Sensitivity Tests; D008875:Middle Aged; D010288:Parenteral Nutrition / Q000009:adverse effects; D012150:Polymorphism, Restriction Fragment Length; D012044:Regression Analysis; D012121:Respiration, Artificial / Q000009:adverse effects; D012141:Respiratory Tract Infections / Q000453:epidemiology / Q000635:transmission; D012307:Risk Factors; D014139:Tracheostomy / Q000009:adverse effects