Acinetobacter Infections

Classification and Clinical Significance

• Acinetobacter species are recognized as true pathogens in blood cultures, unlike common contaminants, according to the Infectious Diseases Society of America (IDSA) guidelines 1, 2, 3
• The IDSA/ASM guidelines specifically list Acinetobacter as a potential etiologic agent of bloodstream infections, not as a contaminant 1, 2, 3
• Acinetobacter is not typically considered a common blood culture contaminant, but rather a true pathogen that causes serious nosocomial infections, particularly in critically ill patients 1, 2, 3, 4
• Unlike common contaminants, Acinetobacter species are aerobic, glucose non-fermenting gram-negative coccobacilli that are widespread in the environment, according to Clinical Microbiology Reviews 5, 6

Blood Culture Contamination vs. True Bacteremia

• The 2018 IDSA/ASM guidelines define common blood culture contaminants, excluding Acinetobacter, and recommend that contamination rates should not exceed 3% 7, 8
• The 2024 ASM guidelines specifically define blood culture contaminants, excluding Acinetobacter, as coagulase-negative staphylococci, Corynebacterium spp., Bacillus spp., Micrococcus spp., certain alpha-hemolytic streptococci, and Cutibacterium acnes 5, 6