Blood culture contamination: Difference between revisions

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Frequency of True Bacteremia	Organism	Gram Stain
Almost never true bacteremia (almost always contaminant)	Corynebacterium, except Corynebacterium jeikeium	Gram-positive bacillus
	Bacillus, except Bacillus anthracis	Gram-positive bacillus
	Cutibacterium acnes	Gram-positive bacillus
Sometimes true bacteremia	Micrococcus	Gram-positive cocci in groups
	Clostridium perfringens	Anaerobic Gram-positive bacillus
	Coagulase-negative staphylococci, except Staphylococcus lugdenensis	Gram-positive cocci in groups
	Viridans group streptococci	Gram-positive cocci in pairs and chains
	Lactobacillus	Gram-positive bacillus
	Nutritionally variant streptococci (Abiotrophia and Granulicatella)	Gram-positive cocci in pairs and chains
Usually true bacteremia	Enterococcus	Gram-positive cocci in pairs and chains
Usually true bacteremia	Aerococcus	Gram-positive cocci in pairs and chains
Always true bacteremia (or at least, always treated as such)	Staphylococcus aureus	Gram-positive cocci in groups
	Staphylococcus lugdenensis	Gram-positive cocci in groups
	Streptococcus pneumoniae	Gram-positive cocci in pairs and chains
	Escherichia coli and other Enterobacterales	Gram-negative bacilli
	Pseudomonas aeruginosa	Gram-negative bacilli
	Candida	Yeast

Coagulase-negative staphylococci are rarely significant (12%), but because they are so common (70-80% of all positive cultures), they are the most common cause of bacteremia

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+{| class="wikitable"
-= Blood culture contaminants =
+!Frequency of True Bacteremia
+!Organism
+!Gram Stain
+|-
+| rowspan="3" |'''Almost never''' true bacteremia (almost always contaminant)
+|[[Corynebacterium]], except [[Corynebacterium jeikeium]]
+|Gram-positive bacillus
+|-
+|[[Bacillus]], except [[Bacillus anthracis]]
+|Gram-positive bacillus
+|-
+|[[Cutibacterium acnes]]
+|Gram-positive bacillus
+|-
+| rowspan="6" |'''Sometimes''' true bacteremia
+|[[Micrococcus]]
+|Gram-positive cocci in groups
+|-
+|[[Clostridium perfringens]]
+|Anaerobic Gram-positive bacillus
+|-
+|[[Coagulase-negative staphylococci]], except [[Staphylococcus lugdenensis]]
+|Gram-positive cocci in groups
+|-
+|[[Viridans group streptococci]]
+|Gram-positive cocci in pairs and chains
+|-
+|[[Lactobacillus]]
+|Gram-positive bacillus
+|-
+|[[Nutritionally variant streptococci]] ([[Abiotrophia]] and [[Granulicatella]])
+|Gram-positive cocci in pairs and chains
+|-
+| rowspan="2" |'''Usually''' true bacteremia
+|[[Enterococcus]]
+|Gram-positive cocci in pairs and chains
+|-
+|[[Aerococcus]]
+|Gram-positive cocci in pairs and chains
+|-
+| rowspan="6" |'''Always''' true bacteremia (or at least, always treated as such)
+|[[Staphylococcus aureus]]
+|Gram-positive cocci in groups
+|-
+|[[Staphylococcus lugdenensis]]
+|Gram-positive cocci in groups
+|-
+|[[Streptococcus pneumoniae]]
+|Gram-positive cocci in pairs and chains
+|-
+|[[Escherichia coli]] and other [[Enterobacterales]]
+|Gram-negative bacilli
+|-
+|[[Pseudomonas aeruginosa]]
+|Gram-negative bacilli
+|-
+|[[Candida]]
+|Yeast
+|}
+* [[Coagulase-negative staphylococci]] are rarely significant (12%), but because they are so common (70-80% of all positive cultures), they are the most common cause of bacteremia
+== Further Reading ==
-* ''Never'' bacteremia
-** ''Corynebacterium''
+* Laboratory approaches to determining blood culture contamination rates: an ASM Laboratory Practices Subcommittee report. ''J Clin Microbiol''. 2023;62:e01028-23. doi: [https://doi.org/10.1128/jcm.01028-23 10.1128/jcm.01028-23]
-** ''Bacillus'', except ''B. anthracis''
-** ''Propionobacterium acnes''
+[[Category:Microbiology]]
-* ''Almost never'' bacteremia
-** ''Micrococcus''
-** ''Enterococcus''
-** ''Clostridium perfringens''
-** Coagulase-negative staphylococci
-* ''Always'' true bacteremia
-** ''Saphylococcus aureus''
-** ''Streptococcus pneumoniae''
-** ''Escherichia coli''
-** Enterobacteraciae
-** ''Pseudomonas aeruginosa''
-** ''Candida albicans''
-* Coagulase negative staphylococci are rarely significant (12%), but because they are so common (70-80% of all positive cultures), they are the most common cause of bacteremia.