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

@@ Line 1: / Line 1: @@
+{| class="wikitable"
-* '''Never''' bacteremia
+!Frequency of True Bacteremia
-** ''[[Corynebacterium]]''
+!Organism
-** ''[[Bacillus]]'', except ''B. anthracis''
+!Gram Stain
-** ''[[Propionobacterium acnes]]''
+|-
-* '''Almost never''' bacteremia
+| rowspan="3" |'''Almost never''' true bacteremia (almost always contaminant)
-** ''[[Micrococcus]]''
+|[[Corynebacterium]], except [[Corynebacterium jeikeium]]
-** ''[[Enterococcus]]''
+|Gram-positive bacillus
-** ''[[Clostridium perfringens]]''
+|-
-** [[Coagulase-negative staphylococci]]
+|[[Bacillus]], except [[Bacillus anthracis]]
-* '''Always''' true bacteremia
+|Gram-positive bacillus
-** ''[[Staphylococcus aureus]]''
+|-
-** ''[[Streptococcus pneumoniae]]''
+|[[Cutibacterium acnes]]
-** ''[[Escherichia coli]]''
+|Gram-positive bacillus
-** Enterobacteraciae
+|-
-** ''[[Pseudomonas aeruginosa]]''
+| rowspan="6" |'''Sometimes''' true bacteremia
-** ''[[Candida albicans]]''
+|[[Micrococcus]]
-* 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.
+|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 ==
+* 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]
 [[Category:Microbiology]]