Table 2.
Definitions used in or related to the blood culture process.
| Automated blood culture system | Blood culture system that uses equipment (an automated incubator) for incubation, agitation, and monitoring of blood culture bottles for microbial growth |
| Bacteremia | Presence of bacteria in the bloodstream |
| Biphasic blood culture system | Blood culture system in which a single bottle consists of a liquid broth phase and a solid agar phase; designed so the agar can be irrigated (and inoculated) with the broth medium |
| Blind subculture | Subculture performed from the blood culture bottle in the absence of visual signs of growth |
| Blood culture | Specimen of blood sampled through 1 venipuncture (possibly divided into multiple blood culture bottles) for the culture of micro-organisms |
| Blood culture broth | A liquid enrichment medium for the growth of bacteria used in the diagnosis of BSI. Usually contains peptides of animal origin and dextrose. |
| Bloodstream infection | Infection with the presence of bacteria in the blood |
| Bloodstream infection episode | A BSI episode is defined as (1) the initial recovery of a pathogen in a blood culture, (2) the recovery of a pathogen different from the initial pathogen ≥48 h after the recovery of the initial pathogen, or (3) the recovery of the same pathogen after at least a 14-day interval since the previous grown culture with this pathogen (5, 6) |
| Contamination | Growth of a micro-organisms in a blood culture that was introduced into the culture during blood culture collection or processing and that is not the cause of the suspected BSI |
| Culture medium | Substance used to facilitate growth of bacteria; can be solid (agar) or liquid (broth) |
| Endocarditis | Infection of the inner layer of the heart, the endocardium, often involving the heart valves |
| Fastidious organisms | Organisms that require special nutritional and incubation conditions for culture (e.g., addition of certain nutrients, incubation in carbon dioxide atmosphere) |
| HACEK organisms | A group of Gram-negative bacteria that are unusual causes of endocarditis; consists of the following species: Haemophilus parainfluenzae, Haemophilus aphrophilus, Actinobacillus actinomycetemcomitans, Cardiobacterium hominis, Eikenella corrodens, and Kingella kingae (7) |
| Manual blood culture bottle | Blood culture bottle that is designed for use in a manual blood culture system, i.e., without using automated equipment |
| Manual blood culture system | Blood culture system that processes blood culture bottles without the use of automated equipment |
| Non-fermenting Gram-negative organisms (non-fermenters) | Heterogenous group of Gram-negative bacilli that are aerobic and cannot metabolize carbohydrates through fermentation; mainly implicated in healthcare-associated infections and often resistant to many types of antibiotics |
| Subculture | A secondary culture of bacteria made from material derived from another culture, such as the blood-broth mixture of a blood culture bottle or the colonies on an agar plate |
| Terminal subculture | A subculture done at the end of the incubation period of blood culture bottles that failed to show signs of growth, to confirm the absence of growth of micro-organisms |