What does bacteraemia mean?
Bacteraemia is the medical term for the presence of live bacteria in the bloodstream, detectable through blood culture. It is important to understand that bacteraemia itself is not necessarily an illness: it can be transient and symptomless — occurring briefly after brushing teeth, chewing, or dental procedures as oral bacteria slip into the circulation — and healthy immune systems typically clear it within minutes. When bacteria persist or multiply, however, bacteraemia can escalate into serious conditions such as sepsis, meningitis, or infective endocarditis, making it a critical finding in hospital medicine. Clinicians classify it by pattern and severity, distinguishing transient, intermittent, and continuous forms, and they treat organisms like Staphylococcus aureus in the blood with particular urgency. The word belongs to formal clinical vocabulary, appearing chiefly in medical journals, microbiology reports, and infection-control guidelines rather than casual conversation. It uses the British spelling bacteraemia, while American publications write bacteremia; both derive from Greek bakterion via Latinized scientific naming. Related terms include septicaemia, which denotes blood poisoning with systemic illness, and viraemia and fungaemia, its viral and fungal counterparts. Knowing this term helps readers interpret news about bloodstream infections, antimicrobial resistance, and hospital-acquired disease with greater precision.
nounThe presence of bacteria in the bloodstream. It may be transient and harmless, or it may lead to serious infection such as sepsis.
- The presence of viable bacteria in the bloodstream, whether symptomatic or asymptomatic; clinically distinguished from sepsis and from contaminated blood cultures.
"Blood cultures confirmed bacteraemia following the dental extraction."
"The patient developed a transient bacteraemia after a routine dental cleaning, but it resolved without treatment."
"Staphylococcus aureus bacteraemia is treated aggressively because of its high risk of endocarditis."
Rarely pluralized in practice; clinicians usually speak of episodes of bacteraemia rather than plural forms of the noun.
"The patient had two separate episodes of bacteraemia during her hospital stay."
Brushing your teeth too hard can cause a brief, harmless bout of bacteraemia — bacteria slipping into your blood for a few minutes before your immune system clears them.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of bacteraemia
The term bacteraemia was coined in the nineteenth century, during the rise of germ theory and clinical microbiology, when physicians first demonstrated that living bacteria could circulate in human blood. It combines the Greek-derived noun bacteria (from bakterion, meaning small rod) with the suffix -aemia, from the Greek haima for blood, a combining form already established in words like anaemia. The same -aemia suffix produced a family of related terms including septicaemia, toxaemia, and uraemia, all describing substances found in the blood.
Related word forms
How bacteraemia is actually used
A clinical/medical term used almost exclusively in professional healthcare contexts; not part of everyday vocabulary. British spelling is bacteraemia; American spelling is bacteremia. Clinicians distinguish transient (self-limiting), intermittent, and continuous bacteraemia, and note that positive blood cultures must be interpreted carefully to exclude contamination.
Easily confused with bacteraemia
Septicaemia is systemic illness caused by pathogens or their toxins in the blood, whereas bacteraemia refers simply to the presence of bacteria in the blood, which may cause no symptoms at all.
Viraemia is the presence of viruses (not bacteria) in the bloodstream.
Toxaemia is the presence of toxins rather than living bacteria in the blood.