Definition and research guide
This page combines a MeSH definition, publication statistics and selected research abstracts. It is a starting point for reading the literature, not a medical textbook or a systematic evidence review.
Content available: 3 complete abstracts (609 words), 9 references. Full article text is not stored or reproduced here; follow the PMID, DOI or PMC links to read the original sources and their access terms.
Definition
The presence of viable bacteria circulating in the blood. Fever, chills, tachycardia, and tachypnea are common acute manifestations of bacteremia. The majority of cases are seen in already hospitalized patients, most of whom have underlying diseases or procedures which render their bloodstreams susceptible to invasion.
Definition: NLM Medical Subject Headings (MeSH) scope note (Public domain (U.S. National Library of Medicine); attribution requested). View the MeSH record.
Also known as: Bacteremias.
Where it fits in the MeSH classification
- Broader topics
- Bacterial Infections; Sepsis
- Narrower topics
- Hemorrhagic Septicemia; Endotoxemia
- See also
- Endotoxemia
Research landscape
PubMed indexes 36,365 records tagged with the MeSH heading “Bacteremia” (counts retrieved 2026-10-29). 7,038 of them (19.4%) were published from 2020 onward, and the busiest period so far is 2010-2019 with 12,825 records.
Reviews account for 3,341 records (9.2%) and meta-analyses for 308. Randomized controlled trials number 849 (2.3%) as a share of all records on the topic.
Show the data
| Period | Records |
|---|---|
| through 1999 | 7,172 |
| 2000-2009 | 9,330 |
| 2010-2019 | 12,825 |
| 2020 onward | 7,038 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 3,341 | 9.2% |
| Meta-analyses | 308 | 0.8% |
| Randomized controlled trials | 849 | 2.3% |
Method: PubMed query "Bacteremia"[MeSH Terms] with publication-type and date filters, retrieved 2026-10-29.
Reading the evidence in infectious diseases
Infectious disease evidence combines microbiology, epidemiology and clinical trials. Laboratory studies identify pathogens and how they cause harm; surveillance and outbreak investigations describe who is affected and how infection spreads; trials establish whether treatments and vaccines work. Results depend on place and time, because pathogens evolve and resistance patterns and population immunity change. Check when and where the data were collected, how cases were defined and how up to date the evidence is.
Evidence from open-access studies
These open-access studies come from PubMed’s best-match results for this heading (papers whose main topic it is), ranked here by citation count, with one recent addition. Each abstract is reproduced in full under its recorded open licence so that you can read the authors’ own words. They illustrate the literature; they are not a systematic summary of it. Citation counts measure attention, not reliability or clinical benefit.
| Study / authors | Year | Source label / design | Europe PMC citations | Licence / source |
|---|---|---|---|---|
| Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia | 2026 | Randomized controlled trial Design not recorded in structured metadata | 10 | cc by PMID 42308484 · DOI · PMC7619232 |
| Vancomycin heteroresistance (hVISA) in MRSA links to treatment failure and supports a revised PAP-AUC threshold | 2025 | Research article Design not recorded in structured metadata | 9 | cc by PMID 41387691 · DOI · PMC12717272 |
| Vancomycin resistance predicts increased mortality in patients with Enterococcus faecium bloodstream infections: a six-year experience at a large tertiary care Italian hospital | 2026 | Research article Design not recorded in structured metadata | 4 | cc by PMID 41790115 · DOI · PMC13016866 |
Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia [1]
Abstract reading summary — source excerpts
- Opening excerpt
- BackgroundStaphylococcus aureus bacteremia is associated with high mortality.
- Closing excerpt
- ).
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (268 words)
BackgroundStaphylococcus aureus bacteremia is associated with high mortality. Whether cefazolin or an antistaphylococcal penicillin should be preferred for the treatment of methicillin-susceptible S. aureus bacteremia is unclear.MethodsIn an ongoing international Bayesian adaptive platform trial, we conducted an open-label, randomized comparison of cefazolin with an antistaphylococcal penicillin (flucloxacillin or cloxacillin) in adult patients with penicillin-resistant, methicillin-susceptible S. aureus bacteremia. The primary outcome, which was evaluated with a hierarchical Bayesian logistic-regression model, was death from any cause within 90 days after enrollment in the platform. We assessed the posterior probability of the noninferiority of cefazolin to flucloxacillin or cloxacillin (with the criterion for noninferiority prespecified as an adjusted odds ratio of ResultsThis domain of the ongoing trial was conducted between February 17, 2022, and August 7, 2024, by which time the criterion for noninferiority had been met. Mortality at 90 days among adults who could be evaluated was 15.0% (97 deaths among 645 patients) in the cefazolin group and 17.0% (109 deaths among 642 patients) in the antistaphylococcal-penicillin group (adjusted odds ratio, 0.81; 95% credible interval, 0.59 to 1.12; probability of noninferiority, 99.2%; probability of superiority, 89.8%). Acute kidney injury occurred in 92 of 660 patients (13.9%) in the cefazolin group, as compared with 127 of 648 (19.6%) in the antistaphylococcal-penicillin group (adjusted odds ratio, 0.67; 95% credible interval, 0.50 to 0.89; probability of superiority, 99.7%).ConclusionsIn patients with methicillin-susceptible S. aureus bacteremia, cefazolin was noninferior to flucloxacillin or cloxacillin with respect to 90-day mortality and was associated with a lower incidence of acute kidney injury. (Funded by the National Health and Medical Research Council and others; SNAP ClinicalTrials.gov number, NCT05137119.).
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42308484 · DOI · PMC7619232
Vancomycin heteroresistance (hVISA) in MRSA links to treatment failure and supports a revised PAP-AUC threshold [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Heteroresistance to vancomycin among methicillin-resistant Staphylococcus aureus (MRSA) remains a diagnostic and therapeutic problem in clinical microbiology.
- Closing excerpt
- These findings underscore the clinical relevance of hVISA, and support routine testing for heteroresistance to inform treatment decisions.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (194 words)
Heteroresistance to vancomycin among methicillin-resistant Staphylococcus aureus (MRSA) remains a diagnostic and therapeutic problem in clinical microbiology. In this prospective cohort study of 842 adult patients with MRSA bacteremia in S. Korea, we investigate the prevalence, risk factors, and clinical implications of the heteroresistant vancomycin-intermediate S. aureus (hVISA) phenotype. The hVISA phenotype is detected in 22% of cases. Multivariable regression analysis reveals strong positive associations between hVISA and hospital-acquired infection, prior anti-MRSA therapy, vancomycin exposure, and particularly vancomycin MIC (odds ratio 15.2 per 1 mg/L increase, p < 0.001). Strikingly, patients infected with hVISA strains have a lower 90-day mortality compared to those with fully susceptible strains (hazard ratio 0.66, p = 0.019), suggesting a possible trade-off between resistance and virulence. However, in hVISA strains treated with vancomycin, outcomes reverse: mortality more than doubled (HR 2.5, p < 0.001), bacteremia persisted longer, and relapse rates increased fivefold. Using maximally selected rank statistics, we identify a PAP-AUC threshold of 0.65 as the first clinically derived breakpoint predictive of mortality risk, providing an actionable definition of vancomycin heteroresistance. These findings underscore the clinical relevance of hVISA, and support routine testing for heteroresistance to inform treatment decisions.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41387691 · DOI · PMC12717272
Vancomycin resistance predicts increased mortality in patients with Enterococcus faecium bloodstream infections: a six-year experience at a large tertiary care Italian hospital [3]
Abstract reading summary — source excerpts
- Opening excerpt
- ObjectivesTo report on clinical outcomes associated with vancomycin-resistant Enterococcus faecium (VRE) Bloodstream infections (BSIs) observed during a 6-year period at a hospital from an area of high VRE endemicity.
- Closing excerpt
- faecium BSI.
- Interpretation limits
- Verbatim excerpts from the authors’ abstract; the closing excerpt may describe a finding, limitation or recommendation. Design, population, effect size and uncertainty have not been independently extracted or appraised. Read the complete abstract and linked paper before interpreting the findings.
Read complete abstract (147 words)
ObjectivesTo report on clinical outcomes associated with vancomycin-resistant Enterococcus faecium (VRE) Bloodstream infections (BSIs) observed during a 6-year period at a hospital from an area of high VRE endemicity.Material and methodsRetrospective study of patients with VRE and/or vancomycin-susceptible E. faecium (VSE) BSI in an Italian tertiary care hospital from January 2018 to December 2023.ResultsThe cohort included 116 VRE and 225 VSE BSIs. The baseline characteristics were comparable in both populations. Almost half VRE population (53/116, 46%) received no or ineffective empiric therapy against VRE. A targeted effective therapy was initiated with a mean delay of 2.2, ± 0.4 days in the VRE patients and of 1.2 ± 0.1 days (P ConclusionsE. faecium BSIs confirmed to be associated with high mortality rate, especially in fragile patients. Moreover, vancomycin resistance is an independent mortality factor. Further studies are needed to identify patients at higher risk for E. faecium BSI.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 41790115 · DOI · PMC13016866
Key reviews and meta-analyses
The most cited review-type papers among PubMed’s best-match results for this heading, listed with bibliographic details only. Follow the links for the full text and access terms.
- Research article The Effect of Molecular Rapid Diagnostic Testing on Clinical Outcomes in Bloodstream Infections: A Systematic Review and Meta-analysis [4]
- Research article Staphylococcus aureus bacteraemia mortality: a systematic review and meta-analysis [5]
- Research article Epidemiology of Escherichia coli Bacteremia: A Systematic Literature Review [6]
- Research article Periodontal health status and bacteraemia from daily oral activities: systematic review/meta-analysis [7]
- Research article Attributable mortality of central line associated bloodstream infection: systematic review and meta-analysis [8]
- Research article The diagnostic accuracy of procalcitonin for bacteraemia: a systematic review and meta-analysis [9]
References
- Staphylococcus aureus Network Adaptive Platform (SNAP) Trial Group, Lee TC, Barina LA, Walls G, Goodman AL, Yahav D, et al.. Cefazolin for Methicillin-Susceptible Staphylococcus aureus Bacteremia. . 2026. PMID 42308484 · DOI · PMC7619232
- Fatsis-Kavalopoulos N, Kim YK, Chong YP, Bae S, Lim SY, Kim YS, et al.. Vancomycin heteroresistance (hVISA) in MRSA links to treatment failure and supports a revised PAP-AUC threshold. . 2025. PMID 41387691 · DOI · PMC12717272
- Graziani L, Giani T, Farese A, Di Lauria N, Mantengoli E, Riccobono E, et al.. Vancomycin resistance predicts increased mortality in patients with Enterococcus faecium bloodstream infections: a six-year experience at a large tertiary care Italian hospital. . 2026. PMID 41790115 · DOI · PMC13016866
- Timbrook TT, Morton JB, McConeghy KW, Caffrey AR, Mylonakis E, LaPlante KL. The Effect of Molecular Rapid Diagnostic Testing on Clinical Outcomes in Bloodstream Infections: A Systematic Review and Meta-analysis. Clin Infect Dis. 2017. PMID 27678085 · DOI
- Bai AD, Lo CKL, Komorowski AS, Suresh M, Guo K, Garg A, et al.. Staphylococcus aureus bacteraemia mortality: a systematic review and meta-analysis. Clin Microbiol Infect. 2022. PMID 35339678 · DOI
- Bonten M, Johnson JR, van den Biggelaar AHJ, Georgalis L, Geurtsen J, de Palacios PI, et al.. Epidemiology of Escherichia coli Bacteremia: A Systematic Literature Review. Clin Infect Dis. 2021. PMID 32406495 · DOI
- Tomás I, Diz P, Tobías A, Scully C, Donos N. Periodontal health status and bacteraemia from daily oral activities: systematic review/meta-analysis. J Clin Periodontol. 2012. PMID 22092606 · DOI
- Ziegler MJ, Pellegrini DC, Safdar N. Attributable mortality of central line associated bloodstream infection: systematic review and meta-analysis. Infection. 2015. PMID 25331552 · DOI
- Hoeboer SH, van der Geest PJ, Nieboer D, Groeneveld AB. The diagnostic accuracy of procalcitonin for bacteraemia: a systematic review and meta-analysis. Clin Microbiol Infect. 2015. PMID 25726038 · DOI
About this article
- Sources
- NLM Medical Subject Headings (definition, synonyms); NCBI PubMed (counts, identifiers); Europe PMC (open-access abstracts and citation counts).
- Verification
- Every reference was resolved against PubMed on 2026-10-31; title, year and DOI matched.
- Review state
- automated source verified; no human expert review has been recorded yet.
- Version
- 1, last updated 2026-10-29.
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Evidence strength
EvidenceHelix's computed view of the study designs behind this topic: how common meta-analyses, randomized trials and reviews are, how recent the literature is, and a plain-language reading. It describes the design mix of the literature. It is not a quality appraisal of any study, and it is not medical advice.