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 (592 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
Infections caused by bacteria that show up as pink (negative) when treated by the gram-staining method.
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: Bacterial Infection, Gram-Negative; Gram-Negative Bacterial Infection; Gram Negative Bacterial Infections; Infection, Gram-Negative Bacterial; Infections, Gram-Negative Bacterial; Bacterial Infections, Gram-Negative.
Where it fits in the MeSH classification
- Broader topics
- Bacterial Infections
- Narrower topics
- Aliivibrio Infections; Anaplasmataceae Infections; Bacteroidaceae Infections; Bartonellaceae Infections; Bordetella Infections; Brucellosis; Burkholderia Infections; Campylobacter Infections; Chlamydiaceae Infections; Cytophagaceae Infections; Desulfovibrionaceae Infections; Enterobacteriaceae Infections; Flavobacteriaceae Infections; Foot Rot
Research landscape
PubMed indexes 433,043 records tagged with the MeSH heading “Gram-Negative Bacterial Infections” (counts retrieved 2026-10-29). 66,633 of them (15.4%) were published from 2020 onward, and the busiest period so far is through 1999 with 186,061 records.
Reviews account for 37,834 records (8.7%) and meta-analyses for 2,488. Randomized controlled trials number 6,307 (1.5%) as a share of all records on the topic. Randomized trials make up only a small share of this literature, so much of what is known comes from laboratory, observational or descriptive work.
Show the data
| Period | Records |
|---|---|
| through 1999 | 186,061 |
| 2000-2009 | 78,542 |
| 2010-2019 | 101,807 |
| 2020 onward | 66,633 |
Publication-type chart data
| Type | Records | Share |
|---|---|---|
| Reviews | 37,834 | 8.7% |
| Meta-analyses | 2,488 | 0.6% |
| Randomized controlled trials | 6,307 | 1.5% |
Method: PubMed query "Gram-Negative Bacterial Infections"[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 |
|---|---|---|---|---|
| Iran's Escherichia coli AMR Landscape (2010-2025): A One Health Systematic Review and Meta-Analysis | 2026 | Meta-analysis Design not recorded in structured metadata | 1 | cc by PMID 42830652 · DOI · PMC13635689 |
| A regulator of amino acid catabolism controls Acinetobacter baumannii gut colonization | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42733064 · DOI · PMC13572408 |
| Loss of Neutrophils and SLPI Reshapes Early Mucosal Inflammatory Responses During Intranasal Vaccination | 2026 | Research article Design not recorded in structured metadata | 1 | cc by PMID 42745636 · DOI · PMC13579227 |
Iran's Escherichia coli AMR Landscape (2010-2025): A One Health Systematic Review and Meta-Analysis [1]
Abstract reading summary — source excerpts
- Opening excerpt
- Escherichia coli (E.
- Closing excerpt
- Our study provides essential baseline data across human, animal, and environmental sectors in Iran, forming a basis for future One Health strategies and policy-making.
- 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 (240 words)
Escherichia coli (E. coli) has developed resistance to multiple antibiotic classes, complicating treatment in both human and veterinary medicine. This study assesses the prevalence of antimicrobial resistance and antimicrobial resistance genes in E. coli in Iran, within a One Health framework encompassing humans, animals, foods, and the environment. We systematically searched Scopus, Google Scholar, Magiran, PubMed, Scientific Information Database Library (SID), and Web of Science, using keywords related to AMR and Escherichia coli, restricting to English and Persian publications from 2010 to January 2025. The risk of bias was evaluated using the JBI checklist for prevalence studies. Pooled prevalence and 95% confidence intervals (CIs) were calculated for each antibiotic using random-effects models. A total of 368 studies were included in the meta-analysis. The highest resistance was observed in the Classes of Penicillins (71.7, 95% CI: 65.6-76.6) and the lowest for Fosfomycins (6.8, 95% CI: 5.2-8.5). Resistance to Ceftizoxime, Ertapenem, Streptomycin, Piperacillin-Tazobactam, and Colistin increased over time. Phenotypically, 47.2%, 20.2%, and 14.1% of E. coli isolates were identified as extended-spectrum β-lactamase-producing (ESBL), AmpC, and metallo-beta-lactamase (MBL) producing, respectively. Among ESBL-producing isolates, the prevalence of blaCTX-M, blaTEM, and blaSHV genes was 68.2%, 58.5%, and 24.4%, respectively. The high prevalence of AMR highlights the critical need for robust antimicrobial stewardship within a One Health framework to preserve antibiotic efficacy. Our study provides essential baseline data across human, animal, and environmental sectors in Iran, forming a basis for future One Health strategies and policy-making.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42830652 · DOI · PMC13635689
A regulator of amino acid catabolism controls Acinetobacter baumannii gut colonization [2]
Abstract reading summary — source excerpts
- Opening excerpt
- Asymptomatic gut colonization increases the risk of clinical infection and transmission by the multidrug-resistant pathogen Acinetobacter baumannii.
- Closing excerpt
- Together, these results suggest that pathogenic Acinetobacter species evolved AstR to regulate ornithine catabolism, which is required to compete with the microbiota during gut colonization.
- 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 (181 words)
Asymptomatic gut colonization increases the risk of clinical infection and transmission by the multidrug-resistant pathogen Acinetobacter baumannii. Ornithine utilization was shown to be critical for A. baumannii competition with the resident microbiota to persist in gut colonization, but the regulatory mechanisms and cues are unknown. Here, we identify a transcriptional regulator, AstR, that specifically activates the expression of the A. baumannii ornithine utilization operon astNOP. Phylogenetic analysis suggests that AstR was co-opted from the Acinetobacter arginine utilization ast(G)CADBE locus and is specialized to regulate ornithine utilization in A. baumannii. Reporter assays showed that astN promoter expression was activated by ornithine but inhibited by glutamate and other preferred amino acids. astN promoter expression was similarly activated by incubation with fecal samples from conventional mice but not germ-free mice, suggesting AstR-dependent activation of the astN promoter responds to intermicrobial competition for amino acids. Finally, AstR was required for A. baumannii to colonize the gut in a mouse model. Together, these results suggest that pathogenic Acinetobacter species evolved AstR to regulate ornithine catabolism, which is required to compete with the microbiota during gut colonization.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42733064 · DOI · PMC13572408
Loss of Neutrophils and SLPI Reshapes Early Mucosal Inflammatory Responses During Intranasal Vaccination [3]
Abstract reading summary — source excerpts
- Opening excerpt
- Vaccines delivered via the nasal route have attracted increasing attention for their capacity to engage the mucosal immune system at the primary site of pathogen entry.
- Closing excerpt
- pertussis and other pathogens.
- 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 (171 words)
Vaccines delivered via the nasal route have attracted increasing attention for their capacity to engage the mucosal immune system at the primary site of pathogen entry. However, the early innate mechanisms that shape local immune responses following nasal immunisation remain poorly defined. Here, we identified previously uncharacterised tissue-derived mediators induced during vaccination. Using an intranasally administered whole-cell pertussis (wP) vaccine that recapitulates key features of Bordetella pertussis infection and elicits long-lasting immunity, we show that nasal delivery triggers neutrophil recruitment along with a marked upregulation of secretory leukocyte protease inhibitor (SLPI). Employing SLPI- and neutrophil-deficient mouse models, we demonstrate that SLPI and neutrophils influence the production of key mediators associated with coagulation (PAI-1) and tissue remodelling (MMP-3 and MMP-9) within the airway. Notably, neutrophils also modulate early local total IgA release. Together, these findings suggest a coordinated and context-dependent interplay between cellular and soluble innate components that shape early mucosal immune responses. Furthermore, identified mediators may represent candidate biomarkers in the development of intranasal vaccines against B. pertussis and other pathogens.
Abstract reproduced from the open-access article under the recorded cc by licence; © the authors. PMID 42745636 · DOI · PMC13579227
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 Global Primary Antibiotic Resistance Rate of Helicobacter pylori in Recent 10 years: A Systematic Review and Meta-Analysis [4]
- Research article Eradication Therapy to Prevent Gastric Cancer in Helicobacterpylori-Positive Individuals: Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies [5]
- Research article Global prevalence of Helicobacter pylori antibiotic resistance among children in the world health organization regions between 2000 and 2023: a systematic review and meta-analysis [6]
- Research article Prevalence of Helicobacter pylori infection in China from 2014-2023: A systematic review and meta-analysis [7]
- Research article Nationwide trends and features of human salmonellosis outbreaks in China [8]
- Research article Evolving patterns of macrolide and fluoroquinolone resistance in Mycoplasma genitalium: an updated systematic review and meta-analysis [9]
References
- Dehghan A, Arabian M, Tahmasebi Z, Fakhri-Demeshghieh A, Baseri N, Mostafavi E, et al.. Iran's Escherichia coli AMR Landscape (2010-2025): A One Health Systematic Review and Meta-Analysis. . 2026. PMID 42830652 · DOI · PMC13635689
- Geary JH, Ren X, Bansah DA, Pham NTT, Acosta IC, Camilleri JM, et al.. A regulator of amino acid catabolism controls Acinetobacter baumannii gut colonization. . 2026. PMID 42733064 · DOI · PMC13572408
- Osiecka O, Tyshchenko M, Sinkevich I, Pocałuń N, Cichy J, Kwiecinski JM, et al.. Loss of Neutrophils and SLPI Reshapes Early Mucosal Inflammatory Responses During Intranasal Vaccination. . 2026. PMID 42745636 · DOI · PMC13579227
- Yu Y, Xue J, Lin F, Liu D, Zhang W, Ru S, et al.. Global Primary Antibiotic Resistance Rate of Helicobacter pylori in Recent 10 years: A Systematic Review and Meta-Analysis. Helicobacter. 2024. PMID 38898622 · DOI
- Ford AC, Yuan Y, Park JY, Forman D, Moayyedi P. Eradication Therapy to Prevent Gastric Cancer in Helicobacterpylori-Positive Individuals: Systematic Review and Meta-Analysis of Randomized Controlled Trials and Observational Studies. Gastroenterology. 2025. PMID 39824392 · DOI
- Salahi-Niri A, Nabavi-Rad A, Monaghan TM, Rokkas T, Doulberis M, Sadeghi A, et al.. Global prevalence of Helicobacter pylori antibiotic resistance among children in the world health organization regions between 2000 and 2023: a systematic review and meta-analysis. BMC Med. 2024. PMID 39710669 · DOI · PMC11664859
- Xie L, Liu GW, Liu YN, Li PY, Hu XN, He XY, et al.. Prevalence of Helicobacter pylori infection in China from 2014-2023: A systematic review and meta-analysis. World J Gastroenterol. 2024. PMID 39575409 · DOI · PMC11572641
- Wang Z, Zhou H, Liu Y, Huang C, Chen J, Siddique A, et al.. Nationwide trends and features of human salmonellosis outbreaks in China. Emerg Microbes Infect. 2024. PMID 38923510 · DOI · PMC11259058
- Chua TP, Vodstrcil LA, Murray GL, Plummer EL, Jensen JS, Unemo M, et al.. Evolving patterns of macrolide and fluoroquinolone resistance in Mycoplasma genitalium: an updated systematic review and meta-analysis. Lancet Microbe. 2025. PMID 40147462 · 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.