antibiotic resistance

Deep research

Generated by just research-trait; source: research/traits/physiology/antibiotic_resistance-deep-research-falcon.md

# TraitMech curation report: antibiotic resistance

## Record and scope summary

- **Trait:** antibiotic resistance
- **Identifier:** **`traitmech:000088`**
- **Category / kind / status:** PHYSIOLOGY / CLASS / REVIEWED
- **Parent:** `METPO:1000059`
- **Recommended operational meaning:** a microbial cell or population can **replicate at an antibiotic concentration that inhibits a defined susceptible comparator**, usually observed as an increased minimum inhibitory concentration (MIC) or categorical nonsusceptibility under a specified susceptibility-testing standard. MIC is the lowest concentration preventing visible replication; therefore, resistance is fundamentally a concentration-, medium-, incubation-, species-, and breakpoint-dependent phenotype rather than an unconditional property of a gene. (maeda2024laboratoryevolutionof pages 1-2)

The supplied definition—“a physiological capacity to grow in the presence of antibiotic concentrations that inhibit susceptible cells, mediated by efflux, target modification, drug inactivation, or reduced permeability”—is consistent with current mechanistic understanding. Canonical mechanisms additionally include **target replacement/protection** and **cell-envelope remodeling**. Resistance may be intrinsic or acquired by mutation or horizontal gene transfer. (maeda2024laboratoryevolutionof pages 1-2, zhu2022clinicalperspectiveof pages 4-5)

### Boundaries and nearby traits

1. **Tolerance is not resistance.** Tolerant populations survive longer exposure without necessarily having an increased MIC; time-kill measures are more appropriate than growth inhibition alone. (maeda2024laboratoryevolutionof pages 1-2, maeda2024laboratoryevolutionof pages 12-13)
2. **Persistence is not resistance.** Persistence is survival of a minority, typically non-growing or slow-growing subpopulation, without a stable population-wide MIC increase. It should be represented separately unless the graph explicitly models an evolutionary route from persistence to inherited resistance. (maeda2024laboratoryevolutionof pages 1-2, maeda2024laboratoryevolutionof pages 12-13)
3. **Heteroresistance is adjacent but distinct.** An isogenic population contains a resistant minority while the majority remains susceptible; routine MIC testing can report the isolate as susceptible. Population analysis profiling is the reference detection approach. Consequently, heteroresistance should not automatically instantiate the population-wide trait. (xu2025epidemiologymechanismsand pages 1-2)
4. **Multidrug resistance is a classification**, requiring resistance across multiple antimicrobial categories; it is not a separate molecular mechanism. A single resistance determinant can be narrow-spectrum or pleiotropic. (zhu2022clinicalperspectiveof pages 2-4)
5. **Biofilm-associated recalcitrance** can combine diffusion effects, altered physiology, tolerance, persistence, and inherited resistance. “Biofilm formation → antibiotic resistance” is too broad for unqualified curation.
6. **Antimicrobial resistance** is broader than antibiotic resistance because it includes antiviral, antifungal, and antiparasitic resistance. This graph should remain bacterial-antibiotic focused unless TraitMech intentionally uses the synonym broadly.

## Candidate nodes grouped by type

Identifiers below are deliberately conservative. Where an exact stable CURIE was not verified from the retrieved evidence, the node is left **label-only** rather than assigned a potentially incorrect identifier.

### Trait and assay nodes

- `traitmech:000088` — antibiotic resistance
- `METPO:1000059` — supplied parent trait
- minimum inhibitory concentration (MIC), label-only
- elevated MIC, label-only
- susceptible comparator, label-only
- antibiotic susceptibility testing, label-only
- clinical breakpoint, label-only
- population analysis profiling, label-only

### Environmental and experimental factors

- antibiotic exposure / selection pressure
- repeated antibiotic exposure
- subinhibitory antibiotic concentration
- inhibitory antibiotic concentration
- growth medium, inoculum, incubation time and temperature
- antibiotic combination or sequential/alternating treatment
- membrane permeabilizer
- metabolic inhibitor

Repeated exposure selects adaptive variants, whereas alternating drugs can slow evolution where collateral-sensitivity trade-offs apply. Laboratory evolution coupled to whole-genome sequencing and phenotyping is a current implementation for identifying such paths. (maeda2024laboratoryevolutionof pages 1-2, maeda2024laboratoryevolutionof pages 12-13, maeda2024laboratoryevolutionof pages 6-7)

### Genes, proteins, enzymes, transporters and complexes

- **Drug inactivation:** β-lactamases; ESBLs; AmpC; carbapenemases; NDM/VIM/IMP metallo-β-lactamases; OXA enzymes; aminoglycoside-modifying enzymes
- **Target replacement/remodeling:** `mecA`, `mecC`, PBP2a; `vanA`, `vanB`, `vanM`, VanHAX; D-Ala-D-Lac ligase
- **Target mutation/modification:** `gyrA`, `gyrB`, `parC`, `parE`; `erm`-family 23S-rRNA methyltransferases; 16S-rRNA methylases; `cfr`
- **Efflux:** AcrAB–TolC; AcrB; RND, MFS, MATE, SMR and ABC transporter families; `tetA`; `msrA`
- **Permeability:** OmpF; OprD/OprD2; porin loss or downregulation
- **Envelope remodeling:** `mcr-1`, `mcr-3`, `mcr-9`; MCR phosphoethanolamine transferases; EptA; PmrAB and PhoPQ regulatory systems
- **Evolution/dissemination:** plasmid, transposon and other mobile genetic element

### Chemicals, structures, cellular locations and processes

Showing the first 60 of 224 lines of findings; the linked file also carries the run's front matter and the prompt it was given — read the full report.