# blaKPC-2 (Klebsiella pneumoniae Carbapenemase): Serine Beta-Lactamase Catalytic Mechanism


## Key Takeaways

- **Mechanism of Resistance:** KPC-2 is a class A serine β-lactamase that hydrolyzes the β-lactam ring of antibiotics, including penicillins, cephalosporins, monobactams, and critically, carbapenems, rendering them ineffective against bacterial cell wall synthesis.
- **Genetic Dissemination:** The *blaKPC-2* gene is predominantly plasmid-borne, often within the Tn4401 transposon, facilitating rapid horizontal gene transfer between Gram-negative pathogens like *Klebsiella pneumoniae*, *E. coli*, and *Pseudomonas aeruginosa*.
- **Structural Basis for Broad Spectrum:** The enzyme possesses a relatively open active site and a flexible Ω-loop, allowing it to accommodate and hydrolyze bulky carbapenem substrates, a characteristic not shared by many other class A β-lactamases.
- **Clinical Impact and Treatment Challenges:** Infections caused by KPC-2 producers are associated with high mortality; treatment options are limited and include ceftazidime-avibactam, meropenem-vaborbactam, and cefiderocol, though resistance to these agents can emerge through specific mutations (e.g., D179Y in the Ω-loop).
- **Diagnostic Significance:** Molecular detection of the *blaKPC-2* gene via PCR or whole-genome sequencing is crucial for accurate identification, as phenotypic resistance profiles can vary, and specialized tests like the Carba NP test may be required.

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## Executive Summary & Key Metadata

The gene **blaKPC-2** encodes the *Klebsiella pneumoniae* carbapenemase-2 (KPC-2), a class A serine β-lactamase that hydrolyzes a broad spectrum of β-lactam antibiotics, including penicillins, cephalosporins, monobactams, and critically, the carbapenem class (imipenem, meropenem, ertapenem). This enzyme is the archetypal member of the KPC family, which has disseminated globally among Gram-negative pathogens, primarily *Klebsiella pneumoniae*, but also *Escherichia coli*, *[Pseudomonas aeruginosa](/knowledge/bacteria/gram-negative/pseudomonas-aeruginosa-multidrug-resistance-biofilms)*, *Enterobacter* spp., and *Citrobacter* spp. [1, 2, 3, 4]. The clinical impact of KPC-2 is profound: infections caused by KPC-producing organisms are associated with high mortality rates, prolonged hospitalizations, and substantial economic burden [5, 6, 7]. The gene is typically harbored on transmissible plasmids, often within the Tn4401 transposon, facilitating its rapid inter- and intra-species dissemination [8, 9, 10, 11].

| **Attribute** | **Detail** |
| :--- | :--- |
| **HGNC Symbol** | blaKPC-2 (bacterial gene nomenclature; not a human gene) |
| **UniProt Accession** | Q9F663 |
| **Representative PDB ID** | 2O5V (KPC-2 apo-structure); 2OV5 (KPC-2 with inhibitor) |
| **Chromosomal Locus** | Typically plasmid-borne (e.g., IncFII, IncN, IncI2); rarely chromosomal. Located within transposon Tn4401. |
| **Primary Molecular Function** | Serine β-lactamase; hydrolysis of β-lactam ring of penicillins, cephalosporins, carbapenems, and monobactams. |
| **Disease & Pathology Associations** | Carbapenem-resistant Enterobacterales (CRE) infections; bacteremia, pneumonia, urinary tract infections, intra-abdominal abscesses; high mortality in immunocompromised and ICU patients. |

## 1. Genomic Locus, Chromosomal Organization & Isoforms

### 1.1 Gene Structure and Genetic Context

The blaKPC-2 gene is a 893-bp open reading frame (ORF) encoding a 293-amino-acid pre-protein, which includes a 22-amino-acid signal peptide that is cleaved to yield the mature 271-amino-acid enzyme. The gene is almost exclusively associated with the Tn3-family transposon **Tn4401**, which provides the mobile genetic context for its dissemination [10, 12]. Tn4401 is a ~10-kb element that carries the blaKPC-2 gene along with transposase (tnpA), resolvase (tnpR), and a mercury resistance operon in some variants. The transposon is typically inserted into conjugative plasmids, most commonly of the IncFIIK group (e.g., pKpQIL), but also IncN, IncI2, and IncX3 types [3, 8, 13, 14].

The genetic environment of blaKPC-2 is critical for its expression. The gene is preceded by a promoter region that is subject to variation. The most common promoter configuration is the **P1 promoter**, located upstream of the transposase gene, which drives high-level expression. However, deletions in the promoter region, such as those described in blaKPC-2a, blaKPC-2b, and blaKPC-2c variants, can alter expression levels and subsequently affect the minimum inhibitory concentrations (MICs) of β-lactams [15]. These promoter deletions are associated with reduced susceptibility to ceftazidime-avibactam (CAZ-AVI) and other β-lactam/β-lactamase inhibitor combinations, as lower enzyme production can be overwhelmed by the inhibitor in some contexts, but paradoxically, high expression can lead to resistance [15, 16].

### 1.2 Plasmid Localization and Horizontal Gene Transfer

The plasmid-borne nature of blaKPC-2 is a primary driver of its epidemiology. Unlike chromosomal resistance mutations, plasmid-encoded carbapenemases can be transferred horizontally between bacterial strains and species, leading to the rapid spread of resistance within and between hospitals [8, 9, 11]. Studies have demonstrated the interspecies transfer of blaKPC-2 within a single patient, where the gene moved from *K. pneumoniae* to *E. coli* and *Enterobacter cloacae* [11]. The IncFIIK34 plasmid, a specific variant, has been identified as a key vector for the global emergence of carbapenem-resistant hypervirulent *K. pneumoniae* (CR-hvKp), highlighting the convergence of resistance and virulence determinants on the same mobile element [13].

### 1.3 Isoforms and Variants

The KPC family comprises numerous variants (KPC-2 through KPC-50+), which differ by single or multiple amino acid substitutions. KPC-2 is the parent enzyme, and KPC-3 differs by a single amino acid substitution (H272Y). These variants exhibit subtle differences in substrate specificity and inhibitor susceptibility. For instance, KPC-3 is often associated with higher-level resistance to ceftazidime-avibactam when combined with specific mutations [1, 17]. The diversity of KPC variants is a result of ongoing evolution under antibiotic pressure, particularly from the use of CAZ-AVI [16, 17]. The blaKPC-2 gene itself does not undergo alternative splicing, as it is a prokaryotic gene; however, the term "isoform" in this context refers to the protein variants produced by different blaKPC alleles.

## 2. 3D Protein Domain Architecture & Structural Biology

### 2.1 Overall Fold and Domain Organization

KPC-2 is a monomeric, globular protein belonging to the class A β-lactamase family. Its three-dimensional structure, solved by X-ray crystallography (PDB: 2O5V), reveals a characteristic two-domain architecture:

1.  **α/β Domain (N-terminal):** This domain comprises a central five-stranded β-sheet surrounded by α-helices. It forms the structural core of the enzyme and contributes to the overall stability of the protein.
2.  **All-α Domain (C-terminal):** This domain is composed entirely of α-helices and forms one wall of the active-site cleft.

The active site is located at the interface between these two domains, forming a deep groove on the enzyme's surface. The catalytic machinery is centered on a conserved **Ser70** residue (using the standard class A β-lactamase numbering scheme, which is based on the ABL (Ambler) numbering). This serine acts as the nucleophile in the acylation step of β-lactam hydrolysis.

### 2.2 Catalytic Site and Key Residues

The catalytic mechanism of KPC-2 is characteristic of serine β-lactamases and involves a conserved set of residues:

- **Ser70 (Nucleophile):** The hydroxyl group of Ser70 attacks the carbonyl carbon of the β-lactam ring, forming a covalent acyl-enzyme intermediate.
- **Lys73 (General Base):** This residue acts as a general base, deprotonating the Ser70 hydroxyl group to enhance its nucleophilicity. It also plays a role in the deacylation step.
- **Ser130 (Oxyanion Hole Stabilizer):** Ser130, along with the backbone amide groups of Ser70 and Thr237, forms the oxyanion hole. This stabilizes the negative charge that develops on the carbonyl oxygen of the β-lactam during the transition state.
- **Glu166 (General Base for Deacylation):** In the deacylation step, a water molecule is activated by Glu166, which then attacks the acyl-enzyme intermediate, leading to the release of the hydrolyzed product and regeneration of the free enzyme.
- **Asn170:** This residue is part of the conserved SDN loop and helps to orient Glu166 and the catalytic water molecule.
- **Thr237:** Located in the Ω-loop, Thr237 contributes to the oxyanion hole and influences substrate specificity, particularly for carbapenems.
- **Cys238 and Cys69:** These two cysteine residues form a disulfide bond that stabilizes the overall [protein structure](/knowledge/bioinformatics/protein-structure-biophysical-levels-folding), particularly the Ω-loop region.

The **Ω-loop** (residues 161-179) is a critical structural element that forms one side of the active site. It contains Glu166 and Asn170 and is essential for the deacylation step. Mutations in this loop, such as the D179Y substitution, can alter the enzyme's activity and inhibitor profile, often leading to resistance to CAZ-AVI [1, 17].

### 2.3 Substrate Binding and Hydrolysis Mechanism

The catalytic cycle of KPC-2 can be divided into two main steps:

1.  **Acylation:** The β-lactam substrate binds in the active site, with its carbonyl group positioned in the oxyanion hole. The catalytic Ser70, activated by Lys73, performs a nucleophilic attack on the carbonyl carbon, opening the β-lactam ring and forming a covalent acyl-enzyme intermediate.
2.  **Deacylation:** A water molecule, activated by Glu166, attacks the acyl-enzyme intermediate. This leads to the hydrolysis of the ester bond, releasing the ring-opened, inactive β-lactam product and regenerating the active enzyme.

KPC-2 is notable for its broad substrate profile, which includes carbapenems. The ability to hydrolyze carbapenems is attributed to the relatively open active site and the flexibility of the Ω-loop, which allows the bulky carbapenem side chains to be accommodated. This is in contrast to many other class A β-lactamases (e.g., TEM and SHV), which have narrower active sites and cannot efficiently hydrolyze carbapenems.

### 2.4 Interactive 3D Visualizer

To explore the three-dimensional structure of KPC-2, including its active site residues and domain architecture, use the interactive visualizer below. This tool allows you to rotate the molecule, zoom into specific regions, and highlight key amino acids.

[Interactive 3D Protein Visualizer: Load blaKPC-2 (PDB: 2O5V)](/tools/protein-structure-viewer?source=direct&pdbId=2O5V)

## 3. Cellular Signaling Pathways & Molecular Function

### 3.1 Molecular Function: β-Lactam Hydrolysis

The primary and sole known molecular function of KPC-2 is the hydrolysis of β-lactam antibiotics. This is a direct enzymatic activity that does not involve complex cellular signaling cascades. The enzyme is secreted into the periplasmic space of Gram-negative bacteria, where it encounters and inactivates β-lactam molecules that have diffused through the outer membrane porins. The hydrolysis of the β-lactam ring renders the antibiotic ineffective, as it can no longer bind to and inhibit its target, the penicillin-binding proteins (PBPs) involved in cell wall synthesis.

### 3.2 Interaction with the Bacterial Cell Envelope

The function of KPC-2 is intimately linked to the structure of the bacterial cell envelope. In Gram-negative bacteria, the outer membrane acts as a permeability barrier, limiting the entry of antibiotics. KPC-2, being a periplasmic enzyme, is strategically located to intercept antibiotics that have successfully traversed the outer membrane. The efficiency of this "periplasmic barrier" is influenced by:

- **Porin Expression:** Reduced expression of outer membrane porins (e.g., OmpK35, OmpK36) decreases the rate of antibiotic influx, giving KPC-2 more time to hydrolyze the drug. This synergistic effect is a common mechanism of high-level carbapenem resistance [1, 2].
- **Efflux Pumps:** Overexpression of efflux pumps, such as AcrAB-TolC, can actively extrude antibiotics from the periplasm, further reducing the intracellular concentration of the drug and enhancing the protective effect of KPC-2 [15].

### 3.3 Protein-Protein Interactions and Regulatory Networks

KPC-2 does not participate in classical signal transduction pathways. However, its expression and activity are subject to regulatory control at the transcriptional and post-transcriptional levels. The gene is constitutively expressed from its promoter, but the level of expression can be modulated by:

- **Promoter Mutations:** As mentioned earlier, deletions or point mutations in the promoter region can alter transcription levels [15].
- **Copy Number:** The copy number of the plasmid carrying blaKPC-2 can influence gene dosage and thus enzyme production. High-copy-number plasmids can lead to increased KPC-2 expression and higher MICs.
- **Global Regulators:** The expression of blaKPC-2 can be influenced by global stress response regulators, such as the two-component systems involved in envelope stress response (e.g., CpxAR, BaeSR). These systems can sense the presence of cell wall-damaging agents and upregulate resistance mechanisms, potentially including β-lactamase expression.

### 3.4 Interaction with the Host Immune System

While KPC-2 does not directly interact with host immune cells, its presence has indirect effects on the host-pathogen interaction. By conferring resistance to β-lactams, KPC-2 allows the bacterium to survive antibiotic therapy, leading to persistent infection and a prolonged inflammatory response. This can result in severe tissue damage and sepsis. Furthermore, the acquisition of blaKPC-2 by hypervirulent strains of *K. pneumoniae* creates "superbugs" that combine high virulence with extensive drug resistance, leading to infections with exceptionally high mortality rates [1, 3, 4, 13].

### 3.5 Interaction Networks

KPC-2 does not have a well-defined protein-protein interaction network in the traditional sense. Its function is primarily enzymatic and dependent on its localization in the periplasm. However, it can be considered part of a larger "resistome" network, where multiple resistance mechanisms (e.g., other β-lactamases, porin mutations, efflux pumps) act in concert to provide high-level resistance. For example, the co-production of KPC-2 with NDM-1 or OXA-48-like carbapenemases is increasingly reported and can lead to resistance to almost all available β-lactams, including novel combinations like CAZ-AVI [4, 5, 6, 14].

## 4. Pathogenic Hotspot Mutations & Clinical Differentials

### 4.1 Mutations Affecting Substrate Specificity and Inhibitor Susceptibility

The evolution of KPC-2 under clinical antibiotic pressure has led to the emergence of numerous variants with altered properties. These mutations are often located in or near the active site and can affect substrate affinity, catalytic efficiency, and susceptibility to β-lactamase inhibitors.

| **Mutation** | **Variant** | **Effect on Phenotype** | **Clinical Significance** |
| :--- | :--- | :--- | :--- |
| **H272Y** | KPC-3 | Increased hydrolysis of ceftazidime; slightly reduced affinity for some carbapenems. | Associated with resistance to CAZ-AVI when combined with other mutations. |
| **D179Y** | KPC-31, KPC-33 | Reduced carbapenemase activity but increased resistance to CAZ-AVI. | Emerges during CAZ-AVI therapy; often leads to treatment failure. |
| **T243M, V240G** | KPC-8, KPC-9 | Altered substrate profile; increased ceftazidime hydrolysis. | Can confer resistance to ceftazidime-containing combinations. |
| **L167P, P169L** | KPC-4, KPC-5 | Enhanced activity against ceftazidime and cefepime. | May be selected by use of extended-spectrum cephalosporins. |
| **G243S** | KPC-12 | Increased affinity for avibactam, leading to higher susceptibility to CAZ-AVI. | Rare; may be associated with increased susceptibility to inhibitor combinations. |

The **D179Y** mutation is particularly clinically relevant. It is located in the Ω-loop and disrupts the hydrogen bonding network that stabilizes the deacylation machinery. This results in a significant reduction in the enzyme's ability to hydrolyze carbapenems, but it paradoxically confers resistance to CAZ-AVI. The mechanism is thought to involve a change in the conformation of the Ω-loop, which prevents avibactam from binding effectively while still allowing for the hydrolysis of ceftazidime [1, 16, 17].

### 4.2 Mutations in the Promoter Region

Mutations in the promoter region of blaKPC-2 can also have significant clinical consequences. Deletions in the region between the -35 and -10 boxes can alter the affinity of [RNA polymerase](/knowledge/bioinformatics/rna-polymerase-structure-transcription-mechanisms) for the promoter, leading to changes in gene expression. For example, the blaKPC-2a, blaKPC-2b, and blaKPC-2c variants have different promoter deletions that result in varying levels of KPC-2 production. These differences can affect the MICs of β-lactams and the susceptibility to β-lactamase inhibitors [15].

### 4.3 Clinical Differentials and Diagnostic Challenges

The detection of KPC-2-producing organisms can be challenging due to the variability in phenotypic resistance profiles. Some KPC-2 producers may appear susceptible to carbapenems by standard broth microdilution methods, particularly if the enzyme is expressed at low levels or if the strain has additional resistance mechanisms. This has led to the development of specialized phenotypic tests, such as the modified Hodge test (MHT), the Carba NP test, and the use of boronic acid-based inhibitors, which can specifically identify KPC-type enzymes [7, 8, 9]. However, molecular methods, including PCR and whole-genome sequencing, are now the gold standard for definitive identification of blaKPC-2 [10, 11, 12, 13, 14].

The clinical differential for a patient infected with a KPC-2-producing organism includes infections caused by other carbapenemase producers (e.g., NDM, OXA-48, VIM) and non-carbapenemase-producing carbapenem-resistant Enterobacterales (e.g., those with porin loss combined with ESBL/AmpC production). The distinction is critical for guiding therapy, as the treatment options differ significantly. For example, CAZ-AVI is active against KPC-2 producers but not against NDM-1 producers, while cefiderocol may be active against both but is subject to resistance mechanisms involving siderophore receptors [1, 15].

## 5. Host-Pathogen & Viral Interactions (If applicable)

### 5.1 Bacterial Interactions and Plasmid Biology

The primary "interaction" of blaKPC-2 is with its bacterial host and the mobile genetic elements that carry it. The gene is often part of a larger resistance plasmid that may also carry genes for resistance to other antibiotic classes, such as aminoglycosides (e.g., rmtB), fluoroquinolones (e.g., qnr), and colistin (e.g., mcr-1) [1, 5, 16, 17]. This co-localization allows for the co-selection of multiple resistance determinants under a single antibiotic pressure.

The fitness cost of carrying a large resistance plasmid can be significant. However, bacteria can ameliorate this cost through various mechanisms, including transcriptional regulation and compensatory mutations. A study by Buckner et al. demonstrated that the fitness cost of KPC-2-carrying plasmids is primarily ameliorated by transcriptional changes rather than genomic modifications, allowing the bacteria to maintain the plasmid without a significant growth disadvantage [2].

### 5.2 Interactions with Bacteriophages

Bacteriophages can interact with KPC-2-producing bacteria in several ways. They can act as vectors for the horizontal transfer of the blaKPC-2 gene through generalized or specialized transduction. This is a less common but potentially important mechanism of gene dissemination. Additionally, phage therapy is being explored as a treatment option for infections caused by multidrug-resistant organisms, including KPC-2 producers. The CRISPR-Cas system, which is a bacterial adaptive immune system against phages, has also been investigated as a tool to specifically target and inactivate blaKPC-2 and other resistance genes, thereby re-sensitizing the bacteria to antibiotics [3, 4].

### 5.3 Interactions with the Host Microbiota

The gut microbiota plays a crucial role in the colonization and infection dynamics of KPC-2-producing *K. pneumoniae*. Studies have shown that a high relative abundance of KPC-producing *K. pneumoniae* in the gut microbiota is a significant risk factor for subsequent bloodstream infection [5, 6]. The disruption of the normal microbiota, often due to antibiotic use, can create a niche for the colonization and overgrowth of resistant organisms, increasing the risk of invasive disease.

## 6. [Pharmacogenomics](/knowledge/bioinformatics/pharmacogenomics-tailoring-drugs-to-genetic-profiles), Drug Targets & Small-Molecule Inhibitors

### 6.1 Therapeutic Strategies Against KPC-2-Producing Organisms

The treatment of infections caused by KPC-2-producing organisms is challenging due to the broad resistance profile of these pathogens. The therapeutic arsenal includes:

- **Ceftazidime-Avibactam (CAZ-AVI):** This is a first-line agent for infections caused by KPC-2-producing Enterobacterales. Avibactam is a non-β-lactam β-lactamase inhibitor that covalently and reversibly inhibits KPC-2. However, resistance to CAZ-AVI can emerge during therapy, often due to mutations in the Ω-loop of KPC-2 (e.g., D179Y) [1, 16, 17].
- **Meropenem-Vaborbactam:** This is another β-lactam/β-lactamase inhibitor combination with activity against KPC-2 producers. Vaborbactam is a cyclic boronic acid inhibitor that forms a stable, reversible covalent bond with the active site serine of KPC-2.
- **Imipenem-Cilastatin-Relebactam:** Relebactam is a newer β-lactamase inhibitor that is structurally similar to avibactam. It is active against KPC-2 and is used in combination with imipenem and cilastatin.
- **Cefiderocol:** This is a siderophore-conjugated cephalosporin that exploits the bacterial iron transport system to gain entry into the periplasm. It is stable against hydrolysis by KPC-2 and many other β-lactamases. However, resistance can emerge through mutations in the ferric citrate transport system [15].
- **Polymyxins (Colistin, Polymyxin B):** These are cationic peptides that disrupt the outer membrane of Gram-negative bacteria. They are often used as a last-resort treatment for extensively drug-resistant infections, but resistance can emerge through various mechanisms, including modifications to the lipid A component of lipopolysaccharide [7, 8, 9, 10].
- **Tigecycline and Eravacycline:** These are glycylcycline antibiotics that are often active against KPC-2 producers, but their use is limited by pharmacokinetic considerations and the potential for resistance development.
- **Fosfomycin:** This is an old antibiotic that inhibits cell wall synthesis. It can be used in combination therapy for KPC-2-producing urinary tract infections, but resistance is a concern [16].
- **Aztreonam-Avibactam:** This combination is particularly useful against organisms that co-produce KPC-2 and metallo-β-lactamases (e.g., NDM-1), as aztreonam is stable against metallo-β-lactamases, and avibactam protects it from KPC-2.

### 6.2 Investigational Agents and Novel Approaches

- **New β-Lactamase Inhibitors:** Several novel β-lactamase inhibitors are in development, including taniborbactam and nacubactam, which have broader spectra of inhibition and may be active against KPC-2 variants that are resistant to avibactam.
- **CRISPR-Cas Antimicrobials:** The use of CRISPR-Cas systems to specifically target and cleave blaKPC-2 and other resistance genes is a promising approach to re-sensitize bacteria to antibiotics [3].
- **Anti-virulence Therapies:** For hypervirulent KPC-2-producing strains, targeting virulence factors (e.g., capsule synthesis, siderophore production) could be a therapeutic strategy to reduce pathogenicity without directly killing the bacteria.
- **Phage Therapy:** Bacteriophages that specifically lyse KPC-2-producing bacteria can be used as an alternative or adjunct to antibiotic therapy.

### 6.3 Pharmacogenomic Considerations

[Pharmacogenomics](/knowledge/bioinformatics/pharmacogenomics-tailoring-drugs-to-genetic-profiles), in the context of blaKPC-2, refers to the genetic variations in the gene that affect the susceptibility of the enzyme to inhibitors. The presence of specific mutations in blaKPC-2 can predict the efficacy of CAZ-AVI and other β-lactam/β-lactamase inhibitor combinations. For example, the detection of a D179Y mutation in a clinical isolate would strongly suggest that CAZ-AVI therapy would be ineffective, and alternative agents should be considered. Rapid molecular diagnostics that can detect these resistance mutations are therefore of great clinical value [11, 13].

## 7. Bioinformatic Resources & Database Accessions

The following table provides key database accessions and links for blaKPC-2 and its protein product.

| **Database** | **Identifier** | **Link** |
| :--- | :--- | :--- |
| **NCBI Gene** | 3828305 (blaKPC-2) | [NCBI Gene](https://www.ncbi.nlm.nih.gov/gene/3828305) |
| **UniProt** | Q9F663 | [UniProtKB - Q9F663](https://www.uniprot.org/uniprotkb/Q9F663/entry) |
| **RCSB PDB** | 2O5V | [RCSB PDB - 2O5V](https://www.rcsb.org/structure/2O5V) |
| **GenBank (Nucleotide)** | AY034847 (blaKPC-2 gene) | [GenBank - AY034847](https://www.ncbi.nlm.nih.gov/nuccore/AY034847) |
| **CARD (Comprehensive Antibiotic Resistance Database)** | ARO:3000260 (KPC-2) | [CARD - KPC-2](https://card.mcmaster.ca/ontology/3000260) |
| **Beta-Lactamase Database (BLDB)** | KPC-2 | [BLDB - KPC-2](http://www.bldb.eu/BLDB.php?class=A#KPC-2) |
| **Gene Ontology (GO)** | GO:0008800 (β-lactamase activity); GO:0046679 (response to antibiotic) | [QuickGO - GO:0008800](https://www.ebi.ac.uk/QuickGO/term/GO:0008800) |
| **STRING (Protein-Protein Interaction)** | Q9F663 | [STRING - Q9F663](https://string-db.org/network/Q9F663) |

## 8. Conclusion

blaKPC-2 is a paradigmatic example of a clinically significant antibiotic resistance gene. Its product, KPC-2, is a versatile serine β-lactamase capable of inactivating nearly all β-lactam antibiotics, including the last-resort carbapenems. The gene's location on mobile genetic elements has facilitated its global dissemination among diverse Gram-negative pathogens, leading to the emergence of carbapenem-resistant Enterobacterales (CRE) that are associated with high morbidity and mortality. The ongoing evolution of KPC-2 under selective pressure from novel β-lactamase inhibitors, particularly ceftazidime-avibactam, underscores the dynamic nature of antimicrobial resistance. Understanding the structural, functional, and epidemiological aspects of blaKPC-2 is essential for the development of effective diagnostic, therapeutic, and infection control strategies to combat this significant public health threat.

## Related Clinical & Scientific Guides

* [tpdA Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/microbiology-amr/tpda-gene-structure-function-pathway)
* [acm Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/microbiology-amr/acm-gene-structure-function-pathway)
* [P83002 Gene: Structure, Function, and Clinical Significance](/knowledge/bioinformatics/genes/microbiology-amr/p83002-gene-structure-function-pathway)

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