Phylogenetic Insights into Emergence and Spread of Antibiotic Resistance in CRKP
Overview
This study used whole-genome sequencing and phylogenetic analysis to differentiate between de novo evolution and cross-transmission as pathways for antibiotic resistance in carbapenem-resistant Klebsiella pneumoniae (CRKP) ST258 isolates. Distinct clinical risk factors and antibiotic exposures were associated with each resistance acquisition pathway, highlighting the complex interplay between bacterial genetics, patient factors, and clinical practices.
Background
Antibiotic resistance, particularly in multidrug-resistant pathogens like CRKP, poses a critical public health threat by limiting treatment options and reducing cure rates. Resistance can arise either through de novo evolution within a host or via cross-transmission of resistant strains between patients, each requiring different prevention strategies. Understanding these distinct pathways is essential to tailor interventions such as antimicrobial stewardship and infection control measures. This study applies a phylogenetic framework to clinical isolates from long-term acute care hospitals to elucidate the drivers of resistance emergence and dissemination.
Data Highlights
Antibiotic
Resistance Pathway
Associated Risk Factors
Trimethoprim-sulfamethoxazole (TMP-SMX)
Emergence and Spread
Exposure to TMP-SMX
Colistin
Emergence and Spread
Exposure to Colistin
Novel β-lactam/β-lactamase inhibitors (BL/BLI)
Emergence
Exposure to BL/BLI
Amikacin
Spread
Exposure to Amikacin
Other Clinical Factors
Spread
Stage IV + decubitus ulcers, gastrostomy tubes
Key Findings
Phylogenetic analysis of 386 CRKP ST258 isolates revealed clade-specific differences in rates of resistance emergence and spread for five antibiotics.
De novo resistance emergence and cross-transmission contribute differently to the burden of resistance depending on the antibiotic.
Exposure to the specific antibiotic was an independent risk factor for resistance emergence (TMP-SMX, colistin, BL/BLI) and for resistance spread (TMP-SMX, amikacin, colistin).
Comorbidities such as stage IV decubitus ulcers and presence of gastrostomy tubes were uniquely associated with resistance spread.
The study introduced a phylogenetic framework and an R package (phyloAMR) to distinguish resistance acquisition pathways using genomic and clinical data.
Clinical Implications
Clinicians should consider both antibiotic exposure and patient-specific factors such as comorbidities and indwelling devices when assessing risk for resistance emergence and spread. Tailored interventions including antimicrobial stewardship to limit de novo resistance and stringent infection control to prevent cross-transmission are critical. The phylogenetic approach provides a valuable tool to inform targeted strategies in healthcare settings.
Conclusion
This phylogenetic framework enhances understanding of the distinct mechanisms driving antibiotic resistance in CRKP, enabling more precise identification of risk factors and informing tailored prevention efforts. Integrating genomic data with clinical metadata offers a powerful approach to combat the antibiotic resistance crisis.
References
Gontjes et al. 2024 -- Understanding the Phylogenetic Framework of Antibiotic Resistance to Illuminate the Mechanisms of Emergence and Dissemination
