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Updated: Oct 8, 2026
Following in Real Time the Impact of Pneumococcal Virulence Factors in an Acute Mouse Pneumonia Model Using Bioluminescent Bacteria
Published on: February 23, 2014
Visualizing pneumococcal infections in the lungs of live mice using bioluminescent Streptococcus pneumoniae
K P Francis1, J Yu, C Bellinger-Kawahara
1Xenogen Corporation, Alameda, California 94501, USA. kfrancis@xenogen.com
Abstract:
Animal studies with Streptococcus pneumoniae have provided valuable models for drug development. In order to monitor long-term pneumococcal infections noninvasively in living mice, a novel gram-positive lux transposon cassette, Tn4001 luxABCDE Km(r), that allows random integration of lux genes onto the bacterial chromosome was constructed. The cassette was designed so that the luxABCDE and kanamycin resistance genes were linked to form a single promoterless operon. Bioluminescence and kanamycin resistance only occur in a bacterial cell if this operon has transposed downstream of a promoter on the bacterium's chromosome. S. pneumoniae D39 was transformed with plasmid pAUL-A Tn4001 luxABCDE Km(r), and a number of highly bioluminescent colonies were recovered. Genomic DNA from the brightest D39 strain was used to transform a number of clinical S. pneumoniae isolates, and several of these strains were tested in animal models, including a pneumococcal lung infection model. Strong bioluminescent signals were seen in the lungs of the animals containing these pneumococci, allowing the course and antibiotic treatment of the infections to be readily monitored in real time in the living animals. Recovery of the bacteria from the animals showed that the bioluminescent signal corresponded to the number of CFU and that the lux construct was highly stable even after several days in vivo. We believe that this lux transposon will greatly expand the ability to evaluate drug efficacy against gram-positive bacteria in living animals using bioluminescence.
Insights
A novel bioluminescent transposon allows noninvasive monitoring of Streptococcus pneumoniae infections in mice. This tool enables real-time tracking of infection progression and antibiotic treatment efficacy in vivo.
Area of Science:
- Microbiology
- Bacterial Genetics
- Infectious Diseases
Background:
- Streptococcus pneumoniae infections pose significant public health challenges.
- Animal models are crucial for developing new antimicrobial therapies.
- Noninvasive monitoring methods are needed to track infection dynamics and treatment responses in vivo.
Purpose of the Study:
- To develop a novel bioluminescent reporter system for noninvasive, long-term monitoring of Streptococcus pneumoniae infections in living animals.
- To enable real-time evaluation of antibiotic treatment efficacy against gram-positive bacterial infections.
Main Methods:
- Construction of a novel gram-positive lux transposon cassette (Tn4001 luxABCDE Km(r)) for random integration of lux genes.
- Transformation of Streptococcus pneumoniae strains with the lux transposon.
- Testing of bioluminescent S. pneumoniae strains in a murine pneumococcal lung infection model.
Main Results:
- Successful generation of highly bioluminescent S. pneumoniae strains.
- Detection of strong bioluminescent signals in the lungs of infected mice, allowing real-time monitoring.
- Correlation between bioluminescence and bacterial load (CFU) in vivo.
- Demonstrated stability of the lux construct during infection.
Conclusions:
- The developed lux transposon system provides a powerful tool for noninvasive, real-time monitoring of S. pneumoniae infections in vivo.
- This technology facilitates the evaluation of drug efficacy against gram-positive bacteria in living animal models.
- The system enhances the ability to study infection dynamics and assess therapeutic interventions.
