Photonic detection of bacterial pathogens in living hosts

Abstract

The study of pathogenic processes is often limited to ex vivo assays and cell-culture correlates. A greater understanding of infectious diseases would be facilitated by in vivo analyses. Therefore, we have developed a method for detecting bacterial pathogens in a living host and used this method to evaluate disease processes for strains of Salmonella typhimurlum that differ in their virulence for mice. Three strains of Salmonella were marked with bioluminescence through transformation with a plasmid conferring constitutive expression of bacterial luciferase. Detection of photons transmitted through tissues of animals infected with bioluminescent Salmonella allowed localization of the bacteria to specific tissues. In this manner progressive infections were distinguished from those that were persistent or abortive. We observed patterns of bioluminescence that suggested the caecum may play a pivotal role in Salmonella pathogenesis. In vivo efficacy of an antibiotic was monitored using this optical method. This study demonstrates that real time non-invasive analyses of pathogenic events and pharmacological monitoring can be performed in vivo.

MicroPET imaging of Cre–loxP-mediated conditional activation of a herpes simplex virus type 1 thymidine kinase reporter gene

“…This PRG gene activated by loxP-dependent recombination allowed us to image noninvasively the PRG expression by microPET and to identify the tissues that express the Cre recombinase. Although development of a cooled charged coupled device (CCD) camera also allows the noninvasively imaging of the expression of firefly luciferase gene in small animals, 20,21 it is limited by the lack of tomographic information and full quantitation capability.…”

Quantitative mouse model of implant‐associated osteomyelitis and the kinetics of microbial growth, osteolysis, and humoral immunity

“…25 Contag and colleagues were the first to utilize bioluminescent strains of pathogens to study infection longitudinally in mice. 26 Subsequent studies have proven the value of BLI over conventional methods in studying disease and therapeutic interventions in animals. 25 More recently, this group generated bioluminescent S. aureus Xen29 for this purpose.…”

Non-viral gene transfer of murine spleen cells achieved by in vivo electroporation

“…It has recently been shown that if the light emitted in vivo from the luciferaseexpressing cells is sufficient, it can be detected in anesthetized animals through the tissues with a sensitive CCD camera. [24][25][26] We thus used this new method to visualize the luciferase activity in vivo and we also used the standard procedure to measure it on tissue samples. Indeed, we could easily detect the luciferase activity after an IME (Figure 2a).…”