S. aureus USA300 LAC (AH1263)金黄色葡萄球菌NTCC® strain菌株 BioVector NTCC质粒载体菌种细胞基因保藏中心

BioVector® NTCC® S. aureus USA300 LAC (AH1263)金黄色葡萄球菌NTCC® strain菌株

In vivo bioluminescence imaging has been used to monitor Staphylococcus aureus infections in preclinical models by employing bacterial reporter strains possessing a modified lux operon from Photorhabdus luminescens. However, the relatively short emission wavelength of lux (peak 490 nm) has limited tissue penetration. To overcome this limitation, the gene for the click beetle (Pyrophorus plagiophtalamus) red luciferase (luc) (with a longer >600 emission wavelength), was introduced singly and in combination with the lux operon into a methicillin-resistant S. aureus strain. After administration of the substrate D-luciferin, the luc bioluminescent signal was substantially greater than the lux signal in vitro. The luc signal had enhanced tissue penetration and improved anatomical co-registration with infected internal organs compared with the lux signal in a mouse model of S. aureus bacteremia with a sensitivity of approximately 3 × 104 CFU from the kidneys. Finally, in an in vivo mixed bacterial wound infection mouse model, S. aureus luc signals could be spectrally unmixed from Pseudomonas aeruginosa lux signals to noninvasively monitor the bacterial burden of both strains. Therefore, the S. aureus luc reporter may provide a technological advance for monitoring invasive organ dissemination during S. aureus bacteremia and for studying bacterial dynamics during mixed infections.
We compared the new AH4807 (lux) against the existing bioluminescent S. aureus strains USA300 LAC::lux15, LAC4303 (lux)14,56 and Xen36 (lux)11 (Table 1) in terms of growth, luminescence output, and stability in vitro. For these comparison strains, USA300 LAC::lux was constructed by moving the original lux kanamycin resistant (KanR) cassette from strain Xen2957. LAC4303 (lux) has the lux construct on an integrated plasmid on the bacterial chromosome of USA300 LAC, and Xen36 (lux) has the lux construct inserted on a stable plasmid in the methicillin-sensitive S. aureus strain Wright. All four strains grow fairly similarly, with USA300 LAC::lux lagging slightly behind (see Supplemental Data, Fig. S1A). LAC4303 (lux) generated the most bioluminescence during a 10-hour time course, followed by both AH4807 (lux) and Xen36 (lux) which behaved similarly over time (Fig. S1A), and finally USA300 LAC::lux had the lowest luminescence output. LAC4303 (lux) is constructed with a temperature-sensitive plasmid called pRP119514 and we predicted this plasmid might undergo excision from the chromosome at lower temperatures. Indeed, we observed significant excision rates at 30 °C as determined by PCR (Fig. S1B,C), which were reduced at 37 °C and non-existent at 43 °C. Despite the instability, we did not observe a deleterious impact on overall LAC4303 (lux) luminescence at lower temperatures. The AH4807 (lux) plasmid pHC125 was stable at all temperatures as anticipated

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