Quarantine and Inspection Agency

Anyang, South Korea

Quarantine and Inspection Agency

Anyang, South Korea
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Park J.Y.,Mississippi State University | Kim J.W.,Quarantine and Inspection Agency | Moon B.Y.,Mississippi State University | Moon B.Y.,Seoul National University | And 5 more authors.
Infection and Immunity | Year: 2015

Hexose phosphate is an important carbon source within the cytoplasm of host cells. Bacterial pathogens that invade, survive, and multiply within various host epithelial cells exploit hexose phosphates from the host cytoplasm through the hexose phosphate transport (HPT) system to gain energy and synthesize cellular components. In Escherichia coli, the HPT system consists of a two-component regulatory system (UhpAB) and a phosphate sensor protein (UhpC) that tightly regulate expression of a hexose phosphate transporter (UhpT). Although growing evidence suggests that Staphylococcus aureus also can invade, survive, and multiply within various host epithelial cells, the genetic elements involved in the HPT system in S. aureus have not been characterized yet. In this study, we identified and characterized the HPT system in S. aureus that includes the hptRS (a novel two-component regulatory system), the hptA (a putative phosphate sensor), and the uhpT (a hexose phosphate transporter) genes. The hptA, hptRS, and uhpT markerless deletion mutants were generated by an allelic replacement method using a modified pMAD-CM-GFPuv vector system. We demonstrated that both hptA and hptRS are required to positively regulate transcription of uhpT in response to extracellular phosphates, such as glycerol-3-phosphate (G3P), glucose-6-phosphate (G6P), and fosfomycin. Mutational studies revealed that disruption of the hptA, hptRS, or uhpT gene impaired the growth of bacteria when the available carbon source was limited to G6P, impaired survival/multiplication within various types of host cells, and increased resistance to fosfomycin. The results of this study suggest that the HPT system plays an important role in adaptation of S. aureus within the host cells and could be an important target for developing novel antistaphylococcal therapies. © 2015, American Society for Microbiology.


PubMed | Quarantine and Inspection Agency, University of California at Los Angeles, Mississippi State University and Seoul National University
Type: Journal Article | Journal: Infection and immunity | Year: 2015

Hexose phosphate is an important carbon source within the cytoplasm of host cells. Bacterial pathogens that invade, survive, and multiply within various host epithelial cells exploit hexose phosphates from the host cytoplasm through the hexose phosphate transport (HPT) system to gain energy and synthesize cellular components. In Escherichia coli, the HPT system consists of a two-component regulatory system (UhpAB) and a phosphate sensor protein (UhpC) that tightly regulate expression of a hexose phosphate transporter (UhpT). Although growing evidence suggests that Staphylococcus aureus also can invade, survive, and multiply within various host epithelial cells, the genetic elements involved in the HPT system in S. aureus have not been characterized yet. In this study, we identified and characterized the HPT system in S. aureus that includes the hptRS (a novel two-component regulatory system), the hptA (a putative phosphate sensor), and the uhpT (a hexose phosphate transporter) genes. The hptA, hptRS, and uhpT markerless deletion mutants were generated by an allelic replacement method using a modified pMAD-CM-GFPuv vector system. We demonstrated that both hptA and hptRS are required to positively regulate transcription of uhpT in response to extracellular phosphates, such as glycerol-3-phosphate (G3P), glucose-6-phosphate (G6P), and fosfomycin. Mutational studies revealed that disruption of the hptA, hptRS, or uhpT gene impaired the growth of bacteria when the available carbon source was limited to G6P, impaired survival/multiplication within various types of host cells, and increased resistance to fosfomycin. The results of this study suggest that the HPT system plays an important role in adaptation of S. aureus within the host cells and could be an important target for developing novel antistaphylococcal therapies.


Park H.-J.,Quarantine and Inspection Agency | Go E.K.,Quarantine and Inspection Agency | Wee S.-H.,Quarantine and Inspection Agency | Yoon H.,Quarantine and Inspection Agency | And 4 more authors.
Korean Journal for Food Science of Animal Resources | Year: 2012

This study was carried out to examine foodborne pathogenic contamination from 1,080 samples of cooked hams and sausages at 10 Korean processing facilities in 2010. The samples were collected from the six primary and additional sterilization products in same lot. To detect Salmonella spp., Staphylococcus aureus, Listeria monocytogenes and Clostridium perfringens in those products (n=1,080), the domestic standard method for Processing and Ingredients Specification of Livestock Products was used. As a result, Salmonella spp. was not detected in all 636 ham and 444 sausage samples. However, L. monocytogenes was detected in four (0.6%) ham and eight (1.8%) sausage samples from five manufactures. S. aureus was also only detected in 4 (0.6%) ham samples from two manufacturers, and C. perfringens was detected in 3 (0.5%) ham samples from three manufacturers, the contamination levels of these pathogens were less than 100 CFU/g. In conclusion, the results of this study indicate that the additional sterilization step of processing manufacturers could not assist to control the foodborne pathogenic bacteria.


PubMed | Quarantine and Inspection Agency
Type: Journal Article | Journal: Parasitology international | Year: 2013

This study was carried out to identify the tick species that infest grazing cattle and to determine the presence of tick-borne pathogens transmitted by these ticks in Korea. A total of 903 ticks (categorized into 566 tick pools) were collected from five provinces during 2010-2011. The most prevalent tick species was Haemaphysalis longicornis, followed by three Ixodes spp. ticks. The collected ticks were infected with both rickettsial and protozoan pathogens. In all, 469 (82.9%) tick pools tested positive for the Anaplasma/Ehrlichia 16S rRNA gene, whereas 67 (11.8%) were positive for the Babesia/Theileria 18S rRNA gene. Among the rickettsial pathogens, E. canis was detected with the highest rate (22.3%), followed by A. platys (20%), E. chaffeensis (19.4%), E. ewingii (19.3%), Rickettsia sp. (12.4%), A. phagocytophilum (5.5%) and E. muris (0.5%). Among the protozoan pathogens, T. equi was detected with the highest rate (7.2%), followed by T. sergenti/T. buffeli (3.7%) and B. caballi (0.35%). Simultaneous infections with up to seven pathogens were also identified. In particular, ticks infected with rickettsial pathogens were also infected with protozoan pathogens (22 samples). All five provinces investigated infected with tick-borne pathogens.

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