title: Quantification of cell infection caused by Listeria monocytogenes invasion.
abstract: Listeria monocytogenes causes a life-threatening food-borne disease known as Listeriosis. Elderly,immunocompromised, and pregnant women are primarily the victims of this facultative intracellular Gram-positive pathogen. Since the bacteria survive intracellularly within the human host cells they are protected against the immune system and poorly accessed by many antibiotics. In order to screen pharmaceutical substances for their ability to interfere with the infection, persistence and release of L. monocytogenes a high content as say is required. We established a high content screen (HCS) using the RAW 264.7 mouse macrophage cell line seeded into 96-well glass bottom microplates. Cells were infected with GFP-expressing L. monocytogenes and stained thereafter with Hoechst 33342.Automated image acquisition was carried out by the Scan(R) screening station. We have developed an algorithm that automatically grades cells in microscopy images of fluorescent-tagged Listeria for the severity of infection. The grading accuracy of this newly developed algorithm is 97.1% as compared to a 74.3%grading accuracy we obtained using the commercial Olympus Scan(R) software.
authors.affiliation: Department of Electrical Engineering, Pakistan Institute of Engineering & Applied Sciences (PIEAS), P.O. Nilore, Islamabad 45650, Pakistan. gilgiti@yahoo.com
authors.forename: Muhammad
authors.initials: M
authors.lastname: Arif
authors.forename: Nasir M
authors.initials: NM
authors.lastname: Rajpoot
authors.forename: Tim W
authors.initials: TW
authors.lastname: Nattkemper
authors.forename: Ulrike
authors.initials: U
authors.lastname: Technow
authors.forename: Trinad
authors.initials: T
authors.lastname: Chakraborty
authors.forename: Nicole
authors.initials: N
authors.lastname: Fisch
authors.forename: Nickels A
authors.initials: NA
authors.lastname: Jensen
authors.forename: Karsten
authors.initials: K
authors.lastname: Niehaus
mesh_terms: D000465:Algorithms; D000818:Animals; D058491:Bacterial Load / Q000379:methods*; D002460:Cell Line; D002467:Cell Nucleus; D003584:Cytological Techniques / Q000379:methods*; D049452:Green Fluorescent Proteins / Q000737:chemistry / Q000378:metabolism; D007091:Image Processing, Computer-Assisted / Q000379:methods; D008089:Listeria monocytogenes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D008088:Listeriosis / Q000145:classification* / Q000382:microbiology*; D008264:Macrophages / Q000382:microbiology*; D051379:Mice; D008856:Microscopy, Fluorescence / Q000379:methods; D012984:Software
chemical_list: D049452:Green Fluorescent Proteins