Bacteriology classification of bacteria & select gram ⊕ & gram ⊝ infections

Gram-positive Organisms (6) Listeriosis Listeria monocytogenes  Gram ⊕, facultative intracellular rod (bacillus) acquired by ingestion of unpasteurized dairy products & cold deli meats, via transplacental transmission, or by vaginal transmission during birth  Forms “rocket tails” (red) via actin polymerization that allow intracellular movement and cell-to- cell spread across cell membranes, thereby avoiding antibody  Can cause amnionitis, septicemia, and spontaneous abortion in pregnant women, granulomatosis infantiseptica, neonatal meningitis, meningitis in elderly and immunocompromised patients; mild, self-limited gastroenteritis in healthy individuals  Treatment: ampicillin in infants, immunocompromised and elderly as empirical treatment Marc Imhotep Cray, M.D.of meningitis