MMBIO 221 Final Exam Questions and Answers with Complete Solutions Graded A 2024

An acid-fast pathogen; over one-third of the world's population is infected; caseous necrosis is a hallmark of disease; MDR, XDR, BCG, and DOTS apply to this organism. Mycobacterium tuberculosis The most common cause of non-nosocomial urinary tract infections, usually in women; also the cause of the life-threatening disease known as hemolytic uremic syndrome. Escherichia coli Brainpower Read More Causes a life-threatening disease in individuals experiencing crowded and stressful living conditions. Much more common in military barracks, prisons, and college dormitories. Gram-negative cocci that infect the central nervous system. Neisseria meningitidis An acid-fast pathogen; the cause of Hansen's disease; cannot be grown in cell-free culture; associated with armadillos; causes deformities and nerve damage; grows best at 30 °C. Mycobacterium leprae Most infections in humans result from consumption of food contaminated with animal feces; particularly common in poultry, eggs, and reptiles; causes diarrhea. Salmonella enterica An enteric pathogen that causes a severe form of dysentery; transmitted by contaminated food or water; low infectious dose; can spread from cell to cell by polymerizing host cell actin. Shigella sonnei When cultured on agar, this organism differentiates into peritrichous flagella that allow them to swarm over the surface in concentric rings; frequently causes UTIs and produces large amounts of urease which leads to infection-induced kidney stones. Proteus mirabilis An enteric pathogen with a large anti-phagocytic capsule; can cause urinary tract infections, wound infections, bacteremia, pneumonia, and meningitis; a major CRE. Klebsiella pneumoniaev Gram-negative cocci that causes a sexually transmitted infection; can also cause pelvic inflammatory disease and ophthalmia neonatorum; grown on modified Thayer-Martin medium. Neisseria gonorrhoeae Small gram-positive anaerobic rod commonly found on the skin; causes about 85% of acne cases in adolescents and young adults. Propionibacterium (Cutibacterium) Causes the plague or ‘black death’. Has probably killed more humans than any other single infectious agent; transmitted by flea bites or infectious aerosols. Yersinia pestis Causes tularemia, rabbit fever, or tick fever; one of the smallest, but most infectious organisms known; wide host range, but not found below the equator. Francisella Possesses many virulence factors. Responsible for about 10% of nosocomial infections, especially in burn wards; infects the lungs of cystic fibrosis patients and produces pyocyanin, a blue-green pigment, and a very distinctive odor. Pseudomonas aeruginosa Slightly helical, highly motile bacterium that causes gastritis and most peptic ulcers; produces potent urease to neutralize stomach acid. Helicobacter pylori Is the leading cause of nontraumatic blindness in humans; energy parasite with a two-stage life cycle; one of the most common sexually transmitted organisms in U.S.: lymphogranuloma venereum (LGV) strain. Chlamydia trachomatis Curved gram-negative rod that causes explosive diarrhea; toxin activates adenylate cyclase causing fluid and electrolyte loss; pandemic strains are O1 El Tor and O139 Bengal. Vibrio cholerae Obligate intracellular bacterium that causes Rocky Mountain Spotted Fever; transmitted by bite of Dermacentor hard ticks. Rickettsia rickettsii