|
Bacterial Pathogens III Gram negative, Acid-fast, Mycoplasma and Prions February 2000 ZOONOTIC BACTERIAL DISEASES (these are diseases that natural exist in animal populations and humans are an accidental host) 1) Lyme Disease a) Caused by Borrelia burgdorferi: gram negative spiral bacterium b) Spread by tick bite, by a particular type of tick c) Bull’s Eye rash d) Chronic infection, heart disease, arthritis 1996, cases inc’d 41% from 11,700 to 16,461 in NY, Conn, NJ, Penn, RI e) Vaccine available: controversial, 70% effective, does not protect against other tick borne diseases. 2) Rocky Mountain Spotted fever a) Caused by Rickettsia rickettsii, pleomorphic rods, obligate intracellular organisms b) Disease spread by tick bite c) Bacterium can be spread to offspring by transovarian passage d) Disease: Rash 1 wk after bite, palms and soles unlike viral rashes fever, headache, mortality rate of 3%, 1000 cases each yr. e) Treat with tetracycline or choramphenicol 4) Brucellosis: Brucella abortis (B. suis, and B. melitensis) DO NOT NEED TO KNOW THIS ORGANISM (2/2000) a) Very small, gram-negative aerobic rods b) Require CO2, enriched media, difficult to grow c) B. abortus most common in U.S. In cattle, (beef, buffalo) transmission via milk d) Infection is via break in skin or mucus membranes, bacteria are intracellular e) Diagnosis: Very difficult, serology is best way f) Treatment: Long for several weeks with tet and strep. GRAM NEGATIVE RODS 1) Pseudomonas aeruginosa a) Gram negative, motile rod, aerobe, can use nitrate and oxygen as terminal electron acceptor b) Ubiquitous in the environment c) Diseases Opportunitistic pathogen primarily Skin infections due to hot tubs Nosocomial infections Burn patients, toxin (exotoxin A, ADP-ribosylating enzyme), pili and perhaps motility involved in pathogenesisa) Cystic Fibrosis patients get lung infections that are usually chronic 2) Yersinia : Yersinia pestis a) Gram negative rod shaped bacterium b) Causes disease of plague A ZOONOTIC DISEASE 1) Bubonic: systemic infection due to bite of flea lymphatics are infected and in groin area get very large, buboes This form of disease spread by bite 2) Pneumonic: can arise from bubonic Can be spread by aerosol, infectious Pneumonia-like disease Y.
Approximate Word count = 950
Approximate Pages = 3.8
(250 words per page double spaced)
|
|
