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Mycoplasma The smallest free-living organisms in nature! Mycoplasma pneumoniae • Figure 26-1 “fried egg appearance” of colonies • Page 376 • the most significant human pathogen among the Mycoplasmas • Readings question #1: Where do the Mycoplasma pneumoniae colonies adhere? How do they spread? What diseases are caused by this bacterium? Rickettsia • Page 377 • only reproduce within a mammalian cell • induce phagocytosis; enter cytoplasm; reproduce by binary fission Readings question #2: What is the most severe rickettsial infection, and what organism causes it? Rocky Mountain Spotted Fever Rickettsia prowazekii • Readings question #3: • How is the Rickettsia prowazekii microbe transmitted to produce epidemic typhus? • Signs and symptoms: high and prolonged fever that lasts at least 2 weeks; stupor; rash that darkens as disease progresses • Anne Frank Treatment • tetracycline, doxycycline, chloramphenicol • eliminate conditions • vaccines for military Rickettsia typhi • Page 378 • sporadic • murine: Latin for “mouse” Readings question #4: How is the Rickettsia typhi microbe transmitted to produce endemic typhus? • treatment: tetracycline, doxycycline, chloramphenicol • rat control is best preventive measure Coxiella burnetti • • • • • • parasite of several arthropods birthing: organisms shed in high numbers resistant to heat, drying, & many disinfectants inhaling a single pathogen can cause infection pasteurization temperature raised in 1956 responsible for Q fever Q (Query) Fever • Wide range of clinical symptoms • 60% asymptomatic • Acute: high fevers (104-105 degrees), severe headache, general malaise, confusion, sore throat, chills, sweats, non-productive cough, nausea, vomiting, diarrhea, abdominal pain and chest pain • pneumonia: 30-50% patients; hepatitis Chronic Q Fever • • • • • Infection persists for more than 6 months 1 year or 20 years Endocarditis Transplant recipients, cancer, kidney disease Treatment: acute- doxycycline chronic- doxycycline & quinolones doxycycline & hydroxychloroquine Prevention education appropriate disposal restrict access pasteurized milk laboratory clothing vaccination quarantine holding facilities routine testing Chlamydia • Page 379 Readings question #5: What are the 3 species of Chlamydias that are significant pathogens for humans? What is the “elementary body” and “reticulate body”? Chlamydias are transmitted to humans by interpersonal contact or by airborne respiratory routes. Chlamydial pneumonia • • • • outbreaks among college students transmitted by the respiratory route 50% U.S. population has antibodies treatment: tetracycline Chlamydia trachomatic • Page 380 • Causative agent for: trachoma Lymphogranuloma veneruem NGU (non-gonococcal urethritis) or NSU (non-specific urethritis) Trachoma • Greek: “rough eye” • arid parts of Africa and Asia, almost all children are infected early in their lives • 500 million active cases worldwide and 7 million blinded victims • occurs occasionally in the southwestern U.S. • transmitted by hand contact or by sharing personal objects Trachoma (cont’d) • • • • • • • conjunctivitis leads to permanent scarring long-term mechanical abrasion of the cornea turned-in eyelashes secondary infections tetracycline ointment partial immunity sanitary practices and health education Lymphogranuloma venereum (LGV) • Genital infections associated with an increased risk of cervical cancer • NGU/NSU: any inflammation of the urethra that is not caused by Neisseria gonorrhoeae – painful urination and watery discharge – coinfection with C. trachomatis Chlamycia psittaci • Infected birds will usually have diarrhea, ruffled feathers, respiratory illness, and a generally “droopy appearance” Prions “small proteinaceous infectious agents without a nucleic acid genome……produce spongiform encephalopathies” Pathogenicity • Page 384 • abnormally folded proteins that cause the proteins to clump • diseases have a long incubation time • CNS damage is insidious • no fever and inflammation Readings Question #6 • Why are prions of a particular concern to embalmers? Creutzfeldt-Jakob Disease • • • • • progressive disease spongiform degeneration of the brain rare: 200 cases/year in the U.S. no treatment for CJD, always fatal embalming implications discussed in FUN 247 and FUN 249