Survey of Microbes Part I: Important prokaryotes Gram negative organisms, archaea, and others

1. Survey of MicrobesPart I: Important prokaryotesGram negative organisms, archaea, and others

2. IMPORTANT GRAM NEGATIVE PROTEOBACTERIA

3. G- cocci • Neisseria: ________________ • N. gonorrhoeae – _____________ = ________________ • Has fimbriae/pili to attach to genital epithelium and invade • Causes infiltration of pus/inflammation • Fastidious – diagnose on chocolate agar • N. meningitidis • Meningococcal meningitis – vaccine available and highly recommended for college students (spread by close/direct contact) • Penicillin sensitive?

4. Disease/Treatments • Adults: genital, urinary, anal infections posisble • neonatal eye infection (can prevent with erythromycin eye drops) • Men can be asymptomatic • some show “gleet” (copious purulent discharge) – see link to images on supplement site. • Women: pelvic inflammatory disease • Treatment: many antibiotics (e.g. doxycycline, cipro, z-pack) • Many are now resistant! (e.g. –cillins; tetracycline)

5. most cases are associated with _____________and genital ______________ infections Long term infection  organisms migrate into uterus, fallopian tubes Major cause of infertility and chronic pelvic pain PID • Sexually active teenagers are more likely to develop PID than are older women. • The more sexual partners a woman has, the greater her risk of developing PID. See web link: http://www.niaid.nih.gov/factsheets/stdpid.htm

9. Figure 23. Gonorrhea — Positivity among 15- to 24-year-old women tested in family planning clinics by state: United States and outlying areas, 2007

10. Gram negative rods

12. Gram - rods Enterobacteriaceae – shared characteristics • ____________________; Small rods (4-5 microns long) • Peritrichous flagella (exception: Klebsiella and Shigella are non motile) • All ferment glucose (produce acid) – used for ID on differential agar • Have various surface antigens to: avoid phagocytosis, aid in adherence, SEPTIC SHOCK (associated with LPS)

13. _______________ (LPS) – just one antigen on the outer membrane of Gram-negative bacteria.

14. Gram - rods LPS - lipopolysaccharide • Toxicity is associated with the lipid component (Lipid A) and immunogenicity is associated with the polysaccharide components. • O antigens also are components of LPS. • LPS elicits a variety of inflammatory responses in an animal, including fever. • MOST LPS IS RELEASED________________________________________________

15. Gram - rods Pathogenesis • Because of their cell envelope structure: • tolerant to bile salts and toxins in GI tract • Resistant to many antimicrobials produced by the host • Possibly resistant to phagocytosis • Also – LPS may be involved (along with pili, fimbrae) in binding host tissue

16. Gram - rods G- bacilli – Enterobacteriaceae • _________(strain O157:H7) – enterohaemorrhagic; common food poisoning; beef – outbreaks in hamburger meat • ___________________ (typhoid fever) – • ______________________ - common food poisoning (salmonellosis) ; poultry • Shigella flexneri, S. dysenteriae – bloody diarrhea; dysentery; invades mucosa shed lining of intestines • up to 50% of all diarrhea deaths can be attributed to bacillary dysentery!! • 1 M cases/yr (4% death rate) READ NEWS ARTICLE on Salmonella in peanut butter

17. Gram - rods Some toxins produced by enteric bacteria • ______________(from ET E. coli, Vibrio) – lead to secretion of lots of water by intestinal cells • ________________ (Shigella and E. coli O157H7) – destroys host ribosomes  causes cell death! What is the result? • ______________ (come E. coli strains) – destroy RBCs • Invasins (Salmonella, Shigella) – invade cells (can grow intracellularly)

18. A quick note on diarrhea… • Traveller’s diarrhea: due to contaminated water and foods; in developing countries, risk is 30-50% for travelers (1-2 wk stay) • Food poisoning: can be due to food itself (bacteria or virus living in that animal or its waste), poor food preparation (mixing cooked with uncooked) or due to unsanitary practices of food handler (fecal-oral transmission).

19. G- bacilli Other important Enterobacteriaceae • Yersinia pestis (bubonic plague) – • Buboes – large, swolen lymph nodes • killed more people than any other ID (killed ¼ Europe! – 25 M – in the 14th C) • transmitted by ___________during blood meal • MANY virulence factors • Klebsiella pneumoniae – pneumonia; has ___________, evades phagocytosis

21. G- bacilli (some others) • ___________________________(whooping cough) – DPT vaccine – toxin kills ciliated cells • Pseudomonas aeruginosa (opportunistic infections – grows everywhere) – slime layers, fimbrae • Haemophilus influenzae – MANY diseases!Meningitis, ear infection, sinusitis, pneumonia, septicemia, arthritis, epiglottitis (life threatening) – some strains have capsule; vaccine available • Bacteroides – major constituent of gut flora; usually commensalistic but can grow elsewhere and cause problems (resistant to Abt)

22. G- curved________________, the cause of Asiatic cholera. • Watery, profuse diarrhea  dehydration  shock  renal failure  death • Spread by contamination (fecal/oral esp. travel to endemic countries) and by seafood (other Vibrio spp.) • uses glycocalyx to anchor to epithelium • Produces cholera-toxin (enterotoxin) READ NEWS ARTICLE on cholera outbreak in Zimbabwe

23. G- Spiral shaped • Have a rigid cell wall and polar flagella • Campylobacter jejuni -- bacterial diarrhea, especially in children. • undercooked poultry or shellfish, or untreated drinking water. • _________________________– peptic ulcers; colonizes gastric mucosal cells of humans • Mode of transmission uncertain • Dx – gastric biopsy and urease test • >80% ulcers are Hp!

25. Rickettsias • Very tiny! • Most are pathogens (vector borne = spread by arthropods) • ________________________________ parasites • Rickettsia rickettsii – Rocky Mtn. Spotted Fever – ticks • Rickettsia typhi – endemic typhus (lice) • Coxiella burnetti – Q fever (http://www.cdc.gov/ncidod/dvrd/qfever/)

26. Spots due to small hemorrhages

27. Other phyla of prokaryotes Chlammydias, Spirochetes, Photosynthetic bacteria, Archaea (extremophiles)

28. Spirochetes Cross section Borrelia burgdorferi Treponema pallidum • phylogenetically distinct group very thin, flexible, spiral-shaped • move by means of axial filaments (periplasmic flagella). • Most spirochetes are free living or harmless; a few are pathogens of animals • _____________________– Lyme disease – humans + dogs • _____________________– syphillis – hook to embed in host cell

29. Spirochetes – Treponema pallidum Syphillis • Sores occur mainly on the external genitals, vagina, anus, or in the rectum. (also on lips and in mouth) • Transmitted by direct contact (Also congenitally) • first stage - small sore disappears in 2 to 8 weeks. • second and third stages -- progressively worse eventually lead to brain, heart, and blood vessel damage if not diagnosed and treated. • syphilis is 100% curable with penicillin, yet there is now more syphilis than since the late 1940s, and it is spreading rapidly. • Rising rapidly in white, homosexual male demographic

34. Chlammydias • Obligate intracellular parasites (cannot survive without host cell) • VERY, very tiny (thought to be viruses!) • Chlammydia trachomatis – trachoma (severe eye infection) and STD • Most frequently reported ID in the US – Georgia in top 5! (15 – 24 year old women) • C. pneumoniae – pneumonia

39. Photosynthetic bacteria • Green and Purple photosynthetic bacteria – do not produce O2; have bacteriochlorophyll; anaerobic; use H2S or S in their metbolism • Cyanobacteria. Chlorophyll a and other pigments; thylakoids to increase surface area; blue-green pigment is phycocyanin • great ecological importance in the global carbon, oxygen and nitrogen cycles

40. Photosynthetic bacteria Cyanobacteria Anabaena with heterocyst, a specialized cell for nitrogen fixation. The large bright cell in the filament is a type of spore called an akinete Synechococcus –marine; 25% of primary production OscillatoriaNostoc

41. Photosynthetic bacteria Colonial (with gelatinous sheath) filamentous PURPLE SULFUR BACTERIA CYANOBACTERIA

42. Archaea – the “other” prokaryotes • constitute third Domain Archaea • more closely related to Eukarya than to bacteria • unique genetic sequences - rRNA • unique membrane lipids & cell wall

43. ________________: Based on their physiology, the Archaea can be organized into three types: ________________ -- prokaryotes that produce methane; obligate anaerobes extreme ____________-- live at very high concentrations of salt (NaCl) extreme (hyper) ________________ -- live at very high temperatures • Halophiles thrive in high salt environments • Use red pigments for ATP (energy) synthesis • “Red Sea”