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

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Survey of MicrobesPart I Important
prokaryotesGram negative organisms, archaea,
and others
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IMPORTANT GRAM NEGATIVE PROTEOBACTERIA
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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?

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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)

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PID

• 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

• 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
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Figure 23. Gonorrhea Positivity among 15- to
24-year-old women tested in family planning
clinics by state United States and outlying
areas, 2007
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Gram negative rods
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Enterobacteriaceae shared characteristics
Gram - rods

• ____________________ 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)

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

• 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 ________________
  ________________________________

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Pathogenesis
Gram - rods

• 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

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G- bacilli Enterobacteriaceae
Gram - rods

• _________(strain O157H7) 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
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Some toxins produced by enteric bacteria
Gram - rods

• ______________(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)

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A quick note on diarrhea

• Travellers 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).

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Other important Enterobacteriaceae
G- bacilli

• 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

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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)

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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

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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
• gt80 ulcers are Hp!

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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/nc
  idod/dvrd/qfever/)

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Spots due to small hemorrhages
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Other phyla of prokaryotes

• Chlammydias, Spirochetes, Photosynthetic
  bacteria, Archaea (extremophiles)

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Spirochetes
Borrelia burgdorferi
Treponema pallidum
Cross section

• 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

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Syphillis
Spirochetes Treponema pallidum

• 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

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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

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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

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Cyanobacteria
Photosynthetic bacteria
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
Oscillatoria Nostoc
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Photosynthetic bacteria
Colonial (with gelatinous sheath)
filamentous
PURPLE SULFUR BACTERIA
CYANOBACTERIA
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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

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• ________________
• 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