### microbacteria:

Meningococcal bacteria
* are susceptible to a number of antibiotics.
* cause disease only in susceptible persons
  - meningitis by attacking tissues covering the brain and spinal cord
* is carried in saliva or droplets from the nose of an infected person.

### microbacteria:

Mycobacteria
* are also a leading cause of infection in various domesticated animals and wildlife
  - important human pathogens
  - notorious for their resistance to antibiotics that kill most other bacteria
  - obligate aerobes, i.e. the bacilli require oxygen for growth
  - resistant to oxidative attack in phagolysosomes
  - responsible for diseases such as leprosy or tuberculosis
  - unusual because they are intracellular parasites
* can also cause skin lesions and open sores in amphibians
  - spread hematogenously to many organs when granulomas rupture into blood vessels
* have an outer membrane.
* represent a thriving and ingenious family in the microbial domain.

Negative bacteria
* Most negative bacteria grow on surfaces
  - have germination
* Some negative bacteria inhabit intestinal tracks

Nitrifying bacteria
* Most nitrifying bacteria are autotrophic, with carbon dioxide serving as their carbon source.
* are bacteria that breakdown organic waste into simple compounds.
* changes the ammonia form of nitrogen to nitrites and nitrates.
* convert ammonia to nitrate, which is easier for the plant to absorb.
* reproduce by binary division.
* settle on gravel and build colonies.
* take several hours to reproduce.
* work either at full capacity or drift into a resting phase.

Nostoc
* are filamentous cyanobacteria that can easily fix nitrogen.
* commune to sulfur dioxide, natural gas, and crude oil in Arctic Alaska.

Numerous bacteria
* are obligate parasites that have reduced genomes and depleted cellular function.
* can cause infections of the gastrointestinal tract of guinea pigs.
* live in the nose and mouth that are also exposed to the immune system.

Oral bacteria
* Many oral bacteria produce bacteriocins capable of lysing other organisms.
* Most oral bacteria play roles.
* Some oral bacteria enter bloodstreams.
* are highly specialised organisms.
* can cause dental plaque, gingivitis, periodontal disease, and halitosis.
* feed on sugar, producing plaque.

Parasitic bacteria
* Some parasitic bacteria are transmitted to humans.
* Some parasitic bacteria cause diseases
  - human diseases
  - severe diseases

### microbacteria:

Pathogenic bacteria
* Many pathogenic bacteria detect whether they are in a host by testing the availability of iron.
* Many pathogenic bacteria use pili to adhere to animal tissues
  - special secretion systems to deliver toxic proteins into host cells
* Most pathogenic bacteria cause death
  - produce poisons
* Most pathogenic bacteria use independent mechanisms
  - oxygen for their continued existence
* Most pathogenic bacteria use several independent mechanisms
* Some pathogenic bacteria are genetically very homogeneous, making strain discrimination difficult
  - surrounded by a capsule that make phagocytosis difficult
  - can survive pasteurization
* Some pathogenic bacteria enter noses
  - urethras
  - kill worms
* are also the cause of high infant mortality rates in developing countries
  - bacteria that can cause infection
  - in the minority among prokaryotes
* can easily penetrate
  - reproduce on a large scale and produce toxic substances for their host
* group name for the bacteria that are capable of causing illness.
* like to live in the particular conditions found in the human body.
* luxuriate in water with a slightly basic pH, like water found in Klamath Lake.
* require time to multiply in a warm, moist, high protein environment.