Chapter 11- Bacteria
I. Phylum: Proteobacteria
A. Class: a-proteobacteria
1. Order: Rickettsiales
a. Genus: Ehrlichia
i. Gram-negative rod or coccobacilli
ii. Intracellular pathogens that live in white blood cells
iii. Transmitted to humans by ticks, cause erlichiosis
b.
Genus: Rickettsia
i. Gram-negative rod or coccobacilli.
ii. Enter the cell by induced phagocytosis, escaping into the cytoplasm
iii. Species
a. R. prowazekii typhus transmitted by lice
b. R. typhi typhus transmitted by fleas
c. R. rickettsii Rocky Mountain Spotted Fever, transmitted by ticks.
2. Order: Rhizobiales
a.
Genus: Bartonella
i. Gram-negative bacillus
ii. B. henselae causative agent of Cat Scratch Fever
b.
Genus: Brucella
i. Small nonmotile Gram-negative coccobacilli
ii. Cause brucellosis, and survive phagocytosis
B. Class: b-proteobacteria
1. Order: Burkholderiales
a. Genus: Burkholderia
i. Formerly grouped with the Pseudomonas
ii. Gram-negative, motile bacillus
iii. Species
a. B. cepacia common hospital acquired infections resulting from its ability to grow in very diverse conditions.
b. B. pseudomallei causes melioidosis, endemic to SE Asia and Australia
b.
Genus: Bordetella
i. Nonmotile aerobic Gram-negative bacillus
ii. B. pertussis causative agent of pertussis, whopping cough.
2. Order: Neisseriales
a.
Genus: Neisseria
i. Gram-negative diplococci
ii. Species
a. N. gonorrhoeae sexually transmitted disease
b. N. meningitides agent of meningitis
C. Class: g-proteobacteria
1. Order: Thiotrichales
a.
Genus: Francisella
i. Small, pleomorphic bacteria that only grow on complex media
supplemented with things such as blood.
ii. F. tularensis causative agent of tularemia, a prospective bioweapon with a very low infective dose.
2. Order: Legionellales
a.
Genus: Legionella
i. Gram-negative bacillus
ii. Common in aquatic environments (i.e. AC units)
iii. Intracellular pathogens
iv. L. pneumophilia causes legionellosis (Legionnaires disease)
b.
Genus: Coxiella
i. Intracellular pathogen
ii. Transmitted by air or contaminated milk
iii. Produces a spore-like body that is resistant to insult
iv. C. burnetti causes Q fever
3. Order: Pseudomonadales
a.
Genus: Moraxella
i. Strictly aerobic coccobacillus
ii. Infectious agent in conjunctivitus
b.
Genus: Pseudomonas
i. Motile, Gram-negative, motile bacillus
ii. Very nutritionally diverse
iii. Opportunistic pathogens
iv. High level of antibiotic resistance present.
4. Order: Vibrionales
a.
Genus: Vibrio
i. Slightly curved, gram-negative bacillus
ii. Species
a. V. cholerae cholera
b. V. parahaemolyticus gastrointestinal pathogen, common in shellfish.
5. Order: Enterobacteriales (enterics food poisoning)
a. Genus: Citrobacter
b. Genus: Enterobacter
c.
Genus: Escherichia
1. E. coli potential food poisoning organism, and classical model system
d.
Genus: Klebsiella
1. K. pneumoniae causes a potentially fatal form of pneumonia.
e.
Genus: Proteus
1. Easy to distinguish on plates from its swarming behavior
f. Genus: Salmonella
g. Genus: Serratia
h. Genus: Shigella
i.
Genus: Yersinia
1. Y. pestis causative agent of bubonic plague, a potential bioweapon and the most likely disease that caused the Black Death of European history (resulting in the death of close to half the population of Europe)
6. Order: Pasteurellales
a.
Genus: Haemophilus
1. H. influenzae causes a type of pneumonia, meningitis, and earaches.
2. H. ducreyi causes the sexually disease Chancroid.
b. Genus: Pasteurella
1. Causes sepsis and fowl cholera
D. Class: d-proteobacteria
1. Order: Bdellovibrionales
a.
Genus:
Bdellovibrio
i. A bacteria that preys on other bacteria but entering into their periplasm and digesting them.
E. Class: e-proteobacteria
1. Order: Campylobacterales
a.
Genus: Campylobacter
i. Motile, microaerophilic vibrios
ii. C. fetus causes abortions in livestocks
iii. C. jejuni is one of the leading causes of foodborne illness.
b. Genus:
Helicobacter
i. Motile, microaerophilic vibrios
ii. Survives the acids in the human stomach
iii. H. pylori causative agent of stomach ulcers
II. Phylum: Firmicutes (Low GC Gram-Positive Bacteria)
A. Order: Clostridiales
1.
Genus: Clostridium
A. Endospore forming anaerobic bacillus
B. C. tetani tetanus, rigid paralysis
C. C. botulinum botulism, flaccid paralysis
D. C. perfigens common cause of gangrene
B. Order: Mycoplasmatales
1.
Genus: Mycoplasma
A. Wall-less bacteria, highly pleomorphic
B. Very small, ranging from 0.1 to 0.25 mm
C. M. pneumoniae mild form of pneumonia
C. Order: Bacillales
1.
Genus: Bacillus
A. Endospore forming, aerobic bacillus
B. B. anthracis causative agent of anthrax, a potential bioweapon used in the 2001 mail attacks.
2.
Genus: Listeria
A. Aerobic bacillus
B. L. monocytogenes psychrophile that contaminates food
3.
Genus: Staphylococcus
A. Grape Clusters
B. S. aureus quickly develops resistance to antibiotics and can invade tissues
D. Order: Lactobacillales
1.
Genus: Enterococcus
A. Gram-positive cocci
B. Hardy organisms that reside in stool and are common contaminants on surfaces.
C. Highly resistant to most antibiotics
2. Genus: Streptococcus
A. Gram-positive cocci that appear in chains
B. Produce a number of exotoxins (toxins excreted from the cell)
C. Responsible for a number of diseases including strep throat (S. pyogens) and pneumonia (S. pneumoniae)
3. Genus:
Lactobacillus
A. Gram-positive bacillus
B. Common commensal organisms in humans
C. Practically used for the production of many commercial foods.
III. Phylum: Actinobacteria (High GC Gram-Positive Bacteria)
A. Order: Actinomycetales
1.
Genus: Actinomyces
a. Facultative anaerobe, common in the mouth
b. A. israelii causes a tissue destroying disease called actinomycosis
2. Genus: Corynebacterium
a. Highly pleomorphic cells, commonly referred to as Chinese Character Morphology
b. C. diptheriae Diptheria (Whooping Cough)
3.
Genus: Gardnerella
a. Highly pleomorphic and gram-variable
b. G. vaginalis common cause of vaginitis
4.
Genus: Mycobacterium
a. Aerobic, gram-positive bacillus
b. Covered in a waxy layer of mycolic acid
c. Slow growth rate, as many as 6-8 weeks to grow in culture
d. Two important human pathogens
i. M. tuberculosis tuberculosis
ii. M. leprae - leprosy
5.
Genus: Norcardia
a. Similar to Actinomyces, producing rudimentary filaments
b. Pathogenic species produce mycolic acids
c. N. asteroides produces a persistent pulmonary infection.
6.
Genus: Streptomyces
a. Common soil bacterium that produces aerial filaments
b. Produces a number of antibiotics
c. Nearly 500 identified species
7. Genus: Propionibacterium
a. Produces propionic acid, used to make Swiss cheese
b. P. acnes implicated in the formation of acne
IV. Phylum: Chlamydiae
A. Order: Chlamydiales
1.
Genus: Chlamydia
a. C. trachomatis causes two distinct diseases
i. Nongonococcal urethritis the most prevalent STD in US.
ii. Trachoma preventable blindness in babies
2.
Genus: Chlamydiophila
a. C. psittaci causes psittacosis (common among bird-lovers)
b. C. pneumoniae causes a mild pneumonia
3. Both genera produce elementary bodies as the infective agents.
4. Both genera have a complex life-cycle allowing for differentiation
5. Intracellular pathogens, with direct human/human transmission
V. Phylum: Spirochaetes
A. Order: Spirochaetales
1.
Genus: Borriela
a. Cause relapsing fevers and Lyme disease
2. Genus:
Leptospira
a. Excreted in the urine of domesticated pets.
3.
Genus: Treponema
a. T. pallidum causes syphilis
4. Possess axial filaments (endoflagella) allowing for rapid movement
VI. Phylum: Bacteroidetes
A. Order: Bacteroidales
1.
Genus: Bacteriodes
a. Heavily contaminating feces
b. Frequent cause of wound infections
VII.
Phylum: Fusobacteria
A. Order: Fusobacteriales
1.
Genus: Fusobacterium
a. Pointed end bacteria
b. Common cause of dental abscesses