Gram Positive, Spore-Forming Bacteria

Bacillus anthracis


 

a. Morphologic and Physiologic Description - gram-positive, spore-forming rod, non-motile, aerobic, encapsulated, ferments carbohydrates
 
b. Pertinent Taxonomy - none
 
c. Host Range - cattle, sheep, horses, swine, other species less frequently. Man is susceptible
 
d. Source - soil, contaminated carcasses and certain animal feed products (bone meal)
 
e. Virulence Factors:
   - capsule
   - exotoxin: composed of three components: components
      * edema factor (EF)
      * protective antigen (PA)
      * lethal factor (LF): produces edema and shock
 
f. Resistance - no major antibacterial drug resistance problems. Spores make elimination of the organism from the premises very difficult
 
g. Available Biologicals - live spore vaccines developed from avirulent unencapsulated strains

Bacillus periformis


 

a. Host Range - laboratory rodents, foals, several other species
 
b. Source - Gl tract, soil, bedding

Bacillus cereus


 

a. Host Range - dairy cattle, man
 
b. Source - soil, vegetation

Clostridium botulinum


 

a. Morphology and Physiology - gram positive spore-forming anaerobic rod; motile; ferments carbohydrates
 
b. Pertinent Taxonomy - none
 
c. Host Range - horses, dogs, cattle, chickens, ducks, turkeys, man, and other animals
 
d. Source - soil, vegetation, digestive tract of animals and man
 
e. Virulence Factors - neurotoxins - 6 different types labeled A, B, C, D, E, F
 
f. Resistance - Spores are resistant in the environment. The organism is not particularly resistant to antibiotics.
 
g. Available Biologicals - Toxoids are available but not widely used.

Clostridium chauvoei


 

a. Morphologic and Physiologic Description - gram-positive spore-forming rod, motile, anaerobic, fermentative
 
b. Pertinent Taxonomy - also called Clostridium feseri; closely related to Clostridium septicum
 
c. Host Range - cattle and sheep primarily
 
d. Source - soil
 
e. Virulence Factors - produces exotoxin with the following components:
   - Alpha- neurotoxin, dermonecrotic, fibrinolytic, hemolytic
   - Beta - deoxyribonuclease
   - Gamma- hyaluronidase Delta - hemolytic
 
f. Resistance - no major antibacterial resistance. Spores are resistant in the environment
 
g. Available Biologicals - commercial bacterins are available

Clostridium haemolyticum


 

a. Morphologic and Physiologic Description - gram-positive spore-forming rod, motile, anaerobic, fermentative
 
b. Pertinent Taxonomy - also known as Clostridium novyii or oedematiens type D
 
c. Host Range - primarily cattle and sheep
 
d. Source - soil
 
e. Virulence Factors - produces beta exotoxin of novyii complex which is lethal, necrotizing, hemolytic and has lecithinase activity
 
f. Resistance - no major antibacterial drug resistance problems. Spores are resistant in the environment
 
g. Available Biologicals - commercial bacterins are available

Clostridium novyii


 

a. Morphologic and Physiologic Description - gram-positive spore-forming rod, motile, anaerobic, fermentative
 
b. Pertinent Taxonomy - called Clostridium oedematiens by the British
 
c. Host Range - cattle and sheep primarily
 
d. Source - soil
 
e. Virulence Factors - three exotoxins are produced and are the basis for separating the organism into types A-D:
   - Alpha - lethal, necrotizing
   - Beta - lethal, necrotizing, hemolytic, lecithinase
   - Gamma - necrotizing, lecithinase, hemolytic
 
f. Resistance - no major antibacterial drug resistance. Spores are resistant in the environment
 
g. Available Biologicals - commercial bacterins are available

Clostridium perfringens


 

a. Morphologic and Physiologic Description - gram-positive spore-forming (not readily formed in the laboratory) rod, non-motile, encapsulated, anaerobic, fermentative
 
b. Pertinent Taxonomy - also known as Clostridium welchii
 
c. Host Range - cattle, sheep, horses, swine, dogs, man
 
d. Source - widely distributed in the environment, also present in the digestive tract of man and animals
 
e. Virulence Factors:
   - capsule
   - 12 exotoxins are produced which provide a basis for separating the organism into five distinct types: A,B,C,D,E.
   - Toxins:
      * Alpha - lethal, this is a lecithinase, also produces hemolysis
      * Beta - lethal and necrotizing
      * Gamma - lethal, hemolytic
      * Delta - lethal, hemolytic
      * Epsilon - lethal and necrotizing
      * Eta - lethal
      * Theta - lethal, hemolytic
      * Iota - lethal, necrotizing
      * Kappa - collagenase
      * Lambda - collagenase
      * Mu - hyaluronidase
      * Nu - deoxyribonuclease, leukocidin
      * An enterotoxin which is associated with secretory diarrhea is also produced
 
f. Resistance - no major antibacterial drug resistance. Spores are resistant in the environment
 
g. Available Biologicals - commercial bacterins and toxoids are available
 
h. Miscellaneous - considered to be the most ubiquitous of the anaerobes

Clostridium tetani


 

a. Morphology and Physiology - gram positive, spore-forming anaerobic rod, motile, does not attack carbohydrates; spores are terminal, giving the cells a classical "tennis-racket" appearance.
 
b. Pertinent Taxonomy - none
 
c. Host Range - horses, cattle, sheep, goats, pigs, dogs, cats, and man
 
d. Source - spores are primarily found in soil which has been contaminated with human or animal feces.
 
e. Virulence Factors - tetanospasmin - neurotoxin; tetanolysin hemolysin
 
f. Resistance - spores are resistant; organism will persist in the environment. Organism is not highly resistant to antibiotics.
 
g. Available Biologicals - tetanus antitoxin, tetanus toxoid

Clostridium septicum


 

a. Morphologic and Physiologic Description - gram-positive spore-forming rods, motile, anaerobic, fermentative
 
b. Pertinent Taxonomy - the British suspect that the organism may be a subtype of Clostridium chauvoei because of their similarities
 
c. Host Range - cattle, horses, sheep, swine, and man
 
d. Source - soil, digestive tract of herbivores
 
e. Virulence Factors - produces four toxic components (exotoxins):
   - Alpha- lethal, necrotizing and hemolytic
   - Beta - deoxyribonuclease and leukocidin
   - Gamma- hyaluronidase
   - Delta - hemolytic and necrotizing
 
f. Resistance - no major antibacterial drug resistance problems. Spores are resistant to environmental factors
 
g. Available Biologicals - commercial bacterins are available

Clostridium sordelli


 

a. Morphologic and Physiologic Description - gram-positive spore-forming rod, motile, anaerobic, fermentative
 
b. Pertinent Taxonomy - also known as Clostridium bifermentans c. Host Range - cattle, sheep, horses d. Source - soil e. Virulence Factors - exotoxin - lethal, necrotizing
 
f. Resistance - no major antibacterial drug resistance problems. Spores are resistant in the environment
 
g. Available Biologicals - commercial bacterins are available

Gram Positive, Non-Spore-Forming Bacteria

Beta-Hemolytic Streptococci


 

a. Morphologic Appearance - Gram positive cocci in pairs and long chains, non-motile, encapsulated, facultative .
 
b. Pertinent Taxonomy - divided into alphabetically designated serologic groups based on specific carbohydrate in cell wall (Lancefield grouping).
   - Group A
      * Streptococcus pyogenes
   - Group B
      * Streptococcus agalactiae
   - Group C
      * Streptococcus equi
      * Streptococcus equisimilis
      * Streptococcus zooepidemicus
      * Streptococcus dysgalactiae
   - Group G
      * Streptococcus canis
 
c. Host Range
   - Streptococcus pyogenes - man, dogs, cattle
   - Streptococcus agalactiae - cattle, man
   - Streptococcus equi - horses
   - Streptococcus equisimilis - horses, swine, man, cattle
   - Streptococcus zooepidemicus - horses, swine, cattle, poultry, man
   - Streptococcus dysgalactiae - cattle
   - Streptococcus canis - dogs, cattle, cats, man
 
d. Source - upper respiratory tract, lower urogenital tract, skin, mammary gland.
 
e. Virulence Factors
   - Streptolysins
   - Capsule (hyaluronic acid)
   - Streptokinase fibrinolysin)
   - Streptodornase (DNAase)
   - Hyaluronidase
   - Reversion to L form?
   - Wall antigens?
 
f. Resistance - relatively fragile in the environment; resistance to antibiotics does not develop rapidly.
 
g. Available Biologicals - Streptococcus equi and Streptococcus zooepidemicus are available as bacterins, commercial or autogenous.

Rhodococcus equi


 

a. Morphologic Description - gram positive pleomorphic, non-spore-forming rod, non-motile, aerobic, non-fermentor of carbohydrates
 
b. Pertinent Taxonomy - formerly called Corynebacterium equi.
 
c. Host Range - primarily equines, especially young foals, occasionally swine
 
d. Source - considered to be a soil-borne organism, but can be recovered from normal animals also
 
e. Virulence Factors - encapsulated, facultatively intracellular. Toxins? - Equi factor?
 
f. Resistance - increasing resistance to antibacterial drugs has been noted over the last ten years
 
g. Available Biologicals - no commercial products. Autogenous bacterins have been used with some success
 
h. Miscellaneous - individual herd or premises problem

Corynebacterium pseudotuberculosis


 

a. Morphologic Appearance - gram positive, pleomorphic, non-spore-forming rod,; nonmotile, not encapsulated, facultative, fermentative
 
b. Pertinent Taxonomy - many people call the organism Corynebacterium ovis
 
c. Host Range - sheep, horses, other animals on occasion
 
d. Source - soil-borne?, may be vector transmitted, carrier animals have also been incriminated
 
e. Virulence Factors
   - facultatively intracellular
   - exotoxin (hemolysin?)
   - cell wall antigens
 
f. Resistance - not markedly resistant to antibiotics, can survive in soil
 
g. Available Biologicals - there has been minimal production of autogenous or commercial bacterins

Erysipelothrix rhusiopathiae


 

a. Morphology and Physiology - gram positive, non-spore-forming rod, often filamentous, nonmotile, fermentative
 
b. Pertinent taxonomy - Erysipelothrix insidiosa
 
c. Host Range - pigs, sheep, cattle, turkeys and other avian species, marine mammals, man (erysipeloid)
 
d. Source - infected animals, carriers, soil, putrefying materials
 
e. Virulence Factors - probably exotoxins but not well characterized
 
f. Resistance - fairly resistant to environmental factors; not particularly resistant to antibiotics
 
g. Available Biologicals - bacterins, modified live vaccines

Listeria monocytogenes


 

a. Morphology and Physiology - gram-positive, non-spore-forming rod, facultative, motile at room temperature, encapsulated under special conditions, fermentative
 
b. Pertinent Taxonomy - 12-15 serologically distinct varieties. No difference noted between human and animal isolates
 
c. Host Range - several mammals, birds, fish, man
 
d. Source - sewage, silage, milk, feces, soil
 
e. Virulence Factors
   - facultatively intracellular
   - hemolysin (cytotoxic)
   - lipid (evokes monocytosis)
   - invasiveness
 
f. Resistance - fairly resistant to environmental factors. Not highly susceptible to antimicrobials
 
g. Available Biologicals - none

Staphylococcus aureus


 

a. Morphology and Physiology - gram positive cocci, nonmotile, sometimes encapsulated, facultative, fermentative
 
b. Pertinent Taxonomy - none
 
c. Host Range - dogs, cats, cattle, horses, swine, birds, man
 
d. Source - ubiquitous; may reside in nasal passages, skin, or other mucous membranes
 
e. Virulence Factors
   - capsule
   - protein A
   - bound coagulase
   - free coagulase
   - hemolysins - alpha, beta, delta, gamma
   - leukocidin
   - enterotoxin - A through D
   - epidermolytic toxins (epidermolysins, exfoliatins)
   - staphylokinase (fibrinolysin)
   - hyaluronidase
   - deoxyribonuclease (DNAase)
   - toxic shock syndrome toxin 1
 
f. Resistance - probably the most resistant of the non-spore-forming bacteria to environmental factors. Increasing resistance to antibiotics has been observed, both plasmid mediated and chromosomal
 
g. Available Biologicals - relatively few commercial products; autogenous bacterins frequently used for some conditions