The document details the characteristics and classifications of aerotolerant fermentative cocci, particularly focusing on various genera such as Streptococcus, Leuconostoc, and Pediococcus. It describes their metabolic processes, arrangements, hemolytic types, and clinical significance, providing specific examples of pathogenic species like Streptococcus pyogenes and Streptococcus pneumoniae. Additionally, it discusses anaerobic gram-positive cocci and non-spore forming rods, including their growth conditions and pathogenic roles.

1. GRAM -POSITIVE
BACTERIA
RAMZA RASHEED

2. Aerotolerant fermentative cocci:
 Definition:
Aerotolerant organisms cannot use oxygen for growth but are tolerate
its presence. use fermentation to produce ATP.
 Characteristics:
 They don’t possess cytochromes.
 The cells are arranged in pairs, chain or tetrads.
 They have only fermentative type of metabolism and don’t respire
 They can grow anaerobically or aerobically.
 Genera
1. Streptococcus
2. Leuconostoc
3. Pediococcus

3. Streptococcus:
 Characteristics:
 Gram positive cocci
 The cells are arranged in pairs or chains
 Catalase-negative
 Organisms are homofermentative
 Genus is usually considered aerotolerant
 Streptococci divided into categories known as Lancefield group
 This includes 𝛼, 𝛽 and 𝛾 hemolytic streptococci

4. Type of hemolysis:
 α-hemolysis:
 Partially hemolyzed red blood cells of certain species of animals
 Colonies are surrounded by cloudy appearance
 Colonies on blood agar plates are surrounded by a greenish-colored zone
 Enzymes produced by some streptococci such as S. pneumoniae
 β-hemolytic:
 Complete lysis of red blood cells
 Colonies are surrounded by clear
 And colorless zone that indicate the complete lysis of the erythrocytes
 γ-hemolytic:
 Also called non-hemolytic
 Partially decomposition of the hemoglobin of the red blood cell

5. α-hemolytic
β-hemolytic
γ-hemolytic

6. Species of streptococci
 Streptococcus pyogenes:
 β-hemolytic
 Lancefield group A
 Gram positive
 Spherical /ovoid cocci arranged in long chains
 Most clinically important species
 Causes:
 Streptococcal sore throat
 Scarlet fever
 Erysipelas
 Acute glomerulonephritis
 Rheumatic fever
 And other human infection
fogs

10. Streptococci mutans
 Non-hemolytic
 Not placed in any Lancefield group
 rod-like with chains
 Causes:
 subacute bacterial endocarditis
 dental caries (tooth decay)
 Inhabits the human oral cavity

12. Streptococci faecalis
 α-,β-, or non hemolytic
 Lancefield group D
 called enterococcus
 Occur normally in intestinal tracts of humans
and animals
 Causes:
 Endocarditis
 Urinary tract infection
 Meningitis
 and other infections in humans.

14. S. lactis and S. cremoris
 Lancefield group N
 They are harmless contaminants of milk and dairy products
 Causes:
 Rapid souring and curdling of milk
Because of this are widely used as starter culture in the
manufacture of buttermilk and cheese

15. Streptococcus pneumoniae
 α-hemolytic
 Not placed in any Lancefield group
 Colloquially called pneumococcus
 They are usually found in pairs
 Don’t form spores
 Non motile
 Capsulated
 Small oval shaped cells
 Has great clinical significance
 Causes:
 Lobar pneumonia in human
xnbn
mbnn

18. Leuconostoc
 Characteristics:
 Gram-positive bacteria
 generally ovoid cocci
 Cocci are arranged in pairs
and chains
 Catalase-negative
 Organisms are heterofermentative
 Leuconostoc are harmless
saprophytes
 Used in starter culture

19. Pediococcus
 Characteristics:
 Gram positive
 Lactic acid bacteria
 Cocci occur in pairs and tetrads
 Catalase-negative
 Hemolytic type of fermentative
 Pediococci are saprophytes
 Cause:
 Beer to become ropy and viscous

20. Anaerobic gram positive cocci
 These cocci have a fermentative type of metabolism
 Some genera supplied fermentative carbohydrates
 Some can ferment amino acid
 Most genera contain CO2, H2, short chain fatty acid and ethanol or
succinate acid

21. Genus Arrangements
of cells
Main sources of
carbon and
energy
Occurrence
Peptococc
us
Pairs, clusters,
tetrads, and short
or long chains
Peptone or amino
acids
Human intestine
and respiratory
tract;
Clinical specimens
Peptostrept
ococcus
Pair, short or long
chains
Peptone or amino
acids
Human clinical
specimens
Ruminoco
ccus
Pairs and short or
long chains
Carbohydrates Bovine and ovine
rumen; animal
ceca
Coprococc
us
Pairs and short or
long chains
Carbohydrates Human feces
Sarcina Cubical packets of
eight cells
Carbohydrates Soil; mud; cereals
grains; diseased
human stomachs

23. Non spore forming gram positive rods of
regular shape:
 Heterogenous group
 Parasitic and pathogenic organism
 Long rods to very short rods
 E.g. lactobacillus
 One genus Caryophanon
 Composed of large disk shaped
arranged in trichomes

24. Non spore forming irregular shape
 Straight and slightly curved rod
 May be club shape
 Anaerobic or facultative anaerobes
in nature
 Examples:
1) Corynebacterium
 Rod shaped cells
 May be pleiomorphic(change according to environment)
 Cells accumulate intracellular granules
 Formed by complex of inorganic phosphates
 Stains are reddish purple or dilute methylene blue
 Cells are mycolic acids which contain about 32-36 carbon atoms

25.  Arthrobacter:
 Rod coccus cycle cell long phase of growth
 irregularly shaped rods
 In contrast stationary phase growth are distinctly
coccoid
 When these are inoculated into fresh media
 Brevibacterium
 Exhibit rod coccus cycle
 Only recognized species β linens from orange colony and salt tolerant
 Micro bacterium :
 Small slender irregular shaped
 Don’t exhibit rod coccus cycle

26.  Occur in milk and dairy products
 Cellulomonas:
 Irregular shaped rods
 Functions:
 degrade the cellular
 Use as major carbon and energy
 Aerobic filamentous
Formed colonies to mircoscopic size
 Branched filaments
 Develop to macroscopic cell

27.  Parasite and pathogenic for human and animals
 Belong to causative agents
 Anaerobic non filaments:
 Diff by their morphology
 And their fermentation and products
 2 Genera:
 Propionibacterium
 Actinomyces

28. Thank you