bacteriology is a bit confusing thing while studying. here it now a easy way for study all the types.

2. Manu Aravind

3. STAPHYLOCOCCUS
Staphylococcus is a genus of Gram-
positive bacteria. Under the microscope,
they appear round (cocci),non motile
arranged in groups and form in grape-
like clusters. Staphylococcus can cause
a wide variety of diseases in humans
and animals through either toxin
production or penetration.
Staphylococcal toxins are a common
cause of food poisoning.

4. CLASSIFICATION
On the basis of pigment production
mainly 3 types.
 Staphylococcus aureus ( produces
golden yellow colonies)
 Staphylococcus albus ( produces white
colonies )
 Staphylococcus citerus ( produces
lemon yellow colonies )

5. CLASSIFICATION
 On the basis of pathogenecity
 Pathogenic species - Staphylococcus
aureus
 Non pathogenic species –
Staphylococcus epidermidis

6. RESISTANCE :
 It is the more resistant among non-
sporing organisms.
 It withstands 600C for 30 min
 It resist 1% phenol for 15 min
 Mercury perchloride (1%) kills it in 10
min
 Crystal violet and brilliant green are
lethal for it
 Staphylococci are resistant to penicillin.

7. STREPTOCOCCUS
They are gram positive cocci arranged in
chains , non motile and non sporing.
The require media enriched with blood ,
serum or ascetic fluid for their growth.
They are important human pathogens
causing pathogenic infection with a
characteristic tendency to spread.

8. CLASSIFICATION
Morphological
classification
 Long chains –
Pathogenic
 Short chains - Non
pathogenic
 Based on cultural
character
 Anaerobe
 Aerobes

9. CLASSIFICATION
 Aerobes – the aerobic streptococci are
further classified on the basis of
haemolytic property on blood agar
plates.
 Alpha haemolytic - produces a zone of
greenish discoloration around the
colony.
 Beta haemolytic – produces sharply
defined , clear , colourless zone of
haemolysis.

10. RESISTANCE :
o it is easily destroyed by heat @ 560 C
for 80 min.
 It can survive in dust for several weeks if
protected from sunlight
 It is resistant to crystal violet.

11. PNEUMOCOCCUS
 They are gram positive diplococcic and
are capsulated. Pneumococci primary
occur in human throat and are the most
common cause of pneumonia. They
require enriched medium with blood ,
serum or ascetic fluid for their growth.

12. MORPHOLOGY
It is typically small and slightly elongated
with one end broad and other end
pointed (flame shaped ). It occurs in
pairs. It is capsulated , capsules
enclosing both pair. It is non motile and
non sporing.

13. RESISTANCE :
It is readily destroyed by heat 520C for 15
min., in 1 hr by phenol , potassium
permanganate and other antiseptics.

14. CULTURAL
CHARACTERISTICS
It requires serum or whole blood for
growth. It grows best at 370C and at
PH7.6. it is aerobic. growth is improved
by providing them 5 to 10% CO2.

15. BACILLUS
They are rode shaped sporogenous.
classified into two groups.
 Aerobic bacillus
 Anerobic basillus
Aerobic bacillus
 They are gram positive , non motile ,
spore bearing bacillus occurring in
chains.
 Eg. Bacillus anthrax

16. BACILLUS ANTHRAX
 It is non motile , non acid fast , gram
positive bacilli. They may be arranged
singly or in short chains. The entire
chain may be surrounded by capsule.
Spores are formed in soil only in
presence of oxygen and not in animal
body. It remains in parasitic form in
cattle and sheep. Infection in man is the
result of accidental contact with the
infected animals.

17. CULTURAL
CHARACTERISTICS
 It is aerobic growing at optimum
temperature of 370C. The optimum
temperature for spore formation is 25-
300C. growth may occur in ordinary
medium.

18. RESISTANCE
 Vegetative form is killed within 30 min @
560C. Anthrax spores remains viable for
years in dry state. Dry heat @400C
requires 3 hrs and steam5-20 min for
sterilization. They survive in 5% phenol for
weeks. They are killed in 4% potassium
permanganate and destroyed in 2%
formaldehyde, they are susceptible to
penicillin , sulphonamide , erythromycin ,
streptomycin , tetracycline and
chloramphenicol.

19. Route of infection in man.
 There are mainly 3 routes of infection.
 Through skin
 Pulmonary anthrax
 Intestinal anthrax

20. CLOSTRIDIUM
 They are gram positive , anaerobic ,
spore forming , spindle shaped highly
pleomorphic bacilli. Spores are wider
than the bacillary body. The genus
containing bacteria will cause diseases
mainly like tetanus, food poisoning etc.

21. Cultural characteristics.
 It is an anaerobe and grows only in
absence of oxygen. The optimum
temperature required is 370C and pH 7.4.
it grows fairly well in ordinary media

22. RESISTANCE
 Spores of clostridium tetani withstand
boiling for 15-90 min. autoclaving
@1210C for 20 min kills spores.. spores
otherwise can survive in soil for yrs.
Iodine (1% aqueous solution) and H2O2
kills spores within a few min.