Staphylococcus is a genus of gram-positive, non-motile cocci arranged in grape-like clusters, commonly found on the skin and mucous membranes of mammals and birds. They possess various virulence factors and are known for causing several infections, including bovine mastitis and pyoderma in pets. Diagnosis involves culture methods, biochemical tests, and antimicrobial treatments may vary, with resistance being a significant concern.

1. Staphylococcus
 Spherical cells
 arranged in grapes like clusters
 Gram positive
 non-motile
 non-acid fast and non-spore forming
 aerobic and facultative anaerobic
 Most strains form pigments
 positive for catalase, coagulase
 Negative for oxidase

2. History
 Ogston (1883) introduced the name
Staphylococcus (a bunch of grapes) for the
group-micrococci causing inflammation and
suppuration.
 Rosenbach (1884) – described the genus
Staphylococcus, dividing the genus into the two
species Staphylococcus aureus and S. albus.

3. Habitat and Ecology
 occurs worldwide in mammals and birds on skin
and mucous membranes
 Found in the pharynx, mouth, blood, mammary
glands, and intestinal, genitourinary, and upper
respiratory tracts of these hosts
 Opportunist

4. Morphology
 Cocci
 Gram positive
 cells occur in clusters (bunches of grapes) Pairs and short
chains are seen frequently in fluid media.
 non spore formers
 non-motile
 non-capsulated (some in clinical material possess a
polysaccharide capsule )

5. Cultural characteristics
 Aerobic and facultatively anaerobic.
 optimum temperature of 35-37°C.
 Grow very well in the presence of 7-10% Sodium chloride.
 Mannitol salt agar - most preferred medium
 medium to large, mucoid, pigmented, entire, round colonies
on blood agar.
 Bovine blood agar- double zone (hot cold) haemolysis and 
haemolysis.
.

6. Staphylococcus on Nutrient Agar
Nutrient agar: white, yellow, or orange
water-soluble pigments

7. Staphylococcus aureus Growing on Mannitol Salt Agar
Acid from mannitol fermentation
causes the pH indicator phenol
red to turn from red (alkaline) to
yellow (acid).
Mannitol salt agar - selective
for staphylococci because of the
high salt concentration.
Test
Staphylococcus
aureus
Staphylococcus
epidermidis
Staphylococcus
saprophyticus
mannitol
fermentation
positive negative usually positive

8. Growth on blood agar- double zone lysis-hot cold lysis
S. aureus S. epidermidis

9. Bio-chemical properties
 Oxidase negative and catalase & coagulase positive
 produces acid from glucose maltose, mannitol, lactose
and sucrose and not from salicin, raffinose & inulin.
 Hydrolyses gelatin and coagulate serum.
 Negative for H2S production.

10. Resistance
 Most resistant cocci.
 Resistant to disinfectants including phenolic
compounds and can withstand a high salt
concentration
 60°C for half an hour destroys all the cells.
 Killed in 1% phenol in 35 minutes or 10%
formaldehyde in 10 minutes.
 Resistant to penicillin due to their ability to
produce penicillinase

11. Virulence Factors
 Three groups of virulence factors
 Surface components : Protein A, Cell wall,
Capsule
 Exotoxins :
 Hemolysin (Alpha, Beta, delta and Epsilon toxin),
 Leukotoxin,
 Enterotoxin (heat stable, not destroyed at 100°C for 80
minutes), Dermonecrotoxin, Toxic shock syndrome
toxin
 Extracellular enzymes Coagulase (CPS)
Hyaluronidase, Nucleases, Fibrinolysin
Lipases & esterase, Lysozyme and
Penicillinase

12. Pathogenesis
Capsules
Normal inhabitant  Tissue damage antiphagocytoic
Protein A activity.
Establishment
of staphylococci Protect bacteria Tissue damage
coagulase Extracellular
Enzymes

13. Cow: Mastitis
 S. aureus - most important cause of bovine mastitis in dairy herds
worldwide. (On occasions- S. intermedius).
 S. epidermidis - subclinical mastitis.
 Staphylococcal bovine mastitis - chronic, acute and peracute.
Gangrenous mastitis due to  toxin is seen in postparturient cows.
 Causes severe damage to milk producing tissue. Often causes abscess
formation.
 The alpha toxin causes vasoconstriction and ischemia to the udder
resulting in gangrene. Gangrenous mastitis causes a patchy blue
discoloration, and coldness of the tissue and leaking of blood serum
through the skin.
 Also causes subclinical mastitis and results in a herd mastitis problem.

15. Tenosynovitis
MALMARUGAN, 2015
Bumble foot in poultry
Pyogranulomatous
process of
subcutaneous
tissue of foot

16. wing rot or gangrenous dermatitis

17. Greasy pig disease –Exudative Dermatitis
Sta. hyicus : excess
sebaceous secretion,
exfoliation and exudation
Ritter's disease in baby
– S.aureus

18. Horse
 Botryomycosis: Infrequent chronic
granulomatous lesions involving the
spermatic cord of male horses.
Sheep
 Tick pyemia in lambs -2-5 week old
lambs (heavily infected with Ixodes
ricinus)
 Periorbital eczema is an infection
due to abrasion
 Staphylococcal dermatitis due to
scratches from vegetation
Dogs and Cats: Pyoderma, Otitis externa
and other suppurative conditions caused
by Sta. intermedius.

19. Diagnosis
Materials for diagnosis
 Pus, affected tissue and milk samples.
Examination of culture and pus smear
 Grams staining reveal Gram-positive organisms with typical
arrangement.
Isolation and identification by culture method:
 Organisms grow well in ordinary laboratory media.
 Most preferred media - mannitol salt agar.
 Blood agar -primary isolation - round, smooth, glistening
and may or may not have golden yellow pigments.
 Produce double zone haemolysis and  haemolysis.
 Haemolysis is best demonstrated in bovine red blood cells.

20.  Coagulase test: To a loopful of bacterial culture in saline
a drop of rabbit plasma is added over a slide.
Appearance of clumps within ten minutes is considered
as positive.
 Most of the Staphylococci produce coagulase enzyme,
coagulase converting fibrinogen into fibrin promoting
blood clotting.
Diagnosis contd..
Coagulase - Tube test
Coagulase - Slide test

21.  Hotis test – slightly acid rust color colonies
Diagnosis contd..

22.  Latex agglutination test
 Phage typing
 Biochemical tests: oxidase test, coagulase test,
beta haemolysis, pigment production, utilisation
of maltose and mannitol and sensitivity to
novobiocin.
Diagnosis contd..

23. Treatment
 Acute individual or sporadic cases could be treated
with effective antimicrobial.
 Cloxacillin is effective in treatment of
staphylococcal mastitis in dry cows on a herd
basis.
 Other drugs that are effective against
staphylococcal infections in animals are
chloramphenicol, erythromycin, cephalosporin,
vancomycin, lincomycin and trimethoprim sulfas.
 Methicillin resistance is indicative of multiple
resistance