Staphylococci is the gram +ve cocci having size 1 µm
in diameter and mostly arranged in irregular grape like structure. Greek word: styphale
= bunches of grapes kokkos
= berry they are Opportunistic
bacteria. In 1871-Von Recklinghausen first observed staphylococci in human
pyogenic bacteria. In 1880-Sir
Alexander Ogston named staphylococci. It comprises about 40 species and
Staphylococci are facultative anaerobes, catalase positive,
non-motile, oxidase negative and do not forms spore (except S.saccharolyticus).
Peptidoglycan and protein A is the major component of the cell wall and
teichoic acid also present. Unique property of the protein A is to bind to Fc
part of the IgG3.On the basis of enzyme coagulase there are 2 groups:
1.coagulase positive e.g. S.aureus,
2.coagulase negative: e.g. S.haemolyticus
It can be grow readily on ordinary media. It requires optimum
tempereture: 37°C, pH-(7.4-7.6) & aerobe and facultative anaerobe. Colony
morphology is large 2-4 mm, circular, convex, smooth & opaque.The colonies produce
by staphylococci is golden yellow colony on nutrient agar (oil paint appearance). On the blood agar
it produces hemolytic or non-hemolytic colonies.It also grows on Mannitol salt
Methyl red test
Modified oxidase test
Coagulase test: Suspension of
staphylococci is mixed with rabbit plasma. The coagulase enzyme secreted by
bacteria covert the fibrinogen of the rabbit plasma to fibrin and clotting
A. slide test: Detect bound coagulase or
clumping factor on bacterial surface. Then clumping occurs in 1-2 min
test: Detect coagulase which is secreted by bacteria in plasma. Then clotting
occurs after incubation at 37 °C for 24 hrs.
Staphylococci are commensales
on skin of animals and man. Isolated commonly from mucus membrane of upper
respiratory tract and lower urogenital tract & transient digestive tract. Selective
affinity to species of animal.
PATHOGENESIS AND PATHOGENECITY
Staphylococci are the pyogenic bacteria mainly in suppurative
lesions.Minor trauma or immunosuppresion may predispose the development of infection.
Structural features like capsular polysaccharides, teichoic acid and protein A
interfere with opsonization and subsequent phagocytosis. Coagulase – major
indicator of pathogeneity.
Mastitis, udder impetigo
Botryomycosis of mammary
Scirrhous cord, mastitis
Bumble foot , omphalitis
Various pyogenic conditions
material from exudates &mastitis milk. Gram stained smear from pus. Culture
on blood agar, selective blood agar and Mc Conkey’s agar and incubated
aerobically at 37°C for 24 -48 hrs.
ü Colonial characteristics
ü Growth on Mc Conkey´s agar
ü Biochemical procedure