Staphylococcus.ppt veterinary microbiology

Veterinary microbiology
Staphylococcus
General bacteriology
Essay notes

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)introducedthename
Staphylococcus(abunchofgrapes)forthe
group-micrococcicausinginflammationand
suppuration.
Rosenbach(1884)–describedthegenus
Staphylococcus,dividingthegenusintothetwo
speciesStaphylococcusaureusandS.albus.

3. Habitat and Ecology
occursworldwideinmammalsandbirdsonskin
andmucousmembranes
Foundinthepharynx,mouth,blood,mammary
glands,andintestinal,genitourinary,andupper
respiratorytractsofthesehosts
Opportunist

4. Morphology
Cocci
Grampositive
cellsoccurinclusters(bunchesofgrapes)Pairsandshort
chainsareseenfrequentlyinfluidmedia.
nonsporeformers
non-motile
non-capsulated(someinclinicalmaterialpossessa
polysaccharidecapsule)

5. Cultural characteristics
Aerobicandfacultativelyanaerobic.
optimumtemperatureof35-37°C.
Growverywellinthepresenceof7-10%Sodiumchloride.
Mannitolsaltagar-mostpreferredmedium
mediumtolarge,mucoid,pigmented,entire,roundcolonies
onbloodagar.
Bovinebloodagar-doublezone(hotcold)haemolysisand
haemolysis.
.

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

7. Staphylococcus aureusGrowing on Mannitol Salt Agar
Acidfrommannitolfermentation
causesthepHindicatorphenol
redtoturnfromred(alkaline)to
yellow(acid).
Mannitolsaltagar-selective
forstaphylococcibecauseofthe
highsaltconcentration.
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
Oxidasenegativeandcatalase&coagulasepositive
producesacidfromglucosemaltose,mannitol,lactose
andsucroseandnotfromsalicin,raffinose&inulin.
Hydrolysesgelatinandcoagulateserum.
NegativeforH2Sproduction.

10. Resistance
Mostresistantcocci.
Resistanttodisinfectantsincludingphenolic
compoundsandcanwithstandahighsalt
concentration
60°Cforhalfanhourdestroysallthecells.
Killedin1%phenolin35minutesor10%
formaldehydein10minutes.
Resistanttopenicillinduetotheirabilityto
producepenicillinase

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-mostimportantcauseofbovinemastitisindairyherds
worldwide.(Onoccasions-S.intermedius).
 S.epidermidis-subclinicalmastitis.
 Staphylococcalbovinemastitis-chronic,acuteandperacute.
Gangrenousmastitisduetotoxinisseeninpostparturientcows.
 Causesseveredamagetomilkproducingtissue.Oftencausesabscess
formation.
 Thealphatoxincausesvasoconstrictionandischemiatotheudder
resultingingangrene.Gangrenousmastitiscausesapatchyblue
discoloration,andcoldnessofthetissueandleakingofbloodserum
throughtheskin.
 Alsocausessubclinicalmastitisandresultsinaherdmastitisproblem.

15. Tenosynovitis
MALMARUGAN, 2015
Bumblefootinpoultry
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:Infrequentchronic
granulomatouslesionsinvolvingthe
spermaticcordofmalehorses.
Sheep
Tickpyemiainlambs-2-5weekold
lambs(heavilyinfectedwithIxodes
ricinus)
Periorbitaleczemaisaninfection
duetoabrasion
Staphylococcaldermatitisdueto
scratchesfromvegetation
Dogs and Cats:Pyoderma, Otitis externa
and other suppurativeconditions caused
by Sta. intermedius.

19. Diagnosis
Materialsfordiagnosis
Pus,affectedtissueandmilksamples.
Examinationofcultureandpussmear
GramsstainingrevealGram-positiveorganismswithtypical
arrangement.
Isolationandidentificationbyculturemethod:
Organismsgrowwellinordinarylaboratorymedia.
Mostpreferredmedia-mannitolsaltagar.
Bloodagar-primaryisolation-round,smooth,glistening
andmayormaynothavegoldenyellowpigments.
Producedoublezonehaemolysisandhaemolysis.
Haemolysisisbestdemonstratedinbovineredbloodcells.

20. Coagulasetest:Toaloopfulofbacterialcultureinsaline
adropofrabbitplasmaisaddedoveraslide.
Appearanceofclumpswithintenminutesisconsidered
aspositive.
MostoftheStaphylococciproducecoagulaseenzyme,
coagulaseconvertingfibrinogenintofibrinpromoting
bloodclotting.
Diagnosis contd..
Coagulase -Tube test
Coagulase -Slide test

21. Hotistest–slightlyacidrustcolorcolonies
Diagnosis contd..

22. Latexagglutinationtest
Phagetyping
Biochemicaltests:oxidasetest,coagulasetest,
betahaemolysis,pigmentproduction,utilisation
ofmaltoseandmannitolandsensitivityto
novobiocin.
Diagnosis contd..

23. Treatment
Acuteindividualorsporadiccasescouldbetreated
witheffectiveantimicrobial.
Cloxacilliniseffectiveintreatmentof
staphylococcalmastitisindrycowsonaherd
basis.
Otherdrugsthatareeffectiveagainst
staphylococcalinfectionsinanimalsare
chloramphenicol,erythromycin,cephalosporin,
vancomycin,lincomycinandtrimethoprimsulfas.
Methicillinresistanceisindicativeofmultiple
resistance