This document discusses Staphylococcus, including its morphology, cultural characteristics, pathogenicity, laboratory diagnosis, and treatment. Staphylococcus is a gram-positive, round bacterium that grows in clusters and produces golden yellow colonies on nutrient agar. It can cause both superficial and deep infections in humans and produces toxins that lead to conditions like toxic shock syndrome and scalded skin syndrome. Laboratory diagnosis involves examining samples under a microscope, culturing them on selective media, and identifying colonies using tests like coagulase. Effective antibiotic treatments include penicillin, methicillin, and vancomycin.

1. STAPHYLOCOCCUS
RATHEESH R L

2. • Medically important species is staphylococcus
aureus

4. MORPHOLOGY
• They are gram positive, ovoid, arranged in
bunches, non- motile, non- sporing and
anaerobic type.
• They measure 0.8 to 0.9 micrometer in
diameter.

6. CULTURAL CHARACTERISTICS
Staphylococcus grows usually in simple or
ordinary culture media under aerobic or
anaerobic conditions at optimum temperature
of 37 C and pH 7.5

7. NUTRIENT AGAR MEDIUM
• After over night incubation, it mostly produces
pigmented, golden yellow, round, smooth,
raised colonies with 2-4mm diameter

8. BLOOD AGAR MEDIUM
• The organism produces beta hemolysis in this
medium containing. rabbit Or sheep blood.

9. LIQUID MEDIUM
• In nutrient broth the organism produces
uniform turbidity

10. MacConkey's agar medium
• The organism produces pink colonies which
are of pinhead size indicating that they are
lactose fermenting

11. PATHOGENECITY
• The pathogenecity of organism is mainly due
to coagulase produced which inhibiting
phagocytosis

12. Cutaneous infection
• The organism causes superficial infections
like,pestules, abscesses, carbuncles, styes,
impetigo, furunctes (boils)

13. Deep infection
These include acute osteomyelitis, tonsilitis,
pharyngitis, pneumonitis,meningitis

14. Skin exfoliation/exfoliative disease
• The toxin (epidermolytic toxin or TSST-l)
produced by the organism causes striping of
superficial layers of skin that causes a clinical
condition known as Ritter's disease or scalded
skin syndrome (SSS) characterized by painful
rashes.

15. Toxic food poisoning
• When preformed toxins of the organism
growing In contaminated food (especially fish,
meat, milk & milk products) are ingested, the
toxins act on mucosal surface of GI tract
causing Staphylococcal food poisoning within
2-5 hours of ingestion characterized by
nausea, vomiting and diarrhea.

16. Toxic Shock Syndrome
• It is usually caused by the enterotoxin
(enterotoxin F) produced by organism in gut
characterized by fever, hypotension, vomiting,
confusion, headache, diarrhea, & rashes.

17. LABORATORY DIAGNOSIS
• Haematological investigations
Total leucocyte count (TLC):
Shows leucocytosis (count > 10.000
cells/cubic mm)
Differential leucocyte count (DLC) :
Shows increase in neutrophil count (more
than 80%

18. Bacteriological investigation
• Specimen: Depending upon the nature of
lesions specimen Is collected like pus from
suppurative lesion, CSF from meningitis, blood
from septicemia, midstream urine from UTI,
sputum from respiratory infection &
suspected food, feces or vomits from food
poisoning cases.

19. 1. Microscopy:
Smear is made from the above
specimen on a clean slide & subjected to Gram
staining. Examination of Gram stained smear
shows Gram-positive cocci in clusters.

20. 2. Culture:
• The above specimen is inoculated on
Nutrient agar medium, Blood Agar medium or
Mannitol agar medium (selective media) & the
plates are incubated at 37 C for 24 hours
• On nutrient agar colonies will appear as
golden yellow or white which are confirmed
by coagulase test

21. • On blood agar plates the organism shows beta
hemolysis and on mannitol agar colonies will
be pink due to fermentation of lactose by the
organism.

22. TREATMENT
• Benzyl penicillin, methicillin and cloxacillin are
effective.
• At present vancomycin is most effect drug
against staphylococci.