Gram positive bacteria

Gram positive bacteria

1. GRAM POSITIVE BACTERIA PRESENTED BY SARA HUSSAM M.PHILL MICROBIOLOGY 2 ND SEMISTER

2. BACTERIA Bacteria  are single-cell organisms that are neither plants nor animals. They usually measure a few micrometers in length and exist together in communities of millions.

3. Bacteria are thought to have been the  first organisms  to appear on earth, about 4 billion years ago. The oldest known fossils are of bacteria-like organisms . Some bacteria are harmful while others are beneficial and can serve for medicinal purpose.

4. CLASSIFICATION OF BACTERIA There are many bases of classification of bacteria like Classification on the bases of shape. Classification on the bases of cell wall composition and their staining.

5. ON THE BASIS OF STAINING OF BACTERIAL CELL WALL Discovered by H.C. Gram in 1884. It allows a large proportion of clinically important bacteria to be classified as either Gram positive or negative based on their morphology and differential staining properties.

6. GRAM POSITIVE AND GRAM NEGATIVE BACTERIA GRAM POSITIVE BACTERIA Retains crystal violet dye after staining GRAM NEGATIVE BACTERIA Do not retain crystal violet dye after staining

7. GRAM POSITIVE BACTERIA : The Gram positive bacteria have a cell wall composed of a thick layer of a particular substance (called peptidologlycan ).

8. Gram positive bacteria includes 1) cocci ( round shaped) 2) bacilli (rod shaped)

9. Some of the common diseases causing Gram positive bacteria are: staphylococcus aureus , streptococcues pneumoniae , bacillus anthrax, clostiridium tetani , corynebacterium diphtheria, enterococci

10. STAPHYLOCOCCUS AUREUS:   S. aureus can cause inflammatory diseases including skin infections, pneumonia, endocarditis , septic arthritis, osteomyelitis , and abscesses

11. STREPTOCOCCUS PNEUMONIAE: Streptococcus pneumoniae  is a gram-positive, encapsulated, lancet-shaped diplococci most commonly causing otitis media, pneumonia, sinusitis, and meningitis

12. BACILLUS ANTHRACIS: Bacillus anthracis is a gram-positive spore-forming rod that produces anthrax toxin resulting in an ulcer with a black eschar .

13. CLOSTRIDIUM TETANI: Clostridium tetani is a gram-positive spore-forming rod that causes tetanus, which is a medical emergency and cause severe tightening of muscles all over the body and can cause locking of the jaw making the mouth impossible to open

14. CORYNEBACTERIUM DIPTHARIA Corynebacterium diphtheria is a gram-positive club-shaped rod which can cause pseudomembranous pharyngitis , myocarditis and neural tissue damage.

15. ENTERO COCCI: Entero cocci is a gram positive   bacteria that cause biliary tract infections and UTIs

16. SIGNS AND SYMPTOMS Draining sinus tracts Erythema Fever Superficial abscesses Warmth

17. LABORATRY TESTS Once a gram-positive organism infection is suspected, these laboratory studies are useful : CBC Blood cultures Coagulase test Joint aspiration if a septic joint is suspected

18. TREATMENT Most infections due to  Gram - positive  organisms can be  treated  with quite a small number of  antibiotics . Penicillin, cloxacillin , and erythromycin should be enough to cover 90 per cent of  Gram - positive  infections .