Staphylococcus aureus (Anaerobic Gram +ve Coccus)
Staphylococcus aureus is the non-motile, non-spore forming bacterium that is a member of the Firmicutes, and is frequently found in the human respiratory tract and on the skin.
S. aureus is responsible for many infections but it may also occur as a commensal. The presence of S. aureus does not always indicate infection. S. aureus can survive from hours to weeks, or even months, on dry environmental surfaces, depending on strain.
Staphylococcus aureus causes;
- Pyogenic infection (endocarditis, septic arthritis & osteomyelitis)
- Food poisoning
- Scalded skin syndrome
- Toxic shock syndrome
- Hospital acquired pneumonia
- Surgical wound infection
- Bacterial conjuctivitis
- Skin infections (folliculitis, cellulitis, impetigo)
Staphylococcus aureus produces is the most important than other species of genus. It produces several important enzymes or chemical substances such as;
Catalase is important enzyme responsible for the virulency of the bacteria. It degrades the H2O2 released from neutrophils which is microbicidal (kill the bacteria). So catalase limits the ability of the neutrophils to kill.