STAPHYLOCOCCUS AUREUS (S. AUREUS)

Introduction

• Staphylococcus Aureus is a gram positive bacteria that produce yellow pigment, facultative anaerobe, does not produce spores and not motile.
• Generally it grows in pairs or groups in the human skin, nose, mouth and colon, in which the immune system is in normal state.
• Optimum growth of S. Aureus is at 37 °C and it is a normal microflora in humans.

Picture 1: Gram positive S. Aureus	Picture 2:S. Aureus cultured on blood agar

                                          Source: www.healthhype.com/lab-tests-for-staph.html

Mode of Transmission

S. Aureus is usually carried on the skin or in the nose of healthy people. Mostly, people carry the bacteria in their nose. S. Aureus can spread through skin-to-skin contact or by touching contaminated surfaces. Lack of personal hygiene and wound that was not covered correctly can cause infection of S. Aureus.

Picture 3: Area that is usually infected with bacteria Staphylococcus Aureus

Source: textbookofbacteriology.net/staph_2.html

Infection to Humans

• Common infections caused by S. Aureus, include boils, pimples and abscesses (infection of skin), impetigo; a highly contagious, crusty skin infection that can affect newborns and children.
• Most of the infection caused by these bacteria will produce pus. Therefore, it is called pyogenic bacteria. These bacteria also can cause food poisoning.
• More serious infections include meningitis which is the infection of the membranes that line the brain, osteomyelitis (infection of the bone and bone marrow), pneumonia (infection of one or both lungs), septic phlebitis (vein infection) and endocarditis (infection of heart valves).

(a) Mouth and nose infection	(b) Shoulder infection

Picture 4 (a), (b): Example of Infections

Source: www.healthhype.com/staph-skin-infections.html

Treatment of Infection

• Minor skin infection can be treated with an antibiotic ointment such as mupirocin (Bactroban) nasal gel and daily skin sanitizer. In some cases, oral antibiotics may be given for skin infections.
• Skin abscesses requiring more consistent care and serious abscess may require surgical drainage.
• Severe infection of S. Aureus requires treatment with intravenous antibiotics. The choice of antibiotic depends on the susceptibility results from the laboratory. This includes penicillin such as nafcillin and oxacillin or cephalosporins, 1^st or 2^nd generation (e.g., cephalexin, cefuroxime) and clindamycin.

Prevention

• A more conservative approach to the use of antibiotics.
• Maintain or improve hygiene practices in house and public places.
• Awareness to the community about the S. Aureus.
• Personal hygiene practices should be implemented by all hospital staff.
• Open wounds should be cleaned and covered.
• If there are any related symptoms, please refer to the clinics or hospitals immediately.

References

1. Abbott S.L. (2003). Klebsiella, Enterobacter, Citrobacter, Serratia, Plesiomonas and other Enterobacteriaceae. In Manual of Clinical Microbiology, 8th edn, pp. 684–696. Edited by P. R. Murray, et al Washington, DC: American Society for Microbiology.
2. Honeyman A.L., Friedman H., Bendinelli M. ( 2001). Staphylococcus aureus Infection and Disease. New York: Plenum Publishers.
3. textbookofbacteriology.net/staph_2.html
4. www.healthhype.com/lab-tests-for-staph.html
5. www.medicinenet.com/staph_infection/article.htm