Staphylococcus aureus

By: Lauren Oswald APBio

Genus: Staphylococcus Species: aureus Domain: Bacteria Kingdom: Eubacteria Phylum: Firmicutes Class: Bacilli Order: Bacillales Family: Staphylococcaceae

Classification

Shape and ArrangementShape: coccus

Arrangement: staphylo

Coccus: Staphylo: spherical grape-like clusters

Forms in clusters because it reproduces asexually. ◦ It reproduces its DNA in which the membrane

stretches out and separates the DNA molecule. The cells form a hallow space that will divide into new cells. The new cell wall does not fully separate from the existing cell wall, forming clusters.

Unique Structural Features

Habitat Soil skin mucous

S. epidermis may represent up to 90% of the normal microbiota of the skin

Mode of Nutrition ◦ It converts high energy

molecules like glucose into energy through cellular respiration.

Effect of Oxygen◦ Staphylococcus aureus is a

facultative anaerobe. It will normally perform aerobic cellular respiration, but if oxygen is unavailable it can perform anaerobic respiration for energy production.

Catalase◦ Produces an enzyme called

catalase. Catalase helps Staphylococcus aureus break down hydrogen peroxide in oxygen a water. Hydrogen peroxide can be a toxin for some organisms.

Features

• Gram-positive, cluster-forming coccus •nonmotile

•Nonspore forming facultative anaerobe•Fermentation of glucose produces mainly lactic acid ferments mannitol

(distinguishes from S. epidermidis) •catalase positive

•coagulase positive •golden yellow colony on agar

Click icon to add picture

Characteristics

Gram stain of Staphylococcus aureus in pustular exudate.

The bacteria is becoming more resistant to treatment. ◦ In past decades antibiotic

resistance was not a major problem, however now it will continue to get worst for future generations health and economy.

◦ Resistance will promote research for future applications to treat infections without causing further antibiotic resistance as well and decrease the medications or dosage one takes.

Historical Significance

Health Related Issues

Two types

Healthcare-associated MRSA (HA-MRSA) infections occur in people who are or have recently been in a hospital. MRSA bacteria are responsible for a large percentage of hospital-acquired staph infections. Surgery patients or people who have been hospitalized in the past year are at a higher risk.

Community-associated MRSA (CA-MRSA) infections occur in healthy people. The infections have occurred in such people as athletes who share equipment or personal items and children in daycare facilities.

The most popular being MRSA (Methicillin-resistant Staphylococcus aureus) a bacterial infection that is highly resistant to some antibiotics.

Causes The Bacteria enters

the body through a cut, sore, catheter, or breathing tube.

Tests Blood, drainage

fluid, skin, sputum, or urine cultures.

Symptoms Red, swollen, and painful area on

the skin. Drainage of puss or fluid from the

site. Skin abscess Warmth around the infected area.

◦ More serious staph infections

Chest pain Chills Cough Fatigue Fever Headache and muscle aches Malaise Rash Shortness of breath

MRSA

Images of MRSA

Treatment ◦ Simple infections

Draining the skin sore local skin MRSA infection. ◦ More serious infections are becoming increasingly difficult to treat.

Kidney dialysis Oxygen Antibiotics that may still work include:

Clindamycin Daptomycin Doxycycline Linezolid Minocycline Tetracycline Trimethoprim Vancomycin

Prevention ◦ Wash your hands frequently,

especially if visiting someone in a hospital or long-term care facility.

◦ Do not share personal items such as towels or razors with another person.

◦ Cover all wounds with a clean bandage, and avoid contact with other people’s soiled bandages.

◦ Clean shared sporting equipment with antiseptic solution before using it.

◦ Avoid common whirlpools or saunas if another participant has an open sore.

Further exploration facts…S. AUREUS IS AN URGENT PUBLIC

HEALTH ISSUE

S. aureus infections have increased in the past 20 years due to the increased use of invasive devices in both hospital and home care settings and the rise in the number of elderly and immune compromised patients.

The increase in anti-biotic-resistant strains of the bacteria have increased, which limits therapies to treat and prevent infections. ◦ S. aureus is one of the most nosocomial infections. ◦ Complications related to S. aureus infections have high rates of

mortality. ◦ High healthcare costs.

“The total cost of antimicrobial resistance to the U.S. health care system was nearly $5 billion in 1998, according to IOM.  Experts believe the true costs in 2009 numbers may be ten times that amount today.  Treating resistant pathogens often requires more expensive drugs and extended hospital stays.”-idsociety

◦ S. aureus is the most common cause of community-acquired bacterium.

 "PubMed Health - MRSA." Web. 02 Feb. 2011. http://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0004520

 "Staphylococcus Aureus and S. Epidermis." Welcome to the Schenectady County Community College Web Site. Web. 02 Feb. 2011. <http://www.sunysccc.edu/academic/mst/microbes/13saure.htm>.

 "Staphylococcus Aureus." Online Textbook of Bacteriology. Web. 02 Feb. 2011. <http://www.textbookofbacteriology.net/staph.html>.

 "Staphylococcus Aureus." Wikipedia, the Free Encyclopedia. Web. 02 Feb. 2011. <http://en.wikipedia.org/wiki/Staphylococcus_aureus>.

"Antibiotic Resistance." Science Daily: News & Articles in Science, Health, Environment & Technology. Web. 02 Feb. 2011. <http://www.sciencedaily.com/articles/a/antibiotic_resistance.htm>.

Work Cited