Staphylococcus Aureus

Characteristics

Morphology Gram-positive cocci, usually occurs in clusters, nonspore forming, non-motile, coagulase positive, facultative anaerobes.
Growth Conditions

Tryptic Soy Broth

Health Hazards

Host Range

Humans, wild and domestic animals

Modes of Transmission

Ingestion of food containing enterotoxins, contact with nasal carriers, contact with draining lesions or purulent discharges, also spread by person-to-person contact; Indirectly by contact with fomites; Indirectly or directly by contact with infected animals

Signs and Symptoms

Accidental ingestion: violent onset of severe nausea, cramps, vomiting, and diarrhea if preformed enterotoxin is present Surface infections: impetigo, folliculitis, abscesses, boils, infected lacerations Systemic infections: onset of fever, headache, myalgia, can progress to endocarditis, meningitis, septic arthritis, pneumonia, osteomyelitis, sepsis

Infectious Dose Virulence varies for different strains 
Incubation Period 30 minutes-8 hours when consuming contaminated food with enterotoxin. Otherwise, typically 4 – 10 days; disease may not occur until several months after colonization of mucosal surfaces.

Medical Precautions/Treatment

Prophylaxis Hand-hygiene; Elimination of nasal carriage by using topical mupirocin. Mupirocin also eliminates transient hand carriage by eliminating the mucosal reservoir
Vaccines None

Treatment

Incision and drainage for localized skin infections; antibiotic therapy for severe infections; Many strains resistant to antibiotics; Sensitivity must be determined for each strain

Surveillance

Monitor for signs of food poisoning when ingestion occurs. Monitor for skin inflammation; isolation of organism from wound, blood, CSF, or urine.

Emory Requirements Report all exposures

Laboratory Hazards

Laboratory Acquired Infections (LAIs) 29 reported cases up to 1973 with 1 death. Most common cause of laboratory infection was accidental self-exposure via the mucous membranes by touching contaminated hands to face or eyes.
Sources Contaminated food, blood, abscesses, lesion exudates, CSF, respiratory specimen, feces, and urine

Supplemental References

Containment

BSL-2 For all activities involving known or potentially infected cultures
BSL-3 Activities with high potential for aerosol or droplet production and activities using large quantities of S. aureus
ABSL-2 For all procedures utilizing infected animals
ABSL-3 For all procedures with high potential for aerosol or droplet production 

Spill Procedures

Small Notify others working in the lab. Allow aerosols to settle. Don appropriate PPE. Cover area of the spill with paper towels and apply an EPA registered disinfectant, working from the perimeter towards the center. Allow 30 minutes of contact time before disposal and cleanup of spill materials.
Large

Contact Emory’s Biosafety Officer (404-727-8863),
the EHSO Office (404-727-5922), or
The Spill Response Team (404-727-2888).

Exposure Procedures

Mucous membrane Flush eyes, mouth or nose for 15 minutes at eyewash station.
Other Exposures Wash area with soap and water for 15 minutes.
Reporting Immediately report incident to supervisor, complete an employee incident report in PeopleSoft.
Medical Followup 

7am-4pm (OIM): EUH (404-686-7941) EUHM (404-686-7106) WW (404-728-6431)

After Hours: OIM NP On Call 404-686-5500 PIC# 50464

Needle Stick (OIM): EUH (404-686-8587) EUHM (404-686-2352)

Yerkes: Maureen Thompson Office (404-727-8012) Cell (404-275-0963)

Viability

Disinfection

70% ethanol, chlorohexadine, 1% sodium hypochlorite, 2% glutaraldehyde, formaldehyde, .25% benzalkonium chloride

Inactivation

Sensitive to dry heat. Dry Heat (160-170°C for at least 1 hour).

Survival Outside Host Carcass and organs – 42 days; Skin – 30 minutes to 38 days; meat products – 60 days; floor – less than 7 days; glassware – 46 hours; sunlight – 17 hours; UV light – 7 hours

Personal Protective Equipment (PPE)

Minimum PPE Requirements At minimum, personnel are required to don gloves, closed toed shoes, lab coat, and appropriate face and eye protection prior to working with S. aureus. Additional PPE may be required depending on lab specific SOPs.
Additional Precautions Avoid injuries from contaminated sharp instruments. Avoid bites and scratches from infected animals. Avoid direct contact with open skin or lesions of skin. 

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