Staphylococcus aureus
Morphology | Gram-positive cocci, usually occurs in clusters, nonspore forming, non-motile, coagulase positive, facultative anaerobes. |
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Disease |
Toxic shock syndrome, food poisoning, intoxication, impetigo. |
Zoonosis |
Yes, indirect and direct contact with infected animals, especially cows. |
Host Range | Humans and Animals. |
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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, follicutis, 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 to 8 hours when consuming contaminated food with enterotoxin. Otherwise, typically 4 to 10 days. Disease may not occur until several months after colonization of mucosal surfaces. |
Prophylaxis | Hand-hygiene; Elimination of nasal carriage by using topical mupirocin. Mupirocin also eliminates transient hand carriage by eliminating the mucosal reservoir. |
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Vaccines | None available |
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. |
MSU Requirements | Report any exposures |
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. |
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Sources | Contaminated food, blood, abscesses, lesion exudates, CFS, respiratory specimen, feces, and urine. Cultures, frozen stocks, other samples described in IBC protocol. |
Risk Group 2
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Agents that are associated with human disease which is rarely serious and for which preventive or therapeutic interventions are often available. |
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BSL2
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For all procedures involving suspected or known infectious specimen or cultures.
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ABSL2
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For all procedures utilizing infected animals.
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Small
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Notify others working in the lab. Remove PPE and don new PPE. Cover area of the spill
with absorbent material and add fresh 1:10 bleach:water. Allow 20 munutes (or as directed)
of contact time. After 20 minutes, cleanup and dispose of materials.
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Large
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Mucous membrane
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Flush eyes, mouth, or nose for 5 minutes at eyewash station.
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Other Exposures
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Wash area with soap and water for 5 minutes.
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Reporting |
Immediately report incident to supervisor, complete a First Report of Injury form, and submit to Safety and Risk Management.
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Medical Follow-up
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During business hours: Bridger Occupational Health 3406 Laramie Drive. Weekdays 8am -6pm. Weekends 9am-5pm
After business hours: Bozeman Deaconess Hospital Emergency Room 915 Highland Blvd Bozeman, MT |
Disinfection | Susceptible to 1:10 bleach:water, 70 % ethanol and 2 % gluteraldehyde, chlorohexadine, formaldehyde, and 0.25 % benzalkonium chloride. |
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Inactivation | Inactivated by moist heat (15 minutes at 121°C) and dry heat (1 hour at 160-170° C). |
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 days; UV light – 7 hours. |
Minimum PPE Requirements
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Lab coat, disposable gloves, safety glasses, closed toed shoes, long pants
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Additional Precautions
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Additioanl PPE may be required depending on lab specific SOPs and IBC Protocol. |