The Toronto Hospital Policy & Procedure Manual


INFECTION CONTROL
SECTION:  DISEASE SPECIFIC INFORMATION
SUBJECT TITLE:  METHICILLIN-RESISTANT STAPHYLOCOCCUS AUREUS
POLICY #:   60.14
ISSUED BY:  INFECTION CONTROL
DATE:  07.92 (O)
APPROVED BY:  INFECTION CONTROL COMMITTEE
REVIEW DATE:  06.95 (R) , 07.97(R)

GUIDELINES

Staphylococcus aureus is a gram-positive bacteria which forms a part of the normal flora found on skin and mucus membranes. Methicillin-resistant Staphylococcus aureus (MRSA) is a strain of Staphylococcus aureus that is resistant to all penicillinase-resistant penicillins such as methicillin, oxacillin, nafcillin, cloxacillin and dicloxacillin. It is also often resistant to other antibiotics such as clindamycin, erythromycin, tetracycline and aminoglycosides. MRSA is sensitive to vancomycin, and is usually sensitive to: mupirocin(Bactroban), fusidic acid, rifampin and sometimes trimethoprim/sulfamethoxazole.

Colonization refers to the presence of an infectious organism in or on a host, with multiplication and growth. There is no tissue invasion and damage and no signs or symptoms. The major site of colonization of Staphylococcus aureus is the nose. Approximately 30-40% of the general population are nasal carriers. Other common sites are the nasopharynx, axilla, groin and gastrointestinal tract.

Infection occurs when Staphylococcus aureus is associated with tissue invasion with or without clinical manifestations. Common sites of infection in a patient are surgical wounds, invasive devices such as central lines and soft tissue wounds. The patients who are at the highest risk are:

NOTE: At the present time MRSA should be treated in a health care setting whether there is colonization or infection of either patients or staff.

Mode of Transmission
A health care worker who is a nasal carrier of MRSA may disseminate the organism to patients and other staff by droplet spread and/or direct hand contact. Some strains of MRSA are highly transmissible. Given the right conditions(a soiled area), MRSA can live in the environment for up to 30 days so indirect contact (i.e. BP cuffs, stethoscopes, EKG leads, computer keyboards etc.) is a possible mechanism of transmission. However, transmission on the hands of a health care worker is the most common.

Control Measures for Methicillin-Resistant Staphylococcus Aureus

A) Care of Patient in Isolation:

  1. Patients with suspected or confirmed MRSA are immediately placed on STOP isolation using gloves, gowns, masks and a single room. The door does not have to remain closed* (Termination, cohorting of patients or modification of isolation procedures must be done with prior consultation and approval of the Infection Control Practitioner or Hospital Epidemiologist).
  2. Infection Control Practitioner(weekdays) or Infectious Diseases residents(non business hours) are to be notified so that they may record isolation on computer.
  3. Strict handwashing must be observed before and after using gloves. Handwashing and changing of gloves is done between different anatomical sites.
  4. Teaching of the patient and visitors regarding STOP Isolation, MRSA and its treatment should be done. The Infection Control Practitioner may be called to assist with this.
  5. The physician is to be notified immediately so the appropriate treatment may be started.
  6. For neonatal/maternal care, please refer to Perinatal Nursing Manual B - Disease Specific Precautions.

* In areas with high traffic flow it may be preferable to keep the door closed.

B) Cultures:

For suspected or confirmed MRSA from any site the following cultures are done to rule out MRSA carriage at other sites:

  1. Nasal swab requires one swab to culture both nares. Use a gentle circular motion and swab all sides of the nares. Enter in the computer under C & S and mark "Screen for MRSA" in the comment field.
  2. Axillae/groin swab requires one swab to culture both axillae and groin. Swab both axillae before swabbing the groin. Enter in the computer under C & S and type "Screen for MRSA" in the comment field.
  3. Any draining wound requires one swab. Drainage should be gently removed with sterile gauze moistened with normal saline and then with a gentle rolling motion culture the area which shows the most tissue destruction or the area where the most drainage was noted. Enter in the computer under C & S and mark "Screen for MRSA" in the comment field.
  4. Any other cultures as ordered by Infection Control or physician. High risk areas or patients, or the suspicion of an outbreak may require additional cultures.
  5. Surveillance cultures should be done on all roommates and close contacts of a newly diagnosed MRSA positive patient.
  6. Before termination of isolation the patient is to have three negative cultures from each specific site. These are to start no less than 24 hours after the last dose of all antibiotics including topical therapy.

NOTE: The frequency and interval of cultures should be assessed on an individual basis, in consultation with Infection Control Staff and depending on the condition of the patient and the extent of (deep/superficial, localized or systemic) infection. Negative results from three consecutive daily specimens from multiple sites are the minimum requirement to remove isolation. However, three negative cultures taken one week apart may be necessary for patients with deep wound and/or respiratory involvement.

Culturing of staff for MRSA is determined by the Infection Control Practitioner in consultation with the Hospital Epidemiologist. It is done only when cross infection of MRSA by a staff member is suspected.

C) Transfer of Patient with Suspected/Diagnosed MRSA In-Hospital:

  1. Avoid/limit transfers of patient but without compromising care(e.g. tests and x-rays).
  2. When transferring a patient to another floor, MRSA status and significant cultures must be reported prior to the transfer. The Infection Control Practitioner should be notified of all floor transfers.
  3. Prior to transferring a patient to a test notify the staff in that area of the MRSA status of the patient.
  4. When transferring a patient to the O.R., his/her MRSA status must be reported prior to the transfer to both O.R. and the PACU. At the General, these patients will be recovered post-operatively in the Surgical Intensive Care Unit in a single room by a PACU staff so early notification is essential. At the Western, patients will be recovered in a separate bay.
  5. When a patient with suspected/diagnosed MRSA nasal carriage is transferred or is out of his/her room, the patient must wear a mask. Any body site with suspected/diagnosed MRSA must be covered. This is also done if the patient requires to be ambulated.

D) Transfer of Patient with Suspected/Diagnosed MRSA to Another Facility:

  1. The Infection Control Practitioner must be notified prior to the patient transfer. This is to ensure contact is made with the receiving facility's Infection Control department.
  2. All relevant information, such as history and dates of cultures should be sent with the patient upon transfer.
E) Receiving a Patient with Suspected/Diagnosed MRSA from Another Facility:

  1. The Infection Control Practitioner must be notified as soon as possible when transfer of a patient will occur or has already occurred.
  2. All control measures as outlined in Section A are to be implemented on arrival.
  3. Re-culture as in Section B.

F) Discharge of Patient with Suspected/Diagnosed MRSA to Home:

  1. The Infection Control Practitioner should be notified prior to discharge to consult with family, Homecare officials or to notify Infection Control staff at the receiving institution.
  2. I f applicable Homecare must be notified prior to discharge.
  3. The family physician should be notified that the patient has been treated for MRSA.
  4. Patient should be told to report his MRSA status to any medical office or receiving institution(including TTH).

Treatment of Methicillin-Resistant Staphylococcus Aureus

A) Patients (If in doubt the Infectious Diseases Service may be consulted)

1. Nasal Carriers:

  1. Small amount of mupirocin ointment(2%) or other suitable anti-staphylococcal agent to both nares TID for 7 days. Remove previous dose before re-applying.
  2. Twenty-four hours after the mupirocin has been discontinued reculture the patients nares as noted previously, obtaining 3 consecutive swabs at intervals determined on an individual assessment of the patient. A longer course may be ordered if seven days is not sufficient.

2. Other body sites and/or body substances:

  1. Mupirocin ointment or other agent may be ordered for soft tissue wounds or other sites(e.g. vagina).
  2. Antibiotics may be given systematically per sensitivity results for a course of 7-14 days.
  3. Patient should be bathed with hair shampooed for seven consecutive days in an attempt to eliminate or decrease skin load of MRSA. Full-strength Chlorhexidene 2% or other alternative followed by a thorough tap water rinse is used. Skin must be intact. This should coincide with the timing of receipt of antibiotic If irritation or skin breakdown occurs discontinue use of Chlorhexidene 2%.

3. Patients with Impaired Renal Function:

  1. Start times for reculturing of renal patients(without renal failure) who have received Vancomycin treatment will be determined by the Infection Control Practitioner in consultation with the Pharmacist.
  2. Continuous Ambulatory Peritoneal Dialysis patients with End-Stage Renal Failure who have received 0.5-1.0 Grams of Vancomycin intra-peritoneally may be recultured one week after the last dose has been given
  3. Haemodialysis patients will be assessed individually

4. Patients with Impaired Hepatic Function:
  1. Reculturing of patients with cirrhosis of the liver or active viral hepatitis who have received 300-600 mg of Rifampin should be started at least three days after the last dose has been given.

NOTE: If first course of treatment fails, a repeat course of the treatments maybe necessary. Expert consultation may be required if > 2 treatment courses fail to eliminate carriage.

B) Employees

  1. The Infection Control Pratitioner or designate will notify staff of MRSA carriage. The employee should report immediately to Occupational Health for assessment.
  2. Apply mupirocin ointment or other appropriate agents intranasally TID for 7 days or as ordered by the Occupational Health physician. Remove previous dose before re-applying.
  3. Twenty-four hours after the mupirocin has been discontinued reculture both nares (one swab) on three consecutive days.
  4. When three negative cultures have been confirmed by Occupational Health, the employee may return to work or if working discontinue precautions.
  5. Three months after the incident reculture both nares (one swab) to ensure re-colonization has not occurred.
  6. Employees should shower/bath(body and hair) with Chlorhexidene 2% or other appropriate soap daily for the seven days of antibiotic use. Staff who are colonized may be allowed to continue to work providing they follow Infection Control guidelines and precautions.

C) Colonized Staff Precautions for Patients

Staff who are colonized may be allowed to continue to work providing they follow Infection Control guidelines and precautions.


  1. The employee will report to Occupational Health daily where cultures will be done daily while on medication. This is to assess bacterial load of the staff member. If load remains high the staff member may be removed from duty.
  2. If possible staff will be assigned duties that do not required close patient contact.
  3. Staff will wear mask, gown and gloves for all direct patient care and close contact. Specific information will be given by Infection Control staff in a private educational session.
Equipment

  1. Re-usable equipment that is to be sterilized may be placed in the blue box in the utility room The lid of the blue box is to remain closed
  2. All patients should have dedicated stethoscopes, blood pressure cuffs and glass thermometers. Re-usable equipment that cannot be sterilized is to be cleansed with a hospital-approved disinfectant. The disinfectant should be kept on the cart.
  3. Meal dishes are to be removed from tray and taken into room. Replace dishes back on tray and cover for usual pick-up. Disposable dishes are not necessary.
  4. Lab Specimens are covered under BSP.
  5. Linen is placed in the regular clear plastic bag kept in the room. It is changed when 3/4 full.
  6. Garbage is placed in the yellow garbage bag kept in the room. It is changed when 3/4 full. As much paper and garbage as possible should be discarded prior to entering the room.
  7. Sharps are disposed of in the usual manner. Blood and body secretions on the container must be wiped off with a hospital-approved disinfectant prior to removal from the room.

NOTE: Isolation carts are obtained from Transportation.

REFERENCES:

  1. Bennett, May Ellen. "Recommendations from a Minnesota task force for the management of persons with MRSA." AM. J. Infec Control 1992; 20: 42-48.
  2. Wenzel, Richard P. "Methicillin-Resistant Staphylococcus Aureus: Implications for the 1990's and Effective Control Measures." Am J. Infec Control 1991; 91(Supplement 38): 221-227.
  3. Association for Professionals in Infection Control and Epidemiology, Inc. "APCI Infection Control and Applied Epidemiology - Principles and Practice." Mosby: 1996; 78-1-78-7.

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