Vancomycin intermediately resistant Staphylococcus aureus
Vancomycin intermediately resistant Staphylococcus aureus: Excerpt from Handbook of Diseases
Vancomycin intermediately resistant Staphylococcus aureus (VISA) is a mutation of a bacterium that’s spread easily by direct person-to-person contact. It was first discovered in mid-1996 when clinicians found the microbe in a Japanese infant’s surgical wound. Similar isolates were reported in Michigan and New Jersey. Both patients had received multiple courses of vancomycin for methicillin-resistant S. aureus (MRSA) infections.
Another mutation, vancomycin-resistant S. aureus (VRSA) is fully resistant to vancomycin. Patients most at risk for resistant organisms include:
❑ patients with a history of taking vancomycin, third-generation cephalo-sporins, or antibiotics targeted at anaerobic bacteria (such as Clostridium difficile)
❑ patients with indwelling urinary or central venous catheters
❑ elderly patients, especially those with prolonged or repeated hospital admissions
❑ patients with cancer or chronic renal failure
❑ patients undergoing cardiothoracic or intra-abdominal surgery or organ transplants
❑ patients with wounds with an opening to the pelvic or intra-abdominal area, including surgical wounds, burns, and pressure ulcers
❑ patients with enterococcal bacteremia, often associated with endocarditis
❑ patients exposed to contaminated equipment or to a patient with the infecting microbe.
Causes
Vancomycin-resistant enterococcus (VRE) and MRSA enter health care facilities through an infected or colonized patient or a colonized health care worker. It’s thought that VISA and VRSA are colonized in a similar method. They’re spread through direct contact between the patient and caregiver or between patients. They may also be spread through patient contact with contaminated surfaces such as an overbed table. They’re capable of living for weeks on surfaces. They’ve been detected on patient gowns, bed linens, and handrails.
Signs and symptoms
There are no specific signs or symptoms related to this microbe. The causative agent may be found incidentally when culture results show the organism.
Diagnosis
Someone with no signs or symptoms of infection is considered colonized if VISA or VRSA can be isolated from stool or a rectal swab. A patient who is colonized is more than 10 times as likely to become infected with the organism (such as through a breach in the immune system) than a patient who isn’t.
Treatment
There’s virtually no antibiotic to combat VISA or VRSA. Recently, the Centers for Disease Control and Prevention and the Hospital Infection Control Practices Advisory Committee proposed a two-level system of precautions to simplify isolation for resistant organisms. The first level calls for standard precautions, which incorporate features of universal blood and body fluid precautions and body substance isolation precautions to be used for all patient care. The second level calls for transmission-based precautions, implemented when a particular infection is suspected.
To prevent the spread of VISA and VRSA, some hospitals perform weekly surveillance cultures on at-risk patients in intensive care or oncology units and on patients who have been transferred from a long-term care facility. A colonized patient is then placed in contact isolation until he’s culture-negative or discharged. Colonization can last indefinitely; no protocol has been established for the length of time a patient should remain in isolation.
Because no single antibiotic is currently available, the physician may opt not to treat an infection at all. Instead, he may stop all antibiotics and simply wait for normal bacteria to repopulate and replace the strain. Combinations of various drugs may also be used, depending on the infection’s source.
Special considerations
❑ Personnel in contact with an infected patient should wash their hands before and after care of the patient.
CLINICAL TIP: Good hand washing is the most effective way to prevent VISA and VRSA from spreading.
❑ Use an antiseptic soap such as chlor-hexidine; bacteria have been cultured from worker’s hands after they’ve washed with milder soap.
❑ Maintain contact isolation precautions when in contact with the patient. Provide a private room and dedicated equipment, and disinfect the environment.
❑ Change gloves when contaminated or when moving from a “dirty” area of the body to a clean one.
❑ Do not touch potentially contaminated surfaces, such as a bed or bed stand, after removing gown and gloves.
❑ Be particularly prudent in caring for a patient with an ileostomy, colostomy, or draining wound that’s not contained by a dressing.
❑ Instruct family and friends to wear protective garb when they visit the patient, and teach them how to dispose of it.
❑ Provide teaching and emotional support to the patient and family members.
❑ Consider grouping infected patients together (known as cohorting) and having the same nursing staff care for them.
❑ Do not lay equipment used on the patient on the bed or bed stand; wipe it with appropriate disinfectant before leaving the room.
❑ Ensure judicious and careful use of antibiotics. Encourage physicians to limit the use of antibiotics.
❑ Instruct patients to take antibiotics for the full prescription period, even if they begin to feel better.
Book Source Details
- Book Title: Handbook of Diseases
- Author(s): Springhouse
- Year of Publication: 2003
- Copyright Details: Handbook of Diseases, Copyright © 2003 Lippincott Williams & Wilkins.
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Copyright notice for book excerpts: Copyright © 2008 Lippincott Williams & Wilkins. All rights reserved.
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More About This Book:
Title: Handbook of Diseases
Authors: Springhouse
Publisher: Lippincott Williams & Wilkins
Copyright: 2003
ISBN: 1-58255-266-5
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