Bring your staff up to date on fighting infections
Bring your staff up to date on fighting infections
A field guide to VRE and MRSA
By Michelle F. Boasten, RN
FBE Service Network
Akron, OH
It would seem that something so tiny and undetectable to the naked human eye could never win a fight against a human being. This army is powerful. Without guns, airplanes, or stealth bombers, they deliver a deadly blow to hundreds of thousands of human beings every day. The fight is between microorganisms and human beings.
Antibiotic-resistant organisms are dangerous
Since the discovery of penicillin, antibiotics have long been regarded as miracle drugs with the ability to eradicate infection. But what the scientists didn’t know is that antibiotics have the ability of inadvertently promoting the development of organisms that can kill.
Microbes try to survive just like any other living creature and because of the indiscriminate and prolific use of antibiotics for both prophylaxis and treatment, overuse of antibiotics has given bacteria the chance to develop defenses against their use. This new capability allows resistant strains of microorganisms to flourish when antibiotics control their more sensitive strains.
Preventing overuse of antibiotics lies largely in the hands of physicians. As nurses, it is important to recognize exactly why antibiotics are prescribed. Two of the most prevalent antibiotic- resistant microbes are vancomycin-resistant enterococcus (VRE) and methicillin-resistant Staphylococcus aureus (MRSA). Hospitals in more than 40 states have reported VRE, with rates as high as 14% in oncology units of large teaching hospitals.
Once limited to large teaching hospitals and tertiary care centers, MRSA is now endemic in nursing homes, long-term care facilities, and even community hospitals. Both enterococci and staphylococcus are part of the body’s normal flora. Normal flora are the bacteria that we acquire after birth that help ensure survival.
Normal flora are essential for good health and generally not harmful when the immune system is functioning properly. Enterococci, for example, are primarily found in the intestine, where they join other bacteria to protect the body from potentially harmful microbes.
As long as bacteria stay in their assigned places, everything is fine. But if the body’s natural defense system breaks down during invasive procedures, surgery, trauma, or chemotherapy, these normally benign bacteria can invade tissue, proliferate, and cause infection.
Enterococcal infections were once easily treated with high doses of penicillin or ampicillin. After enterococcus started to develop resistance to those drugs, clinicians treated infections with aminoglycosides such as gentamicin. When enterococcus also became resistant to aminoglycosides, clinicians started treating them with vancomycin. It is highly suspected that an over-reliance on antibiotics has led to the development of VRE; it is not easily treated with any known antibiotic available today.
Once hailed as a miracle drug’
Penicillin was considered the miracle drug for staphylococcal infections. In 1941, virtually every strain of S. aureus was susceptible to penicillin. Today, up to 90% of staphylococcal isolates or strains are penicillin-resistant, and about 27% of all S. aureus isolates are resistant to methicillin, a penicillin derivative. These strains may also resist cephalosporins, aminoglycosides, erythromycin, tetracycline, and clindamycin. As you can see, when the microbes become resistant, it places us right back where we started prior to the discovery of antibiotics.
Several groups carry a moderate risk of infection, but infants, the elderly, and immunocompromised populations are most vulnerable to infection. Additionally, those with severe underlying disease and those with a history of taking vancomycin, third-generation cephalosporins, or antibiotics targeted at anaerobic bacteria, such as Clostridium difficile, are also at high risk for infection.
Other populations that should be regarded at moderate to high risk include patients or staff in these situations:
• indwelling urinary or central venous catheters;
• prolonged or repeated hospital admissions;
• malignancies or chronic renal failure;
• cardiothoracic or intra-abdominal surgery;
• organ transplants;
• wounds with an opening to the pelvic or intra-abdominal area, including surgical wounds, burns, and pressure ulcers;
• endocarditis;
• exposure to contaminated equipment;
• exposure to a VRE-positive patient.
Spreading and stopping VRE and MRSA
Like the normal chain of infection, VRE enters through an infected or colonized patient or colonized health care worker known as the host. Someone with no signs or symptoms of infection is considered colonized if VRE can be isolated from stool or a rectal swab. If a patient is colonized, they are 10 times more likely to become infected with VRE if there’s a breach in the immune system.
VRE is spread through direct contact between the patient and caregiver or patient to patient. It can also be spread through patient contact with contaminated surfaces such as an over-the-bed table. Capable of living for weeks on surfaces, VRE has been detected on patient gowns, bed linens, and handrails.
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. 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. As a prevention measure, some hospitals perform weekly surveillance cultures on at-risk patients in intensive care units or oncology units and those who’ve been transferred from a long-term care facility. Any colonized patient is then placed in contact isolation until he or she is culture-negative or discharged. Colonization can last indefinitely, and no protocol has been established for the length of time a patient should remain in isolation.
Because no single antibiotic currently available can eradicate VRE, natural healing methods are used. In these cases, all antibiotics will be stopped and the treatment is to wait for normal bacteria to repopulate and replace the VRE strain. Another option is to try one of several drug combinations, depending on the source of the infection.
Patients most at risk for MRSA include those who are immunosuppressed, burn victims, intubated patients, and those with central venous catheters, surgical wounds, or dermatitis. Others at risk include those with prosthetic devices, heart valves, and postoperative wound infections.
Other risk factors include prolonged hospital stays, extended therapy with multiple or broad-spectrum antibiotics, and close proximity to those colonized or infected with MRSA. Also at risk are patients with acute endocarditis, bacteremia, cervicitis, meningitis, pericarditis, and pneumonia.
As with VRE, MRSA enters through a host, such as an infected or colonized patient or colonized health care worker. Although MRSA has been recovered from environmental surfaces, it’s transmitted mainly on the hands of health care workers.
Many colonized individuals become silent carriers. The most frequent site of colonization is the anterior nares — 40% of adults and most children become transient nasal carriers. Other sites include the groin, axilla, and gut, though these sites aren’t as common. Typically, MRSA colonization is diagnosed by isolating bacteria from nasal secretions.
To eradicate MRSA colonization in the nares, topical mupirocin is applied inside the nostrils. Other protocols involve combining a topical agent and an oral antibiotic. Most institutions keep patients in isolation until surveillance cultures are negative.
To attack MRSA infection, vancomycin is the drug of choice. But it can have serious adverse effects, mostly caused by histamine release; reactions range from itching to anaphylaxis. Some clinicians also add rifampin, but whether rifampin acts synergistically or antagonistically when given with vancomycin is controversial.
It takes teamwork to prevent the spread
Preventing the spread of dangerous infections is a team effort. With help from physicians, infection control, lab personnel, and other staff, you can go a long way toward stopping these malicious microbes. Whether you care for a patient with MRSA or VRE, you’re responsible for containing the infection.
Along with your facility’s protocol, follow these guidelines:
• Wash your hands before and after caring for any patient. Good hand washing is the most effective way to prevent VRE and MRSA from spreading. Wash your hands even if you wear gloves — enterococci have been recovered from hands that had been gloved.
• Use an antiseptic soap such as chlorhexidine. Enterococci have been cultured from health care workers’ hands after they’ve washed with a milder soap. One study showed that without proper hand washing, MRSA could survive on health care workers’ hands for up to three hours.
• Institute contact isolation precautions. This includes wearing gloves and a gown if you might be in direct patient contact, giving the patient a private room, using dedicated equipment, and disinfecting the environment.
• Use standard precautions, being sure to wear a face shield and mask to prevent infection spreading from splashes. After you remove your gown and gloves, don’t touch any potentially contaminated surface, such as a bed or bed stand. This is especially important for VRE.
If your patient is incontinent or has diarrhea, change gloves when moving from a dirty area of the body to a clean one, especially with VRE patients. Be particularly prudent in caring for a patient with an ileostomy, colostomy, or draining wound not contained by a dressing. Again, this is especially important with VRE patients.
• Teach staff and patients’ families about infection control and universal precautions. Make sure family and friends know why they need to wear protective garb when they visit the patient, how to put it on, and how to dispose of it. Assure them that the chances of their becoming infected are remote but that the facility doesn’t want germs spread to other patients. Before they leave the room, make sure they remove protective equipment and wash their hands. Be sure to provide teaching and emotional support.
• No sharing. Don’t use shared equipment, such as electronic thermometers, stethoscopes, and blood pressure cuffs. Each patient should have his own glass or disposable thermometer. If you bring in other equipment, such as a pulse oximeter, don’t lay it on the bed or bed stand and wipe it with appropriate disinfectant before you leave the room.
• Group patients with like infections. Consider grouping people with the same infection near one another and assign designated staff to decrease the chances of cross-contamination.
• Use aseptic technique. As always, use aseptic technique for such procedures as suctioning, catheterizing and inserting intravenous lines. Any breach in aseptic technique may allow pathogens to gain a foothold.
• Know your institution’s policies and procedures for antibiotic use. Your pharmacy and therapeutics, drug utilization, and infection control committees can provide guidelines for matching the narrowest-spectrum antimicrobial with the infective organism.
• Communicate tactfully. In the role of patient advocate, encourage physicians to limit the use of antibiotics. Don’t hesitate to speak up if you think they are prescribing antibiotics indiscriminately.
• Educate patients. Be sure to tell your patient that he should take his antibiotic for the full prescription period, even if he begins to feel better. Also make sure he understands that not all diseases can be treated with antibiotics.
Unfortunately, new antibiotic-resistant organisms continue to appear. Recently, for example, clinicians have witnessed the rise of penicillin-resistant Streptococcus pneumoniae and Neisseria gonorrhoeae, as well as antibiotic-resistant mycobacterium tuberculosis.
Perhaps most alarming, however, is the recent discovery of an S. aureus intermediately resistant to vancomycin (known by the acronym VISA). In mid-1996, clinicians discovered the first such microbe in a Japanese infant’s surgical wound. Closer to home, similar staphylococcus aureus isolates were reported in Michigan and New Jersey.
Both patients had received multiple courses of vancomycin for MRSA infections. The appearance of this isolate signals a dangerous new development. That’s because since the emergence of MRSA in the 1980s, vancomycin has been the drug of choice for treating serious MRSA infections. Now, with the emergence of VISA, the arrival of S. aureus fully resistant to vancomycin (VRSA) is much more likely. This will leave clinicians with virtually no antibiotic to combat this microbe.
To prevent the rise of VRSA and other antibiotic-resistant organisms, use similar techniques for preventing the spread of VRE and MRSA. Among the most important measures: good hand washing, barrier precautions and continued vigilance against the spread of these organisms.
[To receive 2.0 continuing education credits for reading this article, call Michelle Boasten at (330) 253-6368 for further information.]
Subscribe Now for Access
You have reached your article limit for the month. We hope you found our articles both enjoyable and insightful. For information on new subscriptions, product trials, alternative billing arrangements or group and site discounts please call 800-688-2421. We look forward to having you as a long-term member of the Relias Media community.