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Practical Issues in Wound, Skin and Ostomy Management
Staphylococcus aureus is one of the most feared human pathogens, causing a wide range of infections. Most wound care professionals can expect to frequently encounter patients with S. aureus infections. Soft-tissue infections caused by S. aureus include impetigo, cellulitis, and cutaneous abscesses, as well as such life-threatening processes as necrotizing fasciitis and pyomyositis (a hematogenous intramuscular abscess). Serious non-soft-tissue infections include septic arthritis, osteomyelitis, pneumonia, endocarditis, and sepsis.
S. aureus produces various cellular and extracellular factors involved in the pathogenesis of infection. S. aureus protein A, an important surface protein, helps the organism resist phagocytosis. Also, S. aureus produces several cytotoxins and enzymes that contribute to infection spread and severity. In addition, some strains produce toxins (including toxic shock syndrome toxin-1) that function as superantigens—molecules that nonspecifically trigger release of large amounts of cytokines, leading to a sepsislike condition. Taken together, such factors combine to make S. aureus a dangerous pathogen.
When penicillin was introduced in the 1940s, virtually all S. aureus isolates were sensitive to that drug. But soon thereafter, S. aureus strains that produced a β-lactamase enzyme capable of inactivating penicillin became widespread. During the 1950s, outbreaks of penicillin-resistant S. aureus occurred in many U.S. hospitals. Introduction of penicillinase-resistant antibiotics, such as methicillin and oxacillin, temporarily restored the ability to treat all strains of this pathogen using penicillin antibiotics. The first strain of methicillin-resistant S. aureus (MRSA) was described in 1961 shortly after introduction of penicillinase-resistant antibiotics.
The mechanism of methicillin resistance involves a mutation in one of the bacterial cell-wall proteins to which penicillins must bind to kill the bacterium. This mutation renders the organism resistant to all penicillins and penems and almost all cephalosporins.
MRSA incidence has increased steadily to the point where it currently constitutes up to 60% of S. aureus isolates in many U.S. hospitals. These organisms commonly carry genetic material that makes them resistant to various non-β lactam antibiotics as well, leading some to suggest that the term MRSA should stand for multiply resistant S. aureus.
S. aureus has continued to mutate in the face of persistent antibiotic pressure. Vancomycin-intermediate S. aureus (VISA) was described in 1997; vancomycin-resistant S. aureus (VRSA), in 2003. Fortunately, these two strains remain rare and haven’t become established pathogens. (See Strains of antibiotic-resistant S. aureus by clicking the PDF icon above.)
Although MRSA initially arose and spread within healthcare settings (chiefly acute-care hospitals), a community-based variant was described in 1998. Called community-
acquired MRSA (CA-MRSA), this variant differs from healthcare-associated MRSA (HCA-MRSA) in more ways than the acquisition site. CA-MRSA occurs predominately in otherwise healthy children and young adults.
It most commonly presents as recurrent cutaneous abscesses, although life-threatening infections (such as necrotizing fasciitis and pneumonia) also have occurred. The propensity to cause cutaneous abscesses isn’t fully understood but may relate partly to production of the Panton-Valentine toxin by many CA-MRSA isolates.
In contrast, HCA-MRSA afflicts mainly older patients, particularly those with chronic illnesses, including chronic wounds. It typically causes wound infections, urinary tract infections, pneumonia, and bacteremia.
Besides these epidemiologic and clinical differences, many CA-MRSA isolates derive from a single clone, known as clone USA 300, whereas HCA-MRSA is composed of multiple non-USA 300 clones. Finally, many CA-MRSA isolates are sensitive to non-β
lactam antibiotics, whereas most HCA-MRSA isolates resist multiple antibiotics. More recently, the distinction between CA-MRSA and HCA-MRSA has been blurred as evidence emerges that CA-MRSA now is being transmitted in healthcare settings as well as in the community.
Staphylococci are frequent colonizers of humans. Common colonization sites include the skin, anterior nares, axillae, and inguinal regions. Individuals can be colonized continuously or transiently, with nasal carriage rates varying from 20% to 40%. Most S. aureus infections result from the strain carried by the infected patient.
Three patterns of S. aureus carriage exist in humans:
• 20% of individuals are continuously colonized.
• 30% of individuals are intermittently colonized.
• 50% of individuals are never colonized.
The highest carriage rates occur in patients receiving frequent injections (such as insulin-dependent diabetics, hemodialysis patients, and I.V. drug users) and those with chronic skin conditions (for instance, psoriasis or eczema). In the general population, MRSA carriage rates have increased to 1% or 2%, with clinical consequences hinging on the colonizing strain (CA-MRSA versus HCA-MRSA) and host characteristics. The most consistent carriage site is the anterior nares, but many other sites may carry this pathogen, including the axillae, inguinal regions, and perirectal area.
Therapy for MRSA infection depends on the infection location and antibiotic sensitivity of the infecting strain.
• Cutaneous abscesses are treated by incision and drainage; antibiotics play a secondary role to adequate drainage.
• Therapy for necrotizing fasciitis caused by MRSA involves aggressive debridement with removal of all necrotic tissue, plus adequate antibiotic therapy. Typically, patients require serial debridement followed by subsequent careful wound care, often with eventual skin grafting.
• Pyomyositis treatment entails drainage of the muscle abscess (which sometimes can be done with percutaneous tube placement instead of open drainage), plus appropriate antibiotic therapy.
Vancomycin has been the mainstay of I.V. therapy for MRSA for decades, but some clinicians are concerned that its effectiveness may be declining due to slowly increasing minimum inhibitory concentrations (the minimum concentration of an
antibiotic needed to inhibit pathogen growth). Other parenteral options have emerged in the last few years. (See I.V. drugs used to treat MRSA by clicking the PDF icon above.) Several oral antibiotics also are available for MRSA treatment. (See Oral agents used to treat MRSA by clicking the PDF icon above.)
Knowing the antibiotic sensitivity pattern of the infecting MRSA strain is crucial to ensuring that the patient receives an appropriate antibiotic. Treatment duration for soft-
tissue infections usually ranges from 7 to 14 days, but bacteremia and bone or joint infections call for more prolonged therapy.
Because the carrier state increases the risk of subsequent S. aureus infection, efforts have been made to eradicate carriage. Unfortunately, this has proven to be difficult. A commonly used regimen involves 5 days of twice-daily mupirocin nasal ointment with either chlorhexidine gluconate showers or immersion up to the neck in a dilute bleach solution. However, success in eliminating carriage is limited, although the bleach bath seems to improve eradication rates better than other modalities.
How best to control MRSA spread within hospitals is controversial. Some experts advocate an aggressive, “search and destroy” approach involving screening all patients for nasal carriage on admission and initiating contact precautions with subsequent decolonization efforts. Others focus on improving the overall level of hand hygiene and other general infection-control measures, arguing that nasal screening misses at least 20% of MRSA-colonized patients and thus gives an unwarranted sense of security.
Many hospitals use a mixed approach, screening patients suspected to be at high risk for MRSA carriage (such as those admitted from extended-care facilities or to the intensive care unit), while simultaneously trying to improve hand hygiene and general infection-control measures. Recent data suggest MRSA colonization and infection rates have stopped increasing and are beginning to decline.
MRSA is one of the most problematic pathogens encountered on a regular basis, and among the most dangerous pathogens we face. While some MRSA infections are relatively mild, many are serious or life-threatening. Severe soft-tissue infections, such as necrotizing fasciitis and pyomyositis, require surgical debridement or drainage, appropriate antibiotic therapy, and assistance from a wound-care professional to achieve optimal outcomes. n
Selected references
Calfee DP. The epidemiology, treatment and prevention of transmission of methicillin-resistant Staphylococcus aureus. J Infus Nurs. 2011 Nov-Dec;34(6):359-64.
DeLeo FR, Otto M, Kreiswirth BN, Chambers HF. Community-associated meticillin-resistant Staphylococcus aureus. Lancet. 2010 May 1;375(9725): 1557-68.
Dryden MS. Complicated skin and soft tissue infection. J Antimicrob Chemother. 2010 Nov;65 Suppl 3:iii35-44.
Ippolito G, Leone S, Lauria FN, et al. Methicillin-resistant Staphylococcus aureus: the superbug. Int J Infect Dis. 2010 Oct;14 Suppl 4:S7-11.
Landrum ML, Neumann C, Cook C, et al. Epidemiology of Staphylococcus aureus blood and skin and soft tissue infections in the US military health system, 2005-2010. JAMA. July 4;308:50-9.
Lee AS, Huttner B, Harbarth S. Control of methicillin-resistant Staphylococcus aureus. Infect Dis Clin North Am. 2011 Mar;25(1):155-79.
Moellering RC Jr. MRSA: the first half century. J Antimicrob Chemother. 2012 Jan;67(1):4-11.
Otter JA, French GL. Community-associated meticillin-resistant Staphylococcus aureus strains as a cause of healthcare-associated infection. J Hosp Infect. 2011 Nov:79(3):189-93.
Rivera AM, Boucher HW. Current concepts in antimicrobial therapy against select gram-positive organisms: methicillin-resistant Staphylococcus aureus, penicillin-resistant pneumococci, and vancomycin-resistant enterococci. Mayo Clin Proc. 2011 Dec;86(12):1230-43.
Simor AE. Staphylococcal decolonization: an effective strategy for prevention of infection? Lancet Infect Dis. 2011 Dec;11(12):952-62.
Joseph G. Garner is director of the infectious disease division and hospital epidemiologist at the Hospital of Central Connecticut and a professor of medicine at the University of Connecticut.
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The new research has identified (see below) a peptide found from the Komodo dragon (Varanus komodoensis), called VK25, which appears to be useful as a cationic antimicrobial peptide (CAMP). There is currently considerable interest in antimicrobial peptides in a world where antibiotic effectiveness is in decline. These peptides are potent, broad spectrum antibiotics which demonstrate potential as novel therapeutic agents. (more…)
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A 39-year-old woman presents to the ED with leg pain and fever. She initially noted redness and pain above her knee 2 weeks ago and was evaluated at an outside hospital. She completed a 10-day course of oral antibiotics for cellulitis. Over the last two days, she has had progressive leg swelling of her entire right thigh. The pain is now so severe that she is having difficulty walking. Her past medical history is negative for diabetes mellitus, chronic liver disease, or alcohol and IV drug use.
On exam, she is febrile to 102.7 F, heart rate is 96 bpm, and blood pressure is 112/65. She has a 12 cm area of faint erythema on her right thigh and tenderness to palpation of her entire right leg with diffuse edema. There is no ecchymosis or bullae formation. (more…)
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By Janet Wolfson, PT, CWS, CLT-LANA
After landing my dream job as the wound care coordinator at an inpatient rehabilitation facility (IRF), I found myself trying to determine how much healing could be achieved for our more challenging patients, given the constraints of reimbursement and what can be done in the typical 10 to 14 days of a patient stay.
Here’s an example of how I worked with our team to help one of these challenging patients. (more…)
Read MoreBy Darlene Hanson, PhD, RN; Diane Langemo, PhD, RN, FAAN; Patricia Thompson, MS, RN; Julie Anderson, PhD, RN; and Keith Swanson, MD
Cellulitis is an acute, painful, and potentially serious spreading bacterial skin infection that affects mainly the subcutaneous and dermal layers. Usually of an acute onset, it’s marked by redness, warmth, swelling, and tenderness. Borders of the affected skin are characteristically irregular. Although cellulitis may occur in many body areas, this article discusses the most common location—the lower limb. (more…)
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According to the National Pressure Ulcer Advisory Panel (NPUAP), incidence density is the best quality measure of pressure-ulcer prevention programs. Pressure-ulcer incidence density is calculated by dividing the number of inpatients who develop a new pressure ulcer by 1,000 patient days. Using the larger denominator of patient days allows fair comparisons between institutions of all sizes. (more…)
Read MoreBy Ronnel Alumia, BSN, RN, WCC, CWCN, OMS
Achieving excellent wound care outcomes can be challenging, given the growing number of high-risk patients admitted to healthcare facilities today. Many of these patients have comorbidities, such as obesity, diabetes, renal disease, smoking, chronic obstructive pulmonary disease, and poor nutritional status. These conditions reduce wound-healing ability. (more…)
Read MoreResearchers have found that using hybrid 67Ga single-photon emission computed tomography and X-ray computed tomography (SPECT/CT) imaging combined with a bedside percutaneous bone puncture in patients with a positive scan is “accurate and safe” for diagnosing osteomyelitis in patients with diabetes who have a foot ulcer without signs of soft-tissue infection.
The new method, which avoids an invasive bone biopsy, has a sensitivity of 88% and a specificity of 93.6%. In the study of 55 patients, antibiotic treatment was avoided in 55% of suspected cases.
“Diagnosing diabetic foot osteomyelitis in patients without signs of soft tissue infection by coupling hybrid 67Ga SPECT/CT with bedside percutaneous bone puncture,” published by Diabetes Care, followed patients for at least a year.
The strains of methicillin-resistant Staphylococcus aureus (MRSA) differ in the hospital and community settings, and both are likely to coexist in the future, according to a study in PLOS Pathogens.
“Hospital-community interactions foster coexistence between methicillin-resistant strains of Staphylococcus aureus” notes that previously it was thought that the more invasive community strains would become more prevalent (and even eliminate) hospital strains. This new information could have significant consequences for public health because of the differences in the resistance of the two strains.
Despite increasing activities to prevent the spread of Clostridium difficile, infection from C. difficile remains a problem in healthcare facilities, according to a survey of infection preventionists by the Association for Professionals in Infection Control and Epidemiology (APIC).
The survey found that 70% of preventionists have adopted additional interventions in their healthcare facilities since March 2010, but only 42% have seen a decline in C. difficile infection rates; 43% saw no decline.
A total of 1,087 APIC members completed the survey in January 2013. The survey also found that more than 92% of respondents have increased emphasis on environmental cleaning and equipment decontamination practices, but 64% said they rely on observation, rather than more accurate and reliable monitoring technologies, to assess cleaning effectiveness.
In addition, 60% of respondents have antimicrobial stewardship programs at their facilities, compared with 52% in 2010. Such programs promote the appropriate use of antibiotics, which can help reduce the risk of C. difficile infection.
According to the Centers for Disease Control and Prevention, diarrhea caused by C. difficile is linked to 14,000 American deaths each year.
Mast cells may not play significant role in wound healing
“Evidence that mast cells are not required for healing of splinted cutaneous excisional wounds in mice,” published in PLOS One, analyzed wound healing in three types of genetically mast-deficient mice and found they reepithelialized their wounds at rates similar to control mice. At the time of closure, the researchers found that scars in all the mice groups were similar in both “quality of collagen deposition and maturity of collagen fibers.” The findings fail to support the previously held belief that mast cells are important in wound healing.
Nonremovable casts that relieve pressure are more effective than removable casts or dressings alone for the treatment of plantar foot ulcers caused by diabetes, according to an analysis of clinical trials.
The authors of “Pressure-relieving interventions for treating diabetic foot ulcers,” published by The Cochrane Library, reviewed 14 randomized clinical trials that included 709 participants. Nonremovable pressure-relieving casts were compared to dressings alone, temporary therapeutic shoes, removable pressure-relieving devices, and surgical lengthening of the Achilles tendon.
The study also notes that when combined with Achilles tendon lengthening, nonremovable devices were more successful in one forefoot ulcer study than the use of a nonremovable cast alone.
Most studies were from the United States (five) and Italy (five), with Germany, the Netherlands, Australia, and India each contributing one study.
“Prolonged antibiotic treatment in long-term care: Role of the prescriber,” published by JAMA Internal Medicine, found that the preferences of prescribers, rather than patient characteristics, drive antibiotic treatment.
The study of 66,901 patients from 630 long-term care facilities found that 77.8%
received a course of antibiotics. The most common length (41%) was 7 days, but the length exceeded 7 days in 44.9% of patients. Patient characteristics were similar among short-, average-, and long-duration prescribers.
The study authors conclude: “Future trials should evaluate antibiotic stewardship interventions targeting prescriber preferences to systematically shorten average treatment durations to reduce the complications, costs, and resistance associated with antibiotic overuse.”
“Electrophysical therapy for managing diabetic foot ulcers: A systematic review” concludes that electrophysical therapy is potentially beneficial because in each randomized clinical trial it outperformed the control or sham electrical stimulation.
The authors of the study in International Wound Journal reviewed eight trials with a combined total of 325 patients. Five studies were on electrical stimulation, two on phototherapy, and one on ultrasound. Because of the small number of trials, the possibility of harmful effects can’t be ruled out, and the authors recommend “high-quality trials with larger sample sizes.”
“Geographic variation in Medicare spending and mortality for diabetic patients with foot ulcers and amputations” reports healthcare spending and mortality rates vary “considerably” across the United States.
The study in Journal of Diabetes and Its Complications found that higher spending wasn’t associated with a significant reduction in 1-year patient mortality. In addition, rates of hospital admission were associated with higher per capita spending and higher mortality rates for patients.
An individualized, home-based progressive resistance exercise program improves upper-limb volume and circumference and quality of life in postmastectomy patients with lymphedema, according to a study published in the Journal of Rehabilitation Research and Development.
“Effect of home-based exercise program on lymphedema and quality of life in female postmastectomy patients: Pre-post intervention study” included 32 women who participated in an 8-week program. The women received education about the program and an initial training session from a physiotherapist. They practiced the exercise sequence and received a program and logbook once their performance was satisfactory. Patients were told to increase weight only when two sets of 15 repetitions became easy to perform.
Read MoreBy Carrie Carls, BSN, RN, CWOCN, CHRN; Michael Molyneaux, MD; and William Ryan, CHT
Every year, 1.9% of patients with diabetes develop foot ulcers. Of those, 15% to 20% undergo an amputation within 5 years of ulcer onset. During their lifetimes, an estimated 25% of diabetic patients develop a foot ulcer. This article discusses use of hyperbaric oxygen therapy (HBOT) in treating diabetic foot ulcers, presenting several case studies.
HBOT involves intermittent administration of 100% oxygen inhaled at a pressure greater than sea level. It may be given in a:
• multi-place chamber (used to treat multiple patients at the same time), compressed to depth by air as the patient breathes 100% oxygen through a face mask or hood (more…)
The new Essen Rotary swabbing technique takes a few seconds longer to perform than traditional techniques, but improves bacterial count accuracy in patients with chronic leg ulcers, according to a study published by Wounds International.
“Evaluation of the Essen Rotary as a new technique for bacterial swabs: Results of a prospective controlled clinical investigation in 50 patients with chronic leg ulcers” reports that Essen Rotary detected significantly more bacteria compared to standard techniques and was the only one to identify five patients with methicillin-resistant Staphylococcus aureus (MRSA), compared to three detected by other techniques.
The Essen Rotary technique samples a larger surface area of the wound, which is beneficial for detecting MRSA.
“The Essen Rotary may become the new gold standard in routinely taken bacteriological swabs especially for MRSA screenings in patients with chronic leg ulcers,” the study authors write.
A study presented at the American Diabetes Association 72nd Scientific Sessions found lowering HbA1c an average of 0.8% (from a mean of 7.8% to 7.0%, the treatment target) reduced the risk of cardiovascular death by 45% in patients with type
2 diabetes.
The absolute risk of mortality from a cardiovascular event was 9.9 events per 1,000 person-years in patients with decreasing HbA1c compared to 17.8 events in patients with stable or increasing HbA1c.
“HbA1c reduction and risk of cardiovascular diseases in type 2 diabetes: An observational study from the Swedish NDR” examined data from 18,035 patients in the Swedish National Diabetes Register.
The Centers for Medicare & Medicaid Services (CMS) has enhanced two websites designed to help the public make informed choices about their health care.
Hospital Compare and Nursing Home Compare now have better navigation and new comparison tools. The two sites include data on quality measures, such as frequency of hospital-acquired infections, and allow the user to compare hospitals on these measures.
Improvements include easy-to-use maps for locating hospitals, a new search function that enables the user to input the name of a hospital, and glossaries that are easier to understand. It’s now also possible to access the data on the sites through mobile applications.
CMS maintains the websites, which are helpful for anyone who wants to compare facilities, not just patients on Medicare or Medicaid.
For more information, read the article in Healthcare IT News.
The Institute of Medicine (IOM) released “Accelerating the development of new drugs and diagnostics: Maximizing the impact of the Cures Acceleration Network—Workshop Summary.” The report is a summary of a forum that brought together members of federal government agencies, the private sector, academia, and advocacy groups to explore options and opportunities in the implementation of Cures Acceleration Network (CAN). The newly developed CAN has the potential to stimulate widespread changes in the National Institutes of Health and drug development in general.
As a result of two extensive literature reviews, a researcher at the University of Missouri found that emphasizing quality of life—not just reducing swelling—is important for patients with lymphedema. Many providers and insurance companies base treatment on the degree of edema, but the volume of fluid doesn’t always correspond with the patients’ discomfort. Instead, an individualized plan of care should be developed.
The researchers found that Complete Decongestive Therapy (CDT), a comprehensive approach for treating lymphedema that includes skin and nail care, exercise, manual lymphatic drainage, and compression, may be the best form of specialized lymphedema management. For more information about CDT, watch for the November/December issue of Wound Care Advisor.
An article about a case of the plague in Oregon has appeared on Huffington Post. A welder contracted the disease as a result of unsuccessfully removing a mouse from a stray cat’s mouth. Part of his hands have, in the words of the article, “darkened to the color of charcoal.” Later tests confirmed the cat had the plague.
Plague cases are rare in the United States. According to the Centers for Disease Control and Prevention, an average of 7 human cases are reported each year, with a range of 1 to 17 cases. Antibiotics have significantly reduced morality. About half of cases occur in people ages 12 to 45.
“Optimal use of negative pressure wound therapy for skin grafts,” published by International Wound Journal, reviews expert opinion and scientific evidence related to the use of negative pressure wound therapy with reticulated open-cell foam for securing split-thickness skin grafts.
The article covers wound preparation, treatment criteria and goals, economic value, and case studies. The authors conclude that the therapy has many benefits, but note that future studies are needed “to better measure the expanding treatment goals associated with graft care, including increased patient satisfaction, increased patience compliance and improved clinical outcomes.”
Researchers have identified that aberrantly expressed microRNAs inhibit healing of chronic venous ulcers, according to a study in The Journal of Biological Chemistry.
Six microRNAs were plentiful in 10 patients with chronic venous ulcers. The microRNAs target genes important in healing the ulcers. In an article about the study, one of the researchers said, “The more we know about the molecular mechanisms that contribute to [the development of venous ulcers], the more we can rationally develop both diagnostic tools and new therapies.”
Both patients with diabetes and those without are at risk for hemodialysis-related foot ulcers, according to a study published by International Wound Journal.
Researchers assessed 57 patients for ulcer risk factors (peripheral neuropathy, peripheral arterial disease, and foot pathology, such as claw toes, hallux valgus, prominent metatarsal heads, corns, callosities, and nail pathologies) at baseline, and noted mortality 3 years later.
In all, 79% of patients had foot pathology at baseline, and 18% of patients without diabetes had peripheral neuropathy. Peripheral arterial disease was present in 45% of diabetic and 30% of nondiabetic patients. Nearly half (49%) of patients had two or more risk factors. Only 12% of patients had no risk factors. The presence of peripheral arterial disease and peripheral neuropathy increased risk of mortality.
The authors of “Prevalence of risk factors for foot ulceration in a general haemodialysis population” state that the high prevalence of risk factors in nondiabetic patients indicates that they are at risk for developing foot ulcers.
A study in Emerging Infectious Diseases found that older age, living in a nursing home, severe bacteremia, and organ impairment increase the risk of death from methicillin-resistant Staphylococcus aureus (MRSA) bacteremia.
Consultation with a specialist in infectious disease lowers the risk of death, and MRSA strain types weren’t associated with mortality.
“Predicting risk for death from MRSA bacteremia” studied 699 incidents of blood infection from 603 patients who had MRSA bacteremia.