Search Results
Therapeutic Options for Diabetic Foot Infections
A Review with an Emphasis on Tissue Penetration Characteristics
Foot complications are common in diabetic patients; foot ulcers are among the more serious consequences. These ulcers frequently become infected, and if not treated promptly and appropriately, diabetic foot infections can lead to septic gangrene and amputation. Foot infections may be classified as mild, moderate, or severe; this largely determines the approach to therapy. Staphylococcus aureus is the most common pathogen in these infections, and the increasing incidence of methicillin-resistant S aureus during the past two decades has further complicated antibiotic treatment. Chronic infections are often polymicrobial. Physiologic changes, and local and systemic inflammation, can affect the plasma and tissue pharmacokinetics of antimicrobial agents in diabetic patients, leading to impaired target-site penetration. Knowledge of the serum and tissue concentrations of antibiotics in diabetic patients is, therefore, important for choosing the optimal drug and dose. This article reviews the commonly used therapeutic options for treatment, including many newer antibiotics developed to target multidrug-resistant gram-positive bacteria, and includes available data relating specifically to the tissue penetration of these agents. (J Am Podiatr Med Assoc 100(1): 52–63, 2010)
The elderly make more frequent use of general podiatric medical services than the younger population. It is therefore important for podiatric physicians to become familiar with the general principles of infectious disease as applied to an elderly population, which is susceptible to a wider spectrum of disease with more subtle and unusual clinical signs and symptoms. This article reviews the diagnosis and evaluation of suspected infection, appropriate laboratory testing, patterns of specific infectious disease syndromes, and antibiotic use in the elderly. (J Am Podiatr Med Assoc 94(2): 126-134, 2004)
Osteolysis, caused by active resorption of bone matrix by osteoclasts, can be primary or can develop secondary to a variety of disease processes. An elevated level of inflammatory cytokines in the local milieu and increased blood flow secondary to infection or autonomic neuropathy stimulate the osteoclasts and cause bone loss in the diabetic foot. Charcot's neuroarthropathy and osteomyelitis are well-known foot complications of diabetes, and secondary osteolysis has largely been underappreciated and, hence, underreported. Plain radiographs, an initial component in the evaluation of the diabetic foot, may not successfully differentiate secondary osteolysis from osteomyelitis. We describe a patient with phalangeal osteolysis secondary to soft-tissue infection in whom a correct and timely diagnosis helped avoid unnecessary surgical interventions.
Background:
Selecting empirical therapy for a diabetic foot infection (DFI) requires knowing how likely infection with Pseudomonas aeruginosa is in a particular patient. We designed this study to define the risk factors associated with P aeruginosa in DFI.
Methods:
We performed a preplanned microbiological subanalysis of data from a study assessing the effects of treatment with intralesional epidermal growth factor for diabetic foot wounds in patients in Turkey between January 1, 2012, and December 31, 2013. Patients were screened for risk factors, and the data of enrolled individuals were recorded in custom-designed patient data forms. Factors affecting P aeruginosa isolation were evaluated by univariate and multivariate logistic regression analyses, with statistical significance set at P < .05.
Results:
There were 174 patients enrolled in the main study. Statistical analysis was performed in 90 evaluable patients for whom we had microbiological assessments. Cultures were sterile in 19 patients, and 89 bacterial isolates were found in the other 71. The most frequently isolated bacteria were P aeruginosa (n = 23, 25.8%) and Staphylococcus aureus (n = 12, 13.5%). Previous lower-extremity amputation and a history of using active wound dressings were the only statistically significant independent risk factors for the isolation of P aeruginosa in these DFIs.
Conclusions:
This retrospective study provides some information on risk factors for infection with this difficult pathogen in patients with DFI. We need prospective studies in various parts of the world to better define this issue.
We report a case of an unusual and unsuspected chronic infection creating a soft-tissue mass in the foot of a 35-year-old woman. The causative agent, Mycobacterium gordonae, is usually encountered as a laboratory contaminant. Only rarely does it manifest as a clinical infection. The patient’s presumed predisposing risk factor was a history of barefoot gardening. An iatrogenic source, corticosteroid injections, was also considered. (J Am Podiatr Med Assoc 98(4): 311–313, 2008)
Wound Healing and Infection in Nail Matrix Phenolization Wounds
Does Topical Medication Make a Difference?
After nail matrix ablation using phenolization, a medicated wound dressing (10% povidone iodine), an amorphous hydrogel dressing (Intrasite Gel), and a control dressing (paraffin gauze) were evaluated. Forty-two participants, randomly divided into three dressing groups, were evaluated. Healing time did not differ between the 10% povidone iodine (33 days), amorphous hydrogel (33 days), and the control dressing (34 days). For all groups, the clinical infection rate was lower than in previous studies, and there was no clinical difference between groups (one infection in the povidone iodine and control groups; none in the amorphous hydrogel group). However, in the amorphous hydrogel group, other complications, such as hypergranulation, were more likely. This investigation indicated that medicated or hydrogel dressings did not enhance the rate of healing or decrease infection rates. (J Am Podiatr Med Assoc 91(5): 230-233, 2001)
Diabetic foot disease frequently leads to substantial long-term complications, imposing a huge socioeconomic burden on available resources and health-care systems. Peripheral neuropathy, repetitive trauma, and peripheral vascular disease are common underlying pathways that lead to skin breakdown, often setting the stage for limb-threatening infection. Individuals with diabetes presenting with foot infection warrant optimal surgical management to affect limb salvage and prevent amputation; aggressive short-term and meticulous long-term care plans are required. In addition, the initial surgical intervention or series of interventions must be coupled with appropriate systemic metabolic management as part of an integrated, multidisciplinary team. Such teams typically include multiple medical, surgical, and nursing specialties across a variety of public and private health-care systems. This article presents a stepwise approach to the diagnosis and treatment of diabetic foot infections with emphasis on the appropriate use of surgical interventions and includes the following key elements: incision, wound investigation, debridement, wound irrigation and lavage, and definitive wound closure. (J Am Podiatr Med Assoc 100(5): 401–405, 2010)
Background
Diabetic foot infection (DFI) is a serious, difficult-to-treat infection, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin has been the standard treatment for MRSA infection, but lower response rates in MRSA skin infections have been reported. This analysis assessed the outcome and safety of daptomycin therapy in patients with a DFI caused by MRSA.
Methods
Using the Cubicin Outcomes Registry and Experience and the European Cubicin Outcomes Registry and Experience (2006–2009), 79 patients with MRSA DFI were identified and included in this analysis.
Results
In the 74 evaluable patients, daptomycin was administered at a median dose of 4.8 mg/kg primarily every 24 hours (85.1%) and for a median of 15.0 days. Overall, 77.0% of the patients (57 of 74) received initial therapy with activity against MRSA; however, of patients receiving daptomycin as second-line therapy (n = 31), only 45.2% were treated with an antibiotic agent active against MRSA. The overall clinical success and treatment failure rates were 89.2% and 10.8%, respectively. Success with daptomycin therapy was higher in patients who had surgery and in those whose initial therapy was daptomycin. Eleven patients had 14 adverse events, two of which were possibly related to daptomycin use and led to discontinuation.
Conclusions
In a large real-world cohort of patients with MRSA DFI, daptomycin therapy was shown to be generally well tolerated and effective. The use of an anti-MRSA antibiotic agent should be considered when implementing first-line antibiotic drug therapy for DFI in countries where MRSA is common to avoid inappropriate empirical treatment and potential negative effects on outcomes.
Surgical management of hallux rigidus using a polyvinyl alcohol synthetic cartilage implant has gained popularity among foot and ankle surgeons. Although uncommon, appropriate diagnosis and management of a periprosthetic implant infection is critical in limiting morbidity. We present a case report and staged technique for converting a first metatarsal synthetic cartilage hemiarthroplasty to arthrodesis in the setting of a periprosthetic joint infection.
Background
Onychomycosis is estimated to occur in approximately 10% of the global population, with most cases caused by Trichophyton rubrum. Some persistent onychomycosis is caused by mixed infections of T rubrum and one or more co-infecting nondermatophyte molds (NDMs). In onychomycosis, T rubrum strain types may naturally switch and may also be triggered to switch in response to antifungal therapy. T rubrum strain types in mixed infections of onychomycosis have not been characterized.
Methods
T rubrum DNA strains in mixed infections of onychomycosis containing co-infecting NDMs were compared with a baseline North American population through polymerase chain reaction amplification of ribosomal DNA tandemly repetitive subelements (TRSs) 1 and 2. The baseline DNA strain types were determined from 102 clinical isolates of T rubrum. The T rubrum DNA strain types from mixed infections were determined from 63 repeated toenail samples from 15 patients.
Results
Two unique TRS-2 types among the clinical isolates contributed to four unique TRS-1 and TRS-2 strain types. Six TRS-1 and TRS-2 strain types represented 92% of the clinical isolates of T rubrum. Four TRS-1 and TRS-2 strain types accounted for 100% of the T rubrum within mixed infections.
Conclusions
Four unique North American T rubrum strains were identified. In support of a shared ancestry, the T rubrum DNA strain types found in mixed infections with NDMs were among the most abundant types. A population of T rubrum strains in mixed infections of onychomycosis has been characterized, with more than one strain detected in some nails. The presence of a co-infecting NDM in mixed infections may contribute to failed therapy by stabilizing the T rubrum strain type, possibly preventing the antifungal therapy–induced strain type switching observed with infections caused by T rubrum alone.
