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.
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.
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.
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)
Infection Prevention and Control in the Podiatric Medical Setting
Challenges to Providing Consistently Safe Care
Unsafe practices are an underestimated contributor to the disease burden of bloodborne viruses. Outbreaks associated with failures in basic infection prevention have been identified in nonhospital settings with increased frequency in the United States during the past 15 years, representing an alarming trend and indicating that the challenge of providing consistently safe care is not always met. As has been the case with most medical specialties, public health investigations by state and local health departments, and the Centers for Disease Control and Prevention, have identified some instances of unsafe practices that have placed podiatric medical patients at risk for viral, bacterial, and fungal infections. All health-care providers, including podiatric physicians, must make infection prevention a priority in any setting in which care is delivered.
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)
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.
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.
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.
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.
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.
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.
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.
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.
Tedizolid and Linezolid for Treatment of Acute Bacterial Skin and Skin Structure Infections of the Lower Extremity versus Non–Lower-Extremity Infections
Pooled Analysis of Two Phase 3 Trials
Tedizolid phosphate, the prodrug of the oxazolidinone tedizolid, has been approved in a number of countries, including the United States, those in the European Union, and Canada, for treatment of patients with acute bacterial skin and skin structure infections (ABSSSI). Two phase 3 trials demonstrated the noninferior efficacy of tedizolid (200 mg once daily for 6 days) to linezolid (600 mg twice daily for 10 days) in patients with ABSSSI. Because of the challenges of treating lower-extremity ABSSSI, the efficacy and safety of tedizolid and linezolid for treating lower-extremity versus non–lower-extremity infections were compared.
This was a post hoc analysis of pooled data from patients with lower-extremity infections enrolled in two phase 3 studies, ESTABLISH-1 (NCT01170221) and ESTABLISH-2 (NCT01421511), comparing tedizolid to linezolid in patients with ABSSSI.
Lower-extremity ABSSSI were present in 40.7% of tedizolid-treated and 42.2% of linezolid-treated patients. Methicillin-resistant Staphylococcus aureus (MRSA) was present in 34.7% of all patients with a baseline causative pathogen. Early clinical responses at 48 to 72 hours and investigator-assessed responses at the post-therapy evaluation were similar between tedizolid and linezolid, regardless of ABSSSI type. With both treatments, the early clinical response was slightly higher in patients with non–lower-extremity infection than in those with lower-extremity ABSSSI (tedizolid, 84.8% versus 77.0%; linezolid, 81.4% versus 76.6%, respectively); however, by the post-therapy evaluation visit, response rates were similar (tedizolid, 87.1% versus 86.3%; linezolid, 86.6% versus 87.2%, respectively). Gastrointestinal adverse events and low platelet counts were observed more frequently with linezolid treatment.
Post-therapy evaluations showed that the clinical response of lower-extremity ABSSSI to tedizolid and linezolid was comparable to that of ABSSSI in other locations. A short 6-day course of once-daily tedizolid was as effective as a 10-day course of twice-daily linezolid in treating patients with lower-extremity ABSSSI.