Search Results
Pseudomonas aeruginosa
An Uncommon Cause of Diabetic Foot Infection
Background
Pseudomonas aeruginosa has traditionally been considered a common pathogen in diabetic foot infection (DFI), yet the 2012 Infectious Diseases Society of America guideline for DFI states that “empiric therapy directed at P aeruginosa is usually unnecessary.” The objective of this study was to evaluate the frequency of P aeruginosa isolated from bone or tissue cultures from patients with DFI.
Methods
This study is a cross-sectional survey of diabetic patients presenting with a foot infection to an urban county hospital between July 1, 2012, and December 31, 2013. All of the patients had at least one debridement procedure during which tissue or bone cultures from operative or bedside debridements were obtained. The χ2 test and the t test of means were used to determine relationships between variables and the frequency of P aeruginosa in culture.
Results
The median number of bacteria isolated from DFI was two. Streptococcus spp and Staphylococcus aureus were the most commonly isolated organisms; P aeruginosa was isolated in only five of 112 patients (4.5%). The presence of P aeruginosa was not associated with the patient's age, glycosylated hemoglobin level, tobacco abuse, the presence of osteomyelitis, a prescription for antibiotic drugs in the preceding 3 months, or the type of operative procedure.
Conclusions
Pseudomonas aeruginosa was an infrequent isolate from DFI in this urban, underserved diabetic population. The presence of P aeruginosa was not associated with any measured risk factors. By introducing a clinical practice guideline, we hope to discourage frontline providers from using routine antipseudomonal antibiotic drugs for DFI.
Fever is an active yet nonspecific response of the body to infections and other insults that cause immune cells to release cytokines, resulting in a brain prostanoid–mediated rise in body temperature. The causes, types, clinical management, and postoperative consequences of fever are reviewed in this article. Physicians use fever as a clinical sign for diagnoses and prognoses, but “fevers of unknown origin” continue to be problematic. Fevers that arise 1 or 2 days after surgery are usually due to stress and trauma, but later postoperative fevers often have more serious causes and consequences, such as wound infection. Fever is commonly encountered by podiatric physicians and surgeons, and certain procedures with the lower extremity are more likely to eventuate in fever. (J Am Podiatr Med Assoc 100(4): 281–290, 2010)
Background
Stenotrophomonas maltophilia is an uncommon gram-negative bacterium often found in individuals with long-standing broad-spectrum antibiotic use or catheter use; individuals undergoing hemodialysis; and individuals with prolonged respiratory disease, specifically, cystic fibrosis. To our knowledge, there are few reported cases of S maltophilia being the causative pathogen of infection in a diabetic foot wound.
Methods
Following multiple surgical procedures and deep tissue cultures, S maltophilia was determined to be a secondary opportunistic colonizer of the wound, necessitating a change in antibiotic therapy.
Results
The cultured pathogen was sensitive to ceftazidime, levofloxacin, and trimethoprim-sulfamethoxazole. The treatment team chose to use ceftazidime, as it also provided antibiotic coverage for the initial wound and blood cultures. Change in antibiotic therapy was initiated following multiple surgical procedures and angioplasty of the lower limb. The patient was discharged with a peripheral intravenous central catheter for outpatient antibiotic therapy.
Conclusions
Prolonged exposure to broad-spectrum antibiotics in individuals with multiple comorbidities including diabetes mellitus provides an advantageous environment for growth of uncommon multidrug-resistant organisms. Stenotrophomonas maltophilia may complicate the treatment of diabetic foot infections as an opportunistic pathogen. Understanding the implication of long-term broad-spectrum antibiotic treatment in the diabetic patient is important in managing postoperative complications and determining the correct course of treatment. The emergence of atypical pathogens in diabetic wounds must be managed appropriately.
Background: Onychomycosis, or fungal nail infection, is the cause of 50% of onychopathies seen by podiatric physicians. This pathology is accompanied by a negative psychosocial component because of its effect on self-image, which is an essential part of social relations. Conventional pharmacologic treatment based on antifungal agents is lengthy and expensive and has a high abandonment rate and a low cure rate. Therefore, a faster and more efficient solution has been sought using laser treatment. However, studies on the efficacy of this physical method are not conclusive due to the lack of uniformity in the method used to apply the laser and an objective method to measure the results. The aim of this study was to measure the efficacy of laser treatment of onychomycosis by microbiological cure and clinical evolution using the Onychomycosis Severity Index.
Methods: A prospective study with a strictly repetitive protocol of Nd:YAG 1,064-nm laser was applied to 50 participants with onychomycosis in the first toe, following the manufacturer's instructions. The efficacy of the treatment on fungal infection was measured by microbiological culture before and after treatment. The clinical evolution of the nail dystrophy was quantitatively evaluated using the Onychomycosis Severity Index.
Results: The efficacy of Nd:YAG 1,064-nm laser in eliminating fungal infection was 30% (15 participants). However, significant improvement in nail appearance (dystrophy) was observed in 100% of patients (P < .001).
Conclusions: Laser treatment has relatively low efficacy in treating fungal infection but results in an objective improvement in the clinical appearance of the nail in 100% of patients.
Several nonbiodegradable and biodegradable antibiotic cement delivery systems are available for the delivery of antibiotics for adjunctive therapy in the management of osteomyelitis. A major nonbiodegradable delivery system is polymethylmethacrylate beads. Antibiotics that can be incorporated into this delivery system are limited to the heat-stable antibiotics vancomycin and aminoglycosides, tobramycin being the most popular. Calcium sulfate and hydroxyapatite (Cerament Bone Void Filler) is a unique biocompatible and biodegradable ceramic bone void filler that can successfully deliver heat-stable and heat-unstable antibiotics in musculoskeletal infections. The use of Cerament as antibiotic beads has not been previously reported. An off-label case of diabetic foot osteomyelitis successfully managed with surgical bone resection and vancomycin Cerament antibiotic beads is presented. Subsequent surgery for the bone infection and staged removal of the antibiotic beads was not necessary. (J Am Podiatr Med Assoc 101(3): 259–264, 2011)
Linezolid-Associated Serotonin Syndrome
A Report of Two Cases
Linezolid, a mild monoamine oxidase inhibitor, is a commonly used antibiotic drug for the treatment of complicated skin and skin structure infections, including diabetic foot infections. Use of linezolid has been associated with serotonin syndrome, a potentially life-threatening condition typically caused by the combination of two or more medications with serotonergic properties, due to increased serotonin release. The goals of this article are to highlight the risk factors associated with the development of serotonin syndrome related to the use of linezolid and to aid in its prevention and early diagnosis. In this case series we report on two hospitalized patients who, while being treated with linezolid for pedal infections, developed serotonin syndrome. Both individuals were also undergoing treatment with at least one serotonergic agent for depression and had received this medication within 2 weeks of starting the antibiotic drug therapy. In these individuals, we noted agitation, confusion, tremors, and tachycardia within a few days of initiation of linezolid therapy. Owing to the risk of serotonin toxicity, care should be taken when prescribing linezolid in conjunction with any other serotonergic agent. Although serotonin syndrome is an infrequent complication, it can be potentially life threatening. Therefore, risks and benefits of therapy should be weighed before use.
Background: Verrucae are caused by infection of epidermal keratinocytes by human papilloma virus (HPV). Although there are currently more than 100 known types of HPV, certain lesions are consistently caused by infection with one or a few types. Recent studies have identified the presence of unusual HPV types in anogenital and cervical condylomata (warts) of patients infected with human immunodeficiency virus (HIV). Although cutaneous verrucae are typically caused by HPV-1, HPV-2, and HPV-4, infection with HIV may predispose an individual to infection with an unusual HPV type.
Methods: We report the detection of a rare HPV type in a clinically aggressive plantar verruca from an HIV-positive patient. The viral DNA from this specimen was analyzed to identify the predominant HPV type. To complete this analysis, HPV DNA was extracted from the formalin-fixed specimen, followed by polymerase chain reaction with consensus HPV primers and digestion with a specific group of restriction endonucleases. The fragments were separated on an agarose gel, and the restriction fragment length polymorphism pattern was compared with known patterns for identification of the specific HPV type.
Results: Identification of HPV-69, an HPV type previously reported to be rare and associated with dysplastic lesions, was confirmed by HPV DNA dot-blot hybridization with specific DNA probes for each known HPV type.
Conclusions: Plantar verrucae in HIV-positive patients may be associated with unusual HPV types and should be analyzed and treated aggressively given the potential for a more distinct clinical manifestation. Additional lesional analysis studies are needed. (J Am Podiatr Med Assoc 99(1): 8–12, 2009)
Background:
Split-thickness skin grafts can be used for foot wound closure in diabetic and nondiabetic patients. It is unknown whether this procedure is reliable for all diabetic patients, with or without comorbidities of diabetes, including cardiovascular disease, neuropathy, retinopathy, and nephropathy.
Methods:
We retrospectively reviewed 203 patients who underwent this procedure to determine significant differences in healing time, postoperative infection, and need for revisional surgery and to create a predictive model to identify diabetic patients who are likely to have a successful outcome.
Results:
Overall, compared with nondiabetic patients, diabetic patients experienced a significantly higher risk of delayed healing time and postoperative complication/infection and, hence, are more likely to require revisional surgery after undergoing the initial split-thickness skin graft procedure. These differences seemed to be related more to the presence of comorbidities than to diabetic status itself. Diabetic patients with preexisting comorbidities experienced a significantly increased risk of delayed healing time and postoperative infection and a higher need for revisional surgery compared with nondiabetic patients or diabetic patients without comorbidities. However, there were no significant differences in outcome between diabetic patients without comorbidities and nondiabetic patients.
Conclusions:
For individuals with diabetes but without exclusionary comorbidities, split-thickness skin grafting may be considered an effective surgical alternative to other prolonged treatment options currently used in this patient population. (J Am Podiatr Med Assoc 103(3): 223–232, 2013)
Background:
Onychomycosis and tinea pedis (athlete’s foot) are infections of the nails and skin caused by pathogenic fungi collectively known as dermatophytes. These infections are difficult to treat, and patients often relapse; it is thought that a patient’s footwear becomes infected with these fungal organisms and, thus, is an important reservoir for reinfection. Therefore, it is important to find an effective means for killing the dermatophytes that may have colonized the inner surface of the shoes of patients with superficial fungal infections. In this study, we developed an in vitro model for culturing dermatophytes in footwear and used this model to evaluate the effectiveness of a commercial ultraviolet shoe sanitizer in eradicating the fungal elements residing in shoes.
Methods:
Leather and athletic shoes (24 pairs) were inoculated with either Trichophyton rubrum or Trichophyton mentagrophytes (107 colony-forming units/mL) strains and were placed at 35°C for 4 to 5 days. Next, we compared the ability of swabbing versus scraping to collect microorganisms from infected shoes. Following the optimized method, shoes were infected and were irradiated with one to three cycles of radiation. The inner surfaces of the shoes were swabbed or scraped, and the specimens were cultured for dermatophyte colony-forming units.
Results:
Leather and canvas shoes were infected to the same extent. Moreover, scraping with a scalpel was overall more effective than was swabbing with a cotton-tipped applicator in recovering viable fungal elements. Irradiation of shoes with one, two, or three cycles resulted in reduction of fungal colonization to the same extent.
Conclusions:
The developed infected shoe model is useful for assessing the effectiveness of ultraviolet shoe sanitizers. Also, ultraviolet treatment of shoes with a commercial ultraviolet C sanitizing device was effective in reducing the fungal burden in shoes. These findings have implications regarding breaking foot infection cycles. (J Am Podiatr Med Assoc 102(4): 309–313, 2012)
Fluoroquinolones have been associated with tendinopathies. The authors present three cases of Achilles tendinopathy in which the patients’ symptoms were preceded by treatment for unrelated bacterial infections with ciprofloxacin. Although the exact mechanism of the relationship is not understood, those who engage in sports or exercise should be advised of the risk of quinolone-induced tendinopathy. (J Am Podiatr Med Assoc 93(4): 333-335, 2003)
