Motile Aeromonas infections of the foot are caused mostly by post-traumatic incidence, occurring mostly during summer months. Serious complications such as osteomyelitis and amputation can result if the infections go untreated or are inadequately treated. The role of each species of motile Aeromonas in pathogenesis and response to antimicrobial agents is not well understood because of taxonomic uncertainty. As a group, motile Aeromonas respond well to aminoglycosides, second-generation and third-generation cephalosporins, quinolones, and some beta-lactam antibiotics.
The vast majority of patients with human immunodeficiency virus (HIV) and acquired immune deficiency syndrome (AIDS) have symptoms or signs involving the feet and lower extremities. Patients presenting to podiatrists with foot complaints may, in fact, have neurologic complications of HIV originating in any level of the neuraxis, and multiple levels may be involved. These include multiple classes of peripheral neuropathy and myopathy, inflammatory radiculopathy, myelopathy, and central nervous system lesions caused by direct HIV infection or opportunistic infections. Common complaints such as pain, numbness, burning, tingling, weakness, cramps, unsteady gait, and others should be systematically evaluated with both podiatric and neurologic etiologies in mind for early diagnosis and intervention.
By following a systematic approach to the patient history, physical examination, and laboratory analysis in cases of infections, rapid and accurate therapeutic intervention becomes possible. This action can prevent possibly devastating infectious complications, ranging from partial amputation to death. The current litigious climate dictates thorough evaluation and documentation of all infectious diseases of the lower extremity.
Objective: To investigate the predictive value of erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) in persons with and without diabetes with osteomyelitis (OM).
Methods: We evaluated 455 patients in a retrospective cohort study of patients admitted to the hospital with diabetic foot OM (n = 177), diabetic foot soft-tissue infections (STIs) (n = 176), nondiabetic OM (n = 51), and nondiabetic STIs (n = 51). Infection diagnosis was determined through bone culture, histopathologic examination for OM, and/or imaging (magnetic resonance imaging/single-photon emission computed tomography) for STI. The optimal cutoff values of ESR and CRP in predicting OM were determined by receiver operating characteristic curve analysis. Sensitivity, specificity, positive and negative predictive values, and positive and negative likelihood ratios were determined through contingency tables.
Results: In persons without diabetes with STI or OM, the mean ESR and CRP differences were 10.0 mm/h and 2.6 mg/dL, respectively. In contrast, persons with diabetes had higher levels of each: 24.8 mm/h and 6.8 mg/dL, respectively. As a result, ESR and CRP predicted OM better in patients with diabetes. However, when patients were stratified by neuropathy status, ESR remained predictive of OM in diabetic patients with neuropathy (75% sensitivity, 58% specificity) but not in diabetic patients without neuropathy (50% sensitivity, 44% specificity). Also, CRP remained predictive irrespective of neuropathy status. A similar trend was observed in patients without diabetes.
Conclusions: Previous studies have reported that ESR and CRP are predictive of OM. However, this study suggests that neuropathy influences the predictive value of inflammatory biomarkers. The underlying mechanisms require further study.
Topical Application of a Gentamicin-Collagen Sponge Combined with Systemic Antibiotic Therapy for the Treatment of Diabetic Foot Infections of Moderate Severity
A Randomized, Controlled, Multicenter Clinical Trial
The aim of this pilot study was to determine the safety and potential benefit of adding a topical gentamicin-collagen sponge to standard of care (systemic antibiotic therapy plus standard diabetic wound management) for treating diabetic foot infections of moderate severity.
We randomized 56 patients with moderately infected diabetic foot ulcers in a 2:1 ratio to receive standard of care plus the gentamicin-collagen sponge (treatment group, n = 38) or standard of care only (control group, n = 18) for up to 28 days of treatment. Investigators performed clinical, microbiological, and safety assessments at regularly scheduled intervals and collected pharmacokinetic samples from patients treated with the gentamicin-collagen sponge. Test of cure was clinically assessed 14 days after all antibiotic therapy was stopped.
On treatment day 7, we noted clinical cure in no treatment patients and three control patients (P = .017). However, for evaluable patients at the test-of-cure visit, the treatment group had a significantly higher proportion of patients with clinical cure than did the control group (22 of 22 [100.0%] versus 7 of 10 [70.0%]; P =.024). Patients in the treatment group also had a higher rate of eradication of baseline pathogens at all visits (P ≤ .038) and a reduced time to pathogen eradication (P < .001). Safety data were similar for both groups.
Topical application of the gentamicin-collagen sponge seems safe and may improve clinical and microbiological outcomes of diabetic foot infections of moderate severity when combined with standard of care. These pilot data suggest that a larger trial of this treatment is warranted. (J Am Podiatr Med Assoc 102(3): 223-232, 2012)
Peripheral skeletal infections caused by Mycobacterium are widely reported in the literature. Unfamiliarity with this disease, or oversight caused by inexperience may result in failure to thoroughly investigate the presence of this organism. An unusual case of tuberculous osteomyelitis involving the second digit of the foot is presented. The authors emphasize the importance of including cultures of acid-fast bacillus in the work-up of atypical infectious processes of the foot and ankle, and include Mycobacterium in their differential until it is positively ruled out. An in-depth radiologic review is included.
With the discovery of human immunodeficiency virus (HIV), researchers identified the etiologic agent for acquired immunodeficiency syndrome (AIDS). Although neither a cure nor a vaccine exists for this fatal disease, considerable information is now available on the progression from HIV infection through AIDS. Understanding the natural history of this progression can facilitate early detection and intervention. Although the epidemic continues to claim lives at an accelerating rate, the timely administration of prophylactic and therapeutic modalities can significantly prolong survival time for many patients. As more effective and less toxic treatments are developed, it will become increasingly crucial for practitioners to accurately diagnose and stage HIV-infected patients.
Chromoblastomycosis is a cutaneous-subcutaneous fungal infection that is being seen more frequently in patients living in the US. The disease normally occurs in patients living in tropical and subtropical regions, but as the number of immigrants into the US increases, podiatrists must be able to recognize the manifestations of chromoblastomycosis. The most common sight involved is the lower extremity where it easily can be confused with other diseases such as tertiary syphilis, phaeohyphomycosis, and cutaneous tuberculosis, among others. Small lesions should be excised, while antifungal drugs, such as itraconazole, should be used when more tissue is involved.
Twenty-seven pedal soft tissue and bone infections in 26 patients were treated with surgical necrectomy of infected tissues and implantation of antibiotic-loaded polymethyl methacrylate bone cement beads on chains. The definitive diagnosis of the infected tissues was obtained by culture and histologic examination in all of the cases. A wide variety of foot infections was successfully treated in this manner. The success rate without recurrence of osteomyelitis or soft tissue infection was 95% in this study at an average of 16 months after surgery.
This retrospective study reviewed the culture results of 112 admissions to a multidisciplinary diabetic foot care team with a primary diagnosis of infected diabetic pedal ulceration. An average of 1.5 +/- 0.9 species per patient (P < 0.0001) were isolated. Eighty-nine percent of wounds cultured grew two or fewer organisms. Anaerobic species were isolated in only 5% of all cultures. Of these isolates, the distinction between anaerobic colonization and true anaerobic infection is made. Results suggest that aggressive early hospitalization, coupled with aggressive intraoperative debridement, may yield less microbiologically complex infections that may be controlled with less expensive narrow spectrum antibiotic therapy. Diagnosis of the infected pedal ulceration of a patient with diabetes is a clinical one. If this diagnosis is combined with appropriate surgical intervention, microbiologic correlation, and antimicrobial therapy, the result may be a less complex hospital course and improved outcome.