How long to treat with antibiotics following amputation in patients with diabetic foot infections? Are the 2012 IDSA DFI guidelines reasonable?

WHAT IS KNOWN AND OBJECTIVE: To the best of our knowledge, there has been no published study designed to identify the most appropriate duration of antibiotic therapy in lower extremity skin and skin structure infections in diabetic patients [aka "diabetic foot infections" (DFI)] post-amputation. However, recent guidelines published by the Infectious Diseases Society of America (IDSA) provide recommendations for treatment duration in these patients. Therefore, our objective is to review the literature evaluating antibiotic treatment in DFI to determine if the IDSA guidelines are reasonable. COMMENT: Evidence for the use of antibiotics after amputation comes largely from perioperative surgical prophylaxis studies evaluating the rate of infection after amputation. Three such studies were identified; 2 found a 5-day course of antibiotics post-amputation resulted in a reduction of infection rate, while 1 found no additional benefit. Comparative antibiotic studies in DFI also offers evidence for treatment duration, of which, 10 studies were identified. Five included patients who received amputations; however, only 1 reported treatment outcomes in a subset of diabetics requiring amputation. In this study, the authors concluded that antibiotic treatment is likely necessary after amputation. WHAT IS NEW AND CONCLUSION: Given the general lack of data, we recommend that post-operative treatment duration be individualized, and, until further studies are done, it seems reasonable to adhere to the recommendation provided by the 2012 IDSA DFI guidelines for a 2-5 day course of antibiotic therapy post-operatively when no residual infected tissue remains.

Application of antimicrobial stewardship to optimise management of community acquired pneumonia.

The aim of this study was to review the application of antimicrobial stewardship principles to the management of community-acquired pneumonia (CAP). Data from 14 published clinical studies, meta-analyses and practice guidelines regarding the application of antimicrobial stewardship strategies to the management of CAP were identified and analysed. In the context of CAP, application of stewardship strategies (alone or in combination) has been shown to increase physician awareness of guidelines, improve appropriate antimicrobial use and reduce unnecessary antimicrobial prescribing. In addition, application has had a profound favourable impact on patient outcomes, including decreased 30-day mortality and in-hospital mortality rates, reduced length of hospital stay, reduced treatment failure rates and reduced healthcare costs. Antimicrobial stewardship programmes have been demonstrated to successfully increase the level of appropriate antibiotic prescribing, reduce pathogen resistance and improve clinical outcomes in the management of CAP within hospitals. Studies have also shown that adherence to evidence-based guidelines, even at the level of the individual clinician, can have a profound and positive impact on patient outcomes and healthcare costs. Adherence to evidence-based guidelines can have a profound and positive impact on patient outcomes and healthcare costs.

Tigecycline: a new glycylcycline antimicrobial.

Tigecycline is a new glycyclcycline antimicrobial recently approved for use in the USA, Europe and elsewhere. While related to the tetracyclines, tigecycline overcomes many of the mechanisms responsible for resistance to this class. It demonstrates favourable in vitro potency against a variety of aerobic and anaerobic Gram-positive and Gram-negative pathogens, including those frequently demonstrating resistance to multiple classes of antimicrobials. This includes methicillin-resistant Staphylococcus aureus, penicillin-resistant S. pneumoniae, vancomycin-resistant enterococci, Acinetobacter baumannii, beta-lactamase producing strains of Haemophilis influenzae and Moraxella catarrhalis, and extended-spectrum beta-lactamase producing strains of Escherichia coli and Klebsiella pneumoniae. In contrast, minimum inhibitory concentrations for Pseudomonas and Proteus spp. are markedly elevated. Tigecycline is administered parenterally twice daily. Randomised, controlled trials have demonstrated that tigecycline is non-inferior to the comparators for the treatment of complicated skin and skin structure infections, as well as complicated intra-abdominal infections. The most frequent and problematic side effect associated with its administration to date has been nausea and/or vomiting.

Safety of aerosolized amphotericin B lipid complex in lung transplant recipients.

BACKGROUND: Fungal infections remain an important cause of morbidity and mortality in lung transplant recipients. Aerosolized amphotericin B lipid complex (ABLC) may be more efficacious than conventional amphotericin B in the prevention of fungal infections in animal models, but experience with aerosolized ABLC in humans is lacking. METHODS: We conducted a prospective, noncomparative study designed to evaluate safety of aerosolized ABLC in lung or heart-lung transplant recipients. RESULTS: A total of 381 treatments were administered to 51 patients. Complete spirometry records were available for 335 treatments (69 in intubated patients, 266 in extubated patients). ABLC was subjectively well tolerated in 98% of patients. Pulmonary mechanics worsened by 20% or more posttreatment in less than 5% of all treatments. There were no significant adverse events related to study medication in any patient, and 1-year survival for all enrolled patients was 78%. CONCLUSION: Administration of nebulized ABLC is safe in the short-term and well-tolerated in lung transplant recipients. Additional prospective, randomized studies are needed to determine the efficacy of aerosolized ABLC alone or in conjunction with systemic therapies in the prevention of fungal infections in lung transplant recipients.

Treatment of methicillin-resistant staphylococcus aureus infections with quinupristin-dalfopristin in patients intolerant of or failing prior therapy. For the Synercid Emergency-Use Study Group.

Safety and efficacy of quinupristin-dalfopristin (an injectable streptogramin antibiotic) were evaluated in the treatment of a variety of infections due to methicillin-resistant Staphylococcus aureus (MRSA) in patients either intolerant of or failing prior therapy. The influence of resistance phenotypes on treatment outcome was also assessed. This worldwide, multicentre, open-label, non-comparative, emergency-use clinical study enrolled patients with one or more of nine predefined, culture-confirmed infections with MRSA, who had no clinically appropriate alternative antibiotic therapy. The recommended quinupristin-dalfopristin dose was 7.5 mg/kg administered iv every 8 h for a duration judged appropriate by the investigator. There were no restrictions on prior or concomitant treatment with other antibiotics. Clinical, microbiological and laboratory assessments were performed at baseline, during study drug treatment, within 24 h after the last dose, and 7-21 days post-therapy. Ninety patients [age (mean +/- S.D.) 57.4 +/- 18.5 years] with significant underlying medical illnesses were treated at 63 centres in five countries. The most common indications were bone and joint infection (44.4% of patients) and skin and skin structure infection (16.7%). The mean (+/- S.D.) daily dose and treatment duration was 20.2 +/- 2.9 mg/kg/day for 28.5 +/- 22.3 days, most frequently administered every 8 h. The overall success rate (defined as a clinical outcome of either cure or improvement and a bacteriological outcome of eradication or presumed eradication) was 71.1% in the all-treated population (n = 90) and 66.7% in patients who were both clinically and bacteriologically evaluable (n = 27). Success rates for endocarditis, respiratory tract infection and bacteraemia of unknown source were below the population mean. The macrolide-lincosamide-streptogramin type B resistance phenotype did not appear to alter the response rate. The most common non-venous adverse events related to study medication were arthralgias (10.8%), myalgias (8.6%) and nausea (8.6%). Quinupristin-dalfopristin should be considered as a treatment option for infections caused by MRSA, especially in patients intolerant of or failing alternate therapy.

Antifungal pharmacodynamics: review of the literature and clinical applications.

Invasive fungal infections are seen with growing frequency, likely due to increases in numbers of patients at risk of infection. Optimal selection and dosing of antifungal agents are important, as these infections are often refractory to available therapy. In contrast to antibacterials, studies examining the pharmacodynamic properties of antifungals and their application in treating invasive disease often are lacking. Agents administered for invasive infections are amphotericin B, flucytosine, and azole antifungals. Several drugs are under investigation, such as posiconazole, voriconazole, and the echinocandins, and preliminary pharmacodynamic data likely will help shape dosing regimens. Clinical trials that investigated dosage and administration, as well as the potential benefits of combination and sequential therapy, are addressed. In addition, antifungal susceptibility and animal models of infection are discussed.

Agents for treatment of invasive fungal infections.

The incidence of fungal infections continues to rise as the population of immunocompromised individuals increases. Despite the enlarging numbers of infections, there are only a few antifungal agents for treatment of deep-seated, invasive infections. These agents include amphotericin B, flucytosine, terbinafine, and several azoles. Progress has been made in understanding the role of these agents in a variety of infections and this article examines in detail these agents and their prophylactic, empiric, and therapeutic uses in invasive mycoses. This article focuses on general concepts of antifungal therapies and provides a detailed review of each antifungal agent available for treatment of deep-seated mycoses.

Ceftriaxone once daily for four weeks compared with ceftriaxone plus gentamicin once daily for two weeks for treatment of endocarditis due to penicillin-susceptible streptococci. Endocarditis Treatment Consortium Group.

This randomized, multicenter, open-label study compared the efficacy and safety of monotherapy with 2 g of intravenous ceftriaxone once daily for 4 weeks with those of combination therapy with 2 g of intravenous ceftriaxone and 3 mg of intravenous gentamicin/kg once daily for 2 weeks as therapy for endocarditis due to penicillin-susceptible streptococci. Sixty-one patients were enrolled in the study. Clinical cure was observed for 51 evaluable patients both at termination of therapy and at the 3-month follow-up: 25 (96.2%) of 26 monotherapy recipients and 24 (96%) of 25 combination therapy recipients. Of the 23 patients in each treatment group who were microbiologically evaluable, 22 (95.7%) in each group were considered cured. No patient had evidence of relapse. Fourteen patients (27.5%) required cardiac surgery after initiation of treatment, including five monotherapy recipients and nine combination therapy recipients. Adverse effects were minimal in both treatment groups. We conclude that 2 g of ceftriaxone once daily for 4 weeks and 2 g of ceftriaxone in combination with 3 mg of gentamicin/kg once daily for 2 weeks are both effective and safe for the treatment of streptococcal endocarditis.

Programs promoting timely sequential antimicrobial therapy: an American perspective.

Interventional programs promoting the timely conversion of intravenous to oral antimicrobial therapy have been reported from several hospitals in the U.S.A. and elsewhere. Factors influencing the initiation and conduct of these programs include technological advances, changes in health care delivery or reimbursement, publication of supportive clinical data and growth of clinical pharmacy services. Successful programs employ comprehensive, multidisciplinary strategies to contain antimicrobial-related expenditures using interventions based on structured criteria. Future emphasis on cost-effective drug therapy, advances in computer-based information technology and development of care maps can have favourable influences on the growth of these programs in the U.S.A.

Chest discomfort associated with liposomal amphotericin B: report of three cases and review of the literature.

Liposomal formulations of amphotericin B are designed to maintain therapeutic efficacy of amphotericin B deoxycholate while reducing its associated toxicities. In three patients chest discomfort occurred during planned 1-hour infusions of liposomal amphotericin B (AmBisome) 3 mg/kg/day during an open-label trial. The first patient experienced chest tightness and difficulty breathing and the second had dyspnea and acute hypoxia, both within 10 minutes of the start of the infusion. The third patient complained of chest pain 5 minutes after the start of two infusions. All symptoms resolved on terminating therapy. Two patients were later rechallenged with slower infusions and tolerated the drug well. A review of the English-language literature revealed only two other case reports of infusion-related chest or pulmonary reactions with the drug, although similar reactions were noted in several reports of clinical trials. Further review of the literature revealed reports of chest and pulmonary adverse events with other liposomal formulations of amphotericin B, liposomal daunorubicin, liposomal doxorubicin, and liposomes. The pathophysiology of such reactions remains unclear, and premedication with diphenhydramine did not completely prevent this reaction in one of our patients. We recommend infusing liposomal amphotericin B over at least 2 hours with careful monitoring for adverse reactions.

A prospective, open-label study of single-dose ciprofloxacin absorption after chemotherapy in patients with malignancy.

The absorption of a single oral dose of ciprofloxacin 750 mg in patients with cancer who had chemotherapy-induced Cancer and Leukemia Group B grade I or II mucositis was evaluated. Ciprofloxacin was administered after an overnight fast. Plasma samples were collected before and 0.5, 1, 1.5, 2, 3, 4, 6, 8, and 12 hours after the dose. Drug concentrations were determined by reverse-phase high-performance liquid chromatography with fluorescence detection. Pharmacokinetic values were characterized by noncompartmental methods. The mean +/- SD for area under the curve, mean peak concentration (C(max)), and time to C(max) (T(max)) were 18.7 +/- 5.03 mg/L x hour, 4.41 +/- 1.74 mg/L, and 1.81 +/- 0.843 hours, respectively. The absorption of oral ciprofloxacin in patients with chemotherapy-induced grade I or II mucositis compares with that in healthy volunteers. These findings may call for further pharmacokinetic evaluation of the drug in a similar patient population.

Treatment of vancomycin-resistant enterococci, with a focus on quinupristin-dalfopristin.

Enterococci are the second most common cause of hospital-acquired infections, and drug resistance among these organisms is a growing problem. Vancomycin-resistant enterococci (VRE) now account for 7.9% of the nosocomial enterococcal infections. There is no standard therapy for VRE. Although some agents have shown in vitro activity alone or in combination, including ciprofloxacin, doxycycline, novobiocin, teicoplanin, chloramphenicol, and rifampin, treatment options are limited to combinations of drugs with marginal efficacy against the pathogens. Quinupristin-dalfopristin is a new investigational agent with activity against gram-positive cocci, including VRE.

Effect of simultaneous didanosine administration on itraconazole absorption in healthy volunteers.

STUDY OBJECTIVE: To investigate the effect of simultaneously administered didanosine (ddI) on the absorption of a single dose of itraconazole. DESIGN: Randomized, crossover, unblinded single-dose pharmacokinetic study in healthy volunteers. Comparisons of itraconazole alone and itraconazole with simultaneous ddI were performed on days 1 and 15. SETTING: A university medical center. PATIENTS: Seven healthy men and women. Six subjects (86%) completed the study; one was removed due to the development of a rash. INTERVENTIONS: Volunteers received a single 200-mg oral dose of itraconazole or itraconazole with concomitant oral ddI 300 mg (two 150-mg tablets) dispersed in 240 ml water. Each regimen was separated by a 2-week washout period. Serum samples were obtained frequently for 12 hours after the dose. MEASUREMENTS AND MAIN RESULTS: Concentrations of itraconazole were determined using a microbiologic assay. Individual concentrations in serum versus time data were evaluated by linear regression analysis. Peak serum concentration and time to peak were determined by visual inspection of each individual's serum concentration-time curve. A mean +/- SD peak serum itraconazole concentration of 0.90 +/- 0.30 micrograms/ml was observed at 3.0 +/- 0.7 hours when itraconazole was administered alone, compared with undetectable levels in all patients during therapy with ddI. CONCLUSIONS: Simultaneous oral administration of ddI significantly decreases absorption of itraconazole. These drugs should not be administered concurrently.

Pharmacotherapy of disseminated histoplasmosis in patients with AIDS.

OBJECTIVE: To review the pharmacotherapy of disseminated histoplasmosis (DH) in patients with AIDS. The article provides an overview of the pathophysiology, epidemiology, clinical presentation and diagnosis of this disease. Clinical trials reporting intervention with antifungal therapy are reviewed, with an emphasis on efficacy and toxicity of these agents. DATA SOURCES: A MEDLINE search from 1976 to the present was performed to identify pertinent biomedical literature, including reviews. STUDY SELECTION: All available reviews and clinical trials in AIDS patients were evaluated, as were all available case series and interventional clinical trials. DATA SYNTHESIS: DH in patients with HIV infection is an AIDS-defining opportunistic infection caused by Histoplasma capsulatum. It is most frequently observed in HIV-infected patients living in or traveling to endemic regions. The clinical presentation most often includes fever and weight loss, but may be complicated by comorbid illness such as other opportunistic infections. Diagnosis is best established by histologic examination of peripheral blood smear or bone marrow aspirate, or isolation of the organism in cultures of blood, bone marrow, and respiratory secretions. Serologic examinations may provide supportive diagnostic information. Detection of histoplasma polysaccharide antigen (HPA) in serum or urine may prove to be a promising approach for the rapid diagnosis and therapeutic monitoring of DH in AIDS patients. In contrast to immunocompetent hosts, high relapse rates are reported after therapy in AIDS patients. Therefore, initial (induction) therapy is routinely followed by long-term (maintenance) therapy to prevent relapse. Issues regarding the selection, dosage, and duration of therapy, as well as prophylaxis of patients at highest risk, still need to be addressed by controlled clinical trials. CONCLUSIONS: Amphotericin B is presently the drug of choice for induction therapy. Maintenance therapy with either amphotericin B or an oral azole antifungal agent active against H. capsulatum is necessary to prevent relapse. Itraconazole, a triazole antifungal agent, may provide effective alternative therapy for both induction and maintenance treatment of DH.

Adverse drug reactions to systemic antifungals. Prevention and management.

Systemic administration of antifungal agents for invasive mycoses has dramatically increased over the past 10 years in many fields of medicine. The increase has been due both to an increasing immune compromised population and to potent antibacterial agents which allow these fungi to invade tissue. It is apparent that our understanding of the use of both the old and new antifungal agents has significantly increased in the last few years. In this review, we attempt to document our extensive knowledge of the adverse effects of the polyenes, flucytosine, griseofulvin and azoles when given systemically for treatment. Interwoven in this documentation of the adverse reactions to these agents is the attempt to help clinicians potentially avoid some of these adverse effects and if they do occur, to be able to identify and successfully manage them.

Azithromycin--spectrum of activity, pharmacokinetics, and clinical applications.

Azithromycin is an azalide antimicrobial agent. Structurally related to the macrolide antibiotic erythromycin, its mechanism of activity (similar to erythromycin) is interference with bacterial protein synthesis by binding to the 50S component of the 70S ribosomal subunit. Although slightly less potent than erythromycin against gram-positive organisms, azithromycin demonstrates superior activity in vitro against a wide variety of gram-negative bacilli, including Haemophilus influenzae. Absorption is approximately 37% after a 500-mg oral dose. The large volume of distribution (23 L/kg) and low peak serum level (0.4 micrograms/ml) are consistent with data demonstrating extensive tissue distribution and intracellular accumulation. Metabolism is predominantly hepatic (to inactive metabolites), with biliary excretion a major pathway of elimination. Drug elimination is biphasic, with a terminal half-life of up to 5 days. Published trials have examined the efficacy and safety of azithromycin in the treatment of adults with upper and lower respiratory tract infections, skin and skin structure infections, streptococcal pharyngitis, and sexually transmitted diseases. Many used a 5-day course of 250 mg once daily, supplemented with a 250-mg dose on the first day of therapy. Selected trials in sexually transmitted diseases examined single 1-g doses. Promising results also were obtained with oral daily doses of 500 mg in patients with human immunoviral infection who also had Mycobacterium avium complex infection and in animals with toxoplasmosis. Adverse reactions are primarily gastrointestinal (nausea, diarrhea, abdominal pain), with minimal laboratory abnormalities reported. Gastrointestinal tolerance is better than that of erythromycin. Drug interactions have not been observed to date, although coadministration of azithromycin with a large meal may reduce absorption by up to 50%.

Amphotericin B: 30 years of clinical experience.

Amphotericin B, the first commercially significant antifungal drug, has been available for more than 30 years. This polyene macrolide antifungal agent continues to play a major role in the treatment of systemic fungal infections, despite the introduction of newer agents such as the azoles. Given the proved efficacy of amphotericin B--and the increasing number of indications for antifungal agents--an extensive review of this drug is warranted. This paper discusses the clinical uses of amphotericin B, including its application in AIDS-related fungal infections, in neutropenic cancer patients who are persistently febrile, and in infections of the central nervous system, lung, peritoneum, genitourinary system, eye, and skin. The paper also reviews the drug's adverse reactions, with a discussion of administration techniques that may reduce these reactions, and its spectrum of activity, pharmacokinetics, and dosage and administration.

Comparison of the safety and efficacy of intravenous ciprofloxacin and intravenous ceftazidime in the treatment of selected infections.

A study was conducted to determine the comparative safety and efficacy of intravenous ciprofloxacin with that of intravenous ceftazidime in the treatment of selected infections. Male and female inpatients 18 years or older had bacterial infections of the blood, skin or skin/structure, intra-abdominal region, lower respiratory tract, or urinary tract (considered complicated) caused by organisms susceptible to both ciprofloxacin and ceftazidime. Patients were randomly assigned to receive either ciprofloxacin 200 mg intravenously every 12 hours or ceftazidime 0.5 to 2 g intravenously every eight to 12 hours. Clinical evaluations were performed daily during therapy and within five to nine days after therapy was complete. For patients with urinary tract infection, urine for culture was obtained during (Day 3 or 4) and after (five to nine days and three to five weeks) therapy. A total of 86 patients were enrolled into the study. Forty-three received ciprofloxacin and 43 received ceftazidime. There were 22 evaluable patients in the ciprofloxacin group with 24 infection sites: skin/skin structure (eight), respiratory tract (nine), blood (two), urinary tract (five). In the ceftazidime group, there were 26 evaluable patients with 29 infection sites: skin/skin structure (15), respiratory tract (nine), blood (three), and urinary tract (two). The mean duration of therapy with ciprofloxacin and ceftazidime was 7.5 days (range, four to 28 days) and 8.4 days (range, three to 25 days), respectively. Bacteriologic eradication of the causative organisms occurred at 17 infection sites (70.8 percent) in the ciprofloxacin-treated patients and 21 infection sites (72.4 percent) in the ceftazidime group. Clinically, resolution or improvement in signs/symptoms was demonstrated in 22 patients (91.7 percent) in the ciprofloxacin group and 26 patients (89.7 percent) in the ceftazidime group. Bacteriologic response (by organism) and overall response were comparable in both groups. All enrolled patients were evaluated for determination of safety. Adverse events considered possibly or probably related to the study drugs were reported in 16 of 43 patients (37.2 percent) in the ciprofloxacin group and four of 43 patients (9.3 percent) in the ceftazidime group. Ciprofloxacin and ceftazidime were equally efficacious in the treatment of selected infections, but ciprofloxacin was associated with a higher incidence of adverse reactions probably or possibly related to drug administration. Further studies with larger sample sizes in selected patient populations will be required to identify differences in efficacy among the two antibiotics.

Bioequivalence assessment of zidovudine (Retrovir) syrup, solution, and capsule formulations in patients infected with human immunodeficiency virus.

The objectives of this open-labeled, multiple-dose, three-way-crossover trial were to evaluate the safety and tolerance of zidovudine (Retrovir) oral syrup and to assess the bioequivalence of this formulation relative to zidovudine solution and capsule formulations in human immunodeficiency virus-infected patients. Over the 7-day study, 12 adult male subjects received 12 administrations each of the capsule, solution, and syrup formulations every 4 h (six times daily) in a randomized sequence. Frequent blood samples were collected over the 4-h period after dose 12 was administered. Zidovudine concentrations in plasma were determined by a specific and sensitive radioimmunoassay. Results from statistical analyses indicated that all three formulations were bioequivalent with respect to systemic availability (area under the time-concentration curve) and that the syrup was also equivalent to the solution with respect to the maximum peak concentration in serum. The lower relative maximum peak concentration in serum (approximately 81%) and small delays in time to peak concentration (less than 30 min) of the capsule formulation as compared with the liquid formulations are thought to be due to the additional processes of disintegration and dissolution associated with capsule administration. All three preparations were well tolerated during the 7-day study.