Topical antimicrobial peptide omiganan recovers cutaneous dysbiosis but does not improve clinical symptoms in patients with mild to moderate atopic dermatitis in a phase 2 randomized controlled trial.

BACKGROUND: Dysbiosis and colonization with Staphylococcus aureus is considered to play an important role in the pathogenesis of atopic dermatitis (AD). Recovering this dysbiosis may improve AD symptoms. Omiganan is a synthetic indolicidin analogue antimicrobial peptide with activity against S aureus and could be a viable new treatment option for AD. OBJECTIVE: To explore the tolerability, clinical efficacy, and pharmacodynamics of omiganan in mild to moderate AD. METHODS: Eighty patients were randomized to omiganan 1%, 1.75%, or 2.5% or vehicle twice daily for 28 days on all lesions. Weekly visits included clinical scores and microbiological and pharmacodynamic assessments of 1 target lesion. RESULTS: In all omiganan treatment groups, dysbiosis was recovered by reducing Staphylococcus species abundance and increasing diversity. A reduction of cultured S aureus was observed in all omiganan treatment groups, with a significant reduction for omiganan 2.5% compared to vehicle (-93.5%; 95% CI, -99.2 to -28.5%; P = .02). No significant clinical improvement was observed. CONCLUSION: Topical administration of omiganan twice daily for up to 28 days in patients with mild to moderate AD led to a recovery of dysbiosis but without clinical improvement. Therefore, a monotreatment that selectively targets the microbiome does not appear to be a successful treatment strategy in mild to moderate AD.

Risk factors for fluoroquinolone-resistant Escherichia coli in adults with community-onset febrile urinary tract infection.

OBJECTIVES: To assess risk factors for fluoroquinolone resistance in community-onset febrile Escherichia coli urinary tract infection (UTI). METHODS: A nested case-control study within a cohort of consecutive adults with febrile UTI presenting at primary healthcare centres or emergency departments during January 2004 through December 2009. Resistance was defined using EUCAST criteria (ciprofloxacin MIC >1.0 mg/L). Cases were subjects with fluoroquinolone-resistant E. coli, and controls those with fluoroquinolone-susceptible isolates. Multivariable logistic regression analysis was used to identify potential risk factors for fluoroquinolone resistance. RESULTS: Of 787 consecutive patients, 420 had E. coli-positive urine cultures. Of these, 51 (12%) were fluoroquinolone resistant. Independent risk factors for fluoroquinolone resistance were urinary catheter [odds ratio (OR) 3.1; 95% confidence interval (CI) 0.9-11.6], recent hospitalization (OR 2.0; 95% CI 1.0-4.3) and fluoroquinolone use in the past 6 months (OR 17.5; 95% CI 6.0-50.7). Environmental factors (e.g. contact with animals or hospitalized household members) were not associated with fluoroquinolone resistance. Of fluoroquinolone-resistant strains, 33% were resistant to amoxicillin/clavulanate and 65% to trimethoprim/sulfamethoxazole; 14% were extended-spectrum ß-lactamase (ESBL) positive compared with <1% of fluoroquinolone-susceptible isolates. CONCLUSIONS: Recent hospitalization, urinary catheter and fluoroquinolone use in the past 6 months were independent risk factors for fluoroquinolone resistance in community-onset febrile E. coli UTI. Contact with animals or hospitalized household members was not associated with fluoroquinolone resistance. Fluoroquinolone resistance may be a marker of broader resistance, including ESBL positivity.

Procalcitonin reflects bacteremia and bacterial load in urosepsis syndrome: a prospective observational study.

INTRODUCTION: Guidelines recommend that two blood cultures be performed in patients with febrile urinary tract infection (UTI), to detect bacteremia and help diagnose urosepsis. The usefulness and cost-effectiveness of this practice have been criticized. This study aimed to evaluate clinical characteristics and the biomarker procalcitonin (PCT) as an aid in predicting bacteremia. METHODS: A prospective observational multicenter cohort study included consecutive adults with febrile UTI in 35 primary care units and 8 emergency departments of 7 regional hospitals. Clinical and microbiological data were collected and PCT and time to positivity (TTP) of blood culture were measured. RESULTS: Of 581 evaluable patients, 136 (23%) had bacteremia. The median age was 66 years (interquartile range 46 to 78 years) and 219 (38%) were male. We evaluated three different models: a clinical model including seven bed-side characteristics, the clinical model plus PCT, and a PCT only model. The diagnostic abilities of these models as reflected by area under the curve of the receiver operating characteristic were 0.71 (95% confidence interval (CI): 0.66 to 0.76), 0.79 (95% CI: 0.75 to 0.83) and 0.73 (95% CI: 0.68 to 0.77) respectively. Calculating corresponding sensitivity and specificity for the presence of bacteremia after each step of adding a significant predictor in the model yielded that the PCT > 0.25 µg/l only model had the best diagnostic performance (sensitivity 0.95; 95% CI: 0.89 to 0.98, specificity 0.50; 95% CI: 0.46 to 0.55). Using PCT as a single decision tool, this would result in 40% fewer blood cultures being taken, while still identifying 94 to 99% of patients with bacteremia.The TTP of E. coli positive blood cultures was linearly correlated with the PCT log value; the higher the PCT the shorter the TTP (R(2) = 0.278, P = 0.007). CONCLUSIONS: PCT accurately predicts the presence of bacteremia and bacterial load in patients with febrile UTI. This may be a helpful biomarker to limit use of blood culture resources.

Risk factors for bacteremia with uropathogen not cultured from urine in adults with febrile urinary tract infection.

In a prospective study involving 642 patients with febrile urinary tract infection (UTI), we found antimicrobial pretreatment (odds ratio [OR], 3.3), an indwelling urinary catheter (OR, 2.8), and malignancy (OR, 2.7) to be independent risk factors for bacteremia with a uropathogen that was not cultured or recognized in the urine. Although the diagnostic value of blood cultures has been questioned in UTI, we advocate performing blood cultures for patients with these risk factors.

Aerosolized liposomal amphotericin B for the prevention of invasive pulmonary aspergillosis during prolonged neutropenia: a randomized, placebo-controlled trial.

BACKGROUND: Invasive pulmonary aspergillosis (IPA) is a significant problem in patients with chemotherapy-induced prolonged neutropenia. Because pulmonary deposition of conidia is the first step in developing IPA, we hypothesized that inhalation of liposomal amphotericin B would prevent IPA. METHODS: We performed a randomized, placebo-controlled trial of patients with hematologic disease with expected neutropenia for >or=10 days. Patients were randomized to receive liposomal amphotericin B or placebo inhalation twice a week, using an adaptive aerosol delivery system, until neutrophil counts increased to >300 cells/mm3. In subsequent neutropenic episodes, the assigned treatment was restarted. The primary end point was the occurrence of IPA according to European Organization for Research and the Treatment of Cancer-Mycoses Study Group definitions. Kaplan-Meier curves were compared with log-rank tests for intent-to-treat and on-treatment populations. RESULTS: A total of 271 patients were studied during 407 neutropenic episodes. According to the intent-to-treat analysis, 18 of 132 patients in the placebo group developed IPA versus 6 of 139 patients in the liposomal amphotericin B group (odds ratio, 0.26; 95% confidence interval, 0.09-0.72; P=.005). According to the on-treatment analysis, 13 of 97 patients receiving placebo versus 2 of 91 receiving liposomal amphotericin B developed IPA (odds ratio, 0.14; 95% confidence interval, 0.02-0.66; P=.007). Some adverse effects, but none serious, in the liposomal amphotericin B group were reported, most frequently coughing (16 patients vs. 1 patient; P=.002). CONCLUSION: In high-risk patients, prophylactic inhalation of liposomal amphotericin B significantly reduced the incidence of IPA.

Pathophysiology of unilateral pulmonary aspergillosis in an experimental rat model.

Because little is known about the pathophysiology of invasive pulmonary aspergillosis (IPA), we examined changes in pulmonary and general physiology during this disease in an animal model. In a model of fatal left-sided IPA, 19 persistently neutropenic rats were monitored for clinical signs including body temperature, body weight and respiratory distress. A separate group of nine rats with IPA was used for measurements of arterial blood pressure, arterial O2 and CO2 pressure, lung compliance and surfactant function. Body temperature and body weight decreased, whereas respiratory distress increased during progression of the disease. Compared to uninfected controls, in rats with IPA arterial blood pressure and lung compliance were significantly lower, and left lung minimal surface tension was significantly higher. Right lung surfactant function was not affected. Arterial O2 and CO2 pressures were not different between rats with IPA and uninfected controls. Infection with Aspergillus fumigatus in neutropenic rats resulted in hypothermia, body weight loss and respiratory distress. Loss of left lung function was probably compensated by the uninfected right lung, even in a late stage of the disease. Circulatory failure was a major feature in the terminal phase of the infection.

Long-circulating sterically stabilized liposomes in the treatment of infections.

The administration of antimicrobial agents encapsulated in long-circulating sterically stabilized liposomes results in a considerable enhancement of therapeutic efficacy compared with the agents in the free form. After liposomal encapsulation, the pharmacokinetics of the antimicrobial agents is significantly changed. An increase in circulation time and reduction in toxic side effects of the agents are observed. In contrast to other types of long-circulating liposomes, an important characteristic of these sterically stabilized liposomes is that their prolonged blood circulation time is, to a high degree, independent of liposome characteristics such as liposome particle size, charge and lipid composition (rigidity) of the bilayer, and lipid dose. This provides the opportunity to manipulate antibiotic release from these liposomes at the site of infection, which is important in view of the differences in pharmacodynamics of different antibiotics and can be done without compromising blood circulation time and degree of target localization of these liposomes. Depending on the liposome characteristics and the agent encapsulated, antibiotic delivery to the infected site is achieved, or the liposomes act as a micro-reservoir function for the antibiotic. In experimental models of localized or disseminated bacterial and fungal infections, the sterically stabilized liposomes have successfully been used to improve antibiotic treatment using representative agents of various classes of antibacterial agents such as the beta-lactams, the aminoglycosides, and the quinolones or the antifungal agent amphotericin B. Extensive biodistribution studies have been performed. Critical factors that contribute to liposome target localization in infected tissue have been elucidated. Liposome-related factors that were investigated were poly(ethylene glycol) density, particle size, bilayer fluidity, negative surface charge, and circulation kinetics. Host-related factors focused on the components of the inflammatory response.

Effect of amphotericin B treatment on kinetics of cytokines and parameters of fungal load in neutropenic rats with invasive pulmonary aspergillosis.

OBJECTIVE: The kinetics of various parameters of fungal load and cytokines were investigated, in order to acquire insight into the pathogenesis of invasive pulmonary aspergillosis (IPA) during antifungal treatment with amphotericin B. METHODS: Neutropenic rats with left-sided IPA received either treatment with amphotericin B or remained untreated. At 0, 4, 8, 16, 24, 48, 72 and 120 h after fungal inoculation, the rats were dissected. The size of the macroscopic pulmonary lesions, the number of cfu and amounts of chitin were determined in the infected left lung. Galactomannan concentrations were measured both in the left lung and serum. The cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-1beta, IL-6, interferon (IFN)-gamma, IL-4, IL-10, and the chemokines macrophage inflammatory protein (MIP)-2 and monocyte chemoattractant protein (MCP)-1 were determined quantitatively by ELISA in the infected left lung, uninfected right lung and serum. RESULTS: Amphotericin B treatment of IPA resulted in changed aspect of pulmonary lesions and significantly reduced levels of left lung chitin (72 and 120 h), left lung galactomannan (72 and 120 h) and serum galactomannan (120 h), but not left lung cfu, compared with untreated infected rats. In addition, amphotericin B treatment resulted in a significant decrease in levels of left lung IL-6 (at 72 and 120 h), MIP-2 (at 120 h) and MCP-1 (at 120 h). No local or systemic increases in TNF-alpha, IL-1beta or IFN-gamma were observed during infection. CONCLUSION: It is concluded that treatment with amphotericin B results in decreased fungal load in the infected lung. This reduction in fungal load probably results in a decreased local inflammatory response, as measured by decreased levels of IL-6, MIP-2 and MCP-1 in the infected lung.

Galactomannan detection in computerized tomography-based broncho-alveolar lavage fluid and serum in haematological patients at risk for invasive pulmonary aspergillosis.

We determined the value of galactomannan (GM) detection in computerized tomography (CT)-based broncho-alveolar lavage (BAL) fluid and serum for the diagnosis of invasive pulmonary aspergillosis (IPA) in haemato-oncological patients with neutropenia. CT of the thorax and BAL were performed systematically at predefined clinical indications. GM was determined by sandwich enzyme-linked immunosorbent assay; the clinicians were unaware of the results. Of 160 patients, 17 patients (10.6%) presented with proven, probable or suspected IPA. The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of GM detection in CT-based BAL fluid were all 100%. For GM detection in serially sampled serum, the sensitivity was 47%, the specificity 93%, the PPV 73% and the NPV 82%. A non-blinded follow-up study was performed to validate these results. In this study, 22 of 198 patients (11.1%) presented with IPA, and the sensitivity, specificity, PPV and NPV of GM detection in CT-based BAL fluid were 85%, 100%, 100% and 88% respectively. None of BAL fluids obtained after antifungal treatment of 3 d or more were positive. These results indicate that, when CT is used systematically and at an early stage, GM detection in CT-based BAL fluid has a high PPV for diagnosing IPA early in untreated patients.

Enhanced antifungal efficacy in experimental invasive pulmonary aspergillosis by combination of AmBisome with Fungizone as assessed by several parameters of antifungal response.

In common with a proportion of patients with invasive pulmonary aspergillosis (IPA), the efficacy of AmBisome treatment regimens in our rat model remains suboptimal. To investigate whether this might be the result of initially low antifungal activity of amphotericin B at the site of infection when administered in the liposomal form, Fungizone was added to AmBisome at the start of treatment. Groups of granulocytopenic rats with left-sided IPA received 10 day treatment regimens with either AmBisome 10 mg/kg/day (n = 25) or AmBisome 10 mg/kg/day combined with a single dose of Fungizone 1 mg/kg at day 1 (n = 27). Parameters of treatment response included survival, serum galactomannan (GM), size and quality of pulmonary macroscopic lesions, lung weight, viable fungal counts (cfu) and chitin content of the infected lung, and extra-pulmonary disseminated fungal infection. In a separate experiment the significance of early start of treatment to obtain therapeutic efficacy was investigated. Compared with untreated controls, both treatment regimens showed a significant increase in survival and change in parameters of fungal infection except left lung cfu. The combination treatment showed a significant increase in survival compared with AmBisome monotherapy (P = 0.02) and a significant decrease in left lung chitin content (P = 0.03). Differences in circulating GM concentrations between the two treatment regimes approached significance (P = 0.06). Delay in the start of treatment from 16 to 24 h after fungal inoculation resulted in a significant decrease in therapeutic efficacy (P = 0.02). It is concluded that the efficacy of AmBisome therapy can be enhanced by the addition of Fungizone at the start of treatment. This is probably a result of active amphotericin B being immediately available in the lung at the start of treatment.

Scintigraphic imaging using 99mTc-labeled PEG liposomes allows early detection of experimental invasive pulmonary aspergillosis in neutropenic rats.

The value of scintigraphic imaging using 99mTc labeled poly(ethyleneglycol) (PEG) -liposomes for detecting invasive pulmonary aspergillosis at different stages of the disease was investigated in a rat model. At 24, 48, 72, 120 and 168 h after fungal inoculation scintigraphic images were obtained and biodistribution of the radiolabel was determined. Findings were compared with serum galactomannan detection and other parameters of progression of fungal infection. At 48 h liposomal uptake in the infected left lung was increased significantly and 82% of the scintigraphic images was assessed positive. Serum galactomannan was only detected at 72 h and later. Liposomal uptake in the infected left lung increased over time and was significantly correlated with both the size of the pulmonary hemorrhagic lesion and the levels of circulating galactomannan. It was concluded that scintigraphic imaging using 99mTc-PEG-liposomes allows early detection of invasive pulmonary aspergillosis in this model, and that liposomal uptake in the infected lung was strongly associated with the severity of the disease.