Assessment of the impact of clinical recommendations on antibiotic use for CAP and HCAP: results from an implementation program in an Academic Hospital.

BACKGROUND: Local guidelines and recommendations to treat common infectious diseases are a cornerstone of most Antimicrobial Stewardship programs. The evaluation of the adherence to guidelines is an effective quality measure of the programs themselves; the proposed evaluation model aimed at examining antibiotic treatment for pneumonia. STUDY DESIGN: A retrospective pre-post intervention study was conducted in a North-Eastern Italian Academic Hospital. METHODS: 231 patients with Community-Acquired Pneumonia and 95 with Healthcare-Associated Pneumonia were divided into pre- and post-intervention groups (188 and 138, respectively). A course and a pocket summary of Pneumonia Regional Recommendations were the stewardship activities adopted. The compliance degree of prescriptions with Regional Recommendations was tested for drug(s), dosage and duration of treatment in both groups for Community-Acquired and Healthcare-Associated Pneumonia and a comparison with International guidelines was performed. RESULTS: A significant improvement in the compliance with Regional Recommendations for the variable drug emerged for Community-Acquired (38.8% vs 52.2%), but not for Healthcare-Associated Pneumonia; no significant variation in compliance was registered for dosage and duration of treatment. The significant decrease in consumption of levofloxacin showed the positive impact of the Regional Antimicrobial Stewardship programs. A high level of adherence to International Guidelines for the variable drug for Community-Acquired Pneumonia was found in both groups (75.5% and 77.2%, respectively). CONCLUSIONS: Our study highlighted that room for improvement in antibiotic prescription in Community-Acquired and Healthcare-Associated Pneumonia currently remains. New strategies for a better use of the adopted tools and definition of new antimicrobial stewardship initiatives are needed to improve compliance to Regional Recommendations.

Antifungal susceptibility testing in Candida, Aspergillus and Cryptococcus infections: are the MICs useful for clinicians?

BACKGROUND: Invasive fungal infections (IFIs) represent a global issue and affect various patient populations. In recent years, resistant fungal isolates showing increased azole or echinocandin MICs have been reported, and their potential clinical impact has been investigated. AIMS: To provide an update on the epidemiology of resistance among fungi (e.g., Candida spp., Aspergillus spp., and Cryptococcus spp.) and to offer a critical appraisal of the relevant literature regarding the impact of MICs on clinical outcome in patients with IFI. SOURCES: PubMed search with relevant keywords along with a personal collection of relevant publications. CONTENT: Although antifungal resistance has been associated with a poorer response to antifungal therapy in various studies, other factors such as comorbidities, septic shock and source of infection appear to be key determinants affecting the clinical outcome of patients with IFI. IMPLICATIONS: Future international collaborative studies are required to tease out the relative contribution of in vitro antifungal resistance on patient outcomes, thus enabling the optimization of IFI management.

Pharmacodynamics of teicoplanin against MRSA.

OBJECTIVES: The overall study aim was to identify the relevant preclinical teicoplanin pharmacokinetic (PK)/pharmacodynamic (PD) indices to predict efficacy and suppression of resistance in MRSA infection. METHODS: A hollow-fibre infection model and a neutropenic murine thigh infection model were developed. The PK/PD data generated were modelled using a non-parametric population modelling approach with Pmetrics. The posterior Bayesian estimates derived were used to study the exposure-effect relationships. Monte Carlo simulations from previously developed population PK models in adults and children were conducted to explore the probability of target attainment (PTA) for teicoplanin dosage regimens against the current EUCAST WT susceptibility range. RESULTS: There was a concentration-dependent activity of teicoplanin in both the in vitro and in vivo models. A total in vivo AUC/MIC of 610.4 (total AUC of 305.2 mg·h/L) for an MRSA strain with an MIC of 0.5 mg/L was needed for efficacy (2 log10 cell kill) against a total bacterial population. A total AUC/MIC ratio of ∼1500 (total AUC of ∼750 mg·h/L) was needed to suppress the emergence of resistance. The PTA analyses showed that adult and paediatric patients receiving a standard regimen were only successfully treated for the in vivo bactericidal target if the MIC was ≤0.125 mg/L in adults and ≤0.064 mg/L in children. CONCLUSIONS: This study improves our understanding of teicoplanin PD against MRSA and defines an in vivo AUC/MIC target for efficacy and suppression of resistance. Additional studies are needed to further corroborate the PK/PD index in a variety of infection models and in patients.

Methicillin-resistant Staphylococcus aureus infections: A review of the currently available treatment options.

This review is the result of discussions that took place at the 5th MRSA Working Group Consensus Meeting and explores the possible treatment options available for different types of infections due to methicillin-resistant Staphylococcus aureus (MRSA), focusing on those antibiotics that could represent a valid alternative to vancomycin. In fact, whilst vancomycin remains a viable option, its therapy is moving towards individualised dosing. Other drugs, such as the new lipoglycopeptides (oritavancin, dalbavancin and telavancin) and fifth-generation cephalosporins (ceftaroline and ceftobiprole), are showing good in vitro potency and in vivo efficacy, especially for patients infected with micro-organisms with higher vancomycin minimum inhibitory concentrations (MICs). Tedizolid is an attractive agent for use both in hospital and community settings, but the post-marketing data will better clarify its potential. Daptomycin and linezolid have shown non-inferiority to vancomycin in the treatment of MRSA bacteraemia and non-inferiority/superiority to vancomycin in the treatment of hospital-acquired pneumonia. Thus, several options are available, but more data from clinical practice, especially for invasive infections, are needed to assign specific roles to each antibiotic and to definitely include them in the new antibacterial armamentarium.

Antiretroviral blood levels in HIV/HCV-coinfected patients with cirrhosis after liver transplant: a report of three cases.

Since the introduction of combined antiretroviral therapy, human immunodeficiency virus (HIV) infection is no longer a contraindication for solid organ transplantation. In HIV/hepatitis C virus (HCV)-coinfected patients undergoing liver transplantation, HCV-related cirrhosis, drug-drug interactions, and calcineurin inhibitors-related toxicity affect clinical outcomes. Therapeutic drug monitoring can be useful to assess antiretroviral over- or underexposure in this cohort. We report the clinical characteristics along with antiretroviral trough levels of maraviroc, darunavir, and etravirine in 3 HIV/HCV-coinfected liver transplant recipients who developed post-transplant liver cirrhosis.

Population pharmacokinetics of teicoplanin in children.

Teicoplanin is frequently administered to treat Gram-positive infections in pediatric patients. However, not enough is known about the pharmacokinetics (PK) of teicoplanin in children to justify the optimal dosing regimen. The aim of this study was to determine the population PK of teicoplanin in children and evaluate the current dosage regimens. A PK hospital-based study was conducted. Current dosage recommendations were used for children up to 16 years of age. Thirty-nine children were recruited. Serum samples were collected at the first dose interval (1, 3, 6, and 24 h) and at steady state. A standard 2-compartment PK model was developed, followed by structural models that incorporated weight. Weight was allowed to affect clearance (CL) using linear and allometric scaling terms. The linear model best accounted for the observed data and was subsequently chosen for Monte Carlo simulations. The PK parameter medians/means (standard deviation [SD]) were as follows: CL, [0.019/0.023 (0.01)] × weight liters/h/kg of body weight; volume, 2.282/4.138 liters (4.14 liters); first-order rate constant from the central to peripheral compartment (Kcp), 0.474/3.876 h(-1) (8.16 h(-1)); and first-order rate constant from peripheral to central compartment (Kpc), 0.292/3.994 h(-1) (8.93 h(-1)). The percentage of patients with a minimum concentration of drug in serum (Cmin) of <10 mg/liter was 53.85%. The median/mean (SD) total population area under the concentration-time curve (AUC) was 619/527.05 mg · h/liter (166.03 mg · h/liter). Based on Monte Carlo simulations, only 30.04% (median AUC, 507.04 mg · h/liter), 44.88% (494.1 mg · h/liter), and 60.54% (452.03 mg · h/liter) of patients weighing 50, 25, and 10 kg, respectively, attained trough concentrations of >10 mg/liter by day 4 of treatment. The teicoplanin population PK is highly variable in children, with a wider AUC distribution spread than for adults. Therapeutic drug monitoring should be a routine requirement to minimize suboptimal concentrations. (This trial has been registered in the European Clinical Trials Database Registry [EudraCT] under registration number 2012-005738-12.).

Daptomycin underexposure in a young intravenous drug user who was affected by life-threatening Staphylococcus aureus-complicated skin and soft tissue infection associated with bacteraemia.

We describe the case of an intravenous drug user affected by life-threatening Staphylococcus aureus-complicated skin and soft tissue infection with associated bacteraemia who, while on replacement therapy with methadone, required 11 mg/kg/day daptomycin to achieve trough (Cmin) and peak (Cmax) plasma levels similar to those observed with the standard dosage of 6 mg/kg in healthy volunteers (mean ± standard deviation: Cmin 12.35 ± 0.80 mg/L, Cmax 63.90 ± 8.71 mg/L). Clinical pharmacological advice based on real time therapeutic drug monitoring may be helpful for optimizing daptomycin exposure in these patients. Physicians should take into account that dosages much higher than the standard ones may be needed, probably as a consequence of augmented drug clearance.

Antibiotic therapy in hematological neutropenic patients: what is the news?

Bacterial infection is a very common complication in hematological neutropenic patients whose treatment is extremely challenging for several reasons. First, they are frequently caused by resistant pathogens (multidrug resistant (MDR)), and this may limit the availability of effective therapeutic weapons. Second, these patients often present peculiar pathophysiological conditions that may alter the pharmacokinetic behavior of antimicrobials, and this may explain the need for a new administration schedule and new dosing regimens of antibiotics in this setting. In an era in which there are only few new therapeutic weapons for the treatment of MDR bacterial infections, while advocating for new drugs, what could be effectively done nowadays is to increase the knowledge on appropriateness of the use of currently available drugs to improve clinical outcome and to preserve their activity.

Italian guidelines for diagnosis, prevention, and treatment of invasive fungal infections in solid organ transplant recipients.

Use of various induction regimens, of novel immunosuppressive agents, and of newer prophylactic strategies continues to change the pattern of infections among solid organ transplant (SOT) recipients. Although invasive fungal infections (IFIs) occur at a lower incidence than bacterial and viral infections in this population, they remain a major cause of morbidity and mortality worldwide. In March 2008, a panel of Italian experts on fungal infections and organ transplantation convened in Castel Gandolfo (Rome) to develop consensus guidelines for the diagnosis, prevention, and treatment of IFIs among SOT recipients. We discussed the definitions, microbiological and radiological diagnoses, prophylaxis, empirical treatment, and therapy of established disease. Throughout the consensus document, recommendations as clinical guidelines were rated according to the standard scoring system of the Infectious Diseases Society of America and the United Stated Public Health Service.

Long-term outcomes of orthotopic liver transplantation in human immunodeficiency virus-infected patients and comparison with human immunodeficiency virus-negative cases.

Human immunodeficiency virus (HIV) positivity is no longer a contraindication for orthotopic liver transplantation (OLT) due to the efficacy of antiretroviral therapy. The aim of this study was to compare OLT among HIV-positive and HIV-negative cohorts; the results were also stratified for hepatitis C virus (HCV) coinfection. Between 2004 and 2009, all HIV-infected patients undergoing OLT from heart-beating deceased donors (n=27) were compared with an HIV-negative cohort (n = 27). The pure HCV infection rate was similar between HIV-positive and HIV-negative subjects (63% each). HIV-positive recipients were younger (P=.013). The CD4 count for HIV-positive subjects was 376 ± 156 at transplantation. The mean model for end-stage liver disease (MELD) score at transplantation was 15 ± 7 in both groups (P=.92). No differences were observed for donor age (P=.72) or time on the waiting list (P=.56). The median follow-up was 26 (range, 1-64) and 27 months (range, 1-48) for HIV and non-HIV recipients, respectively (P=.85). The estimated 1-, 3-, and 5-year patient and graft survival rates were 88%, 83%, and 83% versus 100%, 73%, and 73% (P=.95), and 92%, 87%, and 87% versus 95%, 88%, and 88% (P=.59) for HIV and non-HIV cases, respectively. HIV/HCV-coinfected patients were younger, namely 47 (range, 40-53) versus 52 years (range, 37-68; P=.003), and displayed lower MELD scores at transplantation compared with HCV-mono-infected patients 10 (range, 7-19) versus 17 (range, 8-30) (P=.008). For HIV/HCV-coinfected and HCV-mono-infected cases the estimated 1-, 3-, and 5-year patients and graft survival rates were respectively 93%, 76%, and 76% versus 100%, 70%, and 60% (P=.99) and 93%, 84%, and 84% versus 100%, 70%, and 60% (P=.64), respectively. No difference was observed in the histological severity of HCV recurrence. In conclusion, under specific, well-determined conditions, OLT can be a safe, efficacious procedure in HIV patients.

The Charta of Milan: basic criteria for the appropriate and accurate use of antibiotics: recommendations of the Italian Society of Chemotherapy.

This article summarizes the recommendations drawn up by the Italian Society of Chemotherapy regarding the proper use of antimicrobial agents for infectious diseases.

Treatment of post-traumatic hand Staphylococcus aureus osteomyelitis with oral linezolid.

The Authors report on the use of linezolid for the treatment of three patients with osteomyelitis. All three patients had post-traumatic multisensitive hand bone methicillin-susceptible Staphylococcus aureus osteomyelitis, which did not respond to antimicrobial regimens including drugs in vitro active against the isolated strains. Clinical cure and microbiologic eradication was obtained with oral linezolid in all three patients. Linezolid was well tolerated. Mild thrombocytopenia was observed in one patient at the end of the third week of treatment and it was promptly resolved after the discontinuation of linezolid. Linezolid minimum inhibitory concentrations (MICs) consisted of 2 mg/l for all three S. aureus isolates while the bactericidal activity in vitro was not present up to the linezolid concentration of 32 mg/l. In spite of a lack of in vitro bactericidal activity, linezolid was effective in curing the patients and eradicating the infection. Trough and peak plasma concentrations of linezolid were above the MICs of the isolates. These values ranged from 3.93 to 14.95 mg/l at trough and 5.03 to 25.91 mg/l at peak. The oral bioavailability, pharmacokinetic profile and antibacterial spectrum of linezolid make this oxazolidonone antimicrobial an attractive drug for the treatment of chronic osteomyelitis. Prolonged administration requires careful surveillance for side effects, until these complications are better understood.

Pharmacology of drugs for hyperuricemia. Mechanisms, kinetics and interactions.

The pharmacological profile of drugs for hyperuricemia is reviewed. These agents may reduce the amount of uric acid in blood by means of two different ways: (1) by reducing uric acid production through the inhibition of the enzyme xanthine oxidase (as allopurinol); (2) by increasing uric acid clearance through an inhibition of its renal tubular reabsorption (as probenecid), or through its metabolic conversion to a more soluble compound (as urate oxidase). Allopurinol is rapidly converted in the body to the active metabolite oxypurinol whose total body exposure may be 20-fold greater than that of the parent compound due to a much longer elimination half-life. Allopurinol undergoes several pharmacokinetic interactions with concomitant administered drugs, some of which may be potentially hazardous (especially with mercaptopurine and azathioprine). Probenecid is an uricosuric agent which undergoes extensive hepatic metabolism and whose elimination after high doses may become dose dependent. It may inhibit renal tubular secretion of several coadministered agents, including methotrexate and sulphonylureas. Rasburicase is a recombinant form of the enzyme urate oxidase which catalyzes the conversion of uric acid to the more soluble compound allantoin. Unlike allopurinol, it does not promote accumulation of hypoxanthine and xanthine in plasma, thus preventing the risk of xanthine nephropathy. Rasburicase showed no significant accumulation in children after administration of either 0.15 or 0.20 mg/kg/daily for 5 days. Rasburicase probably undergoes peptide hydrolysis and in in vitro studies was shown neither to inhibit or induce cytochrome P450 isoenzymes nor to interact with several drugs, so that no relevant interaction is expected during cotreatment in patients.

Antimicrobial agents in elective surgery: prophylaxis or "early therapy"?

A lack of a clear distinction between antimicrobial prophylaxis and therapy still exists in the surgical setting. Major concerns are: 1) Which surgical procedures are eligible for antimicrobial prophylaxis? 2) Which kind of antimicrobial agent should be used for surgical prophylaxis? 3) What is the optimal timing for administering antimicrobial prophylaxis and how long should administration be continued? In this paper we assess the rationales leading to the following answers: 1) Only clean-contaminated and prosthetic clean operations should be eligible for antimicrobial prophylaxis, whereas contaminated or dirty operations should be eligible for "early therapy". 2) First- or second-generation cephalosporins or aminopenicillin/beta-lactamase inhibitors are optimal choices for surgical prophylaxis, depending on location of the surgical wound. 3) The highest licensed dosage of the chosen antimicrobial agent should be administered at induction of anesthesia and redosing should be considered when the intervention lasts more than 2 antibiotic half-lives. This allows maintenance of optimal drug exposure against the potential pathogens in plasma and in the extracellular environment of the potentially contaminated tissues for the entire procedure and for some hours after wound closure. Post-surgical doses are not recommended in most cases whereas ultra-short prophylaxis is preferred.