Sequential antibiotic therapy for cost containment in the hospital setting: why not?

Microbiological Characterization of VNRX-5236, a Broad-Spectrum β-Lactamase Inhibitor for Rescue of the Orally Bioavailable Cephalosporin Ceftibuten as a Carbapenem-Sparing Agent against Strains of Enterobacterales Expressing Extended-Spectrum β-Lactamases and Serine Carbapenemases

There is an urgent need for oral agents to combat resistant Gram-negative pathogens. Here, we describe the characterization of VNRX-5236, a broad-spectrum boronic acid β-lactamase inhibitor (BLI), and its orally bioavailable etzadroxil prodrug, VNRX-7145. VNRX-7145 is being developed in combination with ceftibuten, an oral cephalosporin, to combat strains of Enterobacterales expressing extended-spectrum β-lactamases (ESBLs) and serine carbapenemases. VNRX-5236 is a reversible covalent inhibitor of serine β-lactamases, with inactivation efficiencies on the order of 10⁴ M⁻¹ · sec⁻¹, and prolonged active site residence times (t_1/2, 5 to 46 min). The spectrum of inhibition includes Ambler class A ESBLs, class C cephalosporinases, and class A and D carbapenemases (KPC and OXA-48, respectively). Rescue of ceftibuten by VNRX-5236 (fixed at 4 μg/ml) in isogenic strains of Escherichia coli expressing class A, C, or D β-lactamases demonstrated an expanded spectrum of activity relative to oral comparators, including investigational penems, sulopenem, and tebipenem. VNRX-5236 rescued ceftibuten activity in clinical isolates of Enterobacterales expressing ESBLs (MIC₉₀, 0.25 μg/ml), KPCs (MIC₉₀, 1 μg/ml), class C cephalosporinases (MIC₉₀, 1 μg/ml), and OXA-48-type carbapenemases (MIC₉₀, 1 μg/ml). Frequency of resistance studies demonstrated a low propensity for recovery of resistant variants at 4× the MIC of the ceftibuten/VNRX-5236 combination. In vivo, whereas ceftibuten alone was ineffective (50% effective dose [ED₅₀], >128 mg/kg), ceftibuten/VNRX-7145 administered orally protected mice from lethal septicemia caused by Klebsiella pneumoniae producing KPC carbapenemase (ED₅₀, 12.9 mg/kg). The data demonstrate potent, broad-spectrum rescue of ceftibuten activity by VNRX-5236 in clinical isolates of cephalosporin-resistant and carbapenem-resistant Enterobacterales.

Building a Successful Infection Prevention Program: Key Components, Processes, and Economics

Infection control is the discipline responsible for preventing health care-associated infections (HAIs) and has grown from an anonymous field, to a highly visible, multidisciplinary field of incredible importance. There has been increasing focus on prevention rather than control of HAIs. Infection prevention programs (IPPs) have enormous scope that spans multiple disciplines. Infection control and the prevention and elimination of HAIs can no longer be compartmentalized. This article discusses the structure and responsibilities of an IPP, the regulatory pressures and opportunities that these programs face, and how to build and manage a successful program.

Addressing Concerns about Changing the Route of Antimicrobial Administration from Intravenous to Oral in Adult Inpatients

BACKGROUND

Many health care institutions are in the process of establishing antimicrobial stewardship programs. Changing the route of administration of antimicrobial agents from intravenous to oral (IV to PO) is a simple, well-recognized intervention that is often part of an antimicrobial stewardship program. However, the attending health care team may have concerns about making this switch.

OBJECTIVES

To provide insights into common concerns related to IV to PO conversion, with the aim of helping antimicrobial stewardship teams to address them.

DATA SOURCES

Published clinical trials and reviews were identified from a literature search of Ovid MEDLINE with the keywords (step down or switch or conversion or transition or sequential) and (antibiotics or antibacterial agents or antimicrobial or anti-infective agents).

DATA SYNTHESIS

The following issues are addressed in this review: benefits of the oral route, serum concentrations yielded by the oral formulation, source of pharmacokinetic data, clinical outcomes, provision of care in the intensive care unit, fear of therapeutic failure, and administration of antimicrobials via feeding tube.

CONCLUSIONS

When considering a change to oral therapy, it is important to have a thorough understanding of key aspects of the antimicrobial agent, the patient, and the disease being treated. The antimicrobial stewardship team has an important role in facilitating IV to PO conversion, educating prescribers, and addressing any concerns or reservations that may interfere with timely transition from IV to PO administration.

Efficacy of N-Acetyl-Cysteine in Combination with Thiamphenicol in Sequential (Intramuscular/Aerosol) Therapy of Upper Respiratory Tract Infections Even When Sustained by Bacterial Biofilms

A total of 102 patients with recurrent upper respiratory tract infections underwent microbiological exploration with appropriate sampling and direct biopsies of the infected sites. Therapy was then started and on day 1 each patient received two intramuscular injections of thiamphenicol glycinate acetylcysteinate (TGA). From day 2 to 10 sequential therapy with the same drug was continued employing TGA administered by aerosol. All putative etiologic agents recovered were susceptible to thiamphenicol and only 24 demonstrated the ability to produce in vitro biofilms. The organisms comprised 10 Staphylococcus aureus, 6 Streptococcus pyogenes, 4 Streptococcus pneumoniae and 3 Haemophilus influenzae. Of the 24 subjects in whom biofilms were demonstrated to be present in vivo by Scanning Electron Microscopy, clinical and bacteriological cure was obtained in 21 cases (87.5%) following sequential therapy with TGA. Failures were considered to be persistent signs and symptoms at day 15 after initiation of treatment and lack of eradication of 3 S. aureus strains, despite their in vitro susceptibility to thiamphenicol. Very few adverse events attributable to TGA were reported in this cohort of patients. In no case was discontinuation of treatment deemed necessary by the attending physician.

Building a successful infection prevention program: key components, processes, and economics

Infection control is the discipline responsible for preventing nosocomial infections. There has been an increasing focus on prevention rather than control of hospital-acquired infections. Individuals working in infection control have seen their titles change from infection control practitioner to infection control professional and most recently to infection preventionist (IP), emphasizing their critical role in protecting patients. The responsibilities of IPs span multiple disciplines including medicine, surgery, nursing, occupational health, microbiology, pharmacy, sterilization and disinfection, emergency medicine, and information technology. This article discusses the structure and responsibilities of an infection control program and the regulatory pressures and opportunities the program faces.

Health economics of use fluoroquinolones to treat patients with community-acquired pneumonia

Respiratory diseases account for approximately 10% of all hospital admissions in the United States. Pneumonia constitutes 35% of these cases, with an average length of stay (LOS) of 5.1 days. It is estimated that $8.4 billion to $10 billion of all annual US hospital expenditures are attributable to community-acquired pneumonia (CAP). As such, medical decisions, including empiric antibiotic choice, potentially exert an impact on hospital LOS and associated costs. In this review, we focus on the empiric antibiotic choices and associated costs of treatment for hospitalized patients with CAP, focusing on the use of fluoroquinolone therapy as recommended by the CAP guidelines.

Sequential therapy with cefuroxime and cefuroxime-axetil for community-acquired lower respiratory tract infection in the oldest old

BACKGROUND AND AIMS

Community acquired lower respiratory tract infection (CALRTI) is the most common infection requiring hospitalization in the elderly. Sequential antibiotic therapy offers the potential for earlier functional rehabilitation, shorter length of hospital stay and lower costs. We studied the efficacy and safety of an empiric sequential antibiotic therapy with cefuroxime-cefuroxime axetil in elderly patients hospitalized with a CALRTI.

METHODS

A prospective, randomized, open-label, in-hospital study of cefuroxime IV 750 mg tid for 10 days (IV group) vs cefuroxime 750 mg IV tid for 3 days, followed by cefuroxime-axetil PO 500 mg bid for 7 days (sequence group), when clinical (symptoms improved and fever disappeared) and/or laboratory response [decrease in C-reactive protein (CRP)] occurred.

RESULTS

A total of 142 patients, 71 (mean age: 83.3 (+/-6 SD), M/F ratio: 1.1) in the IV group, and 71 (mean age: 81.5 (+/-7 SD), M/F ratio: 1.5) in the sequence group, were included in the study. Eighty-three (58.4%) presented with radiologically confirmed pneumonia (CAP) and 59 (41.6%) with non-pneumonic LRTI (NPLRTI) (p=ns between study groups). Treatment was considered effective in 84.5% (60/71) of patients in the IV group and 80.3% (57/71) in the sequence group (p=ns). Therapy failed in 15% (21/142) of the study population (p=ns between study groups) and, after day 3 of therapy, 8.45% (6/71) failed in both study groups. By the end of treatment, two patients had died in each study group, and total in-hospital mortality was 8.5% (12/142, p=ns between study groups). The length of hospital stay (LOS) did not differ between the two study groups.

CONCLUSIONS

When a favorable clinical or biochemical response occurs on day 3 of IV cefuroxime therapy, further therapy with oral cefuroxime-axetil is as effective and safe as a full course of cefuroxime IV in elderly patients hospitalized with CALRTI. However, LOS was not reduced after sequential antibiotic therapy in this population.

A multidisciplinary approach to antimicrobial stewardship: evolution into the 21st century

In the 21st century, we face the problems of escalating antibiotic resistance, difficult-to-treat infections and slowed new drug development. Healthcare practitioners are increasingly recognising the importance of good antimicrobial stewardship. Various strategies such as formulary management, prior approval, clinical pathways, post-prescribing evaluation and intravenous to oral conversion have been used singly or in combination to improve prescribing and reduce costs. Combining a multifaceted approach with a full-time dedicated multidisciplinary team appears to be capable of yielding satisfactory clinical and economic outcomes and most importantly, sustaining efforts of antimicrobial stewardship. The multidisciplinary approach to antibiotic management should be tailored to fit the individual needs of an institution. More data are needed to document effects on curbing resistance.

The driving force in hospital formularies: economics versus efficacy

The rising cost of pharmaceuticals has created a focus on hospital cost containment. From 1990 to 2000, spending on prescription drugs increased 200%. Through a variety of mechanisms and contracting, hospital formularies have become increasingly more restrictive. Physician choice with regard to antibiotics specifically is becoming more limited. The field of pharmacoeconomics looks at the cost effectiveness of the drugs we use. The pressures on the pharmaceutical industry and hospitals are reviewed here with a discussion of antibiotic prophylaxis, new expensive therapies, and physician responsibility. The driving force behind hospital formulary design is often economic, whereas the physician desires variety and efficacy. This review discusses some of the key issues related to drug costs and expenditures.

Bioavailability of gatifloxacin by gastric tube administration with and without concomitant enteral feeding in critically ill patients

OBJECTIVE

Sequential intravenous-to-oral antimicrobial therapy with highly bioavailable antiinfective agents such as the fluoroquinolones may improve patient safety and decrease cost of infection management. However, physiologic changes associated with critical illness may alter drug absorption, distribution, and clearance, and concomitant enteral feeding may decrease fluoroquinolone bioavailability. We evaluated the effect of critical illness and concomitant gastric tube feeding on gatifloxacin bioavailability.

DESIGN

Prospective, randomized, single-dose, two-way crossover, pharmacokinetic study. SETTINGA tertiary, level-one, trauma center.

PATIENTS

Sixteen critically ill patients (baseline Acute Physiology and Chronic Health Evaluation II score >or=16) tolerating enteral nutrition administered by gastric tube (NG) for >or=12 hrs were randomized to receive gatifloxacin concurrently with continuous tube feeding or with interrupted tube feeds. Patients with renal insufficiency or those receiving concomitant fluoroquinolone therapy or postpyloric feeding were excluded. Patients received gatifloxacin 400 mg either by the intravenous or NG route followed by the alternative dosage form after a 72-hr washout period.

MEASUREMENTS AND MAIN RESULTS

Serial serum gatifloxacin concentrations (from 5 mins to 24 hrs) were analyzed using a validated high-performance liquid chromatography method. Bioavailability was determined as the ratio of NG/intravenous area under the concentration-time curve (AUC infinity ) measured by the trapezoidal method. Although there was no difference in the bioavailability between NG (AUC infinity : 38.0 [range 20.1 to 48.5] microg x h/mL) and intravenous (AUC infinity : 39.5 [range 24.1 to 63.1] microg x h/mL, p =.60) gatifloxacin (bioavailability: 98.5% [range 61.1% to 119.7%]), a wide variability was observed in three of eight patients (>30% reduction in bioavailability). Concomitant gastric tube feeding did not affect gatifloxacin bioavailability (interrupted tube feeds: 98.5% [range 61.1% to 119.7%]; continuous tube feeding: 109.0% [range 86.2% to 142.1%]; p =.42). Neither a period nor differential carryover effect was observed.

CONCLUSIONS

Although concomitant tube feeding did not affect gatifloxacin bioavailability, critical illness resulted in significant variability that may complicate the role of gatifloxacin in sequential intravenous-to-oral therapy. More research is needed to identify those patients in whom gatifloxacin bioavailability is reduced and for whom an empirical increase in gatifloxacin dose should be considered.

Antibiotic policies and control of resistance

PURPOSE OF THE REVIEW

The current worldwide pandemic of antibiotic resistance shows no signs of abating. It is clear that it is driven mainly by heavy and often inappropriate antibiotic use. Although control measures are widely practised, it is important that we assess their efficacy critically in order to concentrate expensive control efforts where they will be most effective. The past year has seen much activity in this area, with evidence-based assessments of the literature according to strict guidelines, as well as progress in basic science studies of mechanisms of resistance, and their causes and relations to pathogenicity and adaptability.

RECENT FINDINGS

The present review summarizes current developments in the causes of antibiotic resistance, the classification of antibiotic stewardship and control measures, the evidence base for their efficacy, current problems in hospital practice, the adaptability of bacteria, the content of antibiotic policies and anticipated activities.

SUMMARY

The conclusions from the published literature are that much of it that pertains to changing prescribing practices does not stand up to modern evidence-based analysis concepts. Nevertheless, we can learn from experience in changing other areas of medical practice. We must be pragmatic and must not expect to change the world, but rather take it step by step, recognizing barriers and measuring outcomes and quality indicators. Studies into the molecular basis of resistance confirm the superb genetic adaptability of micro-organisms. They will always be several steps ahead of us. Nevertheless, we are learning how to modify our prescribing habits to minimize resistance, not only by using antibiotics less frequently but also by altering dosing schedules in various ways.