Antibiotic stability related to temperature variations in elastomeric pumps used for outpatient parenteral antimicrobial therapy (OPAT)

Current practices and challenges of outpatient parenteral antimicrobial therapy: a narrative review

Extended hospitalization for infection management increases inpatient care costs and the risk of healthcare-associated adverse events, including infections. The growing global demand for healthcare, the diminishing availability of hospital beds and an increasing patient preference for care within their own home have been the primary drivers of the expansion of hospital-in-the-home programmes. Such programmes include the use of IV antimicrobials in outpatient settings, known as outpatient parenteral antimicrobial therapy (OPAT). However, OPAT practices vary globally. This review article aims to describe the current OPAT practices and challenges worldwide. OPAT practice begins with patient evaluation and selection using eligibility criteria, which requires collaboration between the interdisciplinary OPAT team, patients and caregivers. Depending on care requirements, eligible patients may be enrolled to various models of care, receiving medication by healthcare professionals at outpatient infusion centres, hospital clinics, home visits or through self-administration. OPAT can be used for the management of many infections where an effective oral treatment option is lacking. Various classes of parenteral antimicrobials, including β-lactams, aminoglycosides, glycopeptides, fluoroquinolones and antifungals such as echinocandins, are used globally in OPAT practice. Despite its benefits, OPAT has numerous challenges, including complications from medication administration devices, antimicrobial side effects, monitoring requirements, antimicrobial instability, patient non-adherence, patient OPAT rejection, and challenges related to OPAT team structure and administration, all of which impact its outcome. A negative outcome could include unplanned hospital readmission. Future research should focus on mitigating these challenges to enable optimization of the OPAT service and thereby maximize the documented benefits for the healthcare system, patients and healthcare providers.

Stability Studies of Antipseudomonal Beta Lactam Agents for Outpatient Therapy

Outpatient parenteral antimicrobial therapy (OPAT) is a useful treatment strategy against Pseudomonas aeruginosa and other multidrug-resistant bacteria. However, it is hindered by the lack of stability data for the administration of antibiotics under OPAT conditions. Our objective was to investigate the stability of nine antipseudomonal and broad-spectrum beta lactam antibiotics (aztreonam, cefepime, cefiderocol, ceftazidime, ceftazidime/avibactam, ceftolozane/tazobactam, meropenem, meropenem/vaborbactam, and piperacillin/tazobactam) to allow the spread of OPAT programs. All the antibiotics were diluted in 500 mL 0.9% sodium chloride and stored at 4, 25, 32, and 37 °C for 72 h in two different devices (infusion bags and elastomeric pumps). The solutions were considered stable if the color, clearness, and pH remained unchanged and if the percentage of intact drug was ≥90%. All the antimicrobials remained stable 72 h under refrigerated conditions and at least 30 h at 25 °C. At 32 °C, all the antibiotics except for meropenem and meropenem/vaborbactam remained stable for 24 h or more. At 37 °C, only aztreonam, piperacillin/tazobactam, cefepime, cefiderocol, and ceftolozane/tazobactam were stable for at least 24 h. The stability results were the same in the two devices tested. All the antibiotics studied are actual alternatives for the treatment of antipseudomonal or multidrug-resistant infections in OPAT programs, although the temperature of the devices is crucial to ensure antibiotic stability.

Stability of temocillin in outpatient parenteral antimicrobial therapy: is it a real option?

BACKGROUND

Temocillin is an interesting alternative to carbapenems for susceptible Enterobacteriaceae. Although its use in outpatient parenteral antimicrobial therapy (OPAT) programmes has generated interest, this has been hampered by the lack of stability data.

OBJECTIVES

The purpose of the present study was to evaluate the physical and chemical stability of temocillin at the recommended dose for its use in OPAT programmes, contained in polypropylene infusion bags or polyisoprene elastomeric devices at different temperatures, and to describe a novel LC-MS/MS developed for the quantification of temocillin.

METHODS

Temocillin daily dose (6 g) was diluted in 500 mL of 0.9% sodium chloride to obtain a final concentration of 12 g/L. This solution was stored at 4°C, 25°C, 32°C and 37°C for 72 h, both in polypropylene infusion bags and in polyisoprene elastomeric pumps. Physical and chemical stability were evaluated during 72 h after manufacturing. Solutions were considered stable if colour, clearness and pH remained unchanged and if the percentage of intact drug was ≥90%.

RESULTS

Temocillin attained the chemical stability criterion of ≥90% of the original concentration for the whole experiment in both devices at 4°C, 25°C and 32°C. At 37°C, temocillin was stable for 24 h but its concentration dropped below 90% from that timepoint. No precipitation occurred and minor colour changes were observed.

CONCLUSIONS

Temocillin is stable under OPAT conditions and it would be an appropriate candidate for the treatment of patients who can be discharged to complete therapy in an OPAT programme. For this study, an LC-MS/MS method was developed.

Stability Study of Fosfomycin in Elastomeric Pumps at 4 °C and 34 °C: Technical Bases for a Continuous Infusion Use for Outpatient Parenteral Antibiotic Therapy

BACKGROUND

Fosfomycin acts against aerobic Gram-/+ bacteria by blocking the synthesis of peptidoglycan. Its use has been currently re-evaluated for intravenous administration for the treatment of systemic infections by multidrug-resistant bacteria. Concentration-/time-dependent activity has been suggested, with potential clinical advantages from prolonged or continuous infusion. Nevertheless, little is known about Fosfomycin stability in elastomeric pumps. The aim of the present work was stability investigation before administration at 4 °C and during administration at 34 °C.

METHODS

InfectoFos® (InfectoPharm s.r.l., Milan, Italy) preparation for intravenous use in elastomeric pumps at 4 °C and 34 °C was analyzed following EMA guidelines for drug stability. Samples were analyzed with an ultra-high performance liquid chromatography coupled with tandem mass spectrometry method on a LX50® UHPLC system equipped with a QSight 220® (Perkin Elmer, Milan, Italy) tandem mass spectrometer.

RESULTS

Fosfomycin in elastomeric preparation is stable for at least 5 days at a storage temperature of 4 °C and 34 °C.

CONCLUSIONS

The results suggest Fosfomycin eligibility for continuous infusion even in the context of outpatient parenteral antibiotic therapy. Therefore, this approach should be tested in clinical and pharmacokinetic studies, in order to evaluate the possible gains in the pharmacokinetic profile and the clinical effectiveness.

Ampicillin Stability in a Portable Elastomeric Infusion Pump: A Step Forward in Outpatient Parenteral Antimicrobial Therapy

Outpatient parenteral antimicrobial therapy (OPAT) with continuous infusion pumps is postulated as a very promising solution to treat complicated infections, such as endocarditis or osteomyelitis, that require patients to stay in hospital during extended periods of time, thus reducing their quality of life and increasing the risk of complications. However, stability studies of drugs in elastomeric devices are scarce, which limits their use in OPAT. Therefore, we evaluated the stability of ampicillin in sodium chloride 0.9% at two different concentrations, 50 and 15 mg/mL, in an elastomeric infusion pump when stored in the refrigerator and subsequently in real-life conditions at two different temperatures, 25 and 32 °C, with and without the use of a cooling device. The 15 mg/mL ampicillin is stable for up to 72 h under refrigeration, allowing subsequent dosing at 25 °C for 24 h with and without a cooling device, but at 32 °C its concentration drops below 90% after 8 h. In contrast, 50 mg/mL ampicillin only remains stable for the first 24 h under refrigeration, and subsequent administration at room temperature is not possible, even with the use of a cooling system. Our data support that 15 mg/mL AMP is suitable for use in OPAT if the volume and rate of infusion are tailored to the dosage needs of antimicrobial treatments.

Real-Life Experience of Continuously Infused Ceftolozane/Tazobactam in Patients with Bronchiectasis and Multidrug-Resistant Pseudomonas aeruginosa Infection in the Outpatient Setting

(1) Background: Ceftolozane/tazobactam (C/T) is a novel β-lactam/β-lactamase inhibitor with excellent activity against the multidrug-resistant (MDR) P. aeruginosa. Continuous infusion (CI) dosing allows the optimization of pharmacokinetic and pharmacodynamic (PK/PD) properties of β-lactam antibiotics and may support patients' treatment as outpatients. (2) Methods: Adult patients receiving their entire course of C/T as a CI in the outpatient setting were retrospectively included in the study. The primary outcome evaluated was clinical resolution. The secondary outcomes evaluated were PK/PD target attainment (ƒT > 4 × MIC) and microbiologic clearance at the end of treatment. Therapeutic drug monitoring to assess C/T concentration was performed. (3) Results: Three patients were enrolled in the study and received 9 g of C/T in CI every 24 h. One patient received an additional course of antimicrobial therapy due to disease exacerbation six months after initial treatment, accounting for four evaluated treatments. The primary outcome was achieved in 3/4 treatments and the secondary outcome was achieved in 4/4 and 3/3, respectively. In all patients, free ceftolozane concentrations were >10 times higher than the EUCAST breakpoint (4 mg/L). (4) Conclusions: Elastomeric infusion of C/T delivered in CI can be an effective and convenient way to treat acute diseases caused by MDR-P. aeruginosa, avoid hospital admission, and contribute to infection control strategies. Despite the small number of enrolled patients, clinical and microbiological results support this strategy.

Widening the net: a literature review of antimicrobial agents with potential suitability for outpatient parenteral antimicrobial therapy services-the importance of storage and stability

OBJECTIVES

Outpatient parenteral antimicrobial therapy (OPAT) services using continuous infusions (CIs) of antimicrobial agents in elastomeric devices require evidence of acceptable stability of the agent over the infusion period. A period of refrigerated storage of filled devices, followed by the CI period, is useful for OPAT services but can present a significant challenge to the stability of drugs. The aims of this study were to review fresh-filled stability data on antimicrobials which would be useful for OPAT services and to identify suitable candidates for further assessment.

METHODS

Searches identified papers relating to stability assessments of antimicrobials for immediate use tested above 31°C using a stability-indicating method.

RESULTS

We identified 18 stability studies published in 12 papers between 2015 and 2020, assessing the stability of 10 agents. Aminopenicillins like ampicillin and amoxicillin appear too unstable for CI, while benzylpenicillin may benefit from buffering to improve its stability. Cephalosporins vary in their stability and CI periods of 24 hours may not be achievable. Of the carbapenems, there are insufficient data for doripenem but meropenem has been extensively studied and is unsuitable for CI longer than 6 hours. Voriconazole may be suitable for CI but needs further investigation.

CONCLUSIONS

Some drugs identified in our review are unlikely to be suitable for continuous infusion in OPAT services due to instability. Using a 'fresh-fill' approach, without refrigerated storage, may make some drugs useful while other agents should be considered for further assessment to Yellow Cover Document standards. The impact of buffering for penicillins should be assessed further.

Stability of Ampicillin plus Ceftriaxone Combined in Elastomeric Infusion Devices for Outpatient Parenteral Antimicrobial Therapy

Currently, ampicillin plus ceftriaxone (AC) is one of the preferred treatments for Enterococcus faecalis infective endocarditis. However, there is a lack of stability data for the combination of both drugs in elastomeric devices, so the inclusion of AC in Outpatient Parenteral Antimicrobial Therapy (OPAT) programs is challenging. The objective of the study was to determine the stability of AC in elastomeric pumps when stored at 8 ± 2 °C, 25 ± 2 °C, 30 ± 2 °C and 37 ± 2 °C using LC-MS/MS. The combination was diluted in 0.9% sodium chloride and the final concentrations were ampicillin 24 g/L plus ceftriaxone 8 g/L. Physical and chemical stability were evaluated at 12, 20, 24, 36 and 48 h after preparation. Stability was met at each time point if the percentage of intact drug was ≥90% of its respective baseline concentration and color and clearness remained unchanged. The drug combination was stable for 48 h when it was kept at 8 ± 2 °C. At 25 ± 2 °C and 30 ± 2 °C, they were stable for 24 h of storage. At 37 ± 2 °C, the stability criterion was not met at any time point. These results prove that AC could be included in OPAT programs using elastomeric infusion devices for the treatment of E. faecalis infections.

A review of evidence, antimicrobial stability, and feasibility considerations for OPAT continuous infusion

Outpatient parenteral antimicrobial therapy (OPAT) has been widely used in clinical practice for many decades because of its associated cost savings, reductions in inpatient hospital days, and decreases in hospital-associated infections. Despite this long history, evolving practice patterns and new drug delivery devices continue to present challenges as well as opportunities for clinicians when designing appropriate outpatient antimicrobial regimens. One such change is the increasing use of extended and continuous infusion (CI) of antimicrobials to optimize the achievement of pharmacokinetic and pharmacodynamic targets. Elastomeric devices are also becoming increasingly popular in OPAT, including for the delivery of CI. In this article, we review the clinical evidence for CI in OPAT, as well as practical considerations of patient preferences, cost, and antimicrobial stability.

Development of Thermoresponsive-Gel-Matrix-Embedded Amoxicillin Trihydrate-Loaded Bovine Serum Albumin Nanoparticles for Local Intranasal Therapy

A high dose of amoxicillin is recommended as the first-line therapy for acute bacterial rhinosinusitis (ABR). However, oral administration of amoxicillin is connected to many adverse reactions coupled with moderate bioavailability (~60%). Therefore, this study aimed to develop a topical nasal preparation of amoxicillin, employing a thermoresponsive nanogel system to increase nasal residence time and prolong drug release. Rheological investigations revealed that formulations containing 21−23% w/w Poloxamer 407 (P407) were in accordance with the requirement of nasal administration (gelling temperature ~35 °C). The average hydrodynamic diameter (<200 nm), pH (6.7−6.9), and hypertonic osmolality (611−663 mOsmol/L) of the in situ gelling nasal nanogel appeared as suitable characteristics for local rhinosinusitis treatment. Moreover, taking into account the mucoadhesive strength and drug release studies, the 21% w/w P407 could be considered as an optimized concentration for effective nasal delivery. Antibacterial activity studies showed that the ability of amoxicillin-loaded in situ gelling nasal nanogel to inhibit bacterial growth (five common ABR pathogens) preserved its effectiveness in comparison to 1 mg/mL amoxicillin aqueous solution as a positive control. Altogether, the developed amoxicillin-loaded in situ gelling thermoresponsive nasal nanogel can be a potential candidate for local antibiotic therapy in the nasal cavity.

Systematic review of the stability of antimicrobial agents in elastomeric devices for outpatient parenteral antimicrobial therapy services based on NHS Yellow Cover Document standards

BACKGROUND

In order to use aseptically prepared elastomeric infusers, outpatient parenteral antimicrobial therapy (OPAT) services require extended stability data for antimicrobial agents to assign a product shelf-life. In the UK, the relevant standards for stability testing and shelf-life assignment are published in 'A Standard Protocol for Deriving and Assessment of Stability-Part 1 (Aseptic Preparations-Small Molecules), commonly called the Yellow Covered Document (YCD). A previous systematic review published in 2017 failed to identify data on the stability of antimicrobials in elastomeric devices for OPAT services that met YCD requirements in force at the time. The aim of this review was to update that search, following a subsequent change to YCD requirements in 2017 and 2019 and expand that dataset to identify progress made in providing assurance about the stability of antimicrobial agents for OPAT services.

METHODS

Searches were undertaken for papers relating to extended stability of antimicrobials. Citations were included when antimicrobial shelf-life was assessed using a stability-indicating method and considered a period of storage, either refrigerated or at room temperature, followed by in-use testing at a temperature at or above 32°C.

RESULTS

Of 267 initial citations, six met the inclusion criteria and underwent full text review for data extraction. Included antimicrobials were cefazolin, ceftazidime, piperacillin/tazobactam, flucloxacillin and ceftolozane/tazobactam. Of these, only flucloxacillin and piperacillin demonstrated YCD compliant stability over the 24-hour infusion period while cefazolin, ceftazidime and ceftolozane/tazobactam could be infused over 12-hour period.

CONCLUSIONS

Contrary to the position found in 2017 review, high-quality data are now available to support the use of a number of antimicrobial agents in extended infusion in elastomeric devices for OPAT services. There is a need to expand the dataset, as well as developing international consensus on the ideal parameters for stability assessment of such infusions in elastomeric devices.

Successful Integration of Clinical Pharmacists in an OPAT Program: A Real-Life Multidisciplinary Circuit

Outpatient parenteral antimicrobial therapy (OPAT) programs encompass a range of healthcare processes aiming to treat infections at home, with the preferential use of the intravenous route. Although several barriers arise during the implementation of OPAT circuits, recent cumulative data have supported the effectiveness of these programs, demonstrating their application in a safe and cost-effective manner. Given that OPAT is evolving towards treating patients with higher complexity, a multidisciplinary team including physicians, pharmacists, and nursing staff should lead the program. The professionals involved require previous experience in infectious diseases treatment as well as in outpatient healthcare and self-administration. As we describe here, clinical pharmacists exert a key role in OPAT multidisciplinary teams. Their intervention is essential to optimize antimicrobial prescriptions through their participation in stewardship programs as well as to closely follow patients from a pharmacotherapeutic perspective. Moreover, pharmacists provide specialized counseling on antimicrobial treatment technical compounding. In fact, OPAT elaboration in sterile environments and pharmacy department clean rooms increases OPAT stability and safety, enhancing the quality of the program. In summary, building multidisciplinary teams with the involvement of clinical pharmacists improves the management of home-treated infections, promoting a safe self-administration and increasing OPAT patients’ quality of life.

Stability of Antimicrobials in Elastomeric Pumps: A Systematic Review

Outpatient parenteral antimicrobial therapy (OPAThttp) programs have become an important healthcare tool around the world. Portable elastomeric infusion pumps are functional devices for ambulatory delivery of antimicrobial drugs, and their stability is an essential point to guarantee an appropriate infusion administration. We conducted a systematic review to provide a synthesis and a critical evaluation of the current evidence regarding antimicrobial stability in elastomeric pumps. Data sources were PubMed, EMBASE, and Web of Sciences. The review protocol was registered on the Center for Open Science, and it was carried out following the PRISMA guidelines. Studies were eligible if the aim was the evaluation of the physicochemical stability of an antimicrobial agent stored in an elastomeric device. Of the 613 papers identified, 33 met the inclusion criteria. The most studied group of antimicrobials was penicillins, followed by cephalosporins and carbapenems. In general, the stability results of the antimicrobials that have been studied in more than one article agree with each other, with the exception of ampicillin, flucloxacillin, and ceftazidime. The antibiotics that displayed a longer stability were glycopeptides and clindamycin. Regarding the stability of antifungals and antivirals, only caspofungin, voriconazole, and ganciclovir have been investigated. The information provided in this article should be considered in patient treatments within the OPAT setting. Further stability studies are needed to confirm the appropriate use of the antimicrobials included in this program to ensure optimal patient outcomes.

Gram-negative bacteria as a cause of mediastinitis after cardiac surgery

PURPOSE OF REVIEW

Poststernotomy mediastinitis (PSM) remains a serious infection and is significantly associated with high morbidity, short-term and long-term mortality. Gram-negative bacteria (GNB) are an underestimated cause of PSM, and there is little information on the risk factors, prevention, diagnosis and management of GNB PSM.

RECENT FINDINGS

The pathogenesis of PSM is the result of a complex and multifactorial interplay between intraoperative wound contamination, host-related and surgical host factors but GNB are probably mostly translocated from other host site infections. GNB are frequent cause of PSM (18-38% of cases) and GNB PSM have shown to more frequently polymicrobial (20-44%). GNG PSM has shown to occur earlier than Gram-positive PSM. Early diagnosis is crucial to successful treatment. The management of PSM needs a combination of culture-directed antimicrobial therapy and an early extensive surgical debridement with either immediate or delayed closure of the sternal space. Antibiotic treatment choice and duration should be based on clinical evaluation, evolution of inflammatory markers, microbiological tests and imaging studies. Mortality has shown to be significantly higher with GNB PSM compared with other causes and the inappropriateness of initial antibiotic therapy may explain the worse outcome of GNB PSM.

SUMMARY

GNB PSM is usually undervalued in the setting of PSM and have shown to be a frequent cause of inappropriate treatment with adverse prognostic potential. There is a need for efforts to improve knowledge to prevent and adequately treat GNB PSM.

Liquid chromatographic method to follow-up ceftazidime and pyridine in portable elastomeric infusion pumps over 24 h

Portable infusion pumps are an interesting solution to continue outpatient parenteral antimicrobial therapy (OPAT) at the patient's home. However, the use of ceftazidime for such applications is challenging in view of its relatively poor stability in solution. In this study, elastomeric infusion pumps with 6 or 7 g of ceftazidime were deflated over 24 h in an oven at 33°C while ceftazidime and its degradation product, pyridine, were regularly monitored. Hereto, a fast and sensitive liquid chromatographic (LC) method has been developed using a Kinetex^® C18 (150 × 3 mm, 2.6 μm) column with gradient elution. Ammonium formate 20 mM and acetonitrile (ACN) were mixed in a ratio of 98:2 v/v for mobile phase A and 85:15 v/v for mobile phase B. Both were adjusted to pH 4.5 with formic acid. The flow rate was set at 0.4 mL/min. The solution with a starting dose of 6 g ceftazidime was found to be degraded 10% after an average of 19 h 11 min so that an administration of 6 g to the patient was not reached. For the solution with a starting dose of 7 g of ceftazidime, 10% degradation was observed after an average of 18 h 42 min. However, by starting from a higher dose, an average of 6.56 g of ceftazidime could be administered over 24 h. In addition, 1.0% of pyridine versus ceftazidime pentahydrate with sodium carbonate (=mixture for injection) was formed over 24 h.

Beta-Lactams Dosing in Critically Ill Patients with Gram-Negative Bacterial Infections: A PK/PD Approach

Beta-lactam antibiotics are often the backbone of treatment for Gram-negative infections in the critically ill. Beta-lactams exhibit time-dependent killing, and their efficacy depends on the percentage of dosing interval that the concentration remains above the minimum inhibitory concentration. The Gram-negative resistance rates of pathogens are increasing in the intensive care unit (ICU), and critically ill patients often possess physiology that makes dosing more challenging. The volume of distribution is usually increased, and drug clearance is variable. Augmented renal clearance and hypermetabolic states increase the clearance of beta-lactams, while acute kidney injury reduces the clearance. To overcome the factors affecting ICU patients and decreasing susceptibilities, dosing strategies involving higher doses, and extended or continuous infusions may be required. In this review, we specifically examined pharmacokinetic models in ICU patients, to determine the desired beta-lactam regimens for clinical breakpoints of Enterobacterales and Pseudomonas aeruginosa, as determined by the European Committee on Antimicrobial Susceptibility Testing. The beta-lactams evaluated included penicillins, cephalosporins, carbapenems, and monobactams. We found that when treating less-susceptible pathogens, especially P. aeruginosa, continuous infusions are frequently needed to achieve the desired pharmacokinetic/pharmacodynamic targets. More studies are needed to determine optimal dosing strategies in the novel beta-lactams.

Effects of Incubation Time and Inoculation Level on the Stabilities of Bacteriostatic and Bactericidal Antibiotics against Salmonella Typhimurium

This study was designed to evaluate the stability of chloramphenicol, erythromycin, tetracycline, cephalothin, ciprofloxacin, and tobramycin against antibiotic-sensitive Salmonella Typhimurium (ASST) and antibiotic-resistant S. Typhimurium (ARST) during the broth microdilution assay. The antimicrobial activity in association with antibiotic stability was measured by using antibiotic susceptibility, time-delayed inoculation, time-extended incubation, and inoculum effect assays. The loss of the antimicrobial activity of cephalothin against ASST exposed to 1 MIC was observed for the 10 h delayed inoculation. The antimicrobial activities of tetracycline and ciprofloxacin against ASST and ARST exposed to ½ MIC were significantly decreased after the 10 h delayed inoculation. All antibiotics used in this study, except for ciprofloxacin, showed the considerable losses of antimicrobial activities against ASST and ARST after 40 h of incubation at 37 °C when compared to the 20 h of incubation during AST. Compared to the standard inoculum level (6 log CFU/mL), the MIC0.1 values of bactericidal antibiotics, ciprofloxacin and tobramycin against ASST were increased by more than 4-fold at the high inoculum level of 9 log CFU/mL. This would provide practical information for better understanding the clinical efficacy of the currently used antibiotics by considering the antibiotic stability during incubation time at different inoculum levels.

Stability and Compatibility Aspects of Drugs: The Case of Selected Cephalosporins

Intravenous drug incompatibilities are a common cause of medical errors, contributing to ineffective therapy and even life-threatening events. The co-administration of drugs must always be supported by studies confirming compatibility and thus guarantee the therapy's safety. Particular attention should be paid to the possible incompatibilities or degradation of intravenous cephalosporins in different infusion regimens since the administration of drugs with inadequate quality may cause treatment failure. Therefore, an appropriate stability test should be performed. The study aimed to present various aspects of the stability and compatibility of five cephalosporins: cefepime (CFE), cefuroxime (CFU), ceftriaxone (CFX), ceftazidime (CFZ), and cefazoline (CFL). The degradation studies in parenteral infusion fluids and PN admixtures were conducted for CFE and CFU. The interactions between CFX or CFZ and PN admixtures, as well as the compatibility of CFL with five commercial parenteral nutrition (PN) admixtures, were investigated. The content of CFX and CFZ in PN admixture after 24 h was >90%. CFL administered simultaneously with PN admixture by the same infusion set using Y-site was compatible only with Nutriflex Lipid Special. CFE and CFU were stable in all tested infusion fluids for a minimum of 48 h and decomposed in PN admixtures during storage.

Outpatient therapy with piperacillin/tazobactam using elastomeric pumps in patients with Pseudomonas aeruginosa infection

The aim of this study was to evaluate the efficacy and safety of outpatient antimicrobial therapy with piperacillin-tazobactam in continuous infusion using elastomeric pumps and to evaluate the economic impact compared with conventional hospital treatment in patients with Pseudomonas aeruginosa (PA) infections. This is an observational study. Patients with PA infection treated with continuous piperacillin-tazobactam infusion using elastomeric pumps in our hospital between January 2015 and December 2017 were included. Primary outcomes were mortality during antibiotic treatment and mortality at 30 days. Secondary outcomes were reinfection or relapse at 30 days and clinical cure rate. The cost of each episode was compared with theoretical cost of the same treatment using conventional hospitalization. 35 patients were included. One patient (2.9%) died during the treatment. Overall 30-day mortality was 5.7%. No death was related to infection by PA. One patient (2.9%) had a reinfection at 30 days. Cure was achieved in 93% of patients at the end of treatment. There were no severe complications related to elastomeric pumps. Treatment cost with outpatient antimicrobial therapy was 67% lower than theoretical cost with conventional hospital treatment. Oupatient antimicrobial therapy with piperacillin-tazobactam in continuous infusion using elastomeric pumps in patients with PA infections is safe and effective with lower costs.

Home intravenous antibiotherapy and the proper use of elastomeric pumps: Systematic review of the literature and proposals for improved use

Over several decades, the economic situation and consideration of patient quality of life have been responsible for increased outpatient treatment. It is in this context that outpatient antimicrobial treatment (OPAT) has rapidly developed. The availability of elastomeric infusion pumps has permitted prolonged or continuous antibiotic administration by dint of a mechanical device necessitating neither gravity nor a source of electricity. In numerous situations, its utilization optimizes administration of time-dependent antibiotics while freeing the patient from the constraints associated with infusion by gravity, volumetric pump or electrical syringe pump and, more often than not, limiting the number of nurse interventions to one or two a day. That much said, the installation of these pumps, which is not systematically justified, entails markedly increased OPAT costs and is liable to expose the patient to a risk of therapeutic failure or adverse effects due to the instability of the molecules utilized in a non-controlled environment, instability that necessitates close monitoring of their use. More precisely, a prescriber must take into consideration the stability parameters of each molecule (infusion duration, concentration following dilution, nature of the diluent and pump temperature). The objective of this work is to evaluate the different means of utilization of elastomeric infusion pumps in intravenous antibiotic administration outside of hospital. Following a review of the literature, we will present a tool for optimized antibiotic prescription, in a town setting by means of an infusion device.

Stability of antimicrobial agents in an elastomeric infusion pump used for outpatient parenteral antimicrobial therapy

OBJECTIVES

The long-term stability of antimicrobials dissolved in infusion solution is necessary to establish and spread the outpatient parenteral antimicrobial therapy (OPAT). In this study, we evaluated the stability of antimicrobial agents dissolved in infusion solutions.

METHODS

The antimicrobial agents were dissolved in infusion solutions and kept at 25 °C and 31.1 °C for 24 h or 4 °C for 10 days in a polypropylene tube or an elastomeric infusion pump. The stability was measured by high-performance liquid chromatography.

RESULTS AND CONCLUSION

The residual ratio of cefazolin (CEZ), cefmetazole (CMZ), piperacillin (PIPC), and tazobactam (TAZ) at 31.1 °C for 24 h was as follows: 95.7 ± 3.0%, 94.8 ± 0.9%, 102.6 ± 1.8%, and 103.9 ± 3.6% in saline, respectively; 94.7 ± 3.0%, 94.3 ± 1.5%, 106.1 ± 3.0%, and 107.3 ± 2.4% in 5% dextrose solution, respectively. The residual ratio of these antimicrobials at 4 °C for 10 days was maintained above 90% in both saline and 5% dextrose solution. The residual ratio of all the above antimicrobials in an elastomeric infusion pump at 31.1 °C for 24 h was equivalent to that in the polypropylene tube. On the other hand, doripenem and meropenem were not stable in any infusion solution at 31.1 °C. CEZ, CMZ, and PIPC/TAZ dissolved in saline or 5% dextrose solution can be used in OPAT with continuous infusion pumps.

Antimicrobial Stewardship: From Bedside to Theory. Thirteen Examples of Old and More Recent Strategies from Everyday Clinical Practice

“Antimicrobial stewardship” is a strategy that promotes the responsible use of antimicrobials. The objective of this paper is to focus on consolidated and more recent improvements in clinical strategies that should be adopted in hospitalized patients to ameliorate their infectious diseases’ outcome and to reduce the antibiotic resistance risk through judicious use of antibiotics. We present 13 common clinical scenarios, the respective suggested interventions and the explanations of the supporting evidence, in order to help clinicians in their decision-making process. Strategies including the choice of antibiotic and dose optimization, antibiotic spectrum narrowing (de-escalation), shortening of duration, shift to oral route or outpatient parenteral antibiotic (including elastomeric pumps), and biomarkers are described and discussed.

Ampicillin and Ceftriaxone Solution Stability at Different Temperatures in Outpatient Parenteral Antimicrobial Therapy

The inclusion of ampicillin-containing regimens in outpatient parenteral antimicrobial therapy programs (OPAT) depends upon solution stability under conditions similar to those experienced in these programs. Lack of this information could hinder the inclusion in OPAT of patients suffering from Enterococcus faecalis infective endocarditis treated with ampicillin plus ceftriaxone. The purpose of this study is to determine the stability of ampicillin and ampicillin plus ceftriaxone solutions in a simulated outpatient setting conditions. Solutions of ampicillin 24 g/liter and ampicillin 24 g/liter combined with ceftriaxone 8 g/liter were stored at 25°C ± 2°C, 30°C ± 2°C and 37°C ± 2°C for 48 h. Chemical and physical stability were evaluated at 20, 24, 30, and 48 h after manufacturing. The solutions were considered stable if the percentage of intact drug was ≥90% and color and clearness remained unchanged. After 24 h of storage at a controlled temperature, ampicillin solution in 0.9% sodium chloride was found to be stable for 30 h at 25 and 30°C and for 24 h at 37°C. In the ampicillin plus ceftriaxone combined solution, both antibiotics were found to be stable after 30 h of storage at 25 and 30°C, but at 37°C, the stability criterion was not met at any time point. Our study offers solid evidence demonstrating that the concentrations of both drugs at two of the tested temperatures (25°C and 30°C) were stable for up to 30 h. Therefore, both ampicillin alone and ampicillin plus ceftriaxone solutions would be appropriate candidates for inclusion in OPAT programs.

Human Factors approaches to evaluating outpatient parenteral antimicrobial therapy services: A systematic review

BACKGROUND

The expansion in terms of available treatment options and models of care has led to a growing global momentum for outpatient antimicrobial therapy (OPAT) services. A systematic review was undertaken to explore Human Factors aspects relating to OPAT service delivery and to evaluate whether OPAT is amenable to description using the Systems Engineering Initiative for Patient Safety (SEIPS 2.0) model.

METHOD

Following a preliminary search, a search string was applied to four databases, including Medline, Cumulative Index of Nursing and Allied Health Literature, International Pharmaceutical Abstracts and PsychINFO. Inclusion criteria ensured only articles published after the year 2000 and written in English were accepted. The methodological quality of studies was assessed by three reviewers. Narrative synthesis was performed to uncover the key interactions between work system entities which underpin OPAT processes and outcomes as described using the SEIPS 2.0 model.

RESULTS

A total of twenty-seven studies were deemed eligible for the final review. Of these, most described sample populations representative of the population under study, while duration of the studies varied from a few months to years. Some studies evaluated a single model of care whilst others evaluated all three currently available models. The breadth and scope of the studies included enabled extraction of rich Human Factors data describing barriers and enablers to service provision.

CONCLUSION

OPAT is a service which offers significant benefits to both patients and care providers. These benefits include patient satisfaction and wellbeing, as well as financial performance. OPAT is a complex sociotechnical system, and a systems approach may offer the opportunity to enhance system design, maximising system performance. This review demonstrates that the service can be better understood using the SEIPS 2.0 model to identify key work system interactions that support performance.

Therapy of Staphylococcus aureus bacteremia: Evidences and challenges

Staphylococcus aureus bacteremia (SAB) is still a daily challenge for clinicians. Despite all efforts, the associated mortality and morbidity has not significantly improved in the last 20 years. The available evidence suggests that adherence to some quality-of-care indicators with regard to clinical management is important in improving the outcome of patients, but it is lower than desired in many hospitals; as such, management of patients with SAB by infectious diseases specialists has been demonstrated to contribute in the reduction of the mortality rate of these patients. In this article, the most relevant clinical studies published over the last few years evaluating the efficacy and safety of alternative drugs for the treatment of SAB are reviewed. However, classic drugs are still used in a high proportion of patients because the promising results obtained from in vivo and in vivo studies with these alternative drugs have not translated as frequently as expected into evident superiority in clinical studies. Nevertheless, some data suggest that certain alternatives may offer advantages in specific situations. Overall, an individualised and expert approach is needed in order to decide the best treatment according to the source, severity, complications, patients' features and microbiological data.

Ceftolozane-tazobactam in an elastomeric infusion device for ambulatory care: an in vitro stability study

Objectives

Published in vitro stability data for ceftolozane-tazobactam supports intermittent short duration infusions. This method of delivery is not feasible for many outpatient antimicrobial therapy services that provide only one or two visits per day. This study aimed to assess time, temperature and concentration-dependent stability of ceftolozane-tazobactam in an elastomeric infusion device for continuous infusion across clinically relevant ranges encountered in outpatient antimicrobial therapy.

Methods

Ceftolozane-tazobactam was prepared to achieve initial concentrations representing total daily doses for 'renal', 'standard' and 'high' dose schedules in elastomeric infusion devices with a volume of 240 mL. Infusion devices incubated at room and body temperature were serially sampled over 48 hours. Refrigerated infusion devices were sampled over 10 days. Concentrations of ceftolozane and tazobactam were separately quantified using a validated ultra-high performance liquid chromatography-photodiode array method.

Results

The greatest loss of ceftolozane occurred at 37°C, however, stability remained above 90% at 24 hours. Tazobactam was more stable than ceftolozane under these conditions. There was minimal loss at 4°C for either component over 7 days.

Conclusions

Ceftolozane-tazobactam is suitable for ambulatory care delivered as a continuous infusion via an elastomeric infusion device.

Efficacy and safety of continuous infusions with elastomeric pumps for outpatient parenteral antimicrobial therapy (OPAT): an observational study

Objectives

This study aimed to evaluate the efficacy and safety of continuous antimicrobial infusion using elastomeric pumps in an outpatient setting, while simultaneously documenting circulating antibiotic concentration exposure achieved with this mode of administration.

Methods

Clinical outcomes, adverse events and antibiotic plasma concentrations were recorded for all patients treated by continuous infusion with elastomeric pumps at the outpatient parenteral antimicrobial therapy (OPAT) unit of the University Hospital of Lausanne between December 2013 and January 2017. The study was registered under ClinicalTrials.gov identifier NCT03221140.

Results

One hundred and fifty outpatients were treated by continuous intravenous infusions using flucloxacillin (70 patients), cefepime (36), vancomycin (32) and piperacillin/tazobactam (12). The calculated free fractions of each antibiotic were above the epidemiological cut-off values for resistance (ECOFF) of the treated microorganisms in 92% of measurements. Cure was achieved in 143 patients (95%) 3 months after the end of treatment. Four patients needed unexpected readmission and three had a relapse. In none of the patients with unsuccessful treatment was the ratio of free antibiotic plasma concentration/ECOFF <1. Sixteen patients (11%) had an adverse event, none of them being of severity grade 4 or 5.

Conclusions

Continuous infusions of flucloxacillin, cefepime, vancomycin and piperacillin/tazobactam using elastomeric pumps seem to be an effective and safe approach to treat outpatients. The number of treatment successes was very high and adverse events occurred at a similar rate as reported by other OPAT centres. The measured antibiotic plasma concentrations confirmed adequate drug concentration exposure for the vast majority of patients.

Overcoming stability challenges during continuous intravenous administration of high-dose amoxicillin using portable elastomeric pumps

While treatment of serious infectious diseases may require high-dose amoxicillin, continuous infusion may be limited by lack of knowledge regarding the chemical stability of the drug. Therefore, we have performed a comprehensive study so as to determine the chemical stability of high-dose amoxicillin solutions conducive to safe and effective continuous intravenous administration using portable elastomeric pumps. First, amoxicillin solubility in water was assessed within the range of 25 to 300 mg/mL. Then, amoxicillin solutions were prepared at different concentrations (25, 50, 125, 250 mg/mL) and stored in different conditions (5±2°C, 25±1°C, 30±1°C and 37±1°C) to investigate the influence of concentration and temperature on the chemical stability of amoxicillin. Finally, its stability was assessed under optimized conditions using a fully validated HPLC-UV stability-indicating method. Degradation products of amoxicillin were investigated by accurate mass determination using high-resolution mass spectrometry. Amoxicillin displayed limited water solubility requiring reconstitution at concentrations below or equal to 150 mg/mL. Amoxicillin degradation were time, temperature as well as concentration-dependent, resulting in short-term stability, in particular at high concentrations. Four degradation products of amoxicillin have been identified. Among them, amoxicilloic acid and diketopiperazine amoxicillin are at risk of allergic reaction and may accumulate in the patient. Optimized conditions allowing for continuous infusion of high-dose amoxicillin has been determined: amoxicillin should be reconstituted at 25 mg/mL and stored up to 12 hours at room temperature (22 ± 4°C) or up to 24 hours between 4 and 8°C.

Systematic review of stability data pertaining to selected antibiotics used for extended infusions in outpatient parenteral antimicrobial therapy (OPAT) at standard room temperature and in warmer climates

Aim

To determine if there are sufficient stability data to confirm appropriate prescribing of antibiotics commonly used in outpatient parenteral antimicrobial therapy (OPAT) in warmer climates.

Data sources

Four databases were systematically searched using the terms 'beta-lactams', or 'antibiotics', or 'anti-bacterial agents' and 'drug stability' or drug storage' for studies specific to drug stability published between 1966 and February 2018.

Study selection

The search strategy initially identified 2879 potential articles. After title and abstract review, the full-texts of 137 potential articles were assessed, with 46 articles matching the inclusion and exclusion criteria included in this review.

Results

A large volume of stability data is available for the selected drugs. Stability data at temperatures higher than 25°C were available for several of the medications, however few drugs demonstrated stability in warmer climates of 34°C or higher. Only buffered benzylpenicillin, cefoxitin and buffered flucloxacillin were found to have stability data supporting OPAT in warmer climates. Sequential data, profiling the drug for an extended period in solution under refrigeration prior to the run-out period at the higher temperatures, are also lacking.

Limitations

This study was limited by including only peer reviewed articles. There may be further grey literature supporting the stability of some of the drugs mentioned.

Conclusion

There are insufficient stability data of antibiotic use in warmer climates. Studies to verify the stability and appropriate use of many antibiotics used in OPAT at standard room temperature and in warmer climates are urgently required. Several drugs in current use in the OPAT settings are lacking stability data.

Implications

Further research in this field is needed to develop structured evidence-based guidelines. Results of this review should be further compared with observed patient outcomes in current clinical practice.

Hazards from physical attributes of the home environment among patients on outpatient parenteral antimicrobial therapy

BACKGROUND

Outpatient parenteral antimicrobial therapy (OPAT) requires that patients and their caregivers administer antimicrobial medications in the home via venous catheters. Hazards from physical attributes of the home environment may impede safe performance of OPAT tasks.

METHODS

We performed a qualitative study, including semistructured telephone interviews and contextual inquiries, of patients performing OPAT tasks inside the home. Eligible participants were discharged from 2 academic medical centers in Baltimore, Maryland, on OPAT. We coded interview transcripts and contextual inquiry forms based on a model of healthcare work systems.

RESULTS

Twenty-nine patients underwent semistructured telephone interviews, and 14 patients underwent contextual inquiry. We identified hazards including bathing, animal or pets, extremes in temperature, household clutter, indoor soil and food exposures, outdoor soil, and travel. Patients often developed strategies to mitigate these hazards.

DISCUSSION

Multiple hazards related to the home environment could have led to harm, and in the absence of specific guidance, patients developed strategies to mitigate these hazards.

CONCLUSIONS

Educational interventions to improve OPAT should incorporate an understanding of hazards that may occur in the home environment.

Outpatient parenteral antimicrobial therapy and antibiotic stewardship: opponents or teammates?

PURPOSE

This narrative review aims to describe barriers of outpatient parenteral antimicrobial therapy at home (OPAT), potentially compromising general standards of antibiotic stewardship (ABS) and facilitators of OPAT for ABS.

METHODS

After a literature review, five authors determined the barriers and facilitators to discuss in this review.

RESULTS

Sixty-six publications were included in the narrative review and seven barriers and five facilitators are discussed in this article. The impracticability of multiple daily dosing during OPAT, the impact of real-life temperature variations, deviations of the infusion rates of elastomeric devices, access to prolonged intravenous antibiotic therapy, not administering loading doses before the initiation of extended or continuous infusions and the transmural nature of care associated with OPAT, can lead to deviations of recommended treatment regimens and sub-optimal clinical and laboratory follow-up, with a risk of inferior clinical outcomes, adverse events, drug-resistance and higher costs. On the other hand, OPAT provides access to treatments with intravenous antibiotics and simultaneously avoids prolonged hospitalization.

CONCLUSION

Implementing ABS guidelines in OPAT programs, e.g., by using a multidisciplinary team approach and facility-specific protocols for OPAT with patient selection criteria and instructions for selection, storage, preparation and administration of antibiotics, can improve appropriate antibiotic use. Additionally, further research should examine the effectiveness of these interventions on outcomes of OPAT.

Assessment of the stability of citrate-buffered flucloxacillin for injection when stored in two commercially available ambulatory elastomeric devices: INfusor LV (Baxter) and Accufuser (Woo Young Medical): a study compliant with the NHS Yellow Cover Document (YCD) requirements

Objectives

To investigate the effect of pH and buffers on the degradation rate of flucloxacillin and to determine if flucloxacillin can be stabilised using a buffered diluent for up to 14 days when stored at 2°C–8°C including a 24-hour infusion period at 32°C in two elastomeric devices (Accufuser and INfusor LV) filled to 240 mL. Testing as per the NHS Pharmaceutical Quality Assurance Committee Yellow Cover Document (YCD) requirements.

Methods

A validated stability indicating high-performance liquid chromatography method was used for assessing the stability of flucloxacillin diluted in 0.3% w/v citrate-buffered saline pH 7.0 when stored at 2°C–8°C in two ambulatory devices (Accufuser and INfusor LV). Flucloxacillin at 10 and 50 mg/mL diluted in 0.3% w/v citrate-buffered saline pH 7.0 to a final volume of 240 mL and stored at 2°C–8°C, including 24 hours at 32°C, was tested from two batches in replicate (n=3) at five time points for up to 14 days according to the requirements of the YCD.

Results

Greater than 95% of the zero-time concentration of flucloxacillin at 10 and 50 mg/mL remained when stored at 2°C–8°C after 14 days including 24 hours at 32°C in both Accufuser and INfusor LV devices.

Conclusions

Flucloxacillin sodium stability was improved, and complied with UK national standards, by using a diluent of 0.3% w/v citrate-buffered saline pH 7 in both Accufuser and INfusor LV ambulatory devices when filled to 240 mL. The data support assigning a shelf-life of up to 14 days (13 days stored at 2°C–8°C and 24 hours at 32°C). Flucloxacillin may now be used appropriately as a continuous 24-hour infusion in outpatient parenteral antimicrobial therapy services, providing further opportunity to avoid or shorten patient hospital stays, as well as support ideal antimicrobial stewardship principles.

Adequate plasma drug concentrations suggest that amoxicillin can be administered by continuous infusion using elastomeric pumps

Background

Elastomeric pumps can be useful for the administration of antibiotics in the outpatient setting.

Objectives

To determine amoxicillin degradation in elastomeric pumps, as well as the effectiveness of amoxicillin treatment administered by elastomeric pumps.

Methods

Antibiotic degradation was measured in elastomeric pumps filled with 6 g of amoxicillin in 240 mL of NaCl 0.9% by drawing samples at 12 h intervals when stored in the fridge for 48 h and when worn around the waist for 24 h. Subsequently nine patients were treated with continuous infusions of 8 or 12 g of amoxicillin per day. Plasma amoxicillin concentrations were measured on each visit to the outpatient parenteral antibiotic therapy unit. Clinical outcome was verified 3 months after the end of treatment.

Results

Amoxicillin degradation in elastomeric pumps reached 10% after 48 h in the fridge and an additional 30% when worn around the waist for 24 h. Mean plasma drug concentrations achieved with 12 g of amoxicillin per day were 18.5 mg/L (95% CI 13.5-23.5), which is largely above the MIC of amoxicillin-susceptible bacteria. Nine patients treated for various complicated infections were cured and had no unexpected adverse effects.

Conclusions

Adequate plasma drug concentrations and favourable clinical outcomes suggest that amoxicillin can be administered by continuous infusion using elastomeric pumps. This treatment modality does not fulfil formal requirements regarding pharmaceutical stability, but the resulting safety impact in patients is probably limited. Therapeutic drug monitoring and a close clinical follow-up are recommended if this route of administration is chosen.

Stability of Cefazolin in Polyisoprene Elastomeric Infusion Devices

PURPOSE

The aim was to investigate the stability of cefazolin in elastomeric infusion devices.

METHODS

Elastomeric devices (Infusor LV) that contain cefazolin (3 g/240 mL and 6 g/240 mL) were prepared and stored at 4°C for 72 hours and then at 35°C for 12 hours, followed by 25°C for 12 hours. An aliquot was withdrawn at predefined time points and analyzed for the concentration of cefazolin. Samples were also assessed for changes in pH, solution color, and particle content.

FINDINGS

Cefazolin retained acceptable chemical and physical stability over the studied storage period and conditions.

IMPLICATIONS

These findings will allow the administration of cefazolin by the Infusor LV elastomeric device in the outpatient and remote settings.