Subcutaneous suppressive antibiotic therapy for bone and joint infections: safety and outcome in a cohort of 10 patients

Dalbavancin as suppressive therapy for implant-related infections: a case series with therapeutic drug monitoring and review of the literature

Implant-related infections may need suppressive antibiotic therapy (SAT). We describe a SAT strategy using dalbavancin with therapeutic drug monitoring (TDM). This is a retrospective bicentric study of patients with implant-related infection who received dalbavancin SAT between January 2021 and September 2023. Fifteen patients were included. Median number of injections was 4 (IQR: 2-7). Median time between two reinjections was 57 days (IQR 28-82). Dalbavancin plasma concentrations were above 4 mg/L for 97.9% of dosages (93/95) and above 8 mg/L for 85% (81/95). These results support the use of dalbavancin SAT for implant-related infections.

Safety of subcutaneous versus intravenous ceftriaxone administration in older patients: A retrospective study

BACKGROUND

Antibiotics play a central role in infection management. In older patients, antibiotics are frequently administered subcutaneously. Ceftriaxone pharmacokinetics after subcutaneous administration is well documented, but little data are available on its safety.

METHODS

We compared the occurrence of adverse events associated with ceftriaxone administered subcutaneously versus intravenously in ≥75-year-old patients. We used data from a single-center, retrospective, clinical-administrative database to compare the occurrence of adverse events at day 14 and outcome at day 21 in older patients who received ceftriaxone via the subcutaneous route or the intravenous route at Rennes University Hospital, France, from May 2020 to February 2023.

RESULTS

The subcutaneous and intravenous groups included 402 and 3387 patients, respectively. Patients in the subcutaneous group were older and more likely to receive palliative care. At least one adverse event was reported for 18% and 40% of patients in the subcutaneous and intravenous group, respectively (RR = 2.21). Mortality at day 21 was higher in the subcutaneous route group, which could be linked to between-group differences in clinical and demographic features.

CONCLUSIONS

In ≥75-year-old patients, ceftriaxone administered by the subcutaneous route is associated with less-adverse events than by the intravenous route. The subcutaneous route, which is easier to use, has a place in infection management in geriatric settings.

The Subcutaneous Administration of Beta-Lactams: A Case Report and Literary Review-To Do Small Things in a Great Way

The subcutaneous (s.c.) route is a commonly used method for delivering various drugs, although its application in the administration of antibiotics is relatively uncommon. In this case, we report a successful treatment of nosocomial pneumonia using piperacillin/tazobactam via continuous subcutaneous administration. Furthermore, this article provides an overview of the current literature regarding the s.c. administration of beta-lactam antibiotics. Based on our analysis, we identified only 15 studies that described the s.c. use of beta-lactam antibiotics in human subjects. Among these studies, cephalosporins were the most extensively investigated antibiotic class, with 10 available studies. According to the study findings, all three antibiotic classes (cephalosporins, penicillins, and carbapenems) demonstrated a similar pharmacokinetic profile when administered via the subcutaneous route. The subcutaneous route appears to be associated with a lower peak serum concentration (Cmax) but a comparable minimum blood concentration (Cmin) and an extended half-life (t1/2) when compared to conventional routes of antibiotic administration. Further research is necessary to determine whether subcutaneously administered beta-lactam antibiotics in human subjects achieve pharmacodynamic targets and demonstrate clinical efficacy.

Effectiveness of Subcutaneous Administration of Antibiotics to Control Infections in Elder Palliative Patients: A Systematic Review

Background: Infections are common in patients with advanced illnesses for whom the intravenous or oral route is not possible. The subcutaneous administration of antibiotics is a promising alternative, but there is not enough theoretical support for its use. This study aims to explore the effectiveness and safety of subcutaneous antibiotic therapy in the context of palliative care in elderly patients. Methods: A systematic review was conducted using PubMed and Embase, without time or language limits. Seven articles were selected on the effectiveness of subcutaneous antibiotic therapy in adult patients with chronic progressive diseases. The quality of the articles was assessed with the Newcastle Ottawa Scale and relevant data was extracted using a selection capture file. Results: Seven quasi-experimental studies evaluated 865 elderly patients with advanced diseases, comorbidities, and infections (ie, urinary tract, respiratory system, and bone joint) who received subcutaneous antibiotic therapy (ie, Ceftriaxone, Ertapenem, and Teicoplanin). The pooled success rate of subcutaneous antibiotics for the 7 studies was 71%, the therapy failure rate was 22%, its withdrawal mean was 8%, and the mean mortality rate was 7%. The studies were of low quality and were heterogeneous in the types of infections, types of antibiotics, time of follow-up, and outcomes assessed. Conclusions: Pilot studies have found a limited number of antibiotics that can be safely used to treat specific infections. Nevertheless, the data isn´t robust enough to recommend their use.

Dalbavancin as suppressive antibiotic therapy in patients with prosthetic infections: efficacy and safety

Suppressive antibiotic therapy (SAT) is a strategy to alleviate symptoms and/or to reduce the progression of an infection when other treatment options cannot be used. Dalbavancin, due to its prolonged half-life, enables (bi) weekly dosing. Here, we report our multicenter real-life clinical experience with dalbavancin used as SAT in patients with prosthetic joint or vascular infections. Medical records of all adult patients with documented vascular or orthopedic chronic prosthetic infections, who received dalbavancin as SAT between 2016 and 2018 from four Spanish hospitals were reviewed for inclusion. Descriptive analysis of demographic characteristics, Charlson Comorbidity index, Barthel index, isolated pathogens and indication, concomitant antibiotic use, adverse events, and clinical outcome of SAT were performed. Eight patients were eligible for inclusion, where six patients had prosthetic vascular infections (aortic valve) and two patients had knee prosthetic joint infections. The most common pathogens were methicillin-susceptible Staphylococcus aureus and Enterococcus faecium. All patients had a history of prior antibiotic treatment for the prosthetic infection [median duration of antibiotic days 125 days (IQR, 28-203 days)]. The median number of dalbavancin doses was 29 (IQR, 9-61) and concomitant antibiotic use (n = 5, 62.5%). Clinical success was reported in 75% (n = 6) of patients. Adverse events were reported in two patients (mild renal and hepatic impairment). The median estimated cost savings due to the avoided hospital days was €60185 (IQR, 19,916-94984) per patient. Despite the limitations of our study, this preliminary data provides valuable insight to support further evaluation of dalbavancin for SAT in patients with prosthetic infections in the outpatient setting when alternative treatments are not feasible.

Subcutaneously administered antibiotics: a review

BACKGROUND

Subcutaneous (SC) administration of antibiotics represents an attractive alternative to the intravenous (IV) route.

METHODS

We performed a systematic electronic search of PubMed and the Cochrane Library for all articles published prior to April 2022, using the key terms and MeSH terms 'subcutaneous', 'antibiotic' and the international non-proprietary name of antibiotics.

RESULTS

A total of 30 studies were selected including data on the efficacy and tolerability of antibiotics, and seven studies that were conducted in healthy subjects, for relevant information regarding the safety and tolerability of antibiotics. Comparative studies have shown that efficacy is similar for the SC and IV routes for ceftriaxone, teicoplanin and ertapenem. The SC use of other antibiotics such as ampicillin, ceftazidime, cefepime, piperacillin/tazobactam, metronidazole and fosfomycin has also been described. These results have largely been corroborated by pharmacokinetic/pharmacodynamic analyses, especially for time-dependent antibiotics. Complications of SC treatment are rarely severe, with no reports of bacteraemia or other invasive infection related to this route of administration. Therapeutic drug monitoring has been proposed to adapt the dose and avoid toxicity.

DISCUSSION

The rationale for using SC administration of ceftriaxone, ertapenem and teicoplanin is strong in patients with non-severe infections. It is already commonly practised in some countries, particularly in France. Other antibiotics could be administered subcutaneously, but further studies are needed to validate their use in clinical practice. Further research is needed to safely generalize and optimize this route of administration whenever possible. This would reduce the risk of catheter-related infections and their complications, together with the length of hospital stay.

The efficacy of suppressive antibiotic treatment in patients managed non-operatively for periprosthetic joint infection and a draining sinus

Objectives: Patients with prosthetic joint infections (PJIs) not suitable for curative surgery may benefit from suppressive antibiotic therapy (SAT). However, the usefulness of SAT in cases with a draining sinus has never been investigated. Methods: A multicentre, retrospective observational cohort study was performed in which patients with a PJI and a sinus tract were eligible for inclusion if managed conservatively and if sufficient follow-up data were available (i.e. at least 2 years). SAT was defined as a period of >  6 months of oral antibiotic therapy. Results: SAT was initiated in 63 of 72 (87.5 %) included patients. Implant retention during follow-up was the same in patients receiving SAT vs. no SAT (79.4 % vs. 88.9 %; p = 0 .68). In total, 27 % of patients using SAT experienced side effects. In addition, the occurrence of prosthetic loosening in initially fixed implants, the need for surgical debridement, or the occurrence of bacteremia during follow-up could not be fully prevented with the use of SAT, which still occurred in 42 %, 6.3 %, and 3.2 % of cases, respectively. However, the sinus tract tended to close more often (42 % vs. 13 %; p = 0 .14), and a higher resolution of pain was observed (35 % vs. 14 %; p = 0 .22) in patients receiving SAT. Conclusions: SAT is not able to fully prevent complications in patients with a draining sinus. However, it may be beneficial in a subset of patients, particularly in those with pain or the hindrance of a draining sinus. A future prospective study, including a higher number of patients not receiving SAT, is needed.

Suppressive Antibiotic Treatment in Prosthetic Joint Infections: A Perspective

The treatment of prosthetic joint infections (PJIs) is a complex matter in which surgical, microbiological and pharmacological aspects must be integrated and, above all, placed in the context of each patient to make the best decision. Sometimes it is not possible to offer curative treatment of the infection, and in other cases, the probability that the surgery performed will be successful is considered very low. Therefore, indefinite administration of antibiotics with the intention of "suppressing" the course of the infection becomes useful. For decades, we had little information about suppressive antibiotic treatment (SAT). However, due to the longer life expectancy and increase in orthopaedic surgeries, an increasing number of patients with infected joint prostheses experience complex situations in which SAT should be considered as an alternative. In the last 5 years, several studies attempting to answer the many questions that arise on this issue have been published. The aim of this publication is to review the latest published evidence on SAT.

Risk Scores and Machine Learning to Identify Patients With Acute Periprosthetic Joints Infections That Will Likely Fail Classical Irrigation and Debridement

The most preferred treatment for acute periprosthetic joint infection (PJI) is surgical debridement, antibiotics and retention of the implant (DAIR). The reported success of DAIR varies greatly and depends on a complex interplay of several host-related factors, duration of symptoms, the microorganism(s) causing the infection, its susceptibility to antibiotics and many others. Thus, there is a great clinical need to predict failure of the "classical" DAIR procedure so that this surgical option is offered to those most likely to succeed, but also to identify those patients who may benefit from more intensified antibiotic treatment regimens or new and innovative treatment strategies. In this review article, the current recommendations for DAIR will be discussed, a summary of independent risk factors for DAIR failure will be provided and the advantages and limitations of the clinical use of preoperative risk scores in early acute (post-surgical) and late acute (hematogenous) PJIs will be presented. In addition, the potential of implementing machine learning (artificial intelligence) in identifying patients who are at highest risk for failure of DAIR will be addressed. The ultimate goal is to maximally tailor and individualize treatment strategies and to avoid treatment generalization.

Pharmacokinetic/Pharmacodynamic Dosage Individualization of Suppressive Beta-Lactam Therapy Administered by Subcutaneous Route in Patients With Prosthetic Joint Infection

Suppressive parenteral antibiotic therapy with beta-lactams may be necessary in patients with Gram-negative bone and joint infection (BJI). Subcutaneous drug administration can facilitate this therapy in outpatient setting, but there is limited information about this practice. We have developed an original approach for drug dosing in this context, based on therapeutic drug monitoring (TDM) and pharmacokinetic/pharmacodynamic (PK/PD) principles. The objective of this study was to describe our approach and its first results in a case series. We analyzed data from patients who received suppressive antibiotic therapy by subcutaneous (SC) route with beta-lactams as salvage therapy for prosthetic joint infection (PJI) and had TDM with PK/PD-based dose adjustment. Ten patients (six women and four men with a mean age of 77 years) were included from January 2017 to May 2020. The drugs administered by SC route were ceftazidime (n = 4), ertapenem (n = 4), and ceftriaxone (n = 2). In each patient, PK/PD-guided dosage individualization was performed based on TDM and minimum inhibitory concentration (MIC) measurements. The dose interval could be prolonged from twice daily to thrice weekly in some patients, while preserving the achievement of PK/PD targets. The infection was totally controlled by the strategy in nine out the 10 patients during a median follow-up of 1,035 days (~3 years). No patient acquired carbapenem-resistant Gram-negative bacteria during the follow-up. One patient presented treatment failure with acquired drug resistance under therapy, which could be explained by late MIC determination and insufficient exposure, retrospectively. To conclude, our innovative approach, based on model-based TDM, MIC determination, and individualized PK/PD goals, facilitates, and optimizes suppressive outpatient beta-lactam therapy administered by SC route for PJI. These encouraging results advocate for larger clinical evaluation.

Outpatient Subcutaneous Antimicrobial Therapy (OSCAT) as a Measure to Improve the Quality and Efficiency of Healthcare Delivery for Patients With Serious Bacterial Infections

Since the 1970s, outpatient parenteral antimicrobial therapy (OPAT) has been a viable option for patients who require intravenous antibiotics when hospitalization is not warranted. While the benefits of OPAT as a measure to improve the efficiency of healthcare delivery (i.e., reduced hospital days) and patient satisfaction are well-documented, OPAT is associated with a number of challenges, including line complications and reliance on daily healthcare interactions in some cases at home or in a clinic. To minimize the continued need for intensive healthcare services in the outpatient setting, there is trend toward patients self-administering antibiotics at home without the presence of healthcare workers, after adequate training. In most cases, patients administer the antibiotics through an established intravenous catheter. While this OPAT practice is becoming more accepted as a standard of care, the potential for line complications still exists. Outpatient subcutaneous antimicrobial therapy (OSCAT) has become an increasingly accepted alternative route of administration of antibiotics to IV by French infectious diseases physicians and geriatricians; however, currently, no antibiotics are approved to be administered subcutaneously. Antibiotics with longer half-lives that are completely absorbed and have a favorable local tolerability profile are ideal candidates for OSCAT and have the potential to maximize the quality and efficiency of parenteral antibiotic delivery in the outpatient setting. The increasing development of wearable, on-body subcutaneous delivery systems make OSCAT even more viable as they increase patient independence while avoiding line complications and potentially removing the need for direct healthcare professional observation.

Medical innovations to maintain the function in patients with chronic PJI for whom explantation is not desirable: a pathophysiology-, multidisciplinary-, and experience-based approach

INTRODUCTION

PJI is the most dramatic complication after joint arthroplasty. In patients with chronic infection, prosthesis exchange is in theory the rule. However, this surgical approach is sometimes not desirable especially in elderly patients with multiple comorbidities, as it could be associated with a dramatic loss of function, reduction of the bone stock, fracture, or peroperative death. We propose here to report different approaches that can help to maintain the function in such patients based on a pathophysiology-, multidisciplinary-, and an experience-based approach.

METHODS

We describe the different points that are needed to treat such patients: (i) the multidisciplinary care management; (ii) understanding the mechanism of bacterial persistence; (iii) optimization of the conservative surgical approach; (iv) use of suppressive antimicrobial therapy (SAT); (v) implementation of innovative agents that could be used locally to target the biofilm.

RESULTS

In France, a nation-wide network called CRIOAc has been created and funded by the French Health ministry to manage complex bone and joint infection. Based on the understanding of the complex pathophysiology of PJI, it seems to be feasible to propose conservative surgical treatment such as "debridement antibiotics and implant retention" (with or without soft-tissue coverage) followed by SAT to control the disease progression. Finally, there is a rational for the use of particular agents that have the ability to target the bacteria embedded in biofilm such as bacteriophages and phage lysins.

DISCUSSION

This multistep approach is probably a key determinant to propose innovative management in patients with complex PJI, to improve the outcome.

CONCLUSION

Conservative treatment has a high potential in patients with chronic PJI for whom explantation is not desirable. The next step will be to evaluate such practices in nation-wide clinical trials.

Local Tissue Response to Subcutaneous Administration of Ceftriaxone in an Animal Model

Subcutaneous administration is a novel way to deliver antibiotics for an infection, but intolerability has been reported. Evaluating the local tolerability of subcutaneously administered antibiotics is not standardized. The goal of this study was to develop an animal model to assess the subcutaneous administration of ceftriaxone. Sprague-Dawley rats were given daily subcutaneous injections for 12 days. The back of each animal was divided into 4 quadrants, with injections rotating each day among the quadrants. Ceftriaxone (1,000 mg/kg of body weight daily) was given in different concentrations and durations. Normal saline and potassium chloride solutions (2 meq/2 ml) were used as negative and positive controls, respectively. After the treatment course, skin samples were biopsied, and the local inflammatory response was assessed histologically using a semiquantitative scoring system. The histopathology scores were compared using a Kruskal-Wallis test. Injections with potassium chloride resulted in full-thickness skin necrosis with subcutaneous atrophy that was not seen in the saline-injected animals; inflammation of the muscular panniculus was observed, with various degrees of myocyte injury. Serosanguinous cavity formation in the subcutaneous compartment was observed when ceftriaxone (125 mg/ml) was given as a bolus injection, but the extent of the local tissue response was remarkably reduced when the same ceftriaxone dose was given at a lower concentration (25 mg/ml) over 120 min (P = 0.63, compared to saline controls). At a low concentration, ceftriaxone infusion was found to be well tolerated in this animal tissue necrosis model. If validated, the model could be an instrumental platform to evaluate different pharmaceutical formulations for subcutaneous delivery.

Complications of peripheral venous catheters: The need to propose an alternative route of administration

Use of peripheral venous catheters (PVCs) is very common in hospitals. According to the literature, after a visit to the emergency department >75% of hospitalised patients carry a PVC, among which almost 50% are useless. In this study, the presence and complications of PVCs in an infectious diseases (ID) unit of a French tertiary-care university hospital were monitored. A total of 614 patients were prospectively included over a 6-month period. Among the 614 patients, 509 (82.9%) arrived in the ID unit with a PVC, of which 260 (51.1%) were judged unnecessary and were removed as soon as the patients were examined by the ID team. More than one-half of PVCs were removed within 24 h in the unit (308/509; 60.5%). PVCs were complicated for 65 (12.8%) of the 509 patients, with complications including extravasation, cutaneous necrosis, lymphangitis, phlebitis, tearing off the patient, superficial venous thrombosis and arthritis. We must therefore continue to search for unjustified PVC insertion. Alternatives to the intravenous administration route must be proposed, such as subcutaneous infusion or oral antibiotic therapy.