[Translated article] Retrospective study of home antibiotic infusion therapy using elastomeric infusion pumps

OBJECTIVES

To describe the experience of home antibiotic infusion therapy using elastomeric infusion pumps, administered to patients admitted to the Home Hospitalisation Unit of a tertiary hospital for 3 years and to analyse clinical evolution and mortality.

METHOD

Retrospective observational study. The medical history of the patients included in the study was reviewed. Information was obtained on personal history, antimicrobial therapy received, and clinical evolution. Statistical analysis was performed using SPSS® 19 software.

RESULTS

81 patients were included, 61.7% men, with a mean age of 73.5±17.5 years. The most frequent comorbidities were diabetes mellitus (30.9%) and chronic kidney disease (28.4%). Patients received a mean of 11.9±8.5 days of antibiotic treatment in an elastomeric infusion pump. The main focus of infection was respiratory (27.2%), followed by bacteremia (16%) and skin and soft tissue infections (12.3%). Of the infections, 65.4% were monomicrobial, with Pseudomonas aeruginosa being the main microorganism involved (39.6%). The most commonly used antimicrobial was piperacillin/tazobactam (33.3%). The clinical course was good in 85.2% of the patients, but the mortality rate in the 30 days following the end of treatment was 24.7%. In the univariate analysis, a history of neoplasia in the last 5 years (p=.01) and having received fewer days of antibiotic therapy prior to the start of outpatient antimicrobial therapy in infusion pump (p=.04) were associated with worse clinical outcome. Age over 80 years was associated with better outcome (p=.03). The diagnosis of heart failure was associated with higher mortality (p=.026) and patients from surgical services, with lower mortality (p=.047). In the multivariate analysis, the presence of neoplasia was associated with unfavourable evolution (p=.012) and heart failure with higher mortality (p=.027).

CONCLUSIONS

Outpatient antimicrobial therapy in elastomeric infusion pumps is an alternative in patients requiring prolonged intravenous treatment, and age is not a conditioning factor for inclusion in these programs. However, the presence of certain comorbidities can negatively affect the clinical course and mortality of patients.

Retrospective study of home antibiotic infusion therapy in elastomeric infusion pumps

OBJECTIVES

To describe the experience of home antibiotic infusion therapy using elastomeric infusion pumps, administered to patients admitted to the Home Hospitalization Unit of a tertiary hospital for three years and to analyse clinical evolution and mortality.

METHOD

Retrospective observational study. The medical history of the patients included in the study was reviewed. Information was obtained on personal history, antimicrobial therapy received and clinical evolution. Statistical analysis was performed using SPSS® 19 software.

RESULTS

Eighty-one patients were included, 61.7% men, with a mean age of 73.5 ± 17.5 years. The most frequent comorbidities were diabetes mellitus (30.9%) and chronic kidney disease (28.4%). Patients received a mean of 11.9 ± 8.5 days of antibiotic treatment in an elastomeric infusion pump. The main focus of infection was respiratory (27.2%), followed by bacteremia (16%) and skin and soft tissue infections (12.3%). Of the infections, 65.4% were monomicrobial, with Pseudomonas aeruginosa being the main microorganism involved (39.6%). The most commonly used antimicrobial was piperacillin/tazobactam (33.3%). The clinical course was good in 85.2% of the patients, but the mortality rate in the 30 days following the end of treatment was 24.7%. In the univariate analysis, a history of neoplasia in the last 5 years (p = 0.01) and having received fewer days of antibiotic therapy prior to the start of outpatient antimicrobial therapy in infusion pump (p = 0.04) were associated with worse clinical outcome. Age over 80 years was associated with better outcome (p = 0.03). The diagnosis of heart failure was associated with higher mortality (p = 0.026) and patients from surgical services, with lower mortality (p = 0.047). In the multivariate analysis, the presence of neoplasia was associated with unfavorable evolution (p = 0.012) and heart failure with higher mortality (p = 0.027).

CONCLUSIONS

Outpatient antimicrobial therapy in elastomeric infusion pumps is an alternative in patients requiring prolonged intravenous treatment, and age is not a conditioning factor for inclusion in these programs. However, the presence of certain comorbidities can negatively affect the clinical course and mortality of patients.

Usage of Meropenem Continuous Infusion for Treatment of Infectious Complications in Orthopedic Elderly Patients with Anemia: A Case Series

Background and Objectives: The prolonged infusion of meropenem is recommended by guidelines for the treatment of sepsis. However, studies provide controversial data on the advantages of prolonged infusions over intermittent ones. In our opinion, this can be related to age, which possibly distorts the final data, as older people have age-related characteristics. In our study, we analyzed the ventilatory status, laboratory tests and vital signs of the patient and carried out microbiological cultures. Materials and Methods: This was a prospective single-center case series investigation conducted from June 2022 to June 2023. The objective of this study was to evaluate the effectiveness of continuous infusion in elderly patients with severe infectious complications after orthopedic interventions. The primary endpoints were 28-day survival and the emergence of new multidrug-resistant strains. Secondary endpoints were long-term mortality and length of stay in the ICU. Results: Three patients (median age 65, 100% female) received a continuous infusion of meropenem. Two patients were alive at hospital discharge, and one patient died on the 105th day of hospitalization. Multi-resistant bacteria were observed in one patient. Conclusions: The use of a continuous meropenem infusion in the complex treatment of purulent-septic complications in elderly patients with periprosthetic infection and anemia probably led to clinical improvement in these case reports. However, the emergence of new pan-resistant strains and overall mortality using this infusion technique remains unclear. Further, high-quality RCTs for the elderly are needed.

Development and Validation of a Capillary Zone Electrophoresis-Tandem Mass Spectrometry Method for Simultaneous Quantification of Eight β-Lactam Antibiotics and Two β-Lactamase Inhibitors in Plasma Samples

Monitoring plasma concentrations of β-lactam antibiotics is crucial, particularly in critically ill patients, where variations in concentrations can lead to treatment failure or adverse events. Standardized antimicrobial regimens may not be effective for all patients, especially in special groups with altered physiological parameters. Pharmacokinetic/pharmacodynamic (PK/PD) studies highlight the time-dependent antibacterial activity of these antibiotics, emphasizing the need for personalized dosing. Therapeutic drug monitoring (TDM) is essential, requiring rapid and accurate analytical methods for precise determination of drugs in biological material (typically plasma or serum). This study presents a novel capillary zone electrophoresis-tandem mass spectrometry (CZE-MS/MS) method designed for the simultaneous quantification of five penicillin antibiotics, two cephalosporins, one carbapenem, and two β-lactamase inhibitors in a single run. The method involves a simple sample pretreatment-precipitation with organic solvent-and has a run time of 20 min. Optimization of CZE separation conditions revealed that 20 mM ammonium hydrogen carbonate (NH4HCO3) serves as the optimal background electrolyte (BGE). Positive electrospray ionization (ESI) mode, with isopropyl alcohol (IP)/10 mM ammonium formate water solution (50/50, v/v) as the sheath liquid, was identified as the optimal condition for MS detection. Method validation according to the Food and Drug Administration (FDA) guideline for development of bioanalytical methods demonstrated satisfactory selectivity, linearity, recovery, robustness, and stability. The method's practicality was evaluated using the Blue Applicability Grade Index (BAGI), yielding a score of 77.5. Moreover, the greenness of the proposed method was evaluated by two commonly used metric tools-Analytical GREEnness (AGREE) and Green Analytical Procedure Index (GAPI). The developed CZE-MS/MS method offers a practical and reliable approach for quantifying a broad spectrum of β-lactam antibiotics in plasma. Its ability to simultaneously quantify multiple analytes in a single run, coupled with a straightforward sample pretreatment, positions it as a valuable and prospective tool for TDM in critically ill patients.

Antimicrobial dosing recommendations during continuous renal replacement therapy: different databases, different doses

Meticulous antimicrobial management is essential among critically ill patients with acute kidney injury, particularly if renal replacement therapy is needed. Many factors affect drug removal in patients undergoing continuous renal replacement therapy CRRT. In this study, we aimed to compare current databases that are frequently used to adjust CRRT dosages of antimicrobial drugs with the gold standard. The dosage recommendations from various databases for antimicrobial drugs eliminated by CRRT were investigated. The book 'Renal Pharmacotherapy: Dosage Adjustment of Medications Eliminated by the Kidneys' was chosen as the gold standard. There were variations in the databases. Micromedex, UpToDate, and Sanford had similar rates to the gold standard of 45%, 35%, and 30%, respectively. The Micromedex database shows the most similar results to the gold standard source. In addition, a consensus was reached as a result of the expert panel meetings established to discuss the different antimicrobial dose recommendations of the databases.

Continuous infusion of beta-lactam antibiotics: narrative review of systematic reviews, and implications for outpatient parenteral antibiotic therapy

INTRODUCTION

Continuous infusion (CI) of beta-lactam antibiotics may be of benefit in some patients, particularly those with severe infections. However, most studies have been small and conflicting results have been reported. The best available evidence on clinical outcomes of beta-lactam CI comes from systematic reviews/meta-analyses that integrate the available data.

AREAS COVERED

A search of PubMed from inception to the end of February 2022 for systematic reviews of clinical outcomes with beta-lactam CI for any indication identified 12 reviews, all of which focused on hospitalized patients, most of whom were critically ill. A narrative overview of these systematic reviews/meta-analyses is provided. No systematic reviews evaluating the use of beta-lactam CI for outpatient parenteral antibiotic therapy (OPAT) were identified, as few studies have focused on this area. Relevant data are summarized, and consideration is given to issues that need to be addressed when using beta-lactam CI in the setting of OPAT.

EXPERT OPINION

Evidence from systematic reviews supports a role for beta-lactam CI in the treatment of hospitalized patients with severe/life-threatening infections. Beta-lactam CI can play a role in patients receiving OPAT for severe chronic/difficult-to-treat infections, but additional data are needed to clarify its optimal use.

"CATCH" Study: Correct Antibiotic Therapy in Continuous Hemofiltration in the Critically Ill in Continuous Renal Replacement Therapy: A Prospective Observational Study

The proper posology of antibiotics in the critically ill in CRRT is difficult to assess. We therefore performed a prospective observational cohort study to make clear hints in this topic. Our results reveal a high Sieving Coefficient for all antibiotics, equal to or higher than those described in previous papers. CVVH clearance in relation to total body clearance was significant, (i.e., >than 25% for all classes). A strong correlation between the antibiotic concentrations obtained in plasma and ultrafiltrate was found both at the peak and in the valley, with the determination of two equations that allow a new method for calculating the amount of antibiotic lost in CVVH both for trough levels and peak. Based on the results of our study and considering the limitations we believe that we can extrapolate the following final considerations: (1) it is likely to carry out a loading dose for the main antibiotics (2) subsequent administrations must take into account the daily loss identified by the linear regression equation. This angular coefficient gives the idea that the average daily loss of given antibiotic is about 25%; this implies that on the basis of the linear regression equation that correlates ultrafiltered/plasma antibiotic concentration, the dosage should be increased by 25% every day, while still ensuring a daily plasma TDM of the drug.

Antibiotic Therapy in the Critically Ill with Acute Renal Failure and Renal Replacement Therapy: A Narrative Review

The outcome for critically ill patients is burdened by a double mortality rate and a longer hospital stay in the case of sepsis or septic shock. The adequate use of antibiotics may impact on the outcome since they may affect the pharmacokinetics (Pk) and pharmacodynamics (Pd) of antibiotics in such patients. Acute renal failure (ARF) occurs in about 50% of septic patients, and the consequent need for continuous renal replacement therapy (CRRT) makes the renal elimination rate of most antibiotics highly variable. Antibiotics doses should be reduced in patients experiencing ARF, in accordance with the glomerular filtration rate (GFR), whereas posology should be increased in the case of CRRT. Since different settings of CRRT may be used, identifying a standard dosage of antibiotics is very difficult, because there is a risk of both oversimplification and failing the therapeutic efficacy. Indeed, it has been seen that, in over 25% of cases, the antibiotic therapy does not reach the necessary concentration target mainly due to lack of the proper minimal inhibitory concentration (MIC) achievement. The aim of this narrative review is to clarify whether shared algorithms exist, allowing them to inform the daily practice in the proper antibiotics posology for critically ill patients undergoing CRRT.

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.

Supramolecular Detoxification of Macromolecular Biotoxin through the Complexation by a Large-Sized Macrocycle

Biotoxins are diverse, complex, and hypertoxic, ultimately serving as grave and lasting menaces to humanity. Here, it is aimed to introduce a new detoxification methodology for macromolecular biotoxin through complexation by a very large macrocycle. A 25-mer peptide isolated from Lycosa erythrognatha spider venom (LyeTxI) is selected as the model macromolecular biotoxin. Quaterphen[4]arene, with a side length of ≈1.6 nm, has a sufficient cavity to bind LyeTxI. Hence, the water-soluble derivative of Quaterphen[4]arene (H) is designed and synthesized. H exhibits an overall host-guest complexation toward LyeTxI, resulting in a considerably high association constant of (7.01 ± 0.18) × 10⁷  m^-1 . This encapsulation of peptide is interesting as traditional macrocycles can only engulf the amino acid residues of peptides due to their limited cavity size. In vitro assay verifies that complexation by H inhibits the interactions of LyeTxI with cell membranes, thereby reducing its cytotoxicity, suppressing hemolysis, and decreasing the release of lactate dehydrogenase. Notably, the intravenous administration of H has a significant therapeutic effect on LyeTxI-poisoned mice, alleviating inflammation and tissue damage, and markedly improving the survival rate from 10% to 80%. An efficient and potentially versatile approach is provided to detoxify macromolecular biotoxins, with giant macrocycle serving as an antidote.

PK-PD Modeling and Optimal Dosing Regimen of Acetylkitasamycin against Streptococcus suis in Piglets

Streptococcus suis (S. suis) causes severe respiratory diseases in pigs and is also an important pathogen causing hidden dangers to public health and safety. Acetylkitasamycin is a new macrolide agent that has shown good activity to Gram-positive cocci such as Streptococcus. The purpose of this study was to perform pharmacokinetic–pharmacodynamic (PK-PD) modeling to formulate a dosing regimen of acetylkitasamycin for treatment of S. suis and to decrease the emergence of acetylkitasamycin-resistant S. suis. The minimal inhibitory concentration (MIC) of 110 S. suis isolates was determined by broth micro dilution method. The MIC50 of the 55 sensitive S. suis isolates was 1.21 μg/mL. The strain HB1607 with MIC close to MIC50 and high pathogenicity was used for the PK-PD experiments. The MIC and MBC of HB1607 in both MH broth and pulmonary epithelial lining fluid (PELF) was 1 and 2 μg/mL, respectively. The liquid chromatography–tandem mass spectrometry (LC-MS/MS) method was used to determine the concentration change of acetylkitasamycin in piglet plasma and PELF after intragastric administration of a single dose of 50 mg/kg b.w. acetylkitasamycin. The PK parameters were calculated by WinNolin software. The PK data showed that the maximum concentration (Cmax), peak time (Tmax), and area under the concentration–time curve (AUC) were 9.84 ± 0.39 μg/mL, 4.27 ± 0.19 h and 248.58 ± 21.17 h·μg/mL, respectively. Integration of the in vivo PK data and ex vivo PD data, an inhibition sigmoid Emax equation was established. The dosing regimen of acetylkitasamycin for the treatment S. suis infection established as 33.12 mg/kg b.w. every 12 h for 3 days. This study provided a reasonable dosing regimen for a new drug used in clinical treatment, which can effectively be used to treat S. suis infection and slow down the generation of drug resistance.

Preclinical Pharmacokinetic/Pharmacodynamic Studies and Clinical Trials in the Drug Development Process of EMA-Approved Antibacterial Agents: A Review

Development of new antibacterial agents is necessary as drug-resistant bacteria are a threat to global health. In Europe, the European Medicines Agency has been guiding this development process for more than two decades. We investigated preclinical and clinical pre-approval studies to illuminate the current authorization process with emphasis on pharmacokinetic/pharmacodynamic approaches and clinical phases. All centrally authorized systemic antibacterial and antimycobacterial drugs within the European Union were included without any time restriction. Additionally, US Food and Drug Administration-approved antibiotics of the previous 3 years, which were not yet approved by the European Medicines Agency, were included. We focused on preclinical pharmacokinetic/pharmacodynamic studies and phase II and phase III clinical trials. Furthermore, we looked at the recommended dosing regimens and approved indications. In this review, we designed tree diagrams as a new means of illustrating the development process of antibiotics to relate pharmacokinetic/pharmacodynamic phase II and III studies to approved indications. We included 23 (European Medicines Agency, 18; US Food and Drug Administration, 5) antimicrobial agents. Tetracyclines, carbapenems, and cephalosporins were the leading classes. The recommended dosing intervals were significantly shorter in time- vs exposure-dependent drugs (median 8 vs 12, p = 0.006). The majority of approved indications (i.e., acute bacterial skin and soft-tissue infection, community-acquired pneumonia, complicated intra-abdominal infection, complicated urinary tract infection, and complicated skin and soft-tissue infection) used non-inferiority trials. Phase II and III clinical trials investigating community-acquired pneumonia involved the fewest patients. Some promising drugs were marketed in recent years; the individual steps to their authorizations are illuminated. We confirmed the relevance of preclinical pharmacokinetic/pharmacodynamic studies in dosing optimization and decision making in antimicrobial drug development. Non-inferiority clinical trials predominated.

The Association Between the Frequency of Interruptions in Antibiotic Exposure and the Risk of Health Care-Associated Clostridiodes difficile Infection

Background

Although antibiotic use is an established risk factor for health care-associated Clostridiodes difficile infection, estimates of the association between infection and antibiotic use vary, depending upon how antibiotic exposure is measured.

Objectives

The purpose of this study was to explore the association between the frequency of interruptions in antibiotic exposure and the risk of health care-associated C difficile infection.

Methods

A retrospective chart review cohort study was conducted of all inpatients between 2011and 2016 from a single academic health center who received at least 1 dose of a systemic antibacterial for a cumulative duration of >3 days and ≤30 days. The measures of antibiotic exposure examined were duration—cumulative total calendar days of antibiotics therapy—and continuity—the frequency of interruptions in antibiotic exposure that was defined as the number of antibiotic treatment courses.

Results

A total of 52,445/227,967 (23%) patients received antibacterial therapy for >3 days and ≤30 days during their hospitalization. Of these, 1161 out of 52,445 (2.21%) were patients with health care-associated C difficile infection. An adjusted multivariable logistic regression analysis revealed that the risk of C difficile increased with longer cumulative days (odds ratio = 2.7; comparison of >12 days to ≤5 days) and fewer interruptions of antibiotic treatment (odds ratio = 0.78; comparison of >3 discrete antibiotic treatment courses to 1 course or continuous antibiotic treatment course; all P values < 0.05).

Conclusions

For patients who received the same number of cumulative days of therapy, the patients who had more frequently interrupted courses of antibiotic therapy were less likely to experience health care-associated C difficile infection. (Curr Ther Res Clin Exp. 2020; 81:XXX–XXX)

Antibiotics can be used to contain drug-resistant bacteria by maintaining sufficiently large sensitive populations

Standard infectious disease practice calls for aggressive drug treatment that rapidly eliminates the pathogen population before resistance can emerge. When resistance is absent, this elimination strategy can lead to complete cure. However, when resistance is already present, removing drug-sensitive cells as quickly as possible removes competitive barriers that may slow the growth of resistant cells. In contrast to the elimination strategy, a containment strategy aims to maintain the maximum tolerable number of pathogens, exploiting competitive suppression to achieve chronic control. Here, we combine in vitro experiments in computer-controlled bioreactors with mathematical modeling to investigate whether containment strategies can delay failure of antibiotic treatment regimens. To do so, we measured the "escape time" required for drug-resistant Escherichia coli populations to eclipse a threshold density maintained by adaptive antibiotic dosing. Populations containing only resistant cells rapidly escape the threshold density, but we found that matched resistant populations that also contain the maximum possible number of sensitive cells could be contained for significantly longer. The increase in escape time occurs only when the threshold density-the acceptable bacterial burden-is sufficiently high, an effect that mathematical models attribute to increased competition. The findings provide decisive experimental confirmation that maintaining the maximum number of sensitive cells can be used to contain resistance when the size of the population is sufficiently large.

Pharmacokinetics, tissue residues, and ex vivo pharmacodynamics of tylosin against Mycoplasma anatis in ducks

The pharmacokinetics of tylosin were investigated in 3 groups of ducks (n = 6). They received a single dose of tylosin (50 mg/kg) by intravenous (IV), intramuscular (IM), and oral administrations, respectively. Plasma samples were collected at various time points to 24 hr post-administration to evaluate tylosin concentration over time. Additionally, tylosin residues in tissues and its withdrawal time were assessed using 30 ducks which received tylosin orally (50 mg/kg) once daily for 5 consecutive days. After IV administration, the volume of distribution, elimination half-life, area under the plasma concentration-time curve, and the total body clearance were 7.07 ± 1.98 L/kg, 2.04 hr, 19.47 µg hr/ml, and 2.82 L hr^-1  kg^-1 , respectively. After IM and oral administrations, the maximum plasma concentrations were 3.70 and 2.75 µg/ml achieved at 1 and 2 hr, and the bioavailability was 93.95% and 75.77%, respectively. The calculated withdrawal periods of tylosin were 13, 8, and 5 days for kidney, liver, and muscle, respectively. For the pharmacodynamic profile, the minimum inhibitory concentration for tylosin against M. anatis strain 1,340 was 1 µg/ml. The calculated optimal oral dose of tylosin against M. anatis in ducks based on the ex vivo pharmacokinetic/pharmacodynamic modeling was 61 mg kg^-1  day^-1 .

Emerging frontiers in drug release control by core-shell nanofibers: a review

In recent years, core-shell (CS) nanofiber has widely been used as a carrier for controlled drug release. This outstanding attention toward CS nanofiber is mainly due to its tremendous significance in controllable drug release in specific locations. The major advantage of CS nanofibers is forming a highly porous mesh, boosting its performance for many applications, due to its large surface-to-volume ratio. This inherently high ratio has prompted electrospun fibers to be considered one of the best drug-delivery-systems available, with the capacity to enhance properties such as cell attachment, drug loading, and mass transfer. Using electrospun fibers as CS nanofibers to incorporate different cargos such as antibiotics, anticancer agents, proteins, DNA, RNA, living cells, and diverse growth factors would considerably satisfy the need for a universal carrier in the field of nanotechnology. In addition to their high surface area, other benefit included in these nanofibers is the ability to trap drugs, easily controlled morphology, and their biomimetic characteristics. In this review, by taking the best advantages of the preparation and uses of CS nanofibers, a novel work in the domain of the controlled drug delivery by nanofiber-based scaffolds is presented.

Clinical Pharmacology of Antibiotics

Antimicrobial pharmacology and its effect on prescribing is quite complex. Selecting an antibiotic that will optimally treat an infection while minimizing adverse effects and the development of resistance is only the first step, as one must also consider the patient's individual pharmacokinetic alterations and the pharmacodynamic properties of the drug when prescribing it as well. Patients with CKD may have alterations in their protein binding, volumes of distribution, kidney clearance, and nonrenal clearance that necessitates antibiotic dose adjustments to prevent the development of toxicity. Knowledge of a drug's pharmacodynamics, defined as the relationship between drug exposure and antibacterial efficacy, provides some guidance regarding the optimal way to make dose adjustments. Different pharmacodynamic goals, such as maximizing the time that free (unbound) drug concentrations spend above the minimum inhibitory concentration (MIC) for time dependent drugs (e.g., β-lactams) or maximizing the free peak-to-MIC ratio for concentration-dependent antibiotics (e.g., aminoglycosides), require different adjustment strategies; for instance, decreasing the dose while maintaining normal dosing frequency or giving normal (or even larger) doses less frequently, respectively. Patients receiving hemodialysis have other important prescribing considerations as well. The nephrologist or patient may prefer to receive antibiotics that can be administered intravenously toward the end of a dialysis session. Additionally, newer dialysis technologies and filters can increase drug removal more than originally reported. This review will discuss the place in therapy, mechanism of action, pharmacokinetic, pharmacodynamic, and other pharmacologic considerations encountered when prescribing commonly used antibiotics in patients with chronic kidney disease or ESKD.

Pharmacokinetic-pharmacodynamic modeling of tylosin against Streptococcus suis in pigs

BACKGROUND

The aim of this study was to optimize the dosage regimen of tylosin against S.suis in Pigs using pharmacokinetic-pharmacodynamic (PK-PD) modeling. The antibacterial activity of tylosin against S.suis CVCC606 was investigated in Mueller Hinton (MH) broth and serum. The objectives of this investigation were to study the PD data of tylosin against S.suis CVCC606 and the PK data of tylosin in healthy and diseased model of pigs and formulate a rational dosage regimen for the treatment of pig streptococcosis.

RESULTS

The minimum inhibitory concentrations (MIC) were 0.25 μg/mL, and the minimal bactericidal concentrations (MBC) were 1 μg/mL in MH broth and serum. The killing curve showed time-dependent activity and weak concentration-dependent antibacterial activity. A pig pneumoniae model of S. suis infection was built by inoculating subcutaneously with S. suis CVCC606. Tylosin was (10 mg/kg b.w) administered intramuscularly (IM) to the healthy and S.suis infected pigs, The pharmacokinetic properties, including area under the curve(AUC), peak concentration (C_max) and time to reach C_max (T_max), were determined in plasma using UV-HPLC method. The AUC, C_max and T_max in plasma of healthy and infected pigs were 10.80 ± 2.20 and 10.30 ± 3.46 μg.h/mL, 2.06 ± 0.43 and 2.37 ± 0.38 μg/mL, 1.95 ± 0.22 and 1.58 ± 0.49 h, respectively.

CONCLUSIONS

The in vivo PK and in vitro PD data were integrated to determine the surrogate marker of antibacterial activity, C_max/MIC, AUC/MIC and T_>MICwere 8.90, 43.21, 8.86 for healthy pigs, and 9.76, 41.18, 7.56 for infected pigs, respectively. Ex vivo AUC/MIC data were integrated with ex vivo bacterial count to calculate the values for bacteriostatic and bactericidal action, which were 10.67 h and 49.66 h for healthy pigs, 11.73 h and 43.03 h for pigs infected with S.suis. A dosage regimen of 5.32-19.50 mg/kg b.w. every 24 h should be sufficient for tylosin against S.suis.

Ceftazidime-Avibactam Population Pharmacokinetic Modeling and Pharmacodynamic Target Attainment Across Adult Indications and Patient Subgroups

Ceftazidime‐avibactam is a novel β‐lactam/β‐lactamase inhibitor combination for the treatment of serious infections caused by resistant gram‐negative pathogens. Population pharmacokinetic (PopPK) models were built to incorporate pharmacokinetic (PK) data from five phase III trials in patients with complicated intra‐abdominal infection (cIAI), complicated urinary tract infection (cUTI), or nosocomial (including ventilator‐associated) pneumonia. Ceftazidime and avibactam pharmacokinetics were well‐described by two‐compartment disposition models, with creatinine clearance (CrCL) the key covariate determining clearance variability. Steady‐state ceftazidime and avibactam exposure for most patient subgroups differed by ≤ 20% vs. healthy volunteers. Probability of PK/pharmacodynamic (PD) target attainment (free plasma ceftazidime > 8 mg/L and avibactam > 1 mg/L for ≥ 50% of dosing interval) was ≥ 94.9% in simulations for all patient subgroups, including indication and renal function categories. No exposure‐microbiological response relationship was identified because target exposures were achieved in almost all patients. These modeling results support the approved ceftazidime‐avibactam dosage regimens (2000‐500 mg every 8 hours, adjusted for CrCL ≤ 50 mL/min).

Antibiotic Stewardship: Strategies to Minimize Antibiotic Resistance While Maximizing Antibiotic Effectiveness

Empiric therapy of the septic patient in the hospital is challenging. Antibiotic stewardship is concerned with optimizing antibiotic use and minimizing resistance. Clinicians should avoid overcovering and overtreating colonizing organisms in respiratory secretions and urinary catheters. Empiric therapy should take into account the prevalence of multidrug-resistant organisms in the hospital setting. The most effective resistance prevention strategies is to preferentially select a low resistance potential antibiotic, which should be administered in the highest possible dose without toxicity for the shortest duration to eliminate the infection.

Antibiotic Dosing in Sustained Low-Efficiency Dialysis in Critically Ill Patients

Purpose of review

Sustained low-efficiency dialysis (SLED) is increasingly used as a renal replacement modality in critically ill patients with acute kidney injury (AKI) and hemodynamic instability. There is, therefore, a greater need for the understanding of the antibiotic dosage and pharmacokinetics in these patients, to provide them with optimal therapy.

Sources of information

PubMed/Medline, Embase, and Google Scholar.

Methods

PubMed/Medline, Embase, and Google Scholar databases were searched using a combination of key words: dialysis, end stage renal disease, renal failure, sustained low efficiency dialysis, extended daily dialysis, prolonged intermittent renal replacement therapy (PIRRT), and antibiotic dosing. Studies that investigated antibiotic dosing and pharmacokinetics during SLED/extended daily dialysis/PIRRT were selected for this review.

Key findings

Eleven studies met inclusion criteria and selected for data extraction. The data with regard to dialysis specifications, type of antibiotic including dosages, drug clearances, and dosage recommendations are summarized in Table 1. It is a challenge to find therapeutic doses for antibiotics during SLED therapy because, in general, only aminoglycosides and vancomycin can be assayed in clinical laboratories.

Limitations

Although current studies on antibiotic dosing in SLED are limited due to diverse and undersized patient populations, antibiotic dosage adjustments for patients receiving SLED discussed here will serve as a valuable guide. Future large-scale research should focus on establishing guidelines for antibiotic dosage in SLED.

Implications

Pharmacokinetic principles should be taken into consideration for the appropriate dosing of drugs during SLED, yet it is vital to monitor response to drug to make sure therapeutic goals are achieved. Antibiotic dosing and timing relative to the initiation of SLED may be important to maximize either the time above the minimum inhibitory concentration (MIC) (time-dependent) or the peak to MIC ratio (concentration-dependent), balancing efficacy and toxicity concerns. Critical care physicians should liaise with nephrologists to make decisions regarding appropriate antibiotic dosing in patients undergoing SLED.

Continuous and Prolonged Intravenous β-Lactam Dosing: Implications for the Clinical Laboratory

Beta-lactam antibiotics serve as a cornerstone in the management of bacterial infections because of their wide spectrum of activity and low toxicity. Since resistance rates among bacteria are continuously on the rise and the pipeline for new antibiotics does not meet this trend, an optimization of current beta-lactam treatment is needed. This review provides an overview of optimization through use of prolonged- and continuous-infusion dosing strategies compared with more traditional intermittent infusions. Included is an overview of the scientific basis for using these nontraditional prolonged- and continuous-infusion-based regimens, with a focus on major areas in which the clinical laboratory can support the clinical use of these regimens.

Strategies to enhance rational use of antibiotics in hospital: a guideline by the German Society for Infectious Diseases

Introduction

In the time of increasing resistance and paucity of new drug development there is a growing need for strategies to enhance rational use of antibiotics in German and Austrian hospitals. An evidence-based guideline on recommendations for implementation of antibiotic stewardship (ABS) programmes was developed by the German Society for Infectious Diseases in association with the following societies, associations and institutions: German Society of Hospital Pharmacists, German Society for Hygiene and Microbiology, Paul Ehrlich Society for Chemotherapy, The Austrian Association of Hospital Pharmacists, Austrian Society for Infectious Diseases and Tropical Medicine, Austrian Society for Antimicrobial Chemotherapy, Robert Koch Institute.

Materials and methods

A structured literature research was performed in the databases EMBASE, BIOSIS, MEDLINE and The Cochrane Library from January 2006 to November 2010 with an update to April 2012 (MEDLINE and The Cochrane Library). The grading of recommendations in relation to their evidence is according to the AWMF Guidance Manual and Rules for Guideline Development.

Conclusion

The guideline provides the grounds for rational use of antibiotics in hospital to counteract antimicrobial resistance and to improve the quality of care of patients with infections by maximising clinical outcomes while minimising toxicity. Requirements for a successful implementation of ABS programmes as well as core and supplemental ABS strategies are outlined. The German version of the guideline was published by the German Association of the Scientific Medical Societies (AWMF) in December 2013.

MANAGEMENT OF OSTEOMYELITIS CAUSED BY SALMONELLA ENTERICA SUBSP. HOUTENAE IN A TAYLOR'S CANTIL (AGKISTRODON BILINEATUS TAYLORI) USING AMIKACIN DELIVERED VIA OSMOTIC PUMP

An adult female Taylor's cantil (Agkistrodon bilineatus taylori) presented with marked spinal and mandibular osteomyelitis that cultured positive for Salmonella enterica subsp. houtenae, serovar IV 43:z4,z32:-. Progression of osteomyelitis was arrested by treatment using amikacin (0.026 mg/kg per hour) delivered via subcutaneous osmotic pump for 10 mo, replacing the pump every 4 wk. No adverse effects on renal function were appreciated throughout the course of therapy. Amikacin therapy was discontinued after improvement with treatment, but 5 mo later, bony lesions worsened, and an additional abscess formed at the previous pump site. The animal's condition declined and euthanasia was elected. Postmortem examination confirmed marked osteomyelitis with Salmonella infection of same serovar as the initial biopsy. This report highlights the pathogenicity of the S. enterica subsp. houtenae serovar and the ability to deliver effective amikacin dosage via osmotic pump to arrest osteomyelitis due to salmonellosis in a venomous snake.

We Give Aminoglycoside Antibiotics at the End of Hemodialysis

We often administer dialyzable medications after dialysis to ensure that adequate concentrations are maintained in the body until the next session. In the case of aminoglycosides, we may have the opportunity to dose more aggressively predialysis, and then use the clearance of the drug by dialysis to limit toxicities. Predialysis aminoglycoside dosing is intriguing, although studies evaluating the safety and efficacy of this approach are necessary before it can be used routinely.

An audit and feedback intervention study increased adherence to antibiotic prescribing guidelines at a Norwegian hospital

Background

Appropriate antibiotic prescribing is associated with favourable levels of antimicrobial resistance (AMR) and clinical outcomes. Most intervention studies on antibiotic prescribing originate from settings with high level of AMR. In a Norwegian hospital setting with low level of AMR, the literature on interventions for promoting guideline-recommended antibiotic prescribing in hospital is scarce and requested. Preliminary studies have shown improvement potentials regarding antibiotic prescribing according to guidelines. We aimed to promote appropriate antibiotic prescribing in patients with community-acquired pneumonia (CAP) and acute exacerbations of chronic obstructive pulmonary disease (AECOPD) at a respiratory medicine department in a Norwegian University hospital. Our specific objectives were to increase prescribing of appropriate empirical antibiotics, reduce high-dose benzylpenicillin and reduce total treatment duration.

Methods

We performed an audit and feedback intervention study, combined with distribution of a recently published pocket version of the national clinical practice guideline. We included patients discharged with CAP or AECOPD and prescribed antibiotics during hospital stay, and excluded those presenting with aspiration, nosocomial infection and co-infections. The pre- and post-intervention period was 9 and 6 months, respectively. Feedback was provided orally to the department physicians at an internal-educational meeting. To explore the effect of the intervention on appropriate empirical antibiotics and mean total treatment duration we applied before-after analysis (Student’s t-test) and interrupted time series (ITS). We used Pearson’s χ2 to compare dose changes.

Results

In the pre-and post-intervention period we included 253 and 155 patients, respectively. Following the intervention, overall mean prescribing of appropriate empirical antibiotics increased from 61.7 to 83.8 % (P < 0.001), overall mean total treatment duration decreased from 11.2 to 10.4 days (P = 0.015), and prescribing of high-dose benzylpenicillin decreased from 48.8 to 38.6 % (P = 0.125). With ITS we found that six months post-intervention, the effect on appropriate empirical antibiotic prescribing had increased and sustained, while the effect on treatment duration was at pre-intervention level.

Conclusion

The combination of audit and feedback plus distribution of a pocket version of guideline recommendations led to a substantial increase in prescribing of appropriate empirical antibiotics, which is important due to favourable effect on AMR and clinical outcomes.

Electronic supplementary material

The online version of this article (doi:10.1186/s12879-016-1426-1) contains supplementary material, which is available to authorized users.

Application of PK/PD Modeling in Veterinary Field: Dose Optimization and Drug Resistance Prediction

Among veterinary drugs, antibiotics are frequently used. The true mean of antibiotic treatment is to administer dose of drug that will have enough high possibility of attaining the preferred curative effect, with adequately low chance of concentration associated toxicity. Rising of antibacterial resistance and lack of novel antibiotic is a global crisis; therefore there is an urgent need to overcome this problem. Inappropriate antibiotic selection, group treatment, and suboptimal dosing are mostly responsible for the mentioned problem. One approach to minimizing the antibacterial resistance is to optimize the dosage regimen. PK/PD model is important realm to be used for that purpose from several years. PK/PD model describes the relationship between drug potency, microorganism exposed to drug, and the effect observed. Proper use of the most modern PK/PD modeling approaches in veterinary medicine can optimize the dosage for patient, which in turn reduce toxicity and reduce the emergence of resistance. The aim of this review is to look at the existing state and application of PK/PD in veterinary medicine based on in vitro, in vivo, healthy, and disease model.

Current strategies for sustaining drug release from electrospun nanofibers

Electrospun drug-eluting fibers are emerging as a novel dosage form for multipurpose prevention against sexually transmitted infections, including HIV, and unintended pregnancy. Previous work from our lab and others show the versatility of this platform to deliver large doses of physico-chemically diverse agents. However, there is still an unmet need to develop practical fiber formulations for water-soluble small molecule drugs needed at high dosing due to intrinsic low potency or desire for sustained prevention. To date, most sustained release fibers have been restricted to the delivery of biologics or hydrophobic small molecules at low drug loading of typically <1 wt.%, which is often impractical for most clinical applications. For hydrophilic small molecule drugs, their high aqueous solubility and poor partitioning and incompatibility with insoluble polymers make long-term release even more challenging. Here we investigate several existing strategies to sustain release of hydrophilic small molecule drugs that are highly-loaded in electrospun fibers. In particular, we investigate what is known about the design constraints required to realize multi-day release from fibers fabricated from uniaxial and coaxial electrospinning.

Antibiotic Dosing in Patients With Acute Kidney Injury: "Enough But Not Too Much"

Increasing evidence suggests that antibiotic dosing in critically ill patients with acute kidney injury (AKI) often does not achieve pharmacodynamic goals, and the continued high mortality rate due to infectious causes appears to confirm these findings. Although there are compelling reasons why clinicians should use more aggressive antibiotic dosing, particularly in patients receiving aggressive renal replacement therapies, concerns for toxicity associated with higher doses are real. The presence of multisystem organ failure and polypharmacy predispose these patients to drug toxicity. This article examines the pharmacokinetic and pharmacodynamic consequences of critical illness, AKI, and renal replacement therapy and describes potential solutions to help clinicians give "enough but not too much" in these very complicated patients.

In vitro effects of sulbactam combinations with different antibiotic groups against clinical Acinetobacter baumannii isolates

Treatment of multidrug resistant (MDR) Acinetobacter baumannii infections causes some problems as a result of possessing various antibacterial resistance mechanisms against available antibiotics. Combination of antibiotics, acting by different mechanisms, is used for the treatment of MDR bacterial infections. It is an important factor to determine synergy or antagonism between agents in the combination for the constitution of effective therapy. The study aimed to determine In vitro interactions interpreted according to calculated fractional inhibitory concentration (FIC) index between sulbactam and ceftazidime, ceftriaxone, cefepime, ciprofloxacin, gentamicin, meropenem, tigecycline, and colistin. Ten clinical isolates of A. baumannii were tested for determination of synergistic effects of sulbactam with different antimicrobial combinations. Minimal inhibitory concentration (MIC) values of both sulbactam and combined antibiotics decreased 2- to 128-fold. Synergy and partial synergy were determined in combination of sulbactam with ceftazidime and gentamicin (FIC index: ≤ 0.5 or >0.5 to <1) and MIC values of both ceftazidime and gentamicin for five isolates fell down below the susceptibility break point. Similarly, MIC value of ciprofloxacin for six ciprofloxacin resistant isolates was determined as below the susceptibility break point in combination. However, all isolates were susceptible to colistin and tigecycline, MIC values of both were decreased in combination with sulbactam. Although synergistic and partial synergistic effects were observed in the combination of sulbactam and ceftriaxone, all isolates remained resistant to ceftriaxone. The effect of cefepime-sulbactam combination was synergy in five, partial synergy in one and indifferent in four isolates. Meropenem and sulbactam showed a partial synergistic effect (FIC index: >0.5 to <1) in three, an additive effect (FIC index: 1) in one and an indifferent effect (FIC index: >1-2) in six isolates. Antagonism was not determined in any combination for clinical A. baumannii isolates in the study. In conclusion, sulbactam is a good candidate for combination treatment regimes for MDR A. baumannii infections.

Guidelines for aminoglycoside use and applicability to geriatric patients

OBJECTIVES

The authors had for objective to evaluate the applicability of AFSSAPS guidelines for aminoglycoside use to geriatric patients.

METHODS

Theoretical doses and dosing regimens allowing reaching target concentrations in this population were calculated by applying a pharmacokinetic model to 30 geriatric patients treated by amikacin.

RESULTS

The dose allowing reaching a maximum concentration of 60 mg/L was 1.217 mg on average. The time required to reach a blood concentration lower than or equal to 2.5mg/L was 62.5±70.4 hours. Forty-six percent of patients had a trough concentration greater than 2.5 mg/L, 48 hours after administration. For these patients, the time between critical minimum inhibitory concentration (MIC) and toxicity threshold concentration was 21.9±14.9 hours.

CONCLUSION

Reaching a target concentration can be problematic in geriatric patients. It is frequently necessary to use dosing intervals greater than 48 hours. The effectiveness and safety of these regimens remain uncertain.

A clinical pathway for community-acquired pneumonia: an observational cohort study

BACKGROUND

Six hospitals instituted a voluntary, system-wide, pathway for community acquired pneumonia (CAP). We proposed this study to determine the impact of pathway antibiotics on patient survival, hospital length of stay (LOS), and total hospital cost.

METHODS

Data were collected for adults from six U.S. hospitals with a principal CAP discharge diagnosis code, a chest infiltrate, and medical notes indicative of CAP from 2005-2007. Pathway and non-pathway cohorts were assigned according to antibiotics received within 48 hours of admission. Pathway antibiotics included levofloxacin 750 mg monotherapy or ceftriaxone 1000 mg plus azithromycin 500 mg daily. Multivariable regression models assessed 90-day mortality, hospital LOS, total hospital cost, and total pharmacy cost.

RESULTS

Overall, 792 patients met study criteria. Of these, 505 (64%) received pathway antibiotics and 287 (36%) received non-pathway antibiotics. Adjusted means and p-values were derived from Least Squares regression models that included Pneumonia Severity Index risk class, patient age, heart failure, chronic obstructive pulmonary disease, and admitting hospital as covariates. After adjustment, patients who received pathway antibiotics experienced lower adjusted 90-day mortality (p = 0.02), shorter mean hospital LOS (3.9 vs. 5.0 days, p < 0.01), lower mean hospital costs ($2,485 vs. $3,281, p = 0.02), and similar mean pharmacy costs ($356 vs. $442, p = 0.11).

CONCLUSIONS

Pathway antibiotics were associated with improved patient survival, hospital LOS, and total hospital cost for patients admitted to the hospital with CAP.

Antibiotic dosing in critically ill patients with acute kidney injury

A common cause of acute kidney injury (AKI) is sepsis, which makes appropriate dosing of antibiotics in these patients essential. Drug dosing in critically ill patients with AKI, however, can be complicated. Critical illness and AKI can both substantially alter pharmacokinetic parameters as compared with healthy individuals or patients with end-stage renal disease. Furthermore, drug pharmacokinetic parameters are highly variable within the critically ill population. The volume of distribution of hydrophilic agents can increase as a result of fluid overload and decreased binding of the drug to serum proteins, and antibiotic loading doses must be adjusted upwards to account for these changes. Although renal elimination of drugs is decreased in patients with AKI, residual renal function in conjunction with renal replacement therapies (RRTs) result in enhanced drug clearance, and maintenance doses must reflect this situation. Antibiotic dosing decisions should be individualized to take into account patient-related, RRT-related, and drug-related factors. Efforts must also be made to optimize the attainment of antibiotic pharmacodynamic goals in this population.

Antibiotic pharmacokinetic and pharmacodynamic considerations in patients with kidney disease

Although pharmacokinetic changes occurring in kidney disease are well described, pharmacodynamics in kidney disease is rarely considered. Knowledge of pharmacodynamic principles can allow a clinician to maximize an antibiotic's effectiveness while minimizing adverse effects and antibacterial resistance. An antibiotic's pharmacokinetic and pharmacodynamic profiles should drive dose adjustment decisions in patients with kidney disease. For example, although the half-lives of beta-lactams and aminoglycosides are both prolonged in these patients, beta-lactams exhibit time-dependent antibacterial activity; consequently, maintenance doses should be smaller but given at the same interval. In contrast, aminoglycosides are concentration-dependent antibiotics; hence prolongation of the dosing interval while using larger doses may be advantageous. The timing of drug administration in relation to hemodialysis may be used to achieve specific pharmacodynamic goals. Aminoglycosides given before hemodialysis generate high peaks, whereas subsequent dialytic drug removal minimizes the area under the serum concentration-time curve, potentially decreasing the risk of developing toxicity. Furthermore, new dialysis prescribing patterns (eg, automated peritoneal dialysis, nocturnal dialysis) affect pharmacokinetic and pharmacodynamic parameters in ways not appreciated by clinicians. Studies quantifying the often considerable drug removal with these therapies, as well as efforts to identify pharmacodynamic targets in patients with kidney disease are essential. This paper reviews pharmacodynamic as well as pharmacokinetic issues that should be considered when prescribing antibiotics to treat infections in this population.

Recent Publications on Medications and Pharmacy

Hospital Pharmacy presents this feature to keep pharmacists abreast of new publications in the medical/pharmacy literature. Articles of interest regarding a broad scope of topics are abstracted monthly.