Tissue Penetration of Antimicrobials in Intensive Care Unit Patients: A Systematic Review—Part I

Infectious complications after traumatic spine injury requiring surgery in a French level-1 trauma center: An observational study

BACKGROUND

Traumatic spine injury (TSI) is a prevalent condition that often requires surgical intervention. Two serious infectious complications after surgery are surgical site infections (SSI) and lower respiratory tract infections (LRTI). Yet, studies on SSI and LRTI on trauma patients, particularly with a specific focus on microbiology are lacking. The primary aim of this study is to investigate the prevalence rate of early SSI, occurring within one month of surgery or three months when instrumented, and LRTI in level-1 trauma center patients requiring surgery after TSI.

METHODS

This monocenter retrospective observational study was conducted at an academic level-1 trauma center, including patients with TSI requiring surgery. Data on patients' baseline characteristics, trauma related information, initial and intra-operative management, infectious complications data and hospitalization outcomes were collected. The two primary outcomes were the prevalence of early SSI and LRTI. Secondary outcomes included the identification of factors associated with developing these infections, analysis of identified organisms, and assessment of clinical outcomes.

RESULTS

A total of 2606 patients were screened between May 2018 and October 2022, 194 were included. Most of them were polytrauma patients defined by Injury Severity Score ≥ 16 (71 %). Early SSI occurred in 20 patients (10 %) and LRTI occurred in 58 patients (30 %). The number of vertebral levels instrumented (odds ratio [OR] 1.24, 95 % confidence interval [95 % CI] 1.01-1.52) was associated with SSI. The causative organisms were predominantly Gram-positive cocci (19/36 identified organisms). Factors associated with LRTI were an injury severity score ≥ 25 (OR 7.41; 95 % CI, 3.28-17.99), spinal injury at levels C3-C7 (OR 2.24; 95 % CI 1.01-5.14) and antibiotics during initial management (OR 7.09; 95 % CI, 2.71-20.49). The causative organisms were predominantly Gram-negative bacilli (58/80 identified organisms). Patients with LRTI experienced longer hospital stays, extended durations of mechanical ventilation, and higher mortality rates at 30 days and one year than those without.

CONCLUSION

Early SSI and LRTI are underestimated complications in severe trauma patients with TSI requiring surgery. Identifying risk factors and causative organisms is an important step for advancing research on targeted prevention and treatment of SSI and LRTI after trauma.

Effective Management of a Skin and Soft Tissue Infection Caused by Community-Acquired MRSA Through Triple-Targeted Therapy Along with Aggressive Source Control: A Case Report

Background: Methicillin-resistant Staphylococcus aureus (MRSA) is a significant cause of healthcare-associated infections in Europe. It has become increasingly prevalent in community settings, causing skin and soft tissue infections (SSTIs). Managing community-acquired (CA) MRSA infections is challenging due to its high virulence and resistance to common antibiotics, and prevention outside the hospital setting is complex. Combination therapy has demonstrated efficacy in the treatment of severe MRSA infections. Furthermore, surgical source control is critical in treating CA-MRSA infections, involving removing the primary infection site to interrupt bacterial replication. Timeliness and a correct surgical approach are essential for successful treatment outcomes and improved quality of life. Methods: This report details the case of a 15-year-old athlete who was admitted to the intensive care unit with septic shock caused by CA-MRSA. Results: Despite initial treatment, his condition rapidly worsened. A computed tomography (CT) scan identified multiple abscesses (in the lungs, limbs, thyroid, and subscapular region) along with other complications. To achieve adequate tissue concentrations at all affected sites, a triple-targeted antimicrobial therapy was initiated and adjusted based on therapeutic drug monitoring (TDM). At the same time, daily surgical debridement was performed. The patient responded significantly to this treatment, and blood cultures eventually returned negative. Conclusions: A multidisciplinary approach involving early source control, tailored antimicrobial therapy, and, if monotherapy fails to control infection, combination therapy is advisable to treat life-threatening CA-MRSA infections.

Translating PK-PD principles into improved methodology for clinical trials which compare intermittent with prolonged infusion of beta-lactam antibiotics

Based on the fact that beta-lactam antibiotics demonstrate time-dependent killing, different dosing strategies have been implemented to increase the time that free (f) (unbound) antibiotic concentrations remain above the Minimal Inhibitory Concentration (MIC), including prolonged and continuous infusion. Multiple studies have been performed that compared continuous with traditional intermittent infusion to improve outcomes in patients with severe sepsis and/or septic shock. These studies have yielded inconsistent results for patients as measured by clinical response to treatment and mortality due to heterogeneity of included patients, pathogens, dosing strategies and the absence of Therapeutic Drug Monitoring (TDM). The MERCY and BLING III studies failed to show a difference in mortality between patients randomized to receive continuous and intermittent infusion of beta-lactam antibiotics.
 A deeper understanding of pharmacokinetic (PK) and pharmacodynamic (PD) mechanisms that occur in critically ill patients should guide us in dose optimization and improvement in methodology for future clinical trials.

A phase 2 randomized, placebo-controlled trial of inulin for the prevention of gut pathogen colonization and infection among patients admitted to the intensive care unit for sepsis

BACKGROUND

Patients admitted to the intensive care unit (ICU) often have gut colonization with pathogenic bacteria and such colonization is associated with increased risk for death and infection. We conducted a trial to determine whether a prebiotic would improve the gut microbiome to decrease gut pathogen colonization and decrease downstream risk for infection among newly admitted medical ICU patients with sepsis.

METHODS

This was a randomized, double-blind, placebo-controlled trial of adults who were admitted to the medical ICU for sepsis and were receiving broad-spectrum antibiotics. Participants were randomized 1:1:1 to placebo, inulin 16 g/day, or inulin 32 g/day which were given for seven days. The trial primary outcome was a surrogate measure for gut colonization resistance, namely the within-individual change from ICU admission to Day 3 in the relative abundance of short chain fatty acid (SCFA)-producing bacteria based on rectal swabs. Additional outcomes sought to evaluate the impact of inulin on the gut microbiome and downstream clinical effects.

RESULTS

Ninety participants were analyzed including 30 in each study group. There was no difference between study groups in the within-individual change in the relative abundance of SCFA-producing bacteria from ICU admission to ICU Day 3 (placebo: 0.0% change, IQR - 8·0% to + 7·4% vs. combined inulin: 0·0% change, IQR - 10·1% to + 4·8%; p = 0·91). At end-of-treatment on ICU Day 7, inulin did not affect SCFA-producer levels, microbiome diversity, or rates of gut colonization with pathogenic bacteria. After 30 days of clinical follow-up, inulin did not affect rates of death or clinical, culture-proven infection. Patients who died or developed culture-proven infections had lower relative abundance of SCFA-producing bacteria at ICU admission compared to those who did not (p = 0·03).

CONCLUSIONS

Prebiotic fiber had minimal impact on the gut microbiome in the ICU and did not improve clinical outcomes.

TRIAL REGISTRATION

Clinicaltrials.gov: NCT03865706.

Improving pharmacokinetic/pharmacodynamic outcomes of antimicrobial therapy for pneumonia in the ICU

INTRODUCTION

Pneumonia remains a significant global health challenge due to its high prevalence and mortality rate, and challenging treatment. This review explores the best strategies to optimize the antibiotic therapy for pneumonia in critically ill patients, focusing on pharmacokinetics, pharmacodynamics, and therapeutic data.

AREAS COVERED

A review of scientific publications on severe pneumonia highlights the challenges of optimizing antibiotic use to improve lung diffusion, bacterial killing, and achieving PK/PD targets, emphasizing the need to understand microbiological epidemiology and MIC breakpoints. Key strategies like nebulization, therapeutic drug monitoring, and emerging technologies such as ELF TDM and nanomaterial-based drug delivery systems are essential for optimizing PK/PD outcomes and addressing antimicrobial resistance.

EXPERT OPINION

Improving our understanding of pulmonary pharmacokinetics and optimizing their tissue diffusion are instrumental for achieving precision antibiotic therapy for severe pneumonia. By addressing current limitations and embracing interdisciplinary collaboration, we can pave the way for more efficient personalized approaches in infectious disease management.

The relation between inflammatory biomarkers and drug pharmacokinetics in the critically ill patients: a scoping review

BACKGROUND

The level of inflammation alters drug pharmacokinetics (PK) in critically ill patients. This might compromise treatment efficacy. Understanding the specific effects of inflammation, measured by biomarkers, on drug absorption, distribution, metabolism, and excretion is might help in optimizing dosing strategies.

OBJECTIVES

This review investigates the relationship between inflammatory biomarkers and PK parameters absorption, distribution, metabolism and excretion (ADME) in critically ill patients, providing insight in the complexity of dosing drugs in critically ill patients.

METHOD

Following PRISMA guidelines, we conducted a comprehensive search of Medline, Embase, Web of Science, and Cochrane databases (January 1946-November 2023). Studies examining inflammatory biomarkers, PK parameters, or drug exposure in critically ill patients were included. Records were screened by title, abstract, and full text, with any discrepancies resolved through discussion or consultation with a third reviewer.

RESULTS

Of the 4479 records screened, 31 met our inclusion criteria: 2 on absorption, 7 on distribution, 17 on metabolism, and 6 on excretion. In general, results are only available for a limited number of drugs, and most studies are done only looking at one of the components of ADME. Higher levels of inflammatory biomarkers may increase or decrease drug absorption depending on whether the drug undergoes hepatic first-pass elimination. For drug distribution, inflammation is negatively correlated with drug protein binding capacity, positively correlated with cerebrospinal fluid penetration, and negatively correlated with peritoneal penetration. Metabolizing capacity of most drugs was inversely correlated with inflammatory biomarkers. Regarding excretion, inflammation can lead to reduced drug clearance, except in the neonatal population.

CONCLUSION

Inflammatory biomarkers can offer valuable information regarding altered PK in critically ill patients. Our findings emphasize the need to consider inflammation-driven PK variability when individualizing drug therapy in this setting, at the same time research is limited to certain drugs and needs further research, also including pharmacodynamics.

Pharmacokinetics of Piperacillin-Tazobactam in Critically Ill Patients with Open Abdomen and Vacuum-Assisted Wound Closure: Dosing Considerations Using Monte Carlo Simulation

BACKGROUND

Open abdomen with vacuum-assisted wound closure therapy (OA/VAC) is frequently used in critically ill patients although the impact of OA/VAC on antibiotics pharmacokinetics (PK) remains unknown. We thus aimed to characterize the PK of piperacillin-tazobactam (PTZ) in critically ill patients with OA/VAC and assess the optimal dosing regimens based on pharmacodynamics (PD) target attainment.

METHODS

Over a 15-month study period, 45 patients with OA/VAC treated with PTZ administered continuously and adapted to 24 h creatinine clearance (CLCR) underwent measurements of free concentrations in their plasma, urine, VAC exudate, and peritoneal fluid. Population PK modeling was performed considering the effect of covariates, and Monte Carlo simulations were employed to determine the probability of target attainment (PTA) for the PK/PD targets (100% fT > 16 mg/L) in the plasma and at the peritoneal site at steady state.

RESULTS

Piperacillin concentrations were described using a two-compartment model, with age and total body weight as significant covariates for central volume of distribution (V1) and estimated renal function for clearance (CL). Tazobactam concentrations were described using a two-compartment model with estimated renal function as a significant covariate. The central volume of distributions V1 of piperacillin and tazobactam were 21.2 and 23.2 L, respectively. The VAC-induced peritoneal clearance was negligible compared to renal clearance. Most patients achieved the desirable PK/PD target when using a CLCR-pondered PTZ dosing regimen from 12 g/1.5 g/day to 20 g/2.5 g/day.

CONCLUSIONS

Despite a wide inter-individual variability, the influence of OA/VAC on piperacillin and tazobactam PK parameters is not straightforward. The use of a CLCR-pondered PTZ dosing regimen from 12 g/1.5 g/day to 20 g/2.5 g/day is needed to reach a PTA > 85%.

Artificial Intelligence to Close the Gap between Pharmacokinetic/Pharmacodynamic Targets and Clinical Outcomes in Critically Ill Patients: A Narrative Review on Beta Lactams

Antimicrobial dosing can be a complex challenge. Although a solid rationale exists for a link between antibiotic exposure and outcome, conflicting data suggest a poor correlation between pharmacokinetic/pharmacodynamic targets and infection control. Different reasons may lead to this discrepancy: poor tissue penetration by β-lactams due to inflammation and inadequate tissue perfusion; different bacterial response to antibiotics and biofilms; heterogeneity of the host's immune response and drug metabolism; bacterial tolerance and acquisition of resistance during therapy. Consequently, either a fixed dose of antibiotics or a fixed target concentration may be doomed to fail. The role of biomarkers in understanding and monitoring host response to infection is also incompletely defined. Nowadays, with the ever-growing stream of data collected in hospitals, utilizing the most efficient analytical tools may lead to better personalization of therapy. The rise of artificial intelligence and machine learning has allowed large amounts of data to be rapidly accessed and analyzed. These unsupervised learning models can apprehend the data structure and identify homogeneous subgroups, facilitating the individualization of medical interventions. This review aims to discuss the challenges of β-lactam dosing, focusing on its pharmacodynamics and the new challenges and opportunities arising from integrating machine learning algorithms to personalize patient treatment.

Molecular epidemiology and clinical significance of carbapenemase genes in carbapenem-resistant Acinetobacter baumannii isolates in southern Poland

INTRODUCTION

A complex interplay between Acinetobacter spp., patients, and the environment has made it increasingly difficult to optimally treat patients infected with Acinetobacter spp., mainly due to rising antimicrobial resistance and challenges with surveillance.

OBJECTIVES

This study evaluated carbapenem‑resistant A. baumannii (CRAB) isolates to determine their resistance profiles and the presence of specific β‑lactamases to inform CRAB surveillance upon hospital admission and regional empiric antibiotic therapies.

PATIENTS AND METHODS

The study was conducted at 4 hospitals in southern Poland between June and December 2022. Only health care-associated infections caused by A. baumannii were considered. A total of 82 CRAB isolates were included in the analysis. Species identification was performed by matrix‑assisted laser desorption / ionization time‑of‑flight mass spectrometry, antimicrobial susceptibility was determined phenotypically, and polymerase chain reactions were carried out to identify the resistance genes.

RESULTS

Depending on the hospital, the incidence of CRAB infections varied from 428.6 to 759.5 per 10 000 admissions in intensive care units (ICUs), and from 0.3 to 21 per 10 000 admissions in non‑ICUs. CRAB antibiotic susceptibility was the highest for cefiderocol (100%), colistin (96%), tigecycline (77%), gentamicin (51%), and ampicillin / sulbactam (36%). The most prevalent blaOXA genes were blaOXA‑66‑1 (95%) and blaOXA‑40 (71%), and additionally the extended‑spectrum β‑lactamase gene blaTEM‑1 (41%).

CONCLUSION

An unexpectedly high incidence of CRAB infections occurred in Polish hospitals. There is a need for effective CRAB prevention and control that includes effective hospital screening, national surveillance, and improved treatment options.

Cefepime distribution by microdialysis in peritoneal fluid of rats with or without experimental peritonitis

The aim of this study was to investigate the penetration of cefepime into rat peritoneal fluid by microdialysis and to determine the relationship between unbound drug plasma and tissue concentration in healthy animals and in a sepsis model established through cecal ligation and puncture-induced peritonitis. Probe recovery was performed by dialysis and retrodialysis. Cefepime was administered at a dose of 110 mg/kg intravenously. Samples were collected for about 4 h, and concentrations were determined by liquid chromatography-electrospray ionization-QTOF MS. Tissue penetration was also determined. Probe recovery in vivo was 38.78% ± 3.31% and 38.83% ± 2.74% in the control and peritonitis groups, respectively. Cefepime was rapidly distributed in the peritoneal fluid in both groups. The peritoneal fluid/plasma cefepime ratio was 0.38 and 0.32 for the control and peritonitis groups, respectively. Cefepime concentrations were above the MIC of 4 mg/L for the main enterobacteria. The infection model that was used had no apparent effect on the pharmacokinetics of cefepime in rats. This was the first study to determine free cefepime concentrations in the peritoneal fluid of healthy rats and rats with experimental peritonitis.

Meropenem-Vaborbactam for the Treatment of Post-Neurosurgical Meningitis Caused by KPC Producer Klebsiella Pneumoniae: A Case Report and Review of the Literature

Meningitis and ventriculitis, due to carbapenem-resistant Enterobacterales, are frequently associated with significant morbidity and mortality. In the case of multi-drug-resistant pathogens, it is necessary to consider the limited susceptibility profile as well as the penetration of the antimicrobials into the brain. Limited data are available regarding the treatment of central nervous system infections caused by carbapenem-resistant Enterobacterales. We report a study of a patient treated with meropenem-vaborbactam in the case of post-neurosurgical meningitis due to carbapenemase-producing Klebsiella pneumoniae (CPKP).

Have We Neglected to Study Target-Site Drug Exposure in Children? A Systematic Review of the Literature

BACKGROUND AND OBJECTIVE

Drug dosing should ideally be based on the drug concentrations at the target site, which, for most drugs, corresponds to the tissue. The exact influence of growth and development on drug tissue distribution is unclear. This systematic review compiles the current knowledge on the tissue distribution of systemically applied drugs in children, with the aim to identify priorities in tissue pharmacokinetic (PK) research in this population.

METHODS

A systematic literature search was performed in the MEDLINE and Embase databases.

RESULTS

Forty-two relevant articles were identified, of which 71% investigated antibiotics, while drug classes from the other studies were anticancer drugs, antifungals, anthelmintics, sedatives, thyreostatics, immunomodulators, antiarrhythmics, and exon skipping therapy. The majority of studies (83%) applied tissue biopsy as the sampling technique. Tonsil and/or adenoid tissue was most frequently examined (70% of all included patients). The majority of studies had a small sample size (median 9, range 1-93), did not include the youngest age categories (neonates and infants), and were of low reporting quality. Due to the heterogeneous data from different study compounds, dosing schedules, populations, and target tissues, the possibility for comparison of PK data between studies was limited.

CONCLUSION

The influence of growth and development on drug tissue distribution continues to be a knowledge gap, due to the paucity of tissue PK data in children, especially in the younger age categories. Future research in this field should be encouraged as techniques to safely investigate drug tissue disposition in children are available.

Co-Administration of High-Dose Nebulized Colistin for Acinetobacter baumannii Bacteremic Ventilator-Associated Pneumonia: Impact on Outcomes

Acinetobacter baumannii (A. baumannii) is a difficult-to-treat (DTR) pathogen that causes ventilator-associated pneumonia (VAP) associated with high mortality. To improve the outcome of DTR A. Baumannii VAP, nebulized colistin (NC) was introduced with promising but conflicting results on mortality in earlier studies. Currently, NC is used at a much higher daily dose compared to the past. Nevertheless, there is little evidence on the effect of high-dose NC on the outcomes of A. baumannii VAPs, especially in the current era where the percentage of colistin-resistant A. baumannii strains is rising. We conducted a retrospective study comparing bacteremic A. baumannii VAP patients who were treated with and without NC co-administration and were admitted in the Intensive Care Unit of University Hospital of Ioannina from March 2020 to August 2023. Overall, 59 patients (21 and 38 with and without NC coadministration, respectively) were included. Both 28-day and 7-day mortalities were significantly lower in the patient group treated with NC (52.4% vs. 78.9%, p 0.034 and 9.5% vs. 47.4%, p 0.003, respectively). Patients treated with NC had a higher percentage of sepsis resolution by day 7 (38.1% vs. 13.5%, p 0.023) and were more likely to be off vasopressors by day 7 (28.6% vs. 8.1%, p 0.039). The addition of NC in the treatment regime of A. baumannii VAP decreased mortality.

Higher Brain Uptake of Gentamicin and Ceftazidime under Isoflurane Anesthesia Compared to Ketamine/Xylazine

We have recently shown that the volatile anesthetics isoflurane and sevoflurane acutely enhance the brain uptake of the hydrophilic markers sucrose and mannitol about two-fold from an awake condition, while the combined injection of the anesthetic agents ketamine and xylazine has no effect. The present study investigated two small-molecule hydrophilic drugs with potential neurotoxicity, the antibiotic agents ceftazidime and gentamicin. Transport studies using an in vitro blood-brain barrier (BBB) model, a monolayer of induced pluripotent stem cell-derived human brain microvascular endothelial cells seeded on Transwells, and LC-MS/MS analysis demonstrated the low permeability of both drugs in the range of sucrose, with permeability coefficients of 6.62 × 10-7 ± 2.34 × 10-7 cm/s for ceftazidime and 7.38 × 10-7 ± 2.29 × 10-7 cm/s for gentamicin. In vivo brain uptake studies of ceftazidime or gentamicin after IV doses of 25 mg/kg were performed in groups of 5-6 mice anesthetized at typical doses for surgical procedures with either isoflurane (1.5-2% v/v) or ketamine/xylazine (100:10 mg/kg I.P.). The brain uptake clearance, Kin, for ceftazidime increased from 0.033 ± 0.003 μL min-1 g-1 in the ketamine/xylazine group to 0.057 ± 0.006 μL min-1 g-1 in the isoflurane group (p = 0.0001), and from 0.052 ± 0.016 μL min-1 g-1 to 0.101 ± 0.034 μL min-1 g-1 (p = 0.0005) for gentamicin. We did not test the dose dependency of the uptake, because neither ceftazidime nor gentamicin are known substrates of any active uptake or efflux transporters at the BBB. In conclusion, the present study extends our previous findings with permeability markers and suggests that inhalational anesthetic isoflurane increases the BBB permeability of hydrophilic small-molecule endobiotics or xenobiotics when compared to the injection of ketamine/xylazine. This may be of clinical relevance in the case of potential neurotoxic substances.

Safety and effectiveness of fifth generation cephalosporins for the treatment of methicillin-resistant staphylococcus aureus bloodstream infections: a narrative review exploring past, present, and future

INTRODUCTION

Methicillin-resistant Staphylococcus aureus (MRSA) bloodstream infection (BSI) is a major issue in healthcare, since it is often associated with endocarditis or deep site foci. Relevant morbidity and mortality associated with MRSA-BSIs forced the development of new antibiotic strategies; in particular, this review will focus the attention on fifth-generation cephalosporins (ceftaroline/ceftobiprole), that are the only ß-lactams active against MRSA.

AREAS COVERED

The review discusses the available randomized controlled trials and real-world observational studies conducted on safety and effectiveness of ceftaroline/ceftobiprole for the treatment of MRSA-BSIs. Finally, a proposal of MRSA-BSI treatment flowchart, based on fifth-generation cephalosporins, is described.

EXPERT OPINION

The use of anti-MRSA cephalosporins is an acceptable choice either in monotherapy or combination therapy for the treatment of MRSA-BSIs due to their relevant effectiveness and safety. Particularly, their use may be advisable in combination therapy in case of severe infections (including endocarditis or persistent bacteriemia) or in monotherapy in subjects at higher risk of drugs-induced toxicity with older regimens. On the contrary, caution should be taken in case of suspected/ascertained central nervous system infections due to inconsistent data regarding penetration of these drugs in cerebrospinal fluid and brain tissues.

Ceftazidime/Avibactam and Meropenem/Vaborbactam for the Management of Enterobacterales Infections: A Narrative Review, Clinical Considerations, and Expert Opinion

This comprehensive review examines the unique attributes, distinctions, and clinical implications of ceftazidime-avibactam (CAZ-AVI) and meropenem-vaborbactam (MEM-VAB) against difficult-to-treat Enterobacterales infections. Our manuscript explores these antibiotics' pharmacokinetic and pharmacodynamic properties, antimicrobial activities, in vitro susceptibility testing, and clinical data. Moreover, it includes a meticulous examination of comparative clinical and microbiological studies, assessed and presented to provide clarity in making informed treatment choices for clinicians. Finally, we propose an expert opinion from a microbiological and a clinical point of view about their use in appropriate clinical settings. This is the first review aiming to provide healthcare professionals with valuable insights for making informed treatment decisions when combating carbapenem-resistant pathogens.

Pharmacokinetics of SPR206 in Plasma, Pulmonary Epithelial Lining Fluid, and Alveolar Macrophages following Intravenous Administration to Healthy Adult Subjects

SPR206 is a next-generation polymyxin being developed for the treatment of multidrug-resistant (MDR) Gram-negative infections. This Phase 1 bronchoalveolar lavage (BAL) study was conducted to evaluate SPR206's safety and pharmacokinetics in plasma, pulmonary epithelial lining fluid (ELF), and alveolar macrophages (AM) in healthy volunteers. Subjects received a 100 mg intravenous (IV) dose of SPR206 infused over 1 h every 8 h for 3 consecutive doses. Each subject underwent 1 bronchoscopy with BAL at 2, 3, 4, 6, or 8 h after the start of the third IV infusion. SPR206 concentrations in plasma, BAL, and cell pellet were measured with a validated LC-MS/MS assay. Thirty-four subjects completed the study and 30 completed bronchoscopies. Mean SPR206 peak concentrations (Cmax) in plasma, ELF, and AM were 4395.0, 735.5, and 860.6 ng/mL, respectively. Mean area under the concentration-time curve (AUC0-8) for SPR206 in plasma, ELF, and AM was 20120.7, 4859.8, and 6026.4 ng*h/mL, respectively. The mean ELF to unbound plasma concentration ratio was 0.264, and mean AM to unbound plasma concentration ratio was 0.328. Mean SPR206 concentrations in ELF achieved lung exposures above the MIC for target Gram-negative pathogens for the entire 8-h dosing interval. Overall, SPR206 was well tolerated; 22 subjects (64.7%) reported at least 1 treatment-emergent adverse event (TEAE). Of the 40 reported TEAEs, 34 (85.0%) were reported as mild in severity. The most frequent TEAEs were oral paresthesia (10 subjects [29.4%]) and nausea (2 subjects [5.9%]). This study demonstrates pulmonary penetration of SPR206 and supports further development of SPR206 for the treatment of patients with serious infections caused by MDR Gram-negative pathogens.

When and How to Use MIC in Clinical Practice?

Bacterial resistance to antibiotics continues to be a global public health problem. The choice of the most effective antibiotic and the use of an adapted dose in the initial phase of the infection are essential to limit the emergence of resistance. This will depend on (i) the isolated bacteria and its resistance profile, (ii) the pharmacodynamic (PD) profile of the antibiotic used and its level of toxicity, (iii) the site of infection, and (iv) the pharmacokinetic (PK) profile of the patient. In order to take account of both parameters to optimize the administered treatment, a minimal inhibitory concentration (MIC) determination associated with therapeutic drug monitoring (TDM) and their combined interpretation are required. The objective of this narrative review is thus to suggest microbiological, pharmacological, and/or clinical situations for which this approach could be useful. Regarding the microbiological aspect, such as the detection of antibiotic resistance and its level, the preservation of broad-spectrum β-lactams is particularly discussed. PK-PD profiles are relevant for difficult-to-reach infections and specific populations such as intensive care patients, cystic fibrosis patients, obese, or elderly patients. Finally, MIC and TDM are tools available to clinicians, who should not hesitate to use them to manage their patients.

Carbapenem-Resistant Gram-Negative Fermenting and Non-Fermenting Rods Isolated from Hospital Patients in Poland-What Are They Susceptible to?

Gram-negative fermenting and non-fermenting bacteria are important etiological factors of nosocomial and community infections, especially those that produce carbapenemases. Klebsiella pneumoniae, Acinetobacter baumannii, and Pseudomonas aeruginosa are the most frequently-detected carbapenemase-producing microorganisms. The predominant type of resistance is metallo-β-lactamase (MBL). These bacteria are predominantly isolated from bronchial alveolar lavage, urine, and blood. Carbapenemase-producing Enterobacterales (CPE) strains are always multi-drug-resistant. This significantly limits the treatment options for this type of infection, extends the time of patient hospitalization, and increases the risk of a more severe and complicated disease course. Preventing the transmission of these microorganisms should be a major public health initiative. New antibiotics and treatment regimens offer hope against these infections.