A Randomized Trial of the Amikacin Fosfomycin Inhalation System for the Adjunctive Therapy of Gram-Negative Ventilator-Associated Pneumonia

The efficacy and safety of inhaled antibiotics for pneumonia: A systematic review and meta-analysis

OBJECTIVES

The aim of this study was to evaluate the efficacy and safety of inhaled antibiotics for adults with pneumonia by meta-analysis.

METHODS

Literature retrieval was completed through five databases (PubMed, Embase, Cochrane Library, Web of Science and Scopus) by the deadline of May 31, 2024. The process of study selection and data extraction were performed independently by two reviewers. The quality of observational studies and randomized controlled trial (RCT) studies were evaluated by Newcastle Ottawa scale and Jadad scale, respectively. The primary outcomes included mortality, clinical cure, and microbiological cure. Secondary outcomes were recurrence and renal impairment.

RESULTS

There were 30 studies were analyzed, including 12 RCT studies and 18 observational studies. Inhaled antibiotics did not significantly reduce mortality in RCT studies (odds ratio (OR) = 1.06, 95 % confidence interval (CI): 0.80-1.41). Inhaled antibiotics were associated with higher rates of clinical cure (OR = 1.47 95%CI: 0.82-2.66 in RCT studies and OR = 2.09, 95%CI: 1.36-3.21 in observational studies) and microbiological cure (OR = 7.00 in RCT studies and OR = 2.20 in observational studies). Subgroup analysis showed patients received inhaled antibiotics combined with intravenous administration and inhaled amikacin had better improvements of mortality, clinical cure and microbiological cure. Inhaled antibiotics were not associated with recurrence. The pooled OR of renal impairment were 0.65 (95%CI: 0.27-1.13; I-squared = 43.5 %, P = 0.124) and 0.63(95%CI: 0.26-1.11; I-squared = 69.0 %, P = 0.110) in RCT studies and observational studies, respectively.

CONCLUSIONS

Inhaled antibiotics decreased risk of renal impairment and achieved significant improvements of clinical and microbiological cure in patients with pneumoniae.

Burden and Management of Multi-Drug Resistant Organism Infections in Solid Organ Transplant Recipients Across the World: A Narrative Review

Solid organ transplant (SOT) recipients are particularly susceptible to infections caused by multidrug-resistant organisms (MDRO) and are often the first to be affected by an emerging resistant pathogen. Unfortunately, their prevalence and impact on morbidity and mortality according to the type of graft is not systematically reported from high-as well as from low and middle-income countries (HIC and LMIC). Thus, epidemiology on MDRO in SOT recipients could be subjected to reporting bias. In addition, screening practices and diagnostic resources may vary between countries, as well as the availability of new drugs. In this review, we aimed to depict the burden of main Gram-negative MDRO in SOT patients across HIC and LMIC and to provide an overview of current diagnostic and therapeutic resources.

Management of Ventilator-Associated Pneumonia: Guidelines

Two recent major guidelines on diagnosis and treatment of ventilator-associated pneumonia (VAP) recommend consideration of local antibiotic resistance patterns and individual patient risks for resistant pathogens when formulating an initial empiric antibiotic regimen. One recommends against invasive diagnostic techniques with quantitative cultures to determine the cause of VAP; the other recommends either invasive or noninvasive techniques. Both guidelines recommend short-course therapy be used for most patients with VAP. Although neither guideline recommends use of procalcitonin as an adjunct to clinical judgment when diagnosing VAP, they differ with respect to use of serial procalcitonin to shorten the length of antibiotic treatment.

Optimization of an in vitro Pseudomonas aeruginosa Biofilm Model to Examine Antibiotic Pharmacodynamics at the Air-Liquid Interface

Pseudomonas aeruginosa is an important cause of lower respiratory tract infections, such as ventilator-associated bacterial pneumonia (VABP). Using inhaled antibiotics to treat VABP can achieve high drug concentrations at the infection site while minimizing systemic toxicities. Despite the theoretical advantages, clinical trials have failed to show a benefit for inhaled antibiotic therapy in treating VABP. A potential reason for this discordance is the presence of biofilm-embedded bacteria in lower respiratory tract infections. Drug selection and dosing are often based on data from bacteria grown planktonically. In the present study, an in vitro air-liquid interface pharmacokinetic/pharmacodynamic biofilm model was optimized to evaluate the activity of simulated epithelial lining fluid exposures of inhaled and intravenous doses of polymyxin B and tobramycin against two P. aeruginosa strains. Antibiotic activity was also determined against the P. aeruginosa strains grown planktonically. Our study revealed that inhaled antibiotic exposures were more active than their intravenous counterparts across biofilm and planktonic populations. Inhaled exposures of polymyxin B and tobramycin exhibited comparable activity against planktonic P. aeruginosa. Although inhaled polymyxin B exposures were initially more active against P. aeruginosa biofilms (through 6 h), tobramycin was more active by the end of the experiment (48 h). Together, these data slightly favor the use of inhaled tobramycin for VABP caused by biofilm-forming P. aeruginosa that are not resistant to either antibiotic. The optimized in vitro air-liquid interface pharmacokinetic/pharmacodynamic biofilm model may be beneficial for the development of novel anti-biofilm agents or to optimize antibiotic dosing for infections such as VABP.

Practical Lessons on Antimicrobial Therapy for Critically Ill Patients

Sepsis stands as a formidable global health challenge, with persistently elevated mortality rates in recent decades. Each year, sepsis not only contributes to heightened morbidity but also imposes substantial healthcare costs on survivors. This narrative review aims to highlight the targeted measures that can be instituted to alleviate the incidence and impact of sepsis in intensive care. Here we discuss measures to reduce nosocomial infections and the prevention of equipment and patient colonisation by resilient pathogens. The overarching global crisis of bacterial resistance to newly developed antimicrobial agents intensifies the imperative for antimicrobial stewardship and de-escalation. This urgency has been accentuated in recent years, notably during the COVID-19 pandemic, as high-dose steroids and opportunistic infections presented escalating challenges. Ongoing research into airway colonisation's role in influencing disease outcomes among critically ill patients underscores the importance of tailoring treatments to disease endotypes within heterogeneous populations, which are important lessons for intensivists in training. Looking ahead, the significance of novel antimicrobial delivery systems and drug monitoring is poised to increase. This narrative review delves into the multifaceted barriers and facilitators inherent in effectively treating critically ill patients vulnerable to nosocomial infections. The future trajectory of intensive care medicine hinges on the meticulous implementation of vigilant stewardship programs, robust infection control measures, and the continued exploration of innovative and efficient technological solutions within this demanding healthcare landscape.

How to treat severe Acinetobacter baumannii infections

PURPOSE OF REVIEW

To update the management of severe Acinetobacter baumannii infections (ABI), particularly those caused by multi-resistant isolates.

RECENT FINDINGS

The in vitro activity of the various antimicrobial agents potentially helpful in treating ABI is highly variable and has progressively decreased for many of them, limiting current therapeutic options. The combination of more than one drug is still advisable in most circumstances. Ideally, two active first-line drugs should be used. Alternatively, a first-line and a second-line drug and, if this is not possible, two or more second-line drugs in combination. The emergence of new agents such as Cefiderocol, the combination of Sulbactam and Durlobactam, and the new Tetracyclines offer therapeutic options that need to be supported by clinical evidence.

SUMMARY

The apparent limitations in treating infections caused by this bacterium, the rapid development of resistance, and the serious underlying situation in most cases invite the search for alternatives to antibiotic treatment, the most promising of which seems to be bacteriophage therapy.

Aminoglycosides for the Treatment of Severe Infection Due to Resistant Gram-Negative Pathogens

Aminoglycosides are a family of rapidly bactericidal antibiotics that often remain active against resistant Gram-negative bacterial infections. Over the past decade, their use in critically ill patients has been refined; however, due to their renal and cochleovestibular toxicity, their indications in the treatment of sepsis and septic shock have been gradually reduced. This article reviews the spectrum of activity, mode of action, and methods for optimizing the efficacy of aminoglycosides. We discuss the current indications for aminoglycosides, with an emphasis on multidrug-resistant Gram-negative bacteria, such as extended-spectrum β-lactamase-producing Enterobacterales, carbapenemase-producing Enterobacterales, multidrug-resistant Pseudomonas aeruginosa, and carbapenem-resistant Acinetobacter baumannii. Additionally, we review the evidence for the use of nebulized aminoglycosides.

Aerosolized Antibiotics to Manage Ventilator-Associated Infections: A Comprehensive Review

BACKGROUND

Ventilator-associated lower respiratory tract infectious complications in critically ill patients cover a wide spectrum of one disease process (respiratory infection), initiating from tracheal tube and/or tracheobronchial colonization, to ventilator associated tracheobronchitis (VAT) and ventilator-associated pneumonia (VAP). VAP occurence has been associated with increased intensive care unit (ICU) morbidity (ventilator days, as well as length of ICU and hospital stay) and ICU mortality. Therefore, treatments that aim at VAP/VAT incidence reduction are a high priority.

AIM

The aim of the present review is to discuss the current literature concerning two major aspects: (a) can aerosolized antibiotics (AA) administered in a pre-emptive way prevent the occurrence of ventilator-associated infections? and (b) can VAT treatment with aerosolized avert the potential evolution to VAP?

RESULTS

There were identified eight studies that provided data on the use of aerosolized antibiotics for the prevention of VAT/VAP. Most of them report favorable data on reducing the colonisation rate and the progression to VAP/VAT. Another four studies dealt with the treatment of VAT/VAP. The results support the decrease in the incidence to VAP transition and/or the improvement in signs and symptoms of VAP. Moreover, there are concise reports on higher cure rates and microbiological eradication in patients treated with aerosolized antibiotics. Yet, differences in the delivery modality adopted and resistance emergence issues preclude the generalisability of the results.

CONCLUSION

Aerosolized antibiotic therapy can be used to manage ventilator-associated infections, especially those with difficult to treat resistance. The limited clinical data raise the need for large randomized controlled trials to confirm the benefits of AA and to evaluate the impact on antibiotic selection pressure.

Advances in inhaled antibiotics for management of respiratory tract infections

PURPOSE OF REVIEW

The incidence of bacterial respiratory tract infections is growing. In a context of increasing antibiotic resistance and lack of new classes of antibiotics, inhaled antibiotics emerge as a promising therapeutic strategy. Although they are generally used for cystic fibrosis, their use in other conditions is becoming more frequent, including no-cystic fibrosis bronchiectasis, pneumonia and mycobacterial infections.

RECENT FINDINGS

Inhaled antibiotics exert beneficial microbiological effects in bronchiectasis and chronic bronchial infection. In nosocomial and ventilator-associated pneumonia, aerosolized antibiotics improve cure rates and bacterial eradication. In refractory Mycobacterium avium complex infections, amikacin liposome inhalation suspension is more effective in achieving long-lasting sputum conversion. In relation to biological inhaled antibiotics (antimicrobial peptides, interfering RNA and bacteriophages), currently in development, there is no still enough evidence that support their use in clinical practice.

SUMMARY

The effective antimicrobiological activity of inhaled antibiotics, added to their potential to overcoming resistances to systemic antibiotics, make inhaled antibiotics a plausible alternative.

Administration of Bacteriophages via Nebulization during Mechanical Ventilation: In Vitro Study and Lung Deposition in Macaques

Bacteriophages have been identified as a potential treatment option to treat lung infection in the context of antibiotic resistance. We performed a preclinical study to predict the efficacy of delivery of bacteriophages against Pseudomonas aeruginosa (PA) when administered via nebulization during mechanical ventilation (MV). We selected a mix of four anti-PA phages containing two Podoviridae and two Myoviridae, with a coverage of 87.8% (36/41) on an international PA reference panel. When administered via nebulization, a loss of 0.30–0.65 log of infective phage titers was measured. No difference between jet, ultrasonic and mesh nebulizers was observed in terms of loss of phage viability, but a higher output was measured with the mesh nebulizer. Interestingly, Myoviridae are significantly more sensitive to nebulization than Podoviridae since their long tail is much more prone to damage. Phage nebulization has been measured as compatible with humidified ventilation. Based on in vitro measurement, the lung deposition prediction of viable phage particles ranges from 6% to 26% of the phages loaded in the nebulizer. Further, 8% to 15% of lung deposition was measured by scintigraphy in three macaques. A phage dose of 1 × 109 PFU/mL nebulized by the mesh nebulizer during MV predicts an efficient dose in the lung against PA, comparable with the dose chosen to define the susceptibility of the strain.

Refractory Escherichia Coli Pneumonia: A Case Report

Escherichia (E.) coli pneumonia is a rare infection commonly presenting with a cavitary lesion. We report a case of a 44-year-old Hispanic male with comorbidities who was admitted to our facility with multiple falls for two days, shortness of breath, continuous diarrhea, and urinary urgency. Lab results showed leukocytosis with neutrophil predominance, anemia, and respiratory alkalosis. The patient was also noted to have uncontrolled diabetes mellitus with an A1c of 17.6%. Prior to admission to the medical intensive care unit (MICU), the patient was administered vancomycin and cefepime. The patient was then started on fluconazole while admitted to the MICU. In addition, a chest X-ray was conducted, showing patchy airspace opacities in the right upper lobe. A chest and abdominal CT also showed multiple cavitary lesions, pulmonary nodules, and nodular liver contour. Bronchoscopy with bronchoalveolar lavage conferred trimethoprim/sulfamethoxazole-resistant E. coli without fungal or acid-fast bacilli growth and was subsequently started on ampicillin/sulbactam. Infectious disease was consulted and advised to begin ertapenem. The patient developed increased respiratory demands and was subsequently started on mechanical ventilation with vasopressors. The patient was successfully weaned off and downgraded to the telemetry floor. The patient was successfully discharged in stable condition. This case highlights a severe and uncommon complication of E. coli infection causing pneumonia with cavitary lesions.

Inhaled amikacin for pneumonia treatment and dissemination prevention: an experimental model of severe monolateral Pseudomonas aeruginosa pneumonia

BACKGROUND

Pseudomonas aeruginosa pneumonia is commonly treated with systemic antibiotics to ensure adequate treatment of multidrug resistant (MDR) bacteria. However, intravenous (IV) antibiotics often achieve suboptimal pulmonary concentrations. We therefore aimed to evaluate the effect of inhaled amikacin (AMK) plus IV meropenem (MEM) on bactericidal efficacy in a swine model of monolateral MDR P. aeruginosa pneumonia.

METHODS

We ventilated 18 pigs with monolateral MDR P. aeruginosa pneumonia for up to 102 h. At 24 h after the bacterial challenge, the animals were randomized to receive 72 h of treatment with either inhaled saline (control), IV MEM only, or IV-MEM plus inhaled AMK (MEM + AMK). We dosed IV MEM at 25 mg/kg every 8 h and inhaled AMK at 400 mg every 12 h. The primary outcomes were the P. aeruginosa burden and histopathological injury in lung tissue. Secondary outcomes included the P. aeruginosa burden in tracheal secretions and bronchoalveolar lavage fluid, the development of antibiotic resistance, the antibiotic distribution, and the levels of inflammatory markers.

RESULTS

The median (25-75th percentile) P. aeruginosa lung burden for animals in the control, MEM only, and MEM + AMK groups was 2.91 (1.75-5.69), 0.72 (0.12-3.35), and 0.90 (0-4.55) log10 CFU/g (p = 0.009). Inhaled therapy had no effect on preventing dissemination compared to systemic monotherapy, but it did have significantly higher bactericidal efficacy in tracheal secretions only. Remarkably, the minimum inhibitory concentration of MEM increased to > 32 mg/L after 72-h exposure to monotherapy in 83% of animals, while the addition of AMK prevented this increase (p = 0.037). Adjunctive therapy also slightly affected interleukin-1β downregulation. Despite finding high AMK concentrations in pulmonary samples, we found no paired differences in the epithelial lining fluid concentration between infected and non-infected lungs. Finally, a non-significant trend was observed for higher amikacin penetration in low-affected lung areas.

CONCLUSIONS

In a swine model of monolateral MDR P. aeruginosa pneumonia, resistant to the inhaled AMK and susceptible to the IV antibiotic, the use of AMK as an adjuvant treatment offered no benefits for either the colonization of pulmonary tissue or the prevention of pathogen dissemination. However, inhaled AMK improved bacterial eradication in the proximal airways and hindered antibiotic resistance.

How to Use Nebulized Antibiotics in Severe Respiratory Infections

Difficult-to-treat pulmonary infections caused by multidrug-resistant (MDR) pathogens are of great concern because their incidence continues to increase worldwide and they are associated with high morbidity and mortality. Nebulized antibiotics are increasingly being used in this context. The advantages of the administration of a nebulized antibiotic in respiratory tract infections due to MDR include the potential to deliver higher drug concentrations to the site of infection, thus minimizing the systemic adverse effects observed with the use of parenteral or oral antibiotic agents. However, there is an inconsistency between the large amount of experimental evidence supporting the administration of nebulized antibiotics and the paucity of clinical studies confirming the efficacy and safety of these drugs. In this narrative review, we describe the current evidence on the use of nebulized antibiotics for the treatment of severe respiratory infections.

Pseudomonas aeruginosa: Infections, Animal Modeling, and Therapeutics

Pseudomonas aeruginosa is an important Gram-negative opportunistic pathogen which causes many severe acute and chronic infections with high morbidity, and mortality rates as high as 40%. What makes P. aeruginosa a particularly challenging pathogen is its high intrinsic and acquired resistance to many of the available antibiotics. In this review, we review the important acute and chronic infections caused by this pathogen. We next discuss various animal models which have been developed to evaluate P. aeruginosa pathogenesis and assess therapeutics against this pathogen. Next, we review current treatments (antibiotics and vaccines) and provide an overview of their efficacies and their limitations. Finally, we highlight exciting literature on novel antibiotic-free strategies to control P. aeruginosa infections.

Treatment of Acinetobacter baumannii severe infections

Acinetobacter baumannii is a Gram-negative, multidrug-resistant (MDR) pathogen that causes nosocomial infections, especially in intensive care units (ICUs) and immunocompromised patients. A. baumannii has developed a broad spectrum of antimicrobial resistance, associated with a higher mortality rate among infected patients compared with other non-baumannii species. In terms of clinical impact, resistant strains are associated with increases in both in-hospital length of stay and mortality. A. baumannii can cause a variety of infections, especially ventilator-associated pneumonia, bacteremia, and skin wound infections, among others. The most common risk factors for the acquisition of MDR A. baumannii are previous antibiotic use, mechanical ventilation, length of ICU and hospital stay, severity of illness, and use of medical devices. Current efforts are focused on addressing all the antimicrobial resistance mechanisms described in A. baumannii, with the objective of identifying the most promising therapeutic scheme.

Pharmacokinetic Characteristics of Nebulized Colistimethate Sodium Using Two Different Types of Nebulizers in Critically Ill Patients with Ventilator-Associated Respiratory Infections

Background: Rising antimicrobial resistance has led to a revived interest in inhaled colistin treatment in the critically ill patient with ventilator-associated respiratory infection (VARI). Nebulization via vibrating mesh nebulizers (VMNs) is considered the current standard-of-care, yet the use of generic jet nebulizers (JNs) is more widespread. Few data exist on the intrapulmonary pharmacokinetics of colistin when administered through VMNs, while there is a complete paucity regarding the use of JNs. Methods: In this study, 18 VARI patients who received 2 million international units of inhaled colistimethate sodium (CMS) through a VMN were pharmacokinetically compared with six VARI patients who received the same drug dose through a JN, in the absence of systemic CMS administration. Results: Surprisingly, VMN and JN led to comparable formed colistin exposures in the epithelial lining fluid (ELF) (median (IQR) AUC0-24: 86.2 (46.0-185.9) mg/L∙h with VMN and 91.5 (78.1-110.3) mg/L∙h with JN). The maximum ELF concentration was 10.4 (4.7-22.6) mg/L and 7.4 (6.2-10.3) mg/L, respectively. Conclusions: Based on our results, JN might be considered a viable alternative to the theoretically superior VMN. Therapeutic drug monitoring in the ELF can be advised due to the observed low exposure, high variability, and appreciable systemic absorption.

Nosocomial Pneumonia in the Mechanically Ventilated Patient

Ventilator-associated pneumonia (VAP) is a common complication occurring in critically ill patients who are mechanically ventilated and is the leading cause of nosocomial infection-related death. Etiologic agents for VAP widely differ based on the population of intensive care unit patients, duration of hospital stay, and prior antimicrobial therapy. VAP due to multidrug-resistant pathogens is associated with the highest morbidity and mortality, likely due to delays in appropriate antimicrobial treatment. International guidelines are currently available to guide diagnostic and therapeutic strategies. VAP can be prevented through various pharmacological and non-pharmacological interventions, which are more effective when grouped as bundles. When VAP is clinically suspected, diagnostic strategies should include early collection of respiratory samples to guide antimicrobial therapy. Empirical treatment should be based on the most likely etiologic microorganisms and antibiotics likely to be active against these microorganisms. Response to therapy should be reassessed after 3 to 5 days and antimicrobials adjusted or de-escalated to reduce the burden of the disease. Finally, considering that drug resistance is increasing worldwide, several novel antibiotics are being tested to efficiently treat VAP in the coming decades.

Aerosol therapy during mechanical ventilation in intensive care units: A questionnaire-based survey of 2203 ICU medical staff in China

Background

To describe the current status of aerosol therapy during mechanical ventilation (MV) and the practice, knowledge, and beliefs about aerosol therapy in physicians working in the intensive care unit (ICU) in China.

Methods

A physician self-administered questionnaire-based cross-sectional survey was carried out from January 2019 to July 2019. An electronic questionnaire was designed, and physicians who worked regularly in ICUs across several hospitals were contacted through WeChat. Answers to all questions and the general characteristics of physicians who answered the questionnaire were collected and analyzed.

Results

A total of 2203 medical staff who regularly worked in the ICUs completed this questionnaire (9.0% missing data); 87.7% of the participants were doctors. Most respondents claimed that they often administered aerosolization therapy. Ultrasonic atomizer (50.7%) and jet nebulizer (48.6%) were the most commonly used atomization devices. Bronchodilators (65.8%) and steroids (66.3%) were the most frequently aerosolized drugs during MV. During nebulization, ventilator settings were never changed by 32.7% of respondents. Only 49.1% of respondents knew the appropriate place for a nebulizer. Further, 62.7% of respondents using heated humidifiers reported turning them off during nebulization. Specific knowledge about droplet size and nebulization yield was poor. Respondents from tertiary hospitals and those with higher technical title or work experience tended to have better accuracy than those from primary hospitals or with lower technical titles (P < 0.050).

Conclusions

Aerosol therapy was commonly used during MV, and the most frequent drugs were bronchodilators and steroids. Scientific knowledge about the optimal implementation of aerosol therapy during MV seemed deficient.

Combination of in vivo phage therapy data with in silico model highlights key parameters for pneumonia treatment efficacy

The clinical (re)development of bacteriophage (phage) therapy to treat antibiotic-resistant infections faces the challenge of understanding the dynamics of phage-bacteria interactions in the in vivo context. Here, we develop a general strategy coupling in vitro and in vivo experiments with a mathematical model to characterize the interplay between phage and bacteria during pneumonia induced by a pathogenic strain of Escherichia coli. The model allows the estimation of several key parameters for phage therapeutic efficacy. In particular, it quantifies the impact of dose and route of phage administration as well as the synergism of phage and the innate immune response on bacterial clearance. Simulations predict a limited impact of the intrinsic phage characteristics in agreement with the current semi-empirical choices of phages for compassionate treatments. Model-based approaches will foster the deployment of future phage-therapy clinical trials.

Ventilator-associated pneumonia in critically ill patients with COVID-19 infection, a narrative review

COVID pneumonitis can cause patients to become critically ill. They may require intensive care and mechanical ventilation. Ventilator-associated pneumonia is a concern. This review aims to discuss the topic of ventilator-associated pneumonia in this group. Several reasons have been proposed to explain the elevated rates of VAP in critically ill COVID patients compared to non-COVID patients. Extrinsic factors include understaffing, lack of PPE and use of immunomodulating agents. Intrinsic factors include severe parenchymal damage, immune dysregulation, along with pulmonary vascular endothelial inflammation and thrombosis. The rate of VAP has been reported at 45.4%, with an ICU mortality rate of 42.7%. Multiple challenges to diagnosis exist. Other conditions such as acute respiratory distress syndrome, pulmonary oedema and atelectasis can present with similar features. Frequent growth of gram-negative bacteria has been shown in multiple studies, with particularly high rates of pseudomonas aeruginosa. The rate of invasive pulmonary aspergillosis has been reported at 4–30%. We would recommend the use of invasive techniques when possible. This will enable de-escalation of antibiotics as soon as possible, decreasing overuse. It is also important to keep other possible causes of ventilator-associated pneumonia in mind, such as COVID-19 associated pulmonary aspergillosis, cytomegalovirus, etc. Diagnostic tests such as galactomannan and B-D-glucan should be considered. These patients may face a long treatment course, with risk of re-infection, along with prolonged weaning, which carries its own long-term consequences.

Infectious Diseases Society of America 2022 Guidance on the Treatment of Extended-Spectrum β-lactamase Producing Enterobacterales (ESBL-E), Carbapenem-Resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with Difficult-to-Treat Resistance (DTR-P. aeruginosa)

BACKGROUND

The Infectious Diseases Society of America (IDSA) is committed to providing up-to-date guidance on the treatment of antimicrobial-resistant infections. The initial guidance document on infections caused by extended-spectrum β-lactamase producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with difficult-to-treat resistance (DTR-P. aeruginosa) was published on 17 September 2020. Over the past year, there have been a number of important publications furthering our understanding of the management of ESBL-E, CRE, and DTR-P. aeruginosa infections, prompting a rereview of the literature and this updated guidance document.

METHODS

A panel of 6 infectious diseases specialists with expertise in managing antimicrobial-resistant infections reviewed, updated, and expanded previously developed questions and recommendations about the treatment of ESBL-E, CRE, and DTR-P. aeruginosa infections. Because of differences in the epidemiology of resistance and availability of specific anti-infectives internationally, this document focuses on the treatment of infections in the United States.

RESULTS

Preferred and alternative treatment recommendations are provided with accompanying rationales, assuming the causative organism has been identified and antibiotic susceptibility results are known. Approaches to empiric treatment, duration of therapy, and other management considerations are also discussed briefly. Recommendations apply for both adult and pediatric populations.

CONCLUSIONS

The field of antimicrobial resistance is highly dynamic. Consultation with an infectious diseases specialist is recommended for the treatment of antimicrobial-resistant infections. This document is current as of 24 October 2021. The most current versions of IDSA documents, including dates of publication, are available at www.idsociety.org/practice-guideline/amr-guidance/.

Treatment of ventilator-associated pneumonia due to carbapenem-resistant Gram-negative bacteria with novel agents: a contemporary, multidisciplinary ESGCIP perspective

INTRODUCTION

: In the past 15 years, treatment of VAP caused by carbapenem-resistant Gram-negative bacteria (CR-GNB) has represented an intricate challenge for clinicians.

AREAS COVERED

In this perspective article, we discuss the available clinical data about novel agents for the treatment of CR-GNB VAP, together with general PK/PD principles for the treatment of VAP, in the attempt to provide some suggestions for optimizing antimicrobial therapy of CR-GNB VAP in the daily clinical practice.

EXPERT OPINION

Recently, novel BL and BL/BLI combinations have become available that have shown potent in vitro activity against CR-GNB and have attracted much interest as novel, less toxic, and possibly more efficacious options for the treatment of CR-GNB VAP compared with previous standard of care. Besides randomized controlled trials, a good solution to enrich our knowledge on how to use these novel agents at best in the near future, while at the same time remaining adherent to current evidence-based guidelines, is to improve our collaboration to conduct larger multinational observational studies to collect sufficiently large populations treated in real life with those novel agents for which guidelines currently do not provide a recommendation (in favor or against) for certain causative organisms.

Carbapenem-resistant Acinetobacter baumannii: Colonization, Infection and Current Treatment Options

Carbapenem-resistant Acinetobacter baumannii (CRAB) causes colonization and infection predominantly in hospitalized patients. Distinction between the two is a challenge. When CRAB is isolated from a non-sterile site (soft tissue, respiratory samples, etc.), it probably represents colonization unless clear signs of infection (fever, elevated white blood count, elevated inflammatory markers and abnormal imaging) are present. Treatment is warranted only for true infections. In normally sterile sites (blood, cerebrospinal fluid) the presence of indwelling medical devices (catheters, stents) should be considered when evaluating positive cultures. In the absence of such devices, the isolate represents an infection and should be treated. If an indwelling device is present and there are no signs of active infection, the device should be replaced if possible, and no treatment is required. If there are signs of an active infection the device should be removed or replaced, and treatment should be administered. Current treatments options and clinical data are limited. No agent or combination regimen has been shown to be superior to any other in randomized clinical trials. Ampicillin-sulbactam appears to have the best evidence for initial use. This is probably due to its ability to saturate penicillin-binding proteins 1 and 3 when given in high dose. Tigecycline when used should be given in high dose as well. Polymyxins are a treatment option but are difficult to dose correctly and have significant side effects. Newer treatment options such as eravacycline and cefiderocol have potential; however, currently there are not enough data to support their use as single agents. Combination therapy appears to be the best treatment option and should always include high-dose ampicillin-sulbactam combined with another active agent such as high-dose tigecycline, polymyxins, etc. These infections require a high complexity of skill, and an infectious disease specialist should be involved in the management of these patients.

How to use new antibiotics in the therapy of ventilator-associated pneumonia

PURPOSE OF REVIEW

Ventilator-associated pneumonia (VAP) is a common nosocomial infection in critically ill patients requiring endotracheal intubation and mechanical ventilation. Recently, the emergence of multidrug-resistant Gram-negative bacteria, including carbapenem-resistant Enterobacterales, multidrug-resistant Pseudomonas aeruginosa and Acinetobacter species, has complicated the selection of appropriate antimicrobials and contributed to treatment failure. Although novel antimicrobials are crucial to treating VAP caused by these multidrug-resistant organisms, knowledge of how to optimize their efficacy while minimizing the development of resistance should be a requirement for their use.

RECENT FINDINGS

Several studies have assessed the efficacy of novel antimicrobials against multidrug-resistant organisms, but high-quality studies focusing on optimal dosing, infusion time and duration of therapy in patients with VAP are still lacking. Antimicrobial and diagnostic stewardship should be combined to optimize the use of these novel agents.

SUMMARY

Improvements in diagnostic tests, stewardship practices and a better understanding of dosing, infusion time, duration of treatment and the effects of combining various antimicrobials should help optimize the use of novel antimicrobials for VAP and maximize clinical outcomes while minimizing the development of resistance.

The Unfulfilled Promise of Inhaled Therapy in Ventilator-Associated Infections: Where Do We Go from Here?

Respiratory infection is common in intubated/tracheotomized patients and systemic antibiotic therapy is often unrewarding. In 1967, the difficulty in treating Gram-negative respiratory infections led to the use of inhaled gentamicin, targeting therapy directly to the lungs. Fifty-three years later, the effects of topical therapy in the intubated patient remain undefined. Clinical failures with intravenous antibiotics persist and instrumented patients are now infected by many more multidrug-resistant Gram-negative species as well as methicillin-resistant Staphylococcus aureus. Multiple systematic reviews and meta-analyses suggest that there may be a role for inhaled delivery but “more research is needed.” Yet there is still no Food and Drug Administration (FDA) approved inhaled antibiotic for the treatment of ventilator-associated infection, the hallmark of which is the foreign body in the upper airway. Current pulmonary and infectious disease guidelines suggest using aerosols only in the setting of Gram-negative infections that are resistant to all systemic antibiotics or not to use them at all. Recently two seemingly well-designed large randomized placebo-controlled Phase 2 and Phase 3 clinical trials of adjunctive inhaled therapy for the treatment of ventilator-associated pneumonia failed to show more rapid resolution of pneumonia symptoms or effect on mortality. Despite evolving technology of delivery devices and more detailed understanding of the factors affecting delivery, treatment effects were no better than placebo. What is wrong with our approach to ventilator- associated infection? Is there a message from the large meta-analyses and these two large recent multisite trials? This review will suggest why current therapies are unpredictable and have not fulfilled the promise of better outcomes. Data suggest that future studies of inhaled therapy, in the milieu of worsening bacterial resistance, require new approaches with completely different indications and endpoints to determine whether inhaled therapy indeed has an important role in the treatment of ventilated patients.

New Antibiotics for Hospital-Acquired Pneumonia and Ventilator-Associated Pneumonia

Hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP) represent one of the most common hospital-acquired infections, carrying a significant morbidity and risk of mortality. Increasing antibiotic resistance among the common bacterial pathogens associated with HAP and VAP, especially Enterobacterales and nonfermenting gram-negative bacteria, has made the choice of empiric treatment of these infections increasingly challenging. Moreover, failure of initial empiric therapy to cover the causative agents associated with HAP and VAP has been associated with worse clinical outcomes. This review provides an overview of antibiotics newly approved or in development for the treatment of HAP and VAP. The approved antibiotics include ceftobiprole, ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, imipenem-relebactam, and cefiderocol. Their major advantages include their high activity against multidrug-resistant gram-negative pathogens.

Treatment of Severe Infections Due to Metallo-Betalactamases Enterobacterales in Critically Ill Patients

Metallo-beta-lactamases-producing (MBL) Enterobacterales is a growing problem worldwide. The optimization of antibiotic therapy is challenging. The pivotal available therapeutic options are either the combination of ceftazidime/avibactam and aztreonam or cefiderocol. Colistin, fosfomycin, tetracyclines and aminoglycosides are also frequently effective in vitro, but are associated with less bactericidal activity or more toxicity. Prior to the availability of antibiotic susceptibility testing, severe infections should be treated with a combination therapy. A careful optimization of the pharmacokinetic/pharmacodynamic properties of antimicrobials is instrumental in severe infections. The rules of antibiotic therapy are also reported and discussed. To conclude, treatment of severe MBL infections in critically ill patients is difficult. It should be individualized with a close collaboration of intensivists with microbiologists, pharmacists and infection control practitioners.

Nebulized Antibiotics for Healthcare- and Ventilator-Associated Pneumonia

Global emergence of multidrug-resistant and extensive drug-resistant gram-negative bacteria has increased the risk of treatment failure, especially for healthcare- or ventilator-associated pneumonia (HAP/VAP). Nebulization of antibiotics, by providing high intrapulmonary antibiotic concentrations, represents a promising approach to optimize the treatment of HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria, while limiting systemic antibiotic exposure. Aminoglycosides and colistin methanesulfonate are the most common nebulized antibiotics. Although optimal nebulized drug dosing regimen is not clearly established, high antibiotic doses should be administered using vibrating-mesh nebulizer with optimized ventilator settings to ensure safe and effective intrapulmonary concentrations. When used preventively, nebulized antibiotics reduced the incidence of VAP without any effect on mortality. This approach is not yet recommended and large randomized controlled trials should be conducted to confirm its benefit and explore the impact on antibiotic selection pressure. Compared with high-dose intravenous administration, high-dose nebulized colistin methanesulfonate seems to be more effective and safer in the treatment of ventilator-associated tracheobronchitis and VAP caused by multidrug resistant and extensive-drug resistant gram-negative bacteria. Adjunctive nebulized aminoglycosides could increase the clinical cure rate and bacteriological eradication in patients suffering from HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria. As nebulized aminoglycosides broadly diffuse in the systemic circulation of patients with extensive bronchopneumonia, monitoring of plasma trough concentrations is recommended during the period of nebulization. Large randomized controlled trials comparing high dose of nebulized colistin methanesulfonate to high dose of intravenous colistin methanesulfonate or to intravenous new β-lactams in HAP/VAP due to multidrug-resistant and extensive drug-resistant gram-negative bacteria are urgently needed.

Aerosolized antibiotics in the treatment of hospital-acquired pneumonia/ventilator-associated pneumonia

Aerosolized antibiotics are being increasingly used to treat respiratory infections, especially those caused by drug-resistant pathogens. Their use in the treatment of hospital-acquired pneumonia and ventilator-associated pneumonia in critically ill patients is especially significant. They are also used as an efficient alternative to overcome the issues caused by systemic administration of antibiotics, including the occurrence of drug-resistant strains, drug toxicity, and insufficient drug concentration at the target site. However, the rationale for the use of aerosolized antibiotics is limited owing to their insufficient efficacy and the potential for underestimated risks of developing side effects. Despite the lack of availability of high-quality evidence, the use of aerosolized antibiotics is considered as an attractive alternative treatment approach, especially in patients with multidrug-resistant pathogens. In this review, we have discussed the effectiveness and side effects of aerosolized antibiotics as well as the latest advancements in this field and usage in the Republic of Korea.

Management of pneumonia in critically ill patients

Severe pneumonia is associated with high mortality (short and long term), as well as pulmonary and extrapulmonary complications. Appropriate diagnosis and early initiation of adequate antimicrobial treatment for severe pneumonia are crucial in improving survival among critically ill patients. Identifying the underlying causative pathogen is also critical for antimicrobial stewardship. However, establishing an etiological diagnosis is challenging in most patients, especially in those with chronic underlying disease; those who received previous antibiotic treatment; and those treated with mechanical ventilation. Furthermore, as antimicrobial therapy must be empiric, national and international guidelines recommend initial antimicrobial treatment according to the location's epidemiology; for patients admitted to the intensive care unit, specific recommendations on disease management are available. Adherence to pneumonia guidelines is associated with better outcomes in severe pneumonia. Yet, the continuing and necessary research on severe pneumonia is expansive, inviting different perspectives on host immunological responses, assessment of illness severity, microbial causes, risk factors for multidrug resistant pathogens, diagnostic tests, and therapeutic options.

Infectious Diseases Society of America Guidance on the Treatment of AmpC β-lactamase-Producing Enterobacterales, Carbapenem-Resistant Acinetobacter baumannii, and Stenotrophomonas maltophilia Infections

BACKGROUND

The Infectious Diseases Society of America (IDSA) is committed to providing up-to-date guidance on the treatment of antimicrobial-resistant infections. A previous guidance document focused on infections caused by extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E), carbapenem-resistant Enterobacterales (CRE), and Pseudomonas aeruginosa with difficult-to-treat resistance (DTR-P. aeruginosa). Here, guidance is provided for treating AmpC β-lactamase-producing Enterobacterales (AmpC-E), carbapenem-resistant Acinetobacter baumannii (CRAB), and Stenotrophomonas maltophilia infections.

METHODS

A panel of six infectious diseases specialists with expertise in managing antimicrobial-resistant infections formulated questions about the treatment of AmpC-E, CRAB, and S. maltophilia infections. Answers are presented as suggestions and corresponding rationales. In contrast to guidance in the previous document, published data on optimal treatment of AmpC-E, CRAB, and S. maltophilia infections are limited. As such, guidance in this document is provided as "suggested approaches" based on clinical experience, expert opinion, and a review of the available literature. Because of differences in the epidemiology of resistance and availability of specific anti-infectives internationally, this document focuses on the treatment of infections in the United States.

RESULTS

Preferred and alternative treatment suggestions are provided, assuming the causative organism has been identified and antibiotic susceptibility results are known. Approaches to empiric treatment, duration of therapy, and other management considerations are also discussed briefly. Suggestions apply for both adult and pediatric populations.

CONCLUSIONS

The field of antimicrobial resistance is highly dynamic. Consultation with an infectious diseases specialist is recommended for the treatment of antimicrobial-resistant infections. This document is current as of September 17, 2021 and will be updated annually. The most current versions of IDSA documents, including dates of publication, are available at www.idsociety.org/practice-guideline/amr-guidance-2.0/.

Expanding clinical phage microbiology: simulating phage inhalation for respiratory tract infections

Phage therapy is a promising antibacterial strategy for resistant respiratory tract infections. Phage inhalation may serve this goal; however, it requires a careful assessment of their delivery by this approach. Here we present an in vitro model to evaluate phage inhalation. Eight phages, most of which target pathogens common in cystic fibrosis, were aerosolised by jet nebuliser and administered to a real-scale computed tomography-derived 3D airways model with a breathing simulator. Viable phage loads reaching the output of the nebuliser and the tracheal level of the model were determined and compared to the loaded amount. Phage inhalation resulted in a diverse range of titre reduction, primarily associated with the nebulisation process. No correlation was found between phage delivery to the phage physical or genomic dimensions. These findings highlight the need for tailored simulations of phage delivery, ideally by a patient-specific model in addition to proper phage matching, to increase the potential of phage therapy success.

Inhaled amikacin versus placebo to prevent ventilator-associated pneumonia: the AMIKINHAL double-blind multicentre randomised controlled trial protocol

INTRODUCTION

Pre-emptive inhaled antibiotics may be effective to reduce the occurrence of ventilator-associated pneumonia among critically ill patients. Meta-analysis of small sample size trials showed a favourable signal. Inhaled antibiotics are associated with a reduced emergence of antibiotic resistant bacteria. The aim of this trial is to evaluate the benefit of a 3-day course of inhaled antibiotics among patients undergoing invasive mechanical ventilation for more than 3 days on the occurrence of ventilator-associated pneumonia.

METHODS AND ANALYSIS

Academic, investigator-initiated, parallel two group arms, double-blind, multicentre superiority randomised controlled trial. Patients invasively ventilated more than 3 days will be randomised to receive 20 mg/kg inhaled amikacin daily for 3 days or inhaled placebo (0.9% Sodium Chloride). Occurrence of ventilator-associated pneumonia will be recorded based on a standardised diagnostic framework from randomisation to day 28 and adjudicated by a centralised blinded committee.

ETHICS AND DISSEMINATION

The protocol and amendments have been approved by the regional ethics review board and French competent authorities (Comité de protection des personnes Ouest I, No.2016-R29). All patients will be included after informed consent according to French law. Results will be disseminated in international scientific journals.

TRIAL REGISTRATION NUMBERS

EudraCT 2016-001054-17 and NCT03149640.

Nebulized antibiotics for ventilator-associated pneumonia: methodological framework for future multicenter randomized controlled trials

PURPOSE OF REVIEW

Although experimental evidence supports the use of nebulized antibiotics in ventilator-associated pneumonia (VAP), two recent multicenter randomized controlled trials (RCTs) have failed to demonstrate any benefit in VAP caused by Gram-negative bacteria (GNB). This review examines the methodological requirements concerning future RCTs.

RECENT FINDINGS

High doses of nebulized antibiotics are required to reach the infected lung parenchyma. Breath-synchronized nebulizers do not allow delivery of high doses. Mesh nebulizers perform better than jet nebulizers. Epithelial lining fluid concentrations do not reflect interstitial lung concentrations in patients receiving nebulized antibiotics. Specific ventilator settings for optimizing lung deposition require sedation to avoid patient's asynchrony with the ventilator.

SUMMARY

Future RCTs should compare a 3-5 day nebulization of amikacin or colistimethate sodium (CMS) to a 7-day intravenous administration of a new cephalosporine/ß-lactamase inhibitor. Inclusion criteria should be a VAP or ventilator-associated tracheobronchitis caused by documented extensive-drug or pandrug resistant GNB. If the GNB remains susceptible to aminoglycosides, nebulized amikacin should be administered at a dose of 40 mg/kg/day. If resistant to aminoglycosides, nebulized CMS should be administered at a dose of 15 millions international units (IU)/day. In VAP caused by pandrug-resistant GNB, 15 millions IU/day nebulized CMS (substitution therapy) should be compared with a 9 millions IU/day intravenous CMS.

Escalating antimicrobial resistance among Enterobacteriaceae: focus on carbapenemases

Introduction: Over the past few decades, antimicrobial resistance (AMR) has skyrocketed globally among bacteria within the Family Enterobacteriaceae (i.e. Enterobacter spp, Klebsiella spp, Escherichia coli, Proteus spp, Serratia marcescens, Citrobacter spp, and others). Enterobacteriaceae are intestinal flora and are important pathogens in nosocomial and community settings. Enterobacteriaceae spread easily between humans and may acquire AMR via plasmids or other mobile resistance elements. The emergence and spread of multidrug resistant (MDR) clones have greatly limited therapeutic options. Some infections are untreatable with existing antimicrobials.Areas covered: The authors discuss the escalation of CRE globally, the epidemiology and outcomes of CRE infections, the optimal therapy, and the potential role of several new antimicrobials to combat MDR organisms. An exhaustive search for literature related to Enterobacteriaceae was performed using PubMed, using the following key words: antimicrobial resistance; carbapenemases; Enterobacterales; Enterobacteriaceae; Klebsiella pneumoniae; Escherichia coli; global epidemiology; metallo-β-lactamases; multidrug resistance; New Delhi Metalloproteinase-1 (NDM-1); plasmidsExpert opinion: Innovation and development of new classes of antibacterial agents are critical to expand effective therapeutic options. The authors encourage the judicious use of antibiotics and aggressive infection-control measures are essential to minimize the spread of AMR.

Inhaled bacteriophage therapy in a porcine model of pneumonia caused by Pseudomonas aeruginosa during mechanical ventilation

BACKGROUND AND PURPOSE 255: Pseudomonas aeruginosa is a main cause of ventilator-associated pneumonia (VAP) with drug-resistant bacteria. Bacteriophage therapy has experienced resurgence to compensate for the limited development of novel antibiotics. However, phage therapy is limited to a compassionate use so far, resulting from lack of adequate studies in relevant pharmacological models. We used a pig model of pneumonia caused by P. aeruginosa that recapitulates essential features of human disease to study the antimicrobial efficacy of nebulized-phage therapy.

EXPERIMENTAL APPROACH

(i) Lysis kinetic assays were performed to evaluate in vitro phage antibacterial efficacy against P. aeruginosa and select relevant combinations of lytic phages. (ii) The efficacy of the phage combinations was investigated in vivo (murine model of P. aeruginosa lung infection). (iii) We determined the optimal conditions to ensure efficient phage delivery by aerosol during mechanical ventilation. (iv) Lung antimicrobial efficacy of inhaled-phage therapy was evaluated in pigs, which were anaesthetized, mechanically ventilated and infected with P. aeruginosa.

KEY RESULTS

By selecting an active phage cocktail and optimizing aerosol delivery conditions, we were able to deliver high phage concentrations in the lungs, which resulted in a rapid and marked reduction in P. aeruginosa density (1.5-log reduction, p < .001). No infective phage was detected in the sera and urines throughout the experiment.

CONCLUSION AND IMPLICATIONS

Our findings demonstrated (i) the feasibility of delivering large amounts of active phages by nebulization during mechanical ventilation and (ii) rapid control of in situ infection by inhaled bacteriophage in an experimental model of P. aeruginosa pneumonia with high translational value.

Optimizing Antimicrobial Drug Dosing in Critically Ill Patients

A fundamental step in the successful management of sepsis and septic shock is early empiric antimicrobial therapy. However, for this to be effective, several decisions must be addressed simultaneously: (1) antimicrobial choices should be adequate, covering the most probable pathogens; (2) they should be administered in the appropriate dose, (3) by the correct route, and (4) using the correct mode of administration to achieve successful concentration at the infection site. In critically ill patients, antimicrobial dosing is a common challenge and a frequent source of errors, since these patients present deranged pharmacokinetics, namely increased volume of distribution and altered drug clearance, which either increased or decreased. Moreover, the clinical condition of these patients changes markedly over time, either improving or deteriorating. The consequent impact on drug pharmacokinetics further complicates the selection of correct drug schedules and dosing during the course of therapy. In recent years, the knowledge of pharmacokinetics and pharmacodynamics, drug dosing, therapeutic drug monitoring, and antimicrobial resistance in the critically ill patients has greatly improved, fostering strategies to optimize therapeutic efficacy and to reduce toxicity and adverse events. Nonetheless, delivering adequate and appropriate antimicrobial therapy is still a challenge, since pathogen resistance continues to rise, and new therapeutic agents remain scarce. We aim to review the available literature to assess the challenges, impact, and tools to optimize individualization of antimicrobial dosing to maximize exposure and effectiveness in critically ill patients.

Effectiveness and safety of adjunctive inhaled antibiotics for ventilator-associated pneumonia: A systematic review and meta-analysis of randomized controlled trials

INTRODUCTION

The efficacy and safety of adjunctive inhaled antibiotic therapy for ventilator-associated pneumonia (VAP) was systematically reviewed based on updated studies.

METHODS

We searched four databases and four clinical trial registration platforms to identify relevant studies published prior to May 19, 2020. Randomized controlled trials (RCTs) assessing adjunctive antibiotic inhalation treatment for VAP patients were eligible for this review. Two reviewers independently screened the articles and extracted the data. Information on inhaled therapy and clinical outcomes was collected. Study quality was assessed with the Cochrane risk of bias tool. The meta-analysis was conducted with Review Manager and R software. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) guidelines were used to evaluate the quality of evidence for each pooled outcome.

RESULTS

Eleven RCTs and 1210 patients were included in this analysis after the application of the inclusion and exclusion criteria. Compared with the use of intravenous injection alone, the use of adjunctive inhaled antibiotic therapy improved the rates of clinical cure (relative risk (RR) 1.13, 95% CI [1.02,1.26]) and microbiological eradication (RR 1.45, 95% CI [1.19,1.76]) in VAP patients. However, despite these improvements, mortality was not reduced (RR 1.00, 95% CI [0.82,1.21]). Adjunctive antibiotics delivered through the respiratory tract were not associated with a higher risk of renal impairment but were associated with an increased risk of bronchospasm (RR 2.74, 95% CI [1.31,5.73] during treatment.

CONCLUSIONS

Adjunctive inhaled antibiotics improved the clinical outcomes in VAP patients, but the increased rates clinical cure and microbiological eradication were not associated with reduced mortality. The use of nebulized antibiotics is not supported by the currently available evidence as a routine therapeutic strategy for VAP.

PROSPERO REGISTRATION NUMBER

CRD42020186970.

Pulmonary biofilm-based chronic infections and inhaled treatment strategies

Certain pulmonary diseases, such as cystic fibrosis (CF), non-CF bronchiectasis, chronic obstructive pulmonary disease, and ventilator-associated pneumonia, are usually accompanied by respiratory tract infections due to the physiological alteration of the lung immunological defenses. Recurrent infections may lead to chronic infection through the formation of biofilms. Chronic biofilm-based infections are challenging to treat using antimicrobial agents. Therefore, effective ways to eradicate biofilms and thus relieve respiratory tract infection require the development of efficacious agents for biofilm destruction, the design of delivery carriers with biofilm-targeting and/or penetrating abilities for these agents, and the direct delivery of them into the lung. This review provides an in-depth description of biofilm-based infections caused by pulmonary diseases and focuses on current existing agents that are administered by inhalation into the lung to treat biofilm, which include i) inhalable antimicrobial agents and their combinations, ii) non-antimicrobial adjuvants such as matrix-targeting enzymes, mannitol, glutathione, cyclosporin A, and iii) liposomal formulations of anti-biofilm agents. Finally, novel agents that have shown promise against pulmonary biofilms as well as traditional and new devices for pulmonary delivery of anti-biofilm agents into the lung are also discussed.

Anti-infectious decontamination strategies in Dutch intensive care units: A survey study on contemporary practice and heterogeneity

PURPOSE

Despite increasing evidence and updated national guidelines, practice of anti-infectious strategies appears to vary in the Netherlands. This study aimed to determine the variation of current practices of anti-infectious strategies in Dutch ICUs.

MATERIALS AND METHODS

In 2018 and 2019 an online survey of all Dutch ICUs was conducted with detailed questions on their anti-infectious strategies.

RESULTS

89% (63 of 71) of the Dutch ICUs responded to the online survey. The remaining ICUs were contacted by telephone. 47 (66%) of the Dutch ICUs used SDD, 14 (20%) used SOD and 10 (14%) used neither SDD nor SOD. Within these strategies considerable heterogeneity was observed in the start criteria of SDD/SOD, the regimen adjustments based on microbiological surveillance and the monitoring of the interventions.

CONCLUSIONS

The proportion of Dutch ICUs applying SDD or SOD increased over time. Considerable heterogeneity in the regimens was reported. The impact of the observed differences within SDD and SOD practices on clinical outcome remains to be explored.

Status of inhalable antimicrobial agents for lung infection: progress and prospects

Introduction: Available parenteral and oral administration of antimicrobial agents (AMAs) in respiratory infections often show less penetration into the lung parenchyma. Due to inappropriate dose availability, the rate of antibiotic resistance is increasing gradually. Inhaled antibiotics intensely improve the availability of drugs at the site of respiratory infections. This targeted delivery minimizes systemic exposure and associated toxicity.Area covers: This review was performed by searching in the scientific database like PubMed and several trusted government sites like fda.gov, cdc.gov, ClinicalTrials.gov, etc. For better understanding, AMAs are classified in different stages of approval. Mechanism and characterization of pulmonary drug deposition section helps to understand the effective delivery of AMAs to the respiratory tract. There is a need for proper adoption of delivery devices for inhalable AMAs. Thus, delivery devices are extensively explained. Inspiratory flow has a remarkable impact on the delivery device that has been explained in detail.Expert opinion: Pulmonary delivery restricts the bulk administration of drugs in comparison with other routes. Therefore, novel AMAs with higher bactericidal activity at lower concentrations need to be synthesized. Extensive research is indeed in developing innovative delivery devices that would able to deliver higher doses of AMAs through the pulmonary route.

Comparison of Inhaled Colistin with Inhaled Amikacin-Fosfomycin in the Treatment of Ventilator-Associated Pneumonia Caused by Extensively Drug-Resistant (XDR) Acinetobacter: A Clinical Trial

Background: This study aimed to compare the effects of inhaled colistin and inhaled amikacin-fosfomycin combination in the treatment of ventilator-associated pneumonia (VAP) caused by extensively drug-resistant (XDR) Acinetobacter. This clinical trial is the first study to evaluate the effect of inhaled fosfomycin on VAP in Iran. Methods: In this clinical trial, 60 patients with Acinetobacter VAP were divided into two groups of 30 patients. The empirical regimen changed to meropenem plus intravenous colistin in both groups. Inhaled colistin in the first group and inhaled amikacin-fosfomycin in the second group were added to the intravenous therapy. Next, the mortality rate, if any, duration of treatment success, and patient withdrawal from VAP were evaluated in the two groups. Results: Although the mean clinical pulmonary infection score (CPIS) before treatment was not significantly different between the two groups, the mean score of the amikacin-fosfomycin group was significantly lower at 72 hours and seven days after the onset of treatment and at the end of treatment. Based on the intra-group assessments, the CPIS in both groups was significantly reduced (P < 0.001). Also, in the inter-group assessments, the mean CPIS changes were significantly different between the two groups, and in the amikacin-fosfomycin group, a greater reduction in the CPIS was observed (P = 0.007). Conclusions: The findings of the present study showed that the use of amikacin-fosfomycin nebulization could lead to increased recovery and reduced treatment duration in patients with VAP, caused by drug-resistant Acinetobacter baumannii.

Issues in antibiotic therapy for hospital-acquired and ventilator-associated pneumonia: emerging concepts to improve outcomes

Introduction:Ventilator-associated pneumonia (VAP) and hospital-acquired pneumonia (HAP) result in significant morbidity and mortality. The emergence of multi-drug resistant organisms has complicated the matter, as many of these pathogens now represent key causes of VAP and HAP. While anumber of new medications have been approved, acomprehensive appreciation of pharmacokinetic and pharmacodynamic principles, which, are often neglected, is key to effective treatment.Areas covered: The authors discuss the central pharmacokinetic and pharmacodynamic principles underlying antibiotic utilization, especially as they pertain to the treatment of VAP and HAP. They further address the concept of and implications of augmented renal clearance for the patient with nosocomial pneumonia. Finally, the authors review the evolving data on colistin and inhaled antibiotics in the management of pneumonia.Expert opinion: An enhanced understanding of the pharmacokinetic and pharmacodynamic principles along with insight into the concept of augmented renal clearance can help guide drug development and improve the way we currently dose and deliver most antibiotics. There is now mounting data on the limited efficacy and substantial nephrotoxicity of colistin, which makes it difficult to justify its continued use. While the concept of inhaled antibiotics is enticing, we lack conclusive data proving the efficacy of this paradigm.