Ceftazidime/Avibactam in Ventilator-Associated Pneumonia Due to Difficult-to-Treat Non-Fermenter Gram-Negative Bacteria in COVID-19 Patients: A Case Series and Review of the Literature

Stenotrophomonas maltophilia: The Landscape in Critically Ill Patients and Optimising Management Approaches

The aim of this review is to synthesise the key aspects of the epidemiology, current microbiological diagnostic challenges, antibiotic resistance rates, optimal antimicrobial management, and most effective prevention strategies for Stenotrophomonas maltophilia (SM) in the intensive care unit (ICU) population. In recent years, resistance surveillance data indicate that SM accounts for less than 3% of all healthcare-associated infection strains, a percentage that doubles in the case of ventilator-associated pneumonia (VAP). Interestingly, SM ranks as the third most isolated non-glucose fermenter Gram-negative bacilli (NFGNB). Although this NFGNB genus has usually been considered a bystander and colonising strain, recently published data warn about its potential role as a causative pathogen of severe infections, particularly pneumonia and bloodstream infections (BSI), not only for the classical immunocompromised susceptible host patients but also for critically ill ones even without overt immunosuppression. Indeed, it has been associated with crude 28-day mortality as high as 54.8%, despite initial response following targeted therapy. Additionally, alongside its intrinsic resistance to a wide range of common antimicrobials, various worldwide and local surveillance studies raise concerns about an increase in ICU settings regarding resistance to first-line drugs such as cotrimoxazole or tigecycline. This scenario alerts ICU physicians to the need to reconsider the best stewardship approach when SM is isolated in obtained samples from critically ill patients. Despite the coverage of this multidrug-resistant bacterium (MDRB) provided by some traditional and a non-negligible number of current pipeline antimicrobials, an ecological and cost-effective strategy is needed in the present era.

Novel Siderophore Cephalosporin and Combinations of Cephalosporins with β-Lactamase Inhibitors as an Advancement in Treatment of Ventilator-Associated Pneumonia

In an era of increasing antibiotic resistance among pathogens, the treatment options for infectious diseases are diminishing. One of the clinical groups especially vulnerable to this threat are patients who are hospitalized in intensive care units due to ventilator-associated pneumonia caused by multidrug-resistant/extensively drug-resistant Gram-negative bacteria. In order to prevent the exhaustion of therapeutic options for this life-threatening condition, there is an urgent need for new pharmaceuticals. Novel β-lactam antibiotics, including combinations of cephalosporins with β-lactamase inhibitors, are proposed as a solution to this escalating problem. The unique mechanism of action, distinctive to this new group of siderophore cephalosporins, can overcome multidrug resistance, which is raising high expectations. In this review, we present the summarized results of clinical trials, in vitro studies, and case studies on the therapeutic efficacy of cefoperazone-sulbactam, ceftolozane-tazobactam, ceftazidime-avibactam, and cefiderocol in the treatment of ventilator-associated pneumonia. We demonstrate that treatment strategies based on siderophore cephalosporins and combinations of β-lactams with β-lactamases inhibitors show comparable or higher clinical efficacy than those used with classic pharmaceuticals, like carbapenems, colistin, or tigecycline, and are often associated with a lower risk of adverse events.

Global mapping of antibiotic resistance rates among clinical isolates of Stenotrophomonas maltophilia: a systematic review and meta-analysis

INTRODUCTION

Infections caused by Stenotrophomonas maltophilia are clinically important due to its intrinsic resistance to a broad range of antibiotics. Therefore, selecting the most appropriate antibiotic to treat S. maltophilia infection is a major challenge.

AIM

The current meta-analysis aimed to investigate the global prevalence of antibiotic resistance among S. maltophilia isolates to the develop more effective therapeutic strategies.

METHOD

A systematic literature search was performed using the appropriate search syntax after searching Pubmed, Embase, Web of Science and Scopus databases (May 2023). Statistical analysis was performed using Pooled and the random effects model in R and the metafor package. A total of 11,438 articles were retrieved. After a thorough evaluation, 289 studies were finally eligible for inclusion in this systematic review and meta-analysis.

RESULT

Present analysis indicated that the highest incidences of resistance were associated with doripenem (97%), cefoxitin (96%), imipenem and cefuroxime (95%), ampicillin (94%), ceftriaxone (92%), aztreonam (91%) and meropenem (90%) which resistance to Carbapenems is intrinsic. The lowest resistance rates were documented for minocycline (3%), cefiderocol (4%). The global resistance rate to TMP-SMX remained constant in two periods before and after 2010 (14.4% vs. 14.6%). A significant increase in resistance to tigecycline and ceftolozane/tazobactam was observed before and after 2010.

CONCLUSIONS

Minocycline and cefiderocol can be considered the preferred treatment options due to low resistance rates, although regional differences in resistance rates to other antibiotics should be considered. The low global prevalence of resistance to TMP-SMX as a first-line treatment for S. maltophilia suggests that it remains an effective treatment option.

Trends and patterns of antibiotics use in Serbia from 2006 to 2021: Pre-COVID-19 period versus COVID-19 pandemic

BACKGROUND

Global rise in antibiotic utilization has been strongly associated with the resistance of bacteria to antibiotics. The COVID-19 saw an increase in the use of antibiotics in some countries. The aim of this study was to evaluate antibiotic utilization from 2006 to 2021 in the Republic of Serbia.

METHODS

Data on antibiotic use were retrieved from the national annual reports on the official website of the Medicines and Medical Devices Agency of Serbia during the period 2006 to 2021. To evaluate trends in the use of antibiotics in Serbia, linear, and joint regression analyses were performed.

RESULTS

The analysis of the antibiotics use over a sixteen-year period included a total of 50 antibiotics. A significant increase during the COVID-19 pandemic was observed for glycylcyclines that is, new-generation tetracyclines (tigecycline), third-generation cephalosporins (ceftazidime, ceftriaxone, and cefixime), respiratory fluoroquinolones (levofloxacin and moxifloxacin), carbapenems (ertapenem), and oxazolidinones (linezolid) utilization. Moreover, an almost negligible use of new β-lactam/β-lactamase inhibitors during the prepandemic period increased significantly during the COVID-19 pandemic period.

CONCLUSIONS

A significant increasing trend in the use of specific antibiotics classified as the "Watch" and "Reserve" antibiotics during the pandemic period was observed.

Intravenous Fosfomycin for Systemic Multidrug-Resistant Pseudomonas aeruginosa Infections

Human Pseudomonas infections have high morbidity and mortality rates. Pseudomonas bacteria can cause sepsis or septic shock; they produce biofilm and commonly exhibit a multidrug-resistant phenotype. The choice of antimicrobial therapy in many cases is challenging, and deep knowledge of clinical, microbiological, and pharmacological issues is required. Intravenous fosfomycin is being repurposed in a combination given its favorable pharmacokinetic/pharmacodynamic properties (a small molecule with favorable kinetic both in bloodstream infection and in deep-seated infections), antibiofilm activity, and its interesting synergistic effects with other antimicrobials. Recent literature on epidemiological, microbiological, pharmacological, and clinical data on intravenous fosfomycin therapy against Pseudomonas is herein reviewed and discussed.

Antibiotic-Resistant ESKAPE Pathogens and COVID-19: The Pandemic beyond the Pandemic

Antibacterial resistance is a renewed public health plague in modern times, and the COVID-19 pandemic has rekindled this problem. Changes in antibiotic prescribing behavior, misinformation, financial hardship, environmental impact, and governance gaps have generally enhanced the misuse and improper access to antibiotics during the COVID-19 pandemic. These determinants, intersected with antibacterial resistance in the current pandemic, may amplify the potential for a future antibacterial resistance pandemic. The occurrence of infections with multidrug-resistant (MDR), extensively drug-resistant (XDR), difficult-to-treat drug-resistant (DTR), carbapenem-resistant (CR), and pan-drug-resistant (PDR) bacteria is still increasing. The aim of this review is to highlight the state of the art of antibacterial resistance worldwide, focusing on the most important pathogens, namely Enterobacterales, Acinetobacter baumannii, and Klebsiella pneumoniae, and their resistance to the most common antibiotics.

An overview of gram-negative bacteria with difficult-to-treat resistance: definition, prevalence, and treatment options

INTRODUCTION

Difficult-to-treat resistance (DTR) is a newly proposed resistance phenotype characterized by resistance to all first-line drugs. The emergence of DTR as a new resistance phenotype has significant implications for clinical practice. This new concept has the potential to be widely used instead of traditional phenotypes.

AREAS COVERED

This study carried out a detailed analysis about the definition, application, and evolution of various resistance phenotypes. We collected all the research articles on Gram-negative bacteria with difficult-to-treat resistance (GNB-DTR), analyzed the DTR in each region and each bacterial species. The advantages and doubts of DTR, the dilemma of GNB-DTR infections and the potential therapeutic strategies are summarized in the review.

EXPERT OPINION

Available studies show that the prevalence of GNB-DTR is not optimistic. Unlike traditional resistance phenotypes, DTR is more closely aligned with the clinical treatment perspective and can help with the prompt selection of an appropriate treatment plan. Currently, potential treatment options for GNB-DTR include a number of second-line drugs and novel antibiotics. However, the definition of first-line drugs is inherently dynamic. Therefore, the DTR concept based on first-line drugs needs to be continuously updated and refined, considering the emergence of new antibiotics, resistance characteristics, and pathogen prevalence in different regions.

The Use of Intravenous Fosfomycin in Clinical Practice: A 5-Year Retrospective Study in a Tertiary Hospital in Italy

Fosfomycin in intravenous (IV) formulation has re-emerged as a valuable tool in the treatment of multi-drug resistant (MDR) and extensively drug-resistant (XDR) infections because of its broad spectrum of antibacterial action and pharmacokinetic characteristics. This retrospective study aimed to evaluate how fosfomycin was used in patients admitted to the Polyclinic of Palermo between January 2017 and July 2022. Clinical indications, therapeutic associations, clinical outcomes, and any side effects were analyzed. Intravenous fosfomycin was used in 343 patients, 63% male, with a mean age of 68 years (range 15-95). Urinary tract infections (UTIs) and hospital-acquired pneumonia (HAP) were the main indications for treatment (19% and 18% of the total cases, respectively), followed by skin and soft tissue infections and sepsis. IV fosfomycin was administered in combination with other antibacterial agents, the most common of which were ceftazidime/avibactam (35%), meropenem (17%), and colistin (14%). Nineteen patients received it as monotherapy for UTIs. About 66% had resolution of the infectious process with clinical remission (cure or discharge). Electrolyte disturbances occurred in 2.6% and gastrointestinal symptoms occurred in 2.9%. The data showed that IV fosfomycin is a safe and effective therapeutic option in the treatment of infections with multidrug-resistant microorganisms.

Real-Life Assessment of the Ability of an Ultraviolet C Lamp (SanificaAria 200, Beghelli) to Inactivate Airborne Microorganisms in a Healthcare Environment

Airborne-mediated microbial diseases represent one of the major challenges to public health. Ultraviolet C radiation (UVC) is among the different sanitation techniques useful to reduce the risk of infection in healthcare facilities. Previous studies about the germicidal activity of UVC were mainly performed in artificial settings or in vitro models. This study aimed to assess the sanitizing effectiveness of a UVC device (SanificaAria 200, Beghelli, Valsamoggia, Bologna, Italy) in 'real-life' conditions by evaluating its ability to reduce microbial loads in several hospital settings during routine daily activities. The efficacy of the UVC lamp in reducing the bacterial component was evaluated by microbial culture through the collection of air samples in different healthcare settings at different times (30 min-24 h) after turning on the device. To assess the anti-viral activity, air samplings were carried out in a room where a SARS-CoV-2-positive subject was present. The UVC device showed good antibacterial properties against a wide range of microbial species after 6 h of activity. It was effective against possible multi-drug resistant microorganisms (e.g., Pseudomonas spp., Acinetobacter spp.) and spore-forming bacteria (e.g., Bacillus spp.). In addition, the UVC lamp was able to inactivate SARS-CoV-2 in just one hour. Thanks to its effectiveness and safety, SanificaAria 200 could be useful to inactivate airborne pathogens and reduce health risks.

Bacterial pneumonia associated with multidrug-resistant Gram-negative pathogens: Understanding epidemiology, resistance patterns, and implications with COVID-19

The ongoing spread of antimicrobial resistance has complicated the treatment of bacterial hospital-acquired pneumonia (HAP) and ventilator-associated pneumonia (VAP). Gram-negative pathogens, especially those with multidrug-resistant profiles, including Escherichia coli, Klebsiella pneumoniae, Enterobacter spp., Pseudomonas aeruginosa, and Acinetobacter spp., are an important culprit in this type of infections. Understanding the determinants of resistance in pathogens causing pneumonia is ultimately stressing, especially in the shadows of the COVID-19 pandemic, when bacterial lung infections are considered a top priority that has become urgent to revise. Globally, the increasing prevalence of these pathogens in respiratory samples represents a significant infection challenge, with major limitations of treatment options and poor clinical outcomes. This review will focus on the epidemiology of HAP and VAP and will present the roles and the antimicrobial resistance patterns of implicated multidrug-resistant (MDR) Gram-negative pathogens like carbapenem-resistant Acinetobacter baumannii (CRAB), carbapenem-resistant Pseudomonas aeruginosa (CRPA), carbapenem-resistant Enterobacterales (CRE), as well as colistin-resistant Gram-negative pathogens and extended-spectrum β-lactamase (ESBL)-producing Enterobacterales. While emerging from the COVID-19 pandemic, perspectives and conclusions are drawn from findings of HAP and VAP caused by MDR Gram-negative bacteria in patients with COVID-19.

Population Pharmacokinetic Modeling for Ceftazidime-Avibactam Renal Dose Adjustments in Pediatric Patients 3 months and Older

Ceftazidime-avibactam is a novel β-lactam/β-lactamase inhibitor combination developed to treat serious Gram-negative bacterial infections; approved indications include complicated urinary tract infection, complicated intra-abdominal infection, and hospital-acquired pneumonia including ventilator-associated pneumonia in patients ≥ 3 months old. Because of the predominantly renal clearance of ceftazidime and avibactam, dose adjustments (reductions) are required for patients with estimated creatinine clearance (CrCL) ≤ 50 mL/min. We describe the application of combined adult and pediatric population pharmacokinetic models in developing ceftazidime-avibactam dose recommendations for pediatric patients ≥ 2 to < 18 years old with body surface area-normalized CrCL ≤ 50 mL/min/1.73 m² , including moderate, severe, or very severe renal impairment, or end-stage renal disease requiring hemodialysis, and for patients ≥ 3 months to < 2 years old with mild, moderate, or severe renal impairment. Models included allometric scaling for all subjects and simulations (1,000 subjects per age group, renal function group, and indication) were performed nonparametrically using post hoc random effects. Doses were selected based on simulated pediatric patients achieving steady-state exposures similar to adults and high probability of target attainment (using a simultaneous joint target for both ceftazidime and avibactam). Because there were few children with renal impairment in the ceftazidime-avibactam clinical trials, selected pediatric doses were guided by extrapolation and matching of adult exposures associated with efficacy and within established safety margins. The recommended doses for pediatric patients with estimated CrCL ≤ 50 mL/min/1.73 m² use equivalent adjustments in dose quantity and/or administration interval (vs. the corresponding age group with normal renal function) as those for adults.