Antibiotic therapy for nonfermenting Gram-negative bacilli infections: future perspectives.

PURPOSE OF REVIEW: Serious infections caused by nonfermenting Gram-negative bacteria (NF-GNB) pose a significant challenge for clinicians due to the limited treatment options available, which are frequently associated with issues of toxicity and unfavourable pharmacokinetic profiles. The aim of this review is to provide a brief overview of the existing data concerning the ongoing development of antiinfective agents targeting NF-GNB. RECENT FINDINGS: Several agents exhibiting efficacy against NF-GNB are under clinical investigation. Durlobactam-sulbactam and cefepime-taniborbactam emerge as promising therapeutic avenues against carbapenem-resistant Acinetobacter baumanii . Cefepime-zidebactam may serve as a suitable treatment option for urinary tract infections caused by a wide range of NF-GNB. Cefepime-enmetazobactam demonstrates potent in vitro activity against various NF-GNB strains; however, its role as an anti- Pseudomonal agent is inadequately substantiated by available data. Xeruborbactam is a wide ß-lactamase inhibitor that can be associated with a range of agents, enhancing in-vitro activity of these against many NF-GNB, including those resistant to newer, broader spectrum options. Lastly, murepavadin appears to be a potential pathogen-specific solution for severe Pseudomonas infections; however, additional investigation is necessary to establish the safety profile of this compound. SUMMARY: Each of the novel molecules reviewed possesses an interesting range of in-vitro activity against NF-GNB. In addition, some of them have already been proved effective in vivo, underscoring their potential as future treatment options.

Therapeutic options for difficult-to-treat Acinetobacter baumannii infections: a 2020 perspective.

INTRODUCTION: Treatment of severe infections due to Acinetobacter baumannii with difficult-to-treat resistance (DTR-AB), which exhibits resistance to all ß-lactams, ß-lactam/ß-lactamases inhibitor combinations, and fluoroquinolones, remains a challenge for clinicians. AREAS COVERED: The present perspective provides a personal view on both current and future agents for the treatment of severe DTR-AB infections. EXPERT OPINION: We currently are in a transition era for the treatment of DTR-AB infections, where in the past 20 years, polymyxin-based regimens have become the most used approach (although possibly suboptimal, there were few or no alternatives) and where in the next 20 years, polymyxins will likely be replaced by less toxic novel agents as first-line choices. Two novel antimicrobial agents have been recently approved that show activity against DTR-AB, cefiderocol and eravacycline, while durlobactam/sulbactam is in phase-3 of clinical development. In the near future, these agents could become important first-line choices for the treatment of DTR-AB within approved indications, or for off-label indications in the absence of dependable alternatives. Good-quality post-marketing experiences remain necessary for arising clinically relevant questions and guiding the design of further dedicated randomized controlled trials to stably optimize the use of novel agents for DTR-AB infections in the next decades.

The role of new antimicrobials for Gram-negative infections in daily clinical practice.

PURPOSE OF REVIEW: To discuss a possible clinical reasoning for treating resistant Gram-negative bacteria (GNB) infections in daily clinical practice, as well as developing a research agenda for the field. RECENT FINDINGS: Novel agents, both belonging to ß-lactams and to other classes of antimicrobials, have recently become available, likely replacing polymyxins or polymyxin-based combination regimens as the preferred choices for the first-line treatment of severe resistant GNB infections in the near future. SUMMARY: The peculiar characteristics of novel agents for severe resistant GNB infections have abruptly made the structure of previous therapeutic algorithms somewhat obsolete, in view of the differential activity of most of them against different classes of carbapenemases. Furthermore, other agents showing activity against resistant GNB are in late phase of clinical development. Optimizing the use of novel agents in order both to guarantee the best available treatment to patients and to delay the emergence and spread of resistance is an important task that cannot be postponed, especially considering the unavailability of well tolerated and fully efficacious options for treating resistant GNB infections that we faced in the last 15 years.

Treatment of extended-spectrum ß-lactamases infections: what is the current role of new ß-lactams/ß-lactamase inhibitors?

PURPOSE OF REVIEW: The widespread diffusion of extended-spectrum ß-lactamases (ESBLs)-producing Enterobacteriales currently represents a major threat for public health worldwide. Carbapenems are currently considered the first-line choice for serious ESBL infections. However, the dramatic global increase in ESBL prevalence has led to a significant overuse of carbapenems that has promoted the selection and spread of carbapenemases, which might further prejudicated our ability to treat infections due to multidrug-resistant pathogens. Therefore, strategies to limit the use of carbapenems should be implemented. RECENT FINDINGS: Although piperacillin-tazobactam should no longer be considered an alternative to carbapenems for definitive treatment of bloodstream infections due to ESBL-producing strains, it might still represent an alternative for step-down therapy or for low-to-moderate severity infection originating from urinary or biliary sources and when piperacillin-tazobactam minimum inhibitory concentration of 4 mg/l or less. Ceftazidime-avibactam and ceftolozane-tazobactam are both carbapenem sparing agents that appear interesting alternatives for treatment of serious ESBL infections. New ß-lactams/ß-lactamase inhibitors (BL/BLI), including cefepime-enmetazobactam, ceftaroline fosamil-avibactam, aztreonam-avibactam and cefepime-zidebactam, are also promising agents for treatment of ESBL infections, but further clinical data are needed to establish their efficacy relative to carbapenems. The role of carbapenems/ß-lactamase inhibitors remain to be clarified. SUMMARY: New BL/BLI have distinctive specificities and limitations that require further investigations. Future randomized clinical trials are required to define the best strategy for their administering for ESBL infections.

Ceftaroline for severe community-acquired pneumonia: A real-world two-centre experience in Italy and Spain.

BACKGROUND: Ceftaroline is one of latest additions to the armamentarium for treating community-acquired pneumonia (CAP). This study aimed to describe the outcome of severe CAP (SCAP) in a cohort of hospitalised patients treated with ceftaroline. METHODS: A retrospective, observational study of patients with SCAP treated with ceftaroline in two hospitals in Spain and Italy. The primary objective was to explore 30-day mortality after diagnosis of SCAP. RESULTS: During the study period the following were observed: there were 89 cases of SCAP treated with ceftaroline and 53 cases used in combination with other antibiotics (60%). Overall, 30-day mortality and clinical failure were 20% (18 of 89) and 36% (32 of 89), respectively. Independent predictors of 30-day mortality were: increasing age (OR for 1 year increase 1.0, 95% CI 1.0-1.1, P 0.043), presence of solid neoplasm (OR 4.0, 95% CI 1.0-15.1, P 0.044) and concomitant therapy with oseltamivir (OR 8.5, 95% CI 1.2°57.3, P 0.029). The only independent predictor of clinical failure was the time elapsing from SCAP diagnosis to ceftaroline therapy (OR for each passing day 1.5, 95% CI 1.1-1.9, P 0.003). The clinical success rate was 64% (57 of 89). In the subgroups of patients with proven Streptococcus pneumoniae, methicillin-susceptible Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) infection, clinical success was 83% (10 of 12), 75% (three of four) and 56% (five of nine), respectively. CONCLUSIONS: Considering its spectrum of activity, ceftaroline could represent an important therapeutic option for SCAP. Further studies are needed to identify the precise clinical success rate against MRSA in a larger cohort of patients with SCAP.

Dalbavancin in the treatment of different gram-positive infections: a real-life experience.

Dalbavancin is a lipoglycopeptide with a very prolonged half-life enabling treatment with a single intravenous administration that has been approved to treat complicated skin and soft-tissue infections. Information on the efficacy and safety of dalbavancin in other situations is very scarce. This retrospective study included adult patients who received at least one dose of dalbavancin between 2016 and 2017 in 29 institutions in Spain. The primary objective was to report the use of dalbavancin in clinical practice, including its efficacy and tolerability. The potential impact of dalbavancin on reducing the length of hospital stay and hospital costs was also evaluated. A total of 69 patients received dalbavancin during the study period (58.0% male; median age 63.5 years). Dalbavancin was used to treat prosthetic joint infection (29.0%), acute bacterial skin and skin-structure infection (21.7%), osteomyelitis (17.4%) and catheter-related bacteraemia (11.6%). These infections were mainly caused by Staphylococcus aureus (27 isolates), coagulase-negative staphylococci (24 isolates) and Enterococcus spp. (11 isolates). All but two patients received previous antibiotics for a median of 18 days. Dalbavancin was administered for a median of 21 days (range 7-168 days), and concomitant antimicrobial therapy was prescribed to 25 patients (36.2%). The overall clinical success rate of dalbavancin was 84.1%. Adverse events, mainly mild in intensity, were reported in nine patients. Overall, dalbavancin was estimated to reduce hospitalisation by 1160 days, with an estimated overall cost reduction of €211 481 (€3064 per patient). Dalbavancin appears to be an effective therapy for many serious Gram-positive infections.

Echinocandins Compared to Fluconazole for Candidemia of a Urinary Tract Source: A Propensity Score Analysis.

BACKGROUND: Whether echinocandins could be used to treat candidemia of a urinary tract source (CUTS) is unknown. We aimed to provide current epidemiological information of CUTS and to compare echinocandin to fluconazole treatment on CUTS outcomes. METHODS: A multicenter study of adult patients with candidemia was conducted in 9 hospitals. CUTS was defined as a candidemia with concomitant candiduria by the same organism associated with significant urological comorbidity. The primary outcome assessed was clinical failure (defined by 7-day mortality or persistent candidemia) in patients treated with either an echinocandin or fluconazole. A propensity score was calculated and then entered into a regression model. RESULTS: Of 2176 episodes of candidemia, 128 were CUTS (5.88%). Most CUTS cases were caused by Candida albicans (52.7%), followed by Candida glabrata (25.6%) and Candida tropicalis (16.3%). Clinical failure occurred in 7 patients (20%) treated with an echinocandin and in 15 (17.1%) treated with fluconazole (P = .730). Acute renal failure (adjusted odds ratio [AOR], 3.01; 95% confidence interval [CI], 1.01-8.91; P = .047) was the only independent factor associated with clinical failure, whereas early urinary tract drainage procedures (surgical, percutaneous, or endoscopic) were identified as protective (AOR, 0.08; 95% CI, .02-.31; P < .001). Neither univariate nor multivariate analysis showed that echinocandin therapy altered the risk of clinical failure. CONCLUSIONS: Initial echinocandin therapy was not associated with clinical failure in patients with CUTS. Notably, acute renal failure predicted worse outcomes and performing an early urologic procedure was a protective measure.

Daptomycin plus trimethoprim/sulfamethoxazole combination therapy in post-neurosurgical meningitis caused by linezolid-resistant Staphylococcus epidermidis.

Post-neurosurgical infection is a serious complication that occurs in approx. 4% of all patients undergoing neurosurgical procedures and is associated with high morbidity and mortality rates and prolonged length of intensive care unit (ICU) stay. Coagulase-negative staphylococci (CoNS), especially methicillin-resistant Staphylococcus epidermidis (MRSE), are the most frequent pathogens involved in CNS post-neurosurgical meningitis. Treatment is challenging especially in patients with meningitis due to multidrug- resistant (MDR) CONS. Herein, we report a unique case of post-neurosurgical meningitis due to MRSE resistant to linezolid (a molecular analysis revealed the presence of the mutation G2576T on domain V of the 23S rRNA gene) and with reduced susceptibility to glycopeptides, successfully treated with a combination of daptomycin at 10 mg/kg daily plus trimethoprim/sulfamethoxazole (TMP/SMX). This antibiotic combination showed an indifferent interaction in in vitro studies. Daptomycin serum and cerebrospinal fluid (CSF) concentrations, determined through blood and CSF samples drawn just prior to and 4 h after the third dose, were 18.9-0.78 and 51.65-3.1 mg/L, respectively. These values allowed us to approximate a 5-6% penetration rate of the drug through an inflamed blood-brain barrier. In conclusion, although further studies are needed, combination of high-dose daptomycin plus TMP/SMX is a reasonable option for treatment of meningitis caused by multidrug-resistant S. epidermidis.