Epidemiology and regional variation of nonsusceptible and multidrug-resistant Pseudomonas aeruginosa isolates from intensive versus non-intensive care units across multiple centers in the United States

A real-world investigation into prescribing patterns and effectiveness of ceftolozane/tazobactam among critically ill patients from SPECTRA

BACKGROUND

Ceftolozane/tazobactam (C/T) real-world use was examined in a global population of critical care patients treated in intensive care unit settings.

METHODS

The Study of Prescribing patterns and Effectiveness of Ceftolozane/Tazobactam Real-world Analysis (SPECTRA) is a multinational, retrospective observational study of 617 adults treated with C/T conducted between 2016 and 2020. Population-associated clinical, treatment-related, and microbiologic characteristics, resource utilization, and clinical outcomes were assessed in critical care patients.

RESULTS

In this SPECTRA critical care cohort (n=298), 81.5% had ≥1 comorbidity. Common infection sites were respiratory (50.0%), skin/wound/tissue (21.1%), blood (13.7%), and urine (10.3%); common pathogens were Pseudomonas aeruginosa (89.7%; 66.7% multidrug resistant), Klebsiella spp. (6.9%), and Escherichia coli (6.4%); 51.7% received C/T as third-line/salvage therapy. Thirty-day readmission rates were 3.4% (all cause) and 1.7% (infection related). Overall clinical success was 53.4% (95% confidence interval: 47.5% to 59.1%) and was greater with first-line C/T (62.2%) versus third line (45.5%). All-cause in-hospital mortality was 35.6%; infection-related mortality was 13.8%.

CONCLUSIONS

In this multinational, high-risk cohort, most patients had beneficial outcomes despite their clinical complexity and late intervention with C/T. These results support C/T use against a wide range of Gram-negative pathogens in critical care settings.

TRIAL REGISTRATION

Not applicable due to retrospective design.

Unveiling results and insights from multinational, multicenter Study of Prescribing patterns and Effectiveness of Ceftolozane/Tazobactam Real-world Analysis (SPECTRA)

OBJECTIVES

Antibacterial-resistant gram-negative hospital-acquired infections result in significant morbidity and mortality. In clinical trials, ceftolozane/tazobactam (C/T) has been effective against these infections; however, real-world findings are limited.

METHODS

SPECTRA was a global, retrospective, observational inpatient study of adults treated with C/T for ≥48 h, conducted between 2016 and 2020. The primary objective was to describe real-world utilisation of C/T: socio-demographic, clinical characteristics, prescribing patterns, clinical outcomes, and healthcare resource utilisation in hospitalised patients treated with C/T.

RESULTS

In total, 617 patients from 7 countries met inclusion criteria. Most (82.7%) had ≥1 comorbidity. The most common medical conditions where C/T was used were pneumonia (29.5%), sepsis (20.4%), complicated intra-abdominal infection (15.1%), and complicated urinary tract infection (14.4%). The most common pathogens were Pseudomonas aeruginosa (87.4%) and Escherichia coli (8.2%). Median C/T treatment duration was 11 days. Clinical success occurred in 67.3% of patients (including those with 'unknown' status in the denominator). In a separate analysis that excluded those with 'unknown' status, clinical success ranged from 94.1% in patients with bacteraemia to 58.9% with sepsis. Overall, 18.8% of patients had documented microbiologic response. All-cause in-hospital mortality was 21.2%; infection-related mortality was 7.6%. Median hospital length of stay was 42 days (30 days for those who received early C/T therapy [before pathogen identification] vs. 48 days for definitive therapy [after identification]).

CONCLUSIONS

These data elucidate real-world utilisation and prescribing patterns of C/T in a diverse patient population with complex medical conditions and various profiles of pathogen resistance between 2016 and 2020.

Real-world evaluation of imipenem/cilastatin/relebactam across US medical centres

We assessed 160 patients who received imipenem/cilastatin/relebactam for ≥2 days. At treatment initiation, the median Charlson Comorbidity Index was 5, 45% were in the intensive care unit, and 19% required vasopressor support. The in-hospital mortality rate was 24%. These data advance our understanding of real-world indications and outcomes of imipenem/cilastatin/relebactam use.

Perspectives on the use of ceftolozane/tazobactam: a review of clinical trial data and real-world evidence

Hospital-acquired bacterial pneumonia (HABP) and ventilator-associated bacterial pneumonia (VABP) are common healthcare-associated infections linked to high morbidity and mortality. Gram-negative pathogens, such as Pseudomonas aeruginosa, exhibit multidrug resistance and are recognized as major public health concerns, particularly among critically ill patients with HABP/VABP. Ceftolozane/tazobactam is a novel combination antibacterial agent comprising ceftolozane (a potent antipseudomonal cephalosporin) and tazobactam (a β-lactamase inhibitor). Phase III trials have demonstrated non-inferiority of ceftolozane/tazobactam to comparators, leading to the approval of ceftolozane/tazobactam for the treatment of complicated urinary tract infections, complicated intra-abdominal infections, and nosocomial pneumonia. In this article, we review the clinical trial evidence and key real-world effectiveness data of ceftolozane/tazobactam for the treatment of serious healthcare-associated Gram-negative infections, focusing on patients with HABP/VABP.

Participant- and Disease-Related Factors as Independent Predictors of Treatment Outcomes in the RESTORE-IMI 2 Clinical Trial: A Multivariable Regression Analysis

Background

In the RESTORE-IMI 2 trial, imipenem/cilastatin/relebactam (IMI/REL) was noninferior to piperacillin/tazobactam in treating hospital-acquired bacterial pneumonia/ventilator-associated bacterial pneumonia. This post hoc analysis was conducted to determine independent predictors of efficacy outcomes in the RESTORE-IMI 2 trial, to assist in treatment decision making.

Methods

A stepwise multivariable regression analysis was conducted to identify variables that were independently associated with day 28 all-cause mortality (ACM), favorable clinical response at early follow-up (EFU), and favorable microbiologic response at end of treatment (EOT). The analysis accounted for the number of baseline infecting pathogens and in vitro susceptibility to randomized treatment.

Results

Vasopressor use, renal impairment, bacteremia at baseline, and Acute Physiologic Assessment and Chronic Health Evaluation (APACHE) II scores ≥15 were associated with a greater risk of day 28 ACM. A favorable clinical response at EFU was associated with normal renal function, an APACHE II score <15, no vasopressor use, and no bacteremia at baseline. At EOT, a favorable microbiologic response was associated with IMI/REL treatment, normal renal function, no vasopressor use, nonventilated pneumonia at baseline, intensive care unit admission at randomization, monomicrobial infections at baseline, and absence of Acinetobacter calcoaceticus-baumannii complex at baseline. These factors remained significant after accounting for polymicrobial infection and in vitro susceptibility to assigned treatment.

Conclusions

This analysis, which accounted for baseline pathogen susceptibility, validated well-recognized patient- and disease-related factors as independent predictors of clinical outcomes. These results lend further support to the noninferiority of IMI/REL to piperacillin/tazobactam and suggests that pathogen eradication may be more likely with IMI/REL.

Clinical Trials Registration

NCT02493764.

Microevolution of Pseudomonas aeruginosa in the airways of people with cystic fibrosis

The chronic infections of cystic fibrosis (CF) airways with Pseudomonas aeruginosa are a paradigm of how environmental bacteria can conquer, adapt, and persist in an atypical habitat and successfully evade defense mechanisms and chemotherapy in a susceptible host. The within-host evolution of intraclonal diversity has been examined by whole-genome sequencing, phenotyping, and competitive fitness experiments of serial P. aeruginosa isolates collected from CF airways since onset of colonization for a period of up to 40 years. The spectrum of de novo mutations and the adaptation of phenotype and fitness of the bacterial progeny were more influenced by the living conditions in the CF lung than by the clone type of their ancestor and its genetic repertoire.