Risk factors for and clinical outcomes of carbapenem non-susceptible gram negative bacilli bacteremia in patients with acute myelogenous leukemia

Clinical outcomes of antimicrobial resistance in cancer patients: a systematic review of multivariable models

BACKGROUND

Infections are major causes of disease in cancer patients and pose a major obstacle to the success of cancer care. The global rise of antimicrobial resistance threatens to make these obstacles even greater and hinder continuing progress in cancer care. To prevent and handle such infections, better models of clinical outcomes building on current knowledge are needed. This internally funded systematic review (PROSPERO registration: CRD42021282769) aimed to review multivariable models of resistant infections/colonisations and corresponding mortality, what risk factors have been investigated, and with what methodological approaches.

METHODS

We employed two broad searches of antimicrobial resistance in cancer patients, using terms associated with antimicrobial resistance, in MEDLINE and Embase through Ovid, in addition to Cinahl through EBSCOhost and Web of Science Core Collection. Primary, observational studies in English from January 2015 to November 2021 on human cancer patients that explicitly modelled infection/colonisation or mortality associated with antimicrobial resistance in a multivariable model were included. We extracted data on the study populations and their malignancies, risk factors, microbial aetiology, and methods for variable selection, and assessed the risk of bias using the NHLBI Study Quality Assessment Tools.

RESULTS

Two searches yielded a total of 27,151 unique records, of which 144 studies were included after screening and reading. Of the outcomes studied, mortality was the most common (68/144, 47%). Forty-five per cent (65/144) of the studies focused on haemato-oncological patients, and 27% (39/144) studied several bacteria or fungi. Studies included a median of 200 patients and 46 events. One-hundred-and-three (72%) studies used a p-value-based variable selection. Studies included a median of seven variables in the final (and largest) model, which yielded a median of 7 events per variable. An in-depth example of vancomycin-resistant enterococci was reported.

CONCLUSIONS

We found the current research to be heterogeneous in the approaches to studying this topic. Methodological choices resulting in very diverse models made it difficult or even impossible to draw statistical inferences and summarise what risk factors were of clinical relevance. The development and adherence to more standardised protocols that build on existing literature are urgent.

Effectiveness of antimicrobial stewardship programmes based on rapid antibiotic susceptibility testing of haematologic patients having high-risk factors for bacteraemia related mortality: A post-hoc analysis of an RCT

OBJECTIVES

A randomised controlled trial showed that rapid phenotypic antibiotic susceptibility testing (AST) with antimicrobial stewardship programmes (ASP) increases the proportion of haematologic patients with bacteraemia receiving optimal targeted therapy within 72 hrs of blood culture collection. The present post-hoc analysis aimed to evaluate the effects of rapid phenotypic AST intervention in haematologic patients at high risk of a poor outcome from bacteraemia.

METHODS

Haematologic patients with bacteraemia (n = 116) were assigned randomly to a conventional AST group or a rapid AST group. The two outcome measures were the proportion of patients receiving optimal targeted therapy at 72 hrs post-blood culture collection and the time to optimal targeted therapy; subgroup analysis was conducted based on baseline demographics (age, sex) and prognostic (Charlson comorbidity index, haematologic treatment intensity, Pitt bacteraemia score, appropriateness of empirical antibiotic therapy and multidrug-resistant organism) indicators. The interaction effect between the intervention and subgroup factors was examined using regression model analysis.

RESULTS

Age, sex, Charlson comorbidity index, haematologic treatment intensity, Pitt bacteraemia score and appropriateness of empirical antibiotic therapy had no significant interaction effects on the proportion of patients receiving optimal targeted therapy (P = 0.129-0.826). However, infection by a multidrug-resistant organism did have a significant interaction effect (P = 0.042). Regarding time to optimal targeted therapy, there were no significant interaction effects between the intervention and subgroup factors (P = 0.156-0.848).

CONCLUSIONS

Rapid phenotypic AST intervention may accelerate early optimal targeted antimicrobial treatment of haematologic patients, even those in high-risk subgroups with bacteraemia.

Multidrug-resistant, gram-negative infections in high-risk haematologic patients: an update on epidemiology, diagnosis and treatment

PURPOSE OF REVIEW

Multidrug-resistant Gram-negative bacilli (MDR-GNB) infections are a significant cause of morbidity and mortality in high-risk hematologic patients. Early diagnosis and management of antibiotic treatment in these patients is a challenge for physicians. This review focuses on the latest literature reports that concern the epidemiology, diagnosis and treatment of MDR-GNB infections in this population.

RECENT FINDINGS

High-risk haematological patients have several risk factors that make them particularly susceptible to MDR-GNB infections. Few studies have examined the implementation of rapid diagnostic methods for multidrug resistance, and their impact on management in this population. Inappropriate empiric antibiotic treatment in these patients has been described frequently and is associated with poor outcomes.

SUMMARY

Knowledge of the local epidemiology of MDR-GNB is a basic requirement to guide empiric antibiotic treatments in each centre. New diagnosic tests might help in faster identification of MDR-GNB infections. Appropriate empiric antibiotic treatment is crucial for improving patients' prognosis. Important strategies to reduce inadequate antibiotic treatment include better risk stratification for MDR-GNB infection and the introduction of new, more broad-spectrum antibiotic therapies.

It's Not Easy Being Green: A Narrative Review on the Microbiology, Virulence and Therapeutic Prospects of Multidrug-Resistant Pseudomonas aeruginosa

Pseudomonas aeruginosa is the most frequent cause of infection among non-fermenting Gram-negative bacteria, predominantly affecting immunocompromised patients, but its pathogenic role should not be disregarded in immunocompetent patients. These pathogens present a concerning therapeutic challenge to clinicians, both in community and in hospital settings, due to their increasing prevalence of resistance, and this may lead to prolonged therapy, sequelae, and excess mortality in the affected patient population. The resistance mechanisms of P. aeruginosa may be classified into intrinsic and acquired resistance mechanisms. These mechanisms lead to occurrence of resistant strains against important antibiotics-relevant in the treatment of P. aeruginosa infections-such as β-lactams, quinolones, aminoglycosides, and colistin. The occurrence of a specific resistotype of P. aeruginosa, namely the emergence of carbapenem-resistant but cephalosporin-susceptible (Car-R/Ceph-S) strains, has received substantial attention from clinical microbiologists and infection control specialists; nevertheless, the available literature on this topic is still scarce. The aim of this present review paper is to provide a concise summary on the adaptability, virulence, and antibiotic resistance of P. aeruginosa to a readership of basic scientists and clinicians.