Ceftolozane/tazobactam: place in therapy

Evaluating Cefiderocol in the Treatment of Multidrug-Resistant Gram-Negative Bacilli: A Review of the Emerging Data

Infections due to multidrug-resistant Gram-negative bacteria (MDR-GNB), especially when carbapenem resistant, have been very difficult to manage in the last fifteen years, owing to the paucity of dependable therapeutic options. Cefiderocol is a siderophore cephalosporin recently approved by the Food and Drug Administration (FDA) and European Medicines Agency (EMA) that may have the potential to fill some of the remaining gaps in the treatment of MDR-GNB infections. Among others, cefiderocol demonstrated in vitro activity against carbapenem-resistant Acinetobacter baumannii and metallo-β-lactamases producers. Clinical data from both registrative studies and post-marketing experiences are essential to confirm whether these promises from in vitro studies could readily translate into clinical practice, as well as to delineate the precise place in therapy for cefiderocol for the treatment of MDR-GNB in the near future. Because of its unique potential, it is essential to provide both randomized controlled trials (RCT) and real-life data to improve the ability of clinicians to exploit its benefit in both empirical and targeted treatment of MDR-GNB infections. In this narrative review, we discuss the emerging data from pivotal RCT and initial real-life experiences on the use of cefiderocol for the treatment of MDR-GNB infections.

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

PURPOSE OF REVIEW

The widespread diffusion of extended-spectrum β-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 β-lactams/β-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/β-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.

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 β-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.

Resistance to Novel β-Lactam-β-Lactamase Inhibitor Combinations: The "Price of Progress"

Significant advances were made in antibiotic development during the past 5 years. Novel agents were added to the arsenal that target critical priority pathogens, including multidrug-resistant Pseudomonas aeruginosa and carbapenem-resistant Enterobacterales. Of these, 4 novel β-lactam-β-lactamase inhibitor combinations (ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, and imipenem-cilastatin-relebactam) reached clinical approval in the United States. With these additions comes a significant responsibility to reduce the possibility of emergence of resistance. Reports in the rise of resistance toward ceftolozane-tazobactam and ceftazidime-avibactam are alarming. Clinicians and scientists must make every attempt to reverse or halt these setbacks.

Treatment of Bloodstream Infections Due to Gram-Negative Bacteria with Difficult-to-Treat Resistance

The rising incidence of bloodstream infections (BSI) due to Gram-negative bacteria (GNB) with difficult-to-treat resistance (DTR) has been recognized as a global emergency. The aim of this review is to provide a comprehensive assessment of the mechanisms of antibiotic resistance, epidemiology and treatment options for BSI caused by GNB with DTR, namely extended-spectrum Beta-lactamase-producing Enterobacteriales; carbapenem-resistant Enterobacteriales; DTR Pseudomonas aeruginosa; and DTR Acinetobacter baumannii.

ESBLs and resistance to ceftazidime/avibactam and ceftolozane/tazobactam combinations in Escherichia coli and Pseudomonas aeruginosa

OBJECTIVES

To evaluate the efficacy of the recently launched β-lactam/β-lactamase inhibitor combinations ceftazidime/avibactam and ceftolozane/tazobactam against ESBL-producing Escherichia coli and Pseudomonas aeruginosa strains.

METHODS

A series of ESBL-encoding genes (blaTEM, blaSHV, blaCTX-M, blaVEB, blaPER, blaGES and blaBEL) was cloned and expressed in E. coli or P. aeruginosa recipient strains. Cultures of E. coli TOP10 harbouring recombinant plasmids and therefore producing the different ESBLs tested were grown in order to perform measurements of catalytic activities, using benzylpenicillin, ceftazidime and ceftolozane as substrates. IC50s were additionally determined for clavulanic acid, tazobactam and avibactam.

RESULTS

We showed here an overall better activity of ceftazidime/avibactam compared with ceftolozane/tazobactam toward ESBL-producing E. coli and P. aeruginosa. Several ESBLs of the GES, PER and BEL types conferred resistance to ceftolozane/tazobactam in E. coli and P. aeruginosa. For GES-6 and PER-1 producers, resistance to ceftolozane/tazobactam could be explained by a high hydrolysis of ceftolozane and a low activity of tazobactam as an inhibitor. On the other hand, PER-producing P. aeruginosa also exhibited resistance to ceftazidime/avibactam.

CONCLUSIONS

Altogether, the results show that the ESBL PER-1, which is widespread worldwide, may be a source of resistance to both ceftolozane/tazobactam and ceftazidime/avibactam. Excellent activity of ceftazidime/avibactam was highlighted for both ESBL-producing E. coli and ESBL-producing P. aeruginosa.

The role of fosfomycin for multidrug-resistant gram-negative infections

PURPOSE OF REVIEW

In the last decade, an increasing interest in using fosfomycin for the treatment of multidrug-resistant gram-negative (MDR-GNB) infections have been registered, especially when none or only a few other active alternatives remained available.

RECENT FINDINGS

Fosfomycin may remain active against a considerable proportion of MDR-GNB. In observational studies, a possible curative effect of oral fosfomycin monotherapy has been described for uncomplicated urinary tract infections (UTI) and bacterial prostatitis caused by MDR-GNB, whereas intravenous fosfomycin has been mostly used in combination with other agents for various type of severe MDR-GNB infections. The ZEUS randomized controlled trial (RCT) has started to provide high-level evidence about the possible use of fosfomycin for complicated UTI caused by extended-spectrum β-lactamase-producing GNB, but no results of large RCT are currently available to firmly guide the use of fosfomycin for carbapenem-resistant GNB.

SUMMARY

Fosfomycin is an important therapeutic option for MDR-GNB infections. Further pharmacokinetic/pharmacodynamic and clinical research is needed to optimize its use.

Recent advances in the development of β-lactamase inhibitors

β-Lactam antibiotics are the most commonly prescribed antibiotics worldwide; however, antimicrobial resistance (AMR) is a global challenge. The β-lactam resistance in Gram-negative bacteria is due to the production of β-lactamases, including extended-spectrum β-lactamases, metallo-β-lactamases, and carbapenem-hydrolyzing class D β-lactamases. To restore the efficacy of BLAs, the most successful strategy is to use them in combination with β-lactamase inhibitors (BLI). Here we review the medically relevant β-lactamase families and penicillins, diazabicyclooctanes, boronic acids, and novel chemical scaffold-based BLIs, in particular approved and under clinical development.

New cephalosporins for the treatment of pneumonia in internal medicine wards

The burden of hospital admission for pneumonia in internal medicine wards may not be underestimated; otherwise, cases of pneumonia are a frequent indication for antimicrobial prescriptions. Community- and hospital-acquired pneumonia are characterized by high healthcare costs, morbidity and non-negligible rates of fatality. The overcoming prevalence of resistant gram-negative and positive bacteria (e.g., methicillin-resistant Staphylococcus aureus, penicillin and ceftriaxone-resistant Streptococcus pneumoniae, extended-spectrum β-lactamases and carbapenemases producing Enterobacteriaceae) has made the most of the first-line agents ineffective for treating lower respiratory tract infections. A broad-spectrum of activity, favourable pulmonary penetration, harmlessness and avoiding in some cases a combination therapy, characterise new cephalosporins such as ceftolozane/tazobactam, ceftobiprole, ceftazidime/avibactam and ceftaroline. We aimed to summarise the role and place in therapy of new cephalosporins in community- and hospital-acquired pneumonia within the setting of internal medicine wards. The "universal pneumonia antibiotic strategy" is no longer acceptable for treating lung infections. Antimicrobial therapy should be individualized considering local antimicrobial resistance and epidemiology, the stage of the illness and potential host factors predisposing to a high risk for specific pathogens.

Multidrug Resistance (MDR) and Collateral Sensitivity in Bacteria, with Special Attention to Genetic and Evolutionary Aspects and to the Perspectives of Antimicrobial Peptides-A Review

Antibiotic poly-resistance (multidrug-, extreme-, and pan-drug resistance) is controlled by adaptive evolution. Darwinian and Lamarckian interpretations of resistance evolution are discussed. Arguments for, and against, pessimistic forecasts on a fatal “post-antibiotic era” are evaluated. In commensal niches, the appearance of a new antibiotic resistance often reduces fitness, but compensatory mutations may counteract this tendency. The appearance of new antibiotic resistance is frequently accompanied by a collateral sensitivity to other resistances. Organisms with an expanding open pan-genome, such as Acinetobacter baumannii, Pseudomonas aeruginosa, and Klebsiella pneumoniae, can withstand an increased number of resistances by exploiting their evolutionary plasticity and disseminating clonally or poly-clonally. Multidrug-resistant pathogen clones can become predominant under antibiotic stress conditions but, under the influence of negative frequency-dependent selection, are prevented from rising to dominance in a population in a commensal niche. Antimicrobial peptides have a great potential to combat multidrug resistance, since antibiotic-resistant bacteria have shown a high frequency of collateral sensitivity to antimicrobial peptides. In addition, the mobility patterns of antibiotic resistance, and antimicrobial peptide resistance, genes are completely different. The integron trade in commensal niches is fortunately limited by the species-specificity of resistance genes. Hence, we theorize that the suggested post-antibiotic era has not yet come, and indeed might never come.

Multicentre study of the in vitro activity of ceftolozane/tazobactam and other commonly used antibiotics against Pseudomonas aeruginosa isolates from patients in the UK

Objectives

To evaluate the in vitro activity of ceftolozane/tazobactam and other commonly used antipseudomonal antibiotics against geographically spread Pseudomonas aeruginosa isolates in the UK using disc susceptibility testing.

Methods

The in vitro activity of ceftolozane/tazobactam and nine other commonly used antipseudomonal antibiotics was evaluated. Isolates were collected between January 2015 and April 2018. Susceptibility results were interpreted using EUCAST 2018 criteria.

Results

Overall, 1326 clinical isolates from 14 centres in the UK were tested. The majority of the isolates were collected from non-cystic fibrosis (non-CF) patients (n = 1123, 85.0%). In addition, 199 cystic fibrosis (CF) isolates were collected from 10 centres. Overall susceptibility to ceftolozane/tazobactam was 89.3% (n = 1181), which included 128 CF and 1053 non-CF isolates. The other antibacterial agents with the highest susceptibility were tobramycin (92.4%, n = 1221) and piperacillin/tazobactam (90.7%, n = 1199). Susceptibility to all antibacterial agents was lower for CF isolates. Piperacillin/tazobactam was the most active of the antibacterial agents tested, followed by ceftolozane/tazobactam (70.4% and 64.3%, respectively), and <60% of CF isolates were susceptible to ceftazidime and the carbapenems. The reason for the higher rates of susceptibility to piperacillin/tazobactam and lower susceptibility to ceftazidime compared with other studies is unclear.

Conclusions

The data presented here support the need to investigate the place of ceftolozane/tazobactam as a treatment option in the management of pseudomonal infections, particularly in patients with CF. The results highlight the importance of routine testing of new antibacterial agents and of making the data available to clinicians to make appropriate and informed treatment choices.

Antimicrobial Activity of Ceftolozane-Tazobactam and Comparators against Clinical Isolates of Haemophilus influenzae from the United States and Europe

Nine hundred Haemophilus influenzae clinical isolates from 83 U.S. and European medical centers were tested for susceptibility by reference broth microdilution methods against ceftolozane-tazobactam and comparators. Results were stratified by β-lactamase production and infection type. Overall, ceftolozane-tazobactam MIC_50/90 values were 0.12/0.25 mg/liter, and 99.0% of isolates were inhibited at the susceptible breakpoint of ≤0.5 mg/liter; the highest MIC value was only 2 mg/liter. Our results support using ceftolozane-tazobactam to treat H. influenzae infections.

Ceftolozane/Tazobactam for Treatment of Severe ESBL-Producing Enterobacterales Infections: A Multicenter Nationwide Clinical Experience (CEFTABUSE II Study)

Background

Few data are reported in the literature about the outcome of patients with severe extended-spectrum β-lactamase-producing Enterobacterales (ESBL-E) infections treated with ceftolozane/tazobactam (C/T), in empiric or definitive therapy.

Methods

A multicenter retrospective study was performed in Italy (June 2016-June 2019). Successful clinical outcome was defined as complete resolution of clinical signs/symptoms related to ESBL-E infection and lack of microbiological evidence of infection. The primary end point was to identify predictors of clinical failure of C/T therapy.

Results

C/T treatment was documented in 153 patients: pneumonia was the most common diagnosis (n = 46, 30%), followed by 34 cases of complicated urinary tract infections (22.2%). Septic shock was observed in 42 (27.5%) patients. C/T was used as empiric therapy in 46 (30%) patients and as monotherapy in 127 (83%) patients. Favorable clinical outcome was observed in 128 (83.7%) patients; 25 patients were considered to have failed C/T therapy. Overall, 30-day mortality was reported for 15 (9.8%) patients. At multivariate analysis, Charlson comorbidity index >4 (odds ratio [OR], 2.3; 95% confidence interval [CI], 1.9-3.5; P = .02), septic shock (OR, 6.2; 95% CI, 3.8-7.9; P < .001), and continuous renal replacement therapy (OR, 3.1; 95% CI, 1.9-5.3; P = .001) were independently associated with clinical failure, whereas empiric therapy displaying in vitro activity (OR, 0.12; 95% CI, 0.01-0.34; P < .001) and adequate source control of infection (OR, 0.42; 95% CI, 0.14-0.55; P < .001) were associated with clinical success.

Conclusions

Data show that C/T could be a valid option in empiric and/or targeted therapy in patients with severe infections caused by ESBL-producing Enterobacterales. Clinicians should be aware of the risk of clinical failure with standard-dose C/T therapy in septic patients receiving CRRT.

An overview of ceftolozane sulfate + tazobactam for treating hospital acquired pneumonia

INTRODUCTION

Ceftolozane-tazobactam is a combination of a new cephalosporin, with activity similar to that of ceftazidime, and a known inhibitor of beta-lactamases. This compound shows excellent activity against most gram-negative organisms causative of hospital-acquired pneumonia (HAP) or ventilator-acquired pneumonia (VAP), including extended spectrum beta-lactamase (ESBL)-producing Enterobacterales and multidrug-resistant (MDR) Pseudomonas aeruginosa.

AREAS COVERED

This article reviews the spectrum of activity, the main pharmacokinetic and pharmacodynamic characteristics and the clinical efficacy and safety of ceftolozane-tazobactam in the treatment of HAP/VAP in adult patients.

EXPERT OPINION

The results of a randomized clinical trial have demonstrated an efficacy and safety profile of ceftolozane-tazobactam similar to that of its comparator for the treatment of patients with HAP/VAP. Several retrospective studies have shown good efficacy of the drug for the treatment of respiratory infections caused by MDR P. aeruginosa. The use of this drug may be incorporated as a new therapeutic option for the treatment of patients with HAP/VAP in a carbapenem-saving setting or as a therapeutic alternative with a better safety profile than other therapeutic options in patients with infections caused by MDR P. aeruginosa.

Use of colistin in adult patients: A cross-sectional study

OBJECTIVES

The aim of this study was to assess colistin use in a country endemic for multidrug-resistant Gram-negative bacteria (MDR-GNB).

METHODS

Colistin prescription patterns were evaluated in 22 Italian centres. Factors associated with use of colistin in combination with other anti-MDR-GNB agents were also assessed.

RESULTS

A total of 221 adults receiving colistin were included in the study. Their median age was 64 years (interquartile range 52-73 years) and 134 (61%) were male. Colistin was mostly administered intravenously (203/221; 92%) and mainly for targeted therapy (168/221; 76%). The most frequent indications for colistin therapy were bloodstream infection and lower respiratory tract infection. Intravenous colistin was administered in combination with at least another anti-MDR-GNB agent in 80% of cases (163/203). A loading dose of 9 MU of colistimethate was administered in 79% of patients receiving i.v. colistin and adequate maintenance doses in 85%. In multivariable analysis, empirical therapy [odds ratio (OR) = 3.25, 95% confidence interval (CI) 1.24-8.53;P = 0.017] and targeted therapy for carbapenem-resistant Enterobacterales infection (OR = 4.76, 95% CI 1.69-13.43; P = 0.003) were associated with use of colistin in combination with other agents, whilst chronic renal failure (OR = 0.39, 95% CI 0.17-0.88; P =  0.024) was associated with use of colistin monotherapy.

CONCLUSION

Colistin remains an important option for severe MDR-GNB infections when other treatments are not available. Despite inherent difficulties in optimising its use owing to peculiar pharmacokinetic/pharmacodynamic characteristics, colistin was mostly used appropriately in a country endemic for MDR-GNB.

Carbapenem-Resistant Gram-Negative Bacterial Infections in Children

Carbapenem-resistant organisms (CRO) are a major global public health threat. Enterobacterales hydrolyze almost all β-lactams through carbapenemase production. Infections caused by CRO are challenging to treat due to the limited number of antimicrobial options. This leads to significant morbidity and mortality. Over the last few years, several new antibiotics effective against CRO have been approved. Some of them (e.g., plazomicin or imipenem-cilastatin-relebactam) are currently approved for use only by adults; others (e.g., ceftazidime-avibactam) have recently been approved for use by children. Recommendations for antibiotic therapy of CRO infections in pediatric patients are based on evidence mainly from adult studies. The availability of pediatric pharmacokinetic and safety data is the cornerstone to broaden the use of proposed agents in adults to the pediatric population. This article provides a comprehensive review of the current knowledge regarding infections caused by CRO with a focus on children, which includes epidemiology, risk factors, outcomes, and antimicrobial therapy management, with particular attention being given to new antibiotics.

Carbapenem-Sparing Strategies for ESBL Producers: When and How

Extended spectrum β-lactamase (ESBL)-producing bacteria are prevalent worldwide and correlated with hospital infections, but they have been evolving as an increasing cause of community acquired infections. The spread of ESBL constitutes a major threat for public health, and infections with ESBL-producing organisms have been associated with poor outcomes. Established therapeutic options for severe infections caused by ESBL-producing organisms are considered the carbapenems. However, under the pressure of carbapenem overuse and the emergence of resistance, carbapenem-sparing strategies have been implemented. The administration of carbapenem-sparing antibiotics for the treatment of ESBL infections has yielded conflicting results. Herein, the current available knowledge regarding carbapenem-sparing strategies for ESBL producers is reviewed, and the optimal conditions for the "when and how" of carbapenem-sparing agents is discussed. An important point of the review focuses on piperacillin-tazobactam as the agent arousing the most debate. The most available data regarding non-carbapenem β-lactams (i.e., ceftolozane-tazobactam, ceftazidime-avibactam, temocillin, cephamycins and cefepime) are also thoroughly presented as well as non β-lactams (i.e., aminoglycosides, quinolones, tigecycline, eravacycline and fosfomycin).

Ceftazidime/Avibactam and Ceftolozane/Tazobactam for Multidrug-Resistant Gram Negatives in Patients with Hematological Malignancies: Current Experiences

Patients suffering from hematological malignancies are at high risk for severe infections, including in particular bloodstream infections, which represent one of the most frequent life-threatening complications for these patients, with reported mortality rates reaching 40%. Furthermore, a worrisome increase in antimicrobial resistance of Gram-negative bacteria (e.g., cephalosporin- and/or carbapenem-resistant Enterobacteriaceae and multidrug-resistant (MDR) Pseudomonas aeruginosa) involved in severe infectious complications among patients with hematological malignancies has been reported during the last years. The two novel combination of cephalosporins and β-lactamase inhibitors, ceftolozane/tazobactam and ceftazidime/avibactam, were recently approved for treatment of complicated intra-abdominal and urinary tract infections and nosocomial pneumonia and display activity against several MDR Gram-negative strains. Although not specifically approved for neutropenic and/or cancer patients, these drugs are used in this setting due to increasing rates of infections caused by MDR Gram-negative bacteria. The aim of this review is to describe the actual evidence from scientific literature about the "real-life" use of these two novel drugs in patients with hematological malignancies and infections caused by MDR Gram-negative bacteria.

Machine Learning and Multidrug-Resistant Gram-Negative Bacteria: An Interesting Combination for Current and Future Research

The dissemination of multidrug-resistant Gram-negative bacteria (MDR-GNB) is associated with increased morbidity and mortality in several countries. Machine learning (ML) is a branch of artificial intelligence that consists of conferring on computers the ability to learn from data. In this narrative review, we discuss three existing examples of the application of ML algorithms for assessing three different types of risk: (i) the risk of developing a MDR-GNB infection, (ii) the risk of MDR-GNB etiology in patients with an already clinically evident infection, and (iii) the risk of anticipating the emergence of MDR in GNB through the misuse of antibiotics. In the next few years, we expect to witness an increasingly large number of research studies perfecting the application of ML techniques in the field of MDR-GNB infections. Very importantly, this cannot be separated from the availability of a continuously refined and updated ethical framework allowing an appropriate use of the large datasets of medical data needed to build efficient ML-based support systems that could be shared through appropriate standard infrastructures.

Ceftolozane/Tazobactam for Treating Children With Exacerbations of Cystic Fibrosis Due to Pseudomonas aeruginosa: A Review of Available Data

Ceftolozane-tazobactam is a novel fifth-generation cephalosporin/β-lactamase inhibitor combination recently approved for treatment of both complicated intra-abdominal and urinary tract infections in adults. Considering its potent bactericidal activity against Pseudomonas aeruginosa, it might represent an important option also for treating children with exacerbations of cystic fibrosis due to Pseudomonas aeruginosa when other alternative treatments have been exhausted. We hereby review available data on the use of ceftolozane-tazobactam in children, focusing on cystic fibrosis.

Preventing sepsis development in complicated urinary tract infections

Introduction: Urinary tract infections (UTIs) are the most prevalent infections in the community and the most common reason for antimicrobial prescribing in ambulatory care. A UTI is defined as complicated when urinary tract anatomical abnormalities or urinary devices are present, when it is recurrent and when associated with immunodeficiency. Complicated UTIs (cUTIs) have a higher risk of treatment failure and often require longer antimicrobial treatment courses. cUTIs, especially those which are healthcare-associated, are often due to multidrug resistant organisms (MDROs).Areas covered: This article will review the available evidence in relation to prevention of sepsis in cUTI, evaluating the risk factors associated with sepsis development. Published articles from January 2005 to September 2019 on UTIs and sepsis prevention in complicated UTIs were identified by using MEDLINE (National Library of Medicine Bethesda MD) and by reviewing the references of retrieved articles.Expert opinion: Prevention of sepsis relies on prompt and timely diagnosis of cUTI, early identification of the causative organism, removal of obstructions and source control, proper and adequate empirical/targeted antimicrobial treatment. In particular, source control, i.e. removal of urinary obstructions, infected stents, urinary catheters, nephrostomies, and drainage of hydronephrosis/abscess, is essential for preventing the development and progression of sepsis.

The latest advances in β-lactam/β-lactamase inhibitor combinations for the treatment of Gram-negative bacterial infections

Introduction: Antimicrobial resistance in Gram-negative pathogens is a significant threat to global health. β-Lactams (BL) are one of the safest and most-prescribed classes of antibiotics on the market today. The acquisition of β-lactamases, especially those which hydrolyze carbapenems, is eroding the efficacy of BLs for the treatment of serious infections. During the past decade, significant advances were made in the development of novel BL-β-lactamase inhibitor (BLI) combinations to target β-lactamase-mediated resistant Gram-negatives.Areas covered: The latest progress in 20 different approved, developing, and preclinical BL-BLI combinations to target serine β-lactamases produced by Gram-negatives are reviewed based on primary literature, conference abstracts (when available), and US clinical trial searches within the last 5 years. The majority of the compounds that are discussed are being evaluated as part of a BL-BLI combination.Expert opinion: The current trajectory in BLI development is promising; however, a significant challenge resides in the selection of an appropriate BL partner as well as the development of resistance linked to the BL partner. In addition, dosing regimens for these BL-BLI combinations need to be critically evaluated. A revolution in bacterial diagnostics is essential to aid clinicians in the appropriate selection of novel BL-BLI combinations for the treatment of serious infections.

Post-operative abdominal infections: epidemiology, operational definitions, and outcomes

Postoperative abdominal infections are an important and heterogeneous health challenge in intensive care units (ICU) and encompass postoperative infectious processes developing within the abdominal cavity that may be caused by either bacterial or fungal pathogens. In this narrative review, we discuss postoperative bacterial and fungal abdominal infections, covering also multidrug-resistant (MDR) pathogens. We also cover clinically preeminent aspects such as the definition of postoperative abdominal infections, which still remains difficult owing to their heterogeneity in patient characteristics, clinical presentation, ecology and antimicrobial treatment. With regard to treatment, modifiable factors such as source control and antimicrobial therapy play a key role in influencing the prognosis of postoperative abdominal infections, but several conditions may hamper their correct application; thus efforts should necessarily be devoted towards improving their appropriateness and timing. Hot topics regarding the characteristics and management of postoperative abdominal infections are discussed in this narrative review.

Rational approach in the management of Pseudomonas aeruginosa infections

PURPOSE OF REVIEW

This review details the management of Pseudomonas aeruginosa infections covering both current and future treatment options that are and may be available for the clinicians.

RECENT FINDINGS

Pseudomonas aeruginosa infections are a great concern in hospital-acquired infections with very limited therapeutic options. The increasing antibiotic resistance has led to a need for different treatment choices that range from the use of new antibiotics to new nonantibiotic alternative agents to kill or disarm the pathogen.

SUMMARY

New molecules such as ceftolozane-tazobactam, ceftazidime-avibactam, and imipenem-relebactam have shown an adequate activity against P. aeruginosa, especially against multidrug resistance strains. Other nonantibiotic alternative treatments, such as antibodies, bacteriocins or phage therapy, have shown promising results, but future clinical studies are needed.

Population Pharmacokinetics of Unbound Ceftolozane and Tazobactam in Critically Ill Patients without Renal Dysfunction

Evaluation of dosing regimens for critically ill patients requires pharmacokinetic data in this population. This prospective observational study aimed to describe the population pharmacokinetics of unbound ceftolozane and tazobactam in critically ill patients without renal impairment and to assess the adequacy of recommended dosing regimens for treatment of systemic infections. Patients received 1.5 or 3.0 g ceftolozane-tazobactam according to clinician recommendation.

Evaluation of dosing regimens for critically ill patients requires pharmacokinetic data in this population. This prospective observational study aimed to describe the population pharmacokinetics of unbound ceftolozane and tazobactam in critically ill patients without renal impairment and to assess the adequacy of recommended dosing regimens for treatment of systemic infections. Patients received 1.5 or 3.0 g ceftolozane-tazobactam according to clinician recommendation. Unbound ceftolozane and tazobactam plasma concentrations were assayed, and data were analyzed with Pmetrics with subsequent Monte Carlo simulations. A two-compartment model adequately described the data from twelve patients. Urinary creatinine clearance (CL_CR) and body weight described between-patient variability in clearance and central volume of distribution (V), respectively. Mean ± standard deviation (SD) parameter estimates for unbound ceftolozane and tazobactam, respectively, were CL of 7.2 ± 3.2 and 25.4 ± 9.4 liters/h, V of 20.4 ± 3.7 and 32.4 ± 10 liters, rate constant for distribution of unbound ceftolozane or tazobactam from central to peripheral compartment (Kcp) of 0.46 ± 0.74 and 2.96 ± 8.6 h⁻¹, and rate constant for distribution of unbound ceftolozane or tazobactam from peripheral to central compartment (Kpc) of 0.39 ± 0.37 and 26.5 ± 8.4 h⁻¹. With dosing at 1.5 g and 3.0 g every 8 h (q8h), the fractional target attainment (FTA) against Pseudomonas aeruginosa was ≥85% for directed therapy (MIC ≤ 4 mg/liter). However, for empirical coverage (MIC up to 64 mg/liter), the FTA was 84% with the 1.5-g q8h regimen when creatinine clearance is 180 ml/min/1.73 m², whereas the 3.0-g q8h regimen consistently achieved an FTA of ≥85%. For a target of 40% of time the free drug concentration is above the MIC (40% fT_>MIC), 3g q8h by intermittent infusion is suggested unless a highly susceptible pathogen is present, in which case 1.5-g dosing could be used. If a higher target of 100% fT_>MIC is required, a 1.5-g loading dose plus a 4.5-g continuous infusion may be adequate.

Challenges and research priorities to progress the impact of antimicrobial stewardship

Antimicrobial stewardship programmes have been playing an important role in patient care and hospital policies. These programmes are now recognised as formal strategies for curbing the upward trend in antibiotic resistance and for improving the appropriate antimicrobial and antifungal use. The role of such programs in the era of antimicrobial resistance presents several unique challenges and opportunities, most notably in the diagnostic and therapeutic setting. Controversies remain regarding the most effective interventions and the appropriate design to evaluate their impact. In this review, based on rounds of discussion, we explain the most important challenges faced by antibiotic stewardship and antifungal stewardship programmes. We also try to suggest areas for further research.

Risk stratification and treatment of ICU-acquired pneumonia caused by multidrug- resistant/extensively drug-resistant/pandrug-resistant bacteria

PURPOSE OF REVIEW

Describe the risk factors and discuss the management of multidrug-resistant (MDR) bacteria responsible for pneumonia among critically ill patients, including methicillin-resistant Staphylococcus aureus, extended spectrum beta-lactamase-producing Enterobactericeae, carbapenem-resistant Enterobactericeae, multidrug resistant Pseudomonas aeruginosa, and Acinetobacter baumannii.

RECENT FINDINGS

Multiple factors have been associated with infections because of MDR bacteria, including prolonged hospital stay, presence of invasive devices, mechanical ventilation, colonization with resistant pathogens, and use of broad-spectrum antibiotics. Management of these infections includes the prompt use of appropriate antimicrobial therapy, implementation of antimicrobial stewardship protocols, and targeted active microbiology surveillance. Combination therapy and novel molecules have been used for the treatment of severe infections caused by resistant bacteria.

SUMMARY

The exponential increase of antimicrobial resistance among virulent pathogens currently represents one of the main challenges for clinicians in the intensive care unit. Knowledge of the local epidemiology, patient risk stratification, and infection-control policies remain key elements for the management of MDR infections. Results from clinical trials on new molecules are largely awaited.

The "Old" and the "New" Antibiotics for MDR Gram-Negative Pathogens: For Whom, When, and How

The recent expansion of multidrug resistant and pan-drug-resistant pathogens poses significant challenges in the treatment of healthcare associated infections. An important advancement, is a handful of recently launched new antibiotics targeting some of the current most problematic Gram-negative pathogens, namely carbapenem-producing Enterobacteriaceae (CRE) and carbapenem-resistant P. aeruginosa (CRPA). Less options are available against carbapenem-resistant Acinetobacter baumannii (CRAB) and strains producing metallo-beta lactamases (MBL). Ceftazidime-avibactam signaled a turning point in the treatment of KPC and partly OXA- type carbapenemases, whereas meropenem-vaborbactam was added as a potent combination against KPC-producers. Ceftolozane-tazobactam could be seen as an ideal beta-lactam backbone for the treatment of CRPA. Plazomicin, an aminoglycoside with better pharmacokinetics and less toxicity compared to other class members, will cover important proportions of multi-drug resistant pathogens. Eravacycline holds promise in the treatment of infections by CRAB, with a broad spectrum of activity similar to tigecycline, and improved pharmacokinetics. Novel drugs and combinations are not to be considered "panacea" for the ongoing crisis in the therapy of XDR Gram-negative bacteria and colistin will continue to be considered as a fundamental companion drug for the treatment of carbapenem-resistant Enterobacteriaceae (particularly in areas where MBL predominate), for the treatment of CRPA (in many cases being the only in vitro active drug) as well as CRAB. Aminoglycosides are still important companion antibiotics. Finally, fosfomycin as part of combination treatment for CRE infections and P. aeruginosa, deserves a greater attention. Optimal conditions for monotherapy and the "when and how" of combination treatments integrating the novel agents will be discussed.

Use of Ceftolozane/Tazobactam in a Case of Septic Shock by Puerperal Sepsis

Multiresistant bacteria infections cause widespread morbidity and mortality and lead to an increase in expenses for hospital stays and complications. We describe the case of a 27-year-old patient with puerperal sepsis after cesarean section due to Escherichia coli complicated by multiresistant Klebsiella ESBL-producing superinfection with septic shock and multiple organ dysfunction syndrome, successfully treated with ceftolozane/tazobactam.

Donor-derived infections, lessons learnt from the past, and what is the future going to bring us

PURPOSE OF REVIEW

Donor-derived transmission of infectious diseases is a well-recognized complication of solid organ transplantation (SOT). Most donor-derived disease transmissions are expected. Although uncommon, unexpected donor-derived infections can be associated with significant morbidity and mortality, and as the volume of patients undergoing SOT increases, the number of infections transmitted through organ donation can also be expected to rise. The growing gap between the number of patients waiting for transplantation and available organs continue in fact to be the number one issue facing the transplant community. As a consequence the major focus in organ transplantation has been developing strategies to increase the available organs, including the use of organs from donors with infections or risky behaviors that have disqualified them from the donation in the past.

RECENT FINDINGS

In addition to the commonly reported donor-derived transmissions, an increasing number of studies have reported unusual infections transmitted by SOT.

SUMMARY

Transplant surgeons and physicians should increase their awareness toward uncommon donor-derived infections including them in the differential diagnosis of unusual clinical pictures in their recipients.

Treatment of Infections Due to MDR Gram-Negative Bacteria

The treatment of multidrug-resistant Gram-negative bacteria (MDR-GNB) infections in critically ill patients presents many challenges. Since an effective treatment should be administered as soon as possible, resistance to many antimicrobial classes almost invariably reduces the probability of adequate empirical coverage, with possible unfavorable consequences. In this light, readily available patient's medical history and updated information about the local microbiological epidemiology remain critical for defining the baseline risk of MDR-GNB infections and firmly guiding empirical treatment choices, with the aim of avoiding both undertreatment and overtreatment. Rapid diagnostics and efficient laboratory workflows are also of paramount importance both for anticipating diagnosis and for rapidly narrowing the antimicrobial spectrum, with de-escalation purposes and in line with antimicrobial stewardship principles. Carbapenem-resistant Enterobacteriaceae, Pseudomonas aeruginosa, and Acinetobacter baumannii are being reported with increasing frequencies worldwide, although with important variability across regions, hospitals and even single wards. In the past few years, new treatment options, such as ceftazidime/avibactam, meropenem/vaborbactam, ceftolozane/tazobactam, plazomicin, and eravacycline have become available, and others will become soon, which have provided some much-awaited resources for effectively counteracting severe infections due to these organisms. However, their optimal use should be guaranteed in the long term, for delaying as much as possible the emergence and diffusion of resistance to novel agents. Despite important progresses, pharmacokinetic/pharmacodynamic optimization of dosages and treatment duration in critically ill patients has still some areas of uncertainty requiring further study, that should take into account also resistance selection as a major endpoint. Treatment of severe MDR-GNB infections in critically ill patients in the near future will require an expert and complex clinical reasoning, of course taking into account the peculiar characteristics of the target population, but also the need for adequate empirical coverage and the more and more specific enzyme-level activity of novel antimicrobials with respect to the different resistance mechanisms of MDR-GNB.

Current and emerging pharmacotherapy for the treatment of infections following open-heart surgery

INTRODUCTION

Patients undergoing open-heart surgery may suffer from postoperative complications, including severe infections. Antimicrobials to treat infectious complications in this population should be selected thoughtfully, taking into account three different and fundamental issues: (i) the site of infection; (ii) the suspected or proven causative agent and its susceptibility pattern; and (iii) the risk of suboptimal pharmacokinetic characteristics and potential toxicity of the chosen drug/s.

AREAS COVERED

The present narrative review summarizes the current and future antimicrobial options for the treatment of infections developing after open-heart surgery.

EXPERT OPINION

The pharmacological treatment of infections developing in cardiac surgery patients poses peculiar challenges, including the need for an active empirical therapy for severe events such as bloodstream infections, deep sternal wound infections, or early-onset postoperative prosthetic endocarditis. In addition, the risk for multidrug-resistant pathogens should also be taken into account in endemic areas. A multidisciplinary evaluation on a patient-by-patient basis, deeply involving infectious diseases specialists and cardiothoracic surgeons, remains essential for appropriately balancing both short-term and long-term risks and benefits of any possible surgical reintervention in combination with adequate pharmacotherapy.

Activity of Ceftolozane/Tazobactam Against Gram-Negative Rods of the Family Enterobacteriaceae and Pseudomonas Spp. Isolated from Onco-Hematological Patients Hospitalized in a Clinical Hospital in Poland

Background

The most common etiological agents of infections in onco-hematological patients are Gram-negative rods resistant to many antimicrobials, including carbapenems. Recently, ceftolozane combined with tazobactam became a novel therapeutic option. The aim of the present study was to analyze the susceptibility to ceftolozane/tazobactam of the clinical strains of these bacteria.

Material/Methods

Material comprised rectal swabs, urine, and bronchoalveolar lavage fluid obtained from onco-hematological patients hospitalized in a clinical hospital (1050 beds) in Poland. Identification of the isolated bacteria was done by matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) using the MALDI Biotyper (Bruker). Ceftolozane/tazobactam susceptibility of the isolates was assessed using antimicrobial gradient strips (E-test, BioMérieux). Antimicrobial susceptibility testing and interpretation of the results was done according to the current recommendations of the European Committee on Antimicrobial Susceptibility Testing (EUCAST).

Results

In total, 281 rectal swabs and 116 urine samples were tested for the presence of Gram-negative rods producing ESBL, and 531 rectal swabs and 8 bronchoalveolar lavage fluid samples were tested for the presence of Gram-negative rods resistant to carbapenems. In the analyzed period, 69 non-repetitive strains of bacteria were isolated that were in the spectrum of activity of ceftolozane/tazobactam. Among 44 clinical strains of ESBL(+) Enterobacteriaceae rods, 76% were susceptible to ceftolozane/tazobactam. All 9 strains of non-carbapenemase-producing P. aeruginosa resistant or with decreased susceptibility to carbapenems were susceptible to ceftolozane/tazobactam.

Conclusions

Ceftolozane/tazobactam may be an option in the therapy of infections caused by ESBL(+) strains of Enterobacteriaceae as well as non-carbapenemase-producing carbapenem-resistant strains of P. aeruginosa.

Acquisition of Extended-Spectrum β-Lactamase GES-6 Leading to Resistance to Ceftolozane-Tazobactam Combination in Pseudomonas aeruginosa

A clinical Pseudomonas aeruginosa isolate resistant to all β-lactams, including ceftolozane-tazobactam and carbapenems, was recovered. It belonged to sequence type 235 and produced the extended-spectrum β-lactamase (ESBL) GES-6 differing from GES-1 by two amino acid substitutions (E104K and G170S). GES-6 possessed an increased hydrolytic activity toward carbapenems and to ceftolozane and a decreased susceptibility to β-lactamase inhibitors compared to GES-1, except for avibactam. We show here that resistance to ceftolozane-tazobactam may occur through acquisition of a specific ESBL in P. aeruginosa but that ceftazidime-avibactam combination remains an effective alternative.

An Update in Antimicrobial Therapies and Infection Prevention in Pediatric Lung Transplant Recipients

Lung transplantation can offer life-prolonging therapy to children with otherwise terminal end-stage lung disease. However, infectious complications, like those experienced by their adult counterparts, are a significant cause of morbidity and mortality. These include bacteria, viruses, and fungi that infect the patient pretransplant and those that may be acquired from the donor or by the recipient in the months to years posttransplant. An understanding of the approach to the management of each potential infecting organism is required to ensure optimal outcomes. In particular, emphasis on aggressive preoperative management of infections in pediatric patients with cystic fibrosis is important. These include multidrug-resistant Gram-negative bacteria, fungi, and Mycobacterium abscessus, the posttransplant outcome of which depends on optimal pretransplant management, including vaccination and other preventive, antibiotic-sparing strategies. Similarly, increasing the transplant donor pool to meet rising transplant demands is an issue of critical importance. Expanded-criteria donors-those at increased risk of blood-borne viruses in particular-are increasingly being considered and transplants undertaken to meet the rising demand. There is growing evidence in the adult pool that these transplants are safe and associated with comparable outcomes. Pediatric transplanters are therefore likely to be presented with increased-risk donors for their patients. Finally, numerous novel antibiotic-sparing therapeutic approaches are on the horizon to help combat infections that currently compromise transplant outcomes.

Antimicrobial activity of ceftolozane-tazobactam tested against gram-negative contemporary (2015-2017) isolates from hospitalized patients with pneumonia in US medical centers

Pseudomonas aeruginosa (n = 1531) and Enterobacteriaceae (n = 2373) clinical isolates from hospitalized patients with pneumonia were collected from 31 US medical centers during 2015-2017. Isolates were susceptibility tested against ceftolozane-tazobactam and comparators by broth microdilution. Results from intensive care unit (ICU) patients and patients with ventilator-associated bacterial pneumonia (VABP) were analyzed separately. Ceftolozane-tazobactam was very active against P. aeruginosa (MIC_50/90, 0.5/2 mg/L; 97.5% susceptible), including multidrug-resistant (87.9% susceptible) and extensively drug-resistant (82.9% susceptible). Ceftolozane-tazobactam inhibited 90.3% of Enterobacteriaceae isolates (MIC_50/90, 0.25/2 mg/L), including non-carbapenem-resistant Enterobacteriaceae isolates with an extended-spectrum β-lactamase phenotype (85.7% susceptible). Ceftolozane-tazobactam activity was stable against P. aeruginosa regardless of the US census division or ICU and VABP subsets (>90%); small differences were noted among Enterobacteriaceae isolates from the Middle Atlantic (range 78.3-88.9%) and West South Central (range 86.4-89.2%) divisions. These in vitro results indicate that ceftolozane-tazobactam may represent a valuable option for hospital-acquired bacterial pneumonia and VABP caused by Enterobacteriaceae and P. aeruginosa in the United States.

Ceftolozane/tazobactam for the treatment of serious Pseudomonas aeruginosa infections: a multicentre nationwide clinical experience

This study describes the largest clinical experience using ceftolozane/tazobactam (C/T) for different Pseudomonas aeruginosa infections. A retrospective study was performed at 22 hospitals in Italy (June 2016-March 2018). All adult patients treated with ≥4 days of C/T were enrolled. Successful clinical outcome was defined as complete resolution of clinical signs/symptoms related to P. aeruginosa infection and lack of microbiological evidence of infection. C/T treatment was documented in 101 patients with diverse infections, including nosocomial pneumonia (31.7%), acute bacterial skin and skin-structure infection (20.8%), complicated UTI (13.9%), complicated IAI (12.9%), bone infection (8.9%) and primary bacteraemia (5.9%). Over one-half of P. aeruginosa strains were XDR (50.5%), with 78.2% of isolates resistant to at least one carbapenem. C/T was used as first-line therapy in 39 patients (38.6%). When used as second-line or later, the most common reasons for discontinuation of previous antibiotics were in vitro resistance of P. aeruginosa and clinical failure of previous therapy. Concomitant antibiotics were reported in 35.6% of patients. C/T doses were 1.5 g q8h in 70 patients (69.3%) and 3 g q8h in 31 patients (30.7%); median duration of C/T therapy was 14 days. Overall clinical success was 83.2%. Significant lower success rates were observed in patients with sepsis or receiving continuous renal replacement therapy (CRRT). Mild adverse events were reported in only three patients. C/T demonstrated a favourable safety and tolerability profile regardless of the infection type. Clinicians should be aware of the risk of clinical failure with C/T therapy in septic patients receiving CRRT.

New treatments of multidrug-resistant Gram-negative ventilator-associated pneumonia

Ventilator-associated pneumonia (VAP) remains an important clinical problem globally, being associated with significant morbidity and mortality. As management of VAP requires adequate and timely antibiotic administration, global emergence of antimicrobial resistance poses serious challenges over our ability to maintain this axiom. Development of antimicrobials against MDR Gram-negative pathogens has therefore emerged as a priority and some new antibiotics have been marketed or approach late stage of development. The aim of this review is to analyse new therapeutic options from the point view of potential treatment of VAP. Among recently developed antimicrobials presented herein, it is obvious that we will have promising therapeutic options against VAP caused by Enterobacteriaceae excluding those producing metallo-β-lactamases, against which only cefiderocol and aztreonam/avibactam are expected to be active. Against infections caused by carbapenem non-susceptible Pseudomonas aeruginosa, ceftolozane/tazobactam and to a lesser extend ceftazidime/avibactam may cover a proportion of current medical needs, but there still remain a considerable proportion of strains which harbor other resistance mechanisms. Murepavadin and cefiderocol hold promise against this particularly notorious pathogen. Finally, Acinetobacter baummannii remains a treatment-challenge. Eravacycline, cefiderocol and probably plazomicin seem to be the most promising agents against this difficult-to treat pathogen, but we have still a long road ahead, to see their position in clinical practice and particularly in VAP. In summary, despite persisting and increasing unmet medical needs, several newly approved and forthcoming agents hold promise for the treatment of VAP and hopefully will enrich our antimicrobial arsenal in the next few years. Targeted pharmacokinetic and clinical studies in real-life scenario of VAP are important to position these new agents in clinical practice, whereas vigilant use will ensure their longevity in our armamentarium.

β-lactam/β-lactamase inhibitor combinations: an update

Antibiotic resistance caused by β-lactamase production continues to present a growing challenge to the efficacy of β-lactams and their role as the most important class of clinically used antibiotics. In response to this threat however, only a handful of β-lactamase inhibitors have been introduced to the market over the past thirty years. The first-generation β-lactamase inhibitors (clavulanic acid, sulbactam and tazobactam) are all β-lactam derivatives and work primarily by inactivating class A and some class C serine β-lactamases. The newer generations of β-lactamase inhibitors including avibactam and vaborbactam are based on non-β-lactam structures and their spectrum of inhibition is extended to KPC as an important class A carbapenemase. Despite these advances several class D and virtually all important class B β-lactamases are resistant to existing inhibitors. The present review provides an overview of recent FDA-approved β-lactam/β-lactamase inhibitor combinations as well as an update on research efforts aimed at the discovery and development of novel β-lactamase inhibitors.

Gut Colonization with Carbapenem-resistant Enterobacteriaceae Adversely Impacts the Outcome in Patients with Hematological Malignancies: Results of A Prospective Surveillance Study

BACKGROUND

Gut colonisation with carbapenem-resistant enterobacteriaceae (CRE) is a risk factor for CRE bacteremia and patients with haematological malignancies (HM) are at the highest risk of mortality.

METHODS

We conducted a prospective surveillance study of gut colonisation with CRE and its impact on the outcome of 225 consecutive patients of HM over 28 months.

RESULTS

The median age of the cohort was 46 years, the majority with acute leukaemia. 48 (21%) patients were colonised with CRE on admission (CAD). Another 46 patients were colonised with CRE in the hospital (CIH). The risk factors for CAD and CIH were a diagnosis of acute leukaemia and duration of hospital stay respectively. CRE accounted for 77% of infection-related mortality (IRM). The incidence of CRE bacteremia in CRE positive patients was 18% (17/94), and mortality in those with CRE bacteremia was 100%. IRM was 35.3% in CIH group compared to 10.5% in the CAD group (p=0.0001). IRM was highest in those with acute myeloid leukaemia (AML) and CIH (54.9% p=0.0001). On multivariate analysis, CIH was the most important risk factor for IRM (HR-7.2).

CONCLUSION

Our data demonstrate that a substantial proportion of patients with HM are colonised with CRE without prior hospitalisation, but those with nosocomial colonisation have the highest risk of mortality, particularly in those with AML.