Efficacy of ceftazidime-avibactam in solid organ transplant recipients with bloodstream infections caused by carbapenemase-producing Klebsiella pneumoniae

Whole-genome sequencing characterisation of a new KPC-245 variant-carrying Klebsiella pneumoniae strain isolated from a transplanted patient and resistant to ceftazidime/avibactam, meropenem/vaborbactam and imipenem/relebactam

OBJECTIVE

In recent decades, the increasing prevalence of multidrug-resistant Klebsiella pneumoniae carbapenemase (KPC)-carrying K. pneumoniae (KPC-Kp) has become a worldwide public concern. Herein, we characterised a ceftazidime/avibactam (CAZ/AVI), meropenem/vaborbactam (MER/VAB) and imipenem/relebactam (IMI/REL)-resistant KPC-Kp strain isolated from a critically ill transplant patient.

METHODS

Antimicrobial susceptibility testing and whole-genome sequencing (WGS) were conducted to characterise the strain at phenotypic and genotypic levels. Genomic DNA was sequenced using the Illumina platform. Bioinformatic analyses were used to investigate the genome sequences both for resistance and virulence features, and for the characterisation of plasmids.

RESULTS

Phenotypic characterisation revealed that the KPC-Kp isolate was highly resistant to a wide range of antibiotics, including all β-lactam/β-lactamase inhibitor combinations such as CAZ/AVI, MER/VAB, IMI/REL and cefiderocol. WGS analysis showed that the isolate, belonging to the rare lineage ST661, contained several resistance and virulence genes. Among the resistance genes, we identified a new KPC variant within the mobile genetic element Tn4401-KPC-245-characterised by the insertion of nine amino acids (RAPNKDDYT) at position 263 as well as an amino acid change within the protein sequence, E274D, compared with KPC-3. Interestingly, the presence of mutations only in the blaKPC gene and not in other β-lactamase coding genes strongly points to the role of KPC-245 in β-lactam/β-lactamase inhibitor combinations and cefiderocol resistance.

CONCLUSIONS

In our study, by using WGS analysis on a clinical isolate, we identified a new blaKPC variant within the Tn4401 transposon. Our results confirm the importance of continuous surveillance of multidrug-resistant K. pneumoniae in the clinical context.

Infections Management in the Lung Transplant Setting in Italy: A Web-Survey

INTRODUCTION

Infections significantly impact morbidity and mortality in lung transplant (LuTx) recipients. This survey focused on documenting current practices regarding the prevention and management of infections in LuTx in Italy.

METHODS

A 52-question survey was administered online in the period from December 1, 2023, to January 31, 2024, assessing center characteristics, Tx team organization, microbiological investigations, infection prevention, and management. All Italian LuTx centers were invited to participate.

RESULTS

Nine out of 10 Italian LuTx centers answered. Most centers (6/9, 67%) performed LuTx only on adults. Chronic infection or colonization by Mycobacterium abscessus and Burkholderia cenocepacia is considered a contraindication to LuTx in five and two centers, respectively. For cytomegalovirus D+/R- patients, prophylaxis is used in six centers (67%), with a variable duration from 3 to 12 months. Two centers also use IgG. Three centers (33%) use a pre-emptive strategy. Four centers (45%) screen for Human herpesvirus 8 infection. Regarding antibiotic prophylaxis, most centers (6/9, 67%) utilise a dual regimen of anti-pseudomonal penicillin plus glycopeptide. The two most common durations of antibiotic prophylaxis were 72 h and 7 days, each reported by two centers (22%). Targeted prophylaxis against fungal infections is employed by a minority of centers (4/9, 44%). Inhaled amphotericin B is the most common antifungal, used as targeted prophylaxis (2/4, 50%) and universal prophylaxis (2/5, 40%). Almost all centers (8/9, 89%) involve the Tx infectious diseases specialist in the recipient management since the pre-listing period.

CONCLUSION

There is considerable heterogeneity in infection management among Italian LuTx centers. Establishing a shared platform for data collection and outcome evaluation is essential to improve infection management.

Clinical impact of ceftazidime/avibactam on the treatment of suspected or proven infections in a large cohort of patients with haematological malignancies: a multicentre observational real-world study

OBJECTIVES

To evaluate clinical impact of ceftazidime/avibactam on treating infections due to MDR Gram-negative bacteria in patients with haematological malignancies (HMs).

METHODS

We conducted a retrospective, observational study at 17 Italian haematological wards that included patients with HMs receiving ceftazidime/avibactam for the treatment of suspected or proven infections. The primary endpoint was all-cause mortality 30 days after infection onset. Secondary endpoints included the development of in vitro ceftazidime/avibactam resistance, adverse reactions and infection relapse.

RESULTS

Of 198 patients enrolled, 66 had fever of unknown origin and 132 had microbiologically proven infections (MPIs). Enterobacterales were responsible for 98 MPIs, with KPC producers accounting for 75% of these, and carbapenem-resistant Pseudomonas aeruginosa caused 25% of MPIs. The overall 30-day mortality rate was 17.7%. Infection relapse occurred in four patients with MPI. Patients who died within 30 days of infection onset tended to have pre-existing cerebrovascular diseases, a Charlson Comorbidity Index > 4 and septic shock at infection onset and had received inadequate initial antibiotic therapy. Thirty-day mortality was independently associated with septic shock at infection onset and inappropriate initial antibiotic therapy.

CONCLUSIONS

Our study provides further evidence about the effectiveness of ceftazidime/avibactam in treating infections in patients with HMs.

Cardoso F, P. Marques H. Carbapenem-Resistant Enterobacteriaceae Colonization or Infection Was Not Associated with Post-Liver Transplant Graft Failure: An Observational Cohort Study

Introduction

Carbapenem-resistant Enterobacteriaceae (CRE) epidemiology among liver transplant (LT) recipients is variable. We studied the impact of CRE colonization and infection on LT recipients' outcomes.

Methods

This observational cohort study included consecutive adult LT recipients between January 2019 and December 2020 at Curry Cabral Hospital, Lisbon, Portugal. Primary exposures were CRE colonization (rectal swabs under a screening program) and infection within 1 year of index LT. Primary endpoint was graft failure within 1 year of the index LT.

Results

Among 209 patients, the median (interquartile range [IQR]) age was 57 (47-64) years and 155 (74.2%) were male. CRE colonization was identified in 28 (13.4%) patients during the first year posttransplant (median [IQR] number of rectal swabs per patient of 4 [2-7]). CRE resistance genes identified were OXA48 in 8 (3.6%) patients, KPC in 19 (67.9%) patients, and VIM in 1 (3.6%) patient. Any bacterial/fungal and CRE infections were diagnosed in 88 (42.1%) and 6 (2.9%) patients, respectively, during the first year posttransplant. After adjusting for confounders, neither CRE colonization (aOR [95% CI] = 1.83 [0.71-4.70]; p = 0.21) nor infection (aOR [95% CI] = 1.35 [0.17-11.06]; p = 0.78) was associated with graft failure within 1 year of index LT.

Discussion/Conclusion

Under a screening program, CRE colonization and infection prevalence was low and neither was associated with graft failure.

Ceftazidime-avibactam combination therapy versus monotherapy for treating carbapenem-resistant gram-negative infection: a systemic review and meta-analysis

BACKGROUND

This meta-analysis was conducted to compare the efficacy of ceftazidime-avibactam combination therapy with that of monotherapy in the treatment of carbapenem-resistant Gram-negative bacterial (CR-GNB).

METHODS

A literature search of PubMed, Embase, the Cochrane Library, and ClinicalTrials.gov was conducted until September 1, 2023. Only studies that compared CZA combination therapy with monotherapy for CR-GNB infections were included.

RESULTS

A total of 25 studies (23 retrospective observational studies and 2 prospective studies) involving 2676 patients were included. There was no significant difference in 30-day mortality between the study group receiving combination therapy and the control group receiving monotherapy (risk ratio [RR] 0.91; 95% confidence interval [CI] 0.71-1.18). In addition, no significant differences were observed between the study and the control group in terms of in-hospital mortality (RR 1.00; 95% CI 0.79-1.27), 14-day mortality (RR 1.54; 95% CI 0.24-9.91), 90-day mortality (RR 1.18; 95% CI 0.62-2.22), and clinical cure rate (RR 0.95; 95% CI 0.84-1.08). However, the combination group had a borderline higher microbiological eradication rate than the control group (RR 1.15; 95% CI 1.00-1.32).

CONCLUSIONS

Compared to monotherapy, CZA combination therapy did not yield additional clinical benefits. However, combination therapy may be associated with favorable microbiological outcomes.

Burden and Management of Multi-Drug Resistant Organism Infections in Solid Organ Transplant Recipients Across the World: A Narrative Review

Solid organ transplant (SOT) recipients are particularly susceptible to infections caused by multidrug-resistant organisms (MDRO) and are often the first to be affected by an emerging resistant pathogen. Unfortunately, their prevalence and impact on morbidity and mortality according to the type of graft is not systematically reported from high-as well as from low and middle-income countries (HIC and LMIC). Thus, epidemiology on MDRO in SOT recipients could be subjected to reporting bias. In addition, screening practices and diagnostic resources may vary between countries, as well as the availability of new drugs. In this review, we aimed to depict the burden of main Gram-negative MDRO in SOT patients across HIC and LMIC and to provide an overview of current diagnostic and therapeutic resources.

Donor-derived carbapenem-resistant gram-negative bacterial infections in solid organ transplant recipients: Active surveillance enhances recipient safety

Donor-derived infections (DDIs) caused by carbapenem-resistant gram-negative bacteria (CR-GNB) in solid organ transplant recipients are potentially life-threatening. In this prospective study, we evaluated the incidence, factors associated with transmission, and the outcome of recipients with unexpected CR-GNB DDIs after the implementation of our local active surveillance system (LASS). LASS provides for early detection of unexpected donor CR-GNB infections, prophylaxis of recipients at high risk, and early diagnosis and treatment of DDIs. Whole genome sequencing confirmed DDI. Among 791 recipients, 38 (4.8%) were at high risk of unexpected CR-GNB DDI: 25 for carbapenem-resistant Enterobacterales (CRE) and 13 for carbapenem-resistant Acinetobacter baumannii (CRAB). Transmission did not occur in 27 (71%) cases, whereas DDIs occurred in 9 of 25 of CRE and 2 of 13 of CRAB cases. Incidence of CR-GNB DDI was 1.4%. Recipients of organs with CR-GNB-positive preservation fluid and liver recipients from a donor with CRE infection were at the highest risk of DDI. There was no difference in length of hospital stay or survival in patients with and without CR-GNB DDI. Our LASS contains transmission and mitigates the negative impacts of CR-GNB DDI. Under well-defined conditions, organs from donors with CR-GNB may be considered after a thorough evaluation of the risk/benefit profile.

Clinical outcomes and risk factors for mortality in recipients with carbapenem-resistant gram-negative bacilli infections after kidney transplantation treated with ceftazidime-avibactam: a retrospective study

Background

Ceftazidime-avibactam is a treatment option for carbapenem-resistant gram-negative bacilli (CR-GNB) infections. However, the risk factors associated with ceftazidime-avibactam (CAZ-AVI) treatment failure in kidney transplant (KT) recipients and the need for CAZ-AVI-based combination therapy remain unclear.

Methods

From June 2019 to December 2023, a retrospective observational study of KT recipients with CR-GNB infection treated with CAZ-AVI was conducted, with the primary outcome being 30-day mortality and secondary outcomes being clinical cure, microbiological cure, and safety. Risk factors for 30-day mortality and clinical failure were also investigated.

Results

A total of 81 KT recipients treated with CAZ-AVI were included in this study. Forty recipients (49.4%) received CAZ-AVI monotherapy, with a 30-day mortality of 22.2%. The clinical cure and microbiological cure rates of CAZ/AVI therapy were 72.8% and 66.7%, respectively. CAZ-AVI alone or in combination with other medications had no effect on clinical cure or 30-day mortality. Multivariate logistic regression analysis revealed that a higher Acute Physiology and Chronic Health Evaluation (APACHE) II score (odds ratio [OR]: 4.517; 95% confidence interval [CI]: 1.397-14.607; P = 0.012) was an independent risk factor for 30-day mortality. Clinical cure was positively associated with the administration of CAZ-AVI within 48 hours of infection onset (OR: 11.009; 95% CI: 1.344-90.197; P=0.025) and negatively associated with higher APACHE II scores (OR: 0.700; 95% CI: 0.555-0.882; P=0.002). Four (4.9%) recipients experienced recurrence within 90 days after the initial infection, 3 (3.7%) recipients experienced CAZ-AVI-related adverse events, and no CAZ-AVI resistance was identified.

Conclusion

CAZ-AVI is an effective medication for treating CR-GNB infections following kidney transplantation, even as monotherapy. Optimization of CAZ/AVI therapy (used within 48 hours of infection onset) is positively associated with potential clinical benefit. Further larger-scale studies are needed to validate these findings.

Efficacy of ceftazidime-avibactam in the treatment of carbapenem-resistant Klebsiella pneumoniae infections: Focus on solid organ transplantation recipients

INTRODUCTION

Ceftazidime-avibactam (CAZ-AVI) is a new option to treat KPC- and OXA-48 carbapenem-resistant Klebsiella pneumoniae (CRKP) infections. However, clinical evidence is limited regarding its use in treating CRKP infections, especially in solid organ transplantation (SOT) recipients. In this study, we assessed the efficacy of CAZ-AVI in treating CRKP infections in both the general population and the SOT recipients in comparison with other antibiotic regimens.

METHODS

This is a single-centre retrospective cohort study of patients admitted between January 1, 2018 and June 30, 2021 with the diagnosis of CRKP infections receiving either CAZ-AVI or other regimens ≥ 72 hours and clinical outcomes were analysed.

RESULTS

Of 200 patients with CRKP infections, 67 received CAZ-AVI, 133 received other regimens, and 50 were SOT recipients. In the SOT cohort, 30 patients received CAZ-AVI, and 20 received other regimens. The overall 30-day mortality was 38% in the SOT cohort. Compared with patients receiving other regimens, CAZ-AVI therapy resulted in lower 30-day mortality (23.3% vs. 60%, P = 0.014) and 90-day mortality (35.7% vs. 86.7%, P = 0.003), higher clinical cure (93.3% vs. 40%, P < 0.001) and microbiological clearance. Similar promising results of CAZ-AVI were also shown in the whole population cohort. Moreover, clinical outcomes of SOT recipients receiving CAZ-AVI were not inferior to those without SOT.

CONCLUSIONS

CAZ-AVI therapy was associated with better clinical outcomes in CRKP infections in both the general population and SOT recipients. Considering the limitations of the present study, well-conducted RCTs are still warranted to confirm these findings.

New Antibiotics Against Multidrug-Resistant Gram-Negative Bacteria in Liver Transplantation: Clinical Perspectives, Toxicity, and PK/PD Properties

Antimicrobial resistance is a growing global health problem, and it is especially relevant among liver transplant recipients where infections, particularly when caused by microorganisms with a difficult-to-treat profile, are a significant cause of morbidity and mortality. We provide here a complete dissection of the antibiotics active against multidrug-resistant Gram-negative bacteria approved over the last years, focusing on their activity spectrum, toxicity profile and PK/PD properties, including therapeutic drug monitoring, in the setting of liver transplantation. Specifically, the following drugs are presented: ceftolozane/tazobactam, ceftazidime/avibactam, meropenem/vaborbactam, imipenem/relebactam, cefiderocol, and eravacycline. Overall, studies on the safety and optimal employment of these drugs in liver transplant recipients are limited and especially needed. Nevertheless, these pharmaceuticals have undeniably enhanced therapeutic options for infected liver transplant recipients.

Early Intra-Abdominal Bacterial Infections after Orthotopic Liver Transplantation: A Narrative Review for Clinicians

Despite recent advances in the transplant field, infectious complications after orthotopic liver transplantation (OLT) are major causes of morbidity and mortality. Bacterial intra-abdominal infections (IAIs) are predominant during the first month post-transplantation and affect patient and graft survival. Recently, the emergence of multidrug resistant bacteria has generated great concern in OLT patients. We performed this narrative review of the literature in order to propose a "ready-to-use" flowchart for reasoned empirical antibiotic therapy in the case of suspected post-OLT IAIs. The review was ultimately organized into four sections: "Epidemiology and predisposing factors for IAI"; "Surgical-site infections and perioperative prophylaxis"; "MDRO colonization and infections"; and "Reasoned-empirical antibiotic therapy in early intra-abdominal infections post OLT and source control". Multidisciplinary teamwork is warranted to individualize strategies for the prevention and treatment of IAIs in OLT recipients, taking into account each patient's risk factors, the surgical characteristics, and the local bacterial epidemiology.