Incidence of colonization and bloodstream infection with carbapenem-resistant Enterobacteriaceae in children receiving antineoplastic chemotherapy in Italy

Benefits and Safety of Empiric Antibiotic Treatment Active Against KPC-Producing Klebsiella pneumoniae for Febrile Neutropenic Episodes in Colonized Children with Acute Leukemia-An 8-Year Retrospective Observational Study

In children with acute leukemia (AL), the mortality rate from Klebsiella pneumoniae carbapenemase (KPC)-producing K. pneumoniae bloodstream infection (KPC-KpBSI) exceeds 50%, highest when active treatment is delayed. Neutropenic KPC-K. pneumoniae carriers are at high risk of KPC-KpBSI, and preemptive empiric antibiotic treatment (EAT) of febrile neutropenic episodes (FNEs) active against KPC-K. pneumoniae may reduce this mortality. We conducted an 8-year (2014-2021) retrospective observational study of 112 febrile neutropenic episodes (FNEs) in 32 children with AL who were KPC-K. pneumoniae carriers: standard EAT for 39 FNEs and active EAT for 73 FNEs (52 ceftazidime/avibactam (CAZAVI)-based and 21 colistin-based combinations, and 5 CAZAVI monotherapy). Successful outcomes (survival from FNE) were observed in 94%; seven were fatal, with four due to infectious causes. KPC-KpBSIs caused 10/112 FNEs, 10/20 g-negative BSIs, and 3 deaths. The mortality rate of KPC-KpBSI was 30%. Active EAT was successful in 97% of the FNEs, compared to 87% with standard EAT. All deaths from KPC-KpBSI occurred in patients who received standard EAT, while none occurred with active EAT. KPC-KpBSI mortality rate with initial inactive treatment was 60%. CAZAVI-based EAT was successful in all FNEs, with a higher success rate without any modification compared to colistin-based EAT, where nephrotoxicity occurred in 14%. Therefore, active EAT, mainly a CAZAVI-based combination, was effective, safe, and associated with low overall and KPC-KpBSI-related mortality.

Use of Ceftazidime-Avibactam for Suspected or Confirmed Carbapenem-Resistant Organisms in Children: A Retrospective Study

Background

The incidence of carbapenem-resistant organism (CRO) infections is increasing in children. However, pediatric-specific treatment strategies present unique challenges. Ceftazidime/avibactam is a β-lactam/β-lactamase inhibitor combination, showing adequate efficiency against CRO isolates. However, clinical data on the efficacy of ceftazidime/avibactam in children are still lacking.

Methods

This was a retrospective study of children (aged <18 years) infected with confirmed or suspected carbapenem-resistant pathogens and treated with ceftazidime-avibactam at the First Affiliated Hospital of Zhengzhou University between 2020 and 2022.

Results

We identified 38 children aged 14 (5.0-16.3) years; 20 (52.6%) had hematologic malignancies. 25 children with confirmed CRO infections were administered ceftazidime-avibactam as targeted therapy. The median treatment was 10 (6.0-16.5) days. Among them, 24 had infections caused by carbapenem-resistant Enterobacterales (CRE) (18 carbapenem-resistant Klebsiella pneumoniae and six carbapenem-resistant Escherichia coli species) and one with carbapenem-resistant Pseudomonas aeruginosa strains. The source of infection was the bloodstream in 60.0% of the cases (15/25). The clinical response rate was 84.0% (21/25), and 30-day mortality rate was 20% (5/25). 13 children were administered ceftazidime-avibactam as empiric therapy for suspected infections. The median treatment was 8 (6.0-13.0) days. No deaths occurred and clinical response was achieved in 12 of the 13 patients (92.3%) who empirically treated with ceftazidime-avibactam.

Conclusion

Ceftazidime-avibactam is important for improving survival, and clinical response in children with infections caused by CRO.

Antibiotic resistance in bloodstream isolates from high-complexity paediatric units in Madrid, Spain: 2013-2021

BACKGROUND

Antimicrobial resistance (AMR) has become a significant challenge in high-complexity healthcare settings.

AIM

To evaluate the prevalence of AMR in bloodstream isolates from high-complexity paediatric units in Spain over a nine-year period.

METHODS

A retrospective observational multicentre study was conducted in three tertiary hospitals, analysing bloodstream isolates from patients aged <18 years admitted to the paediatric intensive care, neonatology, and oncology-haematology units between 2013 and 2021. Demographics, antimicrobial susceptibility, and resistance mechanisms were analysed in two periods (2013-2017 and 2017-2021).

FINDINGS

In all, 1255 isolates were included. AMR was more prevalent in older patients and those admitted to the oncology-haematology unit. Multidrug resistance was observed in 9.9% of Gram-negative bacteria (GNB); 20.0% of P. aeruginosa vs 8.6% of Entero-bacterales (P < 0.001), with an increase in Enterobacterales from 6.2% to 11.0% between the first and the second period (P = 0.021). Difficult-to-treat resistance was observed in 2.7% of GNB; 7.4% of P. aeruginosa vs 1.6% of Enterobacterales (P < 0.001), with an increasing trend in Enterobacterales from 0.8% to 2.5% (P = 0.076). Carbapenem resistance among Enterobacterales increased from 3.5% to 7.2% (P = 0.029), with 3.3% producing carbapenemases (67.9% VIM). Meticillin resistance was observed in 11.0% of S. aureus and vancomycin resistance in 1.4% of Enterococcus spp., with both rates remaining stable throughout the study period.

CONCLUSION

This study reveals a high prevalence of AMR in high-complexity paediatric units. Enterobacterales showed a concerning increasing trend in resistant strains, with higher rates among older patients and those admitted to oncology-haematology units.

Novel Beta Lactam Antibiotics for the Treatment of Multidrug-Resistant Gram-Negative Infections in Children: A Narrative Review

Infections due to carbapenem-resistant Enterobacterales (CRE) are increasingly prevalent in children and are associated with poor clinical outcomes, especially in critically ill patients. Novel beta lactam antibiotics, including ceftolozane-tazobactam, ceftazidime-avibactam, meropenem-vaborbactam, imipenem-cilastatin-relebactam, and cefiderocol, have been released in recent years to face the emerging challenge of multidrug-resistant (MDR) Gram-negative bacteria. Nonetheless, several novel agents lack pediatric indications approved by the Food and Drug Administration (FDA) and the European Medicine Agency (EMA), leading to uncertain pediatric-specific treatment strategies and uncertain dosing regimens in the pediatric population. In this narrative review we have summarized the available clinical and pharmacological data, current limitations and future prospects of novel beta lactam antibiotics in the pediatric population.

A Protocol for Low-Input RNA-Sequencing of Patients with Febrile Neutropenia Captures Relevant Immunological Information

Improved methods are needed for diagnosing infectious diseases in children with cancer. Most children have fever for other reasons than bacterial infection and are exposed to unnecessary antibiotics and hospital admission. Recent research has shown that host whole blood RNA transcriptomic signatures can distinguish bacterial infection from other causes of fever. Implementation of this method in clinics could change the diagnostic approach for children with cancer and suspected infection. However, extracting sufficient mRNA to perform transcriptome profiling by standard methods is challenging due to the patient's low white blood cell (WBC) counts. In this prospective cohort study, we succeeded in sequencing 95% of samples from children with leukaemia and suspected infection by using a low-input protocol. This could be a solution to the issue of obtaining sufficient RNA for sequencing from patients with low white blood cell counts. Further studies are required to determine whether the captured immune gene signatures are clinically valid and thus useful to clinicians as a diagnostic tool for patients with cancer and suspected infection.

Consensus document on the management of febrile neutropenia in paediatric haematology and oncology patients of the Spanish Society of Pediatric Infectious Diseases (SEIP) and the Spanish Society of Pediatric Hematology and Oncology (SEHOP)

Febrile neutropenia is one of the main infectious complications experienced by paediatric patients with blood or solid tumours, which, despite the advances in diagnosis and treatment, are still associated with a significant morbidity and mortality. These patients have several risk factors for infection, chief of which are chemotherapy-induced neutropenia, the disruption of cutaneous and mucosal barriers and the use of intravascular devices. Early diagnosis and treatment of febrile neutropenia episodes based on the patient's characteristics is essential in patients with blood and solid tumours to improve their outcomes. Therefore, it is important to develop protocols in order to optimise and standardise its management. In addition, the rational use of antibiotics, with careful adjustment of the duration of treatment and antimicrobial spectrum, is crucial to address the increase in antimicrobial drug resistance. The aim of this document, developed jointly by the Spanish Society of Pediatric Infectious Diseases and the Spanish Society of Pediatric Hematology and Oncology, is to provide consensus recommendations for the management of febrile neutropenia in paediatric oncology and haematology patients, including the initial evaluation, the stepwise approach to its treatment, supportive care and invasive fungal infection, which each facility then needs to adapt to the characteristics of its patients and local epidemiological trends.

Klebsiella pneumoniae Carbapenemase Variants Resistant to Ceftazidime-Avibactam: an Evolutionary Overview

First variants of the Klebsiella pneumoniae carbapenemase (KPC), KPC-2 and KPC-3, have encountered a worldwide success, particularly in K. pneumoniae isolates. These beta-lactamases conferred resistance to most beta-lactams including carbapenems but remained susceptible to new beta-lactam/beta-lactamase inhibitors, such as ceftazidime-avibactam. After the marketing of ceftazidime-avibactam, numerous variants of KPC resistant to this association have been described among isolates recovered from clinical samples or derived from experimental studies. In KPC variants resistant to ceftazidime-avibactam, point mutations, insertions and/or deletions have been described in various hot spots. Deciphering the impact of these mutations is crucial, not only from a therapeutic point of view, but also to follow the evolution in time and space of KPC variants resistant to ceftazidime-avibactam. In this review, we describe the mutational landscape of the KPC beta-lactamase toward ceftazidime-avibactam resistance based on a multidisciplinary approach including epidemiology, microbiology, enzymology, and thermodynamics. We show that resistance is associated with three hot spots, with a high representation of insertions and deletions compared with other class A beta-lactamases. Moreover, extension of resistance to ceftazidime-avibactam is associated with a trade-off in the resistance to other beta-lactams and a decrease in enzyme stability. Nevertheless, the high natural stability of KPC could underlay the propensity of this enzyme to acquire in vivo mutations conferring resistance to ceftazidime-avibactam (CAZavi), particularly via insertions and deletions.

Carbapenem-resistant Enterobacteriaceae bloodstream infections: A case-control study from a pediatric referral hospital in Argentina

Background

Antibiotic-resistant gram-negative bloodstream infections (BSI) remain a leading cause morbidity and mortality in pediatric patients with a high impact on the public health system. Data in resource-limited countries, including those in Latin America and the Caribbean region, are scarce. The aim of the study was to identify risk factors for acquiring carbapenem-resistant Enterobacteriaceae (CRE) bacteremia in children and to assess the use of resources.

Methods

A retrospective case-control study was conducted to analyze demographic, epidemiological, clinical, microbiological, and outcome data as well as the use of resources between 2014 and 2019. Univariate and logistic regression analysis was performed in order to identify risk factors associated with CRE-BSI. The R software version 4.1.2 was used.

Results

A total of 46 cases with CRE-BSI and 92 controls with gram-negative non-CRE-BSI were included. No statistical difference was observed regarding: median age (36 months; IQR, 11.2-117 vs. 48 months, IQR 13-119), male sex (50 vs. 60%), and underlying disease (98 vs. 91%) in cases vs. controls, respectively. The most frequent mechanism of CRE bacteremia were: KPC in 74%, OXA in 15%, and NDM in 6.5%. A total of 54.3% of cases vs. 32.6 % (p = 0.016) of controls were admitted to the pediatric intensive care unit (PICU), and 48 vs. 21% (p = 0.001) required mechanical ventilation. Bacteremia secondary to intra-abdominal infection was observed in 56.5% of cases vs. 35% of controls (p = 0.032). Previous colonization with CRE was detected in 76% of cases vs. 8% of controls. Combination antimicrobial treatment was most frequent in cases vs. control (100 vs. 56.5%). No difference was observed in median length of hospital stay (22 days; IQR, 19-31 in cases vs. 17.5 days; IQR, 10-31 in controls; p = 0.8). Overall case fatality ratio was 13 vs. 5.5%, respectively. The most statistically significant risk factors included previous PICU stay (OR, 4; 95%CI, 2-8), invasive procedures/surgery (OR, 3; 95%CI, 1-7), central venous catheter placement (OR, 6.5; 95%CI, 2-19), urinary catheter placement (OR, 9; 95%CI 4-20), mechanical ventilation (OR, 4; 95%CI, 2-10), liver transplantation (OR, 8; 95%CI, 2-26), meropenem treatment (OR, 8.4; 3.5-22.6) in univariate analysis. The logistic regression model used for multivariate analysis yielded significant differences for previous meropenem treatment (OR, 13; 95%CI, 3-77; p = 0.001), liver transplantation (OR, 13; 95%CI, 2.5-100; p = 0.006), and urinary catheter placement (OR, 9; 95%CI, 1.4-94; p = 0.03).

Conclusion

CRE-BSI affects hospitalized children with underlying disease, mainly after liver transplantation, with previous urinary catheter use and receiving broad-spectrum antibiotics, leading to high PICU requirement and mortality. These risk factors will have to be taken into account in our region in order to establish adequate health policies and programs to improve antimicrobial stewardship.

Risk factors for antibiotic-resistant bacteria colonisation in children with chronic complex conditions

To assess drug-resistant bacterial colonisation rates and associated risk factors in children with complex chronic conditions admitted to a national reference unit in Spain. Cross-sectional study that included all children admitted to our unit from September 2018 to July 2019. Rectal swabs were obtained to determine multidrug-resistant Gram-negative bacilli (MR-GNB) colonisation, and nasal swab to determine S. aureus and methicillin-resistant S. aureus (MRSA) colonisation. Medical records were reviewed. 100 children were included, with a median of four complex chronic conditions. Sixteen percent had S. aureus colonisation, including two MRSA. S. aureus colonisation was associated with technology-dependent children, while being on antibiotic prophylaxis or having undergone antibiotic therapy in the previous month were protective factors. The prevalence of MR-GNB colonisation was 27%, which was associated with immunosuppressive therapy (aOR 31; 2.02–47]; p = 0.01), antibiotic prophylaxis (aOR 4.56; 1.4–14.86; p = 0.012), previously treated skin-infections (aOR 2.9; 1.07–8.14; p = 0.03), surgery in the previous year (aOR 1.4; 1.06–1.8; p = 0.014), and hospital admission in the previous year (aOR 1.79; [1.26–2.56]; p = 0.001). The rate of S. aureus nasal colonisation in this series was not high despite the presence of chronic conditions, and few cases corresponded to MRSA. Antibiotic prophylaxis, immunosuppressive therapies, history of infections, previous surgeries, and length of admission in the previous year were risk factors for MR-GNB colonisation.

8th European Conference on Infections in Leukaemia: 2020 guidelines for the use of antibiotics in paediatric patients with cancer or post-haematopoietic cell transplantation

Paediatric patients with cancer and those undergoing haematopoietic cell transplantation are at high risk of bacterial infections. The 8th European Conference on Infections in Leukaemia (ECIL-8) convened a Paediatric Group to review the literature and to formulate recommendations for the use of antibiotics according to the European Society of Clinical Microbiology and Infectious Diseases grading system. The evaluation of antibacterial prophylaxis included mortality, bloodstream infection, febrile neutropenia, emergence of resistance, and adverse effects as endpoints. Initial antibacterial therapy and antibiotic de-escalation or discontinuation focused on patients with a clinically stable condition and without previous infection or colonisation by resistant bacteria, and on patients with a clinically unstable condition or with previous infection or colonisation by resistant bacteria. The final considerations and recommendations of the ECIL-8 Paediatric Group on antibacterial prophylaxis, initial therapy, and de-escalation strategies are summarised in this Policy Review.

The gut microbiome in pediatric patients undergoing allogeneic hematopoietic stem cell transplantation

The gut microbiome (GM) has been associated with different clinical outcomes in the context of allogeneic hematopoietic stem cell transplantation (HSCT). Large multicenter cohort studies in adults have found significant correlations with overall survival, relapse, and incidence of complications. Moreover, GM is already a promising target for therapeutic interventions. However, few data are available in children, a population presenting unique features and challenges. During childhood, the GM evolves rapidly with large structural fluctuations, alongside with the maturation of the immune system. Furthermore, the HSCT procedure presents significant differences in children. These considerations underline the importance of a specific focus on the pediatric setting, and the role of GM and its age-dependent trajectory in influencing the immunity reconstitution and clinical outcomes. This review provides a comprehensive overview of the available evidence in the field of GM and pediatric HSCT, highlighting age-specific issues and discussing GM-based therapeutic approaches.

Colonisation with extended spectrum beta-lactamase-producing and carbapenem-resistant Enterobacterales in children admitted to a paediatric referral hospital in South Africa

INTRODUCTION

There are few studies describing colonisation with extended spectrum beta-lactamase-producing Enterobacterales (ESBL-PE) and carbapenem-resistant Enterobacterales (CRE) among children in sub-Saharan Africa. Colonisation often precedes infection and multi-drug-resistant Enterobacterales are important causes of invasive infection.

METHODS

In this prospective cross-sectional study, conducted between April and June 2017, 200 children in a tertiary academic hospital were screened by rectal swab for EBSL-PE and CRE. The resistance-conferring genes were identified using polymerase chain reaction technology. Risk factors for colonisation were also evaluated.

RESULTS

Overall, 48% (96/200) of the children were colonised with at least one ESBL-PE, 8.3% (8/96) of these with 2 ESBL-PE, and one other child was colonised with a CRE (0.5% (1/200)). Common colonising ESBL-PE were Klebsiella pneumoniae (62.5%, 65/104) and Escherichia coli (34.6%, 36/104). The most frequent ESBL-conferring gene was blaCTX-M in 95% (76/80) of the isolates. No resistance- conferring gene was identified in the CRE isolate (Enterobacter cloacae). Most of the Klebsiella pneumoniae isolates were susceptible to piperacillin/tazobactam (86.2%) and amikacin (63.9%). Similarly, 94.4% and 97.2% of the Escherichia coli isolates were susceptible to piperacillin/tazobactam and amikacin, respectively. Hospitalisation for more than 7 days before study enrolment was associated with ESBL-PE colonisation.

CONCLUSION

Approximately half of the hospitalised children in this study were colonised with ESBL-PE. This highlights the need for improved infection prevention and control practices to limit the dissemination of these microorganisms.

Epidemiology and Risk Factors Associated With Mortality in Consecutive Patients With Bacterial Bloodstream Infection: Impact of MDR and XDR Bacteria

Background

 Mortality related to bloodstream infections (BSIs) is high. The epidemiology of BSIs is changing due to the increase in multidrug resistance, and it is unclear whether the presence of multidrug-resistant (MDR) organisms, per se, is an independent risk factor for mortality. Our objectives were, first, to describe the epidemiology and outcome of BSIs and, second, to determine the risk factors associated with mortality among patients with BSI.

Methods

 This research used a single-center retrospective observational study design. Patients were identified through microbiological reports. Data on medical history, clinical condition, bacteria, antimicrobial therapy, and mortality were collected. The primary outcome was crude mortality at 30 days. The relationships between mortality and demographic, clinical, and microbiological variables were analyzed by multivariate analysis.

Results

 A total of 1049 inpatients were included. MDR bacteria were isolated in 27.83% of patients, where 2.14% corresponded to an extremely drug-resistant (XDR) isolate. The crude mortality rates at days 7, 30, and 90 were 12.11%, 25.17%, and 36.13%, respectively. Pitt score >2, lung and abdomen as site of infection, and XDR Pseudomonas aeruginosa were independent risk factors for 7-, 30-, and 90-day mortality. Charlson score >4, carbapenem-resistant Klebsiella pneumoniae, and XDR Acinetobacter baumannii were independent risk factors for 30- and 90-day mortality. Infection by XDR gram-negative bacteria, Charlson score >4, and immunosuppression were independent risk factors for mortality in patients who were stable at the time of BSI.

Conclusions

 BSI is an event with an extreme impact on mortality. Patients with severe clinical condition are at higher risk of death. The presence of XDR gram-negative bacteria in blood is strongly and independently associated with patient death.

Prevalence, Epidemiology, Etiology, and Sensitivity of Invasive Bacterial Infections in Pediatric Patients Undergoing Oncological Treatment: A Multicenter Nationwide Study

Background: Infectious complications (IC) caused by bacterial strains often impede anticancer therapy. The study aimed to retrospectively analyze bacterial IC that could help predict the risk and optimize the empirical treatment for bacterial infections in pediatric cancer patients. Patients and Methods: Over a 72-month period, all-in 5,599 children with cancer: 2,441 patients with hematological malignancy (HM including acute leukemias, Hodgkin and non-Hodgkin lymphomas [NHLs], and Langerhans cell histiocytosis) and 3,158 with solid tumors (STs including central nervous system tumors, neuroblastoma, Wilms' tumor, soft tissue sarcoma, germ cell tumors, Ewing sarcoma, osteosarcoma, hepatoblastoma, and others) were enrolled into the study. Episodes of bacterial infectious complications (EBICs) confirmed by microbiological findings were reported by each hospital and analyzed centrally. Results: At least 1 EBIC was diagnosed in 2,155 (36.8%) children (1,281 [59.4%] with HM and 874 [40.6%] with ST; p < 0.001). All-in 4,860 EBICs were diagnosed including 62.2% episodes in children with HM and 37.8% in children with ST (p < 0.001). Having analyzed the source of infections, blood stream infections predominated, apart from NHL patients in whom the most common type was gut infections. The profile of bacteria strains was different in HM and ST groups (p < 0.001). However, in both groups the most common Gram-negative pathogen was Enterobacteriaceae, with the rate being higher in the HM group. Among Gram-negative strains low susceptibility to ceftazidime, whereas among Enterococcus spp. low susceptibility to vancomycin was noticed. The rate of multidrug-resistant (MDR) pathogens was high, especially for Gram negatives (47.7% vs. 23.9%; p < 0.001). The survival after infections was comparable for HM and ST patients (p = 0.215). Conclusions: The risk of bacterial IC in HM patients was higher than in the ST group. The high rate of MDR strains was detected in pediatric cancer patients, especially in those with HM.

Fecal Carriage of Extended-Spectrum β-Lactamase and Carbapenemase-Producing Enterobacterales Strains in Patients with Colorectal Cancer in the Oncology Unit of Amizour Hospital, Algeria: A Prospective Cohort Study

Background: The prevalence of extended-spectrum β-lactamase (ESBL)-producing Enterobacterales (ESBL-E) and carbapenemase-producing Enterobacterales (CPE) is now disseminated worldwide. This study aims to describe the prevalence of ESBL and CPE fecal carriage in colorectal cancer patients. Methods: All patients admitted to the oncology service of Amizour hospital (Algeria) for colorectal cancer chemotherapy from March to May 2019 were screened for ESBL-E or CPE fecal carriage. After culturing on chromogenic media, the presumptive colonies were identified by mass spectroscopy. Antibiotic susceptibility testing was performed according to the European Committee on Antimicrobial Susceptibility Testing. The β-lactamases encoding genes and plasmid-mediated quinolone-resistant genes were screened by PCR and sequencing. Results: ESBL-E strains were recovered from rectal swabs in 6 patients (14.3%) and only 1 patient (2.4%) was found a carrier for OXA-48-producing Klebsiella pneumoniae. The most frequently encountered species among ESBL-E was Escherichia coli (n = 5), followed by K. pneumoniae (n = 1). PCR and sequencing showed that four isolates harbored the bla_CTX-M-15 gene and two strains harbored the bla_CTX-M-14 gene. Also, one strain of K. pneumoniae was found to harbor both qepA and qnrS genes. Conclusion: This study highlighted the fecal carriage of ESBL-E and OXA-48-producing Enterobacterales strains in colorectal cancer patients.

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.

Gram-negative Bacteremia in Children With Hematologic Malignancies and Following Hematopoietic Stem Cell Transplantation: Epidemiology, Resistance, and Outcome

Gram-negative rod (GNR) infections adversely affect the outcome of patients with malignancies and following hematopoietic stem cell transplantation (HSCT). This retrospective observational study aimed to describe the epidemiology, outcome, and resistance patterns of GNR bacteremia in children with hematologic malignancies (HM) and after HSCT during the period spanning from 2010 to 2014 in a tertiary children's hospital. A total of 270 children were included in the analysis; 65 (24%) developed 85 episodes of GNR bacteremia; the rate was 36/122 (29.5%) in post-HSCT and 29/178 (16.3%) in HM patients (P<0.05). Overall, 10% of the GNRs were carbapenem resistant. In multivariate analysis, prolonged neutropenia (≥7 d; odds ratio: 19.5, 95% confidence interval: 2.6-148.4) and total hospitalization for a duration of >30 days in the last 3 months (odds ratio: 17.5, 95% confidence interval: 1.4-224.4) were associated with carbapenem-resistant GNR bacteremia. Thirty-day mortality following GNR bacteremia was 0% in HM and 7/52 episodes (13.5%) in HSCT patients (P<0.05). Carbapenem-resistant versus carbapenem-sensitive bacteremia was associated with longer duration of bacteremia (mean: 3.8 vs. 1.7 d), higher risk for intensive care unit hospitalization (44.4% vs. 10.1%), and higher mortality rate (33% vs. 5.8%) (P<0.05). To summarize, GNR bacteremia was frequent, especially in post-HSCT children. Carbapenem resistance adversely affects patients' outcome, increasing morbidity and mortality. Empirical antibiotic therapy must be adjusted to the local resistance patterns.

Epidemiology of carbapenemase-producing Enterobacteriaceae in a pediatric hospital in a country with high endemicity

BACKGROUND

Little is known about epidemiology of carbapenemase-producing Enterobacteriaceae (CPE) in children. Aim of this study was to describe CPE epidemiology in a tertiary care pediatric hospital in Italy that admits patients coming from geographic areas with high diffusion of CPE.

METHODS

Prospective evaluation of the proportion and rates per 100,000 hospital discharges (D) or hospitalization-days (HD) of invasive infections due to CPE from 2013 to 2017 and of CPE infections and colonizations from 2014 to 2017. Disease-preventing strategies comprised patients' screening at admission, pre-emptive contact isolation precautions pending cultures results, and bundles for prevention of healthcare associated infections.

RESULTS

From 2013 to 2017 CPE represented 3.5% of all invasive infections due to Enterobacteriaceae, with rates ranging 7.30-14.33 for D and 1.03-2.06 for HD, without major changes over time. On the contrary, overall rates of isolates increased from 83.03 to 191.34 for D and from 12.21 to 28.35 for HD. The intra-hospital diffusion consisted of 2 small outbreaks without invasive diseases in 2014-2015, and sporadic, not epidemiologically-related cases in 2016-2017. Globally, Escherichia coli and Klebsiella pneumoniae represented 64% of identified CPE, while 70% of carbapenemases identified were metallo-beta-lactamases (VIM or NDM), with changes over time.

CONCLUSIONS

In our center metallo-beta lactamases were the most frequently identified carbapenemases in Enterobacteriaceae and E. coli and K. pneumoniae the most frequently isolated pathogens carrying these enzymes. A proactive management strategy was effective in containing in-hospital spreading.

Antibiotic prophylaxis in neutropenic children with acute leukemia: Do the presently available data really support this practice?

Antibiotics are frequently administered for prophylaxis of fever in neutropenic children with cancer. This strategy is mainly derived from adults' data, and various pediatric studies evidenced the effectiveness of antibiotics (eg, fluoroquinolones) in the prevention of febrile neutropenia. However, only two pediatric randomized, double-blind, placebo-controlled trials have been performed, with a total of 262 leukemic children enrolled, and no other one was ever powered for analyzing effectiveness over other infectious complications. In an era of increasing antibiotic resistance, the widespread use of antibiotic prophylaxis in neutropenic leukemic children needs to be strongly supported.

Reducing the impact of carbapenem-resistant Enterobacteriaceae on vulnerable patient groups: what can be done?

PURPOSE OF REVIEW

Carbapenem-resistant Enterobacteriaceae (CRE) is a worldwide challenge and associated with a high mortality rate in critically ill patients. This review focused on rapid diagnosis, optimization of antimicrobial therapy, and implication of effective infection control precautions to reduce impact of CRE on vulnerable patients.

RECENT FINDINGS

Several new diagnostic assays have recently been described for the early diagnosis of CRE. Retrospective studies are supportive for colistin plus meropenem combination for the treatment of CRE infections; however, solid evidence is still lacking. Ceftazidime-avibactam may be an effective therapeutic agent for infections caused by carbapenem-hydrolyzing oxacillinase-48 and Klebsiella pneumoniae carbapenamase-producing Enterobacteriaceae, but not for New Delhi metallo-β-lactamase producers. Gastrointestinal screening may permit early identification of patients with CRE infections. There is not enough evidence to recommend selective digestive decontamination for CRE carriers.

SUMMARY

The information for rapid diagnosis of CRE is accumulating. There are new agents with high in-vitro activity against CRE, but clinical experience is limited to case reports. Active surveillance with a high rate of compliance to basic infection control precautions seems to be the best approach to reduce the impact of CRE on vulnerable patients.

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.

Clinical and Bacterial Risk Factors for Mortality in Children With Carbapenem-resistant Enterobacteriaceae Bloodstream Infections in India

BACKGROUND

Carbapenem-resistant Enterobacteriaceae (CRE) are an increasing cause of nosocomial infection in hospitalized children worldwide. Few studies have investigated risk factors for mortality in children with CRE bloodstream infection (BSI). Data are particularly scarce in areas where NDM and OXA carbapenemases predominate. Here, we investigate mortality rates, clinical and microbiologic risk factors for mortality in 50 pediatric patients with CRE BSI in India.

METHODS

Children younger than 17 years old with meropenem-resistant Klebsiella pneumoniae or Escherichia coli isolated from blood culture in 2014 and 2015 were identified from laboratory records. Clinical records were systematically reviewed for each child to establish mortality at 30 days and clinical details. Bacterial isolates were subjected to meropenem E test and multiplex polymerase chain reaction to determine carbapenemase gene. Data were analyzed to establish clinical and bacterial risk factors for mortality.

RESULTS

All CRE BSI were hospital-acquired or associated with healthcare. A total of 84% of children had an underlying comorbidity and 46% had a malignancy. K. pneumoniae was the most common bacteria isolated; NDM was the most common carbapenemase gene detected. The mortality rate was 52%. Significant risk factors for mortality included intensive care admission, intubation, inotropic support and respiratory source. Failure to clear bacteremia and a minimum inhibitory concentration > 8 mg/L for the isolate was associated with a statistically significant increase in mortality. Mortality rates were significantly lower when two or more effective drugs were used in combination.

CONCLUSIONS

CRE BSI affects children with multiple comorbidities and repeated admissions to hospital. The mortality rate is high; combination therapy may be beneficial.

Carbapenem-resistant Enterobacteriaceae in special populations: Solid organ transplant recipients, stem cell transplant recipients, and patients with hematologic malignancies

Carbapenem-resistant Enterobacteriaceae (CRE) are a major global public health concern and pose a serious threat to immunocompromised hosts, particularly patients with hematologic malignancies and solid organ (SOT) and stem cell transplant recipients. In endemic areas, carbapenem-resistant Klebsiella pneumoniae infections occur in 1-18% of SOT recipients, and patients with hematologic malignancies represent 16-24% of all patients with CRE bacteremia. Mortality rates approaching 60% have been reported in these patient populations. Early diagnosis and rapid initiation of targeted therapy is critical in the management of immunocompromised hosts with CRE infections, as recommended empiric regimens are not active against CRE. Therapeutic options are limited by antibiotic-associated toxicities, interactions with immunosuppressive agents, and paucity of antibiotic options currently available. Prevention of CRE infection in these patients requires a multidisciplinary approach involving hospital epidemiology and antimicrobial stewardship. Large, multicenter studies are needed to develop risk-stratification tools to assist in guiding the management of these individuals.

Bacterial bloodstream infections in the allogeneic hematopoietic cell transplant patient: new considerations for a persistent nemesis

Bacterial bloodstream infections (BSI) cause significant transplant-related morbidity and mortality following allogeneic hematopoietic cell transplantation (allo-HCT). This manuscript reviews the risk factors for and the bacterial pathogens causing BSIs in allo-HCT recipients in the contemporary transplant period. In addition, it offers insight into emerging resistant pathogens and reviews clinical management considerations to treat and strategies to prevent BSIs in allo-HCT patients.

Gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy in the years 2000

AIM: To review gastrointestinal and liver infections in children undergoing antineoplastic chemotherapy. To look at gut microflora features in oncology children.

METHODS: We selected studies published after year 2000, excluding trials on transplanted pediatric patients. We searched English language publications in MEDLINE using the keywords: “gastrointestinal infection AND antineoplastic chemotherapy AND children”, “gastrointestinal infection AND oncology AND children”, “liver infection AND antineoplastic chemotherapy AND children”, “liver abscess AND chemotherapy AND child”, “neutropenic enterocolitis AND chemotherapy AND children”, “thyphlitis AND chemotherapy AND children”, “infectious diarrhea AND children AND oncology”, “abdominal pain AND infection AND children AND oncology”, “perianal sepsis AND children AND oncology”, “colonic pseudo-obstruction AND oncology AND child AND chemotherapy”, “microflora AND children AND malignancy”, “microbiota AND children AND malignancy”, “fungal flora AND children AND malignancy”. We also analysed evidence from several articles and book references.

RESULTS: Gastrointestinal and liver infections represent a major cause of morbidity and mortality in children undergoing antineoplastic chemotherapy. Antineoplastic drugs cause immunosuppression in addition to direct toxicity, predisposing to infections, although the specific risk is variable according to disease and host features. Common pathogens potentially induce severe diseases whereas opportunistic microorganisms may attack vulnerable hosts. Clinical manifestations can be subtle and not specific. In addition, several conditions are rare and diagnostic process and treatments are not standardized. Diagnosis may be challenging, however early diagnosis is needed for quick and appropriate interventions. Interestingly, the source of infection in those children can be exogenous or endogenous. Indeed, mucosal damage may allow the penetrance of endogenous microbes towards the bowel wall and their translocation into the bloodstream. However, only limited knowledge of intestinal dysbiosis in oncology children is available.

CONCLUSION: The diagnostic work-up requires a multimodal approach and should be implemented (also by further studies on new biomarkers) for a prompt and individualized therapy.

Carbapenem-Resistant Non-Glucose-Fermenting Gram-Negative Bacilli: the Missing Piece to the Puzzle

The non-glucose-fermenting Gram-negative bacilli Pseudomonas aeruginosa and Acinetobacter baumannii are increasingly acquiring carbapenem resistance. Given their intrinsic antibiotic resistance, this can cause extremely difficult-to-treat infections. Additionally, resistance gene transfer can occur between Gram-negative species, regardless of their ability to ferment glucose. Thus, the acquisition of carbapenemase genes by these organisms increases the risk of carbapenemase spread in general. Ultimately, infection control practitioners and clinical microbiologists need to work together to determine the risk carried by carbapenem-resistant non-glucose-fermenting Gram-negative bacilli (CR-NF) in their institution and what methods should be considered for surveillance and detection of CR-NF.