Infection control issues in patients with haematological malignancies in the era of multidrug-resistant bacteria

Multifunctional cyclic biomimetic peptides: Self-assembling nanotubes for effective treatment of sepsis

Antibiotic abuse has led to an increasingly serious risk of antimicrobial resistance, developing alternative antimicrobials to combat this alarming issue is urgently needed. Rhesus theta defensin-1 (RTD-1) is a theta-defensin contributing to broad-spectrum bactericidal activity via the mechanisms of membrane perturbation. Intriguingly, human defensin-6 (HD6), an enteric defensin secreted by Paneth cells without direct bactericidal effect, could self-assembled into fibrous networks to trap enteric pathogens for assistance of innate immunity. The direct bactericidal action of RTD-1 and the bacterial trapping of HD6 inspire a promising antimicrobial paradigm for unique antibacterial strategies. In this study, we utilized the principle of alternating arrangement of D- and L-amino acids in cyclic peptides, which endows them with the potential to self-assemble into nanotubes, mimic the antimicrobial processes of RTD-1 and HD6. We designed and synthesized five cyclic biomimetic peptides (CBPs), among these biomimetics, CBP-4, which possessed a nanotube-like structure, demonstrated the ability to directly and rapidly disrupt the cell membranes of Gram-positive S. aureus and MRSA, while also targeting the surfaces of Gram-negative E. coil using its nanofibrous network to capture bacteria, preventing invasion and migration, and indirectly killing the bacteria. Moreover, CBP-4 eliminated pathogens, inhibited excessive inflammatory responses caused by infections, and maintained immune system homeostasis in septic mice. By fully emulating the antimicrobial mechanisms of both RTD-1 and HD6, CBP-4 showed promising potential for anti-infectious therapies.

The frequency of AmpC overproduction, OprD downregulation and OprM efflux pump expression in Pseudomonas aeruginosa: A comprehensive meta-analysis

OBJECTIVES

Pseudomonas aeruginosa is a major opportunistic pathogen responsible for a wide range of infections. The emergence of antibiotic resistance in this pathogen poses a significant public health challenge. This study aims to conduct a comprehensive meta-analysis of studies conducted in Iran to determine the frequency of key antibiotic resistance mechanisms in Pseudomonas aeruginosa and their association with multidrug-resistant and extensively drug-resistant strains or pandrug-resistant strains.

METHODS

Systematic database searches encompassing literature up to June 2023 were undertaken. The selected studies centered on OprD downregulation, efflux pump (mexAB-OprM, mexXY-OprM) expression, and AmpC overproduction. Extracted data were synthesised in a meta-analysis for pooled frequency determination of each resistance mechanism.

RESULTS

In total, 24 studies were included. OprD downregulation exhibited a pooled frequency of 61%. Efflux pump component frequency ranged from 48% to 77.5%. AmpC overproduction was identified in 29.1% of isolates. Polymyxin B and colistin demonstrated lower antibiotic resistance rates, with pooled frequency of 1% and 1.6%, respectively. Conversely, resistance to other antibiotics ranged widely, with pooled frequency spanning 38.4% to 98.2%.

CONCLUSIONS

This study underscores the concerning frequency of diverse antibiotic resistance mechanisms in Pseudomonas aeruginosa strains from Iran. Concurrent OprD downregulation, mexAB, mexXY, OprM expression, and AmpC overproduction highlight the urgent need for stringent infection control and prudent antibiotic usage to curb the dissemination of these resistant strains.

PROSPERO

CRD42022379311.

Thrombosis and infections associated with PICC in onco-hematological patients, what is their relevance?

PURPOSE

Peripherally inserted central venous catheters (PICC) in the onco-hematological patients may be associated with thrombosis or infections that may have short- to medium-term repercussions.

MATERIAL AND METHODS

Single-centre retrospective analysis of a prospectively collected cohort. Primary objective was to establish the PICC-thrombosis and infections incidence. Secondary objectives were to analyze profile of patients suffering from these complications and variables associated with an increased likelihood of developing these events.

RESULTS

549 patients were recruited. 58.5% (n = 321) were oncology patients and 41.5% (n = 228) hematology patients. The incidence of PICC-associated thrombosis was 3.5% (n = 19). Thrombosis was associated with progression of the underlying malignant pathology in 10.6% (n = 2) of cases. No association was found between clinical variables analysed and development of thrombosis. Incidence of PICC-associated infections was 7.65% (n = 42). In the 30 days prior to PICC infection, 57.1% (n = 24) had a febrile syndrome of another focus, 73.8% (n = 11) had been hospitalized, 49.5% (n = 25) had a neutrophil count of 0-500 cells/mm3 and 47.6% (n = 20) had an episode of neutropenic fever. Variables significantly associated with the development of infection were hematological patients, high-flow PICC, 3-lm PICC or PICC insertion because of administration of vesicant therapy.

CONCLUSIONS

Incidence of PICC-associated thrombosis is low and apparently less prognostically aggressive than other forms of thrombosis associated with cancer, without identify predictive factors. Infection was more prevalent and the identification of risk factors in our series could facilitate its prevention.

AMP-Mimetic Antimicrobial Polymer-Involved Synergic Therapy with Various Coagents for Improved Efficiency

The misuse of antibiotics contributes to the emergence of multidrug-resistant (MDR) bacteria. Infections caused by MDR bacteria are rapidly evolving into a significant threat to global healthcare due to the lack of effective and safe treatments. Antimicrobial peptides (AMPs) with broad-spectrum antibacterial activity kill bacteria generally through a membrane disruption mechanism; hence, they tend not to induce resistance readily. However, AMPs exhibit disadvantages, such as high cost and susceptibility to proteolytic degradation, which limit their clinical application. AMP-mimetic antimicrobial polymers, with low cost, stability to proteolysis, broad-spectrum antimicrobial activity, negligible antimicrobial resistance, and rapid bactericidal effect, have received extensive attention as a new type of antibacterial drugs. Lately, AMP-mimetic polymer-involved synergic therapy provides a superior alternative to combat MDR bacteria by distinct mechanisms. In this Review, we summarize the AMP-mimetic antimicrobial polymers involved in synergic therapy, particularly focusing on the different combinations between the polymers with commercially available antimicrobials, organic small molecule photosensitizers, inorganic nanomaterials, and nitric oxide.

Implementing an Antimicrobial Stewardship Program in an Oncology Center in Lima, Peru: A Model for Low- and Middle-Income Countries

Our center launched the first antimicrobial stewardship program in Peru. From 2016 to 2023, the proportion of antimicrobial prescriptions audited increased from 60% to 95%, and 65% to 95% of recommendations were accepted. Vancomycin and meropenem use dropped by 95% and 84%, respectively. The proportion of recommendations for surgical prophylaxis exceeded 90%.

Impact of multidrug resistance on outcomes in hematologic cancer patients with bacterial bloodstream infections

Despite the improved outcomes in patients with hematological malignancies, infections caused by multidrug-resistant organisms (MDROs) pose a new threat to these patients. We retrospectively reviewed the patients with hematological cancer and bacterial bloodstream infections (BSIs) at a tertiary hospital between 2003 and 2022 to assess the impact of MDROs on outcomes. Among 328 BSIs, 81 (24.7%) were caused by MDROs. MDRO rates increased from 10.3% (2003-2007) to 39.7% (2018-2022) (P < 0.001). The 30-day mortality rate was 25.0%, which was significantly higher in MDRO-infected patients than in non-MDRO-infected patients (48.1 vs. 17.4%; P < 0.001). The observed trend was more pronounced in patients with newly diagnosed diseases and relapsed/refractory disease but less prominent in patients in complete remission. Among MDROs, carbapenem-resistant Gram-negative bacteria exhibited the highest mortality, followed by vancomycin-resistant enterococci, methicillin-resistant Staphylococcus aureus, and extended-spectrum β-lactamase-producing Enterobacteriaceae. Multivariate analysis identified independent risk factors for 30-day mortality as age ≥ 65 years, newly diagnosed disease, relapsed/refractory disease, MDROs, polymicrobial infection, CRP ≥ 20 mg/L, and inappropriate initial antibiotic therapy. In conclusion, MDROs contribute to adverse outcomes in patients with hematological cancer and bacterial BSIs, with effects varying based on the underlying disease status and causative pathogens. Appropriate initial antibiotic therapy may improve patient outcomes.

High mortality associated with inappropriate initial antibiotic therapy in hematological malignancies with Klebsiella pneumoniae bloodstream infections

Bloodstream infections caused by multidrug-resistant organisms such as Klebsiella pneumoniae are a significant challenge in managing hematological malignancies. This study aims to characterize the epidemiology of Klebsiella pneumoniae bloodstream infections specifically in patients with hematological malignancies, delineate the patterns of initial antibiotic therapy, assess the prevalence of resistant strains, identify risk factors for these resistant strains, and evaluate factors influencing patient outcomes. A retrospective analysis was conducted at a single center from January 2017 to December 2020, focusing on 182 patients with hematological malignancies who developed Klebsiella pneumoniae bloodstream infections. We compared the 30-day mortality rates between patients receiving appropriate and inappropriate antibiotic treatments, including the effectiveness of both single-drug and combination therapies. Kaplan-Meier survival analysis and multivariate logistic and Cox regression were used to identify factors influencing mortality risk. The 30-day all-cause mortality rate was 30.2% for all patients. The 30-day all-cause mortality rates were 77.2% and 8.8% in patients who received inappropriate initial treatment and appropriate initial treatment (p < 0.001). Inappropriate initial treatment significantly influenced mortality and was a key predictor of 30-day mortality, along with septic shock and previous intensive care unit (ICU) stays. Patients with carbapenem-resistant Klebsiella pneumoniae (CRKP) bloodstream infections exhibited more severe clinical symptoms compared to the CSKP group. The study demonstrates a significant association between empirical carbapenem administration and the escalating prevalence of CRKP and multidrug-resistant K. pneumoniae (MDR-KP) infections. Furthermore, the study identified inappropriate initial antibiotic therapy, septic shock, and ICU admission as independent risk factors for 30-day mortality.

Infection-related mortality and infection control practices in childhood acute myeloid leukemia in a limited resource setting: Experience with the Indonesian national protocol

Background

In resource-limited settings, addressing infections remains a substantial challenge in the management of children with Acute Myeloid Leukemia (AML). In Indonesia, infection-related mortality (IRM) is thought to be high compared to high-income countries. However, there has been no previous study of infection profile and IRM in Indonesian patients with AML.

Objective

This study aimed to describe infections and IRM in children with AML treated according to the Indonesian National AML protocol and to describe the implementation of infection control practices in resource-limited settings.

Methods

This retrospective observational study used secondary data from the medical records of pediatric patients with AML treated with the National Protocol at Dr. Sardjito Hospital, Yogyakarta, Indonesia, from April 2012 to September 2018. Essential patient characteristics, time of IRM, and cause of death were recorded, and infection control practices were observed. Data were analyzed using descriptive statistics.

Results

113 patients with AML were treated with the National protocol, and 83 met the inclusion criteria. Infections occurred in 69 (83%) patients with a total of 123 episodes (mean 1.8/patient). Death was seen in 48 (58%) patients, with 19 (23%) IRM. The majority of infections were in the gastrointestinal tract (n = 51, 30.5%), sepsis (n = 29, 17%), and respiratory tract (n = 28, 17%). Infections mostly occurred during the first induction (41%). There were 90 (73%) episodes of clinically documented infection and 33 (27%) episodes of microbiologically documented infection. The positivity rate of blood cultures was only 27%. The majority of bacteria detected were gram-negative (n = 25, 69%), and among them were Klebsiella pneumonia (19%) and Escherichia coli (19%). Candida albicans was detected in 1 (2%) culture. Suboptimal infection prevention and control were found in the clinical practice.

Conclusion

Infections and infection-related mortality in children with AML treated using the National protocol were frequent, mainly occurring during the first induction phase. Compliance with infection prevention and control measures needs improvement. Urgent attention is required for better supportive care, including isolation rooms, antibiotics, and antifungals. The predominance of Gram-negative bacterial infections highlights the necessity for further research into effective prophylaxis. Enhanced healthcare and nursing professional vigilance and tailored antibiotic strategies are vital. Improving compliance and ensuring adequate supportive care resources are essential, emphasizing nursing's pivotal role. Further research is crucial to drive advancements in infection control strategies.

Microbiological and Molecular Study of Paranasal Sinus Infections of Children with Malignancy and Unknown Origin Fever in Markazi Province, Iran

Background

Children with malignancies are vulnerable to various infections, including sinus infections. Sinusitis is primarily caused by bacterial infections, followed by fungal infections. Due to this, evaluating the occurrence, diversity, and antibiotic susceptibility patterns of bacterial species that cause paranasal sinus infections in children with malignancy and unexplained fever is important.

Objective

To investigate the bacterial species accountable for sinusitis in children with malignancy and unexplained fever, and determine their susceptibility to antibiotics.

Methods

The study involved collecting 90 sinus samples from children aged 5 to 15 years with malignancy in Arak City, Iran. The isolates were identified using a combination of phenotypic, biochemical, and molecular techniques, including specific polymerase chain reaction and 16S ribosomal RNA gene sequencing. Drug susceptibility testing was performed following the Clinical & Laboratory Standards Institute 2021 guidelines.

Results

A total of 36 isolates (40%) were obtained, including 4 isolates of Nocardia (11.12%), 4 isolates of Escherichia coli (11.12%), 3 isolates of Klebsiella pneumoniae (8.33%), 5 isolates of Pseudomonas aeruginosa (13.88%), 3 isolates of Acinetobacter baumannii (8.33%), 4 isolates of Staphylococcus aureus (11.12%), 3 isolates of Staphylococcus epidermidis (8.33%), 5 isolates of Streptococcus agalactiae (13.88%), 2 isolates of Streptococcus pneumoniae (5.55%), and 3 isolates of Enterococcus faecium (8.33%). The isolates showed the most sensitivity to imipenem and trimethoprim-sulfamethoxazole and the least sensitivity to erythromycin and tetracycline.

Conclusions

The findings of the study indicate that sinusitis can contribute to fever of unknown origin in patients with cancer. Therefore, it is recommended to use a combination of molecular and phenotypic methods for accurate identification of isolates. This approach can provide more reliable and precise results, leading to better diagnosis and treatment of sinusitis infections in children with malignancy.

Risk factors for nosocomial rectal colonisation with carbapenem-resistant Gram-negative bacilli in children with haematological malignancies: a case-control study

BACKGROUND

Rectal colonisation with carbapenem-resistant Gram-negative bacilli (CR-GNB) may cause CR-GNB infection in children with haematological malignancies (HMs) haematological. To date, information on its epidemiology is limited. This study aimed to assess the the risk factors for rectal colonisation with CR-GNB in children with HMs.

METHODS

A case-control study in a tertiary children's hospital in Hangzhou City, was conducted between July 2019, and September 2021. Based on the hospitalisation date, children in the CR-GNB colonisation group and control groups were matched at a ratio of 1:2. Conditional logistic regression models were used to compute the adjusted odds ratios (aORs) and 95% confidence intervals (CIs) of the risk factors for CR-GNB rectal colonisation in children with HMs.

RESULTS

A total of 85 non-duplicated CR-GNB isolates were collected from rectal swab samples of 69 children with HMs. The 30-day mortality rates were 5.8% in the CR-GNB colonisation group and 0% in the control group (P = 0.020).colonisation In the conditional logistic regression model, the aORs were 6.84 (95% CI 1.86-25.20) for acute myeloid leukemia (AML) or acute lymphoblastic leukemia (ALL), 4.16 (95% CI 1.17-14.84) for prior concomitant infections within the last 1 month, 2.33 (95% CI 1.16-4.69) for prior carbapenems usage within the last 1 month and 7.46 (95% CI 1.81-30.67) for prior hematopoietic stem-cell transplantation (HSCT).

CONCLUSION

AML/ALL, prior concomitant infections within the last 1 month, prior carbapenems usage within the last 1 month, and prior HSCT are associated with an increased risk of rectal colonisation with CR-GNB in children with HMs.

Contact tracing for vancomycin-resistant Enterococcus faecium (VRE): evaluation of the Dutch policy of quintuple screening cultures

Detection of vancomycin-resistant Enterococcus faecium (VRE) is hampered by low sensitivity of rectal swab cultures. This study aimed to define the number of screening cultures needed to increase sensitivity to detect VRE transmission, and to determine time from presumed exposure to detectable colonization. In a tertiary care setting, we retrospectively analyzed data from 9 VRE outbreaks. As a proxy or estimation for time to detectable colonization, the time between first positive culture of the presumed index patient and that of their contacts was determined. Only 64% of secondary cases were positive in the first out of five cultures. By using the first three out of five rectal swabs, 89% (95%CI: 78-95%) of all secondary cases would have been identified. The median number of days between the positive culture of the index patient and the first positive culture of secondary cases was 9 days. Eleven percent of secondary cases would have been missed if only three rectal samples would have been obtained. Furthermore, our results show that one or more rectal swabs taken around day 9 after presumed exposure should at least be included in the screening approach. In our setting, obtaining a fourth and a fifth rectal swab showed a relevant additional value compared to only one to three swabs. Our findings are useful for determining the most effective VRE contact tracing approach to prevent transmission.

Oral health in patients scheduled for hematopoietic stem cell transplantation in the Orastem study

Despite advances in transplant medicine, prevalence of complications after hematopoietic stem cell transplantation (HSCT) remains high. The impact of pre-HSCT oral health factors on the incidence and severity of complications post-HSCT is poorly understood. The aim of this prospective, observational study was to analyze oral health in patients planned for HSCT. Patients ≥18 years requiring HSCT were included from five sites between 2011-2018. General health, oral findings and patient-reported symptoms were registered in 272 patients. Oral symptoms around disease onset were reported by 43 patients (15.9%) and 153 patients (58.8%) reported oral complications during previous chemotherapy. One third of patients experienced oral symptoms at the oral examination before conditioning regimen and HSCT. In total, 124 (46.1%) patients had dental caries, 63 (29.0%) had ≥one tooth with deep periodontal pockets, 147 (75.0%) had ≥one tooth with bleeding on probing. Apical periodontitis was observed in almost 1/4 and partially impacted teeth in 17 (6.3%) patients. Oral mucosal lesions were observed in 84 patients (30.9%). A total of 45 (17.4%) of 259 patients had at least one acute issue to be managed prior to HSCT. In conclusion, oral symptoms and manifestations of oral disease were prevalent in patients planned for HSCT. The extent of oral and acute dental diseases calls for general oral screening of patients pre-HSCT.

Infection prevention requirements for the medical care of immunosuppressed patients: recommendations of the Commission for Hospital Hygiene and Infection Prevention (KRINKO) at the Robert Koch Institute

In Germany, guidelines for hygiene in hospitals are given in form of recommendations by the Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, "KRINKO"). The KRINKO and its voluntary work are legitimized by the mandate according to § 23 of the Infection Protection Act (Infektionsschutzgesetz, "IfSG"). The original German version of this document was published in February 2021 and has now been made available to the international professional public in English. The guideline provides recommendations on infection prevention and control for immunocompromised individuals in health care facilities. This recommendation addresses not only measures related to direct medical care of immunocompromised patients, but also management aspects such as surveillance, screening, antibiotic stewardship, and technical/structural aspects such as patient rooms, air quality, and special measures during renovations.

Promising Photocytotoxicity of Water-Soluble Phtalocyanine against Planktonic and Biofilm Pseudomonas aeruginosa Isolates from Lower Respiratory Tract and Chronic Wounds

Alternative methods of killing microbes have been extensively researched in connection with the widespread appearance of antibiotic resistance among pathogenic bacteria. In this study, we report on in vitro antimicrobial phototoxicity research of cationic phthalocyanine with 2-(4-N-methylmorpholin-4-ium-4-yl)ethoxy substituents against selected clinical strains of Pseudomonas aeruginosa isolated from the lower respiratory tract and chronic wounds. The microorganisms tested in the research were analyzed in terms of drug resistance and biofilm formation. The photocytotoxic effect of phthalocyanine was determined by the reduction factor of bacteria. The studied cationic phthalocyanine at a concentration of 1.0 × 10−4 M, when activated by light, revealed a significant reduction factor, ranging from nearly 4 to 6 log, of P. aeruginosa cells when compared to the untreated control group. After single irradiation, a decrease in the number of bacteria in biofilm ranging from 1.3 to 4.2 log was observed, whereas the second treatment significantly improved the bacterial reduction factor from 3.4 to 5.5 log. It is worth mentioning that a boosted cell-death response was observed after the third irradiation, with a bacterial reduction factor ranging from 4.6 to 6.4 log. According to the obtained results, the tested photosensitizer can be considered as a potential antimicrobial photodynamic therapy against multidrug-resistant P. aeruginosa.

Gram-Negative Bacteria Bloodstream Infections in Patients with Hematological Malignancies - The Impact of Pathogen Type and Patterns of Antibiotic Resistance: A Retrospective Cohort Study

Background

Enterobacteriaceae (EB) and non-fermentative bacteria (NFB) are the main pathogens responsible for gram-negative bloodstream infections (GN-BSI) in patients with hematological malignancies (HMs). These two pathogen types have heterogeneous resistance mechanisms to antibiotics. However, the impact of pathogen species and pattern of antibiotic resistance on the outcomes of patients with HMs remains unclear.

Methods

We retrospectively collected clinical data of patients with HMs at three comprehensive hospitals in Hunan Province, China, between January 2010 and May 2018. The data analyzed the impact that different species and patterns of antibiotic resistance had on the outcome of patients with HMs.

Results

The majority of the 835 monomicrobial isolates collected from patients with HMs and GN-BSIs were Enterobacteriaceae (75.7%). While detections of MDR pathogens in BSIs as a whole are decreasing, sub-analysis shows that detections of extended spectrum β-lactamase-producing (ESBL) Enterobacteriaceae and carbapenem-resistant pathogens in BISs are rising. Comparing different species, the early mortality rate associated with infections caused by NFB was significantly higher than infections caused by Enterobacteriaceae (22.6% vs 9.7%, p < 0.001). Across different multidrug-resistant (MDR) patterns, ESBL bacteria did not have a significant impact on health outcomes. Carbapenem-resistant bacteria, on the other hand, were observed to significantly affect early mortality rate, such as carbapenem-resistant Klebsiella pneumoniae (36.0% vs 7.6%, P < 0.001) and carbapenem-resistant non-fermentative bacteria (44.7% vs 16.5%, P < 0.001).

Conclusion

Our findings suggest that both species and patterns of antibiotic resistance can affect the early mortality of patients with HMs during BSI.

Future developments in training

BACKGROUND

The coronavirus disease 2019 (COVID-19) pandemic has demonstrated the value of highly skilled and extensively trained specialists in clinical microbiology (CM) and infectious diseases (ID). Training curricula in CM and ID must constantly evolve to prepare trainees for future pandemics and to allow trainees to reach their full clinical and academic potential.

OBJECTIVES

In this narrative review, we aim to outline necessary future adaptations in CM and ID training curricula and identify current structural barriers in training with the aim of discussing possibilities to address these shortcomings.

SOURCES

We reviewed literature from PubMed and included selected books and online publications as appropriate. There was no time constraint on the included publications.

CONTENT

Drawing from the lessons learnt during the pandemic, we summarize novel digital technologies relevant to CM and ID trainees and highlight interdisciplinary teamwork and networking skills as important competencies. We centre CM and ID training within the One Health framework and discuss gender inequalities and structural racism as barriers in both CM and ID training and patient care.

IMPLICATIONS

CM and ID trainees should receive training and support developing skills in novel digital technologies, leadership, interdisciplinary teamwork and networking. Equally important is the need for equity of opportunity, with firm commitments to end gender inequality and structural racism in CM and ID. Policy-makers and CM and ID societies should ensure that trainees are better equipped to achieve their professional goals and are better prepared for the challenges awaiting in their fields.

Healthcare-associated blood stream infections in hematological patients in Finland during the years 2006-2016

OBJECTIVES

The aim was to identify the clinical characteristics, outcome, and antimicrobial susceptibility of healthcare-associated bloodstream infections (BSIs) in hematological patients.

METHODS

This retrospectively collected laboratory-based surveillance data include 3404 healthcare-associated BSIs in 2296 patients with a hematological malignancy in hospitals participating in the Finnish Hospital Infection Program from January 1, 2006, to December 31, 2016.

RESULTS

The most common underlying diseases were acute myelogenous leukemia (35%) and non-Hodgkin lymphoma (22%). Gram-positive organisms accounted for 60%-46% and gram-negative organisms for 24%-36% of BSIs in 2006-2016. The most common causative organism was coagulase-negative staphylococci (CoNS) (n = 731). The 7- and 28-day case fatality rates were 5.2% and 11.4%, respectively, and was highest in BSIs caused by Candida species (10.8% and 30.8%). The median age of patients increased from 59 years in 2006-2008 to 62 years in 2015-2016 (P < .01). Five percent of S aureus isolates were resistant to methicillin and five percent of Pseudomonas aeruginosa isolates were multidrug-resistant. Four percent of Klebsiella and seven percent of E coli isolates were resistant to ceftazidime.

CONCLUSIONS

The proportion of gram-positive bacteria decreased and gram-negative bacteria increased over time. The case fatality rate was low and the median age of patients increased during the study.

Impact of mcr-1 on the Development of High Level Colistin Resistance in Klebsiella pneumoniae and Escherichia coli

Plasmid-mediated colistin resistance gene mcr-1 generally confers low-level resistance. The purpose of this study was to investigate the impact of mcr-1 on the development of high-level colistin resistance (HLCR) in Klebsiella pneumoniae and Escherichia coli. In this study, mcr-1-negative K. pneumoniae and E. coli strains and their corresponding mcr-1-positive transformants were used to generate HLCR mutants via multiple passages in the presence of increasing concentrations of colistin. We found that for K. pneumoniae, HLCR mutants with minimum inhibitory concentrations (MICs) of colistin from 64 to 1,024 mg/L were generated. Colistin MICs increased 256- to 4,096-fold for mcr-1-negative K. pneumoniae strains but only 16- to 256-fold for the mcr-1-harboring transformants. For E. coli, colistin MICs increased 4- to 64-folds, but only 2- to 16-fold for their mcr-1-harboring transformants. Notably, mcr-1 improved the survival rates of both E. coli and K. pneumoniae strains when challenged with relatively high concentrations of colistin. In HLCR K. pneumoniae mutants, amino acid alterations predominately occurred in crrB, followed by phoQ, crrA, pmrB, mgrB, and phoP, while in E. coli mutants, genetic alterations were mostly occurred in pmrB and phoQ. Additionally, growth rate analyses showed that the coexistence of mcr-1 and chromosomal mutations imposed a fitness burden on HLCR mutants of K. pneumoniae. In conclusion, HLCR was more likely to occur in K. pneumoniae strains than E. coli strains when exposed to colistin. The mcr-1 gene could improve the survival rates of strains of both bacterial species but could not facilitate the evolution of high-level colistin resistance.

Prevention and management of carbapenem-resistant Enterobacteriaceae in haematopoietic cell transplantation

Carbapenem-resistant Enterobacteriaceae (CRE) infections are associated with high morbidity and mortality rates in haematopoietic cell transplantation (HCT) recipients. Factors like mucositis, neutropenia, prolonged hospital stay, and frequent use of prophylactic antimicrobials make HCT recipients especially susceptible to CRE infections. Low culture positivity rates, delay in microbiological diagnosis, and resistance to empirical antimicrobial therapy for febrile neutropenia are responsible for high mortality rates in HCT recipients infected with CRE. In this review we discuss the epidemiology, diagnosis, and management of CRE infections with particular emphasis on patients undergoing HCT. We emphasise the need for preventive strategies like multidisciplinary antimicrobial stewardship, and pre-emptive screening for CRE colonisation in prospective HCT patients as measures to mitigate the adverse impact of CRE on HCT outcomes. Newer diagnostic tests like polymerase chain reaction and matrix-assisted laser desorption ionisation-time of flight (MALDI-TOF) assay that enable earlier and better identification of CRE isolates are discussed. Antimicrobial agents available against CRE, including newer agents like ceftazidime-avibactam and meropenem-vaborbactam, have been reviewed. We also discuss the data on promising experimental treatments against CRE: phage therapy and healthy donor faecal microbiota transplant. Finally, this review puts forth recommendations as per existing literature on diagnosis and management of CRE infections in blood and marrow transplant (BMT) unit.

First Insights into Clinical and Resistance Features of Infections by Klebsiella pneumoniae among Oncological Patients from a Referral Center in Amazon Region, Brazil

Klebsiella pneumoniae appears as one of the most prevalent pathogens among cancer patients. The present study investigates the clinical, epidemiological and microbiological aspects related to infections caused by K. pneumoniae in cancer patients treated at an oncology referral center in the state of Pará, Amazon region, Brazil. Between July 2017 to July 2019, an epidemiological, observational, cross-sectional study, with a descriptive and analytical approach was conducted, including patients with confirmed diagnosis of cancer who acquired infection by K. pneumoniae 72 h after hospital admission. K. pneumoniae isolates included in the study were obtained from different clinical materials (blood, urine, catheter tip and bladder catheter, orotracheal secretions, oncological and surgical wounds). Antimicrobial susceptibility testing and molecular detection of the carbapenemase-encoding genes were performed. A high prevalence of MDR K. pneumoniae isolates was observed, including two colistin-resistant isolates and seven isolates harboring bla_KPC-1 gene. To conclude, our findings provide the firsts insights into the epidemiology and infection by K. pneumoniae in the state of Pará, Brazil, and may be useful on treatment guidance and establishment of strategies to control the spread of resistance strains of K. pneumoniae in the region.

The impact of comprehensive air purification on patient duration of stay, discharge outcomes, and health care economics: A retrospective cohort study

BACKGROUND

Infectious airborne and surface pathogens constitute a substantial and poorly explored source of patient subclinical illness and infections. With that in mind, a system of advanced air purification technology was designed to destroy the DNA and RNA of all bacteria, fungi, and viruses. This study compares the effects of advanced air purification technology versus high efficiency particulate air filtration with respect to certain metrics of health care economics and resource utilization at a large, community-based, urban hospital. Our hypothesis was that the use of the advanced air purification technology would decrease health care durations of stay, lead to fewer nonhome discharges, and decrease hospital charges.

METHODS

After the installation of advanced air purification technology, 3 resultant air purification "zones" were established: zone C, a control floor with high efficiency particulate air filtration; zone B, a mixed high efficiency particulate air and advanced air purification technology floor; and zone A, a comprehensive advanced air purification technology remediation. This study included nonbariatric surgical patients admitted to any zone between December 2017 and December 2018, with reported case mix index on discharge. We analyzed hospital duration of stays, discharge destination, and hospital charges with adjustment for severity of illness using the case mix index. The likelihood of mortality, health care-associated infection, and readmission for each study zone was examined using logistic regression adjusting for case mix index, age, sex, and source of admission.

RESULTS

The study included 1,002 patients across the 3 zones, with mean age of 55.8 years (53.7% female), average case mix index of 1.98, and mortality of 1.7%. Compared with zone C, patients in zones A and B demonstrated decreased hospital stays, a greater percentage of home discharges (86.5-87.8% vs 64.7%), and less hospital charges. In addition, logistic regression modeling performed on 999 study patients showed that the likelihood of mortality, hospital-acquired infections, and readmissions did not differ among the 3 zones. A trend toward a lesser incidence of hospital-acquired infections was noted in zones A and B (0.40% and 0.48%, respectively) when compared with zone C (0.63%).

CONCLUSION

Patients in the advanced air purification technology zones demonstrated statistically significant improvements in durations of stay, discharge to home, and costs after adjusting for case mix index. In addition, a trend toward fewer hospital-acquired infections in advanced air purification technology zones was noted. These findings suggest that environmental factors may affect key clinical and economic outcomes, supporting further research in this important and largely unexplored area.

Acute Myeloid Leukemia in Qatar (2010-2016): Clinical, Biological, and Prognostic Factors and Treatment Outcomes

The current study retrospectively evaluated cytogenetic profiles, various prognostic factors, and survival outcomes in 128 acute myeloid leukemia (AML) patients (14 ≤ age ≤ 70 years) admitted to the National Center for Cancer Care and Research (NCCCR), Hamad Medical Corporation, Doha, Qatar, between January 2010 and December 2016. The median age at diagnosis was 43 years, and 80% were less than 60 years old; 75% of patients were male. Cytogenetic analysis was integrated into the World Health Organization 2008 classification and showed that the percentages of normal and abnormal karyotypes were similar, accounting for 48.4% of each group of patients. The AML risk stratification based on cytogenetic analysis resulted in the following distribution: 18% in the favorable risk group, 57% in the intermediate-risk group, 24% in the unfavorable risk group, and 1% unknown. Only 88 patients received therapy with curative intent; 67% achieved complete remission, increasing to 81% after inductions 1 and 2. The median overall survival (OS) and disease-free survival (DFS) in AML patients were 26.6 and 19.5 months, respectively. The 3-year OS and DFS were 40 and 36%, respectively. Prognostic factors including age, gender, white blood cell count, and risk stratification were not significantly associated with treatment outcomes, whereas response to treatment vs. failure was significantly associated with the outcome (p = 0.01). The current study supports the importance of cytogenetics as a useful tool in diagnosis, prognosis, and risk assessment in AML treatment.

Components of the Lectin Pathway of Complement in Haematologic Malignancies

The complement system is activated cascadically via three distinct major routes: classical pathway (CP), alternative pathway (AP) or lectin pathway (LP). The unique factors associated with the latter are collectins (mannose-binding lectin, collectin-10, collectin-11), ficolins (ficolin-1, ficolin-2, ficolin-3) and proteins of the mannose-binding lectin-associated serine protease (MASP) family (MASP-1, MASP-2, MASP-3, MAp19, MAp44). Collectins and ficolins are both pattern-recognising molecules (PRM), reactive against pathogen-associated molecular patterns (PAMP) or danger-associated molecular patterns (DAMP). The MASP family proteins were first discovered as complexes with mannose-binding lectin (MBL) and therefore named MBL-associated serine proteases, but later, they were found to interact with ficolins, and later still, collectin-10 and collectin-11. As well as proteolytic enzymes (MASP-1, MASP-2, MASP-3), the group includes non-enzymatic factors (MAp19, MAp44). In this review, the association-specific factors of the lectin pathway with haematologic malignancies and related infections are discussed.

Associations of ficolins and mannose-binding lectin with acute myeloid leukaemia in adults

We investigated clinical associations of ficolins and mannose-binding lectin (MBL) in 157 patients suffering from acute myeloid leukaemia (AML). Concentrations of ficolin-1, ficolin-2, ficolin-3 and MBL (before chemotherapy) in serum were determined as were selected polymorphisms of the corresponding genes (FCN1, FCN2, FCN3 and MBL2). The control group (C) consisted of 267 healthy unrelated individuals. Median level of ficolin-1 in patients was lower (p < 0.000001) while median levels of ficolin-2, ficolin-3 and MBL were higher (p < 0.000001, p < 0.000001 and p = 0.0016, respectively) compared with controls. These findings were generally associated with AML itself, however the highest MBL levels predicted higher risk of severe hospital infections (accompanied with bacteremia and/or fungaemia) (p = 0.012) while the lowest ficolin-1 concentrations tended to be associated with prolonged (> 7 days) fever (p = 0.026). Genotyping indicated an association of G/G homozygosity (corresponding to FCN1 gene - 542 G > A polymorphism) with malignancy [p = 0.004, OR = 2.95, 95% CI (1.41-6.16)]. Based on ROC analysis, ficolin-1, -2 and -3 may be considered candidate supplementary biomarkers of AML. Their high potential to differentiate between patients from non-malignant controls but also from persons suffering from other haematological cancers (multiple myeloma and lymphoma) was demonstrated.

Comprehensive integrated NGS-based surveillance and contact-network modeling unravels transmission dynamics of vancomycin-resistant enterococci in a high-risk population within a tertiary care hospital

Vancomycin-resistant E. faecium (VRE) are an important cause of nosocomial infections, which are rapidly transmitted in hospitals. To identify possible transmission routes, we applied combined genomics and contact-network modeling to retrospectively evaluate routine VRE screening data generated by the infection control program of a hemato-oncology unit. Over 1 year, a total of 111 VRE isolates from 111 patients were collected by anal swabs in a tertiary care hospital in Southern Germany. All isolated VRE were whole-genome sequenced, followed by different in-depth bioinformatics analyses including genotyping and determination of phylogenetic relations, aiming to evaluate a standardized workflow. Patient movement data were used to overlay sequencing data to infer transmission events and strain dynamics over time. A predominant clone harboring vanB and exhibiting genotype ST117/CT469 (n = 67) was identified. Our comprehensive combined analyses suggested intra-hospital spread, especially of clone ST117/CT469, despite of extensive screening, single room placement, and contact isolation. A new interactive tool to visualize these complex data was designed. Furthermore, a patient-contact network-modeling approach was developed, which indicates both the periodic import of the clone into the hospital and its spread within the hospital due to patient movements. The analyzed spread of VRE was most likely due to placement of patients in the same room prior to positivity of screening. We successfully demonstrated the added value for this combined strategy to extract well-founded knowledge from interdisciplinary data sources. The combination of patient-contact modeling and high-resolution typing unraveled the transmission dynamics within the hospital department and, additionally, a constant VRE influx over time.

Enhanced antimicrobial stewardship based on rapid phenotypic antimicrobial susceptibility testing for bacteraemia in patients with haematological malignancies: a randomized controlled trial

OBJECTIVES

Recently, rapid phenotypic antimicrobial susceptibility testing (AST) based on microscopic imaging analysis has been developed. The aim of this study was to determine whether implementation of antimicrobial stewardship programmes (ASP) based on rapid phenotypic AST can increase the proportion of patients with haematological malignancies who receive optimal targeted antibiotics during early periods of bacteraemia.

METHODS

This randomized controlled trial enrolled patients with haematological malignancies and at least one positive blood culture. Patients were randomly assigned 1:1 to conventional (n = 60) or rapid phenotypic (n = 56) AST. The primary outcome was the proportion of patients receiving optimal targeted antibiotics 72 hr after blood collection for culture.

RESULTS

The percentage receiving optimal targeted antibiotics at 72 hr was significantly higher in the rapid phenotypic AST group (45/56, 80.4%) than in conventional AST group (34/60, 56.7%) (relative risk (RR) 1.42, 95% confidence interval (CI) 1.09-1.83). The percentage receiving unnecessary broad-spectrum antibiotics at 72 hr was significantly lower (7/26, 12.5% vs 18/60, 30.0%; RR 0.42, 95% CI 0.19-0.92) and the mean time to optimal targeted antibiotic treatment was significantly shorter (38.1, standard deviation (SD) 38.2 vs 72.8, SD 93.0 hr; p < 0.001) in the rapid phenotypic AST group. The mean time from blood collection to the AST result was significantly shorter in the rapid phenotypic AST group (48.3, SD 17.6 vs 83.1, SD 22.2 hr).

DISCUSSION

ASP based on rapid phenotypic AST can rapidly optimize antibiotic treatment for bacteraemia in patients with haematological malignancy. Rapid phenotypic AST can improve antimicrobial stewardship in immunocompromised patients.

Antimicrobial Stewardship in Hematological Patients at the intensive care unit: a global cross-sectional survey from the Nine-i Investigators Network

A global cross-sectional survey was performed to gather data on the current treatment of infections caused by multidrug-resistant (MDR) bacteria among hematological patients admitted to ICUs worldwide. The survey was performed in April 2019 using an electronic platform (SurveyMonkey®) being distributed among 83 physicians and completed by 48 (57.8%) responders. ESBL Enterobacteriaceae, carbapenem-resistant K. pneumoniae and carbapenem-resistant P. aeruginosa were the main concerns. Previous MDR infection (34% of responders), MDR colonization (20%) and previous antibiotic exposure within the last 3 months (20.5%) were considered the most relevant risk factors of bloodstream infection (BSI) due to MDR bacteria. In 48.8% of the ICUs, there was no antimicrobial stewardship (AMS) team focused on hematological patients. Updates on local epidemiology of MDR pathogens were provided in 98% of the centers, using phone or verbal communications (56.1% and 53.7%, respectively). In presence of febrile neutropenia, initial therapy consisted of anti-Gram-negative plus anti-Gram-positive antibiotics for 41% of participants. Antibiotic de-escalation and/or discontinuation of therapy were considered as a promising strategy for the prevention of MDR development (32.4%). Factors associated with antibiotic de-escalation were clinical improvement (43.6%) and neutrophil count recovery (12.8%). Infectious Disease consultation and AMS interventions were not determining factors for de-escalation decisions (more than 50% of responders). Infection control and educational programs were valued as necessary measures for implementation by ICU practitioners. These findings should guide future efforts on collaborative team working, improving compliance with adequate treatment protocols, implementing antimicrobial stewardship programs in critically ill hematological patients, and educational activities.

The clinical impact of Stenotrophomonas maltophilia bacteremia on the 30-day mortality rate in patients with hematologic disorders: a single-institution experience

OBJECTIVE

Stenotrophomonas maltophilia (SM) is an important nosocomial pathogen, particularly in immunocompromised patients due to their adverse antimicrobial susceptibility pattern. The objective of this article was to investigate the clinical impact of SM bacteremia on the 30-day mortality rate and identify the risk factors of the cause of mortality in patients with hematologic disorders.

METHODS

We retrospectively reviewed the clinical data in patients diagnosed with hematological disorders and SM bacteremia over an 8-year period from July 2010 to July 2018 at a 248-bed hematology department. We compared patients' clinical characteristics and outcomes between the non-survivor and survivor groups.

RESULTS

The overall incidence of SM bacteremia was 25.1 per 10,000 admissions. There were 59 patients (median age: 35 years; 57.6% males) included in the study with an overall SM bacteremia-related 30-day mortality of 44.1%. Multi-drug resistance was common. In vitro susceptibility is higher to ceftazidime (72.9%), ciprofloxacin (66.1%) and cefoperazone/sulbactam (59.3%). The risk factors identified in the univariate analysis were catheter re-implantation, accompanying polymicrobial infection, inadequate initial antimicrobial treatment, APACHE II score, temperature > 39 °C, septic shock, respiratory failure, and non-remission post treatment for primary diseases. Multivariate analysis further confirmed that inadequate initial antimicrobial treatment, respiratory failure, and non-remission after treatment for hematological diseases are independent risk factors associated with mortality (P = 0.001, 0.002 and 0.007, respectively).

CONCLUSIONS

Our study suggests that SM bacteremia is highly associated with increased mortality in patients with hematologic diseases. Early detection, prompt comprehensive management including initiation of combined sensitive antibiotics, respiratory monitoring and support, platelet infusion, and strategies to improve patients' remission status are recommended to improve the overall survival in patients with SM bacteremia.

Nanosphere's Verigene® Blood Culture Assay to Detect Multidrug-Resistant Gram-Negative Bacterial Outbreak: A Prospective Study on 79 Hematological Patients in a Country with High Prevalence of Antimicrobial Resistance

Infections are a major cause of morbidity and mortality in hematological patients. We prospectively tested a new molecular assay (Verigene^®) in 79 consecutive hematological patients, with sepsis by gram-negative bacteria. A total of 82 gram-negative microorganisms were isolated by blood cultures, of which 76 cases were mono-microbial. Considering the bacteria detectable by the system, the concordance with standard blood cultures was 100%. Resistance genes were detected in 20 of the isolates and 100% were concordant with the phenotypic antibiotic resistance. Overall, this new assay correctly identified 66/82 of all the gram-negative pathogens, yielding a general sensitivity of 80.5%, and providing information on genetic antibiotic resistance in a few hours. This new molecular assay could ameliorate patient management, resulting in a more rational use of antibiotics.

An outbreak of vanA vancomycin-resistant Enterococcus faecium in a hospital with endemic vanB VRE

BACKGROUND

In Australia, vanB vancomycin-resistant Enterococcus faecium (VREfm) has been endemic for over 20 years, but vanA VREfm isolates have rarely been reported.

METHODS

This outbreak report describes an outbreak of vanA VREfm in the intensive care unit (ICU) and cardiothoracic surgery (CTS) wards of a Melbourne hospital in 2015-2016. After the cluster was initially identified in the ICU ward, an active screening programme was implemented. VRE isolates were typed using in silico multi-locus sequence typing. In addition, to screening, enhanced environmental cleaning, chlorhexidine gluconate body washes, and standardisation of the surgical antibiotic prophylaxis regimen were implemented to control the outbreak.

RESULTS

There were 83 new isolates of vanA VREfm recovered from patients in the ICU (n = 31) and CTS (n = 52) wards. Screening identified 78 (94%) of cases. Three patients required treatment for clinical infection with vanA VREfm during the outbreak. The outbreak was polyclonal with 5 different multilocus sequence types carrying the vanA gene (ST17, ST80, ST203, ST252 and ST1421) detected from a subset of isolates (N = 43). The ST17 isolates all carried both the vanA and vanB gene. The intervention bundle resulted in control of the outbreak after 10 months.

CONCLUSION

Geographically, vanA VREfm has previously been uncommon in the region and this outbreak represents a change in local epidemiology. Few VRE outbreaks have been reported in CTS patients. The infection control responses controlled the outbreak within 10-months and may help guide future management of outbreaks.

The Role of Complement Activating Collectins and Associated Serine Proteases in Patients With Hematological Malignancies, Receiving High-Dose Chemotherapy, and Autologous Hematopoietic Stem Cell Transplantations (Auto-HSCT)

We conducted a prospective study of 312 patients (194 with multiple myeloma, 118 with lymphomas) receiving high-dose conditioning chemotherapy and autologous hematopoietic stem cell transplantation (auto-HSCT). Polymorphisms of MBL2 and MASP2 genes were investigated and serial measurements of serum concentrations of mannose-binding lectin (MBL), CL-LK collectin and MASP-2 as well as activities of MBL-MASP-1 and MBL-MASP-2 complex were made. Serum samples were taken before conditioning chemotherapy, before HSCT and once weekly after (totally 4-5 samples); in minority of subjects also 1 and/or 3 months post transplantation. The results were compared with data from 267 healthy controls and analyzed in relation to clinical data to explore possible associations with cancer and with chemotherapy-induced medical complications. We found a higher frequency of MBL deficiency-associated genotypes (LXA/O or O/O) among multiple myeloma patients compared with controls. It was however not associated with hospital infections or post-HSCT recovery of leukocytes, but seemed to be associated with the most severe infections during follow-up. Paradoxically, high MBL serum levels were a risk factor for prolonged fever and some infections. The first possible association of MBL2 gene 3′-untranslated region polymorphism with cancer (lymphoma) in Caucasians was noted. Heterozygosity for MASP2 gene +359 A>G mutation was relatively frequent in lymphoma patients who experienced bacteremia during hospital stay. The median concentration of CL-LK was higher in myeloma patients compared with healthy subjects. Chemotherapy induced marked increases in serum MBL and MASP-2 concentrations, prolonged for several weeks and relatively slighter decline in CL-LK level within 1 week. Conflicting findings on the influence of MBL on infections following chemotherapy of myeloma and lymphoma have been reported. Here we found no evidence for an association between MBL deficiency and infection during the short period of neutropenia following conditioning treatment before HSCT. However, we noted a possible protective effect of MBL during follow-up, and suspected that to be fully effective when able to act in combination with phagocytic cells after their recovery.

Update on infection control practices in cancer hospitals

Therapies in oncology have evolved rapidly over the last years. At the same pace, supportive care for patients receiving cancer therapy has also evolved, allowing patients to safely receive the newest advances in treatment in both an inpatient and outpatient basis. The recognition of the role of infection control and prevention (ICP) in the outcomes of patients living with cancer has been such that it is now a requirement for hospitals and involves multidisciplinary groups. Some unique aspects of ICP for patients with cancer that have gained momentum over the past few decades include catheter-related infections, multidrug-resistant organisms, community-acquired viral infections, and the impact of the health care environment on the horizontal transmission of organisms. Furthermore, as the potential for infections to cross international borders has increased, alertness for outbreaks or new infections that occur outside the area have become constant. As the future approaches, ICP in immunocompromised hosts will continue to integrate emerging disciplines, such as antibiotic stewardship and the microbiome, and new techniques for environmental cleaning and for controlling the spread of infections, such as whole-genome sequencing. CA Cancer J Clin 2018;000:000-000. © 2018 American Cancer Society.

Carbapenem-resistant Gram-negative pathogens in a German university medical center: Prevalence, clinical implications and the role of novel β-lactam/β-lactamase inhibitor combinations

Objectives

To determine the spectrum of infections with multidrug-resistant Gram-negative bacteria (MDR-GNB) and the clinical impact of the newly available betalactam/betalactamase inhibitor combinations ceftolozane/tazobactam and ceftazidime/avibactam in a German academic tertiary care center.

Methods

Retrospective analysis.

Results

Between September 1, 2015 and August 31, 2016, 119 individual patients (0.22% of all hospital admissions) were colonized or infected with carbapenem-resistant MDR-GNB. The species distribution was Pseudomonas aeruginosa, n = 66; Enterobacteriaceae spp., n = 44; and Acinetobacter baumannii, n = 18. In 9 patients, carbapenem-resistant isolates belonging to more than one species were detected. Infection was diagnosed in 50 patients (total: 42.0%; nosocomial pneumonia: n = 23, 19.3%; bloodstream infection: n = 11, 9.2%). Antimicrobial treatment with broad-spectrum antibiotics prior to detection of a carbapenem-resistant isolate was documented in 105 patients (88.2%, prior administration of carbapenems: 62.2%). Nosocomial transmission was documented in 29 patients (24.4%). In 26 patients (21.8%), at least one carbapenem-susceptible, third-generation cephalosporin non-susceptible isolate was documented prior to detection of a carbapenem-resistant isolate belonging to the same species (median 38 days, IQR 23–78). 12 patients (10.1%) had documented previous contact to the healthcare system in a country with high burden of carbapenemase-producing strains. Genes encoding carbapenemases were detected in 60/102 patient isolates (58.8%; VIM-2, n = 25; OXA-48, n = 21; OXA-23-like, n = 10). Susceptibility to colistin was 94.3%. Ceftolozane/tazobactam and ceftazidime/avibactam were administered to 3 and 5 patients, respectively (in-hospital mortality: 66% and 100%). Development of drug-resistance under therapy was observed for both antimicrobials.

Conclusions

i) The major predisposing factors for acquisition of carbapenem-resistant MDR-GNB were selective pressure due to preceding antimicrobial therapy and nosocomial transmission. ii) Colistin remains the backbone of antimicrobial chemotherapy for infections caused by carbapenem-resistant MDR-GNB. iii) Novel β-lactam/β-lactamase inhibitor combinations are of limited usefulness in our setting because of the high prevalence of Ambler class B carbapenemases and the emergence of nonsusceptibility under therapy.

Molecular epidemiology of carbapenem-resistant Pseudomonas aeruginosa in an endemic area: comparison with global data

Carbapenem-resistant Pseudomonas aeruginosa (CRPA) is an endemic problem in certain countries including Greece. CRPA and multidrug-resistant P. aeruginosa (MDRPA) firstly emerged in our region during the 80s, right after the launch of imipenem and meropenem as therapeutic agents against P. aeruginosa infections. The role of outer membrane protein (Opr) inactivation has been known to contribute to imipenem resistance since many years, while efflux overexpression systems have been mainly associated with meropenem resistance. Among carbapenemases, metallo-β-lactamases (MBL) and mostly Verona integron-mediated (VIM) MBL's have played the most crucial role in CRPA emergence. VIM-2 and VIM-4 producing CRPA, usually belonging to clonal complexes (CC) 111 and 235 respectively, have most frequently been isolated. Bla_VIM-2 and bla_VIM-4 are usually associated with a class 1 integron. VIM-17 also has appeared in Greece. On the other hand, other VIM subtypes detected in a global level, such as VIM-3, VIM-5, VIM-6, VIM-7, VIM-11, VIM-14, VIM-15, VIM-16 and VIM-18 have not yet emerged in Greece. However, new VIM subtypes will probably emerge in the future. In addition, MBL carbapenemases other than VIM, detected worldwide have not yet appeared. A single CRPA isolate producing KPC has emerged in our region several years ago. The study of the molecular basis of Opr deficiency and efflux overexpression remains a challenge for the future. In this article, we review the molecular epidemiology of CRPA in an endemic area, compared to global data.

Bloodstream infections in cancer patients. Risk factors associated with mortality

OBJECTIVE

The aim of this study was to evaluate the clinical characteristics and risk factors associated with mortality in cancer patients with bloodstream infections (BSI), analyzing multidrug resistant bacteria (MDR).

METHODS

We conducted a prospective observational study at a cancer referral center from August 2016 to July 2017, which included all BSI.

RESULTS

4220 patients were tested with blood cultures; 496 were included. Mean age was 48 years. In 299 patients with solid tumors, secondary BSI and Central Line-Associated BSI (CLABSI) were the most common (55.9% and 31.8%, respectively). In 197 hematologic patients, primary and mucosal barrier injury (MBI) BSI were the main type (38.6%). Gram-negative were the most frequent bacteria (72.8%), with Escherichia coli occupying the first place (n=210, 42.3%), 48% were Extended-Spectrum Beta-Lactamase (ESBL) producers, and 1.8% were resistant to carbapenems. Mortality at day 30, was 22%, but reached 70% when patients did not receive an appropriate antimicrobial treatment. Multivariate analysis showed that progression or relapse of the oncologic disease, inappropriate antimicrobial treatment, and having resistant bacteria were independently associated with 30-day mortality.

CONCLUSIONS

Emergence of MDR bacteria is an important healthcare problem worldwide. Patients with BSI, particularly those patients with MDR bacteria have a higher mortality risk.

Implementation of an antimicrobial stewardship program for patients with febrile neutropenia

BACKGROUND

We aimed to describe the effectiveness of our standardized protocol for febrile neutropenia (FN), which was targeted to minimize unintended outcomes and reduce antimicrobial consumption.

METHODS

The study was performed in a private hospital with 300 beds. We included all adult hematologic and oncologic cancer inpatients admitted between January 1, 2015-December 31, 2015, and January 1, 2016-May 31, 2017. The outcomes of the study were fatality, infections, and adherence to the antimicrobial stewardship program (ASP).

RESULTS

We included 152 FN attacks of 95 adult inpatients from hematology and oncology wards; of these, 43% were women, and the median age was 57 years. The case fatality rate was 30% in the pre-ASP period and decreased to 11% in the post-ASP period (P = .024). The appropriate adding or changing (P = .006) and appropriate continuation or de-escalation or discontinuation of antimicrobials improved (P < .001). In the post-ASP period, Staphylococcus spp infections (from 22% to 8%, P = .02) and gram-negative infections decreased (from 43% to 20%, P = .003). In the multivariate analysis, appropriate continuation or de-escalation or discontinuation was increased in the post-ASP period (odds ratio [OR], 4.3; 95% confidence interval [CI], 1.82-10.41; P = .001), and gram-positive infections were decreased (OR, 0.32; 95% CI, 0.11-0.95, P = .041). Vancomycin and fluoroquinolone use decreased significantly.

CONCLUSIONS

After implementation of the ASP, the case fatality rate among the patients with FN decreased. Appropriate antimicrobial use increased and overall antimicrobial consumption was reduced. Bacterial infections and Candida infections decreased.

Control of Multidrug-Resistant Pseudomonas aeruginosa in Allogeneic Hematopoietic Stem Cell Transplant Recipients by a Novel Bundle Including Remodeling of Sanitary and Water Supply Systems

Background

Infections by multidrug-resistant Pseudomonas aeruginosa (MDRPa) are an important cause of morbidity and mortality in patients after allogeneic hematopoietic stem cell transplantation (HSCT). Humid environments can serve as a reservoir and source of infection by this pathogen. To minimize the risk of infection from these reservoirs, we performed extensive remodeling of sanitation and water installations as the focus of our hygiene bundle.

Methods

During the reconstruction of our transplantation unit (April 2011-April 2014) we implemented several technical modifications to reduce environmental contamination by and subsequent spreading of MDRPa, including a newly designed shower drain, disinfecting siphons underneath the sinks, and rimless toilets. During a 3-year study period (2012-2014), we tracked the number of patients affected by MDRPa (colonized and/or infected) and the outcome of infected patients, and monitored the environmental occurrence of this pathogen. We further performed whole-genome sequencing of nosocomial MDRPa strains to evaluate genotypic relationships between isolates.

Results

Whereas 31 (9.2%; 18 colonized, 13 infected) patients were affected in 2012 and 2013, the number decreased to 3 in 2014 (17%; 3 colonized, 0 infected). Lethality by MDRPa similarly decreased from 3.6% to 0%. Environmental detection of MDRPa decreased in toilets from 18.9% in 2012-2013 to 6.1% in the following year and from 8.1% to 3.0%, respectively, in shower outlets. Whole-genome sequencing showed close relationships between environmental and patient-derived isolates.

Conclusions

Hospital construction measures aimed at controlling environmental contamination by and spread of MDRPa are effective at minimizing the risk of highly lethal MDRPa infections.

Adjuvant role of SeptiFast to improve the diagnosis of sepsis in a large cohort of hematological patients

Febrile neutropenia and sepsis are common and life-threatening complications in hematological diseases. This study was performed retrospectively in 514 patients treated for febrile neutropenia at our institute, to investigate the clinical usefulness of a molecular tool, LightCycler® SeptiFast test (SF), to promptly recognize pathogens causing sepsis in hematological patients. We collected 1837 blood samples of 514 consecutive hematological patients. The time of processing is short. Overall, 757 microorganisms in 663 episodes were detected by molecular test and standard blood cultures (BC): 73.6% Gram-positive bacteria, 23.9% Gram-negative bacteria, and 2.5% fungal species. This large analysis demonstrated a significant episode-to episode agreement (71.9%) between the two methods, higher in negative samples (89.14%), and a specificity of 75.89%. Clinical variables that gave a statistically significant contribution to their concordance were absolute neutrophil count, ongoing antimicrobial therapy, timing of test execution, and organ localization of infection. The large analysis highlights the potential of molecular-based assays directly performed on blood samples, especially if implementing the detection of antibiotic resistance genes, which was lacking in the used study.

Outbreaks caused by vancomycin-resistant Enterococcus faecium in hematology and oncology departments: A systematic review

Background

Vancomycin-resistance in Enterococcus faecium (VRE) poses a major threat in health care settings. It is well known that patients in hematology and oncology departments are especially at risk of nosocomial VRE acquisition. This systematic review of the literature provides data on the main sources, transmission modes and potential risk factors for VRE acquisition as well as appropriate infection control measures in order to terminate such nosocomial outbreaks.

Methods

Data on nosocomial VRE outbreaks on hematology and oncology wards was retrieved from the Outbreak Database and PubMed.

Results

A total of 35 VRE outbreaks describing 757 affected patients and 77 deaths were included in this review. The most frequent site of pathogen detection were stool samples or rectal swabs (57% of all isolation sites), followed by blood cultures (30%). The most common outbreak source was an index patient. The main modes of transmission were 1) hands of health care workers, 2) contact to a contaminated environment and 3) patient-to-patient contact. The most common risk factor for VRE positivity was prior antibiotic treatment. The most common infection control measures performed were screening and isolating or cohorting of patients.

Conclusion

A rational use of antibiotics in hematology and oncology units is recommended in order to reduce selection pressure on resistant pathogens such as VRE. In addition the importance of hand hygiene should be stressed to all staff whenever possible.

A multi-center prospective study randomizing the use of fat emulsion in intensive glucose control after allogeneic hematopoietic stem cell transplantation using a myeloablative conditioning regimen

BACKGROUND & AIMS

Although parenteral nutrition (PN) is often used after allogeneic hematopoietic stem cell transplantation (allo-HSCT), there is controversy regarding PN management, for instance in the use of fat emulsion and glucose control (GC). To clarify these issues, we conducted a multi-center prospective study with intensive GC, randomizing the use of fat emulsion after allo-HSCT using a myeloablative conditioning regimen.

METHODS

The primary endpoint was the cumulative incidence of documented infectious disease, namely bacterial and fungal infection, at day 100 after allo-HSCT. Between August 2007 and March 2012, we enrolled 81 patients at 5 centers. Excluding 5 ineligible patients, 76 patients received the protocol treatment. The target fasting glucose level was 80-110 mg/dL.

RESULTS

The median follow-up of surviving patients was 1796 days. The cumulative incidences of documented infectious disease at day 100 were 16% (95% confidence interval [CI] 6-29%) in the no-fat group and 19% (95% CI 8-32%) in the fat group, indicating no significant difference. The mean glucose level at 28 days after allo-HSCT was 107 mg/dL in the no-fat group and 111 mg/dL in the fat group. Grade 3 hyperglycemia (>250 mg/dL) and grade 3 hypoglycemia (<40 mg/dL) occurred in 4 patients each (5.3%). Overall survival and non-relapse mortality rates at 4 years were 75% and 11% in the no-fat group and 69% and 8% in the fat group, respectively.

CONCLUSIONS

Irrespective of the use of fat emulsion, the long-term clinical outcomes of the enrolled patients were favorable under intensive GC. To further clarify the benefits of GC after allo-HSCT, a prospective study randomizing the level of GC is warranted.

Multidrug-resistant Enterobacteriaceae, Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus: Three major threats to hematopoietic stem cell transplant recipients

Hematopoietic stem cell transplant (HSCT) recipients are uniquely threatened by the emergence of multidrug-resistant (MDR) bacteria because these patients rely on immediate active antimicrobial therapy to combat bacterial infections. This review describes the epidemiology and treatment considerations for three challenging MDR bacterial pathogens in HSCT recipients: MDR Enterobacteriaceae, including extended-spectrum β-lactamase (ESBL)-producing and carbapenem-resistant Enterobacteriaceae (CRE), Pseudomonas aeruginosa, and vancomycin-resistant Enterococcus (VRE). These bacteria are common causes of infection in this population and bacteremias caused by these organisms are associated with high mortality rates. Carbapenems remain the treatments of choice for serious infections due to ESBL-producing Enterobacteriaceae in HSCT recipients. Administration of β-lactam agents as an extended infusion is associated with improved outcomes in patients with severe infections caused by P. aeruginosa. Older agents used for the treatment of CRE and MDR P. aeruginosa infections, such as polymyxins and aminoglycosides, have major limitations. Newer agents, such as ceftazidime-avibactam and ceftolozane-tazobactam have great potential for the treatment of Klebsiella pneumoniae carbapemenase-producing CRE and MDR P. aeruginosa, respectively, but more pre-clinical and clinical data are needed to better evaluate their efficacy. Daptomycin dosages ≥8 mg/kg/day are recommended to treat VRE infections in this population, particularly in the setting of increasing daptomycin resistance. Strategies to prevent these infections include strict adherence to recommended infection control practices and multidisciplinary antimicrobial stewardship. Last, gastrointestinal screening to guide empirical therapy and the use of polymerase chain reaction-based rapid diagnostics may decrease the time to administration of appropriate therapy for these infections, thereby leading to improved outcomes.

Acute myeloid leukemia and the infectious diseases consultant

Infectious complications following treatment of acute myeloid leukemia (AML) are important causes of morbidity and mortality. The spectrum and complexity of these infections is reflected by the severe net state of immunosuppression of AML patients, that is dynamic and continuously changing, the polypharmacy, including the widespread use of anti-infectives and the complex epidemiology of severe and frequently resistant pathogens afflicting these patients. Infectious diseases (ID) consultants having a critical mass of expertise and intimate knowledge of the intricacies of leukemia care, add considerable value in improving outcomes of patients with AML who develop infections. Furthermore, pharmaco-economic considerations such as length of stay, choice of cost-effective anti-infective program, infection control and antibiotic stewardship strategies create a delicate interplay of the ID consultant and the ecosystem of care of AML patients. This is an increasingly recognized area of cross collaboration and a productive direction for future collaborative practice models and research.

Diagnosis and empirical treatment of fever of unknown origin (FUO) in adult neutropenic patients: guidelines of the Infectious Diseases Working Party (AGIHO) of the German Society of Hematology and Medical Oncology (DGHO)

Fever may be the only clinical symptom at the onset of infection in neutropenic cancer patients undergoing myelosuppressive chemotherapy. A prompt and evidence-based diagnostic and therapeutic approach is mandatory. A systematic search of current literature was conducted, including only full papers and excluding allogeneic hematopoietic stem cell transplant recipients. Recommendations for diagnosis and therapy were developed by an expert panel and approved after plenary discussion by the AGIHO. Randomized clinical trials were mainly available for therapeutic decisions, and new diagnostic procedures have been introduced into clinical practice in the past decade. Stratification into a high-risk versus low-risk patient population is recommended. In high-risk patients, initial empirical antimicrobial therapy should be active against pathogens most commonly involved in microbiologically documented and most threatening infections, including Pseudomonas aeruginosa, but excluding coagulase-negative staphylococci. In patients whose expected duration of neutropenia is more than 7 days and who do not respond to first-line antibacterial treatment, specifically in the absence of mold-active antifungal prophylaxis, further therapy should be directed also against fungi, in particular Aspergillus species. With regard to antimicrobial stewardship, treatment duration after defervescence in persistently neutropenic patients must be critically reconsidered and the choice of anti-infective agents adjusted to local epidemiology. This guideline updates recommendations for diagnosis and empirical therapy of fever of unknown origin in adult neutropenic cancer patients in light of the challenges of antimicrobial stewardship.

Where is the difference between an epidemic and a high endemic level with respect to nosocomial infection control measures? An analysis based on the example of vancomycin-resistant Enterococcus faecium in hematology and oncology departments

Some infection control recommendations distinguish epidemic and endemic levels for infection control. However, it is often difficult to separate long lasting outbreaks from high endemic levels and it remains open, if this distinction is really useful. Aim: To compare infection control measures in endemic and epidemic outbreaks. Methods: The example of vancomycin-resistant Enterococcus faecium outbreaks in haematology or oncology departments was used to analyse differences in infection control measures between outbreaks and high endemic levels. The outbreak database and PubMed, including long lasting outbreaks, were used for this analysis. Two time limits were used for separation: 6 and 12 months. In addition, monoclonal and polyclonal outbreaks were distinguished. Findings: A total of 36 outbreaks were included. 13 outbreaks lasted 6 months or less, 9 outbreaks more than 6 months but at maximum 12 months and 9 more than 12 months. For the remaining outbreaks, no information about their duration was available. Altogether, 11 outbreaks were monoclonal and 20 polyclonal. Considering infection control measures, there were almost no differences between the different groups compared. Patient screening was given up in 37.5% of long lasting outbreaks (>12 months) and hand hygiene not reported in the majority of polyclonal outbreaks (77.8%). Conclusion: Despite many institutions trying to add further infection control measures in case of an outbreak, evidence based infection control measures should be implemented in endemic and epidemic situations. The crucial aspect is probably the degree of implementation and its control in both situations.