A multisite evaluation of antifungal use in critical care: implications for antifungal stewardship

Background

ICUs are settings of high antifungal consumption. There are few data on prescribing practices in ICUs to guide antifungal stewardship implementation in this setting.

Methods

An antifungal therapy (AFT) service evaluation (15 May-19 November 2019) across ICUs at three London hospitals, evaluating consumption, prescribing rationale, post-prescription review, de-escalation and final invasive fungal infection (IFI) diagnostic classification.

Results

Overall, 6.4% of ICU admissions (305/4781) received AFT, accounting for 11.41 days of therapy/100 occupied bed days (DOT/100 OBD). The dominant prescribing mode was empirical (41% of consumption), followed by targeted (22%), prophylaxis (18%), pre-emptive (12%) and non-invasive (7%). Echinocandins were the most commonly prescribed drug class (4.59 DOT/100 OBD). In total, 217 patients received AFT for suspected or confirmed IFI; 12%, 10% and 23% were classified as possible, probable or proven IFI, respectively. Hence, in 55%, IFI was unlikely. Proven IFI (n = 50) was mostly invasive candidiasis (92%), of which 48% had been initiated on AFT empirically before yeast identification. Where on-site (1 → 3)-β-d-glucan (BDG) testing was available (1 day turnaround), in those with suspected but unproven invasive candidiasis, median (IQR) AFT duration was 10 (7-15) days with a positive BDG (≥80 pg/mL) versus 8 (5-9) days with a negative BDG (<80 pg/mL). Post-prescription review occurred in 79% of prescribing episodes (median time to review 1 [0-3] day). Where suspected IFI was not confirmed, 38% episodes were stopped and 4% de-escalated within 5 days.

Conclusions

Achieving a better balance between promptly treating IFI patients and avoiding inappropriate antifungal prescribing in the ICU requires timely post-prescription review by specialist multidisciplinary teams and improved, evidence-based-risk prescribing strategies incorporating rapid diagnostics to guide AFT start and stop decisions.

Acquisition of MDR-GNB in hospital settings: a systematic review and meta-analysis focusing on ESBL-E

INTRODUCTION

Extended-spectrum beta-lactamase-producing Enterobacterales (ESBL-E) and other multi-drug-resistant Gram-negative bacteria (MDR-GNB) have disseminated globally since their discovery in the late 20^th century. Various infection prevention and control measures are in place to prevent nosocomial transmission of these organisms, but their efficacy remains disputed. New literature has emerged in recent years providing further evidence which can be used to formulate effective strategies to tackle this issue in the future.

METHODS

A systematic review was performed to characterize the prevalence of colonization of multi-drug-resistant organisms and subsequent acquisition of these organisms within hospital settings. A meta-analysis was performed to characterize the prevalence and acquisition of ESBL-E in Europe and North America.

RESULTS

Twenty-eight studies fulfilled the inclusion criteria. Escherichia coli formed the main burden of MDR-GNB colonization worldwide. Patient-to-patient transmission of ESBL-E was found to be rare, but increased transmissibility of Klebsiella pneumoniae was described over E. coli. Within European and North American healthcare settings, a meta-analysis of eight studies identified a pooled prevalence of ESBL-E on admission to hospital of 7.91% and an acquisition rate of 3.73%.

DISCUSSION

Low prevalence at the point of hospital admission and insufficient evidence of patient-to-patient transmission suggests that infection prevention and control measures such as universal surveillance screening and single-room isolation are unlikely to be practical or effective interventions in reducing the overall burden of ESBL-E in hospitals, in line with current European guidelines. Instead, it is argued that efforts should be placed on controlling the spread of these organisms and other MDR-GNB in the community, predominantly long-term care facilities.

Expression of CD11c and EMR2 on neutrophils: potential diagnostic biomarkers for sepsis and systemic inflammation

There is a need for cellular biomarkers to differentiate patients with sepsis from those with the non-infectious systemic inflammatory response syndrome (SIRS). In this double-blind study we determined whether the expression of known (CD11a/b/c, CD62L) and putative adhesion molecules [CD64, CD97 and epidermal growth factor (EGF)-like molecule containing mucin-like hormone receptor (EMR2)] on blood neutrophils could serve as useful biomarkers of infection and of non-infectious SIRS in critically ill patients. We studied 103 patients with SIRS, 83 of whom had sepsis, and 50 healthy normal subjects, using flow cytometry to characterize neutrophils phenotypically in whole blood samples. Patients with SIRS had an increased prevalence of neutrophils expressing CD11c, CD64 and EMR2 in comparison with healthy subjects (P < 0.001), but normal expression of CD11a, CD11b, CD62L and CD97. An increase in the percentage of neutrophils bearing CD11c was associated with sepsis, EMR2 with SIRS and CD64 with sepsis and SIRS. Neutrophils expressing CD11c had the highest sensitivity (81%) and specificity (80%) for the detection of sepsis, and there was an association between the percentage of neutrophils expressing EMR2 and the extent of organ failure (P < 0.05). Contrary to other reports, we did not observe an abnormal expression of CD11b or CD62L on neutrophils from patients with SIRS, and suggest that this discrepancy is due to differences in cell processing protocols. We propose that blood neutrophils expressing CD11c and EMR2 be considered as potential biomarkers for sepsis and SIRS, respectively.

Development and validation of a risk model for identification of non-neutropenic, critically ill adult patients at high risk of invasive Candida infection: the Fungal Infection Risk Evaluation (FIRE) Study

BACKGROUND

There is increasing evidence that invasive fungal disease (IFD) is more likely to occur in non-neutropenic patients in critical care units. A number of randomised controlled trials (RCTs) have evaluated antifungal prophylaxis in non-neutropenic, critically ill patients, demonstrating a reduction in the risk of proven IFD and suggesting a reduction in mortality. It is necessary to establish a method to identify and target antifungal prophylaxis at those patients at highest risk of IFD, who stand to benefit most from any antifungal prophylaxis strategy.

OBJECTIVES

To develop and validate risk models to identify non-neutropenic, critically ill adult patients at high risk of invasive Candida infection, who would benefit from antifungal prophylaxis, and to assess the cost-effectiveness of targeting antifungal prophylaxis to high-risk patients based on these models.

DESIGN

Systematic review, prospective data collection, statistical modelling, economic decision modelling and value of information analysis.

SETTING

Ninety-six UK adult general critical care units.

PARTICIPANTS

Consecutive admissions to participating critical care units.

INTERVENTIONS

None.

MAIN OUTCOME MEASURES

Invasive fungal disease, defined as a blood culture or sample from a normally sterile site showing yeast/mould cells in a microbiological or histopathological report. For statistical and economic modelling, the primary outcome was invasive Candida infection, defined as IFD-positive for Candida species.

RESULTS

Systematic review: Thirteen articles exploring risk factors, risk models or clinical decision rules for IFD in critically ill adult patients were identified. Risk factors reported to be significantly associated with IFD were included in the final data set for the prospective data collection.

DATA COLLECTION

Data were collected on 60,778 admissions between July 2009 and March 2011. Overall, 383 patients (0.6%) were admitted with or developed IFD. The majority of IFD patients (94%) were positive for Candida species. The most common site of infection was blood (55%). The incidence of IFD identified in unit was 4.7 cases per 1000 admissions, and for unit-acquired IFD was 3.2 cases per 1000 admissions. Statistical modelling: Risk models were developed at admission to the critical care unit, 24 hours and the end of calendar day 3. The risk model at admission had fair discrimination (c-index 0.705). Discrimination improved at 24 hours (c-index 0.823) and this was maintained at the end of calendar day 3 (c-index 0.835). There was a drop in model performance in the validation sample. Economic decision model: Irrespective of risk threshold, incremental quality-adjusted life-years of prophylaxis strategies compared with current practice were positive but small compared with the incremental costs. Incremental net benefits of each prophylaxis strategy compared with current practice were all negative. Cost-effectiveness acceptability curves showed that current practice was the strategy most likely to be cost-effective. Across all parameters in the decision model, results indicated that the value of further research for the whole population of interest might be high relative to the research costs.

CONCLUSIONS

The results of the Fungal Infection Risk Evaluation (FIRE) Study, derived from a highly representative sample of adult general critical care units across the UK, indicated a low incidence of IFD among non-neutropenic, critically ill adult patients. IFD was associated with substantially higher mortality, more intensive organ support and longer length of stay. Risk modelling produced simple risk models that provided acceptable discrimination for identifying patients at 'high risk' of invasive Candida infection. Results of the economic model suggested that the current most cost-effective treatment strategy for prophylactic use of systemic antifungal agents among non-neutropenic, critically ill adult patients admitted to NHS adult general critical care units is a strategy of no risk assessment and no antifungal prophylaxis.

FUNDING

Funding for this study was provided by the Health Technology Assessment programme of the National Institute for Health Research.

Multiplex molecular testing for management of infectious gastroenteritis in a hospital setting: a comparative diagnostic and clinical utility study

Laboratory diagnosis and clinical management of inpatients with diarrhoea is complex and time consuming. Tests are often requested sequentially and undertaken in different laboratories. This causes prolonged unnecessary presumptive isolation of patients, because most cases are non-infectious. A molecular multiplex test (Luminex(®) Gastrointestinal Pathogen Panel (GPP)) was compared with conventional testing over 8 months to determine diagnostic accuracy, turnaround times, laboratory costs, use of isolation facilities and user acceptability. A total of 262 (12%) patients had a pathogen detected by conventional methods compared with 483 (22.1%) by GPP. Most additional cases were detected in patients developing symptoms in the first 4 days of admission. Additional cases were detected because of presumed improved diagnostic sensitivity but also because clinicians had not requested the correct pathogen. Turnaround time (41.8 h) was faster than bacterial culture (66.5 h) and parasite investigation (66.5 h) but slower than conventional testing for Clostridium difficile (17.3 h) and viruses (27 h). The test could allow simplified requesting by clinicians and a consolidated laboratory workflow, reducing the overall number of specimens received by the laboratory. A total of 154 isolation days were saved at an estimated cost of £30 800. Consumables and labour were estimated at £150 641 compared with £63 431 for conventional testing. Multiplex molecular testing using a panel of targets allowed enhanced detection and a consolidated laboratory workflow. This is likely to be of greater benefit to cases that present within the first 4 days of hospital admission.

Novel H1N1 influenza and Panton-Valentine leukocidin Staphylococcus aureus necrotizing pneumonia

The association between seasonal influenza and staphylococcal pneumonia has long been recognized (Chickering and Park, 1919; Roberts et al, 2008), and both meticillin-resistant Staphylococcus aureus and Panton-Valentine leukocidin S. aureus have been associated with seasonal influenza pandemics (Roberts et al, 2008; Kearns et al, 2009; Murray et al, 2010).

A randomized controlled trial of prophylactic antibiotics (co-amoxiclav) prior to embryo transfer

BACKGROUND

Bacterial contamination of the transfer catheter during embryo transfer is associated with poor clinical outcomes. Antibiotics at the time of embryo transfer may improve outcomes. We evaluated the effect of co-amoxiclav on the rates of bacterial contamination of transfer catheters and clinical pregnancy.

METHODS

On the day of oocyte collection, 350 patients were randomized, with sequentially numbered opaque-sealed envelopes containing treatment allocation assigned randomly by computer, to receive co-amoxiclav on the day before and the day of embryo transfer, or no antibiotics. Following transfer, the catheter tips were cultured and assessed to identify the organism(s) isolated and to quantify the level of the contamination. Couples were followed for 8 weeks to determine whether they had achieved clinical pregnancy. Outcome assessors were blinded to the treatment allocation, and the analysis was by intention to treat.

RESULTS

Antibiotics significantly reduced catheter contamination rates (49.4 versus 62.3%, RR = 0.79, 95% CI: 0.64, 0.97, P = 0.03). There was no difference detected in clinical pregnancy rates between the two groups (36.0 versus 35.5%, P = 0.83) although there was a significant (P = 0.03) association between the level of bacterial contamination and clinical pregnancy rates.

CONCLUSIONS

Co-amoxiclav reduces catheter contamination, but this is not translated into better clinically relevant outcomes such as clinical pregnancy rates. Our findings do not support the routine use of antibiotics at embryo transfer.

Community-acquired Staphylococcus epidermidis endocarditis complicated by splenic disease 9 years after aortic valve replacement

We describe here a case of Staphylococcus epidermidis prosthetic aortic valve endocarditis 9 y after valve replacement. Surprisingly, the microorganism was community-acquired, highly virulent and associated with splenic disease. The patient recovered following emergency valve replacement and prolonged antibiotic therapy. Splenectomy was not required.

Reactivation of coccidioidomycosis in a fit American visitor

The case history is presented of an American visitor, known to have had primary coccidioidomycosis previously, who became very unwell during a visit to the UK. Despite consideration of reactivation of coccidioidomycosis from the outset, other pathogens were identified while Coccidioides immitis was not initially, leading to a delay in treatment.

Why are brain tumours still being missed?

The prediagnosis period of 74 children with primary brain tumours was assessed to examine their presentation and reasons for any delay in diagnosis. Medical case notes were reviewed and parents were interviewed and asked to complete psychological questionnaires. Mean (SD) duration of clinical history was 20.0 (29.1) weeks. Most common symptoms were vomiting (65%) and headache (64%). Only 34% of headaches were always associated with vomiting and only 28% occurred 'early morning'. Changes in the child's personality (47%) were also common. The average number of consultations before diagnosis was 4.6. Migraine was diagnosed in 24% of children and a psychological aetiology in 15%. One quarter of the children had altered levels of consciousness on arrival at the unit. Results indicate that delay in diagnosis still occurs, despite strong parental concern. The nonspecificity of symptoms and a high incidence of psychological symptoms may confound the clinical picture and are considered along with other possible contributory factors.

MRP-8 and MRP-14, two abundant Ca(2+)-binding proteins of neutrophils and monocytes

Two calcium-binding proteins, named migration inhibitory factor-related proteins-8 (MRP-8) and MRP-14, are primarily expressed by circulating human neutrophils and monocytes. Evidence accumulating from the investigations of several independent groups is now leading to an improved understanding of the biology of these proteins. Both MRP-8 and MRP-14 display features characteristic of members of the S100 family of calcium-binding proteins. Some of these features predict functions for MRP-8 and MRP-14 but to date an exact and well-defined function remains elusive. Here we review the available information and highlight evidence that suggests the function of MRP-8 and MRP-14 may be associated with both monocyte and neutrophil activation and the accumulation of these cells in inflammatory sites.

Identification of p8,14 as a highly abundant heterodimeric calcium binding protein complex of myeloid cells

In this report we describe the biochemical characterization of neutrophil and monocyte p8 and p14. Together the two proteins comprise approximately 45% of cytosolic protein in neutrophils and approximately 40-fold less in monocytes. They fractionated together in several chromatographic procedures and were found to exist as a noncovalently associated complex with a stoichiometry of 1:1, named p8,14. Cross-linking experiments showed p8,14 to form heterodimers under conditions simulating the cytosol. An apparent molecular mass of 35,000 daltons was obtained for the p8,14 complex in molecular sizing experiments which suggests the presence of modifications or distinctive structural features. Two major forms of p14 can be identified by two-dimensional gel electrophoresis, both of which form heterodimers with p8. The lower molecular weight variant of p14 lacks Cys-3 (Met-Thr-Cys-Lys-Met...) suggesting that differing translational start sites account for these two forms of p14. A protocol has been devised for the rapid purification of milligram quantities of p8 and p14 from neutrophil cytosol using fast-protein liquid chromatography.

Ionomycin-regulated phosphorylation of the myeloid calcium-binding protein p14

Two associated calcium-binding proteins (CaBPs) have recently been identified specifically in cells of myeloid origin. These proteins have relative molecular masses (Mr) of 8,000 and 14,000 and are variously referred to as the cystic fibrosis antigen, the L1 light chain, MRP-8 or p8, and the L1 heavy chain, MRP14 or p14, respectively. The expression of p8 and p14 seems to be confined to a specific stage of myeloid cell differentiation, because both proteins are expressed in circulating neutrophils and monocytes but not in normal tissue macrophages. In chronic inflammatory conditions, however, such as rheumatoid arthritis, macrophages in affected tissues express both p8 and p14. These proteins are members of a family of CaBPs of low Mr, which include S-100 alpha and beta proteins, calcyclin (2A9), intestinal CaBP and p11. All the proteins have an Mr of approximately 10,000 with the exception of p14 which has a longer C-terminal sequence after the second calcium-binding domain. Little is known about their function, although by analogy with calmodulin they could be molecules involved in intracellular signalling that are activated by an increase in the intracellular Ca2+ concentration ([Ca2+]). Here we report that p14 is phosphorylated in both monocytes and neutrophils. The level of p14 phosphorylation can be increased by elevating the [Ca2+]i using the ionophore ionomycin, but is not affected by activation of protein kinase C using phorbol 12,13-dibutyrate. The phosphorylated residue is threonine at position 113, which is the penultimate amino acid in p14 and contained in the longer 'tail' sequence. Part of this sequence is identical to the neutrophil immobilizing factors NIF-1 and NIF-2, indicating that the phosphorylation event could have a role in the generation of NIF activity in the p14 protein.

Monoclonal antibody 5.5 reacts with p8,14, a myeloid molecule associated with some vascular endothelium

The movement of mononuclear phagocytes and neutrophils from the circulation into tissues is a process which is not completely understood. Monoclonal antibody 5.5 is specific for an 8/14-kDa molecule known variously as the CF antigen, L1 molecule or MRP8 and 14. We show that this molecule, which will be named p8,14 in this study, is expressed in all circulating monocytes and neutrophils as an intracellular product (as well as some types of epithelium). Tissue staining patterns suggest that when monocytes and neutrophils adhere to vascular endothelium, they release this molecule onto the associated endothelium. This process occurs with single monocytes and when monocytes form part of an inflammatory infiltrate. Monoclonal antibody 5.5 does not react with cultured endothelial cells even when stimulated with phorbol ester, tumor necrosis factor, interferon-gamma or interleukin 1 alpha providing further evidence that myeloid cells are the source of the p8,14 in this interactive process. Monocytes which have moved further into such tissues and tissue macrophages in general are monoclonal antibody 5.5 negative, suggesting that the ability to synthesize this molecule may be lost when monocytes leave the circulation and enter tissues. These results indicate that p8,14 plays a role in the interaction between myeloid cells and the vascular endothelium to which they adhere prior to leaving the circulation.