A retrospective study of intravenous pentamidine for Pneumocystis jirovecii pneumonia prophylaxis in adult patients with hematologic malignancies-its utility during respiratory virus pandemics

OBJECTIVES

In hematology, prophylaxis for Pneumocystis jirovecii pneumonia (PCP) is recommended for patients undergoing hematopoietic stem cell transplantation and in selected categories of intensive chemotherapy for hematologic malignancies. Trimethoprim-sulfamethoxazole (TMP-SMX) is the recommended first-line agent; however, its use is not straightforward. Inhaled pentamidine is the recommended second-line agent; however, aerosolized medications were discouraged during respiratory virus outbreaks, especially during the COVID-19 pandemic, in view of potential contamination risks. Intravenous (IV) pentamidine is a potential alternative agent. We evaluated the effectiveness and tolerability of IV pentamidine use for PCP prophylaxis in adult allogeneic hematopoietic stem cell transplantation recipients and patients with hematologic malignancies during COVID-19.

RESULTS

A total of 202 unique patients who received 239 courses of IV pentamidine, with a median of three doses received (1-29). The largest group of the patients (49.5%) who received IV pentamidine were undergoing or had received a hematopoietic stem cell transplant. The most common reason for not using TMP-SMX prophylaxis was cytopenia (34.7%). We have no patients who had breakthrough PCP infection while on IV pentamidine. None of the patients developed an infusion reaction or experienced adverse effects from IV pentamidine.

CONCLUSIONS

Pentamidine administered IV monthly is safe and effective.

Dengue virus infection among renal transplant recipients in Singapore: a 15-year, single-centre retrospective review

INTRODUCTION

Dengue is a mosquito-borne viral infection endemic in Singapore. Its impact on renal transplantation is limited to small case series. We aimed to characterise the clinical presentation and outcomes of dengue infection among renal transplant recipients in Singapore.

METHODS

We conducted a 15-year retrospective review of dengue in renal transplant patients treated at Singapore General Hospital between January 2005 and October 2019. The diagnosis of dengue was made if there were a compatible clinical syndrome and a positive dengue diagnostic assay (dengue non-structural 1 antigen, immunoglobulin M or reverse transcriptase-polymerase chain reaction).

RESULTS

Of the 31 patients diagnosed with dengue, 18 (58.1%) were deceased donor recipients. The median age was 52 (interquartile range [IQR] 40-61) years; 16 (51.6%) were females. The median time to diagnosis was 99 (IQR 18-169) months from transplant. The most common clinical symptoms were fever (87.1%), myalgia (41.9%), gastrointestinal symptoms (38.7%) and headache (25.8%). Nineteen (61.3%) patients had dengue without warning signs, nine (29.0%) had dengue with warning signs, three (9.7%) had severe dengue and 30 (96.8%) were hospitalised. Seventeen (54.8%) patients had graft dysfunction, 16 (94.1%) of whom had recovery of graft function. One (3.2%) patient required dialysis and subsequently died. There were two cases of donor-derived infections (DDIs) with favourable outcomes.

CONCLUSION

Our experience with dengue in renal transplant recipients is concordant with published data. Although graft dysfunction is common, it is often transient with favourable outcomes. Outpatient management may be considered for mild infections. Although dengue DDIs are uncommon, more stringent donor screening may be considered in endemic regions.

Efficacy and safety of shunt surgery in patients with idiopathic normal-pressure hydrocephalus: can we predict shunt response by preoperative magnetic resonance imaging (MRI)?

AIM

The aim of this study was to identify preoperative magnetic resonance imaging (MRI) findings that can predict the shunt responsiveness in idiopathic normal-pressure hydrocephalus (iNPH) patients and to investigate postoperative outcome and complications.

MATERIALS AND METHODS

A total of 192 patients with iNPH who underwent shunt at our hospital between 2000 and 2021 were included to investigate complications. Of these, after exclusion, 127 (1-month postoperative follow-up) and 77 (1-year postoperative follow-up) patients were evaluated. The preoperative MRI features (the presence of tightness of the high-convexity subarachnoid space, Sylvian fissure enlargement, Evans' index, and callosal angle) of the shunt-response and nonresponse groups were compared, and a systematic review was conducted to evaluate whether preoperative MRI findings could predict shunt response.

RESULTS

Postoperative complications within one month after surgery were observed in 6.8% (13/192), and the most common complication was hemorrhage. Changes in corpus callosum were observed in 4.2% (8/192). The shunt-response rates were 83.5% (106/127) in the 1-month follow-up group and 70.1% (54/77) in 1-year follow-up group. In the logistic regression analysis, only Evans' index measuring >0.4 had a significant negative relationship with shunt response at 1-month follow-up; however, no significant relationship was observed at 1-year follow-up. According to our systematic review, it is still controversial whether preoperative MRI findings could predict shunt response.

CONCLUSION

Evans' index measure of >0.4 had a significant relationship with the shunt response in the 1-month follow-up group. In systematic reviews, there is ongoing debate about whether preoperative MRI findings can accurately predict responses to shunt surgery. Postoperative corpus callosal change was observed in 4.2% of iNPH patients.

Improved diagnostic performance of susceptibility-weighted imaging with compressed sensing-sensitivity encoding and neuromelanin-sensitive MRI for Parkinson's disease and atypical Parkinsonism

AIM

To verify the diagnostic performance of the loss of nigrosome-1 on susceptibility-weighted imaging (SWI) with compressed sensing-sensitivity encoding (CS-SENSE) and neuromelanin on neuromelanin-sensitive (NM) magnetic resonance imaging (MRI) for the diagnosis of Parkinson's disease (PD) and atypical Parkinsonism.

MATERIALS AND METHODS

A total of 195 patients who underwent MRI between October 2019 and February 2020, including SWI, with or without CS-SENSE, and NM-MRI, were reviewed retrospectively. Two neuroradiologists assessed the loss of nigrosome-1 on SWI and neuromelanin on the NM-MRI. The result of N-3-fluoropropyl-2-beta-carbomethoxy-3-beta-(4-iodophenyl) nortropane positron-emission tomography (PET) was set as the reference standard.

RESULTS

When CS-SENSE was applied for nigrosome-1 imaging on SWI, the non-diagnostic scan rate was lowered significantly from 19.3% (17/88) to 5.6% (6/107; p=0.004). Diagnosis of PD and atypical Parkinsonism based on the loss of nigrosome-1 on SWI and based on NM-MRI showed good diagnostic value (area under the curve [AUC] 0.821, 95% confidence interval [CI] = 0.755-0.875: AUC 0.832, 95% CI = 0.771-0.882, respectively) with a substantial inter-reader agreement (κ = 0.791 and 0.681, respectively). Combined SWI and neuromelanin had a similar discriminatory ability (AUC 0.830, 95% CI = 0.770-0.880). Similarly, the diagnosis of PD was excellent.

CONCLUSIONS

CS-SENSE may add value to the diagnostic capability of nigrosome-1 on SWI to reduce the nondiagnostic scan rates. Furthermore, loss of nigrosome-1 on SWI or volume loss of neuromelanin on NM-MRI may be helpful for diagnosing PD.

Immune monitoring of prevalent kidney transplant recipients using Torque Teno Virus: Protocol for a single-centre prospective cohort study

INTRODUCTION

Kidney transplant recipients (KTRs) suffer from immunosuppression-related adverse events (iRAEs), such as infections and malignancy from chronic immunosuppression, but are also at risk of graft loss from rejection with underimmunosuppression. Biomarkers that predict both iRAEs and rejection while allowing individualisation of immunosuppression exposure are lacking. Although plasma viral DNA levels of torque teno virus (TTV), a widely prevalent, non-pathogenic virus, have been shown to predict both iRAE and rejection in newly transplanted KTRs within the first year after transplant, its role for prevalent KTRs on stable immunosuppression is less clear.This study aims to determine the prognostic value of TTV levels for severe infections (defined as infections requiring hospitalisation) in prevalent KTRs on stable immunosuppression for at least 3 months and compare it against that of other commonly available biomarkers. The study also aims to explore the relationship between TTV levels and factors affecting the 'net state of immunosuppression' as well as other clinical outcomes.

METHODS AND ANALYSIS

This is a single-centre, prospective, observational cohort study of 172 KTRs on stable immunosuppression for more than 3 months. TTV levels will be measured using the TTV R-GENE kit upon recruitment when study subjects are admitted and when kidney allograft biopsies are performed. Subjects will be monitored for iRAEs and rejection for at least 12 months. The relationship between TTV load and clinical outcomes such as severe infections will be analysed and compared against that from other common biomarkers and previously published predictive scores.

ETHICS AND DISSEMINATION

The study was approved by the SingHealth Centralised Institutional Review Board (2023/2170). The results will be presented at conferences and submitted for publication in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

NCT05836636.

Comparative Activities of Novel Therapeutic Agents against Molecularly Characterized Clinical Carbapenem-Resistant Enterobacterales Isolates

Limited treatment options exist for the treatment of carbapenem-resistant Enterobacterales (CRE) bacteria. Fortunately, there are several recently approved antibiotics indicated for CRE infections. Here, we examine the in vitro activity of various novel agents (eravacycline, plazomicin, ceftazidime-avibactam, imipenem-relebactam, and meropenem-vaborbactam) and comparators (tigecycline, amikacin, levofloxacin, fosfomycin, polymyxin B) against 365 well-characterized CRE clinical isolates with various genotypes. Nonduplicate isolates collected from the largest public health hospital in Singapore between 2007 and 2020 were subjected to antimicrobial susceptibility testing (broth microdilution or antibiotic gradient test strips). Susceptibilities were defined using Clinical and Laboratory Standards Institute (CLSI) or Food and Drug Administration (FDA) interpretative criteria. Sequence types and resistance mechanisms were characterized using short-read whole-genome sequencing. Overall, tigecycline and plazomicin exhibited the highest susceptibility rates (89.6% and 80.8%, respectively). However, the tigecycline susceptibility breakpoint utilized here may be outdated in view of prevailing pharmacokinetic-pharmacodynamic (PK/PD) data. Susceptibility varied by carbapenemase genotype; the β-lactam/β-lactamase inhibitor combinations were equally active (92.3 to 99.2% susceptible) against KPC producers, but only ceftazidime-avibactam retained high susceptibility (98.7%) against OXA-48-like producers. Against metallo-β-lactamase producers, only plazomicin exhibited moderate activity (77.0% susceptible). Aminoglycoside activity was also influenced by carbapenemase genotypes. This work provides an insight into the comparative activity and presumptive utility of novel agents in this geographic region. IMPORTANCE This study determined the susceptibilities of carbapenem-resistant Enterobacterales isolates to various novel antimicrobial agents (ceftazidime-avibactam, imipenem-relebactam, meropenem-vaborbactam, eravacycline, and plazomicin). Whole-genome sequencing was performed for all strains. Our study findings provide insights into the comparative activities of novel agents in this geographic region. Plazomicin and ceftazidime-avibactam exhibited the lowest nonsusceptibility rates and may be considered promising agents in the management of carbapenem-resistant Enterobacterales infections. We note also that antibiotic activity is influenced by genotypes and that understanding the geographic region's molecular epidemiology could aid in the definition of the presumptive utility of novel agents and contribute to antibiotic decision-making.

An outpatient model of care for COVID-19 infected kidney transplant patients - The hospital-at-home

BACKGROUND

The COVID-19 pandemic is protracted and episodic surges from viral variants continue to place significant strain on healthcare systems. COVID-19 vaccines, antiviral therapy and monoclonal antibodies have significantly reduced COVID-19 associated morbidity and mortality. Concurrently, telemedicine has gained acceptance as a model of care and a tool for remote monitoring. These advances allow us to safely transit our inpatient-based care for COVID-19 infected kidney transplant recipients (KTRs) to a hospital-at-home (HaH) model of care.

METHODS

KTRs with PCR-proven COVID-19 infection were triaged by teleconsult and laboratory tests. Suitable patients were enrolled into the HaH. Remote monitoring via teleconsults were conducted daily until patients were de-isolated based on a time-based criterion. Monoclonal antibodies were administered in a dedicated clinic where indicated.

RESULTS

Eighty-one KTRs with COVID-19 were enrolled into the HaH between February and June 2022, 70 (86.4%) completed HaH recovery without complications. Eleven (13.6%) patients required inpatient hospitalization for medical issues (n = 8) and weekend monoclonal antibody infusion (n = 3). Patients requiring inpatient hospitalization had longer transplant vintage (15 years vs. 10 years, p = .03), anaemia (haemoglobin 11.6 g/dL vs. 13.1 g/dL, p = .01), lower eGFR (39.8 vs. 62.9 mL/min/1.73 m² , p < .05) and lower RBD levels (<50 AU/mL vs. 1435 AU/mL, p = .02). HaH saved 753 inpatient patient-days with no deaths observed. Hospital admission rates from the HaH programme was 13.6%. Patients who required inpatient care had direct access admission without utilization of emergency department resources.

CONCLUSION

Selected KTRs with COVID-19 infection can be safely managed in a HaH programme; alleviating strain on inpatient and emergency healthcare resources.

Favorable outcomes of COVID-19 in vaccinated hematopoietic stem cell transplant recipients: A single-center experience

INTRODUCTION

A high incidence of mortality and severe COVID-19 infection was reported in hematopoietic stem cell transplant (HSCT) recipients during the early phases of the COVID-19 pandemic; however, outcomes with subsequent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants, such as the omicron variant, have yet to be reported. Additionally, rollout of COVID-19 vaccinations in subsequent pandemic waves may modify COVID-19 disease severity and mortality in this immunocompromised population. We describe COVID-19 outcomes among a highly vaccinated population of HSCT recipients at a single center during successive waves of community transmission arising from the SARS-CoV-2 delta and omicron variants.

METHODS

We retrospectively reviewed medical records of all HSCT recipients at our institution who tested positive for SARS-CoV-2 from May 2021 to May 2022. Descriptive statistics were reported; the chi-square test was utilized to identify factors associated with 90-day all-cause mortality and severity of COVID-19 infection.

RESULTS

Over the 1-year study period, 77 HSCT recipients at our center contracted COVID-19 (43 allogenic; 34 autologous). Twenty-six (33.8%) patients were infected with the SARS-CoV-2 delta variant, while 51 (66.2%) had the SARS-CoV-2 omicron variant. Thirty-nine (50.6%) patients required hospitalization. More than 80% had received prior COVID-19 vaccination (57.1% with two doses, 27.3% with three doses). The majority (90.9%) had mild disease; only one (1.3%) patient required mechanical ventilation. Active hematological disease at time of COVID-19 infection was associated with increased odds of mortality [odds ratio (OR) = 6.90, 95% confidence interval (CI) = 1.20-40]. The 90-day all-cause mortality was 7.8% (six patients). Infection with the omicron variant (vs. delta) was associated with less severe illness (OR = 0.05, 95% CI = 0.01-0.47) and decreased odds of mortality (OR = 0.08, 95% CI = 0.01-0.76). Being on immunosuppression (OR = 5.10, 95% CI = 1.10-23.60) and being unvaccinated at disease onset (OR = 14.76, 95% CI = 2.89-75.4) were associated with greater severity of COVID-19 infection.

CONCLUSION

We observed favorable outcomes with COVID-19 infection in a cohort of vaccinated HSCT patients. The SARS-CoV-2 omicron variant was associated with both less severe illness and decreased odds of mortality. As COVID-19 moves toward endemicity, early access to treatment and encouraging vaccination uptake is crucial in mitigating the challenge of COVID-19 management among HSCT recipients. Surveillance and assessment of clinical outcomes with new SARS-CoV-2 variants also remains important in this immunocompromised population.

Detection rate of MR myelography without intrathecal gadolinium in patients with newly diagnosed spontaneous intracranial hypotension

AIM

To evaluate the detection rate of magnetic resonance (MR) myelography without intrathecal gadolinium for cerebrospinal fluid (CSF) leakage in patients with newly diagnosed spontaneous intracranial hypotension (SIH) and to validate a published scoring system for predicting CSF leakage.

MATERIALS AND METHODS

This retrospective, observational, single-institution study included patients with newly diagnosed SIH between March 2015 and April 2021. Patients were included if they (a) had newly diagnosed SIH and (b) underwent initial brain MR imaging and preprocedural MR myelography with two- and three-dimensional turbo spin-echo sequences. Patients who underwent spine surgery or procedures including epidural injection and acupuncture were excluded. The detection rate was defined as the proportion of patients with a true-positive MR myelography result among all patients with confirmed CSF leakage. The interobserver agreement for the MR myelography results between two radiologists was analysed using weighted kappa statistics.

RESULTS

A total of 136 patients (mean age, 48 years; 70 women) with suspected SIH were included. Of these patients, 120 (88%, 120/136) were confirmed to have CSF leakage. Of the patients with confirmed CSF leakage, 90 (75%, 90/120) had epidural fluid collection. The detection rate of MR myelography for CSF leakage was 88% (105/120). The interobserver agreement between the two readers for detecting CSF leakage (κ = 0.76) or epidural fluid collection (κ = 0.76) on MR myelography was high. Among 24 patients with normal brain MR imaging results, 16 had CSF leakage (67%, 16/24).

CONCLUSIONS

Non-invasive MR myelography without intrathecal gadolinium should be considered to detect CSF leakage in patients with suspected SIH.

Current state of antimicrobial stewardship in organ transplantation in Singapore

BACKGROUND

Antibiotic stewardship programs (ASPs) are well established in the public hospitals in Singapore, but they are not mandatory for transplant programs. Given the positive impact of ASPs in non-organ transplant patients (improved use of broad-spectrum antibiotics, reduced length of stay and lower healthcare costs), stewardship principles are likely to benefit transplant recipients.

METHODS

We reviewed the progress made in ASPs in the Asia Pacific region as well as the progress of our ASP over the last decade since it was established. We also described how stewardship strategies have evolved for the purposes of our transplant program.

RESULTS

Currently, pressing stewardship issues for our transplant program include high antibiotic consumption, as well as the burden, morbidity and mortality associated with drug-resistant bacterial infections. Transplanting the model of stewardship onto a transplant program ignores the intricacies of transplant patients; the bespoke form of stewardship, "handshake stewardship", is more appropriate.

CONCLUSION

To advance the cause of ASP in the transplant unit in Singapore, stakeholder buy-in is key; empowering transplant physicians to be stewardship focused would be more sustainable in the long run. In addition, expanding our diagnostic armamentarium, optimizing existing therapeutics and multi-disciplinary team involvement (including stakeholders from microbiology, infection prevention teams) is vital. This article is protected by copyright. All rights reserved.

inPhocus: Current State and Challenges of Phage Research in Singapore

Bacteriophages and phage-derived proteins are a promising class of antibacterial agents that experience a growing worldwide interest. To map ongoing phage research in Singapore and neighboring countries, Lee Kong Chian School of Medicine, Nanyang Technological University Singapore (NTU) and Yong Loo Lin School of Medicine, National University of Singapore (NUS) recently co-organized a virtual symposium on Bacteriophage and Bacteriophage-Derived Technologies, which was attended by more than 80 participants. Topics were discussed relating to phage life cycles, diversity, the roles of phages in biofilms and the human gut microbiome, engineered phage lysins to combat polymicrobial infections in wounds, and the challenges and prospects of clinical phage therapy. This perspective summarizes major points discussed during the symposium and new perceptions that emerged after the panel discussion.

34. Stemming the Rise in Antibiotic Prescription for Community Acquired Respiratory Infections (ARI) During COVID-19 Pandemic in Singapore General Hospital (SGH)

Background

In early months of COVID-19 pandemic, SGH recorded a year-on-year increase in antibiotic (ABx) use for community acquired acute respiratory infection (CA ARI) from Feb-Apr 2019 (48.7 defined daily doses (DDD)/100 bed-days) to 2020 (50.8 DDD/100 bed-days). To address concerns of misuse, the antibiotic stewardship unit (ASU) expanded prospective audit feedback (PAF) to CA ARI patients admitted to ARI wards, with low procalcitonin (PCT). PAF was conducted on day 2-3 of ABx, on weekdays. Doctors received feedback to stop/modify when ABx was deemed inappropriate. Here, we describe the impact of ASU’s adaptive approach to curb rising ABx use in patients admitted for ARI during COVID-19 pandemic.

Methods

A Pre- & Post-intervention study was conducted. All patients started on ABx (ceftriaxone/co-amoxiclav/piptazo/carbapenems/levofloxacin) for CA ARI & PCT &lt; 0.5µg/L were analysed. Those who died ≤48h of admission; admitted to intensive care; required ABx escalation; &gt;1 infective sites; complex lung infection were excluded. Primary objective was to compare the proportion of ABx stopped ≤4 days (time to final infection diagnosis) Pre (22/3-18/4/20) & Post (21/4-13/7/20).

Results

184 (Pre) & 528 (Post) ABx courses were analysed. ASU audited 51 (Pre) & 380 (Post) courses with the rest discontinued/discharged before review. Patients were largely similar in both periods; a third had low likelihood of bacterial infection (C reactive protein &lt; 30mg/L). In Post, 73 feedback was given to stop ABx (often because symptoms suggested viral/fluid overload) & 18 to switch to oral ABx. 82 (90%) feedback was accepted. No ABx was restarted ≤48h or deaths ≤30 days due to ARI. 1 patient had C. difficile diarrhoea a day after ABx cessation as per ASU feedback.

Proportion of all ABx stopped ≤4 days was higher in Post than Pre [27/184 (15%) vs 152/528 (29%), p&lt; 0.01]. Median duration of therapy of IV ABx was reduced (6.5 vs 3 days, p&lt; 0.01), with corresponding shorter median length of stay (10.5 vs 6 days, p&lt; 0.01).

Conclusion

PAF directly and indirectly reduced ABx duration in patients treated for CA ARI as prescribers become more conscious about stopping ABx when investigations show low likelihood of bacterial infection. ASU must remain agile during pandemics to detect emerging problems and adapt processes to counter early.

Disclosures

All Authors: No reported disclosures

104. Improving Efficiency of Antimicrobial Stewardship Reviews Using Artificial Intelligence Modelling

Background

Antimicrobial stewardship programs (ASP) in hospitals improve antibiotic prescribing, slow antimicrobial resistance, reduce hospitalisation duration, mortality and readmission rates, and save costs. However, the strategy of prospective audit and feedback is laborious. In Singapore General Hospital (SGH), 10 reviews are required to identify 2 inappropriate cases. Limited manpower constraints ASP audits to only about 30% of antibiotics prescribed. This proof-of-concept study explored the feasibility of developing a predictive model to prioritise inappropriate antibiotic prescriptions for ASP review.

Methods

ASP-audited adult pneumonia patients from January 2016 to December 2018 in SGH were included. Patient data e.g., demographics, allergies, past medical history, and relevant laboratory investigations at each antibiotic use episode were extracted from electronic medical records and re-assembled through linking for analysis. Ground truth for model training was based on ASP-defined appropriateness for each encounter. The dataset was split into 80% and 20% for training and testing respectively. Three modelling techniques, XGBoost, decision tree and logistic regression, were assessed for their relative performance in terms of precision, sensitivity and specificity.

Results

There were 12471 unique patient encounters. Training was done on 10459 encounters and 39 data elements were included. When tested on 2012 encounters, the logistic regression model performed the best (86.7% sensitivity, 71.4% specificity). The model correctly classified 1377 out of 1388 (99.2%) encounters as “appropriate” (do not require ASP intervention). 624 antibiotic use encounters were classified as “inappropriate”, of which only 72 were truly inappropriate (positive predictive value for ASP intervention, PPV 11.5%). The low PPV was likely due to inadequate representation of “inappropriate” cases in the training dataset (4.1%). Applying this model would prioritise the number of immediate ASP reviews needed to identify cases for intervention by two-thirds, from 2012 to 624 (Figure 1).

Figure 1. Illustration of AI benefits in ASP

Conclusion

ASPs can leverage on machine learning capabilities to improve audit efficiency. This can increase ASP’s productivity and staff’s job satisfaction as they are freed up to perform other work.

Disclosures

All Authors: No reported disclosures

815. Short-Course vs. Extended-Course Perioperative Antibiotic Prophylaxis in Patients Receiving Unilateral Primary Total Knee Arthroplasty

Background

International guidelines recommend up to 24 hours of perioperative antibiotic prophylaxis (AP) in joint replacement procedures. However, some observational studies support AP beyond 24 hours for the prevention of surgical site infections (SSI) and prosthetic joint infections (PJI), and this practice is also observed in our institution. This study aims to evaluate the incidence of SSI and PJI in patients receiving short- vs extended-course AP after unilateral primary total knee arthroplasty (TKA) at our center.

Methods

This was a retrospective cohort study of patients who underwent elective unilateral primary TKA from October to December 2019 at Singapore General Hospital. Patients were excluded if they received antibiotics for reasons other than post-operative AP or underwent other procedures in addition to unilateral primary TKA. Data was collected from electronic medical records and patients who received a short-course of AP (≤24 hours) were compared with patients who received an extended-course of AP. Primary outcomes were 30-day SSI and 30-day PJI rates. Secondary outcome was the impact of duration of AP on length of stay. Statistical analysis was performed using SPSS software version 20.

Results

There were 394 patients included in the study. 247 received short-course and 147 received extended-course AP. There were no differences in demographics (Table 1). Amongst those who received extended-course AP, median duration was 7 (IQR 4, 8) days, during which 119 (81.0%) patients switched from intravenous to oral route of antibiotics. Between the short- and extended-course arms, there were no differences observed in 30-day SSI (6.9% vs 6.1%, p=0.769) or PJI rates (0.4% vs 0.7%, p=0.999). However, extended-course AP was associated with a longer median length of stay (4 [IQR 3, 6] vs 5 [IQR 4, 7] days, p=0.001). In a subgroup analysis of 106 diabetic patients, there were no differences in 30-day SSI rates (12.3% vs 9.8%, p=0.763) and 30-day PJI rates (0% vs 2.4%, p=0.387) between both groups.

Conclusion

In this single center study, short-course AP in elective TKA was safe and effective. Extending AP did not reduce SSI or PJI rates, even in diabetic patients. In addition, extending AP was associated with increased length of stay, which translates to higher healthcare costs.

Disclosures

All Authors: No reported disclosures

141. Effectiveness of a Multipronged Approach to Improve Prophylactic Antibiotic Prescribing in Patients Undergoing Trans-Arterial Chemoembolization

Background

In our institution, the significant use of broad-spectrum antibiotics for antibiotic prophylaxis (AP) in trans-arterial chemoembolization (TACE) was operator dependent and not evidence based. Hence, an AP guideline was developed with the Department of Vascular and Interventional Radiology and launched in May 2019, following department roadshows and creation of user-friendly electronic AP order sets. We analyzed the effectiveness and outcomes of our multipronged approach towards improving the standardization of AP prescribing.

Methods

This was a retrospective study of TACE procedures from November 2018 to March 2020, pre and post guideline implementation (Figure 1). Single IV cefazolin 2g dose (or IV clindamycin 600mg in the setting of β-lactam allergy) before TACE in patients with an uncompromised sphincter of Oddi was recommended. Patients with active infections prior to TACE were excluded. AP was deemed inappropriate if it deviated from guidelines (antibiotic choice and/or duration). Primary outcome was AP appropriateness and 30-day TACE related infections.

Figure 1. Timeline of our multipronged approach

Results

Seventy patients were included. There were no differences in baseline demographics pre and post implementation (Table 1). Following guideline implementation, there was a significant improvement in AP used for TACE. AP appropriateness pre-implementation and post-implementation was 14/31 (45.2%) and 37/39 (94.9%) respectively (p< 0.001). Guideline compliant antibiotics were selected more frequently (14 [45.2%] vs 38 [97.4%], p< 0.001), and more patients received single dose AP (22 [71.0%] vs 38 [97.4%], p=0.004). Of the 18 patients who did not receive guideline recommended AP, 16 (88.9%) received IV ceftriaxone and metronidazole, 1 (5.6%) IV amoxicillin/clavulanic acid, and 1 (5.6%) IV ciprofloxacin. Ten patients received a prolonged course of AP with a median duration of 6 days (IQR 4.3, 6.5). There were no significant differences in 30-day TACE related infections (1 [3.2%] vs 2 [5.1%], p=1.000) and 30-day mortality (1 [3.2%] vs 1 [2.6%], p=1.000). No patient had surgical site skin infection.

Conclusion

Our multipronged approach improved AP prescribing in patients undergoing TACE. Single dose IV cefazolin prophylaxis for TACE did not compromise safety outcomes in the post implementation review.

Disclosures

All Authors: No reported disclosures

Hospital Pharmacists and Antimicrobial Stewardship: A Qualitative Analysis

Antimicrobial stewardship programmes (ASPs) in hospitals are predominantly led by specific ASP physicians and pharmacists. Limited studies have been conducted to appreciate non-ASP-trained hospital pharmacists' perspectives on their roles in antimicrobial stewardship. Focus group discussions (FGDs) were conducted with 74 pharmacists, purposively sampled from the 3 largest acute-care public hospitals in Singapore, to explore facilitators and barriers faced by them in antimicrobial stewardship. Applied thematic analysis was conducted and codes were categorised using the social-ecological model (SEM). At the intrapersonal level, pharmacists identified themselves as reviewers for drug safety before dispensing, confining to a restricted advisory role due to lack of clinical knowledge, experience, and empowerment to contribute actively to physicians' prescribing decisions. At the interpersonal level, pharmacists expressed difficulties conveying their opinions and recommendations on antibiotic therapy to physicians despite frequent communications, but they assumed critical roles as educators for patients and their caregivers on proper antibiotic use. At the organisational level, in-house antibiotic guidelines supported pharmacists' antibiotic interventions and recommendations. At the community level, pharmacists were motivated to improve low public awareness and knowledge on antibiotic use and antimicrobial resistance. These findings provide important insights into the gaps to be addressed in order to harness the untapped potential of hospital pharmacists and fully engage them in antimicrobial stewardship.

Impact of COVID-19 on TB epidemiology in South Korea

SETTING: Five referral hospitals, South Korea.OBJECTIVE: To assess epidemiological changes in TB before and during the COVID-19 pandemic.DESIGN: This was a multicentre cohort study of 3,969 patients diagnosed with TB.RESULTS: We analysed 3,453 patients diagnosed with TB prior to the COVID-19 pandemic (January 2016-February 2020) and 516 during the pandemic (March-November 2020). During the pandemic, the number of patients visits declined by 15% from the previous 4-year average, and the number of patients diagnosed with TB decreased by 17%. Patients diagnosed during the pandemic were older than those diagnosed before the pandemic (mean age, 60.2 vs. 56.6 years, P < 0.001). The proportion of patients to have primary TB at a younger age (births after 1980) among those diagnosed with TB was significantly lower during the pandemic than before (17.8% in 2020 vs. 23.5% in 2016, 24.0% in 2017, 22.5% in 2018, 23.5% in 2019; P = 0.005).CONCLUSIONS: The COVID-19 pandemic resulted in a reduction in the number of visits to respiratory departments, leading to fewer patients being diagnosed with TB. However, our results suggest that universal personal preventive measures help to suppress TB transmission in regions with intermediate TB burden.

Antibiotic stewardship program (ASP) in palliative care: antibiotics, to give or not to give

Antimicrobial therapy in terminally ill patients remains controversial as goals of care tend to be focused on optimizing comfort. International guidelines recommend for antibiotic stewardship program (ASP) involvement in antibiotic decisions in palliative patients. The primary objective was to evaluate the clinical impact of ASP interventions made to stop broad-spectrum intravenous antibiotics in terminally ill patients. This was a retrospective chart review of 459 terminally ill patients in Singapore General Hospital audited by ASP between December 2010 and December 2018. Antibiotic duration, time-to-terminal discharge for end-of-life care, time-to-mortality, and mortality rates of patients with antibiotics ceased or continued upon ASP recommendations were compared. A total of 283 and 176 antibiotic courses were ceased and continued post-intervention, respectively. The intervention acceptance rate was 61.7%. The 7-day mortality rate (47.3% vs 61.9%, p = 0.003) was lower in the ceased group, while 30-day mortality rate (76.0% vs 81.2%, p = 0.203) and time-to-mortality post-intervention (3 [0-24] vs 2 [0-27] days, p = 0.066) did not differ between the ceased and continued groups. After excluding the 57 patients who had antibiotics continued until death within 48 h of intervention, only time-to-mortality post-intervention was statistically significantly shorter in the ceased group (3 [0-24] vs 4 [0-27], p < 0.001). Of the 131 terminally discharged patients, antibiotic duration (4 [0-17] vs 6.5 [1-14] days, p = 0.001) and time-to-terminal discharge post-intervention (6 [0-74] vs 10.5 [3-63] days, p = 0.001) were shorter in the ceased group. Antibiotic cessation in terminally ill patients was safe, and was associated with a significantly shorter time-to-terminal discharge.

A single-centre observational study comparing the impact of different cytomegalovirus prophylaxis strategies on cytomegalovirus infections in kidney transplant recipients

Background/objective:

Prevention of cytomegalovirus (CMV) infection is an important component of post kidney transplant care. We aimed to evaluate the impact of two different CMV prophylaxis protocols on the epidemiology and outcomes of CMV infections at our centre.

Methods:

This is a single-centre retrospective before/after observational study. Kidney transplant recipients who received Protocol 1, a valacyclovir- or valganciclovir-based regimen prescribed for one to three months based on the CMV risk status between 2004 and 2008, were compared to those who received Protocol 2, a valganciclovir-based regimen prescribed for three months and six months for those at moderate and high risk, respectively, between 2010 and 2014. The impact of different prophylaxis regimens on the incidence of CMV infections, disease, recurrent infections and onset of CMV infection at 24 months were reviewed.

Results:

There were 192 patients included; 106 patients received Protocol 1, 86 received Protocol 2. At 24 months, the incidence of CMV infection was 53.8% and 55.8% in Protocols 1 and 2, respectively ( p=0.884). The incidence rates of CMV disease and recurrent CMV infections were higher in Protocol 1, but this was not statistically significant. The median time to first CMV infection was significantly shorter in patients who received Protocol 1: 132 days (interquartile range (IQR) 125–139 days) versus 185 days (IQR 178–192 days), p=0.001. Both prophylaxis protocols were well tolerated.

Conclusion:

The incidence of CMV infection was similar in both protocols. Where valganciclovir is not available, valacyclovir may be considered over no prophylaxis. Post-prophylaxis CMV infections are not uncommon, and vigilance for it should be advocated.

Aortic endograft infection secondary to Burkholderia pseudomallei: A case report and review of the literature

Aortic graft infection is a rare complication after endovascular aneurysm repair that is usually caused by gram-positive organisms such as Staphylococcus spp or gram-negative organisms such as Enterobacteriaceae or Salmonella spp. We have presented a unique case of a patient with acute graft infection secondary to Burkholderia pseudomallei. Because treatment of B. pseudomallei infections is challenging owing to its inherent resistance to multiple antibiotics, we have proposed an approach for managing similar cases in the future. Lifestyle advice on avoiding soil exposure in the postoperative period after endovascular aneurysm repair might be an important preventative measure in endemic regions.

Waitlisted Transplant Candidates' Attitudes and Concerns Toward Transplantation During COVID-19

Background

In solid organ transplant (SOT) and hematopoietic stem cell transplant (HSCT) recipients, coronavirus disease 2019 (COVID-19) can contribute to a severe clinical course and an increased risk of death. Thus, patients awaiting a SOT or HSCT face the dilemma of choosing between a life-saving treatment that presents a significant threat of COVID-19 and the risk of waitlist dropout, progression of disease, or mortality. The lack of established literature on COVID-19 complicates the issue as patients, particularly those with inadequate health literacy, may not have the resources needed to navigate these decisions.

Material/Methods

We conducted a standardized phone survey of patients awaiting SOT or HSCT to assess the prevalence of inadequate health literacy and attitudes toward transplant during the COVID-19 pandemic.

Results

Seventy-one patients completed the survey, with a response rate of 84.5%. Regardless of health literacy, most waitlisted candidates recognized that the current pandemic is a serious situation affecting their care and that COVID-19 poses a significant risk to their health. Despite the increased risks, most patients reported they would choose immediate transplantation if there was no foreseeable end to the pandemic, and especially if the medical urgency did not permit further delay. There were no differences in responses across the patient waitlist groups for heart, kidney, liver, and stem cell transplant.

Conclusions

These findings can help transplant centers decide how transplantation services should proceed during this pandemic and can be used to educate patients and guide discussions about informed consent for transplant during the COVID-19 pandemic.

Performance of Population Pharmacokinetic Models in Predicting Polymyxin B Exposures

Polymyxin B is the last line of defense in treating multidrug-resistant gram-negative bacterial infections. Dosing of polymyxin B is currently based on total body weight, and a substantial intersubject variability has been reported. We evaluated the performance of different population pharmacokinetic models to predict polymyxin B exposures observed in individual patients. In a prospective observational study, standard dosing (mean 2.5 mg/kg daily) was administered in 13 adult patients. Serial blood samples were obtained at steady state, and plasma polymyxin B concentrations were determined by a validated liquid chromatography tandem mass spectrometry (LC-MS/MS) method. The best-fit estimates of clearance and daily doses were used to derive the observed area under the curve (AUC) in concentration–time profiles. For comparison, 5 different population pharmacokinetic models of polymyxin B were conditioned using patient-specific dosing and demographic (if applicable) variables to predict polymyxin B AUC of the same patient. The predictive performance of the models was assessed by the coefficient of correlation, bias, and precision. The correlations between observed and predicted AUC in all 5 models examined were poor (r² < 0.2). Nonetheless, the models were reasonable in capturing AUC variability in the patient population. Therapeutic drug monitoring currently remains the only viable approach to individualized dosing.

An unusual case of Scedosporium apiospermum fungaemia in an immunocompetent patient with a left ventricular assist device and an implantable cardiac device

Left ventricular assist device (LVAD)-related infections are a leading cause of morbidity and mortality, with fungal infections being particularly difficult to manage. We report a case of an immunocompetent 39-year-old male with an LVAD and an implantable cardiac device (ICD) who developed fatal Scedosporium apiospermum fungaemia. To the best of our knowledge, this is the first reported case of LVAD-related S. apiospermum fungaemia.

Impact of formulary interventions on the minimum inhibitory concentration of methicillin-resistant Staphylococcus aureus to mupirocin, chlorhexidine, and octenidine in a Singapore tertiary institution

Methicillin-resistant Staphylococcus aureus (MRSA) decolonization is an effective measure to prevent clinical infection but resistance is a concern. We aim to evaluate the impact of mupirocin (MUP) ointment formulary removal, plateauing use of chlorhexidine gluconate (CHG), and hospital-wide introduction of octenidine (OCT)-based products on the minimum inhibitory concentration (MIC) of MRSA to MUP, CHG, and OCT in our hospital. A prevalence study was conducted at three time points (TP) on consecutive MRSA screening isolates to evaluate for their MICs to MUP, CHG, and OCT using broth microdilution sensititre plates and detection of the ileS-2 gene encoding high-level MUP resistance in 2013 (pre-intervention TP1; n = 160), 2016 (early post-intervention TP2; n = 99) and 2017 (late post-intervention TP3; n = 76). Statistical analyses were performed using Chi square test with reference from TP1. There was a significant improvement in MUP susceptibility (MIC < 4 mcg/ml) from 71.9% (TP1) to 86.9% (TP2; p = 0.006) to 88.2% (TP3; p = 0.007). The prevalence of MUP high-level resistance (MIC > 256 mcg/ml) reduced from 25.0% (TP1) to 12.1% (TP2; p = 0.014) to 5.3% (TP3; p = 0.001). Likewise, the prevalence of isolates harboring the ileS-2 gene decreased from 28.1% (TP1) to 18.2% (TP2; p = 0.072) to 9.2% (TP3; p = 0.002). OCT MIC range remains stable at 0.5 to 1 mcg/ml across all three TPs. The proportion of isolates with reduced CHG susceptibility (MIC ≥ 4 mcg/ml) increased over the three TPs from 23.1 to 27.2% (p = 0.45) to 42.1% (p = 0.003). Active formulary regulations have an impact on the resistance profile of MRSA and can be used as a strategy to preserve the MRSA decolonization armamentarium.

Sex-specific association of urate and levodopa-induced dyskinesia in Parkinson's disease

BACKGROUND AND PURPOSE

As a major antioxidant, uric acid (UA) is known to be associated with the clinical progression of Parkinson's disease (PD). This study investigated whether baseline UA levels are associated with the risk for levodopa-induced dyskinesia (LID) in PD in a sex-dependent manner.

METHODS

In all, 152 patients with de novo PD (78 males and 74 females) who were followed up for >2 years were enrolled. The effect of baseline serum UA levels on LID-free survival was assessed by Cox regression, separately for sex, whilst being adjusted for potential confounding factors. The optimal UA level cut-off value to determine the high-risk group for LID was set using Contal and O'Quigley's method.

RESULTS

Levodopa-induced dyskinesia developed in 23 (29.5%) male patients and 30 (40.5%) female patients. Cox regression showed a significant interaction between UA level and sex. Higher UA levels were associated with a higher risk for LID in male PD patients (hazard ratio 1.380; 95% confidence interval 1.038-1.835; P = 0.027), although this relationship was not observed in female PD patients. The optimal UA level cut-off for LID in male PD was 7.2 mg/dl, and the high UA group had a 5.7-fold higher risk of developing LID than the low UA group.

CONCLUSIONS

Contrary to a presumptive beneficial role of UA, the present study demonstrated that higher UA levels are associated with increased risk of LID occurrence in male patients with PD, suggesting a sex-dependent role of UA in LID.

Practical Considerations for Solid Organ Transplantation During the COVID-19 Global Outbreak: The Experience from Singapore

The current coronavirus disease 2019 (COVID-19) pandemic has not only caused global social disruptions but has also put tremendous strain on healthcare systems worldwide. With all attention and significant effort diverted to containing and managing the COVID-19 outbreak (and understandably so), essential medical services such as transplant services are likely to be affected. Closure of transplant programs in an outbreak caused by a highly transmissible novel pathogen may be inevitable owing to patient safety. Yet program closure is not without harm; patients on the transplant waitlist may die before the program reopens. By adopting a tiered approach based on outbreak disease alert levels, and having hospital guidelines based on the best available evidence, life-saving transplants can still be safely performed. We performed a lung transplant and a liver transplant successfully during the COVID-19 era. We present our guidelines and experience on managing the transplant service as well as the selection and management of donors and recipients. We also discuss clinical dilemmas in the management COVID-19 in the posttransplant recipient.

Cognitive anosognosia is associated with frontal dysfunction and lower depression in Parkinson's disease

BACKGROUND AND PURPOSE

Anosognosia refers to a deficit of self-awareness or impaired insight for cognitive and behavioral problems. Cognitive anosognosia was explored in de novo patients with Parkinson's disease (PD) and its relationship to cognitive function and neuropsychiatric symptoms was investigated.

METHODS

The cross-sectional study enrolled 340 drug-naïve patients with PD. According to the presence of mild cognitive impairment (MCI) and subjective cognitive complaint, patients were classified as patients with cognitive anosognosia (PD-CA, n = 74), with normal cognitive recognition (PD-NR, n = 184) or with cognitive underestimation (PD-CU, n = 82). After controlling for covariates, cognitive performance and neuropsychiatric symptoms were compared between the PD groups.

RESULTS

Cognitive anosognosia was found in 21.8% of patients with de novo PD. The PD-CA group showed poorer performance in all cognitive domains except for attention. Amongst PD patients with MCI, those with cognitive anosognosia showed lower composite z-scores in the Stroop color reading test than those without. The Beck Depression Inventory score in the PD-NR group was lower than that in the PD-CU group and higher than that in the PD-CA group. The Cognitive Complaints Interview score mediated the association between cognitive anosognosia and Beck Depression Inventory score.

CONCLUSIONS

Cognitive anosognosia in PD was associated with greater frontal dysfunction and lower depression. Since cognitive anosognosia has a harmful impact on PD patients and their caregivers due to overestimation of their abilities in everyday life, early identification of cognitive anosognosia in PD is important in management and prognosis.

1764. Use of Intravesical BCG for Treatment of Bladder Cancer in a Renal Transplant Recipient, with Subsequent Resolution of Chronic BK Viremia

Background

BK virus-induced nephropathy in renal transplantation is well recognized but its oncogenic potential is less appreciated.

Methods

We report a case of high-grade urothelial tumor in a renal transplant recipient with chronic BK viremia in the absence of BK nephropathy successfully treated with intravesical Bacillus Calmette-Guerin (BCG) instillation. Following BCG therapy, there was also spontaneous clearance of BK viremia.

Results

In July 2011, Mr. LYY, a 57-year-old Chinese man with end-stage renal failure secondary to chronic glomerulonephritis underwent uncomplicated deceased donor renal transplantation. One year later, he developed persistent high-level BK viremia despite reduction in immunosuppression. He was also treated with a course of ciprofloxacin from January to October 2013, and intravenous immunoglobulin (IVIG) in February 2013, but high-level BK viremia persisted. In spite of this, his graft function was preserved. He was subsequently placed on BK surveillance alone. Chronic BK viremia persisted for the next 5 years with stable graft function. See Figure 1. In February 2018, an incidental urinary bladder nodule was picked up on computed tomography (CT) scan performed for evaluation of urosepsis. Follow-up flexible cystoscopy in May 2018 showed a 1.5 cm papillary tumor over the left superior bladder wall. Transurethral resection of bladder tumor (TURBT) was performed and histopathological examination revealed high-grade papillary urothelial carcinoma. In addition, the biopsy specimen was stained positive for SV40, suggesting the possible association between chronic BK virus replication in the bladder and oncogenesis. Relook TURBT in July 2018 revealed a persistent erythematous patch over the posterior bladder wall. Given the cystoscopic findings, Mr. LYY received a weekly instillation of intravesical BCG for 6 weeks. He tolerated the intravesical BCG treatment with no local or systemic complications. Interestingly, his serum BK viral loads dropped below lower limits of detection thereafter and continued to remain so for the next 4 months.

Conclusion

We postulate that the intravesical BCG therapy triggered an immune response that targeted not only the tumor but also the BK virus infection, resulting in successful clearance of chronic BK viremia.

Disclosures

All authors: No reported disclosures.

564. A Five-Year Evolutionary Study of the Minimum Inhibitory Concentrations of Methicillin-resistant Staphylococcus aureus to Mupirocin, Chlorhexidine, and Octenidine in a Singaporean Tertiary Institution

Background

Methicillin-resistant Staphylococcus aureus (MRSA) is a common cause of healthcare-associated infection. Eradication of MRSA carriage reduces clinical infection and prevents transmission. In Singapore General Hospital, a series of hospital-wide measures were instituted over three years (Figure 1) to reduce mupirocin (MUP) resistance, and to decrease the bioburden of MRSA colonization amongst inpatients using octenidine (OCT)-based products.

Methods

A prevalence study was conducted at three time points (TPs) on consecutive MRSA screening isolates to evaluate for their minimum inhibitory concentrations (MICs) to CHG, OCT and MUP using broth microdilution sensitive plates and the presence of the ileS-2 gene, in 2013 (pre-intervention TP, TP1; n = 160), 2016 (early post-intervention TP, TP2; n = 99) and 2017 (late post-intervention TP, TP3; n = 76). Statistical analyses were performed using the Chi-square test with reference from TP1.

Results

A significant improvement in MUP susceptibility by MIC (256 µg/mL) and ileS-2 testing reduced from 25.0% (TP1) to 12.1% (TP2; P = 0.014) to 5.3% (TP3; P = 0.001) and 30.0% (TP1) to 18.2% (TP2; P = 0.036) to 9.2% (TP3; P = 0.001), respectively. OCT MIC range remained stable at 0.5 to 1 across all three TPs. The number of isolates with reduced CHG susceptibility (MIC ≥4 mg/L) increased over the three TPs from 23.1% to 27.2% (P = 0.45) to 42.1% (P = 0.003), despite decreasing CHG prescription.

Conclusion

A restrictive MUP usage policy can improve MUP susceptibility amongst MRSA isolates over time. Widespread OCT use did not appear to result in a rise of OCT MIC over the intervention period. Although the clinical significance of reduced susceptibility to CHG remains uncertain, this worrying trend in our institution deserves further studies to better understand mechanisms of CHG resistance.

Disclosures

All authors: No reported disclosures.

Effects of Alzheimer's disease and Lewy body disease on subcortical atrophy

BACKGROUND AND PURPOSE

Subcortical structures are affected by neurodegeneration in Alzheimer's disease (AD) and Lewy body disease (LBD). Although the co-occurrence of AD and LBD pathologies and their possible interaction have been reported, the effect of AD and LBD on subcortical structures remains unknown. The effects of AD and LBD on subcortical atrophy and their relationship with cognitive dysfunction were investigated.

METHODS

The cross-sectional study recruited 42 patients with pure AD related cognitive impairment (ADCI), 30 patients with pure LBD related cognitive impairment (LBCI), 58 patients with mixed ADCI and LBCI, and 29 normal subjects. A general linear model was used to compare subcortical volume and shape amongst the groups, to investigate the independent and interaction effects of ADCI and LBCI on subcortical shape and volume, and to analyze the relationship between subcortical volume and cognitive dysfunction in each group.

RESULTS

Alzheimer's disease related cognitive impairment and LBCI were independently associated with subcortical atrophies in the hippocampus and amygdala and in the hippocampus and putamen respectively, but their interaction effect was not significant. Compared to the control group, the pure LBCI group exhibited additional local atrophies in the amygdala, caudate and thalamus. Subcortical atrophies correlated differently with cognitive dysfunction according to the underlying causes of cognitive dysfunction.

CONCLUSIONS

The patterns of subcortical atrophies and their correlation with cognitive dysfunction differ according to the underlying AD, LBD or concomitant AD and LBD.

Clinical relevance of amnestic versus non-amnestic mild cognitive impairment subtyping in Parkinson's disease

BACKGROUND AND PURPOSE

To clarify whether subtyping of amnestic and non-amnestic mild cognitive impairment (MCI) is clinically relevant in Parkinson's disease (PD) by analyzing patterns of neuroimaging and longitudinal cognitive changes.

METHODS

We performed comparative analyses of cortical thickness, hippocampal volume, white matter integrity and resting-state functional connectivity between the patients with de-novo PD with amnestic MCI (PD-aMCI) (n = 50) and non-amnestic MCI (PD-naMCI) (n = 50) subtypes. Additionally, we assessed the longitudinal rate of cognitive decline in each cognitive domain over time and the rate of dementia conversion in patients with de-novo PD-aMCI (n = 125) and PD-naMCI (n = 61).

RESULTS

The demographic data showed that scores in memory domains were lower in the PD-aMCI group compared with the PD-naMCI group. There were no significant differences in cortical thickness, hippocampal volume and white matter integrity between the two groups, although the PD-aMCI group exhibited more cortical thinning and hippocampal atrophy relative to the control group. The PD-aMCI group exhibited increased functional connectivity in the left posterior parietal region with the salience network relative to the PD-naMCI group. The longitudinal cognitive assessment demonstrated that patients with PD-aMCI exhibited a more rapid cognitive decline in frontal/executive function than those with PD-naMCI (P = 0.022). In addition, the PD-aMCI group had a higher risk of dementia conversion than the PD-naMCI group.

CONCLUSIONS

This study suggests that the designation of PD-MCI subtypes based on memory function would highlight the heterogeneity of functional correlates as well as the longitudinal cognitive prognosis.

Recurrent trichosporonosis with central nervous system involvement in an allogeneic hematopoietic stem cell transplant recipient

Trichosporon is an ubiquitous yeast that has emerged as an opportunistic pathogen in the immunocompromised host. We describe a case of invasive trichosporonosis in an allogeneic hematopoietic stem cell transplant (allo-HSCT) recipient while on caspofungin antifungal prophylaxis. She developed disseminated trichosporonosis in the pre-engraftment period and was successfully treated with voriconazole. She later developed 2 further episodes of invasive trichosporonosis involving the central nervous system. This case highlights the challenges of managing trichosporonosis in allo-HSCT recipients and suggests the need for lifelong therapy in some patients.

Malaria in a tertiary hospital in Singapore--clinical presentation, treatment and outcome: an eleven year retrospective review

BACKGROUND

Malaria remains a global health threat and poses significant health risks even in non-endemic regions like Singapore.

METHODS

A retrospective analysis of 214 patients with smear-positive malaria treated at Singapore General Hospital (SGH) between year 2000 and 2010.

RESULTS

One hundred and sixty-seven (78%) patients were male; median age was 35 y (range, 25–52 y). Sixty-four (41%) patients had past history of treated malaria. Seven (4.9%) patients did not travel out of Singapore. One hundred and twenty-seven (76.5%) cases of malaria were acquired in Southeast Asia (SEA) and the Indian subcontinent. There were 127 (59.3%) Plasmodium vivax, 83 (38.8%) Plasmodium falciparum, 1 (0.3%) Plasmodium malariae and 3 (1.4%) mixed infections. Fever was the most common symptom and thrombocytopaenia was the most common laboratory finding. There were 43 severe and 171 uncomplicated cases of malaria, including 8 severe P. vivax cases. Those with severe malaria were older, stayed longer in hospital, had a higher percentage parasitaemia and took longer to clear the parasite. The diagnosis of malaria was suspected at the first contact with healthcare provider in 194 (91.9%) cases. Sixty-one (85.9%) patients with P. falciparum infection received combination anti-malarial therapy and 109 (98.2%) of patients with P. vivax received primaquine for hypnozoite clearance in combination with schizontocidal agent. All the patients survived.

CONCLUSION

In this study, P. vivax was the most common cause of malaria. Severe P. vivax was not uncommon. Cryptic transmission of malaria exists, highlighting the importance of continued vigilance, malaria surveillance and vector control. Early recognition of malaria improved the overall outcome.

Cerebral Microbleeds in Patients with Dementia with Lewy Bodies and Parkinson Disease Dementia

BACKGROUND AND PURPOSE

The burden of amyloid β is greater in patients with dementia with Lewy bodies than in those with Parkinson disease dementia, and an increased amyloid β load is closely related to a higher incidence of cerebral microbleeds. Here, we investigated the prevalence and topography of cerebral microbleeds in patients with dementia with Lewy bodies and those with Parkinson disease dementia to examine whether cerebral microbleeds are more prevalent in patients with dementia with Lewy bodies than in those with Parkinson disease dementia.

MATERIALS AND METHODS

The study population consisted of 42 patients with dementia with Lewy bodies, 88 patients with Parkinson disease dementia, and 35 controls who underwent brain MR imaging with gradient recalled-echo. Cerebral microbleeds were classified as deep, lobar, or infratentorial.

RESULTS

The frequency of cerebral microbleeds was significantly greater in patients with dementia with Lewy bodies (45.2%) than in those with Parkinson disease dementia (26.1%) or in healthy controls (17.1%; P = .017). Lobar cerebral microbleeds were observed more frequently in the dementia with Lewy bodies group (40.5%) than in the Parkinson disease dementia (17%; P = .004) or healthy control (8.6%; P = .001) group, whereas the frequencies of deep and infratentorial cerebral microbleeds did not differ among the 3 groups. Logistic regression analyses revealed that, compared with the healthy control group, the dementia with Lewy bodies group was significantly associated with the presence of lobar cerebral microbleeds after adjusting for age, sex, nonlobar cerebral microbleeds, white matter hyperintensities, and other vascular risk factors (odds ratio, 4.39 [95% CI, 1.27-15.25]). However, compared with the healthy control group, the Parkinson disease dementia group was not significantly associated with lobar cerebral microbleeds.

CONCLUSIONS

This study showed that patients with dementia with Lewy bodies had a greater burden of cerebral microbleeds and exhibited a lobar predominance of cerebral microbleeds than did patients with Parkinson disease dementia.

Debate on MERS-CoV respiratory precautions: surgical mask or N95 respirators?

Since the emergence of Middle East respiratory syndrome coronavirus (MERS-CoV) in mid-2012, there has been controversy over the respiratory precaution recommendations in different guidelines from various international bodies. Our understanding of MERS-CoV is still evolving. Current recommendations on infection control practices are heavily influenced by the lessons learnt from severe acute respiratory syndrome. A debate on respiratory precautions for MERS-CoV was organised by Infection Control Association (Singapore) and the Society of Infectious Disease (Singapore). We herein discuss and present the evidence for surgical masks for the protection of healthcare workers from MERS-CoV.

Waveform analysis of tremor may help to differentiate Parkinson's disease from drug-induced parkinsonism

In this study, we analyzed the waveform characteristics of resting tremor by accelerometer recordings in patients with drug-induced parkinsonism (DIP) and Parkinson's disease (PD). We prospectively recruited 12 patients with tremulous PD and 12 patients with DIP presenting with resting tremor. Tremor was recorded from the more affected side and was recorded twice for a 60 s period in each patient. Peak frequency, amplitude and all harmonic peaks were obtained, and the asymmetry of the decay of the autocorrelation function, third momentum and time-reversal invariance were also computed using a mathematical algorithm. Among the parameters used in the waveform analysis, the harmonic ratio, time-reversal invariance and asymmetric decay of the autocorrelation function were different between PD and DIP at a statistically significant level (all p < 0.01). The total harmonic peak power and third momentum in the time series were not significantly different. The clinical characteristics of DIP patients may be similar to those of PD patients in some cases, which makes the clinical differentiation between DIP and PD challenging. Our study shows that the identification of parameters reflecting waveform asymmetry might be helpful in differentiating between DIP and PD.

Sensory characteristics and cross-cultural consumer acceptability of Bulgogi (Korean traditional barbecued beef)

Bulgogi (Korean traditional barbecued beef) is the most well-known Korean food to foreigners. There are, however, few studies on its sensory characteristics and consumer acceptability. This study was performed to identify the sensory attributes of Bulgogi samples prepared with different formulation and to compare the consumer acceptability in Korea and the United States. Bulgogi samples were prepared with varying levels of sugar and soy sauce with/without garlic or sesame oil. Descriptive analysis was conducted by 8 trained panelists. In consumer tests, 42 consumers in Seoul, Korea, 53 consumers in Davis (Calif., U.S.A.), and 39 consumers in St. Paul (Minn., U.S.A.) participated. Higher levels of sugar and soy sauce (SSS) significantly increased sweetness, saltiness, MSG taste, and soy sauce odor/flavor compared to the control made with the standard formula (CON). Elimination of sesame oil (ESO) significantly decreased sesame oil odor/flavor and oiliness, but increased green onion flavor. Elimination of garlic (EGC) significantly increased grilled beef odor/flavor, sesame oil odor/flavor, and oiliness, but decreased intensities of all the other attributes except bitterness. The consumers in Korea and the United States rated their overall liking for all samples similarly, preferring SSS to CON, EGC, and ESO. However Korean consumers seemed to detect the differences caused by formulation changes better than the U.S. consumers and these perceived differences seemed to impact the hedonic and the just-about-right ratings. Increase in soy sauce and sugar increased both Korean and the U.S. consumers' acceptability of Bulgogi, whereas eliminating garlic did not influence the consumer acceptability despite of its significant impact on sensory attributes.

PRACTICAL APPLICATION

The food industry is increasingly interested in ethnic foods that satisfy sophisticated appetite of today's consumers. Korean cuisine is recently gaining popularity and perceived as "adventurous and spicy," appealing to researchers and marketers in the food industry worldwide. However, it is not easy to develop a new product based on ethnic cuisine because nonsensory factors, such as food neophobia and openness to new culture, can evoke adverse responses from the consumers. A systematic sensory approach can guide the product development by identifying both sensory and nonsensory factors affecting consumer acceptability. This study investigated sensory attributes of Bulgogi (Korean traditional barbecued beef), one of the most famous Korean foods, and compared consumer acceptability between Korea and the United States. The outcomes of this study, such as flavor profiles, consumer responses, evaluation procedure, and approaches taken for cross-cultural comparison, will provide the food industries with valuable information that will help to develop effective strategies for commercializing ethnic foods including recipe development for Bulgogi marinades.

VDUP1 potentiates Ras-mediated angiogenesis via ROS production in endothelial cells

Vitamin D3 up-regulated protein 1 (VDUP1) is a tumor suppressor of which expression is reduced in a variety of cancer cells, and enforced expression inhibits the tumor cell proliferation. It inhibits the activity of thioredoxin, thus contributing cellular ROS generation. Since ROS is a critical factor for angiogenesis, we investigated the role of VDUP1 in angiogenesis and endothelial proliferation. The expression of VDUP1 was upregulated by overexpression of an oncogene, Ras. Enforced expression of VDUP1 increases ROS production and proliferation of Ras-overexpressing endothelial cells. Overexpression of VDUP1 increases the resistance to the anchorage-dependent cell death and tube formation of the Ras-overexpressing endothelial cell. In addition, the removal of ROS by ROS scavenger attenuates the effect of VDUP1 on tube formation. These results suggest that VDUP1 is involved in Ras-mediated angiogenesis via ROS generation in endothelial cells.

Osteoradionecrosis of the cervical spine complicated by pneumocephalus and meningitis in a nasopharyngeal cancer patient radically treated with radiotherapy 11 years ago

Superimposed infection of osteoradionecrotic cervical spine with cranial extension is difficult to treat and potentially fatal. This report describes the case of a middle-aged Chinese man 11 years post radical radiotherapy for nasopharyngeal cancer with no evidence of disease presenting initially with neck pain secondary to cervical osteoradionecrosis. He was re-admitted a month later with aspiration pneumonia associated with Streptococcus milleri bacteraemia, complicated by septic shock. The last re-admission was 2 months later with fever, expressive dysphasia and right upper motor neuron signs. There was interval increase of dental and peridental soft tissue mass, interval widening of atlantodental distance on MRI cervical spine associated with pneumocephalus, meningeal enhancement and pre-pontine soft tissue mass on CT brain consistent with infected osteoradionecrotic cervical spine complicated by cranial extension. The patient also had concomitant bilateral pneumonia and subsequently passed away from fulminant sepsis.

Carrier-mediated antiferromagnetic interlayer exchange coupling in diluted magnetic semiconductor multilayers Ga1-xMnxAs/GaAs:Be

We report the antiferromagnetic (AFM) interlayer exchange coupling between Ga0.97Mn0.03As ferromagnetic semiconductor layers separated by Be-doped GaAs spacers. Polarized neutron reflectivity reveals a characteristic splitting at the wave vector corresponding to twice the multilayer period, indicating that the coupling between the ferromagnetic layers is AFM. When the applied field is increased to above the saturation field, this AFM coupling is suppressed. This behavior is not observed when the spacers are undoped, suggesting that the observed AFM coupling is mediated by doped charge carriers.