Cost-minimization analysis of oral versus intravenous antibiotic treatment for Klebsiella pneumoniae liver abscess.

A cost-minimization analysis was conducted for Klebsiella pneumoniae liver abscess (KLA) patients enrolled in a randomized controlled trial which found oral ciprofloxacin to be non-inferior to intravenous (IV) ceftriaxone in terms of clinical outcomes. Healthcare service utilization and cost data were obtained from medical records and estimated from self-reported patient surveys in a non-inferiority trial of oral ciprofloxacin versus IV ceftriaxone administered to 152 hospitalized adults with KLA in Singapore between November 2013 and October 2017. Total costs were evaluated by category and payer, and compared between oral and IV antibiotic groups over the trial period of 12 weeks. Among the subset of 139 patients for whom cost data were collected, average total cost over 12 weeks was $16,378 (95% CI, $14,620-$18,136) for the oral ciprofloxacin group and $20,569 (95% CI, $18,296-$22,842) for the IV ceftriaxone group, largely driven by lower average outpatient costs, as the average number of outpatient visits was halved for the oral ciprofloxacin group. There were no other statistically significant differences, either in inpatient costs or in other informal healthcare costs. Oral ciprofloxacin is less costly than IV ceftriaxone in the treatment of Klebsiella liver abscess, largely driven by reduced outpatient service costs.Trial registration: ClinicalTrials.gov Identifier NCT01723150 (7/11/2012).

Favipiravir in early symptomatic COVID-19, a randomised placebo-controlled trial.

Background: Well tolerated antivirals administered early in the course of COVID-19 infection when the viremia is highest could prevent progression to severe disease. Favipiravir inhibits SARS-CoV-2 viral replication in vitro with evidence of clinical benefit in open label trials. Placebo controlled studies of people with early symptomatic COVID-19 with regular assessments of SARS-CoV-2 viral load can determine if it has an antiviral effect and improves clinical outcomes. Methods: People with PCR-confirmed COVID-19 and 5 days or less of symptoms were randomised 1:1 to favipiravir 1800 mg on day 1, then 800 mg twice daily or matched placebo for 14 days. SARS-CoV-2 viral load was quantitated from second daily self-collected nose-throat swabs while receiving study drug. The primary endpoint was time to virological cure defined as 2 successive swabs negative for SARS-CoV-2 by PCR and secondary outcomes were progression of disease severity, symptom resolution and safety. Findings: Between 31 July 2020 and 19 September 2021, 200 people were enrolled (199 in the community, 1 in hospital) with 190 receiving one or more doses of drug (modified intention to treat [mITT] population). There was no difference in time to virological cure (Log-rank p=0.6 comparing Kaplan Meier curves), progression to hospitalisation (14 favipiravir, 9 placebo; p=0.38), time to symptom resolution (cough, fever, sore throat) and there were no deaths. 51 people related an adverse event that was possibly drug related, but these were evenly distributed (n=24 favipiravir, n=27 placebo). Sensitivity analyses where the definition of virological cure was changed to: a single negative PCR, exclude datapoints based on the presence or absence of human DNA in the swab, a SARS-CoV-2 viral load < 300 copies/mL being considered negative all demonstrated no difference between arms. Interpretation: Favipiravir does not improve the time to virological cure or clinical outcomes and shows no evidence of an antiviral effect when treating early symptomatic COVID-19 infection. Funding: The study was supported in part by grants from the Commonwealth Bank Australia, the Lord Mayor's Charitable Foundation, Melbourne Australia and the Orloff Family Charitable Trust, Melbourne, Australia. JHM is supported by the Medical Research Future Fund, AYP, JT are supported by the Australian National Health and Medical Research Council.

Prospective study of policies and use of therapies for COVID-19 among Australian health services during 2020.

BACKGROUND: The COVID-19 pandemic has generated significant debate about how emerging infections can be treated in the absence of evidence-based therapies to combat disease. In particular, the use of off-label therapies outside of a clinical trial setting has been controversial. AIM: To longitudinally study policies and prescribing practices pertaining to therapies for COVID-19 in Australian health services during 2020. METHODS: Prospective data were collected from participating Australian health services who may care for patients with COVID-19 via an electronic portal. A single informant from each health service was emailed a survey link at regular intervals. Information was sought regarding changes to COVID-19 policy at their service and use of therapies for COVID-19. RESULTS: Overall, 78 hospitals were represented from 39 respondents with longitudinal data collection from May to December 2020. All Australian states/territories were represented with the majority (34/39; 87%) of respondents located in a major city. Just over half (20/39) of respondents had a written policy for COVID-19 therapy use at their health service at survey enrolment and policies changed frequently throughout the pandemic. Therapy use outside of a clinical trial was reported in 54% of health services, most frequently in Victoria, correlating with higher numbers of COVID-19 cases. At study commencement, hydroxychloroquine was most frequently used, with corticosteroids and remdesivir use increasingly throughout the study period. CONCLUSION: Our results reflect the reactive nature of prescribing of therapies for COVID-19 and highlight the importance of evidence-based guidelines to assist prescribers.

Stool metagenome analysis of patients with Klebsiella pneumoniae liver abscess and their domestic partners.

OBJECTIVES: Hypermucoviscous Klebsiella pneumoniae is an emerging cause of community-acquired liver abscess. The aim of this study was to investigate whether hypermucoviscous strains could be shared among households. METHODS: The clinical K. pneumoniae isolates from a cohort of 24 patients with Klebsiella liver abscess were genotyped, and the stool metagenomes of the index patients and their cohabiting domestic partners were analyzed. RESULTS: K. pneumoniae was identified in 33% of index patient stools, and one index patient's clinical isolate was identified in their domestic partner's stool. CONCLUSIONS: This could represent a transmission event or could represent exposure to a common environmental source.

Remdesivir in Coronavirus Disease 2019 (COVID-19) treatment: a review of evidence.

COVID-19 is an infectious disease caused by a novel ß-coronavirus, belonging to the same subgenus as the Severe Acute Respiratory Syndrome (SARS) virus. Remdesivir, an investigational broad-spectrum antiviral agent has previously demonstrated in vitro activity against Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and in vivo efficacy against other related coronaviruses in animal models. Its safety profile has been tested in a compassionate use setting for patients with COVID-19. The current therapeutic studies demonstrate clinical effectiveness of remdesivir in COVID-19 patients by shortening time to clinical recovery, and hospital stay. In this review, we critically analyze the current evidence of remdesivir against COVID-19 and dissect the aspects over its safety and efficacy. Based on existing data, remdesivir can be regarded as a potential therapeutic agent against COVID-19. Further large-scale, randomized placebo-controlled clinical trials are, however, awaited to validate these findings.

Endogenous endophthalmitis in Klebsiella pneumoniae pyogenic liver abscess: Systematic review and meta-analysis.

BACKGROUND: Endogenous endophthalmitis (EE) is a devastating complication that develops as a metastatic infection in patients with Klebsiella pneumoniae pyogenic liver abscess (KPPLA). The existing data are heterogeneous and the actual disease burden and risk factors for the development of EE among patients with KPPLA have not been systematically examined. We performed a systematic review and meta-analysis to examine the incidence of EE, temporal trend of EE, and risk factors for EE in patients with KPPLA. METHODOLOGY: The MEDLINE, EMBASE, Web of Science, and Cochrane Library databases were searched for articles published from inception to 2020 that evaluated the incidence of EE among patients with KPPLA. By a random-effects method, a pooled estimate of its incidence with 95% confidence intervals was estimated along with examination of its temporal and geographic variations. Pooled odds ratios were calculated for risk factors. RESULTS: Fifteen retrospective studies reporting data on 11889 patients with KPPLA met the inclusion criteria and were analyzed. With 217 patients developing EE, the pooled incidence of EE was 4.5% (95% confidence interval 2.4% to 8.2%). The heterogeneity was considerable and significant (Cochran's Q 243.5, p < 0.001, I2 = 94.2%). CONCLUSION: This meta-analysis estimates the actual incidence of EE among patients with KPPLA, where EE is reported in about 1 of 22 patients with KPPLA. Infection caused by K1 capsular serotype was an independent risk factor.

An adaptive randomised placebo controlled phase II trial of antivirals for COVID-19 infection (VIRCO): A structured summary of a study protocol for a randomised controlled trial.

OBJECTIVES: Primary objective: To determine the efficacy of a candidate antiviral on time to virological cure compared to standard of care within 14 days of randomisation Secondary objectives: • To determine the safety of the antiviral • To determine the clinical benefit of the antiviral over placebo according to the WHO 7-point ordinal scale • To determine the clinical benefit of the antiviral over placebo on time to resolution of clinical symptoms • To determine the effect of the antiviral over placebo on biomarkers of inflammation and immune activation TRIAL DESIGN: This is a multi-centre, triple-blind, randomised placebo controlled phase II, 2-arm trial with parallel-group design with allocation ratio 1:1. PARTICIPANTS: Inclusion Criteria: • Provision of informed consent by the participant • Age ≥18 years • Confirmed SARS-CoV-2 by nucleic acid testing in the past 5 days • COVID-19 related symptom initiation within 5 days • Female patients of childbearing potential must have a negative pregnancy test at Screening. Female patients of childbearing potential and fertile male patients who are sexually active with a female of childbearing potential must use highly effective methods of contraception throughout the study and for 1 week following the last dose of study treatment. EXCLUSION CRITERIA: • Known allergy to the study medication • Is on another clinical trial investigating an antiviral treatment for COVID-19 • Pregnancy • Patients with severe hepatic dysfunction equivalent to Grade C in the Child-Pugh classification • Patients with renal impairment requiring dialysis • Is deemed by the Investigator to be ineligible for any reason Participants will be recruited from, and the study visits will take place at Alfred Hospital, Monash Health, Austin Health in Victoria, Australia for hospitalised participants as well as recruitment in the community in participants homes for eligible people not requiring hospitalisation. INTERVENTION AND COMPARATOR: The first candidate antiviral is favipiravir Arm 1: Favipiravir 1800 mg favipiravir BD on Day 1 followed by 800 mg BD favipiravir for the next 13 days. Arm 2: Placebo MAIN OUTCOMES: Primary outcome: Time to virological cure as defined by 2 successive throat (or combined nose/throat) swabs negative for SARS-CoV-2 by nucleic acid testing during the 14 days after enrolment. RANDOMISATION: Randomisation performed at the Alfred Hospital Clinical Trials Pharmacy using computer generated block-randomisation lists with 6 participants per block. Within each block half of the participants will be randomised to the candidate antiviral and the other half to placebo. Randomisation is stratified by study site, with participants enrolled in the community considered as a study site. BLINDING (MASKING): Study participants, study investigators and the study statistician will be blinded to treatment allocation. NUMBERS TO BE RANDOMISED (SAMPLE SIZE): The study aims to recruit 190 people (95/arm) with the first candidate antiviral favipiravir TRIAL STATUS: Protocol version 2.0 Dated 31-Jul-2020. Recruitment will take place between July 2020 and December 2020. TRIAL REGISTRATION: clinicaltrials.gov NCT04445467 First posted 24-Jun-2020 FULL PROTOCOL: The full protocol is attached as an additional file, accessible from the Trials website (Additional file 1). In the interest in expediting dissemination of this material, the familiar formatting has been eliminated; this Letter serves as a summary of the key elements of the full protocol.

A blood RNA transcript signature for TB exposure in household contacts.

BACKGROUND: Current tools for diagnosing latent TB infection (LTBI) detect immunological memory of past exposure but are unable to determine whether exposure is recent. We sought to identify a whole-blood transcriptome signature of recent TB exposure. METHODS: We studied household contacts of TB patients; healthy volunteers without recent history of TB exposure; and patients with active TB. We performed whole-blood RNA sequencing (in all), an interferon gamma release assay (IGRA; in contacts and healthy controls) and PET/MRI lung scans (in contacts only). We evaluated differentially-expressed genes in household contacts (log2 fold change ≥1 versus healthy controls; false-discovery rate < 0.05); compared these to differentially-expressed genes seen in the active TB group; and assessed the association of a composite gene expression score to independent exposure/treatment/immunological variables. RESULTS: There were 186 differentially-expressed genes in household contacts (n = 26, age 22-66, 46% male) compared with healthy controls (n = 5, age 29-38, 100% male). Of these genes, 141 (76%) were also differentially expressed in active TB (n = 14, age 27-69, 71% male). The exposure signature included genes from inflammatory response, type I interferon signalling and neutrophil-mediated immunity pathways; and genes such as BATF2 and SCARF1 known to be associated with incipient TB. The composite gene-expression score was higher in IGRA-positive contacts (P = 0.04) but not related to time from exposure, isoniazid prophylaxis, or abnormalities on PET/MRI (all P > 0.19). CONCLUSIONS: Transcriptomics can detect TB exposure and, with further development, may be an approach of value for epidemiological research and targeting public health interventions.

Oral vs Intravenous Antibiotics for Patients With Klebsiella pneumoniae Liver Abscess: A Randomized, Controlled Noninferiority Study.

BACKGROUND: Klebsiella pneumoniae liver abscess (KLA) is emerging worldwide due to hypermucoviscous strains with a propensity for metastatic infection. Treatment includes drainage and prolonged intravenous antibiotics. We aimed to determine whether oral antibiotics were noninferior to continued intravenous antibiotics for KLA. METHODS: This noninferiority, parallel group, randomized, clinical trial recruited hospitalized adults with liver abscess and K. pneumoniae isolated from blood or abscess fluid who had received ≤7 days of effective antibiotics at 3 sites in Singapore. Patients were randomized 1:1 to oral (ciprofloxacin) or intravenous (ceftriaxone) antibiotics for 28 days. If day 28 clinical response criteria were not met, further oral antibiotics were prescribed until clinical response was met. The primary endpoint was clinical cure assessed at week 12 and included a composite of absence of fever in the preceding week, C-reactive protein <20 mg/L, and reduction in abscess size. A noninferiority margin of 12% was used. RESULTS: Between November 2013 and October 2017, 152 patients (mean age, 58.7 years; 25.7% women) were recruited, following a median 5 days of effective intravenous antibiotics. A total of 106 (69.7%) underwent abscess drainage; 71/74 (95.9%) randomized to oral antibiotics met the primary endpoint compared with 72/78 (92.3%) randomized to intravenous antibiotics (risk difference, 3.6%; 2-sided 95% confidence interval, -4.9% to 12.8%). Effects were consistent in the per-protocol population. Nonfatal serious adverse events occurred in 12/72 (16.7%) in the oral group and 13/77 (16.9%) in the intravenous group. CONCLUSIONS: Oral antibiotics were noninferior to intravenous antibiotics for the early treatment of KLA. CLINICAL TRIALS REGISTRATION: NCT01723150.

Sub-clinical abnormalities detected by PET/MRI in household tuberculosis contacts.

BACKGROUND: The understanding of early events following TB exposure is limited by traditional tests that rely on detection of an immune response to infection, which is delayed, or on imaging tests with low sensitivity for early disease. We investigated for evidence of lung abnormalities in heavily exposed TB contacts using PET/MRI. METHODS: 30 household contacts of 20 index patients underwent clinical assessment, IGRA testing, chest x-ray and PET/MRI scan using 18-F-FDG. MRI images were examined by a radiology/nuclear medicine dual-qualified physician using a standardised report form, while PET/MRI images were examined independently by another radiology/nuclear medicine dual-qualified physician using a similar form. Standardised uptake value (SUV) was quantified for each abnormal lesion. RESULTS: IGRA was positive in 40%. PET/MRI scan was abnormal in 30%, predominantly FDG uptake in hilar or mediastinal lymph nodes and lung apices. We did not identify any relationship between PET/MRI findings and degree of exposure or IGRA status. CONCLUSION: PET-based imaging may provide important insights into the natural history following exposure to TB that may not be available from traditional tests of TB immune response or imaging. The clinical significance of the abnormalities is uncertain and merits further investigation in longitudinal studies.

Population genomics of hypervirulent Klebsiella pneumoniae clonal-group 23 reveals early emergence and rapid global dissemination.

Severe liver abscess infections caused by hypervirulent clonal-group CG23 Klebsiella pneumoniae have been increasingly reported since the mid-1980s. Strains typically possess several virulence factors including an integrative, conjugative element ICEKp encoding the siderophore yersiniabactin and genotoxin colibactin. Here we investigate CG23's evolutionary history, showing several deep-branching sublineages associated with distinct ICEKp acquisitions. Over 80% of liver abscess isolates belong to sublineage CG23-I, which emerged in ~1928 following acquisition of ICEKp10 (encoding yersiniabactin and colibactin), and then disseminated globally within the human population. CG23-I's distinguishing feature is the colibactin synthesis locus, which reportedly promotes gut colonisation and metastatic infection in murine models. These data show circulation of CG23 K. pneumoniae decades before the liver abscess epidemic was first recognised, and provide a framework for future epidemiological and experimental studies of hypervirulent K. pneumoniae. To support such studies we present an open access, completely sequenced CG23-I human liver abscess isolate, SGH10.

Dengue virus not detected in human semen.

Zika and Ebola viruses can persist in semen and pose a risk for sexual transmission. To determine if dengue virus, another flavivirus, is similarly detectable in semen, we performed dengue PCR on semen in five patients with acute dengue virus infection. All five tested negative, suggesting that dengue does not pose a risk for sexual transmission.

Comparison of Diabetic and Non-diabetic Human Leukocytic Responses to Different Capsule Types of Klebsiella pneumoniae Responsible for Causing Pyogenic Liver Abscess.

The major risk factor for Klebsiella liver abscess (KLA) is type 2 diabetes mellitus (DM), but the immunological mechanisms involved in the increased susceptibility are poorly defined. We investigated the responses of neutrophils and peripheral blood mononuclear cells (PBMCs) to hypervirulent Klebsiella pneumoniae (hvKP), the causative agent of KLA. DNA and myeloperoxidase levels were elevated in the plasma of KLA patients compared to uninfected individuals indicating neutrophil activation, but diabetic status had no effect on these neutrophil extracellular trap (NET) biomarkers in both subject groups. Clinical hvKP isolates universally stimulated KLA patient neutrophils to produce NETs ex vivo, regardless of host diabetic status. Ability of representative capsule types (K1, K2, and non-K1/K2 strains) to survive intra- and extra-cellular killing by type 2 DM and healthy neutrophils was subsequently examined. Key findings were: (1) type 2 DM and healthy neutrophils exhibited comparable total, phagocytic, and NETs killing against hvKP, (2) phagocytic and NETs killing were equally effective against hvKP, and (3) hypermucoviscous K1 and K2 strains were more resistant to total, phagocytic, and NETs killing compared to the non-mucoviscous, non-K1/K2 strain. The cytokine response and intracellular killing ability of type 2 DM as well as healthy PBMCs upon encounter with the different capsule types was also examined. Notably, the IL-12-IFNγ axis and its downstream chemokines MIG, IP-10, and RANTES were produced at slightly lower levels by type 2 DM PBMCs than healthy PBMCs in response to representative K1 and non-K1/K2 strains. Furthermore, type 2 DM PBMCs have a mild defect in its ability to control hvKP replication relative to healthy PBMCs. In summary, our work demonstrates that type 2 DM does not overtly impact neutrophil intra- and extra-cellular killing of hvKP, but may influence cytokine/chemokine production and intracellular killing by PBMCs.

International tuberculosis research collaborations within Asia.

BACKGROUND: Asia bears more than half the global tuberculosis (TB) burden. Economic development in the region has increased available funding for biomedical research and opportunity for collaboration. We explored the extent of international tuberculosis research collaborations between institutions within Asia. METHODS: We conducted a Pubmed search for all articles with tuberculosis in the title published during a 12 month period with at least one author affiliation listed in Asia, then identified international collaborations from institution websites and internet searches. RESULTS: We identified 99 international collaborations involving an institution within Asia, of which only 8 (8.1%) were collaborations between Asian institutions. The remainder were with institutions outside of Asia. CONCLUSIONS: The paucity of intra-Asian international research collaboration represents a lost opportunity to optimise regional research funding, capacity building and the development of an Asia-relevant TB research agenda.

A comparison of 18F-FDG PET/MR with PET/CT in pulmonary tuberculosis.

PURPOSE: PET/computed tomography (CT) has been shown to detect lesions in patients with pulmonary tuberculosis (PTB) and may be useful for assessing PTB disease in clinical research studies. However, radiation dose is of concern for clinical research in individuals with an underlying curable disease. This study aimed to determine whether PET/MR is equivalent to PET/CT in PTB. MATERIALS AND METHODS: Ten patients with microbiologically confirmed PTB were recruited. Patients received 129.0±4.1 MBq of fluorine-18-fluorodeoxyglucose. Five of the 10 patients underwent a PET/MR scan, followed by PET/CT. The remaining five were first imaged on the PET/CT, followed by the PET/MRI. PET acquisition began at 66.7±14.4 min (mean±SD) after injection when performing PET/MR first (PET/CT: 117.2±5.6 min) and 92.4±7.6 min when patients were imaged on PET/MR second (PET/CT: 61.1±3.9 min). PET data were reconstructed iteratively with Ordinary-Poisson Ordered-Subset Expectation-Maximization and reconstruction parameters were matched across the two scanners. A visual lesion detection task and a standardized uptake value (SUV) analysis were carried out. The CT Hounsfield unit values of PTB lesions were also compared with MR-based attenuation correction mu-map tissue classes. RESULTS: A total of 108 PTB lesions were detected on PET/MR and 112 on PET/CT. SUV analysis was carried out on 50 of these lesions that were observed with both modalities. Mean standardized uptake value (SUVmean) and maximum standardized uptake value (SUVmax) were significantly lower on PET/MR (SUVmean: 2.6±1.4; SUVmax: 4.3±2.5) than PET/CT (SUVmean: 3.5±1.5; SUVmax: 5.3±2.4). CONCLUSION: PET/MR visual performance was shown to be comparable to PET/CT in terms of the number of PTB lesions detected. SUVs were significantly lower on PET/MR. Dixon-based attenuation correction underestimates the linear attenuation coefficient of PTB lesions, resulting in lower SUVs compared with PET/CT. However, the use of PET/MR to measure the response of lung lesions to assess response to treatment in research studies is unlikely to be affected by these differences in quantification.

Prospective single-arm interventional pilot study to assess a smartphone-based system for measuring and supporting adherence to medication.

OBJECTIVES: Suboptimal medication adherence for infectious diseases such as tuberculosis (TB) results in poor clinical outcomes and ongoing infectivity. Directly observed therapy (DOT) is now standard of care for TB treatment monitoring but has a number of limitations. We aimed to develop and evaluate a smartphone-based system to facilitate remotely observed therapy via transmission of videos rather than in-person observation. DESIGN: We developed an integrated smartphone and web-based system (Mobile Interactive Supervised Therapy, MIST) to provide regular medication reminders and facilitate video recording of pill ingestion at predetermined timings each day, for upload and later review by a healthcare worker. We evaluated the system in a single arm, prospective study of adherence to a dietary supplement. Healthy volunteers were recruited through an online portal. Entry criteria included age ≥21 and owning an iOS or Android-based device. Participants took a dietary supplement pill once, twice or three-times a day for 2 months. We instructed them to video each pill taking episode using the system. OUTCOME: Adherence as measured by the smartphone system and by pill count. RESULTS: 42 eligible participants were recruited (median age 24; 86% students). Videos were classified as received-confirmed pill intake (3475, 82.7% of the 4200 videos expected), received-uncertain pill intake (16, <1%), received-fake pill intake (31, <1%), not received-technical issues (223, 5.3%) or not received-assumed non-adherence (455, 10.8%). Overall median estimated participant adherence by MIST was 90.0%, similar to that obtained by pill count (93.8%). There was a good relationship between participant adherence as measured by MIST and by pill count (Spearmans rs 0.66, p<0.001). CONCLUSIONS: We have demonstrated the feasibility, acceptability and accuracy of a smartphone-based adherence support and monitoring system. The system has the potential to supplement and support the provision of DOT for TB and also to improve adherence in other conditions such as HIV and hepatitis C.

Differential host susceptibility and bacterial virulence factors driving Klebsiella liver abscess in an ethnically diverse population.

Hypervirulent Klebsiella pneumoniae is an emerging cause of community-acquired pyogenic liver abscess. First described in Asia, it is now increasingly recognized in Western countries, commonly afflicting those with Asian descent. This raises the question of genetic predisposition versus geospecific strain acquisition. We leveraged on the Antibiotics for Klebsiella Liver Abscess Syndrome Study (A-KLASS) clinical trial ongoing in ethnically diverse Singapore, to prospectively examine the profiles of 70 patients together with their isolates' genotypic and phenotypic characteristics. The majority of isolates belonged to capsule type K1, a genetically homogenous group corresponding to sequence-type 23. The remaining K2, K5, K16, K28, K57 and K63 isolates as well as two novel cps isolates were genetically heterogeneous. K1 isolates carried higher frequencies of virulence-associated genes including rmpA (regulator of mucoid phenotype A), kfu (Klebsiella ferric uptake transporter), iuc (aerobactin), iro (salmochelin) and irp (yersiniabactin) than non-K1 isolates. The Chinese in our patient cohort, mostly non-diabetic, had higher prevalence of K1 infection than the predominantly diabetic non-Chinese (Malays, Indian and Caucasian). This differential susceptibility to different capsule types among the various ethnic groups suggests patterns of transmission (e.g. environmental source, familial transmission) and/or genetic predisposition unique to each race despite being in the same geographical location.

A Novel Approach to CT, MR, and PET Examination of Patients with Infections Requiring Stringent Airborne Precautions.

PURPOSE: To investigate the feasibility of using a modified portable isolation chamber, which conforms to Centers for Disease Control and Prevention (CDC) isolation requirements, in the imaging of infectious patients. MATERIALS AND METHODS: This study was approved by the ethics committee, and all participants gave written informed consent. In this prospective study, the isolation chamber was assessed for computed tomographic (CT), magnetic resonance (MR), and positron emission tomographic (PET) image uniformity and noise by using uniform phantoms. For each modality, equivalent phantom examinations were performed without the isolation chamber. Paired analyses of the differences from these baseline values were conducted by finding the mean difference in the matched sections for each image quality parameter. A potential increase in CT patient dose was assessed, and MR radiofrequency (RF) interference was monitored. Eight participants with active pulmonary tuberculosis (mean age, 48.1 years; age range, 26-88 years; five men, three women) were then examined within a hybrid PET/MR imager. The 95% confidence intervals for the difference in the two matched population means were determined by using the two-sided t distribution for each of the phantom study imaging modalities. RESULTS: Phantom images were evaluated for image uniformity and noise. Increased image noise can affect low contrast resolution, which has the potential to mimic or mask abnormalities when the differences between healthy and diseased tissues are small; clinically, CT image noise is maintained at a constant level with dose modulation. Increased attenuation of annihilation photons, when not corrected for, could lead to photopenic areas on the PET image; PET image nonuniformity complied with guidelines. Artifacts on the MR image due to RF noise spikes could mask abnormalities; paired analysis of variations in MR imaging mean signal-to-noise ratio and uniformity from baseline were within 5% for both gradient-echo and spin-echo sequences. In the eight participants who underwent imaging, the increased radiation dose for the attenuation of the isolation chamber would have resulted in a mean increase in patient size-specific dose estimate of 0.32 mGy ± 0.04 (standard deviation). The RF noise assessment revealed no prominent increase at any frequency band. The eight participants were examined within the isolation chamber without incident. CONCLUSION A modified portable isolation chamber, which conforms to CDC infection control guidelines, was found to be feasible within the confines of CT, MR imaging, and PET environments.

Impact of Regional Vein Thrombosis in Patients with Klebsiella pneumoniae Liver Abscess.

Klebsiella liver abscess (KLA) is an emerging infection in Asia caused by hypermucoviscous strains of Klebsiella pneumoniae. It is associated with thrombophlebitis of portal and hepatic veins. The natural history and role of anticoagulation for this regional thrombophlebitis is unclear. In a retrospective study of 169 subjects with KLA over 7 years, thrombophlebitis was identified in 53/169 (31.4%). Only 1 received therapeutic anticoagulation. Despite this 30/49 (73.2%) of those with follow up scan available showed improvement or recanalization (mean duration between scans 44 days). Abscess resolution was associated with improvement in thrombophlebitis.