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INTRODUCTION: No previous systematic reviews have comprehensively investigated the features of Xpert MTB/XDR and other rapid tests to diagnose pre-XDR/XDR-TB. The aim of this systematic review is to assess existing rapid diagnostics for pre-XDR/XDR-TB from a point-of-care perspective and describe their technical characteristics (i.e., sensitivity, specificity, positive and negative predictive values). METHODS: Embase, PubMed, Scopus, and Web of Science were searched to detect the articles focused on the accuracy of commercially available rapid molecular diagnostic tests for XDR-TB according to PRISMA guidelines. The analysis compared the diagnostic techniques and approaches in terms of sensitivity, specificity, laboratory complexity, time to confirmed diagnosis. RESULTS: Of 1298 records identified, after valuating article titles and abstracts, 97 (7.5%) records underwent full-text evaluation and 38 records met the inclusion criteria. Two rapid World Health Organization (WHO)-endorsed tests are available: Xpert MTB/XDR and GenoType MTBDRsl (VER1.0 and VER 2.0). Both tests had similar performance, slightly favouring Xpert, although only 2 studies were available (sensitivity 91.4-94; specificity 98.5-99; accuracy 97.2-97.7; PPV 88.9-99.1; NPV 95.8-98.9). CONCLUSIONS: Xpert MTB/XDR could be suggested at near-point-of-care settings to be used primarily as a follow-on test for laboratory-confirmed TB, complementing existing rapid tests detecting at least rifampicin-resistance. Both Xpert MTB/XDR and GenoType MTBDRsl are presently diagnosing what WHO defined, in 2021, as pre-XDR-TB.

BACKGROUND: Increasing evidence suggests that post-TB lung disease (PTLD) causes significant morbidity and mortality. The aim of these clinical standards is to provide guidance on the assessment and management of PTLD and the implementation of pulmonary rehabilitation (PR).METHODS: A panel of global experts in the field of TB care and PR was identified; 62 participated in a Delphi process. A 5-point Likert scale was used to score the initial ideas for standards and after several rounds of revision the document was approved (with 100% agreement).RESULTS: Five clinical standards were defined: Standard 1, to assess patients at the end of TB treatment for PTLD (with adaptation for children and specific settings/situations); Standard 2, to identify patients with PTLD for PR; Standard 3, tailoring the PR programme to patient needs and the local setting; Standard 4, to evaluate the effectiveness of PR; and Standard 5, to conduct education and counselling. Standard 6 addresses public health aspects of PTLD and outcomes due to PR.CONCLUSION: This is the first consensus-based set of Clinical Standards for PTLD. Our aim is to improve patient care and quality of life by guiding clinicians, programme managers and public health officers in planning and implementing adequate measures to assess and manage PTLD.

Coronavirus disease has disrupted tuberculosis services globally. Data from 33 centers in 16 countries on 5 continents showed that attendance at tuberculosis centers was lower during the first 4 months of the pandemic in 2020 than for the same period in 2019. Resources are needed to ensure tuberculosis care continuity during the pandemic.

BackgroundUnderstanding the pathophysiology of central nervous system tuberculosis (CNS-TB) is hampered by the lack of a good pre-clinical model that mirrors the human CNS-TB infection. We developed a murine CNS-TB model that demonstrates neurobehavioral changes with similar immunopathology with human CNS-TB.MethodsWe injected twoMycobacterium tuberculosis(M.tb) strains, H37Rv and CDC1551, respectively, into two mouse strains, C3HeB/FeJ andNos2-/-mice, either into the third ventricle or intravenous. We compared the neurological symptoms, histopathological changes and levels of adhesion molecules, chemokines, and inflammatory cytokines in the brain induced by the infections through different routes in different strains.ResultsIntra-cerebroventricular infection ofNos2-/-mice withM.tbled to development of neurological signs and more severe brain granulomas compared to C3HeB/FeJ mice. Compared with CDC1551M.tb, H37RvM.tbinfection resulted in a higher neurobehavioral score and earlier mortality. Intra-cerebroventricular infection caused necrotic neutrophil-dominated pyogranulomas in the brain relative to intravenous infection which resulted in disseminated granulomas and mycobacteraemia. Histologically, intra-cerebroventricular infection ofNos2-/-mice withM.tbresembled human CNS-TB brain biopsy specimens. H37Rv intra-cerebroventricular infected mice demonstrated higher brain concentrations of inflammatory cytokines, chemokines and adhesion molecule ICAM-1 than H37Rv intravenous-infected mice.ConclusionsIntra-cerebroventricular infection ofNos2-/-mice with H37Rv creates a murine CNS-TB model that resembled human CNS-TB immunopathology, exhibiting the worst neurobehavioral score with a high and early mortality reflecting disease severity and its associated neurological morbidity. Our murine CNS-TB model serves as a pre-clinical platform to dissect host-pathogen interactions and evaluate therapeutic agents for CNS-TB.

BACKGROUND: Matrix metalloproteinases (MMPs) are key regulators of tissue destruction in tuberculosis (TB) and may be targets for host-directed therapy. We conducted a phase II double-blind, randomized, controlled trial investigating doxycycline, a licensed broad-spectrum MMP inhibitor, in patients with pulmonary TB. METHODS: Thirty patients with pulmonary TB were enrolled within 7 days of initiating anti-TB treatment and randomly assigned to receive either 100 mg doxycycline or placebo twice a day for 14 days, in addition to standard care. RESULTS: Whole blood RNA-sequencing demonstrated that doxycycline accelerated restoration of dysregulated gene expression in TB towards normality, rapidly down-regulating type I and II interferon and innate immune response genes, and up-regulating B-cell modules relative to placebo. The effects persisted for 6 weeks after doxycycline discontinuation, concurrent with suppressed plasma MMP-1. Doxycycline significantly reduced sputum MMP-1, -8, -9, -12 and -13, suppressed type I collagen and elastin destruction, reduced pulmonary cavity volume without altering sputum mycobacterial loads, and was safe. CONCLUSION: Adjunctive doxycycline with standard anti-TB treatment suppressed pathological MMPs in PTB patients. Larger studies on adjunctive doxycycline to limit TB immunopathology are merited. TRIAL REGISTRATION: ClinicalTrials.gov NCT02774993. FUNDING: Singapore National Medical Research Council (NMRC/CNIG/1120/2014, NMRC/Seedfunding/0010/2014, NMRC/CISSP/2015/009a); the Singapore Infectious Diseases Initiative (SIDI/2013/013); National University Health System (PFFR-28 January 14, NUHSRO/2014/039/BSL3-SeedFunding/Jul/01); the Singapore Immunology Network Immunomonitoring platform (BMRC/IAF/311006, H16/99/b0/011, NRF2017_SISFP09); an ExxonMobil Research Fellowship, NUHS Clinician Scientist Program (NMRC/TA/0042/2015, CSAINV17nov014); the UK Medical Research Council (MR/P023754/1, MR/N006631/1); a NUS Postdoctoral Fellowship (NUHSRO/2017/073/PDF/03); The Royal Society Challenge Grant (CHG\R1\170084); the Sir Henry Dale Fellowship, Wellcome Trust (109377/Z/15/Z); and A*STAR.

Objectives: To examine the prevalence and characteristics of HIV-tuberculosis (TB) co-infected patients in Singapore, an intermediate TB-burden country. Methods: Retrospective data across 11 years was obtained from the National University Hospital (NUH), a quaternary hospital and the National Centre for Infectious Diseases (NCID), the national HIV center. Results: From December 2005 to December 2016, 4015 HIV-infected patients were managed at NUH and NCID, of whom, respectively, 48 and 272 were diagnosed with active TB disease. Only 2 patients (0.6%) were screened for latent TB infection on HIV diagnosis. Mean CD4 count at TB diagnosis was 125.0 +/- 153.9 cells/mm(3). More patients with HIV diagnosed >= 6 weeks before TB (41%) were associated with CD4 counts > 200 cells/mm(3) than patients with TB diagnosed > 6 weeks before HIV (2%). Of 124 (38.6%) HIV-TB patients with CD4 count

Accessible and adaptable nucleic acid diagnostics remains a critical challenge in managing the evolving COVID‐19 pandemic. Here, an integrated molecular nanotechnology that enables direct and programmable detection of SARS‐CoV‐2 RNA targets in native patient specimens is reported. Termed synergistic coupling of responsive equilibrium in enzymatic network (SCREEN), the technology leverages tunable, catalytic molecular nanostructures to establish an interconnected, collaborative architecture. SCREEN mimics the extraordinary organization and functionality of cellular signaling cascades. Through programmable enzyme–DNA nanostructures, SCREEN activates upon interaction with different RNA targets to initiate multi‐enzyme catalysis; through system‐wide favorable equilibrium shifting, SCREEN directly transduces a single target binding into an amplified electrical signal. To establish collaborative equilibrium coupling in the architecture, a computational model that simulates all reactions to predict overall performance and optimize assay configuration is developed. The developed platform achieves direct and sensitive RNA detection (approaching single‐copy detection), fast response (assay reaction is completed within 30 min at room temperature), and robust programmability (across different genetic loci of SARS‐CoV‐2). When clinically evaluated, the technology demonstrates robust and direct detection in clinical swab lysates to accurately diagnose COVID‐19 patients., A molecular nanotechnology is developed utilizing interconnected enzyme–DNA nanostructures to achieve cooperative multi‐enzyme catalysis. Through programmable nanostructures and favorable equilibrium coupling in the system architecture, the technology achieves sensitive and versatile detection for the direct measurement of SARS‐CoV‐2 RNA targets in native patient specimens (30 min at room temperature).

Transition-state molecular switches enable hyper responsive detection of SARS-CoV-2 in native clinical samples., Despite the importance of nucleic acid testing in managing the COVID-19 pandemic, current detection approaches remain limited due to their high complexity and extensive processing. Here, we describe a molecular nanotechnology that enables direct and sensitive detection of viral RNA targets in native clinical samples. The technology, termed catalytic amplification by transition-state molecular switch (CATCH), leverages DNA-enzyme hybrid complexes to form a molecular switch. By ratiometric tuning of its constituents, the multicomponent molecular switch is prepared in a hyperresponsive state—the transition state—that can be readily activated upon the binding of sparse RNA targets to turn on substantial enzymatic activity. CATCH thus achieves superior performance (~8 RNA copies/μl), direct fluorescence detection that bypasses all steps of PCR (

ObjectivesTuberculosis (TB) is a common infection in HIV patients. Our study aims to determine the prevalence and characteristics of HIV-TB co-infected patients in Singapore, a high-income, intermediate TB-burden country.MethodsRetrospective data of 11-years was obtained from the National University Hospital (NUH), a quaternary care hospital and the National Centre for Infectious Diseases, the national HIV centre.ResultsFrom December 2005 to December 2016, 48 out of 819 HIV patients and 272 out of 3,196 HIV patients who were managed in NUH and TTSH respectively, were diagnosed with TB. 89.1% (n=285) were males and 2 (0.6%) were screened for latent TB on HIV diagnosis. The median age at TB diagnosis was 47.3 years old (Interquartile range, IQR 41-57). Mean CD4 count at TB diagnosis was 125.0 ± 153.9 cells/mm3. 124 (38.6%) patients had CD4 < 50 cells/mm3. 41.3% (n=132) of patients had HIV diagnosed at least 6 weeks before TB diagnosis, indicating an opportunity to initiate latent TB preventive therapy. 55.0% (n=176) had HIV and TB concomitantly diagnosed within 6 weeks whilst 2.25% (n=7) had TB diagnosed before HIV. Of those HIV-TB co-infected patients with CD4 ≤ 50 cells/mm3, 18 (14.2%) had anti-retroviral therapy (ART) started ConclusionThere is a lack of latent TB screening in HIV patients and a delay in initiation of ART in HIV-TB patients with low CD4 counts in our study. Clinical practices can be further improved for the benefit of outcomes in HIV-TB patients.

Contains fulltext : 225854.pdf (Publisher’s version ) (Open Access) Major epidemics, including some that qualify as pandemics, such as severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS), HIV, influenza A (H1N1)pdm/09 and most recently COVID-19, affect the lung. Tuberculosis (TB) remains the top infectious disease killer, but apart from syndemic TB/HIV little is known regarding the interaction of viral epidemics and pandemics with TB. The aim of this consensus-based document is to describe the effects of viral infections resulting in epidemics and pandemics that affect the lung (MERS, SARS, HIV, influenza A (H1N1)pdm/09 and COVID-19) and their interactions with TB. A search of the scientific literature was performed. A writing committee of international experts including the European Centre for Disease Prevention and Control Public Health Emergency (ECDC PHE) team, the World Association for Infectious Diseases and Immunological Disorders (WAidid), the Global Tuberculosis Network (GTN), and members of the European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Study Group for Mycobacterial Infections (ESGMYC) was established. Consensus was achieved after multiple rounds of revisions between the writing committee and a larger expert group. A Delphi process involving the core group of authors (excluding the ECDC PHE team) identified the areas requiring review/consensus, followed by a second round to refine the definitive consensus elements. The epidemiology and immunology of these viral infections and their interactions with TB are discussed with implications for diagnosis, treatment and prevention of airborne infections (infection control, viral containment and workplace safety). This consensus document represents a rapid and comprehensive summary on what is known on the topic.

Background On January 30, COVID-19 was declared a Public Health Emergency of International Concern—a week after Singapore’s first imported case and 5 days before local transmission. The National University Hospital (NUH) is Singapore’s third largest hospital with 1200 beds, heavy clinical workloads, and major roles in research and teaching. Main body With memories of SARS still vivid, there was an urgent requirement for the NUH Division of Infectious Diseases to adapt—undergoing major reorganization to face rapidly changing priorities while ensuring usual essential services and standards. Leveraging on individual strengths, our division mobilized to meet the demands of COVID-19 while engaging in high-level coordination, strategy, and advocacy. We present our experience of the 60 days since the nation’s first case. During this time, our hospital has managed 3030 suspect cases, including 1300 inpatients, 37 confirmed cases, and overseen 4384 samples tested for COVID-19. Conclusion Complex hospital adaptations were supported by an unprecedented number of workflows and coordination channels essential to safe and effective operations. The actions we describe, aligned with international recommendations and emerging evidence-based best practices, may serve as a framework for other divisions and institutions facing the spread of COVID-19 globally.

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) disease (COVID-19) pandemic has attracted interest because of its global rapid spread, clinical severity, high mortality rate, and capacity to overwhelm healthcare systems [1, 2]. SARS-CoV-2 transmission occurs mainly through droplets, although surface contamination contributes and debate continues on aerosol transmission [3–5].

Background Biomedical research is overseen by numerous Institutional Review Boards (IRBs) in Singapore but there has been no research that examines how the research review process is perceived by the local research community nor is there any systematic data on perceptions regarding the review process or other research ethics processes and IRB characteristics. The aim of this study was to ascertain general views regarding the overall perceived value of ethics review processes; to measure perceptions about local IRB functions and characteristics; to identify IRB functions and characteristics viewed as important; and to compare these views with those of other international studies. Methods An online survey was used with the main component being the IRB-Researcher Assessment Tool (IRB-RAT), a validated tool, to evaluate perceptions of ideal and actual IRB functions and characteristics held by Singaporean researchers and research support staff. Data were analysed descriptively first, with mean and SD of each item of IRB-RAT questionnaire reported, excluding the respondents whose answers were unknown or not applicable. The Wilcoxon Sign Rank test was used to compare the ideal and actual ratings of each IRB-RAT item, while the Mann-Whitney U test was used to compare the ratings of each IRB-RAT item between respondents with different characteristics. The Z-test was used to compare the mean ratings of our cohort with the mean ratings reported in the literature. The correlation between our mean ideal scores and those of two international studies also employing the IRB-RAT was examined. Results Seventy-one respondents completed the survey. This cohort generally held positive views of the impact of the ethics review process on: the quality of research; establishing and maintaining public trust in research; the protection of research participants; and on the scientific validity of research. The most important ideal IRB characteristics were timeliness, upholding participants’ rights while also facilitating research, working with investigators to find solutions when there are disagreements, and not allowing biases to affect reviews. For almost all 45 IRB-RAT statements, the rating of the importance of the characteristic was higher than the rating of how much that characteristic was descriptive of IRBs the respondents were familiar with. There was a significant strong correlation between our study’s scores on the ideal IRB characteristics and those of the first and largest published study that employed the IRB-RAT, the US National Validation (USNV) sample in Keith-Spiegel et al. [19]. Conclusions An understanding of the perceptions held by Singaporean researchers and research support staff on the value that the ethics review process adds, their perceptions of actual IRB functions and characteristics as well as what they view as central to high functioning IRBs is the first step to considering the aspects of the review process that might benefit from improvements. This study provides insight into how our cohort compares to others internationally and highlights strengths and areas for improvement of Singapore IRBs as perceived by a small sample of the local research community. Such insights provide a springboard for additional research and may assist in further enhancing good relations so that both are working towards the same end.

Accurate and accessible nucleic acid diagnostics is critical to reducing the spread of COVID-19 and resuming socioeconomic activities. Here, we present an integrated platform for the direct detection of SARS-CoV-2 RNA targets near patients. Termed electrochemical system integrating reconfigurable enzyme-DNA nanostructures (eSIREN), the technology leverages responsive molecular nanostructures and automated microfluidics to seamlessly transduce target-induced molecular activation into an enhanced electrochemical signal. Through responsive enzyme-DNA nanostructures, the technology establishes a molecular circuitry that directly recognizes specific RNA targets and catalytically enhances signaling; only upon target hybridization, the molecular nanostructures activate to liberate strong enzymatic activity and initiate cascading reactions. Through automated microfluidics, the system coordinates and interfaces the molecular circuitry with embedded electronics; its pressure actuation and liquid-guiding structures improve not only analytical performance but also automated implementation. The developed platform establishes a detection limit of 7 copies of RNA target per μl, operates against the complex biological background of native patient samples, and is completed in

Latent tuberculosis infection was the term traditionally used to indicate tuberculosis (TB) infection. This term was used to define “a state of persistent immune response to stimulation by Mycobacterium tuberculosis antigens through tests such as the tuberculin skin test (TST) or an interferon-γ release assay (IGRA) without clinically active TB”. Recent evidence indicates that the spectrum from TB infection to TB disease is much more complex, including a “continuum” of situations didactically reported as uninfected individual, TB infection, incipient TB, subclinical TB without signs/symptoms, subclinical TB with unrecognised signs/symptoms, and TB disease with signs/symptoms. Recent evidence suggests that subclinical TB is responsible for important M. tuberculosis transmission. This review describes the different stages described above and their relationships. It also summarises the new developments in prevention, diagnosis and treatment of TB infection as well as their public health and policy implications. Educational aims To describe the evolution of the definition of “tuberculosis infection” and didactically describe the continuum of stages existing between TB infection and disease. To discuss the recommended approaches to prevent, diagnose and treat TB infection., The evolution from TB infection to disease is now described as a “continuum process”. Understanding of this is important to appreciate what is new on prevention, diagnosis and treatment of TB infection. https://bit.ly/3jauRKA

Programmable Detection of SARS‐CoV‐2 In article number 2101155, Huilin Shao and co‐workers report the collaborative coupling of enzyme–DNA nanostructures to establish multi‐enzyme catalysis. Through programmable nanostructures and favorable equilibrium architecture, the technology achieves direct and sensitive detection of SARS‐CoV‐2 RNA in native patient samples, within 30 minutes at room temperature. [Image: see text]

Central nervous system tuberculosis (CNS TB) has a high mortality and morbidity associated with severe inflammation. The blood-brain barrier (BBB) protects the brain from inflammation but the mechanisms causing BBB damage in CNS TB are uncharacterized. We demonstrate that Mycobacterium tuberculosis (Mtb) causes breakdown of type IV collagen and decreases tight junction protein (TJP) expression in a co-culture model of the BBB. This increases permeability, surface expression of endothelial adhesion molecules and leukocyte transmigration. TJP breakdown was driven by Mtb-dependent secretion of matrix metalloproteinase (MMP)-9. TJP expression is regulated by Sonic hedgehog (Shh) through transcription factor Gli-1. In our model, the hedgehog pathway was downregulated by Mtb-stimulation, but Shh levels in astrocytes were unchanged. However, Scube2, a glycoprotein regulating astrocyte Shh release was decreased, inhibiting Shh delivery to brain endothelial cells. Activation of the hedgehog pathway by addition of a Smoothened agonist or by addition of exogenous Shh, or neutralizing MMP-9 activity, decreased permeability and increased TJP expression in the Mtb-stimulated BBB co-cultures. In summary, the BBB is disrupted by downregulation of the Shh pathway and breakdown of TJPs, secondary to increased MMP-9 activity which suggests that these pathways are potential novel targets for host directed therapy in CNS TB.

Pulmonary tuberculosis (TB) is caused by inhalation of Mycobacterium tuberculosis, which damages the bronchial epithelial barrier to establish local infection. Matrix metalloproteinase-1 plays a crucial role in the immunopathology of TB, causing breakdown of type I collagen and cavitation, but this collagenase is also potentially involved in bronchial epithelial repair. We hypothesized that the extracellular matrix (ECM) modulates M. tuberculosis-driven matrix metalloproteinase-1 expression by human bronchial epithelial cells (HBECs), regulating respiratory epithelial cell migration and repair. Medium from monocytes stimulated with M. tuberculosis induced collagenase activity in bronchial epithelial cells, which was reduced by ~87% when cells were cultured on a type I collagen matrix. Matrix metalloproteinase-1 had a focal localization, which is consistent with cell migration, and overall secretion decreased by 32% on type I collagen. There were no associated changes in the specific tissue inhibitors of metalloproteinases. Decreased matrix metalloproteinase-1 secretion was due to ligand-binding to the α2β1 integrin and was dependent on the actin cytoskeleton. In lung biopsies, samples from patients with pulmonary TB, integrin α2β1 is highly expressed on the bronchial epithelium. Areas of lung with disrupted collagen matrix showed an increase in matrix metalloproteinases-1 expression compared with areas where collagen was comparable to control lung. Type I collagen matrix increased respiratory epithelial cell migration in a wound-healing assay, and this too was matrix metalloproteinase-dependent, since it was blocked by the matrix metalloproteinase inhibitor GM6001. In summary, we report a novel mechanism by which α2β1-mediated signals from the ECM modulate matrix metalloproteinase-1 secretion by HBECs, regulating their migration and epithelial repair in TB.

The authors present the case of an isolated gonococcal paravertebral abscess with an epidural component in a 42-year-old man. A primary epidural abscess of the spine is a rare condition and is most commonly caused by Staphylococcus aureus. In this report, the authors present their therapeutic decisions and review the relevant literature on disseminated gonococcal infection in a patient presenting with an epidural abscess. A 42-year-old Indonesian man was admitted with symptoms of neck and upper back pain and bilateral lower-limb weakness. Clinical examination was unremarkable apart from tenderness over the lower cervical spine. Postgadolinium T1-weighted MRI of the cervical and thoracic spine demonstrated an enhancing lesion in the right paraspinal and epidural soft tissue at C-6 to T1–2, in keeping with a spinal epidural abscess. The patient underwent laminectomy of C-7 and T-1 with abscess drainage. Tissue cultures subsequently grew Neisseria gonorrhoeae that was resistant to quinolones by genotyping. Upon further questioning, the patient admitted to unprotected sexual intercourse with commercial sex workers. Further investigations showed that he was negative for other sexually transmitted infections. Postoperatively, he received a course of beta-lactam antibiotics with good recovery. Clinicians should be aware of this unusual disseminated gonococcal infection manifested in any patient with the relevant risk factors.

Background and objective: Patients with community-acquired Acinetobacter baumannii (AB) pneumonia have been reported from subtropical countries. We investigated the epidemiology, clinical and microbiological characteristics of community-acquired pneumonia (CAP) due to AB in Singapore. Method: A retrospective case series was performed over a 21-month period at two institutions. Results: From 1 January 2007 to 30 September 2008, eight patients were diagnosed with CAP due to AB. Seven had bacteraemia and five were sputum culture-positive. The median age at presentation was 58.5 years (range 45–76 years). Five patients (71.4%) acquired the pneumonia in the warmer months of June to September. Presentation was acute, with a median duration of 2.5 days (range 1–7 days). The median Acute Physiology and Chronic Health Evaluation II score was 28.5 (range 6–36). Six patients presented with septic shock, lactic acidosis, acute kidney injury and respiratory failure, necessitating ICU care; five of thesepatients eventually died. All patients received empirical antibiotics, including third-generation cephalosporins, which were inactive against the organism. All isolates were susceptible to ampicillin/sulbactam, ciprofloxacin, co-trimoxazole, aminoglycosides and imipenem. Conclusions: Community-acquired AB pneumonia have a fulminant course. In a region endemic for melioidosis and severe community-acquired Klebsiella pneumoniae, the challenge lies in rapid identification and initiation of appropriate empirical antibiotics to improve the survival of patients with AB CAP.

Influenza pandemics have been a major concern owing to the high rates of morbidity and mortality, as well as high attack rates worldwide. Pandemics in 1918, 1957 and 1968 were caused by the introduction of novel antigenic strains of influenza. With the recent re-emergence of the avian influenza H5N1 during the 2004-2006 epizootic, there are concerns for another pandemic, which would potentially claim the lives of millions. While vaccination is the only proven means of controlling or eliminating a viral infection, it is recognized that vaccine development will take time and, thus, there has been a renewed interest in the potential role of antivirals in the prevention and control of pandemic influenza.

Pulmonary cavities, the hallmark of tuberculosis (TB), are characterized by high mycobacterial load and perpetuate the spread of M. tuberculosis. The mechanism of matrix destruction resulting in cavitation is not well defined. Neutrophils are emerging as key mediators of TB immunopathology and their influx are associated with poor outcomes. We investigated neutrophil-dependent mechanisms involved in TB-associated matrix destruction using a cellular model, a cohort of 108 patients, and in separate patient lung biopsies. Neutrophil-derived NF-kB-dependent matrix metalloproteinase-8 (MMP-8) secretion was up-regulated in TB and caused matrix destruction both in vitro and in respiratory samples of TB patients. Collagen destruction induced by TB infection was abolished by doxycycline, a licensed MMP inhibitor. Neutrophil extracellular traps (NETs) contain MMP-8 and are increased in samples from TB patients. Neutrophils lined the circumference of human pulmonary TB cavities and sputum MMP-8 concentrations reflected TB radiological and clinical disease severity. AMPK, a central regulator of catabolism, drove neutrophil MMP-8 secretion and neutrophils from AMPK-deficient patients secrete lower MMP-8 concentrations. AMPK-expressing neutrophils are present in human TB lung biopsies with phospho-AMPK detected in nuclei. These data demonstrate that neutrophil-derived MMP-8 has a key role in the immunopathology of TB and is a potential target for host-directed therapy in this infectious disease., Author Summary Neutrophil infiltration is characteristic of immune-induced pathology in tuberculosis but mechanisms whereby neutrophils cause tissue destruction are not fully understood. In this study, we show that neutrophils secrete the collagenase MMP-8 in response to direct infection with Mycobacterium tuberculosis and via cellular networks. MMP-8 is up-regulated in respiratory samples from TB patients, driving matrix destruction associated with neutrophil activation and reflects disease severity. Neutrophils are present adjacent to the wall of TB cavities in human histology specimens. The metabolic pathway AMP-activated protein kinase (AMPK) regulates neutrophil MMP-8 secretion with data supported by studies in human neutrophils from AMPK-deficient patients. Host-directed therapy against neutrophil MMP-8 may reduce innate-immune mediated tissue damage in TB.

Salmonella bacteremia can be complicated by mycotic aneurysm with the potential for a catastrophic presentation. Treatment involves prompt surgery with debridement, extraanatomic bypass, and prolonged antibiotic therapy. Any relapse tends to occur within the 1st year after surgery. We describe a case of Salmonella enteritidis mycotic aneurysm in a 56-year-old man 5 years after the initial presentation, emphasizing the importance of aggressive initial therapy and long-term surveillance.

Resonance Raman microspectroscopy has been applied to study normal and Plasmodium berghei-infected mouse erythrocytes. The spectra of these two types of samples can be distinguished by the CaNCa deformation mode band at 747 cm−1 for the normal erythrocytes and at 754 cm−1 for the infected erythrocytes. It is believed that this difference in the spectra is due to the presence of haemozoin in the parasite, as a result of the polymerization of haem. The spectra obtained for the normal erythrocytes are due to the porphyrin group in the haemoglobin, whereas the spectra for the infected erythrocytes are due to those in the haemozoin. The spectral difference between the normal and infected erythrocytes enables us to identify the infected cells in the trophozoite or schizont stage from the normal cells. When the normal erythrocytes are subjected to high laser power, photoreduction of the sample occurs, and the spectra of these erythrocytes correspond to the spectra of deoxy Hb.

The substantia nigra of the rostral mid-brain of a monkey was studied using Raman microspectroscopy. The white and grey matter could be clearly distinguished and their relative proportions evaluated from the Raman peaks in the 3000 cm−1 region. Raman spectra obtained from the substantia nigra for both treated and untreated samples showed that the process of staining the neuron nuclei affected the brain cells and the quality of the Raman spectra from the treated samples was poorer. The brain cells of a monkey suffering from Parkinson's disease was also studied. Raman spectra collected from the control cells and the diseased cells did not show a clear difference. Copyright © 1999 John Wiley & Sons, Ltd.

The Raman spectra of lithium metavanadate, LiVO 3 , have been recorded in the temperature range 300-10 K. A phase transition was observed at about 70 K. A soft mode was found for the room temperature phase at 55 cm −1 , while at least two soft modes were observed for the low temperature phase at 213 and 289 cm −1 respectively. The hydrated samples LiVO 3 ·2H 2 O were also studied. It was found that the samples grown from supersaturated aqueous solutions contained only water molecules adsorbed on the crystal surface and these can be eliminated by heating to 70°C, while the samples grown from unsaturated solution have water molecules inside the sample as well as on the surface, and a higher temperature of 130°C is needed to release the internal water. The hydrated samples may transform to LiVO 3 through an intermediate phase.

Sodium metavanadates in α (α-NaVO3), β (β-NaVO3) and hydrated (NaVO3 · 2H2O) forms were studied down to 10 K. All the phases were found to be stable at low temperatures. The hydrated to β transformation above room temperature was found to occur at 305 K. This transition is first order and most likely a one-step process, rather than a two-step process as had been suggested previously.

Lithium metavanadate (LiVO3) single crystals have been studied by Raman spectroscopy under high pressure up to 200 kbar. Three phase transitions were observed and they are believed to be a series of transitions involving the breaking up of the infinite VO4- chains into VO3- ions of average symmetry C3 nu . On decompression, the LiVO3 transforms into an amorphous phase instead of reverting to the ambient crystalline phase, similarly to what has been observed for alpha -NaVO3. The difference in the behaviours between LiVO3 and alpha -NaVO3 on compression has been explained by the different sizes of the Li+ and Na+ ions. The restoration of the virgin crystalline phase and the relinking of the VO4- chains were observed after heating the reclaimed samples.

In an earlier study, we showed that alpha -NaVO3 undergoes a crystalline-amorphous phase transition at approximately 60 kbar. Below the amorphization pressure, some spectral changes were observed in the Raman spectra, but due to the polycrystalline nature of the samples used in these experiments, these changes were not clearly demonstrated. Here we report on high-pressure studies of alpha -NaVO3 using single-crystal samples in the pressure range below 60 kbar. A first-order crystalline-crystalline phase transition occurred at 43 kbar. The transition was marked by the appearance of new Raman bands in both the internal and external vibrational regions, and the single-crystal sample shattered after the transition. Continuous spectral changes were observed for the Raman bands associated with the rocking, wagging and twisting motions preceding the transition.

Pressure-induced amorphization has been the subject of intense study for the past few years because of its importance in materials science and solid state physics. We reported a crystalline-amorphous phase transition at c . 60 kbar in NaVO 3 [Shen et al., Phys. Rev. B 49 , 1433 (1994)], which is the lowest pressure found for such transitions in ionic crystals. Here we report on the details of the transitional region and the re-linking of the VO 4 chains upon heating.

In an earlier study, the α-phase, which is one of the stable forms of NaVO3 under ambient conditions, has been shown to undergo a crystalline-amorphous phase transition at c. 60kbar [Shen el at., J. Phys. Chem. Solids 55, 665 (1994)]. In the amorphous phase, the chains consisting of corner-sharing VO4 tetrahedra break up into individual VO3 pyramids. We now report on the high pressure study of the β-form, for which three phase transitions have been found. The first transition at 14 kbar is of first order and involves major structural changes. The second at about 44 kbar is second order and only subtle spectral changes are seen. The third is at 80 kbar and the sample may be partially disordered in this phase. Most importantly, despite the fact that both the α- and β-forms are stable phases of NaVO3 under ambient conditions, their difference persists to very high pressure, and no amorphous phase is observed up to 166 kbar in β -NaVO3.