Potential value of a rapid syndromic multiplex PCR for the diagnosis of native and prosthetic joint infections: a real-world evidence study

Introduction: The BIOFIRE Joint Infection (JI) Panel is a diagnostic tool that uses multiplex-PCR testing to detect microorganisms in synovial fluid specimens from patients suspected of having septic arthritis (SA) on native joints or prosthetic joint infections (PJIs). Methods: A study was conducted across 34 clinical sites in 19 European and Middle Eastern countries from March 2021 to June 2022 to assess the effectiveness of the BIOFIRE JI Panel. Results: A total of 1527 samples were collected from patients suspected of SA or PJI, with an overall agreement of 88.4 % and 85 % respectively between the JI Panel and synovial fluid cultures (SFCs). The JI Panel detected more positive samples and microorganisms than SFC, with a notable difference on Staphylococcus aureus, Streptococcus species, Enterococcus faecalis, Kingella kingae, Neisseria gonorrhoeae, and anaerobic bacteria. The study found that the BIOFIRE JI Panel has a high utility in the real-world clinical setting for suspected SA and PJI, providing diagnostic results in approximately 1 h. The user experience was positive, implying a potential benefit of rapidity of results' turnover in optimising patient management strategies. Conclusion: The study suggests that the BIOFIRE JI Panel could potentially optimise patient management and antimicrobial therapy, thus highlighting its importance in the clinical setting.

Multifaceted roles of CCAR family proteins in the DNA damage response and cancer

The cell cycle apoptosis regulator (CCAR) family of proteins consists of two proteins, CCAR1 and CCAR2, that play a variety of roles in cellular physiology and pathology. These multidomain proteins are able to perform multiple interactions and functions, playing roles in processes such as stress responses, metabolism, and the DNA damage response. The evolutionary conservation of CCAR family proteins allows their study in model organisms such as Caenorhabditis elegans, where a role for CCAR in aging was revealed. This review particularly highlights the multifaceted roles of CCAR family proteins and their implications in the DNA damage response and in cancer biology.

Deep learning and single-cell phenotyping for rapid antimicrobial susceptibility detection in Escherichia coli

The rise of antimicrobial resistance (AMR) is one of the greatest public health challenges, already causing up to 1.2 million deaths annually and rising. Current culture-based turnaround times for bacterial identification in clinical samples and antimicrobial susceptibility testing (AST) are typically 18-24 h. We present a novel proof-of-concept methodological advance in susceptibility testing based on the deep-learning of single-cell specific morphological phenotypes directly associated with antimicrobial susceptibility in Escherichia coli. Our models can reliably (80% single-cell accuracy) classify untreated and treated susceptible cells for a lab-reference fully susceptible E. coli strain, across four antibiotics (ciprofloxacin, gentamicin, rifampicin and co-amoxiclav). For ciprofloxacin, we demonstrate our models reveal significant (p < 0.001) differences between bacterial cell populations affected and unaffected by antibiotic treatment, and show that given treatment with a fixed concentration of 10 mg/L over 30 min these phenotypic effects correlate with clinical susceptibility defined by established clinical breakpoints. Deploying our approach on cell populations from six E. coli strains obtained from human bloodstream infections with varying degrees of ciprofloxacin resistance and treated with a range of ciprofloxacin concentrations, we show single-cell phenotyping has the potential to provide equivalent information to growth-based AST assays, but in as little as 30 min.

Evaluation of sequence hybridization for respiratory viruses using the Twist Bioscience Respiratory Virus Research panel and the OneCodex Respiratory Virus sequence analysis workflow

Respiratory viral infections are a major global clinical problem, and rapid, cheap, scalable and agnostic diagnostic tests that capture genome-level information on viral variation are urgently needed. Metagenomic approaches would be ideal, but remain currently limited in that much of the genetic content in respiratory samples is human, and amplifying and sequencing the viral/pathogen component in an unbiased manner is challenging. PCR-based tests, including those which detect multiple pathogens, are already widely used, but do not capture information on strain-level variation; tests with larger viral repertoires are also expensive on a per-test basis. One intermediate approach is the use of large panels of viral probes or 'baits', which target or 'capture' sequences representing complete genomes amongst several different common viral pathogens; these are then amplified, sequenced and analysed with a sequence analysis workflow. Here we evaluate one such commercial bait capture method (the Twist Bioscience Respiratory Virus Research Panel) and sequence analysis workflow (OneCodex), using control (simulated) and patient samples head-to-head with a validated multiplex PCR clinical diagnostic test (BioFire FilmArray). We highlight the limited sensitivity and specificity of the joint Twist Bioscience/OneCodex approach, which are further reduced by shortening workflow times and increasing sample throughput to reduce per-sample costs. These issues with performance may be driven by aspects of both the laboratory (e.g. capacity to enrich for viruses present in low numbers), bioinformatics methods used (e.g. a limited viral reference database) and thresholds adopted for calling a virus as present or absent. As a result, this workflow would require further optimization prior to any implementation for respiratory virus characterization in a routine diagnostic healthcare setting.

A multicentre evaluation and expert recommendations of use of the newly developed BioFire Joint Infection polymerase chain reaction panel

Septic arthritis is a serious condition with significant morbidity and mortality, routinely diagnosed using culture. The FDA has recently approved the rapid molecular BioFire® Joint Infection Panel (BJIP) for synovial fluid. We aimed to evaluate the BJIP compared to culture and its potential use in patient management. A multicentre retrospective evaluation of BJIP was conducted in the UK and Ireland. Positive percent agreement (PPA) and negative percent agreement (NPA) were calculated between the BJIP and routine culture. A multidisciplinary team (MDT) discussion addressing the optimal or potential case use of the assay practice was facilitated. Three hundred ninety-nine surplus synovial fluid samples (~ 70% from native joints) from eight centres were processed using BJIP in addition to routine culture. An increased yield of positive results was detected using BJIP compared to routine culture (98 vs 83), giving an overall PPA of 91.6% and overall NPA of 93% for the BJIP compared to culture results. The BJIP detected resistant markers and additional organisms that could influence antibiotic choices including Neisseria gonorrhoeae and Kingella kingae. The MDT agreed that the assay could be used, in addition to standard methods, in adult and children patients with specialist advice use based on local needs. Rapid results from BJIP were assessed as having potential clinical impact on patient management. Organisms not included in the panel may be clinically significant and may limit the value of this test for PJI.

326 USE OF A PHARMACY PRIORITISATION TOOLKIT IN FRAIL OLDER ADULTS PRESENTING TO THE EMERGENCY DEPARTMENT

Background

A Pharmacy Prioritisation Toolkit (PPT) was adapted for use by a front door frailty multidisciplinary team to direct pharmacist review.

Methods

Over a 4-week period pharmacist referrals based on a toolkit used by the team were reviewed. Data was recorded in Excel including age, reason for referral and outcome of Medicines Optimisation Review (MOR). Pharmacy-identified patients were also analysed.

Results

Forty-Five patients were referred by the team using the PPT and 25 were pharmacist-identified for review. Reason for referral were use of high-risk medication (20/45), suspected medication related admission (9/45), chronic kidney disease or acute kidney injury (7/45), specific pharmaceutical concerns (5/45) &gt;10 regular medications (4/45). Of those reviewed, 29 MORs were made. Of patients who were pharmacist identified, 10 MORs were made (53% of patients). The toolkit was retrospectively applied to these patients and would have selected all but 3.

Conclusion

The PPT was successfully used by the team to generate 45 referrals for pharmacist review over a 4-week period. As a result of analysis of these recommendations, antimicrobial prophylaxis for urinary tract infections will be added to the high-risk medicines list on the PPT. Development of the toolkit is ongoing using a plan, do, study, act model with input from all members of the team to further improve both its efficacy and utility.

Global longitudinal strain to identify low-risk patients with suspected ACS

Funding Acknowledgements

Type of funding sources: Private grant(s) and/or Sponsorship. Main funding source(s): Albert Einstein Society

Background

Determining which chest pain presentations should be treated and considered an acute coronary syndrome/myocardial infarction (ACS/MI) versus those with non-cardiac chest pain (NCCP) can be difficult. Initial evaluation of suspected ACS requires assessment of presenting symptoms, risk factors, ECG, and cardiac biomarkers. Bedside echocardiography can assist in rapid assessment of suspected ACS through measurement of echocardiographic wall motion score index and left ventricular ejection fraction, though the sensitivity of these measurements has been called into question. Global longitudinal strain (GLS) has been associated with significant CAD and has been found to be more reproducible than LVEF. However, its utility in rapid ED evaluation of chest pain remains under-explored.

Purpose

Assess the utility of speckle-tracking strain in addition to clinical and demographic factors in identification of low-risk patients among those presenting to the ED with suspected ACS.

Methods

This was a retrospective single center study of 434 hospitalized patients aged 18 years or older in whom ACS (excluding STEMI) was suspected by ED assessment, from 9/1/2015 – 12/31/2019. Echocardiography within 24 hours of admission was analyzed, with left ventricular global longitudinal strain (LVGLS) obtained via AutoSTRAIN software (TOMTEC Imaging Systems GmbH). Patients were identified as having NCCP (n = 158, 36%), myocardial injury (n = 110, 25%), or MI (n = 166, 38%; subdivided into NSTEMI [n = 74, 44.6%] and type II MI [n = 92, 55.4%]) according to the 4th universal definition of MI. Mean strain values were compared between study groups using Independent T tests. Logistic regression and ROC analysis was done to determine the value of LVGLS in the prediction of ACS.

Results

Non-white subjects were over-represented in the NCCP group (92% vs 8%), versus the myocardial injury and MI groups (65% vs 35%, p &lt; 0.001), and on average the NCCP group was younger (56.5 ± 14.5 vs 64.8 ± 15, p &lt; 0.001). LVGLS was significantly higher for NCCP versus the MI group (17.7 ± 2.8 vs 14.9 ± 3.9, p &lt; 0.001). ROC analysis (c-statistic = 0.72) identified an optimal cutoff at ≤15.6, with sensitivity of 56% and specificity of 82%. Logistic regression analysis, including demographic and clinical variables, identified age, LVGLS, LV end-diastolic volume and serum creatinine as significant independent predictors for NCCP vs ACS. The addition of these factors in the predictive analysis resulted in slightly improved model performance (c-statistic = 0.78).

Conclusions

LVGLS among patients with suspected ACS is significantly different between NCCP and MI; however, low sensitivity for MI makes it inadequate as a single test to discriminate between the two. Combining LVGLS with other clinical/laboratory factors may have potential utility and will be explored in future work. Abstract Figure. Distribution Plot for LVGLS  Abstract Figure. ROC Curve for LVGLS

Molecular epidemiology and antimicrobial resistance phenotype of paediatric bloodstream infections caused by Gram-negative bacteria

Background

Gram-negative organisms are common causes of bloodstream infection (BSI) during the neonatal period and early childhood. Whilst several large studies have characterised these isolates in adults, equivalent data (particularly incorporating whole genome sequencing) is lacking in the paediatric population.

Methods

We perform an epidemiological and sequencing based analysis of Gram-negative bloodstream infections (327 isolates (296 successfully sequenced) from 287 patients) in children <18 years old between 2008 and 2018 in Oxfordshire, UK.

Results

Here we show that the burden of infection lies predominantly in neonates and that most infections are caused by Escherichia coli, Klebsiella spp. and Enterobacter hormaechei. There is no evidence in our setting that the proportion of antimicrobial resistant isolates is increasing in the paediatric population although we identify some evidence of sub-breakpoint increases in gentamicin resistance. The population structure of E. coli BSI isolates in neonates and children mirrors that in adults with a predominance of STs 131/95/73/69 and the same proportions of O-antigen serotypes. In most cases in our setting there is no evidence of transmission/point-source acquisition and we demonstrate the utility of whole genome sequencing to refute a previously suspected outbreak.

Conclusions

Our findings support continued use of current empirical treatment guidelines and suggest that O-antigen targeted vaccines may have a role in reducing the incidence of neonatal sepsis.

The Holistic Impact of Classroom Spaces on Learning in Specific Subjects

The Holistic Evidence and Design (HEAD) study of U.K. primary schools sought to isolate the impact of the physical design of classrooms on the learning progress of pupils aged from 5 to 11 years (U.S. kindergarten to fifth grade). One hundred fifty-three classrooms were assessed and links made to the learning of the 3,766 pupils in them. Through multilevel modeling, the role of physical design was isolated from the influences of the pupils' characteristics. This article presents analyses for the three main subjects assessed, namely, reading, writing, and math. Variations in the importance of the physical design parameters are revealed for the learning of each subject. In addition to some common factors, such as lighting, a heavy salience for Individualization in relation to math becomes apparent and the importance emerges of Connection for reading and of Links to Nature for writing. Possible explanations are suggested. These results provide a stimulus for additional finesse in practice and for further investigation by researchers.

A prospective, randomized, parallel group, controlled study of the effect of intensity of speech and language therapy on early recovery from poststroke aphasia

Objective: To examine whether the amount of speech and language therapy influences the recovery from poststroke aphasia.

Setting: A hospital stroke unit and community.

Design: A prospective, randomized controlled trial.

Intervention: Aphasic stroke patients were randomly allocated to receive 5 hours (intensive therapy group, n=51) or 2 hours (standard therapy group) of speech and language therapy per week for 12 consecutive weeks starting as soon as practicable after the stroke. Another 19 patients were recruited for 2 hours per week of therapy and were treated by National Health Service (NHS) staff (NHS group).

Outcome measure and assessment: The Western Aphasia Battery. Assessments were made blind to randomization at baseline and 4, 8, 12 and 24 weeks after the start of therapy. Data were analysed by intention to treat.

Results: The mean (SD) Western Aphasia Battery score at week 12 for the intensive, standard and NHS groups was 70.3 (26.9), 66.2 (26.2) and 58.1 (33.7), respectively. There was no treatment effect of intensive therapy (P > 0.05), but there was a statistically significant difference between the standard study and the NHS groups (P = 0.002 at week 12 and 0.01 at week 24).

Conclusions: Intensive speech and language therapy (as delivered in this study) did not improve the language impairment significantly more than the `standard' therapy which averaged 1.6 hours/week. The improvement in aphasia was least in patients who were in the NHS group. These patients received 0.57 (0.49) hours of therapy per week.

Invasive streptococcal disease: a review for clinicians

INTRODUCTION

Streptococci are a genus of Gram-positive bacteria which cause diverse human diseases. Many of these species have the potential to cause invasive infection resulting from the presence of bacteria in a normally sterile site.

SOURCES OF DATA

Original articles, reviews and guidelines.

AREAS OF AGREEMENT

Invasive infection by a streptococcus species usually causes life-threatening illness. When measured in terms of deaths, disability and cost, these infections remain an important threat to health in the UK. Overall they are becoming more frequent among the elderly and those with underlying chronic illness. New observational evidence has become available to support the use of clindamycin and intravenous immunoglobulin in invasive Group A streptococcal disease.

AREAS OF CONTROVERSY

Few interventions for the treatment and prevention of these infections have undergone rigorous evaluation in clinical trials. For example, the role of preventative strategies such as screening of pregnant women to prevent neonatal invasive Group B streptococcal disease needs to be clarified.

FUTURE PROSPECTS

Studies of invasive streptococcal disease are challenging to undertake, not least because individual hospitals treat relatively few confirmed cases. Instead clinicians and scientists must work together to build national and international networks with the aim of developing a more complete evidence base for the treatment and prevention of these devastating infections.

The clinical presentation of prosthetic joint infection

Prosthetic joint infection (PJI) complicates ∼1% of arthroplasties but accounts for considerable morbidity. Both the timing and features of PJI can vary widely. Patients may present with early (≤3 months post-operatively), delayed (3-24 months) or late disease (>24 months). They may be acutely unwell with systemic signs of sepsis or describe only a chronically painful joint with or without sinus formation. Diagnostic criteria as proposed by the Infectious Diseases Society of America and the Musculoskeletal Infection Society highlight the importance of joint sampling to obtain histological and robust microbiological evidence. Staphylococcus aureus and coagulase-negative staphylococci account for >50% of infections. Early infections are likely to have been acquired intra- or peri-operatively, whereas late infection is usually haematogenous in origin. Acute joint inflammation suggests the presence of intra-articular free-living bacteria, whereas chronic infections are associated with the formation of biofilm at the bone-cement or bone-prosthesis interface. The most significant risk factors predisposing to PJI are previous operation on the index joint, previous arthroplasty at a different site, American Society of Anesthesiologists' grade 2, 3 or 4, body mass index >25, malignancy and procedure duration <2 or >4 h.

Hepatic compartmentalization of exhausted and regulatory cells in HIV/HCV-coinfected patients

Accelerated intrahepatic hepatitis C virus (HCV) pathogenesis is likely the result of dysregulation within both the innate and adaptive immune compartments, but the exact contribution of peripheral blood and liver lymphocyte subsets remains unclear. Prolonged activation and expansion of immunoregulatory cells have been thought to play a role. We determined immune cell subset frequency in contemporaneous liver and peripheral blood samples from chronic HCV-infected and HIV/HCV-coinfected individuals. Peripheral blood mononuclear cells (PBMC) and biopsy-derived liver-infiltrating lymphocytes from 26 HIV/HCV-coinfected, 10 chronic HCV-infected and 10 HIV-infected individuals were assessed for various subsets of T and B lymphocytes, dendritic cell, natural killer (NK) cell and NK T-cell frequency by flow cytometry. CD8(+) T cells expressing the exhaustion marker PD-1 were increased in HCV-infected individuals compared with uninfected individuals (P = 0.02), and HIV coinfection enhanced this effect (P = 0.005). In the liver, regulatory CD4(+) CD25(+) Foxp3(+) T cells, as well as CD4(+) CD25(+) PD1(+) T cells, were more frequent in HIV/HCV-coinfected than in HCV-monoinfected samples (P < 0.001). HCV was associated with increased regulatory T cells, PD-1(+) T cells and decreased memory B cells, regardless of HIV infection (P ≤ 0.005 for all). Low CD8(+) expression was observed only in PD-1(+) CD8(+) T cells from HCV-infected individuals and healthy controls (P = 0.002) and was associated with enhanced expansion of exhausted CD8(+) T cells when exposed in vitro to PHA or CMV peptides. In conclusion, in HIV/HCV coinfection, ongoing HCV replication is associated with increased regulatory and exhausted T cells in the periphery and liver that may impact control of HCV. Simultaneous characterization of liver and peripheral blood highlights the disproportionate intrahepatic compartmentalization of immunoregulatory T cells, which may contribute to establishment of chronicity and hepatic fibrogenesis in HIV coinfection.

Component reductions in oxygen delivery generate variable haemodynamic and stress hormone responses

BACKGROUND

In clinical practice, global oxygen delivery (DO2) is often considered as a whole; however pathological and adaptive responses after a decrease in individual constituents of the DO2 equation (cardiac output, haemoglobin, oxyhaemoglobin saturation) are likely to be diverse. We hypothesized that an equivalent decrease in DO2 after reductions in each separate component of the equation would result in different haemodynamic, tissue oxygenation, and stress hormonal responses.

METHODS

Anaesthetized, fluid-resuscitated male Wistar rats were subjected to circulatory, anaemic, or hypoxic hypoxia (by haemorrhage, isovolaemic haemodilution, and breathing a hypoxic gas mix, respectively), produced either rapidly over 5 min or graded over 30 min, to a targeted 50% decrease in global oxygen delivery. Sham-operated animals acted as controls. Measurements were made of haemodynamics, skeletal muscle tissue oxygen tension, blood gas analysis, and circulating stress hormone levels.

RESULTS

Whereas haemorrhage generated the largest decrease in cardiac output, and the greatest stress hormone response, haemodilution had the most marked effect on arterial pressure. In contrast, rapid hypoxaemia produced a minor impact on global haemodynamics yet induced the greatest decrease in regional oxygenation. A greater degree of hyperlactataemia was observed with graded insults compared with those administered rapidly.

CONCLUSIONS

Decreasing global oxygen delivery, achieved by targeted reductions in its separate components, induces varying circulatory, tissue oxygen tension, and stress hormone responses. We conclude that not all oxygen delivery is the same; this disparity should be emphasized in classical teaching and re-evaluated in patient management.

Baseline CD4+ T-cell counts predict HBV viral kinetics to adefovir treatment in lamivudine-resistant HBV-infected patients with or without HIV infection

BACKGROUND

Coinfection with HIV and hepatitis B virus (HBV) substantially alters the course of HBV. Directly acting anti-HBV agents suppress HBV viral levels; however, the kinetics of HBV decline in mono- and coinfected persons have not been evaluated. We investigated the role of baseline CD4+ T-cell counts as a predictor of HBV response to adefovir (ADV) therapy in chronic HBV with and without HIV coinfection.

METHODS

We conducted a double-blind, randomized, placebo-controlled study of HIV-infected (n = 12) and uninfected (n = 5) chronic HBV patients treated with ADV. Five HIV uninfected patients received ADV; the HIV+ patients received ADV or placebo for a total of 48 weeks. At the end of 48 weeks, all patients received open-label ADV for an additional 48 weeks. HBV, HIV viral loads, CD4+ T-cell counts, and safety labs were performed on days 0, 1, 3, 5, 7, 10, 14, and 28 and then every 4 weeks.

RESULTS

Lower HBV slopes were observed among coinfected compared to monoinfected patients (P = .027 at 4 weeks, P = .019 at 24 weeks, and P = .045 at 48 weeks). Using a mixed model analysis, we found a significant difference between the slopes of the 2 groups at 48 weeks (P = .045). Baseline CD4+ T-cell count was the only independent predictor of HBV decline in all patients.

CONCLUSION

HIV coinfection is associated with slower HBV response to ADV. Baseline CD4+ T-cell count and not IL28B genotype is an independent predictor of HBV decline in all patients, emphasizing the role of immune status on clearance of HBV.

The value of grooming to female primates

Current socioecological models suggest that the structure of female-bonded primate groups is predicated on the need for coalitionary support in competitive interactions. Social grooming is thought to be the means by which females ensure support from other individuals, either by the direct exchange of grooming for aid or by using grooming as a means of strengthening social bonds. Since these relationships are valuable, they must be regularly serviced and must be repaired if they become damaged. We question this position and show that empirical evidence to support these theoretical arguments is lacking. We then go on to present a new framework in which the inconsistencies regarding grooming and relationship negotiation are interpreted in the context of individual decision-making processes. In this framework, primate groups represent biological markets in which individuals either trade grooming in a reciprocal manner for the direct benefits that grooming itself offers, or exchange it for tolerance by more powerful animals. A number of testable predictions are derived from this hypotheses. The need for socioecological studies to focus on the dynamics of individual relationships rather than using summary measures is emphasized since only a detailed knowledge of serial interaction will provide the key to understanding the complexities of individual decision-making processes.

Changes in CRH and ACTH synthesis during experimental and human septic shock

CONTEXT

The mechanisms of septic shock-associated adrenal insufficiency remain unclear. This study aimed at investigating the synthesis of corticotropin-releasing hormone (CRH) and vasopressin (AVP) by parvocellular neurons and the antehypophyseal expression of ACTH in human septic shock and in an experimental model of sepsis.

OBJECTIVE

To test the hypothesis that ACTH secretion is decreased secondarily to alteration of CRH or AVP synthesis, we undertook a neuropathological study of the antehypophyseal system in patients who had died from septic shock and rats with experimental faecal peritonitis.

METHODS

Brains obtained in 9 septic shock patients were compared to 10 nonseptic patients (controls). Parvocellular expression of AVP and CRH mRNA were evaluated by in situ hybridization. Antehypophyseal expression of ACTH, vasopressin V1b and CRH R1 receptors and parvocellular expression of iNOS in the PVN were evaluated by immunohistochemistry. The same experiments were carried out in a fecal peritonitis-induced model of sepsis. Data from septic rats with (n = 6) or without (n = 10) early death were compared to sham-operated (n = 8) animals.

RESULTS

In patients and rats, septic shock was associated with a decreased expression of ACTH, unchanged expression of V1B receptor, CRHR1 and AVP mRNA, and increased expression of parvocellular iNOS compared to controls. Septic shock was also characterized by an increased expression of CRH mRNA in rats but not in patients, who notably had a greater duration of septic shock.

CONCLUSION

The present study suggests that in humans and in rats, septic shock is associated with decreased ACTH synthesis that is not compensated by its two natural secretagogues, AVP and CRH. One underlying mechanism might be increased expression of iNOS in hypothalamic parvocellular neurons.

Stronger hepatitis C virus-specific CD8+ T-cell responses in HIV coinfection

Hepatitis C virus (HCV) is a widespread chronic infection that shares routes of transmission with human immunodeficiency virus (HIV). Thus, coinfection with these viruses is a relatively common and growing problem. In general, liver disease develops over years with HIV coinfection, when compared to decades in HCV monoinfection. The role of the immune system in the accelerated pathogenesis of liver disease in HIV/HCV coinfection is not clear. In this study, we compared the frequency, magnitude, breadth and specificity of peripheral blood CD4+ and CD8+ T-cell responses between HCV-monoinfected and HCV/HIV-coinfected individuals and between HIV/HCV-coinfected subgroups distinguished by anti-HCV antibody and HCV RNA status. While HIV coinfection tended to reduce the frequency and breadth of anti-HCV CD8+ T-cell responses in general, responses that were present were substantially stronger than in monoinfection. In all groups, HCV-specific CD4+ T-cell responses were rare and weak, independent of either nadir or concurrent CD4+ T-cell counts of HIV-infected individuals. Subgroup analysis demonstrated restricted breadth of CD8+ HCV-specific T-cell responses and lower B-cell counts in HIV/HCV-coinfected individuals without anti-HCV antibodies. The greatest difference between HIV/HCV-coinfected and HCV-monoinfected groups was substantially stronger HCV-specific CD8+ T-cell responses in the HIV-coinfected group, which may relate to accelerated liver disease in this setting.

Prevalence of intestinal parasitic and bacterial pathogens in diarrhoeal and non-diarroeal human stools from Vhembe district, South Africa

In the present study, a cross-sectional survey of intestinal parasitic and bacterial infections in relation to diarrhoea in Vhembe district and the antimicrobial susceptibility profiles of isolated bacterial pathogens was conducted. Stool samples were collected from 528 patients attending major public hospitals and 295 children attending two public primary schools and were analyzed by standard microbiological and parasitological techniques. Entamoeba histolytica/E. dispar (34.2%) and Cryptosporidium spp. (25.5%) were the most common parasitic causes of diarrhoea among the hospital attendees while Giardia lamblia (12.8%) was the most common cause of diarrhoea among the primary school children (p < 0.05). Schistosoma mansoni (14.4%) was more common in non-diarrhoeal samples at both hospitals (16.9%) and schools (17.6%). Campylobacter spp. (24.9%), Aeromonas spp. (20.8%), and Shigella spp. (8.5%) were the most common bacterial causes of diarrhoea among the hospital attendees while Campylobacter (12.8%) and Aeromonas spp. (12.8%) were most common in diarrhoeal samples from school children. Vibrio spp. was less common (3% in the hospitals) and were all associated with diarrhoea. Antimicrobial resistance was common among the bacterial isolates but ceftriaxone (91%) and ciprofloxacin (88.6%) showed stronger activities against all the organisms. The present study has demonstrated that E. histolytica/dispar, Cryptosporidium, Giardia, and Cyclospora are common parasitic causes of diarrhoea in Vhembe district while Campylobacter spp. and Aeromonas are the most common bacterial causes of diarrhoea in Vhembe district of South Africa.

Vasopressin synthesis by the magnocellular neurons is different in the supraoptic nucleus and in the paraventricular nucleus in human and experimental septic shock

Impaired arginine vasopressin (AVP) synthesis and release by the neurohypophyseal system, which includes the neurohypophysis and magnocellular neurons of the paraventricular and supraoptic nuclei, have been postulated in septic shock, but changes in this system have never been assessed in human septic shock, and only partially experimentally. We investigated AVP synthesis and release by the neurohypophyseal system in 9 patients who died from septic shock and 10 controls, and in 20 rats with fecal peritonitis-induced sepsis and 8 sham-operation controls. Ten rats died spontaneously from septic shock, and the others were sacrificed. In patients with septic shock, as in rats that died spontaneously following sepsis induction, AVP immunohistochemical expression was decreased in the neurohypophysis and supraoptic magnocellular neurons, whereas it was increased in the paraventricular magnocellular neurons. No significant change was observed in AVP messenger RiboNucleic Acid (mRNA) expression assessed by in situ hybridization in either paraventricular or supraoptic magnocellular cells. This study shows that both in human and experimental septic shock, AVP posttranscriptional synthesis and transport are differently modified in the magnocellular neurons of the supraoptic and paraventricular nuclei. This may account for the inappropriate AVP release in septic shock and suggests that distinct pathogenic mechanisms operate in these nuclei.

Neurological disorders in a rural Western Australian population

BACKGROUND

There is limited information on the causes of neurological disorders in an Australian rural setting.

METHODS

This study reports on a prospective cohort of 160 patients (95 women and 65 men) with a mean age of 55.1 years (standard deviation 19.78 years, range 12-92 years) receiving a neurological work-up from one neurologist attending the Geraldton and Midwest region of Western Australia over a 12-month period.

RESULTS

Patients were divided into 15 diagnostic classifications. Movement disorders were the most common diagnostic classification (38 of 160 or 23.75%) and Parkinson's disease was the most common movement disorder (30 of 38 or 78.95%) with an estimated period of prevalence of 187.5 persons per 1000. Of the other neurological disorder diagnosis classifications the following number of patients per group was observed: epilepsy (27 or 16.87%); neuromuscular disorders (22 or 13.75%); multiple sclerosis (12 or 7.5%); cerebrovascular disease (10 or 6.25%); headaches (7 or 4.37%); neurodegenerative (7 or 4.37%); dementias (6 or 3.75%); memory dysfunction (6 or 3.75%); gait disorders (4 or 2.5%); vestibular syndrome (3 or 1.87%); pain syndrome (3 or 1.87%); sensory syndrome (2 or 1.25%); brain injury (1 or 0.62%) and miscellaneous (12 or 7.5%). A high number of persons having Parkinson's disease was found.

CONCLUSION

Possible risk factors for Parkinson's disease for individuals living in Geraldton and Midwest region need to be investigated. This study raises issues pertaining to the provision of services and allocation of resources in rural areas, especially for patients with Parkinson's disease.

Harnessing CD36 to rein in inflammation

Maintaining health requires a dynamic balance between the influence of pro-inflammatory and anti-inflammatory mediators. While inflammation serves an important protective role against infection, unrestrained inflammation is acutely lethal and unresolved inflammation contributes to a broad range of chronic disorders. Immunotherapy with cytokines themselves or cytokine antagonists faces strict limitations due to efficacy, safety and cost. More successful treatment of the pro-inflammatory component of chronic disorders may emerge from strategies designed to reset the balance between pro and anti-inflammatory cytokines through physiological regulatory pathways. One emerging avenue for this approach is exploitation of the link between the cell surface protein CD36 and the anti-inflammatory cytokine interleukin-10 (IL-10). Agents that increase CD36 expression and agents that directly bind to CD36 have anti-inflammatory properties that may directly relate to induction of IL-10. The immunosuppressive effects of apoptotic cells were first reported more than a decade ago and have since been tested in animal models and several clinical trials. A recent publication demonstrates that induction of IL-10 by apoptotic cells is largely dependent upon the interaction between apoptotic cells and CD36, the receptor on monocytes and macrophages for apoptotic cells. This provides a direct mechanistic link between CD36 engagement and IL-10 induction, opening up new possibilities for using CD36 ligands, agents that increase CD36 expression or a combination of both to modulate inflammation and treat, or even prevent, an important set of chronic disorders.

XMODULATION IN MICEAND MEN: IL-10 PRODUCING CELLS INBLOOD AND LYMPHOID TISSUE

Background: The human immune system provides remarkable protection from a plethora of pathogens, but can cause damage when activated for a prolonged time (as inpersistent infections) or against self (autoimmunity). Therefore, mechanisms of immune system downregulation and control are imperative. There is little data on how the immune system is controlled in healthy individuals. We recently described a novel population of white blood cells that constitutively produce the immunomodulatory cytokine interleukin-10 (IL-10). Our objective was to further delineate the distribution of these cells in human and mouse models, as well as potential triggers for interleukin-10 production in vitro. Methods: Human and animal protocols were reviewed and approved by the institutional ethics board and animal care facilities, and informed consent was obtained from all human donors. The ex vivo percentage of peripheral blood CD36^+IL-10^+ mononuclear cells was assessed by intracellular flow cytometry in 10 healthy individuals. IL-10 production after exposure to twoCD36 ligands, thrombospondin and oxidized low density lipoprotein (oxLDL) was measured at 8 hours. Peripheral blood mononuclear cells and splenocytes from BL/6 (n=5) and Balb/c (n=1) micewere assessed for CD36^+IL-10^+ cells ex vivo as well. Results: The percentage of CD36^+IL-10^+ cells in peripheral blood fromhealthy individuals ranges between 0.1% and 0.9%. The percentage was similar in mouse peripheral blood, with a range of 0.4%-1.1%. These cells were also found in mouse spleen at a higher frequency than peripherally (1.1-1.5%). Human CD36^+IL-10^+ cells have more IL-10 when exposed to thrombospondin, oxLDL. Conclusions: Our novel population of IL-10 producing cells is found not only in healthy humans, but also in lymphoid tissue and blood from pathogen free mice. This highlights the evolutionary conservation of the cell across species, and suggests an important homeostatic function. The physiologic ligands for CD36 are ubiquitous in circulation, and ourin vitro data suggests a link between CD36 ligation and IL-10 production. IL-10 is a known immune system modulator, and its production by these cells may help maintain homeostaticcontrol of the immune system.

The character of anti-HCV T cell responses differs between spontaneous and treatment-induced viral clearance s

Introduction: Hepatitis C virus (HCV) is a common infection with approximately 170 million individuals infected worldwide. The majority of exposed individuals develop chronic infection, with viral clearance being the exception to the rule. Even with antiviral therapy, only 50-75% of treated individuals become HCV RNA negative. The role of the adaptive immune response, and particularly T cells, has been well established in other viral infections but its function in HCV infection is unclear, making it difficult to develop either prophylactic or therapeutic vaccine strategies. Objectives: Compare the breadth, specificity, and magnitude of anti-HCV T cell responses in individuals who are chronically HCV-infected with those who clear HCV spontaneously or after antiviral treatment. Methods: We assessed T cell responses in 3 groups of HCV exposed individuals: 18 people who were chronically HCV infected (anti-HCV antibody and HCV RNA positive), 5 who were exposed to HCV but cleared the virus without treatment (antibody positive, RNA negative), and 17 who responded to anti-HCV treatment (antibody positive but RNA negative after treatment). CD4+ T cell responses to HCV and recall antigens were measured by standard 3H-thymidine proliferation assay, and CD8+ T cell responses were evaluated by incubating peripheral blood mononuclear cells (PBMC) overnight with 15-mer peptides spanning the entire HCV-1a genome. The number of HCV-specific interferon-gamma (IFN-g)-producing cells per million PBMC was estimated by ELISPOT. Results: Anti-HCV CD4+ T cell responses were uncommon, and of low magnitude in all groups. Responses were only to peptides in the core region. The overall breadth of the anti-HCV CD8+ response was greatest in treated responders (average 43/44 peptide pools tested positive) and least in those who failed treatment (average 11/44). All clearers had responses to the NS5 region. The magnitude of the CD8+ response tended to be highest in the treated responders, but there was no significant difference between groups. Conclusions: The character of the anti-HCV T cell response differs not just between chronic infection and clearance, but also between spontaneous versus treatment-associated HCV clearance. This suggests that it is likely a combination of T cell breadth, magnitude and specificity that results in viral clearance. Based on these results, development of therapeutic and prophylactic vaccine strategies may need to target different T cell responses.