http://nova.newcastle.edu.au/vital/access/services/Feed ${session.getAttribute("locale")} 5 http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:12377 Background: There has been increasing interest in small intestinal bacterial overgrowth (SIBO) after reports of a link with irritable bowel syndrome (IBS), yet our understanding of this entity is limited. Aim: Our aim was to estimate the yield of patients undergoing duodenal aspirate culture, and to identify symptoms and features that predict SIBO. Methods: A medical chart review of patients who had undergone duodenal aspirate culture at an academic medical centre in 2003 was performed to record clinical characteristics and culture results. The associations between aspirate results and symptoms, medical diagnoses and medication use were assessed using logistic regression. Results: A total of 675 patients had available aspirate results. Mean age of the sample was 53 (s.d. 17) and 443 (66%) were female patients. Overall, 8% of aspirates were positive for SIBO; 2% of IBS patients had SIBO. Older age, steatorrhoea and narcotic use were associated with SIBO (P < 0.05). PPI use was not associated with SIBO, but was associated with bacterial growth not meeting criteria for SIBO (P < 0.05). Inflammatory bowel disease (IBD), small bowel diverticula and pancreatitis were positively associated with an abnormal duodenal aspirate (P < 0.05), but other conditions including IBS were not associated with SIBO. Conclusion: Older age, steatorrhoea, narcotic use, IBD, small bowel diverticula and pancreatitis were associated with small intestinal bacterial overgrowth based on abnormal duodenal aspirate culture results. However, no clear associations of true small intestinal bacterial overgrowth with IBS or PPI use were detected, in contrast to recent speculation. 2013-01-09T04:50:03.958Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:11074 The synthesis of RNA is highly regulated at all stages by transcription factors. As an essential transcription elongation factor, NusA has been studied biochemically for more than 30 years. However, until now no structural information has been available on NusA-RNAP complexes and the NusA interaction site on RNAP was a point of speculation. Determination of the structure of RNA polymerase in complex with NusA is helping us understand how NusA regulates transcription. The resulting model of RNA polymerase in complex with NusA has shed light on the transition from the initiation to elongation stages of transcription, and how NusA functions in promoting regulatory pausing and termination. 2012-07-12T03:30:03.672Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:10634 There are three stages of transcription: initiation, elongation and termination, and traditionally there has been a clear distinction between the stages. The specificity factor sigma is completely released from bacterial RNA polymerase after initiation, and then recycled for another round of transcription. Elongation factors then associate with the polymerase followed by termination factors (where necessary). These factors dissociate prior to initiation of a new round of transcription. However, there is growing evidence suggesting that sigma factors can be retained in the elongation complex. The structure of bacterial RNAP in complex with an essential elongation factor NusA has recently been published, which suggested rather than competing for the major σ binding site, NusA binds to a discrete region on RNAP. A model was proposed to help explain the way in which both factors could be associated with RNAP during the transition from transcription initiation to elongation. 2012-04-12T05:59:55.195Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:9634 The aims of this study were to examine long-term growth interactions of five probiotic strains (Lactobacillus casei 01, Lactobacillus plantarum HA8, Lactobacillus rhamnosus GG, Lactobacillus reuteri ATCC 55730 and Bifidobacterium lactis Bb12) either alone or in combination with Propionibacterium jensenii 702 in a co-culture system and to determine their adhesion ability to human colon adenocarcinoma cell line Caco-2. Growth patterns of probiotic Lactobacillus strains were not considerably affected by the presence of P. jensenii 702, whereas lactobacilli exerted a strong antagonistic action against P. jensenii 702. In the co-culture of Bif. lactis Bb12 and P. jensenii 702, a significant synergistic influence on growth of both bacteria was observed (P < 0.05). The results of adhesion assay showed that when probiotic strains were tested in combination, there was evidence of an associated effect on percentage adherence. However, in most cases these differences were not statistically significant (P < 0.05). Adhesion percentage of Lb. casei 01 and Lb. rhamnosus GG both decreased significantly in the presence of P. jensenii 702 compared to their adhesion levels when alone (P < 0.05). These results show that the survival and percentage adhesion of some probiotic strains may be influenced by the presence of other strains and this should be considered when formulating in the probiotic products. 2011-12-07T02:00:13.319Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1343 Recent research in rodents has demonstrated that exposure to bacterial endotoxin during the neonatal period alters the development of the hypothalamic-pituitary-adrenal axis resulting in hypersecretion of corticosterone after stress-exposure in adulthood. Given the known interactions between glucocorticoids and the immune system it was hypothesized that such alterations may impact on immune outcomes. Fischer 344 rats were treated with endotoxin (50 [mu]g/kg Salmonella enteritidis, i.p.) or the vehicle on postpartum d 1, 3, 5, and 7. In adulthood, animals were subjected to chronic stress (6 x 10 h/d restraint stress), and the effect on resistance to tumor colonization (experiment 1) and natural killer cell activity (experiment 2) was assessed. Experiment 3 assessed corticosterone responses to acute stress in adulthood after neonatal endotoxin or saline treatment. Neonatal endotoxin exposure resulted in a 2-fold increase in tumor colonization (p < 0.001) and a significant impairment in the activity of natural killer cells (p < 0.01), cells critically involved in the surveillance and eradication of tumor cells. Neonatal endotoxin exposure also resulted in a significant decrease in gain weight that persisted into adulthood (p < 0.05), and potentiation of corticosterone responses to acute stress in adulthood (p < 0.05). We conclude that neonatal endotoxin exposure produces long-term changes in the hypothalamic-pituitary-adrenal axis, and has significant long-term effects on immune function, specifically in terms of resistance to tumor colonization in adulthood. 2010-04-27T06:54:22.013Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1221 The microbiological and chemical quality of tank-stored rainwater is impacted directly by roof catchment and subsequent run-off contamination, via direct depositions by birds and small mammals, decay of accumulated organic debris, and atmospheric deposition of airborne micro-organisms and chemical pollutants. Previous literature reports on roof water quality have given little consideration to the relative significance of airborne micro-organisms. This study involved analyses of direct roof run-off at an urban housing development in Newcastle, on the east coast of Australia. A total of 77 samples were collected during 11 separate rainfall events, and microbial counts and mean concentrations of several ionic contaminants were matched to climatic data corresponding to each of the monitored events. Conditions both antecedent to, and those prevailing during each event, were examined to investigate the influence of certain meteorological parameters on the bacterial composition of the roof water and indirectly assess the relative contribution of airborne micro-organisms to the total bacterial load. Results indicated that airborne micro-organisms represented a significant contribution to the bacterial load of roof water at this site, and that the overall contaminant load was influenced by wind velocities, while the profile (composition) of the load varied with wind direction. The implications of these findings to the issues of tank water quality and health risk analysis, appropriate usage and system design are discussed. 2010-04-27T06:39:15.427Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1852 Introduced pathogens from faecal material can make their way into the aquatic environment from a number of catchment sources. These sources typically include sewage outfalls, seepage from septic tanks, and urban and agricultural runoff. Shellfish as filter feeders are particularly susceptible to contamination in faecally contaminated waters and a range of microbiological indicators have been developed to assess the levels of contamination and likely risks to public health (Hackney and Pierson, 1994). This paper outlines the application of bacterial source tracking (BST) in a shellfish growing area in part of the Port Stephens estuary along the NSW north coast. The approach is based on the premise that bacterial isolates from different faecal sources will have significantly different resistance patterns to the battery of antibiotics and concentrations tested. Faecal streptococci (FS) were isolated from several possible faecal sources: beef and dairy cattle, chickens and humans. The resistance patterns of these isolates to four different concentrations of four antibiotics were compared to those of FS isolates obtained from samples collected upstream and in the vicinity of the oyster leases. Discriminant analysis was performed using the patterns from the known source isolates and the rate of correct classification was determined for each source. The predictive function of discriminant analysis was then used to determine the most probable source of each of the unknown isolates from Tilligerry Creek, the drainage channels to the estuary, and the shellfish leases. Preliminary results are presented here and suggest that there is no single significant source of faecal contamination, rather there are contributions from a range of sources. The findings may have implications for the ways in which land use activities and catchments are managed in similar estuarine locations with a shellfish industry. 2010-04-27T06:35:27.424Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:1519 Aim: To assess whether there is any association between membrane damaging toxin production by Staphylococcus spp. and self-reported TMD symptom expression in a group of patients selected to have CFS. Methods: Thirty-three defined Chronic Fatigue Syndrome (CFS) patients and 33 ageand sex-matched controls were assessed to evaluate the relationship between carriage of membrane damaging toxin producing staphylococcus, CFS and temporomandibular dysfunction (TMD) symptoms. Results: The CFS patients had an increased prevalence of face pain (Odds Ratio = 21.0, 95% CL 4.2-106, P < .001) and temporomandibular joint (TMJ) clicking/locking (OR = 5.7, 95% CL 1.423.5, P < .007), and the coagulase-negative staphylococcus maximum% B*-toxin haemolysis per patient. Both multivariate and univariate analyses revealed an association between the membrane damaging o*-toxin producing CoNS (MDT-CoNS) species per subject and face pain prevalence and intensity within both the CFS patients and the control subjects. No association was found between CoNS toxin production and TMJ clicking/locking. Importantly, áand B*-toxin production by CoNS was associated with patient reporting of arthritis. Conclusions: These data confirm the original observations of the association between MDTCoNS and facial muscle pain (Butt et al, 1998; McGregor et al, 2003). These data also suggest that MDT-CoNS associated facial muscle pain expression represents a distinct clinical entity, which has an increased prevalence in CFS patients. 2010-04-27T06:29:06.763Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:4347 Background: Rhinovirus infection is responsible for considerable morbidity and mortality as the major cause of exacerbations of asthma, and is also known to induce exacerbations of cystic fibrosis and chronic obstructive pulmonary disease. Exacerbations of these diseases are also frequently associated with bacterial and atypical bacterial infection. Alveolar macrophages are the major immune cells in the airways and are important in defence against bacterial infections. Methods: The authors investigated whether rhinovirus modifies cytokine release, the pattern recognition receptor expression and phagocytosis by human alveolar macrophages in response to bacterial products. Results: Viable rhinovirus was detected in macrophages up to 3 days after exposure and viral RNA expression persisted for 10 days. Infectious but not UV inactivated rhinovirus increased tumour necrosis factor α (TNFα) and interleukin (IL)8 release by macrophages. In contrast, infectious rhinovirus impaired lipopolysaccharide and lipoteichoic acid induced TNFα and IL8 secretion by macrophages. Rhinovirus induced impairment of macrophage antibacterial immune responses did not involve IL10, prostaglandin E₂or downregulation of Toll-like receptor 2. Furthermore, the macrophage phagocytic response to labelled bacterial particles, but not to latex beads, was impaired. Conclusion: The authors have identified impairment of cytokine responses to bacterial lipopolysaccharide and lipoteichoic acid by alveolar macrophages in response to infectious rhinovirus. Virus induced impairment of antibacterial host defence has important implications in the pathogenesis of exacerbations of respiratory diseases. 2010-04-27T05:04:33.626Z ]]> http://nova.newcastle.edu.au/vital/access/manager/Repository/uon:5667 The report by M A Weber and colleagues (May 31, p 1848) supports many previous studies in which Staphylococcus aureus and gram negative organisms were isolated from infants who died suddenly and unexpectedly. S aureus best fits predictions of the bacterial toxin hypothesis of sudden unexpected death in infancy. There are research groups with specialist techniques for detection of various bacterial toxins and the host’s response to them; co-operative studies between these groups with clinical teams such as that at Great Ormond Street could provide significant insights into the role of infectious agents and inflammation in SUDI. 2010-04-27T04:38:29.691Z ]]>