Characterization of the salivary microbiome in patients with pancreatic cancer.

Clinical manifestations of pancreatic cancer often do not occur until the cancer has undergone metastasis, resulting in a very low survival rate. In this study, we investigated whether salivary bacterial profiles might provide useful biomarkers for early detection of pancreatic cancer. Using high-throughput sequencing of bacterial small subunit ribosomal RNA (16S rRNA) gene, we characterized the salivary microbiota of patients with pancreatic cancer and compared them to healthy patients and patients with other diseases, including pancreatic disease, non-pancreatic digestive disease/cancer and non-digestive disease/cancer. A total of 146 patients were enrolled at the UCSD Moores Cancer Center where saliva and demographic data were collected from each patient. Of these, we analyzed the salivary microbiome of 108 patients: 8 had been diagnosed with pancreatic cancer, 78 with other diseases and 22 were classified as non-diseased (healthy) controls. Bacterial 16S rRNA sequences were amplified directly from salivary DNA extractions and subjected to high-throughput sequencing (HTS). Several bacterial genera differed in abundance in patients with pancreatic cancer. We found a significantly higher ratio of Leptotrichia to Porphyromonas in the saliva of patients with pancreatic cancer than in the saliva of healthy patients or those with other disease (Kruskal-Wallis Test; P < 0.001). Leptotrichia abundances were confirmed using real-time qPCR with Leptotrichia specific primers. Similar to previous studies, we found lower relative abundances of Neisseria and Aggregatibacter in the saliva of pancreatic cancer patients, though these results were not significant at the P < 0.05 level (K-W Test; P = 0.07 and P = 0.09 respectively). However, the relative abundances of other previously identified bacterial biomarkers, e.g., Streptococcus mitis and Granulicatella adiacens, were not significantly different in the saliva of pancreatic cancer patients. Overall, this study supports the hypothesis that bacteria abundance profiles in saliva are useful biomarkers for pancreatic cancer though much larger patient studies are needed to verify their predictive utility.

Necessity of lumbar puncture in patients presenting with new onset complex febrile seizures.

INTRODUCTION: This study aims to characterize the population of patients presenting to a pediatric emergency department (ED) for a first complex febrile seizure, and subsequently assess the rate of acute bacterial meningitis (ABM) occurrence in this population. Furthermore, this study seeks to identify whether a specific subset of patients may be at lesser risk for ABM or other serious neurological disease. METHODS: This retrospective cohort study reviewed the charts of patients between the ages of 6 months to 5 years of age admitted to an ED between 2005 and 2010 for a first complex febrile seizure (CFS). The health information department generated a patient list based on admission and discharge diagnoses, which was screened for patient eligibility. Exclusion criteria included history of a complex febrile seizure, history of an afebrile seizure, trauma, or severe underlying neurological disorder. Data extracted included age, gender, relevant medical history, descriptions of seizure, treatment received, and follow-up data. Patients presenting with two short febrile seizures within 24 hours were then analyzed separately to assess health outcomes in this population. RESULTS: There were 193 patients were eligible. Lumbar puncture was performed on 136 subjects; it was significantly more likely to be performed on patients that presented with seizure focality, status epilepticus, or a need for intubation. Fourteen patients were found to have pleocytosis following white blood cell count correction, and 1 was diagnosed with ABM (0.5% [95% confidence interval: 0.0-1.5, n=193]). Forty-three patients had 2 brief febrile seizures within 24 hours. Of the 43, 17 received lumbar puncture while in the ED. None of these patients were found to have ABM or other serious neurological disease. CONCLUSION: ABM is rare in patients presenting with a first complex febrile seizure. Patients presenting only with 2 short febrile seizures within 24 hours may be less likely to have ABM, and may not require lumbar puncture without other clinical symptoms of neurological disease.

Group B Streptococcus CovR regulation modulates host immune signalling pathways to promote vaginal colonization.

Streptococcus agalactiae (Group B Streptococcus, GBS) is a frequent commensal organism of the vaginal tract of healthy women. However, GBS can transition to a pathogen in susceptible hosts, but host and microbial factors that contribute to this conversion are not well understood. GBS CovR/S (CsrR/S) is a two component regulatory system that regulates key virulence elements including adherence and toxin production. We performed global transcription profiling of human vaginal epithelial cells exposed to WT, CovR deficient, and toxin deficient strains, and observed that insufficient regulation by CovR and subsequent increased toxin production results in a drastic increase in host inflammatory responses, particularly in cytokine signalling pathways promoted by IL-8 and CXCL2. Additionally, we observed that CovR regulation impacts epithelial cell attachment and intracellular invasion. In our mouse model of GBS vaginal colonization, we further demonstrated that CovR regulation promotes vaginal persistence, as infection with a CovR deficient strainresulted in a heightened host immune response as measured by cytokine production and neutrophil activation. Using CXCr2 KO mice, we determined that this immune alteration occurs, at least in part, via signalling through the CXCL2 receptor. Taken together, we conclude that CovR is an important regulator of GBS vaginal colonization and loss of this regulatory function may contribute to the inflammatory havoc seen during the course of infection.