Campylobacter jejuni is a Gram-negative rod-shaped bacterium that commensally inhabits the intestinal tracts of livestock and birds, and which also persists in surface waters. C. jejuni is a leading cause of foodborne gastroenteritis, and these infections are sometimes associated with the development of post-infection sequelae such as Guillain-Barré Syndrome. Flagella are considered a primary virulence factor in C. jejuni, as these organelles are required for pathogenicity-related phenotypes including motility, biofilm formation, host cell interactions, and host colonization. The post-transcriptional regulator CsrA regulates the expression of the major flagellin FlaA by binding to flaA mRNA and repressing its translation. Additionally, CsrA has previously been shown to regulate 120–150 proteins involved in diverse cellular processes. The amino acid sequence of C. jejuni CsrA is significantly different from that of Escherichia coli CsrA, and no previous research has defined the amino acids of C. jejuni CsrA that are critical for RNA binding. In this study, we used in vitro SELEX to identify the consensus RNA sequence mAwGGAs to which C. jejuni CsrA binds with high affinity. We performed saturating site-directed mutagenesis on C. jejuni CsrA and assessed the regulatory activity of these mutant proteins, using a reporter system encoding the 5′ untranslated region (5′ UTR) upstream of flaA linked translationally to the C. jejuni astA gene. These assays allowed us to identify 19 amino acids that were involved in RNA binding by CsrA, with many but not all of these amino acids clustered in predicted beta strands that are involved in RNA binding by E. coli CsrA. Decreased flaA mRNA binding by mutant CsrA proteins L2A and A36V was confirmed by electrophoretic mobility shift assays. The majority of the amino acids implicated in RNA binding were conserved among diverse Campylobacter species.
Background Primary headache syndrome (PHS) patients frequently present to otolaryngologists with sinonasal complaints and diagnosis of chronic rhinosinusitis (CRS) due to symptomatic overlap. In this study, we compare demographic, subjective, and objective clinical findings of patients with PHS versus CRS. Methods We retrospectively reviewed a database of patients presenting to a single tertiary care Rhinology clinic from December 2011—July 2017. Sino-Nasal Outcome Test-22 (SNOT) scores and Lund-Kennedy endoscopy scores were obtained. Lund-MacKay CT scores were calculated, if available. Requirement of headache specialist management was compared between PHS and CRS groups. Patients with both CRS and PHS (CRScPHS) that required headache specialist management were compared to patients with CRS without PHS (CRSsPHS) and patients with PHS alone using Kruskal-Wallis analysis of variance. Receiver operating characteristic (ROC) analyses were carried out to determine significant diagnostic thresholds. Results One-hundred four PHS patients and 130 CRS patients were included. PHS patients (72.1%) were more likely than CRS patients to require headache specialist management (6.9%, p<0.0001). CRSsPHS patients had significantly higher Nasal domain scores compared to PHS patients ( p = 0.042) but not compared to CRScPHS patients ( p>0.99). CRScPHS ( p = 0.0003) and PHS ( p<0.0001) subgroups of patients had significantly higher Aural/Facial domain scores compared to CRSsPHS patients. PHS patients also had significantly higher Sleep domains scores compared to CRSsPHS patients ( p<0.0001). Both CRScPHS and CRSsPHS subgroups had significantly higher nasal endoscopy scores ( p<0.0001) and CT scores ( p = 0.04 & p<0.0001, respectively) compared to the PHS group. Aural/Facial domain score of 4, nasal endoscopy score of 4, and CT score of 2 were found to be reliable diagnostic thresholds for absence of CRS. Conclusions The SNOT-22 may be used to distinguish PHS from CRS based upon the Aural/Facial and Sleep domains. Patients with CRS have more severe Nasal domain scores and worse objective endoscopy and CT findings.
Oral and intravenous (IV) antibiotic regimens were compared in 15 children with etiologically defined osteomyelitis and/or septic arthritis. On admission all children were started on standard IV therapy; seven were changed to oral antibiotics within 72 hours and the remaining eight continued on IV therapy for four weeks. Oral antibiotic doses were adjusted to achieve a peak serum bactericidal titer of [unknown]1:8 against the patient's own pathogen. All patients were treated in hospital for four weeks; therapy continued for a minimum of six weeks or until the erythrocyte sedimentation rate (ESR) fell below 20 mm/hr. The clinical course and outcome were similar in both groups. There were no treatment failures nor any relapses during a 12-month follow-up period. This prospective study supports, with controlled data, the concept that acute skeletal infections can be safely and successfully treated with carefully monitored oral therapy.
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