The modA10 phasevarion of nontypeable Haemophilus influenzae R2866 regulates multiple virulence-associated traits.

Non-typeable Haemophilus influenzae (NTHi) is a human restricted commensal and pathogen that elicits inflammation by adhering to and invading airway epithelia cells: transcytosis across these cells can result in systemic infection. NTHi strain R2866 was isolated from the blood of a normal 30-month old infant with meningitis, and is unusual for NTHi in that it is able to cause systemic infection. Strain R2866 is able to replicate in normal human serum due to expression of lgtC which mimics human blood group p(k). R2866 contains a phase-variable DNA methyltransferase, modA10 which switches ON and OFF randomly and reversibly due to polymerase slippage over a long tetrameric repeat tract located in its open reading frame. Random gain or loss of repeats during replication can results in expressed (ON), or not expressed (OFF) states, the latter due to a frameshift or transcriptional termination at a premature stop codon. We sought to determine if the unusual virulence of R2866 was modified by modA10 phase-variation. A modA10 knockout mutant was found to have increased adherence to, and invasion of, human ear and airway monolayers in culture, and increased invasion and transcytosis of polarized human bronchial epithelial cells. Intriguingly, the rate of bacteremia was lower in the infant rat model of infection than a wild-type R2866 strain, but the fatality rate was greater. Transcriptional analysis comparing the modA10 knockout to the R2866 wild-type parent strain showed increased expression of genes in the modA10 knockout whose products mediate cellular adherence. We conclude that loss of ModA10 function in strain R2866 enhances colonization and invasion by increasing expression of genes that allow for increased adherence, which can contribute to the increased virulence of this strain.

Diet diversity and environment determine the intestinal microbiome and bacterial pathogen load of fire salamanders.

Diverse communities of symbiotic microbes inhabit the digestive systems of vertebrates and play a crucial role in animal health, and host diet plays a major role in shaping the composition and diversity of these communities. Here, we characterized diet and gut microbiome of fire salamander populations from three Belgian forests. We carried out DNA metabarcoding on fecal samples, targeting eukaryotic 18S rRNA of potential dietary prey items, and bacterial 16S rRNA of the concomitant gut microbiome. Our results demonstrated an abundance of soft-bodied prey in the diet of fire salamanders, and a significant difference in the diet composition between males and females. This sex-dependent effect on diet was also reflected in the gut microbiome diversity, which is higher in males than female animals. Proximity to human activities was associated with increased intestinal pathogen loads. Collectively, the data supports a relationship between diet, environment and intestinal microbiome in fire salamanders, with potential health implications.

Factors influencing length of stay following primary total knee replacement in a UK specialist orthopaedic centre.

AIM: To identify factors significant in influencing LOS following primary TKA in a UK specialist arthroplasty centre. METHOD: We retrospectively reviewed factors affecting LOS of 514 patients who underwent primary TKA in a single specialist arthroplasty centre in the UK over a one-year period. Surgical and patient factors that may influence LOS were recorded. RESULTS: The median LOS was 5days. 85% were discharged within 10days. Those staying longer were classified as long stay (up to 3months). The only surgical factor that influenced length of stay was postoperative blood transfusion (p<0.0001). Females stayed longer as did those who lived in more deprived areas. These factors did not remain significant in multivariate analysis. The other most significant predictors at multivariate analysis were pre-operative patient factors such as poor anaesthetic fitness (ASA3 and ASA4) (p=0.001), BMI=30-35 (p=0.04), BMI>35 (p=0.009) and age>80 (p=0.01). CONCLUSION: Length of stay is largely due to case mix and this should be considered when planning a local arthroplasty service. LEVEL OF EVIDENCE: 2-II.

Lower thoracic spinal cord injury without radiographic abnormality in an amateur rugby player.

A 37-year-old man, amateur rugby player sustained a hyperextension injury to his lower thoracic spine during a scrum collapse. The patient developed extreme hyperpathia in the T10-12 dermatome, and parasthesia from T12 to S1 in the left lower limb. Medical Research Council grade 5 power was regained rapidly within minutes of the accident, and the hyperpathia resolved within a week. MRI showed contusion of the spinal cord at T10 level but no associated osseoligamentous injury. Six months later, parasthesia and subjective weakness remained in the left lower limb. To our knowledge, this is the first description of a lower thoracic spinal cord injury without radiographic abnormality following an isolated low-energy injury in a skeletally mature patient.

Informed consent in trauma: does written information improve patient recall of risks? A prospective randomised study.

Informed consent is vital to good surgical practice. Pain, sedative medication and psychological distress resulting from trauma are likely to adversely affect a patient's ability to understand and retain information thus impairing the quality of the consent process. This study aims to assess whether provision of written information improves trauma patient's recall of the risks associated with their surgery. 121 consecutive trauma patients were randomised to receive structured verbal information or structured verbal information with the addition of supplementary written information at the time of obtaining consent for their surgery. Patients were followed up post-operatively (mean 3.2 days) with a questionnaire to assess recall of risks discussed during the consent interview and satisfaction with the consent process. Recall of risks discussed in the consent interview was found to be significantly improved in the group receiving written and verbal information compared to verbal information alone (mean questionnaire score 41% vs. 64%), p=0.0014 using the Mann-Whitney U test. Patient satisfaction with the consent process was improved in the group receiving written and verbal information and 90% of patients in both groups expressed a preference for both written and verbal information compared to verbal information alone. Patients awaiting surgery following trauma can pose a challenge to adequately inform about benefits conferred, the likely post operative course and potential risks. Written information is a simple and cost-effective means to improve the consent process and was popular with patients.