The bacterial aetiology of pleural empyema. A descriptive and comparative metagenomic study.

OBJECTIVES: The view of pleural empyema as a complication of bacterial pneumonia is changing because many patients lack evidence of underlying pneumonia. To further our understanding of pathophysiological mechanisms, we conducted in-depth microbiological characterization of empyemas in clinically well-characterized patients and investigated observed microbial parallels between pleural empyemas and brain abscesses. METHODS: Culture-positive and/or 16S rRNA gene PCR-positive pleural fluids were analysed using massive parallel sequencing of the 16S rRNA and rpoB genes. Clinical details were evaluated by medical record review. Comparative analysis with brain abscesses was performed using metagenomic data from a national Norwegian study. RESULTS: Sixty-four individuals with empyema were included. Thirty-seven had a well-defined microbial aetiology, while 27, all of whom had community-acquired infections, did not. In the latter subset, Fusobacterium nucleatum and/or Streptococcus intermedius was detected in 26 patients, of which 18 had additional facultative and/or anaerobic species in various combinations. For this group, there was 65.5% species overlap with brain abscesses; predisposing factors included dental infection, minor chest trauma, chronic obstructive pulmonary disease, drug abuse, alcoholism and diabetes mellitus. Altogether, massive parallel sequencing yielded 385 bacterial detections, whereas culture detected 38 (10%) and 16S rRNA gene PCR/Sanger-based sequencing detected 87 (23%). CONCLUSIONS: A subgroup of pleural empyema appears to be caused by a set of bacteria not normally considered to be involved in pneumonia. Such empyemas appear to have a similar microbial profile to oral/sinus-derived brain abscesses, supporting spread from the oral cavity, potentially haematogenously. We suggest reserving the term 'primary empyema' for these infections.

Violent trauma recidivism: Does all violence escalate?

PURPOSE: Rates of trauma patients presenting with history of prior trauma range from 25 to 44%. Outcomes involving recidivists in the setting of intentional trauma, especially penetrating trauma, are conflicting. We hypothesized that if violence does escalate with successive incidence, then injuries due to successive violence should escalate or become increasingly severe with successive admissions. METHODS: The trauma registry from an urban level I adult and pediatric trauma center was queried for injuries due to blunt assault, stabbing, and firearm injury. Primary outcome measures were mortality, injury mechanism, and injury severity for each successive trauma admission. RESULTS: Victims of blunt assault and stabbing were more likely to become recidivists than victims of gun violence (OR 1.53, p < 0.001 and OR 1.57, p < 0.001). Violent re-injury became increasingly severe only in victims of repeated gun violence. Patients with gunshot as the mechanism at every admission are at highest risk for mortality (OR 13.48, p < 0.001). All but one mortality (95.8%) in the recidivist population occurred within 180 days of discharge from a prior injury. CONCLUSION: Recidivism for interpersonal violence results in a significant number of admissions to trauma centers. In our patient cohort, injury associated with successive blunt assaults did not worsen with subsequent admissions. Recidivism for gunshot wounds tends to be more severe and have a worse prognosis with each successive admission compared to outcomes associated with repeated stab wounds. Focused efforts should include rehabilitation efforts early in the post-injury period, especially in patients with a history of gunshot wounds.

Predictors of retained hemothorax after trauma and impact on patient outcomes.

PURPOSE: Hemo/pneumothoraces are a common result of thoracic injury. Some of these injuries will be complicated by retained hemothorax (RH), which has previously been shown to be associated with longer hospitalizations. It has been proposed that early versus delayed intervention with video-assisted thoracoscopic surgery can reduce the duration of mechanical ventilation, hospital and ICU LOS, and costs in patients with RH. However, little is known regarding the effect of RH on these outcomes relative to patients with uncomplicated hemo/pneumothoraces. The aim of our study was to characterize factors present on admission that may be associated with RH and assess the impact of RH on outcomes. METHODS: A retrospective chart review was conducted and included all patients who underwent tube thoracostomy (TT) for traumatic hemo/pneumothorax admitted to a single urban adult and pediatric level I trauma center from January 2008 to September 2013. RESULTS: The study cohort included 398 patients, 17.6 % developed RH. RH was associated with significantly longer total duration of TT drainage (p < 0.001), hospital LOS (p < 0.001), and total hospital charges (p < 0.001). These associations remained significant in a subgroup analysis excluding patients with traumatic brain injury. Patients with bilateral injuries (OR 4.25, p < 0.001) and patients intubated on the day of admission (OR 2.30, p = 0.002) were significantly more likely to develop RH. There was also a small, but highly significant, association between increasing ISS and the development of RH (OR 1.07, p < 0.001). CONCLUSIONS: Our study suggests patients requiring ventilator support on admission and those with bilateral injuries are at increased risk of developing RH. Early identification of patients at risk for RH may allow for earlier intervention and potential benefits to the patient.