Freezing cold injuries among soldiers in the Norwegian Armed Forces - A cross sectional study.

INTRODUCTION: Freezing cold injuries (FCI) are a common risk in extreme cold weather warfare operations. The Norwegian Armed Forces (NAF) have the expertise and capabilities in education and training for warfighting capabilities in the Arctic. Nevertheless, a substantial number of Norwegian soldiers sustain freezing cold injuries annually. The aim of this study was to describe the FCI in the NAF, the associated risk factors and clinical associations. METHODOLOGY: The subjects for the study were soldiers registered with FCI in the Norwegian Armed Forces Health Registry (NAFHR) between January 1st 2004-July1st 2021. The soldiers answered a questionnaire regarding background, activities at the time of injury, description of the FCI, risk factors, medical treatment and any sequelae from their FCI. RESULTS: FCI in the NAF were most frequently reported among young conscripts (mean20.5 years). Hands and feet are most often injured (90.9%). Only a minority (10.4%) received medical treatment. The majority (72.2%) report sequelae. Extreme weather conditions was the most important risk factor (62.5%). CONCLUSIONS: Most soldiers had the knowledge to avoid FCI, but they were injured anyway. It is concerning that only one in 10 injured soldiers received medical treatment after diagnosed with FCI, increasing the risk of FCI sequelae.

Highly variable effect of sonication to dislodge biofilm-embedded Staphylococcus epidermidis directly quantified by epifluorescence microscopy: an in vitro model study.

BACKGROUND: In cases of prosthetic joint infections, culture of sonication fluid can supplement culture of harvested tissue samples for correct microbial diagnosis. However, discrepant results regarding the increased sensitivity of sonication have been reported in several studies. To what degree bacteria embedded in biofilm are dislodged during the sonication process has to our knowledge not been fully elucidated. In the present in vitro study, we have evaluated the effect of sonication as a method to dislodge biofilm by quantitative microscopy. METHODS: We used a standard biofilm method to cover small steel plates with biofilm forming Staphylococcus epidermidis ATCC 35984 and carried out the sonication procedure according to clinical practice. By comparing area covered with biofilm before and after sonication with epifluorescence microscopy, the effect of sonication on biofilm removal was quantified. Two series of experiments were made, one with 24-h biofilm formation and another with 72-h biofilm formation. Confocal laser scanning microscopy (CLSM) and scanning electron microscopy (SEM) were used to confirm whether bacteria were present after sonication. In addition, quantitative bacteriology of sonication fluid was performed. RESULTS: Epifluorescence microscopy enabled visualization of biofilm before and after sonication. CLSM and SEM confirmed coccoid cells on the surface after sonication. Biofilm was dislodged in a highly variable manner. CONCLUSION: There is an unexpected high variation seen in the ability of sonication to dislodge biofilm-embedded S. epidermidis in this in vitro model.

The reality of war: wounded and fallen Norwegian soldiers in Afghanistan.

BACKGROUND: Norway has been contributing military forces to Afghanistan since 2001. The following is an overview of all combat-related injuries and deaths among Norwegian soldiers in the period from 2002 to 2010. MATERIAL AND METHOD: All medical records for Norwegian military personnel in Afghanistan in the period to January 2011 were reviewed and those who fell or were injured during combat were identified. The mechanism and anatomical region of the injury were registered and an injury severity score (ISS), revised trauma score (RTS) and probability of survival score were calculated. Deaths were classified according to military trauma terminology and were additionally assessed as either "non-survivable" or "potentially survivable". RESULTS: There were 45 injury incidents with nine deaths among 42 soldiers. The injury mechanism behind seven of the deaths was an improvised explosive device (IED). All injuries resulting in deaths were "non-survivable". Seven soldiers were severely injured. The mechanisms were bullet wounds, IED, splinters from grenades and landmine explosions. Twenty nine incidents involving 28 soldiers resulted in minor injuries. The most frequent mechanism was ricochet or splinter injury from shooting or an exploding grenade. INTERPRETATION: The majority of conflict-related injuries in Afghanistan were due to explosions. The mechanism and anatomical distribution of the injuries was the same among Norwegian soldiers as among allies. The deaths were due to extensive injuries that were non-survivable.

A comprehensive microbiological evaluation of fifty-four patients undergoing revision surgery due to prosthetic joint loosening.

The diagnosis of a chronic prosthetic joint infection (PJI) is challenging, and no consensus exists regarding how best to define the criteria required for microbiological identification. A general view is that culture of periprosthetic biopsies suffers from inadequate sensitivity. Recently, molecular analyses have been employed in some studies but the specificity of molecular analyses has been questioned, mainly due to contamination issues. In a prospective study of 54 patients undergoing revision surgery due to prosthetic joint loosening, we focused on two aspects of microbiological diagnosis of chronic PJI. First, by collecting diagnostic specimens in a highly standardized manner, we aimed at investigating the adequacy of various specimens by performing quantitative bacteriological culture. Second, we designed and performed real-time 16S rRNA gene PCR analysis with particular emphasis on minimizing the risk of false-positive PCR results. The specimens analysed included synovial fluid, periprosthetic biopsies from the joint capsule and the interface membrane, and specimens from the surface of the explanted prosthesis rendered accessible by scraping and sonication. No antibiotics were given prior to specimen collection. Based on five diagnostic criteria recently suggested, we identified 18 PJIs, all of which fulfilled the criterion of ≥2 positive cultures of periprosthetic specimens. The rate of culture-positive biopsies from the interface membrane was higher compared to specimens from the joint capsule and synovial fluid, and the interface membrane contained a higher bacterial load. Interpretational criteria were applied to differentiate a true-positive PCR from potential bacterial DNA contamination derived from the reagents used for DNA extraction and amplification. The strategy to minimize the risk of false-positive PCR results was successful as only two PCR results were false-positive out of 216 negative periprosthetic specimens. Although the PCR assays themselves were very sensitive, three patients with low bacterial numbers in periprosthetic specimens tested negative by real-time PCR. This overall lowered sensitivity is most likely due to the reduced specimen volume used for PCR analysis compared to culture and may also be due to interference from human DNA present in tissue specimens. According to the protocol in the present study, 16S rRNA gene real-time PCR did not identify more cases of septic prosthetic loosening than did culture of adequate periprosthetic biopsies.

Sonication is superior to scraping for retrieval of bacteria in biofilm on titanium and steel surfaces in vitro.

BACKGROUND AND PURPOSE: Low-virulence implant infections are characterized by bacterial colonization of the implant with subsequent biofilm formation. In these cases, soft tissue biopsies often prove to be culture negative. Consequently, detachment of the causative adherent bacteria is crucial for correct microbiological diagnosis. Using an in vitro model, we compared 4 methods of biofilm sampling from metal surfaces. METHODS: Discs of titanium and steel were incubated in the presence of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, and Propionibacterium acnes in Mueller Hinton broth. Non-adherent bacteria were removed by repeated rinsing of the discs. 10 parallels of each disc were subjected to 1 of 4 methods for bacterial recovery: (A) sonication of the discs, (B) scraping of the discs using surgical blades followed by streaking of the blades onto agar plates, (C) scraping of the discs followed by vortex mixing of the surgical blades, and (D) scraping of the discs followed by sonication of the surgical blades. Quantitative bacterial cultures were performed for each sampling method. RESULTS: With the exception of S. epidermidis on steel, sonication efficiently and reliably dislodged biofilm bacteria. The scraping methods employed did not detach bacteria embedded in biofilm. INTERPRETATION: Scraping of metal surfaces is not an adequate method for sampling of biofilm bacteria in vitro.