Industrial tomography (XCT) is a nondestructive test method that provides information about spatial distribution of X-ray absorption in the analyzed structures. The aim of this paper was to examine the possibility and accuracy of application of XCT method for discontinuity and porosity detection in parts made of 316L stainless steel powder produced by Selective Laser Melting technology. Analysis conducted on three produced test samples showed that the application of XCT as a method of quality control of specimens produced with an additive manufacturing technology offers a wide range of possibilities to detect porosity within materials. Parameters such as the amount of porosity, pore size and pore shape are presented. Accuracy of XCT method strongly depends on the size of the samples analyzed, but the possibility of obtaining information in 3D nondestructively shows considerable advantages of XCT method over traditional metallographic cross-sectional analysis

No abstract

Objective The aims of the study were to analyse the surgical site infections (SSIs) in patients operated at an orthopaedic ward and to describe the drug-resistance of the aetiology of those infections. Also, analyse the possibility of SSI control through microbiological surveillance. Additionally, we have studied the information inferred by aggregating cumulative antibiograms for the SSIs of the studied orthopaedic unit. Design Cross-sectional studies carried out in 2013–2015. Setting and patients Orthopaedic and Trauma Surgery Unit in Sosnowiec, Poland; 5995 patients, 5239 operations. Methods Retrospective laboratory-based data collection study of surgical site infections. Results SSI incidence rate was 6.6%, in the implantations—hip prosthesis 5.8% and knee prosthesis 5.4%, about 6 times higher compared with European HAI-Net. SSIs were usually caused by Gram-positive bacteria (56%). The prevalence of MDR microorganisms was 22.6%, and mainly concerned the Gram-negative bacilli: 97.6% of Acinetobacter baumannii and 50.0% of Klebsiella pneumoniae were multidrug-resistant. On the basis of what the Formula for Rational Empiric Antimicrobial Therapy analysis has shown, the use of amikacin, imipenem and ciprofloxacin has been recommended as the most efficient in the empirical therapy of SSIs. Conclusions The infection control was a significant problem at the studied orthopaedic unit, as evidenced by the SSI incidence rate significantly higher than expected. We suggest implementing the infection control and prevention based on evidence-based medicine, and a unit-based surveillance. A cumulative unit-based antibiogram reflects the drug-susceptibility pattern for the strains from the infections acquired at the unit.

The objectives of the present study were to investigate the carbapenemase and metallo-beta-lactamase genes of Acinetobacter baumannii clinical isolates by polymerase chain reaction (PCR) and real time PCR and to determine the molecular epidemiology of the strains using the DiversiLab tool. From these data, correlations between drug resistance, resistance genes, and epidemiological clones may be revealed. The study was conducted on 125 A. baumannii collected over the 2013 year. The majority of the isolates from both intensive care unit (ICU) and non-ICU cases originated from pneumonia infections (79.2%), isolates from blood infections accounted for 17.6% and 3.2% were from meningitis infections. In the ICU cases compared with the non-ICU cases, bloodstream infections were more frequently diagnosed (19.2% vs. 11.5%). Sixty percent of A. baumannii strains were resistant to all the antimicrobials tested with the exception of colistin. All strains were susceptible to colistin and polymyxin B. Extensively drug-resistant (XDR) strains accounted for 80.8% of the isolates tested and these XDR strains were more frequently isolated from ICU cases than from non-ICU cases (93.9% vs. 30.8%). Among the 101 isolates of A. baumannii exhibiting the XDR pattern of resistance, 80 possessed the blaOXA-24 gene and 29 had the blaOXA-23 gene. Only two isolates possessed the blaVIM gene. The presence of the ISAba1element was confirmed among 10 strains from patients hospitalized in the ICU. Using repetitive extragenic palindromic sequence PCR (DiversiLab typing), six clones and 12 unique strains were identified, of which two clones dominated. Most isolates belonging to clone 1 (66.7%) and clone 2 (85.5%) were susceptible only to colistin. In summary, it is clear from our findings and those of other studies that carbapenem resistance among A. baumannii strains presents a serious clinical problem worldwide. Furthermore, the presence of XDR international clone II in ICUs poses a potential risk for future outbreaks of A. baumannii infection and controlling A. baumannii infections in hospitals presents a serious challenge.

Bone infections are a significant public health burden associated with morbidity and mortality in patients. Microbial biofilm pathogens are the causative agents in chronic osteomyelitis. Research on the pathogenesis of osteomyelitis has focused on indirect bone destruction by host immune cells and cytokines secondary to microbial insult. Direct bone resorption by biofilm pathogens has not yet been seriously considered. In this study, common osteomyelitis pathogens (Staphylococcus aureus, Pseudomonas aeruginosa, Candida albicans, and Streptococcus mutans) were grown as biofilms in multiple in vitro and ex vivo experiments to analyze quantitative and qualitative aspects of bone destruction during infection. Pathogens were grown as single or mixed species biofilms on the following substrates: hydroxyapatite, rat jawbone, or polystyrene wells, and in various media. Biofilm growth was evaluated by scanning electron microscopy and pH levels were monitored over time. Histomorphologic and quantitative effects of biofilms on tested substrates were analyzed by microcomputed tomography and quantitative cultures. All tested biofilms demonstrated significant damage to bone. Scanning electron microscopy indicated that all strains formed mature biofilms within 7 days on all substrate surfaces regardless of media. Experimental conditions impacted pH levels, although this had no impact on biofilm growth or bone destruction. Presence of biofilm led to bone dissolution with a decrease of total volume by 20.17±2.93% upon microcomputed tomography analysis, which was statistically significant as compared to controls (p <0.05, ANOVA). Quantitative cultures indicated that media and substrate did not impact biofilm formation (Kruskall-Wallis test, post-hoc Dunne’s test; p <0.05). Overall, these results indicate that biofilms associated with osteomyelitis have the ability to directly resorb bone. These findings should lead to a more complete understanding of the etiopathogenesis of osteomyelitis, where direct bone resorption by biofilm is considered in addition to the well-known osteoclastic and host cell destruction of bone.