Comparison of Different Methods of Semiquantitative Assessment and Subjective Scores for Retropatellar Articular Cartilage Evaluation in Advancing Osteoarthritis.

BACKGROUND: cartilage layer thickness, composition of the extracellular matrix (ECM), geometry and configuration of retropatellar cartilage partially differ significantly from those found at other locations and are essential for patellofemoral biomechanics. MATERIAL AND METHODS: 119 serial medial and lateral patella facet samples of patients undergoing implantation of a total knee endoprosthesis of areas showing mild (Group A, macroscopically ICRS Grade 1b) respectively advanced (Group B, macroscopically ICRS Grade 3a/3b) (38 each) osteoarthritis according to the histological-histochemical grading system (HHGS) were compared with 22 healthy biopsies by means of immunohistochemistry and histology investigations. We quantified our results on the gene expression of collagen type I and II and aggrecan with real-time (RT)-PCR rsp using colourimetry for proteoglycan content. The digitized images of histology and immunohistochemistry staining with Safranin O, Alcian blue, PAS, Masson Goldner, immunostaining, e.g. for collagen I and II were also analyzed with Photoshop software. RESULTS: The most significant decrease in staining intensity was revealed for Safranin-O staining in Group B at the lateral patellar facet, and the most relevant increase was for Col I staining at the same site. The lateral patella site in Group B also showed the highest increase in the ratio of expression indices for the genes Col1A1 and the reference gene following the equation 2-ΔCt with a quotient of 29.6. CONCLUSIONS: 1. Comparisons of our retropatellar cartilage analysis with femoral and tibial studies utilizing similar techniques show significant differences. 2. Cartilage layer thickness, ECM composition, geometry and configuration are essential for patellofemoral biomechanics. 3. Consequently, there is a need for diversified approaches towards retropatellar surface during TKA as well as for advanced cartilage restoration techniques.

The effect of the design of the orthosis on the axial load transmission of two flexion abduction orthoses used in treating congenital hip dysplasia.

Background: With an incidence of 2-4% in all newborns, developmental dysplasia of the hip, DDH, represents the most frequent congenital disorder of the skeletal system in Germany. The therapy options are deduced with the help of a sonography. The conservative therapy approach includes the application of flexion abduction orthoses, which lead to a development of the child's hip through abduction and flexion angle. The overall structure of the orthoses puts a strain on the axial skeleton of the children. The following work is intended to clarify what role the design of the orthoses plays in this respect. Methods: Inclusion criterion for the study was fully developed newborns without an indication of skeletal malformations with Type I hip joints according to Graf verified by ultrasound. A total of 19 newborns were recruited and included in the period 3/2013-01/2015. Two types of orthoses used in treating developmental dysplasia of the hip (Tübinger splint, Otto Bock; hip flexion abduction orthosis (Superior orthosis) according to Mittelmeier-Graf, AIDAMED e.K (Kreuz et al., 2012; Mittelmeier et al., 1998; Schmitz et al., 1999), constructions differ, were used. Force was measured with the help of three force sensors, which were even able to be integrated into these without changing the design of the orthosis. In this closed system, force transmission was measured for the duration of a fixed period of two minutes. Findings: The greatest axial force development (overall force) is in the Tübinger splint with an average force of 15.1 N (min. 0.59 N, max. 53.09 N, mean 15.1, SD 2.46). 4.09 N (min. 0.96 N, max. 20.99 N, mean 4.09, SD 0.65) resulted in the Superior orthosis. Significant correlations between body weight and resulting axial traction - on average during the entire measurement period and in movement - can be taken from the statistical analysis regarding the Tübinger splint. Such a correlation cannot be depicted for the Superior orthosis. Interpretation: The analysis of the load transmission of the examined flexion and abduction orthoses reveals differences between the models. The construct of the orthoses in itself appears to play a significant role. Long-term effects of orthosis therapy on a child's axial skeleton have not been studied to date. Furthermore, it seems reasonable to expand the test series to orthoses, the design of which is configured in a similar matter compared to the examined aids. Conclusion: This study proves that the orthotic design has an influence on the infant's axial load.

Association of Lumbar MRI Findings with Current and Future Back Pain in a Population-based Cohort Study.

STUDY DESIGN: Population-based cohort study. OBJECTIVE: We examined associations between common lumbar degenerative changes observed on magnetic resonance imaging (MRI) and present or future low back pain (LBP). SUMMARY OF BACKGROUND DATA: The association between lumbar MRI degenerative findings and LBP is unclear. Longitudinal studies are sparse. METHODS: Participants (n = 3369) from a population-based cohort study were imaged at study entry, with LBP status measured at baseline and 6-year follow-up. MRI scans were reported on for the presence of a range of MRI findings. LBP status was measured on a 0 to 10 scale. Regression models were used to estimate the cross-sectional and longitudinal associations between individual and multiple MRI findings and LBP severity. Separate longitudinal analyses were conducted for participants with and without baseline pain. RESULTS: MRI findings were present in persons with and without back pain at baseline. Higher proportions were found in older age groups. 76.4% of participants had a least one MRI finding and 8.3% had five or more different MRI findings. Cross-sectionally, most MRI findings were slightly more common in those with LBP and pain severity was slightly higher in those with MRI findings (ranging from 0.06 for high intensity zone to 0.83 for spondylolisthesis). In the longitudinal analyses, we found most MRI findings were not associated with future LBP-severity regardless of the presence or absence of baseline pain. Compared to zero MRI findings, having multiple MRI findings (five or more) was associated with mildly greater pain-severity at baseline (0.84; 0.50-1.17) and greater increase in pain-severity over 6 years in those pain free at baseline (1.21; 0.04-2.37), but not in those with baseline pain (-0.30; -0.99 to 0.38). CONCLUSION: Our study shows that the MRI degenerative findings we examined, individually or in combination, do not have clinically important associations with LBP, with almost all effects less than one unit on a 0 to 10 pain scale.Level of Evidence: 3.

Internship Experience in Orthopaedics and Traumatology and its Impact on Becoming a Specialist. / Praktisches Jahr in Orthopädie und Unfallchirurgie ­ die kollegiale Staffelstabübergabe in die Weiterbildung?

INTRODUCTION: The German practical year is the last clinical placement period during Medical School. However, it remains unclear how medical students evaluate the practical year in orthopaedics and traumatology (Orthopädie und Unfallchirurgie; O & U) and whether it has an impact on becoming an O & U specialist. METHOD: We analysed data of 146 medical students (46,7% female) who completed the placement in O & U. From the evaluation, 37 items were included in the analyses. Participants who could imagine becoming an O & U specialist (O & U-Ja) following graduation were statistically compared to those who could not (O & U-Nein). RESULTS: Overall 123 (83.7%) trainees indicated that they would like to become an O & U specialist (O & U-Ja), 18 (12.8%) negated (O & U-Nein) and 6 (4.1%) were undecided. Groups did not differ for sex and age (sex: Chi² = 2.50, p = 0.114; age: F [1.93] < 1, p = 0.764). Group differences were found for practical orientation, independency, acquisition of anamnesis and diagnostics skills and problem-solving expertise with students who could imagine becoming an O & U specialist (O & U-Ja) giving the highest ratings. DISCUSSION: Evaluations of the last medical year are essential in order to continuously improve the internship experience and to attract students towards a certain medical field and, moreover, to post-graduate specialist training. Clinics and institutions who already emphasize on the factors derived from this evaluation, or are continuously working on improvement, might be more able to attract young professionals, since personnel acquisition is starting early in the medical field.

[Frequencies of musculoskeletal symptoms and disorders in the population-based German National Cohort (GNC)]. / Häufigkeiten muskuloskelettaler Symptome und Erkrankungen in der bevölkerungsbezogenen NAKO Gesundheitsstudie.

BACKGROUND: Musculoskeletal diseases and symptoms are very common in the general population. They lead to high healthcare costs and pose a significant burden to the national economy. OBJECTIVES: Based on data from the population-based German National Cohort (GNC), frequencies of musculoskeletal symptoms and diseases are reported, including back pain, osteoporosis, osteoarthritis, and arthritis. MATERIALS AND METHODS: Data were collected from March 2014 to March 2017 in adults aged 20-75 years during the first half of the baseline survey of the GNC. The sample comprised 101,779 interviewed subjects, including 9370 subjects who underwent clinical musculoskeletal examinations. The interview included questions about specific musculoskeletal disorders. A clinical examination of the hand provided information about palpable swollen joints and pressure-sensitive joints. Resting pain of the knees and hips was also assessed by a clinical examination. Frequencies were standardized to the German standard population of the year 2011. RESULTS: Having ever been diagnosed with recurrent back pain (22.5%) or osteoarthritis (20.6%) were the most common complaints reported in the interview; osteoporosis (2.9%) and rheumatoid arthritis (1.9%) were stated more seldom. According to the hand examination, 6.0% of all participants experienced pain in at least one finger joint. Resting pain was present in at least one knee among 8.2% and in at least one hip among 5.1% of the participants as assessed during the clinical examination. Women were more likely to report musculoskeletal disorders and symptoms than men. The proportion of adults affected by musculoskeletal diseases increased strongly with age. CONCLUSION: Musculoskeletal disorders and symptoms occur frequently. The burden of complaints and diagnoses is comparable to previous population-based surveys.

The neck-shaft angle: an update on reference values and associated factors.

Background and purpose - The neck-shaft angle (NSA) is valuable for diagnostics and therapy of the hip, but current reference values derive mostly from studies on anatomic specimens, small cohorts, or are hospital-based. Moreover, associated factors such as age, sex, or anthropometric data have rarely been considered. Therefore, we determined associated factors for NSA and reassessed the historical reference values in a general adult population.Methods - NSAs on both sides of 3,226 volunteers from the population-based Study of Health in Pomerania (SHIP) were measured with MRI. SHIP drew a representative sample of the population of Pomerania (northeastern Germany). NSAs were compared with sex, age, and anthropometric data by bivariable linear regression models. Reference values were assessed by quantile regressions for 2.5th and 97.5th percentiles.Results - The mean NSA was 127° (SD 7), while men had a lower NSA than women (95% confidence interval [CI] 0.4°-1.4°). The reference range was 114°-140°. Age was inversely associated with NSA (CI -0.2 to -0.1). Body height was positively associated with the NSA, while BMI and waist circumference showed a negative association. There was no association between body weight and NSA.Interpretation - The historical lower limit of 120° might be too high, so the radiological prevalence of hip pathology might have been overestimated. The previously reported influence of age, sex, and body height on the NSA has been confirmed.

Prevalence of benign osseous lesions of the spine and association with spinal pain in the general population in whole body MRI.

BACKGROUND: Benign osseous lesions of the spine are common but precise population prevalence estimates are lacking. Our study aimed to provide the first population-based prevalence estimates and examine association with back and neck pain. MATERIALS AND METHODS: We used data from the population-based Study of Health in Pomerania (SHIP). Whole-body MRI examinations (1.5 Tesla: T1, T2, and TIRM weightings) were available from 3,259 participants. Readings of the spinal MRI images were conducted according to a standardized protocol by a single reader (JS). The intra-rater reliability was greater than Kappa values of 0.98. Pain measures included the seven-day prevalence of spine pain and neck pain, and average spine pain intensity due to spine pain during the past three months. RESULTS: We found 1,200 (36.8%) participants with at least one osseous lesion (2,080 lesions in total). Osseous lesions were less common in men than in women (35.5% vs 38.9%; P = .06). The prevalence of osseous lesions was highest at L2 in both sexes. The prevalence of osseous lesions increased with age. Up to eight osseous lesions were observed in a single subject. Hemangioma (28%), and lipoma (13%) occurred most often. Sclerosis (1.7%), aneurysmal bone cysts (0.7%), and blastoma (0.3%) were rare. Different osseous lesions occurred more often in combination with each other. The association with back or neck pain was mostly negligible. CONCLUSION: Osseous lesions are common in the general population but of no clinical relevance for spinal pain. The prevalence of osseous lesions varied strongly across different regions of the spine and was also associated with age and gender. Our population-based data offer new insights and assist in judging the relevance of osseous lesions observed on MRIs of patients.

[Mandatory Surgical Subinternship in the Final Year of Medical School - a Stepping Stone to Becoming a Surgeon?] / Chirurgisches Pflichttertial im Praktischen Jahr ­ das Sprungbrett in die chirurgische Weiterbildung?

BACKGROUND: The final year is an important time for a medical student as this is when medical knowledge is transformed into medical responsibilities. The field of surgery is firmly anchored in the educational structure as it is mandatory during the practical year of a medical student. The purpose of this paper is to identify factors that influence medical students to choose surgery after the final year of medical school. MATERIALS AND METHODS: An online survey conducted by the AG DGOU 2012 provided complete data sets from a total of 9079 participants. 184 of these had already completed their PJ compulsory sub-internship (tertiary) surgery. These were divided into four groups for analysis: decision to specialise in surgery prior to the PJ compulsory tertiary ("yes, before", JV), during the PJ compulsory ("yes, during", JW), decision against before the PJ compulsory ("no, before", NV) or during the compulsory ("no, during", NW). The total of 38 survey items were summarised for overall assessment, taking into account the decision on subject specialisation. RESULTS: 57.9% of the respondents were positive regarding the overall impression of the surgical internship during their final year. The respondents of the JW group were especially positive, having made the decision to become a surgeon, based on their internship experience during the final year in comparison to the NW group (decision against surgery). We find significant differences in all analysed items: integration into team JW/NW (p ≤ 0.003), acquisition of expertise (p ≤ 0.014), teachers (p ≤ 0.025), quality and structure of teaching (p ≤ 0.043) and overall satisfaction with the required tertial (p ≤ 0.037). CONCLUSION: In comparison to other specialities, in the field of surgery there is the option of recruiting directly within the framework of the compulsory internship. The results reveal unsatisfactory structures from a student perspective. The lack of medical care/support, the insufficient inclusion in therapeutic considerations, the lack of professional knowledge and lack of contact with the teachers are just a few key points that negatively impact the overall outcome of students' satisfaction with the compulsory tertiary education. The results of the present study should serve as motivation and contribute to the restructuring of the compulsory core of the Practical Year, which the Master Plan 2020 will entail.

Combination Drug Therapy for the Management of Low Back Pain and Sciatica: Systematic Review and Meta-Analysis.

Combining medicines may give greater pain relief and/or improved tolerability. We conducted a systematic review to investigate the effects of combination drug therapy in patients with low back pain and/or sciatica on pain, disability, and adverse events. Databases and trial registers were searched from inception to July 27, 2017, for randomized trials of (sub)acute or chronic back pain or sciatica participants that were administered combination drug therapy compared with monotherapy or placebo. Of the 27 studies included, most combinations (21 of 23) consisted of single trials. Most combinations had no or small effect on pain and disability. A clinically important difference was found in one combination, buprenorphine plus pregabalin versus buprenorphine for chronic back pain at immediate (mean difference = -23.30; 95% confidence interval = -27.68 to -18.92) and short (mean difference = -27.60; 95% confidence interval = -31.70 to -23.50) terms; however, the quality of evidence was low. There was no statistically significant increased risk of serious adverse events. When the risk of adverse events was statistically significant, it favored monotherapy or placebo. There is no clear evidence to support any combination drug therapy for the management of low back pain and sciatica due to the limited number of studies and overall low quality of evidence. Perspective: Combining medicines may give greater pain relief and/or improved tolerability compared with single-ingredient medicines. However, the lack of studies and overall low quality of evidence limit the recommendation of combination drug therapy for the management of low back pain and sciatica.

What Are the Reference Values and Associated Factors for Center-edge Angle and Alpha Angle? A Population-based Study.

BACKGROUND: The available evidence regarding normal ranges for the center-edge angle and the alpha angle derives from a few small studies, and associated factors such as sex and anthropometric factors have not been well evaluated. Knowing more about normal values for these parameters is critical, because this can inform decisions about when to perform elective hip preservation surgery. Population-level studies would provide considerable clarity on these issues, but to our knowledge, no such studies are available. QUESTIONS/PURPOSES: The purposes of this study were (1) to use MRI in patients of a population-based study to establish normal values for the alpha and center-edge angles in the normal adult hip; and (2) to determine whether age, sex, or anthropometric variables were associated with differences in these values. METHODS: We used MRI images (1.5 T) of 3226 participants of the Study of Health in Pomerania (SHIP). SHIP is a population-based study that started with 4308 participants in 1997. Participants were recruited randomly from official inhabitant data files as a stratified cluster sample of the population from a defined region in northeastern Germany. To ensure a representative epidemiologic cohort, stratification variables were sex, age, and city of residence. Between 2008 and 2012, 1094 of these participants underwent whole-body MRI with pelvic sequences in the second followup. In parallel, the next cohort, SHIP-Trend, started with the same protocol in which 2132 participants underwent MRI examination. Reference values were calculated by quantile regressions for the 2.5 and 97.5 percentiles. Associations with the demographic features sex, age, weight, height, body mass index (BMI), and waist circumference were analyzed by bivariate linear regression models. RESULTS: The mean center-edge angle was 31° (± 7°) with a corresponding calculated normal range of 17° to 45°. The mean alpha angle was 55° (± 8°) with a corresponding calculated normal range between 39° and 71°. Men (30° ± 7°) had a lower center-edge angle than women (32° ± 8°) (p < 0.001, ß = 1.4°; 95% confidence interval [CI], 0.9°-1.9°) and a higher alpha angle (57° ± 8° versus 52° ± 7°, p < 0.001, ß = 5.7°; 95% CI, 5.2°-6.3°). Moreover, a higher center-edge angle for the left side was found (33° ± 8° versus 30° ± 8°, p < 0.001, ß =3.2°; 95% CI, 3.0°-3.4°). In addition to sex, we found that age, height, waist circumference, and BMI affected both center-edge angle and alpha angle. Weight was associated with the alpha angle as well. Because of these associations, age- and sex-adjusted reference values with belonging formulas were calculated. CONCLUSIONS: The range of normal center-edge and alpha angles is quite wide. Therefore, only markedly abnormal angles may be associated with pathology. Moreover, center-edge angle and alpha angle are associated with age, sex, and anthropometric factors, which have to be taken into account for better interpretation. CLINICAL RELEVANCE: The association of abnormal radiographic values with true clinical hip pathology is tenuous at best. Assuming that a patient with an abnormal radiograph requires treatment is unwise. The clinical picture has to be substantial for therapeutic decisions.

[Quality and Satisfaction with the Surgical Medical Clerkship from a Student Perspective]. / Qualität und Zufriedenheit mit der chirurgischen Famulatur aus studentischer Sicht.

PREFACE: The surgical medical clerkship is of special importance, as the student is given the opportunity to get in touch with medical colleagues and patients for the first time, and the interest in a certain field of specialisation can be consolidated. The present study will clarify how students perceived their medical clerkship in the field of surgery. METHODS: A nationwide online survey carried out in 2012 was able to recruit 9079 participants, and contained questions about the completed curricular internships. The present evaluation contains the data of those respondents who had completed at least four weeks of internship in surgery. The following main groups were of particular interest: overall assessment, satisfaction, structure and quality of teaching, of the teachers, and the acquisition of practical skills, which were divided into 35 items. Statistical evaluation was carried out using SPSS 22.0 (IBM Corp., Armonk, USA). In addition to the descriptive statistics, the Chi² test was performed for frequencies, and univariate ANOVAs with the sub-subject factor group (satisfied, neutral, dissatisfied) were performed for the individual items. RESULTS: Overall, the data of 526 participants could be analysed. The female proportion of students was 56.7%; the average age at the time of the survey was 25 years. In all evaluated items, there were significant differences between the groups satisfied and dissatisfied. The participants of the survey who were satisfied with the overall qualification (p = 0.000), reported that they benefited with regard to the technical and didactic quality of teaching (p = 0.000), the acquisition of practical competences (p = 0.000), as well as the didactic and professional quality of teaching (p = 0.000). DISCUSSION: Little is published about the internships for students, including the medical clerkship "Famulatur". However, this information seems to be important, as the students can freely choose the subject in which the Famulatur can be completed. Thus, in this early phase of training, it is possible to recruit young academics for the department by optimising existing structures and improving the range of courses.

[Young Academics in Neuropsychological Disciplines: Factors Affecting Career Aspiration in Psychiatry, Neurology and Psychosomatic Medicine]. / Nachwuchs in der Nervenheilkunde: berufswunschprägende Faktoren in Psychiatrie, Neurologie und Psychosomatik.

OBJECTIVE: Students with specialization preferences in psychiatry, neurology, or psychosomatic medicine were retrospectively compared with regard to aspects of motivation to choose medicine as their field of study. METHODS: To identify early predictors of specialization preferences, a nationwide online survey was conducted with 9079 medical students. The statements of those with a preference for neurology, psychiatry, or psychosomatic medicine were evaluated using analysis of variance (ANOVA). RESULTS: Prospective neurologists were motivated by scientific interest variables and less by the aspects of life management. On the other hand, students with preferences for one of the psychological disciplines reported comparatively higher degrees of desire to actively provide help and of the importance of their own medical history. There were no significant differences between future psychiatrists and psychosomatic professionals. CONCLUSION: The reported motives point to thematic orientations that might be useful in the subject-specific acquisition of young academics.

[Nursing Internship Internal Medicine: Evaluation and Influences on the Attitude towards the Specialization]. / Pflegepraktikum Innere Medizin: Evaluation und Einflüsse auf die Einstellung zum Fach.

Background German medical students have to perform a nursery internship of three month duration. While this internship is widely discussed, there is a lack of student evaluation data. Objectives Here, for the first time, student evaluation of a nursery internship in internal medicine (IM) is investigated. Moreover, the question was raised, whether the early experience during this internship may influence students' attitude towards the specialty. Methods In a nation-wide online-survey, 767 German medical students (mean age 22.8 years; 58 % female) evaluated a nursery internship on an IM ward concerning integration in medical teams, teachers, structure and quality of teaching, and satisfaction. Multivariate comparisons were conducted following the question, whether students could imagine choosing IM for a clinical elective after this nursery internship. Results 71 % of the students felt well integrated in the medical team, most was learned from the nurses, and most students indicated having acquired nursing skills. Only 19 % evaluated the structure of the internship as good, and 40 % indicated that they reached the learning goals. Students who could imagine performing an IM clinical elective (52 %) gave best evaluations on all items. Conclusions A successful nursery internship can promote students' interest in the specialty of internal medicine. But, there is a strong need for improvement in structure and content, including the, to date missing, definition of learning targets, regarding this first practical experience in medical studies.

Comparative Analysis of Direct Hospital Care Costs between Aseptic and Two-Stage Septic Knee Revision.

BACKGROUND: The most common intermediate and long-term complications of total knee arthroplasty (TKA) include aseptic and septic failure of prosthetic joints. These complications cause suffering, and their management is expensive. In the future the number of revision TKA will increase, which involves a greater financial burden. Little concrete data about direct costs for aseptic and two-stage septic knee revisions with an in depth-analysis of septic explantation and implantation is available. QUESTIONS/PURPOSES: A retrospective consecutive analysis of the major partial costs involved in revision TKA for aseptic and septic failure was undertaken to compare 1) demographic and clinical characteristics, and 2) variable direct costs (from a hospital department's perspective) between patients who underwent single-stage aseptic and two-stage septic revision of TKA in a hospital providing maximum care. We separately analyze the explantation and implantation procedures in septic revision cases and identify the major cost drivers of knee revision operations. METHODS: A total of 106 consecutive patients (71 aseptic and 35 septic) was included. All direct costs of diagnosis, surgery, and treatment from the hospital department's perspective were calculated as real purchase prices. Personnel involvement was calculated in units of minutes. RESULTS: Aseptic versus septic revisions differed significantly in terms of length of hospital stay (15.2 vs. 39.9 days), number of reported secondary diagnoses (6.3 vs. 9.8) and incision-suture time (108.3 min vs. 193.2 min). The management of septic revision TKA was significantly more expensive than that of aseptic failure ($12,223.79 vs. $6,749.43) (p <.001). On the level of the separate hospitalizations the mean direct costs of explantation stage ($4,540.46) were lower than aseptic revision TKA ($6,749.43) which were again lower than those of the septic implantation stage ($7,683.33). All mean costs of stays were not comparable as they differ significantly (p <.001). Major cost drivers were the cost of the implant and general staff. The septic implantation part was on average $3,142.87 more expensive than septic explantations (p <.001). CONCLUSIONS: Our study for the first time provides a detailed analysis of the major direct case costs of aseptic and septic revision TKA from the hospital-department's perspective which is the basis for long-term orientated decision making. In the future, our cost analysis has to be interpreted in relation to reimbursement estimates. This is important to check whether revision TKA lead to a financial loss for the operating department.

Does antibiotic resistance impair plasma susceptibility of multi-drug resistant clinical isolates of enterococci in vitro?

BACKGROUND: Cold atmospheric plasma could constitute an alternative against multi-drug resistant pathogens. Susceptibility of enterococci to cold atmospheric plasma was investigated in vitro. METHODS: 39 clinical isolates of enterococci were grouped dependent on the most important resistance patterns and treated on agar using dielectric barrier discharge plasma. These included enterococci with combined vancomycin- and high-level gentamicin resistance, high-level resistance to gentamicin (HLGR) only, vancomycin resistance alone (VRE), and enterococci susceptible to both. Susceptibility to cold atmospheric plasma was evaluated based on the zones of inhibition and examined in terms of the enterococcal group and the "degree" of drug resistance. RESULTS: Cold atmospheric plasma treatment killed all groups. Comparison of VRE and HLGR strains with non-VRE and non-HLGR isolates concerning zones of inhibition revealed that enterococci with special resistance patterns (VRE and HLGR) showed significantly smaller zones of inhibition than the sensitive ones. The mean of all isolates, irrespective of belonging to groups, showed smaller zones of inhibition with increasing "degree" of drug resistance. CONCLUSIONS: Cold atmospheric plasma treatment killed all isolates of enterococci, but its efficacy depended on the "degree" of drug resistance and on membership in special resistance groups with particular clinical-outbreak importance. However, a possible role of the different genetic lineages, which might be prone to acquiring more or less resistance phenotypes, may also play a role in this context.

In vitro susceptibility of methicillin-resistant and methicillin-susceptible strains of Staphylococcus aureus to two different cold atmospheric plasma sources.

BACKGROUND: Staphylococcus aureus may be the most important wound pathogen and causative for most of surgical site infections. As many anti-staphylococcal drugs are useless because of resistance, novel antimicrobial strategies are strongly needed and may be provided by cold atmospheric plasma (CP), which is being currently investigated for antiseptic efficacy. METHODS: To test the antimicrobial properties of CP against Staphylococcus aureus, 168 methicillin-susceptible isolates (MSSA) and 50 methicillin-resistant isolates (MRSA) were treated with two technically different plasma sources [an atmospheric pressure plasma jet (APPJ) and a dielectric barrier discharge plasma (DBD)] in vitro. RESULTS: CP treatment allowed a reproducible and significant growth reduction of MRSA and MSSA. However, MRSA was significantly less susceptible to treatment with DBD than was MSSA, while no difference between MRSA and MSSA was found using APPJ. CONCLUSIONS: As the initial physical antiseptic on skin, CP may be suitable for rapid decolonization of microbial pathogens in vivo. Each device must undergo validated efficacy testing prior to clinical application, as device related differences may occur.