Source strengths obtained with three clean air suits fulfilling the requirements for high performance in EN 13795-2:2019: An experimental study

Introduction: Clothing made from tight material worn by operating room staff adds to the effect achieved by ventilation in the effort to keep a low level of bacteria in the operating room air. The material used for clean air suits should be tested according to the standard EN 13795-2. Aim: The aim of the study was to investigate whether there was a difference in protective capacity between three clean air suits made from materials fulfilling the requirements of EN 13795-2:2019 and designed as described in Annex E of the standard. Materials and methods: Eight people (five men and three women) performed standardized movements in a dispersal chamber with a fixed supply air flow. Each person performed two test cycles with each clean air suit. Counts of colony-forming units (CFU) in the air were measured during testing and source strength was calculated for each test cycle. Results: The mean values of source strength for the three clean air suits were 1.4 CFU/s, 0.8 CFU/s and 0.7 CFU/s. The difference between the most and the least protective garment was statistically significant (p < 0.05). Conclusions: Clean air suits made from material fulfilling the requirements for ‘high performance’ in the standard EN 13795-2:2019 might show a significant difference in protective capacity when comparing source strength. Tests for measuring of source strength in a dispersal chamber can be performed as suggested in Annex E of the standard, i.e. ‘The test person is male, 20–50 years old, with no visible skin disorder’

Mediastinitis after Cardiac Surgery: Improvement of Bacteriological Diagnosis by Use of Multiple Tissue Samples and Strain Typing

The diagnosis of postsurgical mediastinitis (PSM) among patients with sternal wound complication (SWC) after cardiac surgery is sometimes difficult, as fever, elevated C-reactive protein levels, and chest pain can be caused by a general inflammatory reaction to the operative trauma and/or sternal dehiscence without infection. The definitions of PSM usually used emphasize clinical signs and symptoms easily observed by the surgeon. The aim of the study was to investigate whether the use of standardized multiple tissue sampling, optimal culturing methods, and strain typing, together with a microbiological criterion for infection, could identify more infected patients than clinical assessment alone. Patients reexplored due to SWC after cardiac artery bypass grafting (CABG) or heart valve replacement (HVR) with or without CABG performed at the Department for Cardio-Thoracic Surgery at the Uppsala University Hospital between 10 March 1998 and 9 September 2000 were investigated prospectively. Tissue samples were taken from the sternum or adjacent mediastinal tissue, preferably before the administration of antibiotics. Culturing was performed both directly (on agar plates) and using enrichment broth. Species identification was performed by standard methods, and strain typing was performed by pulsed-field gel electrophoresis. A total of 41 cases with at least five tissue samples each were included in the study group. Of these patients, 32 were infected according to the microbiological criterion (i.e., the same strain was found in ≥50% of the samples). Staphylococcus epidermidis was the primary pathogen in 38% of the cases (12/32), S. aureus was the primary pathogen in 31% (10/32), P. acnes was the primary pathogen in 25% (8/32), and S. simulans and S. haemolyticus were the primary pathogens in 3% (1/32) each. All cases of S. aureus infection and 86% (12/14) of coagulase-negative staphylococcus (CoNS) infections were identified from primary cultures. All cases fulfilling the microbiological criterion for S. aureus infection were clinically diagnosed as cases of infection, but among the 14 cases fulfilling the criterion for microbiological diagnosis of CoNS infection, only 10 appeared to qualify clinically as cases of infection. Among the patients with sternal dehiscence in whom a microbiological diagnosis was established, 67% (12/18) had a CoNS infection, compared to 14% (2/14) of those without sternal dehiscence. The difference was statistically significant. PSM caused by S. aureus is readily identified by the surgeon, whereas 30% of cases with CoNS infections may be misinterpreted as noninfected. Multiple sampling before administration of antibiotics, primary culturing on agar plates, species identification, strain typing, and susceptibility testing should be used to ensure a fast and microbiologically correct diagnosis which identifies the primary pathogen and infected patients among those with minor infective symptoms. The role of P. acnes as a possible cause of PSM needs further investigation. PSM caused by CoNS is significantly related to sternal dehiscence

Comparison of three distinct surgical clothing systems for protection from air-borne bacteria: A prospective observational study

Abstract Background To prevent surgical site infection it is desirable to keep bacterial counts low in the operating room air during orthopaedic surgery, especially prosthetic surgery. As the air-borne bacteria are mainly derived from the skin flora of the personnel present in the operating room a reduction could be achieved by using a clothing system for staff made from a material fulfilling the requirements in the standard EN 13795. The aim of this study was to compare the protective capacity between three clothing systems made of different materials – one mixed cotton/polyester and two polyesters - which all had passed the tests according to EN 13795. Methods Measuring of CFU/m3 air was performed during 21 orthopaedic procedures performed in four operating rooms with turbulent, mixing ventilation with air flows of 755 – 1,050 L/s. All staff in the operating room wore clothes made from the same material during each surgical procedure. Results The source strength (mean value of CFU emitted from one person per second) calculated for the three garments were 4.1, 2.4 and 0.6 respectively. In an operating room with an air flow of 755 L/s both clothing systems made of polyester reduced the amount of CFU/m3 significantly compared to the clothing system made from mixed material. In an operating room with air intake of 1,050 L/s a significant reduction was only achieved with the polyester that had the lowest source strength. Conclusions Polyester has a better protective capacity than cotton/polyester. There is need for more discriminating tests of the protective efficacy of textile materials intended to use for operating garment.</p

The impact of guidelines on sterility precautions during indwelling urethral catheterization at two acute-care hospitals in Sweden - a descriptive survey

Abstract Background To support a uniform and evidence-based practice for indwelling urinary catheterization in adults The European association of Urology Nurses (EAUN) published guidelines for this procedure in 2012. The Swedish national guidelines are based on the sterility precautions advocated by EAUN. Some hospitals have local guidelines with other requirements concerning sterility and leave to staff to decide how to perform the catheterization. The aim of this descriptive survey was to investigate the nurses´ self-reported sterility precautions during indwelling urethral catheterization at two acute-care hospitals, where the local guidelines differ in their sterility requirements. The study also aimed to analyze factors affecting conformity with sterility precautions in the EAUN-guidelines. Methods A structured questionnaire with questions concerning the participant, working conditions and performance of indwelling urethral catheterization was left to 931 nurses in two acute care hospitals. Chi-square test, Fisher’s exact test and Mann-Whitney U-test were used for descriptive statistics. Logistic regression was used to analyze variables associated with practicing the sterility precautions in the EAUN-guidelines. Results Answers were obtained from 852 persons (91.5%). Most of the participants called their insertion technique “non-sterile”. Regardless of designation of the technique the participants said that the indwelling urinary catheter (IUC) should be kept sterile during procedure. Despite that not everyone used sterile equipment to maintain sterility of the catheter. The nurses´ conformity with all the sterility precautions in the EAUN-guidelines were associated with working at departments for surgery and cardiology (OR 2.35, 95% CI 1.69–3.27), use of sterile set for catheterization (OR 2.06, 95% CI 1.42–2.97), use of sterile drapes for dressing on insertion area (OR 1.91, 95% CI 1.24–2.96) and using the term “sterile technique” for indwelling urethral catheterization (OR 1.64, 95% CI 1.11–2.43). Conclusions Only 55–74% of the nurses practiced one or more precautions that secured sterility of the IUC thus demonstrating a gap between the EAUN-guidelines and the actual performance. Adherence to the guidelines was associated with factors that facilitated an aseptic performance such as using a sterile set and sterile drapes. Healthcare-settings should ensure education and skill training including measures to ensure that the IUC is kept sterile during insertion