Surgical site infection after trochanteric and subtrochanteric fractures: a single centre retrospective analysis

Surgical site infection (SSI) following osteosynthesis of trochanteric or subtrochanteric fractures is a rare but serious complication with incidence rate ranging from 1 to 3%. SSIs are associated with higher mortality and increased length of hospital stay resulting in higher healthcare costs and loss of life quality. In this retrospective analysis all patients with SSI following osteosynthesis of trochanteric or subtrochanteric fractures at the Department of Trauma Surgery were identified. We included all surgical procedures performed from 1992 to 2018, using data from electronic health records and SSI-Trauma-Registry. The aim was to describe epidemiological data, as well as to identify parameters correlating with the occurrence of SSI and mortality. Of 2753 patients, 53 (1.9%) developed SSI. Longer operative time was demonstrated among patients with SSI (P = 0.008). Mortality during the first postoperative year was significantly higher in the SSI group (32.1% vs. 19.1%; P = 0.018), with detection of methicillin-sensitive (MSSA) and methicillin-resistant Staphylococcus aureus (MRSA; HR 4.13, CI 95% 1.24-13.80; P = 0.021) or Enterococcus spp. (HR 5.58, CI 95% 1.67-18.65; P = 0.005) being independent risk factors. Male sex (HR 2.25, 95% CI 1.86-2.73; P < 0.001) and higher mean age (HR 1.05, 95% CI 1.04-1.06; P < 0.001) were found to be predictors for 1-year mortality in non-infected patients. SSI rate was low with 1.9% and longer duration of surgery was associated with infection. Patients with SSI had a higher 1-year mortality, with detection of MSSA, MRSA and enterococci significantly increasing the risk of dying. Male sex and higher age were risk factors for one-year mortality in patients without SSI.

Revisiting the personal protective equipment components of transmission-based precautions for the prevention of COVID-19 and other respiratory virus infections in healthcare

The COVID-19 pandemic highlighted some potential limitations of transmission-based precautions. The distinction between transmission through large droplets vs aerosols, which have been fundamental concepts guiding infection control measures, has been questioned, leading to considerable variation in expert recommendations on transmission-based precautions for COVID-19. Furthermore, the application of elements of contact precautions, such as the use of gloves and gowns, is based on low-quality and inconclusive evidence and may have unintended consequences, such as increased incidence of healthcare-associated infections and spread of multidrug-resistant organisms. These observations indicate a need for high-quality studies to address the knowledge gaps and a need to revisit the theoretical background regarding various modes of transmission and the definitions of terms related to transmission. Further, we should examine the implications these definitions have on the following components of transmission-based precautions: (i) respiratory protection, (ii) use of gloves and gowns for the prevention of respiratory virus infections, (iii) aerosol-generating procedures and (iv) universal masking in healthcare settings as a control measure especially during seasonal epidemics. Such a review would ensure that transmission-based precautions are consistent and rationally based on available evidence, which would facilitate decision-making, guidance development and training, as well as their application in practice.

COVID-19 patient and personal safety - lessons learnt for pandemic preparedness and the way to the next normal

BACKGROUND

The COVID-19 pandemic has profoundly challenged societies and healthcare systems in particular. To prevent the spread of SARS-CoV-2, infection prevention and control (IPC) strategies had to be developed on the local, national and international level. The aim of this study is to provide details of the COVID-19 experience at the Vienna General Hospital (VGH) in the context of the national and international COVID-19 response for learning and improvement.

METHODS

This is a retrospective report, outlining the evolution of IPC measures and challenges encountered at the health facility (VGH), the national (Austria) and global level between February 2020 and October 2022.

RESULTS

The IPC strategy at the VGH has been continuously adapted to changes in the epidemiological setting, new legal directives and Austrian by-laws. The current strategy, nationally and internationally, focuses on endemicity rather than maximum transmission risk reduction. For the VGH, this has recently resulted in an increase in COVID-19 clusters. To protect our particularly vulnerable patients, many COVID-19 precautions have been maintained. Barriers to adequate IPC implementation at the VGH and other hospitals include a lack of sufficient isolation options and non-adherence with universal face mask regulations. Globally, misinformation on COVID-19 hampered an effective response.

CONCLUSIONS

This retrospective analysis of the COVID-19 response at the VGH and international reports underline the need for pandemic preparedness, readiness and response by improving future hospital design and infrastructure, conducting regular trainings for protective attire and increasing health literacy as now recently published in a concise document by WHO.

EPI-Net One Health reporting guideline for antimicrobial consumption and resistance surveillance data: a Delphi approach

Strategic and standardised approaches to analysis and reporting of surveillance data are essential to inform antimicrobial resistance (AMR) mitigation measures, including antibiotic policies. Targeted guidance on linking full-scale AMR and antimicrobial consumption (AMC)/antimicrobial residues (AR) surveillance data from the human, animal, and environmental sectors is currently needed. This paper describes the initiative whereby a multidisciplinary panel of experts (56 from 20 countries-52 high income, 4 upper middle or lower income), representing all three sectors, elaborated proposals for structuring and reporting full-scale AMR and AMC/AR surveillance data across the three sectors. An evidence-supported, modified Delphi approach was adopted to reach consensus among the experts for dissemination frequency, language, and overall structure of reporting; core elements and metrics for AMC/AR data; core elements and metrics for AMR data. The recommendations can support multisectoral national and regional plans on antimicrobials policy to reduce resistance rates applying a One Health approach.

ESCMID/EUCIC clinical practice guidelines on perioperative antibiotic prophylaxis in patients colonized by multidrug-resistant Gram-negative bacteria before surgery

SCOPE

The aim of the guidelines is to provide recommendations on perioperative antibiotic prophylaxis (PAP) in adult inpatients who are carriers of multidrug-resistant Gram-negative bacteria (MDR-GNB) before surgery.

METHODS

These evidence-based guidelines were developed after a systematic review of published studies on PAP targeting the following MDR-GNB: extended-spectrum cephalosporin-resistant Enterobacterales, carbapenem-resistant Enterobacterales (CRE), aminoglycoside-resistant Enterobacterales, fluoroquinolone-resistant Enterobacterales, cotrimoxazole-resistant Stenotrophomonas maltophilia, carbapenem-resistant Acinetobacter baumannii (CRAB), extremely drug-resistant Pseudomonas aeruginosa, colistin-resistant Gram-negative bacteria, and pan-drug-resistant Gram-negative bacteria. The critical outcomes were the occurrence of surgical site infections (SSIs) caused by any bacteria and/or by the colonizing MDR-GNB, and SSI-attributable mortality. Important outcomes included the occurrence of any type of postsurgical infectious complication, all-cause mortality, and adverse events of PAP, including development of resistance to targeted (culture-based) PAP after surgery and incidence of Clostridioides difficile infections. The last search of all databases was performed until April 30, 2022. The level of evidence and strength of each recommendation were defined according to the Grading of Recommendations Assessment, Development and Evaluation approach. Consensus of a multidisciplinary expert panel was reached for the final list of recommendations. Antimicrobial stewardship considerations were included in the recommendation development.

RECOMMENDATIONS

The guideline panel reviewed the evidence, per bacteria, of the risk of SSIs in patients colonized with MDR-GNB before surgery and critically appraised the existing studies. Significant knowledge gaps were identified, and most questions were addressed by observational studies. Moderate to high risk of bias was identified in the retrieved studies, and the majority of the recommendations were supported by low level of evidence. The panel conditionally recommends rectal screening and targeted PAP for fluoroquinolone-resistant Enterobacterales before transrectal ultrasound-guided prostate biopsy and for extended-spectrum cephalosporin-resistant Enterobacterales in patients undergoing colorectal surgery and solid organ transplantation. Screening for CRE and CRAB is suggested before transplant surgery after assessment of the local epidemiology. Careful consideration of the laboratory workload and involvement of antimicrobial stewardship teams before implementing the screening procedures or performing changes in PAP are warranted. High-quality prospective studies to assess the impact of PAP among CRE and CRAB carriers performing high-risk surgeries are advocated. Future well-designed clinical trials should assess the effectiveness of targeted PAP, including the monitoring of MDR-GNB colonization through postoperative cultures using European Committee on Antimicrobial Susceptibility Testing clinical breakpoints.

Infection prevention and control policies in hospitals and prevalence of highly resistant microorganisms: an international comparative study

BACKGROUND

There are differences in infection prevention and control (IPC) policies to prevent transmission of highly resistant microorganisms (HRMO). The aim of this study is to give an overview of the IPC policy of six European hospitals and their HRMO prevalence, to compare the IPC policies of these hospitals with international guidelines, and to investigate the hospitals' adherence to their own IPC policy.

METHODS

The participating hospitals were located in Salzburg (Austria), Vienna (Austria), Kayseri (Turkey), Piraeus (Greece), Rome (Italy) and Rotterdam (The Netherlands). Data were collected via an online survey. Questions were aimed at prevalence rates in the years 2014, 2015, 2016 of carbapenemase-producing Klebsiella pneumoniae (CPK), carbapenemase-producing Pseudomonas aeruginosa (CPPA), vancomycin-resistant Enterococcus faecium (VRE) and hospitals' IPC policies of 2017. Implemented IPC measures (i.e. with a self-reported adherence of > 90%) were counted (26 points maximal).

RESULTS

The self-reported prevalence of CPK per year was low in the Austrian and Dutch hospitals and high in the Turkish and Greek hospitals. CPPA was highly prevalent in the Turkish hospital only, while the prevalence of VRE in four hospitals, except the Austrian hospitals which reported lower prevalence numbers, was more evenly distributed. The Dutch hospital had implemented the most IPC measures (n = 21), the Turkish and Greek hospitals the least (n = 14 and 7, respectively).

CONCLUSION

Hospitals with the highest self-reported prevalence of CPK and CPPA reported the least implemented IPC measures. Also, hospitals with a higher prevalence often reported a lower adherence to own IPC policy.

Provision of safe patient care during the COVID-19 pandemic despite shared patient rooms in a tertiary hospital

Background

The COVID-19 pandemic has resulted in the disruption of healthcare systems. Vienna General Hospital (VGH), a tertiary hospital located in Austria, ran at almost full capacity despite high levels of community SARS-CoV-2 transmission and limited isolation room capacity. To ensure safe patient care, a bundle of infection prevention and control (IPC) measures including universal pre-admission screening and serial SARS-CoV-2 testing during hospitalization was implemented. We evaluated whether testing as part of our IPC approach was effective in preventing hospital outbreaks during different stages of the pandemic.

Methods

In this retrospective single center study, we analyzed the SARS-CoV-2 PCR test results of cases admitted to VGH between a low (15/05/2020–01/08/2020) and a high incidence period (15/09/2020–18/05/2021). Outcomes were the diagnostic yield of (a) admission screening, (b) the yield of serial testing during hospitalization and (c) the occurrence of healthcare-associated COVID-19 (HA-COVID-19) and SARS-CoV-2 related hospital outbreaks.

Results

The admission test positivity rate was 0.2% during the low and 2.3% during the high incidence phase. Regarding test conversions, 0.04% (low incidence phase) and 0.5% (high incidence phase) of initially negative cases converted to a positive test result within 7 days after admission The HA-COVID-19 incidence rate per 100,000 patient days was 1.0 (low incidence phase) and 10.7 (high incidence phase). One COVID-19 outbreak affecting eight patients in total could be potentially ascribed to the non-compliance with our IPC protocol.

Conclusion

Testing in conjunction with other IPC measures enabled the safe provision of patient care at a hospital with predominantly shared patient rooms despite high case numbers in the community.

Supplementary Information

The online version contains supplementary material available at 10.1186/s13756-022-01091-1.

ESCMID guidelines on testing for SARS-CoV-2 in asymptomatic individuals to prevent transmission in the healthcare setting

Scope

This guideline addresses the indications for direct testing of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in asymptomatic individuals in health care facilities, with the aim to prevent SARS-CoV-2 transmissions in these settings. The benefit of testing asymptomatic individuals to create a safe environment for patients and health care workers must be weighed against potential unintended consequences, including delaying necessary treatments owing to false positive results and lower quality of care owing to strict isolation measures.

Methods

A total of nine PICOs (population, intervention, comparison, outcome) on the topic of testing asymptomatic individuals was selected by the panel members. Subsequently, a literature search for existing guidelines and systematic reviews was performed on PubMed, Epistemonikos, and RecMap using relevant filters available in each database. Data on article/recommendation type, setting, target population, intervention, and quality of the evidence were extracted. Credibility of the systematic reviews was evaluated using the AMSTAR tool, and level of agreement with available recommendation was evaluated with the AGREE II score. Because the evidence available from systematic reviews was deemed insufficiently updated to formulate relevant recommendations, an additional search targeting relevant guidance documents from major public health institutions and original studies was performed. Provisional recommendations were discussed via web conferences until agreement was reached, and final recommendations were formulated according to the GRADE approach.

Recommendations

Recommendations were formulated regarding systematic testing in asymptomatic individuals upon admission to a health care setting, during hospital stay, before elective procedures, and before scheduled nonsurgical procedures. Moreover, recommendations regarding testing of asymptomatic visitors, personal caregivers, and health care workers in health care facilities were presented. Recommendations also were given on contact tracing in asymptomatic patients or health care workers and the possibility of a negative screening test to shorten the quarantine period. Furthermore, if applicable, recommendations were specified to transmission rate and vaccination coverage.

The effectiveness of surface disinfectants and a micellic H2O2 based water disinfectant on Candida auris

BACKGROUND

As infection control faces new challenges from emerging, multidrug resistant strains of the yeast Candida auris, this study was conducted in order to examine the efficacy of hospital surface disinfectants and a new water disinfectant against C. auris biofilm forms.

METHODS

We tested four reference strains of C. auris (NCPF8971, NCPF8977, NCPF8984, DSM21092) and one C. albicans strain (ATCC10231) against disinfectants based on ethanol (ETH), quaternary ammonium (QAC), a combination of glutaraldehyde, quaternary ammonium and surfactant (ALD) and potassium peroxymonosulfate (PP) as well as 3.4% H₂O₂ and 4.25% H₂O₂ alone. In addition, a micellic-based formulation containing 17% v/v hydrogene peroxide disinfectant (mH₂O₂) was tested. The efficacy of the disinfectants was measured in a 96-well plate using tetrazolium salt reduction (XTT) and the log₁₀ reduction assay.

RESULTS

ETH and QAC displayed in clinically recommended concentrations more than 5log₁₀ reduction and more than 80% XTT activity reduction for all of the Candida biofilms and planktonic cells. Only biofilms of C. auris NCPF8984 were additionally sensitive to all remaining disinfectants. All tested C. auris biofilms were sensitive to PP disinfectant and showed more than 5log₁₀ reduction. However, the XTT assay showed a reduction of less than 80% for the PP disinfectant, indicating the presence of active but non-culturable cells. The 25% mH₂O₂ (corresponding to 4.25% H₂O₂) killed Candida biofilms after 1 minute.

Governance aspects of large-scale implementation of automated surveillance of healthcare-associated infections

OBJECTIVES

Surveillance of healthcare-associated infections (HAI) is increasingly automated by applying algorithms to routine-care data stored in electronic health records. Hitherto, initiatives have mainly been confined to single healthcare facilities and research settings, leading to heterogeneity in design. The PRAISE network - Providing a Roadmap for Automated Infection Surveillance in Europe - designed a roadmap to provide guidance on how to move automated surveillance (AS) from the research setting to large-scale implementation. Supplementary to this roadmap, we here discuss the governance aspects of automated HAI surveillance within networks, aiming to support both the coordinating centres and participating healthcare facilities as they set up governance structures and to enhance involvement of legal specialists.

METHODS

This article is based on PRAISE network discussions during two workshops. A taskforce was installed that further elaborated governance aspects for AS networks by reviewing documents and websites, consulting experts and organizing teleconferences. Finally, the article has been reviewed by an independent panel of international experts.

RESULTS

Strict governance is indispensable in surveillance networks, especially when manual decisions are replaced by algorithms and electronically stored routine-care data are reused for the purpose of surveillance. For endorsement of AS networks, governance aspects specifically related to AS networks need to be addressed. Key considerations include enabling participation and inclusion, trust in the collection, use and quality of data (including data protection), accountability and transparency.

CONCLUSIONS

This article on governance aspects can be used by coordinating centres and healthcare facilities participating in an AS network as a starting point to set up governance structures. Involvement of main stakeholders and legal specialists early in the development of an AS network is important for endorsement, inclusivity and compliance with the laws and regulations that apply.

PRAISE: providing a roadmap for automated infection surveillance in Europe

INTRODUCTION

Healthcare-associated infections (HAI) are among the most common adverse events of medical care. Surveillance of HAI is a key component of successful infection prevention programmes. Conventional surveillance - manual chart review - is resource intensive and limited by concerns regarding interrater reliability. This has led to the development and use of automated surveillance (AS). Many AS systems are the product of in-house development efforts and heterogeneous in their design and methods. With this roadmap, the PRAISE network aims to provide guidance on how to move AS from the research setting to large-scale implementation, and how to ensure the delivery of surveillance data that are uniform and useful for improvement of quality of care.

METHODS

The PRAISE network brings together 30 experts from ten European countries. This roadmap is based on the outcome of two workshops, teleconference meetings and review by an independent panel of international experts.

RESULTS

This roadmap focuses on the surveillance of HAI within networks of healthcare facilities for the purpose of comparison, prevention and quality improvement initiatives. The roadmap does the following: discusses the selection of surveillance targets, different organizational and methodologic approaches and their advantages, disadvantages and risks; defines key performance requirements of AS systems and suggestions for their design; provides guidance on successful implementation and maintenance; and discusses areas of future research and training requirements for the infection prevention and related disciplines. The roadmap is supported by accompanying documents regarding the governance and information technology aspects of implementing AS.

CONCLUSIONS

Large-scale implementation of AS requires guidance and coordination within and across surveillance networks. Transitions to large-scale AS entail redevelopment of surveillance methods and their interpretation, intensive dialogue with stakeholders and the investment of considerable resources. This roadmap can be used to guide future steps towards implementation, including designing solutions for AS and practical guidance checklists.

White Paper: Bridging the gap between human and animal surveillance data, antibiotic policy and stewardship in the hospital sector-practical guidance from the JPIAMR ARCH and COMBACTE-MAGNET EPI-Net networks

BACKGROUND

Antimicrobial surveillance and antimicrobial stewardship (AMS) are essential pillars in the fight against antimicrobial resistance (AMR), but practical guidance on how surveillance data should be linked to AMS activities is lacking. This issue is particularly complex in the hospital setting due to structural heterogeneity of hospital facilities and services. The JPIAMR ARCH and COMBACTE-MAGNET EPI-Net networks have joined efforts to formulate a set of target actions for linking surveillance data with AMS activities.

METHODS

A scoping review of the literature was carried out addressing research questions on three areas: (i) AMS leadership and accountability; (ii) antimicrobial usage and AMS; (iii) AMR and AMS. Consensus on the target actions was reached through a RAND-modified Delphi process involving over 40 experts in different fields from 18 countries.

RESULTS

Evidence was retrieved from 51 documents. Initially 38 targets were proposed, differentiated as essential or desirable according to clinical relevance, feasibility and applicability to settings and resources. In the first consultation round, preliminary agreement was reached for 32 targets. Following a second consultation, 27 targets were approved, 11 were deleted and 4 were suggested for rephrasing, leading to a final approved list of 34 target actions in the form of a practical checklist.

CONCLUSIONS

This White Paper provides a pragmatic and flexible tool to guide the development of calibrated hospital-surveillance-based AMS interventions. The strength of this tool is that it is a comprehensive perspective that takes into account the hospital patient case-mix and the related epidemiology, which ultimately drives antimicrobial usage, and the feasibility in low-resource settings.

Ultraviolet disinfection robots to improve hospital cleaning: Real promise or just a gimmick?

The global COVID-19 pandemic due to the novel coronavirus SARS-CoV-2 has challenged the availability of traditional surface disinfectants. It has also stimulated the production of ultraviolet-disinfection robots by companies and institutions. These robots are increasingly advocated as a simple solution for the immediate disinfection of rooms and spaces of all surfaces in one process and as such they seem attractive to hospital management, also because of automation and apparent cost savings by reducing cleaning staff. Yet, there true potential in the hospital setting needs to be carefully evaluated. Presently, disinfection robots do not replace routine (manual) cleaning but may complement it. Further design adjustments of hospitals and devices are needed to overcome the issue of shadowing and free the movement of robots in the hospital environment. They might in the future provide validated, reproducible and documented disinfection processes. Further technical developments and clinical trials in a variety of hospitals are warranted to overcome the current limitations and to find ways to integrate this novel technology in to the hospitals of to-day and the future.

Disinfection of contaminated metal implants with an Er:YAG laser

Infections related to orthopedic procedures are considered particularly severe when implantation materials are used, because effective treatments for biofilm removal are lacking. In this study, the relatively new approach for infection control by using an erbium:yttrium-aluminum-garnet (Er:YAG) laser was tested. This laser vaporizes all water containing cells in a very effective, precise, and predictable manner and results in only minimal thermal damage. For preliminary testing, 42 steel plates and 42 pins were seeded with mixed cultures. First, the minimally necessary laser energy for biofilm removal was determined. Subsequently, the effectiveness of biofilm removal with the Er:YAG laser and the cleansing of the metal implants with octenidine-soaked gauze was compared. Then, we compared the effectiveness of biofilm removal on 207 steel pins from 41 patients directly after explantation. Sonication and scanning electron microscopy were used for analysis. Laser fluences exceeding 2.8  J/cm² caused a complete extinction of all living cells by a single-laser impulse. Cleansing with octenidine-soaked gauze and irradiation with the Er:YAG laser are both thoroughly effective when applied to seeded pins. In contrast, when explanted pins with fully developed biofilms were analyzed, we found a significant advantage of the laser procedure. The Er:YAG laser offers a secure, complete, and nontoxic eradication of all kinds of pathogens from metal implants without damaging the implant and without the possible development of resistance. The precise noncontact removal of adjacent tissue is a decisive advantage over conventional disinfectants. Therefore, laser irradiation could become a valuable method in every debridement, antibiotics, and implant retention procedure.

A novel micellar formulation based on natural plant extracts enhances the efficacy of hydrogen peroxide against biofilms of Staphylococcus spp. and Pseudomonas aeruginosa

The antibacterial efficacy of hydrogen peroxide encapsulated in micelles (mH₂O₂) against biofilms was compared with that of hydrogen peroxide alone and of three commercially available aqueous biocides. The activity of mH₂O₂ on 24-h biofilms of reference strains of Staphylococcus spp. and Pseudomonas aeruginosa was tested in a static microtiter plate model. The biofilms were incubated with mH₂O₂ (17% v/v H₂O₂, 2% lactic acid, 0.3% phytoextract, H₂O) and its individual ingredients and compared with three aqueous biocides at different concentrations and times of exposure. After 5-min exposure, 10% mH₂O₂ (corresponding to 1.7% v/v H₂O₂) achieved > 8 log₁₀ reductions against all the test strains, while 1.7% H₂O₂ achieved a maximum of 1.5 log₁₀ reduction. After 5-min exposure, none of the commercially available biocides tested showed themselves to be capable of completely eliminating the test strains embedded in biofilms. Hydrogen peroxide encapsulated in micelles demonstrated enhanced activity against planktonic cells and biofilms of Staphylococcus spp. and P. aeruginosa.

Infection control and risk factors for acquisition of carbapenemase-producing enterobacteriaceae. A 5 year (2011-2016) case-control study

Background

Carbapenemase-producing enterobacteriaceae (CPE) are a major threat for severely ill patients. However, only limited data on the epidemiology and on evidence-based infection prevention and control measures are available. The aim of this study was to investigate the epidemiology of patients with CPE, characterizing the CPE isolates by their resistance mechanisms and genetic similarity, to explore risk factors for their acquisition, and to evaluate the effectiveness of the current CPE infection control measures.

Methods

A retrospective case-control study was performed using data from 2011 to 2016 in a 1800-bed academic hospital in Central Europe, where risk-based screening at patients´ admission is performed. Carbapenem resistance mechanisms of all carbapenem resistant enterobacteriaceae from patients admitted during this period were investigated. Clinical data of the CPE-positive patients were analysed and compared to a matched control group (case-control ratio of 1:3). We performed univariate and multivariate statistical analysis to identify risk factors for CPE acquisition.

Results

Of 621,623 admitted patients in the study period, 75 patients with carriage of carbapenem resistant enterobacteriaceae were included (0.12/1000 admittances). Carbapenemase-encoding genes were detected in 77.3% (58/75) of patients with carbapenem-resistant enterobacteriaceae. The enzyme blaOXA-48 was found in 34.5% (20/58), blaKPC in 29.3% (17/58), blaNDM enzymes in 20.7% (12/58) and blaVIM in 8.6% (5/58) of the isolates. The overall mortality among CPE patients was 25.9% (15/58) and attributable mortality of CPE was 53.3% (8/15). Multivariate analysis revealed four risk factors to be independent predictors of CPE carriage: the length of hospital admission > 20 days (AOR: 4.9, 95% CI: 1.4–15.5; P <  0.001), hospital admission within the previous year (AOR: 22.3, 95% CI: 3.9–88.4; P <  0.001), exposure to a healthcare facility in a country with high or unknown carbapenem-resistant enterobacteriaceae prevalence 3 months before admission (AOR: 11.8, 95% CI: 2.2–63.2; P <  0.01) and the use of antibiotics longer than 10 days (AOR: 5.2, 95% CI: 1.4–35.9; P <  0.05). The current risk-based screening strategy at hospital admission could not identify 37 (63.8%) of the 58 CPE-positive patients. Epidemiological investigation and genotyping revealed that no outbreaks due to CPE occurred during this period.

Conclusion

Overall, the CPE carriage rate in patients was very low, the attributable mortality, however, is alarming (53%). BlaOXA-48 and blaKPC were the main cause of carbapenem resistance in enterobacteriaceae. Although the strict application of standard infection control measures was effective for prevention of outbreaks in this setting, an enlarged risk based targeted screening strategy has to be implemented.

Various biofilm matrices of the emerging pathogen Staphylococcus lugdunensis: exopolysaccharides, proteins, eDNA and their correlation with biofilm mass

Staphylococcus lugdunensis is an emerging high-virulent pathogen causative of hospital-acquired infections. Biofilm formation is a complex pathogenic process that leads to well-established bacterial communities. There is a paucity of data on the composition of the biofilm matrix among S. lugdunensis strains. Here, twenty-two S. lugdunensis clinical isolates, mainly from orthopaedic infections but also from other clinical sources, were sub-grouped by ribotyping and dendrogram analysis. Biofilms were analysed by fluorimetric methods based on FITC-Wheat Germ Agglutinin, SYPRO Ruby and TOTO-1 dyes to detect exopolysaccharides, proteins and extracellular DNA (eDNA), respectively. Biofilm morphology was investigated under confocal laser scanning microscopy (CLSM). Isolates displayed intriguing diversities in biofilm mass and matrix composition. The content of exopolysaccharides was found to be to be strongly associated with the biofilm mass (R² = 0.882), while the content of proteins turned out to be weakly (R² = 0.465) and that of eDNA very weakly associated (R² = 0.202) to the biofilm mass.

Bayesian inversion for a biofilm model including quorum sensing

We propose a mathematical model based on a system of partial differential equations (PDEs) for biofilms. This model describes the time evolution of growth and degradation of biofilms which depend on environmental factors. The proposed model also includes quorum sensing (QS) and describes the cooperation among bacteria when they need to resist against external factors such as antibiotics. The applications include biofilms on teeth and medical implants, in drinking water, cooling water towers, food processing, oil recovery, paper manufacturing, and on ship hulls. We state existence and uniqueness of solutions of the proposed model and implement the mathematical model to discuss numerical simulations of biofilm growth and cooperation. We also determine the unknown parameters of the presented biofilm model by solving the corresponding inverse problem. To this end, we propose Bayesian inversion techniques and the delayed-rejection adaptive-Metropolis (DRAM) algorithm for the simultaneous extraction of multiple parameters from the measurements. These quantities cannot be determined directly from the experiments or from the computational model. Furthermore, we evaluate the presented model by comparing the simulations using the estimated parameter values with the measurement data. The results illustrate a very good agreement between the simulations and the measurements.

Prevalence and incidence of surgical site infections in the European Union/European Economic Area: how do these measures relate?

BACKGROUND

In 2011-2012, the European Centre for Disease Prevention and Control (ECDC) initiated the first European point prevalence survey (PPS) of healthcare-associated infections (HCAIs) in addition to targeted surveillance of the incidence of specific types of HCAI such as surgical site infections (SSIs).

AIM

To investigate whether national and multi-country SSI incidence can be estimated from ECDC PPS data.

METHODS

In all, 159 hospitals were included from 15 countries that participated in both ECDC surveillance modules, aligning surgical procedures in the incidence surveillance to corresponding specialties from the PPS. National daily prevalence of SSIs was simulated from the incidence surveillance data, the Rhame and Sudderth (R&S) formula was used to estimate national and multi-country SSI incidence from the PPS data, and national incidence per specialty was predicted using a linear model including data from the PPS.

FINDINGS

The simulation of daily SSI prevalence from incidence surveillance of SSIs showed that prevalence fluctuated randomly depending on the day of measurement. The correlation between the national aggregated incidence estimated with R&S formula and observed SSI incidence was low (correlation coefficient = 0.24), but specialty-specific incidence results were more reliable, especially when the number of included patients was large (correlation coefficients ranging from 0.40 to 1.00). The linear prediction model including PPS data had low proportion of explained variance (0.40).

CONCLUSION

Due to a lack of accuracy, use of PPS data to estimate SSI incidence is recommended only in situations where incidence surveillance of SSIs is not performed, and where sufficiently large samples of PPS data are available.

Analysis of the challenges in implementing guidelines to prevent the spread of multidrug-resistant gram-negatives in Europe

OBJECTIVE

The main objective of the study was to investigate major differences among European countries in implementing infection prevention and control (IPC) measures and reasons for reduced compliance.

DESIGN

An online survey including experts in IPC and a gap analysis were conducted to identify major limitations in implementing IPC guidelines.

SETTING

Europe.

MAIN OUTCOME MEASURES

Four areas were targeted: (1) healthcare structure, (2) finances, (3) culture and (4) education and awareness. Perceived compliance to IPC measures was classified as low (<50%), medium (50% to 80%) and high (>80%). Countries were classified in three regions: North-Western Europe (NWE), Eastern Europe (EE) and Southern Europe (SE).

RESULTS

In total, 482 respondents from 34 out of 44 (77.3%) European countries participated. Respondents reported availability of national guidelines to control multidrug-resistant Gram-negatives (MDR-GN) in 20 countries (58.0%). According to participants, compliance with IPC measures ranged from 17.8% (screening at discharge) to 96.0% (contact precautions). Overall, three areas were identified as critical for the compliance rate: (1) number of infection control staff, (2) IPC dedicated educational programmes and (3) number of clinical staff. Analysis of reasons for low compliance showed high heterogeneity among countries: participants from NWE and SE deemed the lack of educational programmes as the most important, while those from EE considered structural reasons, such as insufficient single bed rooms or lacking materials for isolation, as main contributors to the low compliance.

CONCLUSIONS

Although national guidelines to reduce the spread of MDR-GN are reported in the majority of the European countries, low compliance with IPC measures was commonly reported. Reasons for the low compliance are multifactorial and vary from region to region. Cross-country actions to reduce the spread of MDR-GN have to consider structural and cultural differences in countries. Locally calibrated interventions may be fruitful in the future.

Clinical characteristics of a large cohort of patients with positive culture of Fusobacterium necrophorum

Background: Fusobacterium necrophorum is a rare pathogen, mostly affecting young adults, causing infections of the head and neck, typically described as the Lemierre's syndrome. Today this symptom complex has become increasingly rare and has almost turned to a 'forgotten disease'. Methods: We performed a retrospective, descriptive study to identify the clinical features of patients with positive culture of F. necrophorum. Additionally, the antibiotic susceptibility profile of the pathogens was analysed. Results: During a period of 22 years 36 patients with at least one isolate of F. necrophorum were identified. Mostly tonsillar and peritonsillar abscesses were found, 10 patients were identified with bacteraemia, but only 4 patients presented with symptoms like sore throat, fever and swollen cervical lymph nodes, which may suggest Lemierre's. Most of the isolates (33/35) showed sensitivity to all tested antibiotics. Conclusion: Appropriate techniques are needed to detect F. necropho rum, especially from throat swabs, in the microbiological laboratory. Current clinical and microbiological practice may lead to under-diagnosis of infections caused by F. necrophorum. Further research is needed to define the colonization rate and to optimize methods for detection as well as identification of virulence.

Epidemiology of Urinary Tract Infections in HIV Positive Patients at a Tertiary Care University Hospital in Central Europe (2011 - 2016)

OBJECTIVES

There is limited published data concerning the recent epidemiology of urinary tract infections (UTI) in HIV-patients, thus we analysed independent risk factors for UTI in HIV positive individuals and antimicrobial resistance rates of E. coli to antimicrobial agents commonly used in UTI. To determine the prevalence of symptomatic urinary tract infections (UTI) in HIV-patients, we performed a retrospective case-control study.

METHODS

We included 313 HIV-patients, 101 with UTI and 212 age and gendermatched controls, attending the HIV outpatient clinic at the Vienna University Hospital (VUH) over a period from January 2011 to September 2016. The patients' specific data was gathered from the electronic database of the VUH. The statistical analysis was performed using SPSS Software Version 20.0.

RESULTS

HIV infected individuals with CD4 count >200 cells/mm3 were less likely than HIV infected individuals with CD4 count <200 cells/mm3 to experience UTI (OR 0.811, 95% CI 0.712-0.923 vs. OR 2.555, 95% CI 1.553 - 4.205, respectively). The in vitro resistance rate of E. coli to antimicrobial agents was as follows: ciprofloxacin (41%), mecillinam (20.5%), trimethoprim (61%), ampicillin (67%), ampicillin/ clavulanic acid (23%), cefuroxime (17%), nitrofurantoin (2%), amikacin (0%) and gentamicin (9.5%).

CONCLUSION

Immunological status (CD4 count) is an important parameter for risk assessment of UTIs in HIV-patients. The increased resistance rate of E. coli to commonly used antimicrobial agents needs to be considered when it comes to the management of UTI, additionally, surveillance strategies should be implemented in HIV-patients.

Specific Virology: Viruses as Diseases

1796: Jenner transfers cowpox material from a milkmaid to a boy and shows evidence of immunity generated by re-vaccination with virulent pox material.

Impact of participation in a surgical site infection surveillance network: results from a large international cohort study

BACKGROUND

Surveillance of surgical site infections (SSIs) is a core component of effective infection control practices, though its impact has not been quantified on a large scale.

AIM

To determine the time-trend of SSI rates in surveillance networks.

METHODS

SSI surveillance networks provided procedure-specific data on numbers of SSIs and operations, stratified by hospitals' year of participation in the surveillance, to capture length of participation as an exposure. Pooled and procedure-specific random-effects Poisson regression was performed to obtain yearly rate ratios (RRs) with 95% confidence intervals (CIs), and including surveillance network as random intercept.

FINDINGS

Of 36 invited networks, 17 networks from 15 high-income countries across Asia, Australia and Europe participated in the study. Aggregated data on 17 surgical procedures (cardiovascular, digestive, gynaecological-obstetrical, neurosurgical, and orthopaedic) were collected, resulting in data concerning 5,831,737 operations and 113,166 SSIs. There was a significant decrease in overall SSI rates over surveillance time, resulting in a 35% reduction at the ninth (final) included year of surveillance (RR: 0.65; 95% CI: 0.63-0.67). There were large variations across procedure-specific trends, but strong consistent decreases were observed for colorectal surgery, herniorrhaphy, caesarean section, hip prosthesis, and knee prosthesis.

CONCLUSION

In this large, international cohort study, pooled SSI rates were associated with a stable and sustainable decrease after joining an SSI surveillance network; a causal relationship is possible, although unproven. There was heterogeneity in procedure-specific trends. These findings support the pivotal role of surveillance in reducing infection rates and call for widespread implementation of hospital-based SSI surveillance in high-income countries.

Chlorhexidine-coated surgical gloves influence the bacterial flora of hands over a period of 3 hours

Background

The risk of SSI increases in the presence of foreign materials and may be caused by organisms with low pathogenicity, such as skin flora derived from hands of surgical team members in the event of a glove breach. Previously, we were able to demonstrate that a novel antimicrobial surgical glove coated chlorhexidine-digluconate as the active ingredient on its inner surface was able to suppress surgeons' hand flora during operative procedures by a magnitude of 1.7 log₁₀ cfu/mL. Because of the clinical design of that study, we were not able to measure the full magnitude of the possible antibacterial suppression effect of antimicrobial gloves over a full 3 h period.

Methods

The experimental procedure followed the method for assessment of the 3-h effects of a surgical hand rub's efficacy to reduce the release of hand flora as described in the European Norm EN 12791. Healthy volunteers tested either an antimicrobial surgical glove or non-antimicrobial surgical latex gloves in a standardized laboratory-based experiment over a wear time of 3 h.

Results

Wearing antimicrobial surgical glove after a surgical hand rub with 60% (v/v) n-propanol resulted in the highest 3-h reduction factor of 2.67 log₁₀. Non-antimicrobial surgical gloves demonstrated significantly lower (p ≤ 0.01) 3-h reduction factors at 1.96 log₁₀ and 1.68 log₁₀, respectively. Antibacterial surgical gloves are able to maintain a sustainable bacterial reduction on finger tips in a magnitude of almost 3 log₁₀ (log₁₀ 2.67 cfu) over 3 h wear time.

Conclusion

It was demonstrated that wear of an antibacterial surgical glove coated with chlorhexidine-digluconate is able to suppress resident hand flora significantly over a period of 3-h.

A survey on current knowledge, practice and beliefs related to preoperative antimicrobial decolonization regimens for prevention of surgical site infections among Austrian surgeons

BACKGROUND

Various measures are considered to reduce the risk of surgical site infection (SSI), including preoperative decolonization. Details of preoperative decolonization practices in surgical departments have not been investigated in Austria.

AIM

To analyse the current situation of pre-surgical patient decolonization in national hospitals and to assess the current knowledge on this procedure among surgeons of different surgical disciplines.

METHODS

A 12-point structured questionnaire was distributed to all Austrian hospitals with at least one surgical department.

FINDINGS

Two-thirds (103/158; 65%) of responding surgeons stated that any type of preoperative decolonization is implemented in their surgical department. There was heterogeneity of different protocols, ranging from decolonization of only known S. aureus carriers, of a subgroup of patients, or universal decolonization of all patients before elective surgery. Octenidine was the most frequently used antimicrobial compound (60.2%), followed by mupirocin (38.8%), triclosan (14.6%), polyhexanide (12.6%), chlorhexidine (11.7%), and didecyldimonium chloride (7.8%).

CONCLUSION

Preoperative decolonization seems to be performed in Austrian hospitals on a routine basis. However, this measure is implemented using a variety of modalities, antimicrobial compounds, and staff. Since our survey also demonstrated that those who are better informed about preoperative decolonization are also those who are more convinced of the usefulness of the preventive measure, future activities should not only focus on generating more comparable studies in this field, but should also include targeted education.

Incidence of risk factors for bloodstream infections in patients with major burns receiving intensive care: A retrospective single-center cohort study

OBJECTIVES

The objective was primarily to identify risk factors for bloodstream infections (BSI) caused by different pathogens.

METHODS

A retrospective single-center cohort study was performed on 472 burn patients with an abbreviated burn severity index (ABSI)≥3, a total burn surface area (TBSA)≥10%, and an ICU stay of at least 24h. Risk factors for different BSI pathogens were analyzed by competing risks regression model of Fine and Gray.

RESULTS

A total of 114 burn patients developed 171 episodes of BSIs caused by gram-negative bacteria (n=78;46%), gram-positive bacteria (n=69;40%), and fungi (n=24;14%) median after 14days (range, 1-164), 16days (range, 1-170), and 16days (range, 0-89), respectively. A total of 24/114 patients (21%) had fatal outcomes. Isolation of the most common bloodstream isolates Enterococcus sp. (n=26), followed by Candida sp. and Pseudomonas sp. (n=22 for both) was significantly associated with increased TBSA (p≤0.006) and ABSI (p<0.0001) and need for fasciotomy (p<0.01). The death risk of patients with MDR gram-negative bacteremia was significantly increased by a hazard ratio of 12.6 (95% CI:4.8-32.8; p<0.0001).

CONCLUSIONS

A greater TBSA and ABSI were associated with a significantly higher incidence of BSIs caused by Pseudomonas sp., Enterococcus sp. and Candida sp.

Time-Dependent Effects of Rifampicin on Staphylococcal Biofilms

Objective

To test the time-dependent effects of rifampicin on established biofilms of Staphylococcus epidermidis isolated from patients with cardiac implant infections and catheter-related bacteremia.

Methods

Biofilms were grown in microtiter plates for 24 hours, dyed and stained with crystal violet. The mean optical density (OD) was used for quantification. The OD ratio (ODr = OD of the treated biofilm/OD of the untreated biofilm) was used to measure changes in the thickness of the biofilms over the time. Biofilms were incubated with rifampicin (0.6 mg/mL) for 1, 5, 15, 30 and 60 minutes. Unstained biofilms were sonicated and plated on Columbia agar for time-kill curves.

Results

The incubation of the biofilms with rifampicin led to a significant reduction of the OD of the biofilms within 1 minute (ODr baseline: 1; ODr 1 min: 0.333 ± 0.131) (p<0.001). With regard to bacterial killing, rifampicin reduced the mean log count, but viable bacteria were still grown from biofilms in 13 out of 28 isolates despite MIC values < 0.01 mg/L.

Conclusions

In conclusion, our results confirm that rifampicin at a concentration of 1.2 mg/mL immediately reduces established biofilms formed by S. epidermidis although it is not bactericidal despite very low MICs at planktonic conditions.

Clinical Behavior of Implant Infections Due to Staphylococcus Epidermidis

Surgical implants and other foreign material are increasingly used in modern medicine to restore or to improve the function of the human body. Infection of an implant is associated with considerable morbidity due to frequent hospitalizations, surgery and antimicrobial treatment. The underlying mechanism is the formation of a bacterial biofilm on the surface of the implanted body. The recognition and diagnosis of implant infections is essential for further therapy and, above all, the decision to remove and exchange the implant.

Methods

We compared the data of 60 patients with implant infections with those of 60 patients with transient bacteremia caused by Staphylococcus epidermidis. The pathogens isolated from blood were characterized with regard to antimicrobial susceptibility and formation of biofilms using a static microtiter plate model. Wild type skin isolates from non-hospitalized healthy volunteers served as control with regard to antimicrobial susceptibility and biofilm formation.

Results

Clinical signs and symptoms, underlying diseases and outcome were not different in either group. However, patients with implant infection had fever over a longer time (mean 12 days versus 3 days, respectively, p & 0.05) and more often positive blood cultures than patients with transient bacteremia (3.1 versus 1.2, p & 0.05). Thrombocytopenia was observed in patients with implant infections but not in patients with transient bacteremia (p & 0.05). Biofilms were formed in 86.4 % of the isolates in implant infection, in 88.8 % in transient bacteremia and in 76.9 % of the isolates from healthy volunteers (not significant). Multi-resistance to penicillin, oxacillin, erythromycin, clindamycin, ciprofloxacin and trimethoprim was more common in the hospital strains than in the wild type strains (75.6 % versus 48.7 %, p & 0.05).

Conclusions

The clinical features of implant infections are indistinguishable from those of transient bacteremia. Persisting fever and multiple blood culture yielding the growth of skin flora bacteria are strong indicators for infection of implanted material. Biofilm formation and antimicrobial multiresistance, as common in implant infection as in transient bacteremia, seem to be accessory factors in infections due to Staphylococcus epidermidis.

Combating Implant Infections. Remarks by a Women's Team

Research on implant infections requires cooperative efforts and integration between basic and clinical expertises. An international group of women scientists is acting together in this field. The main research topics of the participants of this group are described. Formation of bacterial biofilms, antibiotic resistance and production of virulence factors like adhesins and toxins are investigated. New biomaterials, coatings and drugs designed to inhibit microbial adhesion are evaluated, and infection-resistant biomaterials are under study, such as a novel heparinizable polycarbonate-urethane (Bionate) or incorporation of diamino-diamide-diol (PIME) to reduce bacterial attachment. The correlation between biofilm production and the accessory-gene-regulator (agr) is investigated in Staphylococcus aureus. The ability to form biofilm has also been shown to be one of the important virulence factors of Enterococcus faecalis, favouring colonization of inert and biological surfaces. The study of quorum sensing has led to the discovery of a quorum sensing inhibitor termed RIP that suppresses staphylococcal biofilm and infections. The immune response and the local defence mechanisms of the host against implant-associated infections, activation and infiltration of immunocompetent cells into the sites of infection have been studied in patients with implant-associated osteomyelitis. Production of monoclonal antibodies (mAbs) as possible vaccines against the staphylococcal collagen-binding MSCRAMMs is in progress. (Int J Artif Organs 2008; 31: 858–64)

Effects of Tigecycline, Linezolid and Vancomycin on Biofilms of Viridans Streptococci Isolates from Patients with Endocarditis

Background

Endocarditis, and prosthetic valve endocarditis in particular, is a serious disease with high morbidity and mortality. We investigate the effects of tigecycline, linezolid and vancomycin on biofilms of viridans group streptococci (VGS) isolated from patients with definite native or prosthetic valve endocarditis.

Methods and Results

Ten of 20 VGS blood stream isolates from patients with endocarditis formed biofilms in the microtiter plate biofilm model. The minimal inhibitory concentrations (MIC) for tigecycline, linezolid and vancomycin were determined using the microdilution broth method. Biofilms were grown for 24 hours and were incubated with tigecycline, linezolid and vancomycin at increasing concentrations from 1-128x MIC of the isolate being tested. Biofilm thickness was quantified by measuring the optical density (OD) after dyeing it with crystal violet. The incubation of the biofilms with tigecycline, linezolid or vancomycin resulted in a significant reduction of OD compared to the control biofilm without antibiotic (p<0.05). The optical density ratio (Odr) decreased significantly at 2x MIC for tigecycline, and at 8x MIC for linezolid and vancomycin (p<0.05). Although biofilms persisted even at the highest antibiotic concentrations of 128x MIC, bacterial growth was eradicated starting at concentrations of 16x MIC for vancomycin and of 32x MIC for linezolid, but not for tigecycline, up to a concentration of 128x MIC.

Conclusions

In the present study on viridans streptococci isolated from patients with endocarditis, tigecycline and linezolid reduced the density of the biofilms as effectively as vancomycin. However, linezolid and vancomycin were bactericidal at higher concentrations. Linezolid and vancomycin at very high doses may be useful in the treatment of biofilm-associated diseases caused by VGS infections.

Evaluation of three experimental in vitro models for the assessment of the mechanical cleansing efficacy of wound irrigation solutions

The aim of this study was to compare different wound-rinsing solutions to determine differences in the efficiency and to evaluate three different in vitro models for wound cleansing. Different wound-rinsing solutions (physiological saline solution, ringer lactate solution for wound irrigation, water and a solution containing polihexanide and the surfactant undecylenamidopropyl-betain) were applied on standardised test models (one- and three-chamber model, flow-cell method and a biofilm model), each challenged with three different standardised wound test soils. In the one-chamber model saline showed a better effect on decontaminating proteins than the ringer lactate solution. In the flow-cell method, water performed better than physiological saline solution, whereas ringer lactate solution demonstrated the lowest cleansing effect. No obvious superiority between the two electrolyte-containing solutions was detectable in the biofilm model. Unfortunately, it was not possible to assess the protein decontamination qualities of the surfactant-containing solution because of the interference with the protein measurement. The flow-cell method was able to detect differences between different rinse solutions because it works at constant flow mechanics, imitating a wound-rinsing procedure. The three-chamber and the less-pronounced modified one-chamber method as well as the biofilm model had generated inhomogeneous results.

Molecular epidemiology of multidrug-resistant clinical isolates of Acinetobacter baumannii : A 10-year analysis in a large tertiary care university hospital in central Europe with international admissions

Background

Over the last 10 years, multidrug resistant Acinetobacter baumannii has been spreading worldwide as emerging microorganisms that negatively impact on the outcome of in-hospital patients.

Methods

Between 2007 and 2016, all isolates of patients of the Vienna General Hospital (VGH), tested positive for multidrug resistant Acinetobacter baumannii (MDR A. baumannii) strains, were investigated with respect to their genetic relationship. Patient medical histories were reviewed in order to collect discriminating factors related to MDR A. baumannii colonization or infection.

Results

A total of 79 isolates of 76 patients were obtained. For 44 of them (55.7%) the first diagnosis ward was an intensive care unit (ICU). A total of 10 genotype clusters were identified and 35 cases (44.3%) of in-hospital acquisition in our institution could be detected. Multidrug resistant Acinetobacter baumannii isolates were acquired before admission to our hospital in 44 cases (55.7%) and in 31 (70.5%) they belonged to patients who had previous exposure to the healthcare setting of high prevalence countries for MDR A. baumannii.

Conclusion

Patients admitted to our hospital with a previous healthcare contact in a high prevalence country for multidrug resistant Acinetobacter baumannii should be screened before admission to high-risk wards. Isolation of these patients until microbiological results could reduce negative outcome in these wards.

Does Extracellular DNA Production Vary in Staphylococcal Biofilms Isolated From Infected Implants versus Controls?

BACKGROUND

Prosthetic implant infections caused by Staphylococcus aureus and epidermidis are major challenges for early diagnosis and treatment owing to biofilm formation on the implant surface. Extracellular DNA (eDNA) is actively excreted from bacterial cells in biofilms, contributing to biofilm stability, and may offer promise in the detection or treatment of such infections.

QUESTIONS/PURPOSES

(1) Does DNA structure change during biofilm formation? (2) Are there time-dependent differences in eDNA production during biofilm formation? (3) Is there differential eDNA production between clinical and control Staphylococcal isolates? (4) Is eDNA production correlated to biofilm thickness?

METHODS

We investigated eDNA presence during biofilm formation in 60 clinical and 30 control isolates of S aureus and S epidermidis. The clinical isolates were isolated from patients with infections of orthopaedic prostheses and implants: 30 from infected hip prostheses and 30 from infected knee prostheses. The control isolates were taken from healthy volunteers who had not been exposed to antibiotics and a hospital environment during the previous 3 and 12 months, respectively. Control S epidermidis was isolated from the skin of the antecubital fossa, and control S aureus was isolated from the nares. For the biofilm experiments the following methods were used to detect eDNA: (1) fluorescent staining with 4',6-diamidino-2-phenylindole (DAPI), (2) eDNA extraction using a commercial kit, and (3) confocal laser scanning microscopy for 24-hour biofilm observation using propidium iodide and concanavalin-A staining; TOTO^®-1 and SYTO^® 60 staining were used for observation and quantification of eDNA after 6 and 24 hours of biofilm formation. Additionally antibiotic resistance was described.

RESULTS

eDNA production as observed by confocal laser scanning microscopy was greater in clinical isolates than controls (clinical isolates mean ± SD: 1.84% ± 1.31%; control mean ± SD: 1.17% ± 1.37%; p < 0.005) after 6 hours of biofilm formation. After 24 hours, the amount of eDNA was greater in biofilms of S epidermidis than in biofilms of S aureus (S aureus mean ± SD: 1.35% ± 2.0%; S epidermidis mean ± SD: 6.42% ± 10.6%; p < 0.05). Clinical isolates of S aureus and S epidermidis produced more eDNA than control isolates at 6 hours of biofilm formation. The extraction method also showed that clinical isolates produced substantially greater amounts of eDNA than controls.

CONCLUSIONS

S aureus and S epidermidis exhibit a differential production of DNA with time. Clinical isolates associated with implant infections produce greater amounts of eDNA than controls. Future research might focus on the diagnostic value of eDNA as a surrogate laboratory marker for biofilm formation in implant infections.

CLINICAL RELEVANCE

eDNA should be considered as a potential future diagnostic tool or even a possible target to modify biofilms for successful treatment of biofilm-associated infections.

Sonication culture improves microbiological diagnosis of modular megaprostheses

Modular megaprostheses are known for high infection rates followed by high rates of revisions. Microbial biofilms growing adherently on prosthetic surfaces may inhibit the detection of the pathogens causing prosthetic joint infections. We sought to answer the following questions: Does sonication culture (SC) improve the microbiological diagnosis of periprosthetic infections of megaprostheses compared to conventional tissue culture (TC)? Which pathogens were detected on the surface of megaprostheses with either SC or TC and do the findings help to identify low-grade infections? Included were 31 patients with modular megaprostheses, whose implant had been explanted due to suspected joint infection or revision surgery. SCs were performed according to the protocol by Trampuz et al. The diagnosis of infection was evaluated according to the definition of the Musculoskeletal Infection Society. The sensitivity of SC was 91.3% compared to 52.2% for TC and the specificity was 100% for SC and TC (p = 0.004). Under preoperative antibiotic therapy, the sensitivity of SC was 83.3% while the sensitivity of TC was 50%. Without preoperative antibiotic therapy the sensitivity of SC was 100% compared to 54.5% for TC. In nine cases, SCs detected microorganisms, while TC was negative. Detected bacteria were Staphylococcus epidermidis in four, Micrococcus species in one, Finegoldia magna in one, Brevibacterium casei in one, Pseudomonas fluorescens in one, and Enterococcus faecium in one. SC is a reliable method for dislodging pathogens from orthopedic implants. The SC of modular megaprostheses showed significantly higher pathogen detection than the periprosthetic TC, especially for low virulence pathogens. © 2016 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 35:1383-1387, 2017.

Strategies to enhance rational use of antibiotics in hospital: a guideline by the German Society for Infectious Diseases

Introduction

In the time of increasing resistance and paucity of new drug development there is a growing need for strategies to enhance rational use of antibiotics in German and Austrian hospitals. An evidence-based guideline on recommendations for implementation of antibiotic stewardship (ABS) programmes was developed by the German Society for Infectious Diseases in association with the following societies, associations and institutions: German Society of Hospital Pharmacists, German Society for Hygiene and Microbiology, Paul Ehrlich Society for Chemotherapy, The Austrian Association of Hospital Pharmacists, Austrian Society for Infectious Diseases and Tropical Medicine, Austrian Society for Antimicrobial Chemotherapy, Robert Koch Institute.

Materials and methods

A structured literature research was performed in the databases EMBASE, BIOSIS, MEDLINE and The Cochrane Library from January 2006 to November 2010 with an update to April 2012 (MEDLINE and The Cochrane Library). The grading of recommendations in relation to their evidence is according to the AWMF Guidance Manual and Rules for Guideline Development.

Conclusion

The guideline provides the grounds for rational use of antibiotics in hospital to counteract antimicrobial resistance and to improve the quality of care of patients with infections by maximising clinical outcomes while minimising toxicity. Requirements for a successful implementation of ABS programmes as well as core and supplemental ABS strategies are outlined. The German version of the guideline was published by the German Association of the Scientific Medical Societies (AWMF) in December 2013.

Prospective microbiologic evaluation of the forceps elevator in closed-channel duodenoscopes after reprocessing

BACKGROUND

Endoscopes are well-known sources of bacterial transmission in health care facilities offering endoscopy services. The association between multidrug-resistant bacterial infections in patients who had undergone an endoscopic retrograde cholangiopancreatography procedure with reprocessed duodenoscopes has been much discussed. Bacterial contamination of duodenoscopes has been attributed to difficulties with reprocessing these devices, specifically the distal end of the scope, which features a movable forceps elevator. In light of a recent Food and Drug Administration warning letter to Olympus regarding their closed-channel duodenoscope model TJF-Q180V, the aim of our study was to prospectively evaluate the efficacy and safety of our current reprocessing procedures with regard to the TJF-Q180V duodenoscope models used in our hospital.

METHODS

From August 2015-March 2016, we prospectively collected microbiologic surveillance samples from 6 TJF-Q180V model duodenoscopes in routine use at the Division of Gastroenterology and Hepatology using the ESwab collection system (COPAN Diagnostics Inc, Murrieta, CA).

RESULTS

A total of 237 microbiologic samples from the forceps elevator were obtained during the survey period. None of the samples yielded microorganism growth.

CONCLUSION

These findings suggest that when following a diligent and validated reprocessing standard in accordance with manufacturer's recommendations, closed-channel endoscope models can still be used. Nevertheless, validated adaptions of current closed-channel duodenoscope models are needed to allow for simple and safe reprocessing. Furthermore, comprehensive postmarket surveillance needs to be established.

Incidence and characteristics of invasive fungal diseases in allogeneic hematopoietic stem cell transplant recipients: a retrospective cohort study

Background

Allogeneic hematopoietic stem cell transplant (HSCT) recipients experience an increased risk for invasive fungal diseases (IFDs).

Methods

This retrospective cohort study at the Medical University of Vienna aspired to assess the incidence, characteristics and the outcome of IFDs as well as the associated risk factors in a setting where only 43 % of patients were given systemic antifungal prophylaxis during aplasia. IFDs were classified as probable or proven according to the EORTC/MSG consensus group. All adult patients (n = 242) receiving an allogeneic HSCT at the University Hospital of Vienna from January 2009 to December 2013 were enrolled.

Results

The primary outcome of this study was the one-year incidence for IFDs after HSCT, which was 10.3 % (25/242). Overall 28 patients experienced an IFD – 20 probable and 8 proven – with invasive aspergillosis being the predominant IFD (n = 18), followed by invasive candidiasis (n = 7) and pneumocystis pneumonia (n = 3). Patients with an IFD were more likely to be admitted to an intensive care unit (64 % versus 12 %, p < 0.0001) and had a significantly higher mortality in the first year after HSCT (48 % versus 25 %, p = 0.02). Multivariate regression analysis revealed that intensified immunosuppressive therapy (high-dose cortisone and basiliximab or etanercept) because of severe graft-versus-host disease (adjusted odds ratio (AOR) 3.6, p = 0.01) and transplant-associated microangiopathy (AOR 3.7, p = 0.04) were associated with an increased risk for IFD, while antifungal prophylaxis given during aplasia and post-engraftment was associated with a decreased risk (AOR 0.3, p = 0.02).

Conclusions

We documented a one-year incidence for IFDs of 10.3 % and no selection of rare pathogens at a centre with moderate use of antifungal prophylaxis. Intensified immunosuppressive therapy and transplant-associated microangiopathy were significant risk factors for IFDs.

Non-linear significant relationship between use of glycopeptides and isolation of vancomycin-resistant Enterococcus species in a university hospital setting

BACKGROUND

Emergence of colonization and infection with vancomycin-resistant enterococci (VRE) has become a worldwide challenge. To investigate whether the increasing incidence of VRE isolation can be correlated with use of glycopeptides in the hospital setting, we conducted a hospital-wide two-year study in the university hospital of Vienna.

METHODS

Within the period from January 2011 through December 2012 all patients with isolation of invasive or non-invasive VRE were retrospectively included. Specialty-specific data concerning the consumption of vancomycin and teicoplanin, fluoroquinolones and third generation cephalosporins in defined daily doses (DDDs) from June 2010 through May 2012 were extracted from the hospital pharmacy computer system. To assess the relationship between the usage of those antibiotics and the incidence of VRE (VRE-rate per 10 000 patients) a Poisson regression was performed.

FINDINGS

In the study period 266 patients were colonized or infected with VRE. Specialty-specific VRE isolation was as follows: general surgical units (44 patients), bone marrow transplant unit (35 patients), general medical units (33 patients), cardiothoracic surgery (27 patients), nephrology (26 patients), haematooncology (22 patients), gastroenterology (17 patients), urology (17 patients), and the infectious diseases unit (11 patients). Hospital-wide consumption of glycopeptides was higher for teicoplanin than for vancomycin (26 242 versus 8677 DDDs). Specialty-specific VRE incidence significantly increased with the use of glycopeptides, fluoroquinolones or third generation cephalosporins (p < 0.001). The results of the Poisson regression for vancomycin (p = 0.0018) and teicoplanin (p < 0.0001) separately were both highly significant. Spearman's correlation coefficient indicated a strong correlation between the two variables (rho = 0.8).

CONCLUSION

Overall usage of glycopeptides, fluoroquinolones or third generation cephalosporins contributed to the emergence of VRE in the hospital setting.

The strength of coughing may forecast the likelihood of spread of multi-drug resistant microorganisms from the respiratory tract of colonized patients

Background

Current recommendations indicate that patients who are coughing and have multidrug resistant microorganisms (MDROs) in their sputum are considered to be shedders and should be cared for in single room isolation at least until symptoms resolve. Airborne spread and subsequent contamination of surfaces adjacent to patients may contribute to transmission. Hence, isolation measures for patients colonized or infected with MDRO at their respiratory tract are intended to interrupt such transmission. However, the potential for microbial shedding in patients with MDRO-positive microbiological reports from their respiratory tract and factors justifying the need for single room isolation are viewed controversially.

Methods

Cough aerosol produced by patients colonized with MDROs was measured for viable counts. Descriptive analysis together with logistic regression analysis was performed to assess the impact of strength of cough on growth of MDRO on culture plates.

Results

In 18% (23/128) MDRO were transmitted. Multivariate analysis revealed that strength of cough significantly predicts the yield of MDRO on culture plates (P = 0.012).

Conclusion

Based on these results it can be concluded that risk stratification for decision of single room isolation of patients colonized or infected with MDROs at their respiratory tract may also take the severity of cough into consideration. However, more work is required in order to assess the severity of cough objectively.

Successful implementation of infection control strategies prevents P. aeruginosa transmission among cystic fibrosis patients inside the hospital

Background: The aim of this study was to characterise the epidemiology of P. aeruginosa isolated from cystic fibrosis (CF) patients at the Vienna General Hospital (VGH) by molecular genetic fingerprinting in order to understand transmission ways and to evaluate the established infection control protocols.

Methods: The outpatient clinic for CF patients at the VGH cares for children and adolescents up to the age of 18 years. Among an average of 139 patients cared for at the clinic, 41 were tested positive for P. aeruginosa during the study period. Fifty P. aeruginosa isolates, obtained between August 2010 and March 2012 from routine examinations of CF patients, were subject to molecular characterization using the DiversiLab^® method.

Results: 42 distinguishable molecular-biological patterns were identified, 7 of which were found multiple times. 40 out of 42 genotypes were retrieved from single patients only, while two patterns were present in two patients each.

Nine patients presented with two or more phenotypically diverse P. aeruginosa isolates. In five of these cases the retrieved isolates belonged to the same genotype.

Conclusion: The broad genetic heterogeneity of P. aeruginosa in the studied patient population suggests that the majority of CF patients cared for at the VGH acquire P. aeruginosa from environmental sources. It may be concluded that implemented infection control guidelines have been successful in preventing nosocomial transmission of P. aeruginosa among CF patients within the VGH and patient-to-patient transmission outside the hospital. Chronic polyclonal infection/colonization was rare in the study population.