Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 20 de 34
Filter
1.
Diagn Microbiol Infect Dis ; 106(4): 115991, 2023 Aug.
Article in English | MEDLINE | ID: mdl-37295183

ABSTRACT

In the context of the current SARS-CoV-2 pandemic, reliable and cost-efficient screening and testing strategies are crucial to prevent disease transmission and reduce socioeconomic losses. To assess the efficiency of a rapid antigen test (RAT)-based SARS-CoV-2 contact-tracing and screening regime, we conducted a retrospective analysis of RAT and polymerase chain reaction (PCR) test data over a 1-year period, assessed test characteristics and estimated cost-effectiveness. The RAT had a sensitivity of 70.2% overall and 89.3% for people with a high risk of infectivity. We estimated inpatient treatment and quarantined healthcare worker costs of over € 5860.83, whereas the cost of identifying one SARS-CoV-2 positive person by RAT for our patient cohort was € 1210.75. In contrast, the estimated respective PCR cost was € 5043.32. Therefore, a RAT-based contract tracing and screening regime may be an efficient and cost-effective way to contribute to the early identification and prevention of SARS-CoV-2 transmission.


Subject(s)
COVID-19 , SARS-CoV-2 , Humans , COVID-19/diagnosis , COVID-19/epidemiology , Contact Tracing , Cost-Effectiveness Analysis , Retrospective Studies , Hospitals
2.
PLoS One ; 17(11): e0268863, 2022.
Article in English | MEDLINE | ID: mdl-36350807

ABSTRACT

BACKGROUND: The reprocessing of daily used medical devices is often inadequate, making them a potential source of infection. In addition, there are usually no consistent and technically standardized procedures available for this purpose. Hence, the aim of this study is to analyze the bacterial contamination and the effectiveness of Ultraviolet light-based (UV light-based) reprocessing of daily used medical devices. MATERIAL AND METHODS: Six different everyday medical devices (20 each; stethoscopes, tourniquets, bandage scissors, reflex hammers, tuning forks, and nystagmus glasses) were tested for bacterial contamination. All medical devices were then exposed to UV-C light for 25 seconds. Medical devices with a smooth surface were pre-cleaned with a water-based wipe. Contact samples were taken before and after reprocessing. RESULTS: Immediately after clinical use, 104 of 120 contact samples showed an average bacterial contamination of 44.8±64.3 colony forming units (CFU) (0-300 CFU), also including potentially pathogenic bacteria. Two further culture media were completely overgrown with potentially pathogenic bacteria. The stethoscopes were found to have the highest average contamination of 90±91.6 CFU. After reprocessing, 118 of 120 samples were sterile, resulting in an average residual contamination of 0.02±0.1 CFU in two samples, whereby only bacteria of the ordinary skin flora were found. CONCLUSION: The present study shows the potentially clinically relevant bacterial contamination of everyday used medical devices. The reprocessing method tested here using UV light appears to be a suitable method for disinfection, especially for objects that up to now have been difficult to disinfect or cannot be disinfected in a standardized manner.


Subject(s)
Equipment Contamination , Ultraviolet Rays , Equipment Contamination/prevention & control , Disinfection/methods , Bacteria , Drug Contamination
3.
Can J Infect Dis Med Microbiol ; 2022: 6978661, 2022.
Article in English | MEDLINE | ID: mdl-36317154

ABSTRACT

Face masks and respirators are commonly used to prevent the transmission of infectious diseases that spread by respiratory droplets and aerosols. However, there is still uncertainty about the protective effect of the different types of masks against virus containing aerosols. To determine the as-worn bioaerosol protection efficacy of different face coverings and estimate the possible protective function against airborne diseases, we challenged different respirators and medical masks on a standardized dummy head with a bioaerosol containing MS2 bacteriophages as virus surrogates. In our experiments, FFP2 respirators showed the highest filtration efficacy 94 ± 4 (SD) % followed by medical masks 93 ± 3 (SD) % and KN95 respirators 90 ± 7 (SD) %. Nevertheless, we found no statistically significant difference between respirators and medical masks in terms of provided protection against infective aerosols. Our findings indicate that both respirators and medical masks provide a high as-worn bioaerosol protection efficacy against virus containing aerosols, and therefore, a very high protection against airborne diseases. Considering the higher comfort, better availability, and lower price of medical masks in contrast to respirators, it is recommendable to use medical face masks especially in low risk situations and in general public.

4.
Antimicrob Resist Infect Control ; 11(1): 140, 2022 11 11.
Article in English | MEDLINE | ID: mdl-36369056

ABSTRACT

BACKGROUND: The first detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in Germany was reported in early February 2020. In addition, extensive control measures on the coronavirus disease 2019 (COVID-19) pandemic have been placed in Germany since March 2020. These include contact and travel restrictions, distance rules, mandatory wearing of face masks and respirators, cancellation of mass events, closures of day-care centers, schools, restaurants and shops, isolation measures, and intensified infection control measures in medical and long-term care facilities. Changes in demand or access to health care services and intensified control measures can lead to changes in transmission dynamics and imply effects on the overall occurrence of infectious diseases in hospitals. METHODS: To analyze the impact of infection control measures implemented in public on infectious diseases in hospitals, surveillance data from Marburg University Hospital were analyzed retrospectively. The analysis was conducted from January 2019 to June 2021, referred to hospital occupancy and mobility data in the county of Marburg-Biedenkopf, and correlated to control measures in hospitals and the general population. RESULTS: The COVID-19 pandemic and associated measures immediately impacted the occurrence of infectious diseases at the Marburg University Hospital. Significant changes were detected for virus-associated respiratory and gastrointestinal diseases. The massive drop in norovirus infections was significantly affected by the onset of the pandemic (P = 0.028). Similar effects were observed for rotavirus (up to - 89%), respiratory syncytial virus (up to - 98%), and adenovirus infections (up to - 90%). The decrease in gastrointestinal and respiratory virus detection rates was significantly affected by the decline in mobility (P < 0.05). Of note, since April 2020, there have been no detected influenza cases. Furthermore, Clostridioides difficile-related infections declined after late 2020 (- 44%). In contrast, no significant changes were detected in the prevalence of susceptible and drug-resistant bacterial pathogens. In particular, the detection rates of methicillin-resistant Staphylococcus aureus isolates or multidrug resistant (MDR) and extended drug resistant (XDR) bacteria remained constant, although the consumption of hand disinfectants and protective equipment increased. CONCLUSIONS: The COVID-19 pandemic and associated public health measures had a significant impact on infectious diseases and the detection of pathogens at the Marburg University Hospital. Significant changes were observed for community transmissible infections, while no such effects on pathogens primarily associated with nosocomial transmission could be detected.


Subject(s)
COVID-19 , Methicillin-Resistant Staphylococcus aureus , Humans , Pandemics/prevention & control , SARS-CoV-2 , COVID-19/epidemiology , COVID-19/prevention & control , Public Health , Retrospective Studies , Infection Control , Hospitals
5.
Front Oral Health ; 3: 974644, 2022.
Article in English | MEDLINE | ID: mdl-35979536

ABSTRACT

Various dental, maxillofacial, and orthopedic surgical procedures (DMOSP) have been known to produce bioaerosols, that can lead to the transmission of various infectious diseases. Hence, a systematic review (SR) aimed at generating evidence of aerosols generating DMOSP that can result in the transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), further investigating their infectivity and assessing the role of enhanced personal protective equipment (PPE) an essential to preventing the spreading of SARS-CoV-2 during aerosol-generating procedures (AGPs). This SR was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses statement (PRISMA) guidelines based on a well-designed Population, Intervention, Comparison, Outcomes and Study (PICOS) framework, and various databases were searched to retrieve the studies which assessed potential aerosolization during DMOSP. This SR included 80 studies (59 dental and 21 orthopedic) with 7 SR, 47 humans, 5 cadaveric, 16 experimental, and 5 animal studies that confirmed the generation of small-sized < 5 µm particles in DMOSP. One study confirmed that HIV could be transmitted by aerosolized blood generated by an electric saw and bur. There is sufficient evidence that DMOSP generates an ample amount of bioaerosols, but the infectivity of these bioaerosols to transmit diseases like SARS-CoV-2 generates very weak evidence but still, this should be considered. Confirmation through isolation and culture of viable virus in the clinical environment should be pursued. An evidence provided by the current review was gathered by extrapolation from available experimental and empirical evidence not based on SARS-CoV-2. The results of the present review, therefore, should be interpreted with great caution.

6.
Article in English | MEDLINE | ID: mdl-35328933

ABSTRACT

Background: The reprocessing of medical devices has become more complex due to increasing hygiene requirements. Previous studies showed satisfactory bactericidal disinfection effects of UV-C light in rigid and flexible endoscopes. Especially in the context of the current COVID-19 pandemic, virucidal properties are of high importance. In the present study, the virucidal efficacy of UV-C light surface disinfection was analyzed. Methods: MS-2 bacteriophages were applied to the test samples and irradiated by UV-C light using the UV Smart D25 device; unirradiated test samples were used as controls. A dilution series of the samples was mixed with 1 × 108 Escherichia coli and assayed. Results: 8.6 × 1012 pfu could be harvested from the unprocessed test samples. In the control group without UV-C exposure, a remaining contamination of 1.2 × 1012 pfu was detected, resulting in a procedural baseline reduction rate with a LOG10 reduction factor of 0.72. The LOG10 reduction factor was found to be 3.0 after 25 s of UV-C light exposure. After 50 and 75 s of UV-C radiation LOG10 reduction factors 4.2 and 5.9, respectively, were found, with all reductions being statistically significantly different to baseline. Conclusions: The tested UV system seems to provide a significant virucidal effect after a relatively short irradiation time.


Subject(s)
Bacteriophages , COVID-19 , COVID-19/prevention & control , Disinfection/methods , Humans , Pandemics , Ultraviolet Rays
7.
Article in English | MEDLINE | ID: mdl-34199085

ABSTRACT

Due to the SARS-CoV-2 pandemic, dental treatment performed by undergraduate students at the University of Marburg/Germany was immediately stopped in spring 2020 and stepwise reinstalled under a new hygiene concept until full recovery in winter 2020/21. Patient treatment in the student courses was evaluated based on three aspects: (1) Testing of patients with a SARS-CoV-2 Rapid Antigen (SCRA) Test applied by student assistants (SA); (2) Improved hygiene regimen, with separated treatment units, cross-ventilation, pre-operative mouth rinse and rubber dam application wherever possible; (3) Recruitment of patients: 735 patients were pre-registered for the two courses; 384 patients were treated and a total of 699 tests with the SCRA test were performed by SAs. While half of the patients treated in the course were healthy, over 40% of the patients that were pre-registered but not treated in the course revealed a disease being relevant to COVID (p < 0.001). 46 patients had concerns to visit the dental hospital due to the increase of COVID incidence levels, 14 persons refused to be tested. The presented concept was suitable to enable patient treatment in the student course during the SARS-CoV-2 pandemic.


Subject(s)
COVID-19 , Pandemics , Education, Dental , Hospitals , Humans , Pandemics/prevention & control , SARS-CoV-2
8.
Antimicrob Resist Infect Control ; 10(1): 102, 2021 07 02.
Article in English | MEDLINE | ID: mdl-34215330

ABSTRACT

INTRODUCTION: In late 2019, a novel coronavirus was detected in China. Supported by its respiratory transmissibility, even by people infected without symptomatic disease, this coronavirus soon began to rapidly spread worldwide. BACKGROUND: Many countries have implemented different infection control and containment strategies due to ongoing community transmission. In this context, contact tracing as well as adequate testing and consequent quarantining of high-risk contacts play leading roles in containing the virus by interrupting infection chains. This approach is especially important in the hospital setting where contacts often cannot be avoided and physical distance is usually not possible. Furthermore, health care workers (HCWs) usually have contact with a variety of vulnerable people, making it essential to identify infections among hospital employees as soon as possible to interrupt the rapid spread of SARS-CoV-2 in the facility. Several electronic tools for contact tracing, such as specific software or mobile phone apps, are available for the public health sector. In contrast, contact tracing in hospitals often has to be carried out without helpful electronic tools, and an enormous amount of human resources is typically required. AIM: For rapid contact tracing and effective infection control and management measures for HCWs in hospitals, adapted technical solutions are needed. METHODS: In this study, we report the development of our containment strategy to a web-based contact tracing and rapid point-of-care-testing workflow. RESULTS/CONCLUSION: Our workflow yielded efficient control of the rapidly evolving situation during the SARS-CoV-2 pandemic from May 2020 until January 2021 at a German University Hospital.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/transmission , Computer Communication Networks , Contact Tracing/methods , Infectious Disease Transmission, Patient-to-Professional , Pandemics , Point-of-Care Testing , SARS-CoV-2 , COVID-19/epidemiology , Germany/epidemiology , Hospitals, University , Humans , Infection Control/methods , Infectious Disease Transmission, Professional-to-Patient/prevention & control , Mobile Applications , Personnel, Hospital , Real-Time Polymerase Chain Reaction , Retrospective Studies , Seasons , Software , Workflow
10.
J Infect Prev ; 22(1): 12-18, 2021 Jan.
Article in English | MEDLINE | ID: mdl-33841557

ABSTRACT

PURPOSE: This in vitro study was designed to determine if standard antiseptics used for skin and environmental surface cleansing can disrupt the metabolic activity (as a measure of viability) of multidrug-resistant gram-negative bacteria, methicillin-resistant Staphylococcus aureus (MRSA) and vancomycin-resistant Enterococcus isolates within their native biofilms. METHODS: Sixty clinical isolates of multidrug-resistant bacteria were selected for testing in different chlorhexidine gluconate, octenidine, polyhexanide and chloroxylenol concentrations. Metabolic inhibition of biofilm for each clinical isolate was analysed using a biofilm viability assay. RESULTS: Chlorhexidine gluconate (mean = 83.8% ± 9.8%) and octenidine (mean = 84.5% ± 6.8%) showed the greatest efficacy against biofilms of the tested microorganisms, with the greatest efficacies against MRSA. The antiseptics demonstrated the least efficacy against biofilms of Pseudomonas aeruginosa. CONCLUSION: Chlorhexidine gluconate and octenidine showed the greatest level of bacterial metabolic inhibition and were statistically equivalent. Polyhexanide was more effective than chloroxylenol, but both were inferior to chlorhexidine gluconate and octenidine against the tested organisms.

11.
Eur Arch Otorhinolaryngol ; 278(10): 4075-4080, 2021 Oct.
Article in English | MEDLINE | ID: mdl-33713189

ABSTRACT

BACKGROUND: Reprocessing of flexible endoscopes (FEs) is often expensive, time consuming, and becomes increasingly complex, due to rising demands of hygiene. After beneficial results in reprocessing of rigid endoscopes using Impelux™ UV-C light technology, we tested the same method for reprocessing of FEs without working channel. MATERIALS AND METHODS: Testing was performed on FEs without working channel after routine clinical use (transnasal flexible endoscopy). Disinfection consisted of mechanical precleaning and 60 s exposure to Impelux™ UV-C light technology. Bacterial contamination was tested on 50 FEs before and after disinfection. Further 50 FEs regarding protein residuals. The absolute effectiveness of the D60 was tested on 50 test bodies (RAMS) with a standardized contamination of 107 colony-forming units (CFU) of Enterococcus faecium. RESULTS: The FEs were contaminated with a high average value of 916.7 CFU (± 1057 CFU) after clinical usage. After reprocessing, an average contamination of 2.8 CFU (± 1.6) on 14% (n = 7) of the FEs was detected consisting of non-pathogenic species, the remaining FE were sterile. After reprocessing, all FEs were protein-free (< 1 µg). The artificially contaminated test bodies showed no remaining bacterial contamination after disinfection, resulting in an average absolute germ reduction of about 107 CFU. CONCLUSION: Impelux™ UV-C light technology efficiently reduces bacterial contamination of FEs and might be useful in daily practice.


Subject(s)
Equipment Contamination , Otolaryngology , Animals , Disinfection , Endoscopes , Equipment Contamination/prevention & control , Male , Sheep , Ultraviolet Rays
12.
PLoS One ; 16(3): e0248099, 2021.
Article in English | MEDLINE | ID: mdl-33657178

ABSTRACT

Since the appearance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the question regarding the efficacy of various hygiene measures and the use of personal protective equipment (PPE) has become the focus of scientific and above all public discussion. To compare respirators, medical face masks, and cloth masks and determine if it is recommendable to wear face masks to protect the individual wearer of the mask from inhaling airborne particles, we challenged 29 different masks with aerosols and tested the pressure drop as a surrogate for breathing resistance owing to the mask material. We found that Type II medical face masks showed the lowest pressure drop (12.9±6.8 Pa/cm2) and therefore additional breathing resistance, whereas respirators such as the KN95 (32.3±7.0 Pa/cm2) and FFP2 (26.8±7.4 Pa/cm2) showed the highest pressure drops among the tested masks. The filtration efficacy of the mask material was the lowest for cloth masks (28±25%) followed by non-certified face masks (63±19%) and certified medical face masks (70±10%). The materials of the different respirators showed very high aerosol retentions (KN95 [94±4%] and FFP2 [98±1%]). For evaluating the as-worn filtration performance simulating real live conditions each mask type was also tested on a standardized dummy head. Cloth masks and non-EN-certified face masks had the worst as-worn filtration efficacies among the tested masks, filtering less than 20% of the test aerosol. Remarkably, certified type II medical face masks showed similar (p>0.5) as-worn filtration results (47±20%) than KN95 masks (41±4%) and FFP2 masks (65±27%), despite having a lower pressure drop. Face shields did not show any significant retention function against aerosols in our experiment. Our results indicate that it seems recommendable to wear face masks for providing base protection and risk reduction against inhaling airborne particles, in low-risk situations. In our study, especially EN 14683 type II certified medical face masks showed protective effectiveness against aerosols accompanied by minimal additional breathing resistance. FFP2 Respirators, on the other hand, could be useful in high-risk situations but require greater breathing effort and therefore physical stress for users.


Subject(s)
COVID-19/transmission , Disease Transmission, Infectious/prevention & control , Masks/trends , Aerosols , COVID-19/epidemiology , Filtration , Humans , Models, Statistical , Occupational Exposure/prevention & control , Personal Protective Equipment/trends , Respiratory Protective Devices/virology , SARS-CoV-2/pathogenicity
13.
Transfus Med Hemother ; 47(3): 254-263, 2020 Jun.
Article in English | MEDLINE | ID: mdl-32595430

ABSTRACT

BACKGROUND: The microbiological control of cellular products sometimes causes significant procedural issues for quality control laboratories. According to the European Pharmacopoeia (EP), the microbiological control of cellular products requires a 7- to 14-day incubation period at two different incubation temperatures using aerobic and anaerobic growth media. However, the suitability of these test conditions for efficient quality control can be influenced by many conditions, such as the expected microbial spectrum of contamination or the texture and composition of the cellular product. Because of interference, direct inoculation and membrane filtration as reference methods of pharmacopoeia are largely unsuitable for the microbiological control of cellular products; therefore, alternative and, above all, automated methods are the focus of interest. OBJECTIVE: The aim of our study was to evaluate the method suitability and possible effects of cell matrix, incubation temperature, and oxygen pressure on the detection performance of automated culture systems. METHODS: The BacT/ALERT® 3DTM Dual T system (bioMérieux, Nürtingen, Germany) was used to evaluate the factors influencing automated microbiological control of cellular products. The tests were performed using microbial strains recommended by the EP for microbiological method suitability testing and additional relevant possible contaminants of human-derived stem-cell products under varying culture and cell matrix conditions. RESULTS: All contaminants were detected by the system in the required period of 2-5 days. Low incubation temperatures (22°C) had overall negative effects on the detection kinetics of each type of microbial contamination. The adverse effects of the accompanying cell matrix on the detection properties of the system could be compensated in our study by incubation at 32°C in both the aerobic and the anaerobic culture conditions. CONCLUSION: Automated culture techniques represent a sufficient approach for the microbiological control of cellular products. The negative effects of the cell matrix and microbial contamination on the detection performance can be compensated by the application of variable culture conditions in the automated culture system.

14.
Eur Arch Otorhinolaryngol ; 277(8): 2363-2369, 2020 Aug.
Article in English | MEDLINE | ID: mdl-32358650

ABSTRACT

BACKGROUND: Reprocessing of endoscopes becomes increasingly complex, due to rising demands of hygiene. Established methods are often expensive/time-consuming. Recent studies suggest beneficial aspects of disinfection by UV light. In this study we analyzed the efficiency of UV light disinfection of rigid otorhinolaryngological endoscopes. MATERIALS AND METHODS: After mechanical pre-cleaning, the endoscopes were decontaminated for 25 s in the D25 using Impelux™ UV C light technology (UV Smart B.V., Delft, The Netherlands). First, the surface contact samples were taken from 50 used endoscopes to evaluate the bacterial load. Additionally, surface contact samples were taken from further 50 used endoscopes after reprocessing with the D25. Another 50 endoscopes were tested on protein residuals. Furthermore, the absolute effectiveness of the D25 was tested on 50 test bodies (RAMS) with a standardized contamination of 107 colony-forming units (CFU) of Enterococcus faecium. RESULTS: The used endoscopes showed a high bacterial contamination with an average value of 66.908 (± 239.215) CFU. After reprocessing, only a minimal contamination on 10% (n = 5) of the endoscopes with a mean value of 0.12 CFU (± 0.39) was found, resulting in a log-5 reduction in a clinical environment. The documented bacteria were components of the normal skin flora. All tested endoscopes were practically protein-free (< 1 µg). Furthermore, the average absolute germ reduction of the D25 was about 106 CFU on the tested RAMS. CONCLUSION: The D25 UV light system seems to be an effective device for the reprocessing of rigid ORL endoscopes, and therefore, might be suitable for the usage in clinical practice on site.


Subject(s)
Disinfection , Otolaryngology , Animals , Decontamination , Endoscopes , Equipment Contamination/prevention & control , Male , Netherlands , Sheep , Ultraviolet Rays
15.
J Antimicrob Chemother ; 74(12): 3473-3480, 2019 12 01.
Article in English | MEDLINE | ID: mdl-31504593

ABSTRACT

BACKGROUND: Infection and colonization with multi-resistant Acinetobacter baumannii causes therapeutic and economic problems in the nosocomial setting. Due to the sensitivity issue of screening schemes for A. baumannii, it is difficult to implement adequate transmission prevention measures. The high discriminatory power of WGS for transmission-chain analysis provides us with the necessary tool to study and identify transmission events. We retrospectively sequenced and analysed 39 A. baumannii isolates from 2012-15 to search for possible missed transmission events. METHODS: Molecular typing by WGS was performed for non-repetitive (n=39) carbapenem-resistant A. baumannii. Retrospective assessment of patient records was performed to investigate and confirm possible transmission events. RESULTS: Between July 2012 and September 2015, A. baumannii was isolated from 268 patients, of which 16% (42/268) were carbapenem resistant. Thirty-nine of these isolates were recoverable and sequenced. Fifteen percent (6/39) of these were resistant to all antibiotics tested. Most isolates belong to the circulating IC2 clonal type. SNP analysis revealed four potential outbreak clusters. Two of these clusters showed high concordance with the local spatio-temporal epidemiology, suggesting that transmission events were very likely. CONCLUSIONS: Our data suggest that there were two independent transmission events, which would have been missed by conventional MLST owing to high clonality. The routine implementation of WGS can optimize surveillance and initiation of suitable containment measures. In addition, emerging resistance to salvage therapy is a major therapeutic problem and should be monitored closely.


Subject(s)
Acinetobacter Infections/transmission , Acinetobacter baumannii/classification , Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Drug Resistance, Multiple, Bacterial , Acinetobacter baumannii/drug effects , Bacterial Typing Techniques , Cross Infection/microbiology , DNA, Bacterial/genetics , Disease Outbreaks , Electrophoresis, Gel, Pulsed-Field , Female , Germany , Humans , Male , Microbial Sensitivity Tests , Middle Aged , Multilocus Sequence Typing , Retrospective Studies , Whole Genome Sequencing
16.
J Geophys Res Biogeosci ; 124(5): 1230-1247, 2019 May.
Article in English | MEDLINE | ID: mdl-31341754

ABSTRACT

Thermokarst lake landscapes are permafrost regions, which are prone to rapid (on seasonal to decadal time scales) changes, affecting carbon and nitrogen cycles. However, there is a high degree of uncertainty related to the balance between carbon and nitrogen cycling and storage. We collected 12 permafrost soil cores from six drained thermokarst lake basins (DTLBs) along a chronosequence north of Teshekpuk Lake in northern Alaska and analyzed them for carbon and nitrogen contents. For comparison, we included three lacustrine cores from an adjacent thermokarst lake and one soil core from a non thermokarst affected remnant upland. This allowed to calculate the carbon and nitrogen stocks of the three primary landscape units (DTLB, lake, and upland), to reconstruct the landscape history, and to analyze the effect of thermokarst lake formation and drainage on carbon and nitrogen stocks. We show that carbon and nitrogen contents and the carbon-nitrogen ratio are considerably lower in sediments of extant lakes than in the DTLB or upland cores indicating degradation of carbon during thermokarst lake formation. However, we found similar amounts of total carbon and nitrogen stocks due to the higher density of lacustrine sediments caused by the lack of ground ice compared to DTLB sediments. In addition, the radiocarbon-based landscape chronology for the past 7,000 years reveals five successive lake stages of partially, spatially overlapping DTLBs in the study region, reflecting the dynamic nature of ice-rich permafrost deposits. With this study, we highlight the importance to include these dynamic landscapes in future permafrost carbon feedback models.

17.
Eur J Clin Microbiol Infect Dis ; 38(8): 1547-1552, 2019 Aug.
Article in English | MEDLINE | ID: mdl-31152264

ABSTRACT

Our study aims to define the epidemiology of carbapenem resistance mechanisms in clinical isolates of Pseudomonas aeruginosa (PA). We evaluated 11,457 clinical PA strains isolated between 2009 and 2015 at the tertiary care University Hospital in Heidelberg, Germany. Thirty-four percent of the isolates (3867/11,457) were MDR (multidrug-resistant), 16% (1816/11,457) were XDR (extensively drug resistant), and less than 1% (82/11,457) had a PDR (pandrug-resistant) profile. Of those, 23% carried a carbapenemase gene (CPM positive) with 12% VIM-2, 10% VIM-1, and less than 1% IMP-1. Comparing MIC (minimal inhibitory concentration) distributions, the mean rank for meropenem, imipenem, gentamicin, and fosfomycin was significantly higher in the CPM-positive group than in the CPM-negative XDR group (p ≤ 0.004). oprD (outer membrane protein) mutations were found in 19/19 tested strains; 12/19 carried a CPM and had a higher mutation rate. Meropenem resistance was mostly associated with the presence of CPM. Only 1/19 strains was meropenem resistant in the absence of CPM genes; nevertheless, it carried an oprD mutation in a strategic site (loop 2). Of 19 CPM-negative strains tested, 7 (36%) showed EP (efflux pumps) hyperexpression versus 12 in the CPM-positive strains. In our study, nearly 50% of the PA isolates exhibited resistance to the tested first-line antibiotics. Our study also demonstrates that carbapenemase genes can be isolated in approximately 23% of XDR PA strains in our population. This finding supports the clinical relevance of PA driven by the possible presence of multiple resistance mechanisms acquired under exposure to antibiotics or by horizontal transfer of resistance genes.


Subject(s)
Anti-Bacterial Agents/pharmacology , Carbapenems/pharmacology , Drug Resistance, Multiple, Bacterial/genetics , Pseudomonas aeruginosa/drug effects , Bacterial Proteins/genetics , Germany/epidemiology , Humans , Membrane Transport Proteins/genetics , Microbial Sensitivity Tests , Mutation , Porins/genetics , Pseudomonas Infections/epidemiology , Pseudomonas Infections/microbiology , Pseudomonas aeruginosa/enzymology , Pseudomonas aeruginosa/genetics , Retrospective Studies , beta-Lactamases/genetics
18.
Fitoterapia ; 129: 237-240, 2018 Sep.
Article in English | MEDLINE | ID: mdl-30031115

ABSTRACT

BACKGROUND: Multidrug-resistant (MDR) bacteria are increasingly causing urinary tract infections (UTI), which has been linked to frequent use of antibiotics. Alternative treatment regimens are urgently needed and natural isothiocyanates (ITC) may represent one. ITCs are natural plant products found in nasturtium (Tropaeoli majoris herba) and horseradish (Armoraciae rusticanae radix). PURPOSE: The objectives were to (1) assess the antimicrobial effects of nature-identical ITCs for UTI treatment caused by uropathogenic E. coli (UPEC), (2) to evaluate a potential influence of antimicrobial resistance on ITC susceptibility, and (3) to test whether ITCs affect UPEC penetration into human uroepithelial cells. METHODS: We tested 217 clinical UPEC isolates, 54.5% of which were classified as MDR, for susceptibility against ITCs. ITC susceptibility testing was performed by broth dilution using a mixture of three synthetic ITCs. Internalization was tested using human T-24 bladder carcinoma cells in an internalization assay co-incubated with UPEC (n = 5) and ITCs. RESULTS: The mean minimal inhibitory concentration (MIC) 90 was 0.17 mg/ml, showing very high susceptibility against ITCs. Interestingly, MDR E. coli were significantly less susceptible than non-MDR strains (p = .01). Internalization of UPEC was decreased by 31.9% in the mean when treated with ITCs. Overall, ITCs exerted a strong antimicrobial activity against clinical UPEC isolates and reduced internalization into uroepithelial cells. CONCLUSION: ITCs might present a promising treatment alternative for UTIs, expressing both high antimicrobial activity as well as blocking the pathogenic process of human cell penetration by UPEC. Clinical studies, however, are needed to confirm activity of ITCs in UTIs in vivo.


Subject(s)
Anti-Bacterial Agents/pharmacology , Isothiocyanates/pharmacology , Phytotherapy , Urinary Tract Infections/drug therapy , Uropathogenic Escherichia coli/drug effects , Cell Line, Tumor , Drug Resistance, Bacterial , Epithelial Cells/drug effects , Humans , Microbial Sensitivity Tests
19.
Ther Clin Risk Manag ; 13: 1239-1245, 2017.
Article in English | MEDLINE | ID: mdl-29033574

ABSTRACT

BACKGROUND: Implant-associated infections are still a feared complication in the field of orthopedics. Bacteria attach to the implant surface and form so-called biofilm colonies that are often difficult to diagnose and treat. Since the majority of studies focus on prosthetic joint infections (PJIs) of the hip and knee, current treatment options (eg, antibiotic prophylaxis) of implant-associated infections have mostly been adapted according to these results. OBJECTIVE: The aim of this study was to evaluate patients with surgical site infections following instrumented stabilization of the spine with regard to detected bacteria species and the course of the disease. PATIENTS AND METHODS: We performed a retrospective single-center analysis of implant-associated infections of the spine from 2010 to 2014. A total of 138 patients were included in the study. The following parameters were evaluated: C-reactive protein serum concentration, microbiological evaluation of tissue samples, the time course of the disease, indication for instrumented stabilization of the spine, localization of the infection, and the number of revision surgeries required until cessation of symptoms. RESULTS: Coagulase-negative Staphylococcus spp. were most commonly detected (n=69, 50%), followed by fecal bacteria (n=46, 33.3%). In 23.2% of cases, no bacteria were detected despite clinical suspicion of an infection. Most patients suffered from degenerative spine disorders (44.9%), followed by spinal fractures (23.9%), non-degenerative scoliosis (20.3%), and spinal tumors (10.1%). Surgical site infections occurred predominantly within 3 months (64.5%), late infections after 2 years were rare (4.3%), in particular when compared with PJIs. Most cases were successfully treated after 1 revision surgery (60.9%), but there were significant differences between bacteria species. Fecal bacteria were more difficult to treat and often required more than 1 revision surgery. CONCLUSION: In summary, we were able to demonstrate significant differences between spinal implant-associated infections and PJIs. These aspects should be considered early on in the treatment of surgical site infections following instrumented stabilization of the spine.

20.
GMS Hyg Infect Control ; 12: Doc11, 2017.
Article in English | MEDLINE | ID: mdl-28840091

ABSTRACT

Background: Spatial isolation is a common infection control measure, but negative psychological effects are often neglected. We investigated which factors influence the perception of single room isolated patients. Methods: In the present correlative cross-sectional study, 32 isolated patients have been interviewed within three departments of the Heidelberg University Hospital, one of Germany's largest hospitals. The following questionnaires were used: 10-Item Big Five Inventory (BFI-10), Positive and Negative Affect Schedule (PANAS), Hospital Anxiety and Depression Scale (HADS) and a self-developed questionnaire to evaluate the individual experience of isolation. Data were analysed using correlation and regression analysis. Results: A significant positive correlation was found between the isolation period and anxiety (r=.42, p<.05). Interestingly, a significant positive correlation was demonstrated between the duration of contact to nursing staff and negative daydreaming (r=.89, p<.01). The activity watching television was associated with higher levels of anxiety (r=.38, p<.05). Surfing the internet had a positive relationship with thinking about beautiful things (r=.41, p<.05). Conclusions: Our study results have implications how to improve the psychological situation of patients during spatial isolation. Contact between nursing staff and patients is crucial, since this contact significantly associated with negative daydreaming, probably due to increased neediness of emotional and physical care in some patients. The duration of the isolation has an influence on the experience of anxiety. Activities to cope with the isolation, however, not always have positive effects on the well-being of the patient.

SELECTION OF CITATIONS
SEARCH DETAIL
...