scholarly journals Inactivation of Spores and Vegetative Forms of Clostridioides Difficile by Chemical Biocides: Mechanisms of Biocidal Activity, Methods of Evaluation, and Environmental Aspects

2022 ◽  
Vol 19 (2) ◽  
pp. 750
Author(s):  
Weronika Augustyn ◽  
Arkadiusz Chruściel ◽  
Wiesław Hreczuch ◽  
Joanna Kalka ◽  
Patryk Tarka ◽  
...  
Keyword(s):  
Bacterial Biofilm ◽  
Experimental Methodology ◽  
Effective Control ◽  
Attractive Alternative ◽  
Biochemical Basis ◽  
Clostridioides Difficile ◽  
Action Mechanisms ◽  
Methods Of Evaluation ◽  
Disinfection Procedure ◽  
Clinical Conditions

Clostridioides difficile infections (CDIs) are the most common cause of acquired diseases in hospitalized patients. Effective surface disinfection, focused on the inactivation of the spores of this pathogen, is a decisive factor in reducing the number of nosocomial cases of CDI infections. An efficient disinfection procedure is the result of both the properties of the biocidal agent used and the technology of its implementation as well as a reliable, experimental methodology for assessing the activity of the biocidal active substance based on laboratory models that adequately represent real clinical conditions. This study reviews the state of knowledge regarding the properties and biochemical basis of the action mechanisms of sporicidal substances, with emphasis on chlorine dioxide (ClO2). Among the analyzed biocides, in addition to ClO2, active chlorine, hydrogen peroxide, peracetic acid, and glutaraldehyde were characterized. Due to the relatively high sporicidal effectiveness and effective control of bacterial biofilm, as well as safety in a health and environmental context, the use of ClO2 is an attractive alternative in the control of nosocomial infections of CD etiology. In terms of the methods of assessing the biocidal effectiveness, suspension and carrier standards are discussed.

scholarly journals Polymerase Chain Reaction (PCR) as a Potential Point of Care Laboratory Test for Leprosy Diagnosis—A Systematic Review

2018 ◽  
Vol 3 (4) ◽  
pp. 107 ◽  
Author(s):  
Sushma Tatipally ◽  
Aparna Srikantam ◽  
Sanjay Kasetty
Keyword(s):  
Systematic Review ◽  
Polymerase Chain Reaction ◽  
Point Of Care ◽  
Effective Control ◽  
Chain Reaction ◽  
Review Analysis ◽  
Pubmed Database ◽  
Early Case ◽  
Polymerase Chain ◽  
Clinical Conditions

Leprosy is an infectious disease caused by Mycobacterium leprae and mainly affects skin, peripheral nerves, and eyes. Suitable tools for providing bacteriological evidence of leprosy are needed for early case detection and appropriate therapeutic management. Ideally these tools are applicable at all health care levels for the effective control of leprosy. This paper presents a systematic review analysis in order to investigate the performance of polymerase chain reaction (PCR) vis-à-vis slit skin smears (SSS) in various clinical settings and its potential usefulness as a routine lab test for leprosy diagnosis. Records of published journal articles were identified through PubMed database search. Twenty-seven articles were included for the analysis. The evidence from this review analysis suggests that PCR on skin biopsy is the ideal diagnostic test. Nevertheless, PCR on SSS samples also seems to be useful with its practical value for application, even at primary care levels. The review findings also indicated the necessity for improving the sensitivity of PCR and further research on specificity in ruling out other clinical conditions that may mimic leprosy. The M. leprae-specific repetitive element (RLEP) was the most frequently-used marker although its variable performance across the clinical sites and samples are a matter of concern. Undertaking further research studies with large sample numbers and uniform protocols studied simultaneously across multiple clinical sites is recommended to address these issues.

scholarly journals Probabilistic transmission models incorporating sequencing data for healthcare-associated Clostridioides difficile outperform heuristic rules and identify strain-specific differences in transmission

2021 ◽  
Vol 17 (1) ◽  
pp. e1008417
Author(s):  
David W. Eyre ◽  
Mirjam Laager ◽  
A. Sarah Walker ◽  
Ben S. Cooper ◽  
Daniel J. Wilson ◽  
...  
Keyword(s):  
Environmental Contamination ◽  
Large Scale ◽  
Epidemiological Data ◽  
Effective Control ◽  
Healthcare Associated Infections ◽  
Sequencing Data ◽  
Medical Specialties ◽  
Clostridioides Difficile ◽  
Healthcare Associated ◽  
Transmission Models

Fitting stochastic transmission models to electronic patient data can offer detailed insights into the transmission of healthcare-associated infections and improve infection control. Pathogen whole-genome sequencing may improve the precision of model inferences, but computational constraints have limited modelling applications predominantly to small datasets and specific outbreaks, whereas large-scale sequencing studies have mostly relied on simple rules for identifying/excluding plausible transmission. We present a novel approach for integrating detailed epidemiological data on patient contact networks in hospitals with large-scale pathogen sequencing data. We apply our approach to study Clostridioides difficile transmission using a dataset of 1223 infections in Oxfordshire, UK, 2007–2011. 262 (21% [95% credibility interval 20–22%]) infections were estimated to have been acquired from another known case. There was heterogeneity by sequence type (ST) in the proportion of cases acquired from another case with the highest rates in ST1 (ribotype-027), ST42 (ribotype-106) and ST3 (ribotype-001). These same STs also had higher rates of transmission mediated via environmental contamination/spores persisting after patient discharge/recovery; for ST1 these persisted longer than for most other STs except ST3 and ST42. We also identified variation in transmission between hospitals, medical specialties and over time; by 2011 nearly all transmission from known cases had ceased in our hospitals. Our findings support previous work suggesting only a minority of C. difficile infections are acquired from known cases but highlight a greater role for environmental contamination than previously thought. Our approach is applicable to other healthcare-associated infections. Our findings have important implications for effective control of C. difficile.

scholarly journals Immobilizing hydrolytic active Papain on biodegradable PLLA for biofilm inhibition in cardiovascular applications

2020 ◽  
Vol 6 (3) ◽  
pp. 172-175
Author(s):  
Michael Teske ◽  
Tina Kießlich ◽  
Niels Grabow ◽  
Sabine Illner ◽  
Julia Fischer ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Antimicrobial Agents ◽  
Hydrolytic Enzyme ◽  
Bacterial Biofilm ◽  
Biofilm Inhibition ◽  
Biofilm Growth ◽  
Clostridioides Difficile ◽  
Adhesive Surface

AbstractThe use of biomaterials in medicine is becoming increasingly important. One of the main concerns is the foreign body associated infection caused by direct microbial contamination or clinical infections. The bacterial biofilm formation on biomaterials depends on their surface properties. Therefore, several anti-adhesive surface modifications were developed. Nevertheless, the demand for antimicrobial agents that prevent bacterial colonisation is still largely unmet. The immobilization of active antimicrobial agents, such as antibacterial peptides or enzymes, offers a potential approach to achieve long-lasting effectiveness. In this investigation, the hydrolytic enzyme papain with its published antibacterial activity was covalently immobilized on the well-established biodegradable biomaterial poly-L-lactic acid (PLLA). For the characterization of the enzymes on the PLLA surfaces, the protein content and enzyme activity were determined. A biofilm assay was performed to test the effect of the papain-modified PLLA samples on the biofilm-forming bacterial strain Clostridioides difficile, one of the most frequently occurring human nosocomial pathogens. The investigated hydrolytic enzyme papain could be immobilized by coupling via the crosslinker EDC to the PLLA surface. Detection was performed by determination of the amount of protein and the reduced biofilm growth after 24 h and 72 h compared to the reference.

Characterization of Bacteriophages Targeting Non-O157 Shiga Toxigenic Escherichia coli

2018 ◽  
Vol 81 (5) ◽  
pp. 785-794 ◽  
Author(s):  
PUSHPINDER KAUR LITT ◽  
JOYJIT SAHA ◽  
DIVYA JARONI
Keyword(s):  
Escherichia Coli ◽  
Latent Period ◽  
Foodborne Pathogens ◽  
Food Industry ◽  
Control Strategies ◽  
Burst Size ◽  
Effective Control ◽  
Attractive Alternative ◽  
C Storage

ABSTRACT Non-O157 Shiga toxigenic Escherichia coli (STEC) are an important group of foodborne pathogens, implicated in several outbreaks and recalls in the past 2 decades. It is therefore crucial to devise effective control strategies against these pathogens. Bacteriophages present an attractive alternative to conventional pathogen control methods in the food industry. Bacteriophages, targeting non-O157 STEC (O26, O45, O103, O111, O121, O145), were isolated from beef cattle operations in Oklahoma. Their host range and lytic ability were determined against several (n = 21) non-O157 STEC isolates, by using the spot-on-lawn assay. Isolated phages were purified, and their morphology was determined under a transmission electron microscope. Infection kinetics of selected phages (n = 19), particularly adsorption rate, rise period, latent period, and burst size, were determined. Phages were also evaluated for stability at a wide pH range (1 to 11) and temperature range (−80 to 90°C). In total, 45 phages were isolated and classified into Myoviridae, Siphoviridae, or Tectiviridae. The phages had a latent period between 8 and 37 min, a rise period between 19 and 40 min, and a large burst size (12 to 794 virions per infected cell), indicating high lytic activity. Tested phages were stable at pH 5 to 9 for 24 h, whereas a decrease in phage titer was observed at pHs 1, 2, and 11. Phages were stable at 40 and 60°C, except for O103-specific phages. At 70°C, all the phages lost viability after 20 min, except three phages targeting O26 and O121 and one phage targeting O45 and O111 STEC, which remained viable for 60 min. All the phages lost activity after 10 min at 90°C, except one each of O26 and O121 STEC–infecting phages that remained viable for 60 min. Phages remained stable for 90 days under refrigerated (4°C) and frozen (−20 and −80°C) storage. Characterization of phages, targeting diverse non-O157 STEC serotypes, could help in the development of effective biocontrol strategies for this group of pathogens in the food industry.

scholarly journals Opportunities for Nanomedicine in Clostridioides difficile Infection

Antibiotics ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 948
Author(s):  
Pei-Wen Wang ◽  
Wei-Ting Lee ◽  
Ya-Na Wu ◽  
Dar-Bin Shieh
Keyword(s):  
Harsh Environments ◽  
Effective Control ◽  
Potential Contribution ◽  
Complex Structures ◽  
Effective Management ◽  
Vegetative Cells ◽  
Clostridioides Difficile ◽  
Clostridioides Difficile Infection ◽  
Infectious Pathogen ◽  
Suitable Environment

Clostridioides difficile, a spore-forming bacterium, is a nosocomial infectious pathogen which can be found in animals as well. Although various antibiotics and disinfectants were developed, C. difficile infection (CDI) remains a serious health problem. C. difficile spores have complex structures and dormant characteristics that contribute to their resistance to harsh environments, successful transmission and recurrence. C. difficile spores can germinate quickly after being exposed to bile acid and co-germinant in a suitable environment. The vegetative cells produce endospores, and the mature spores are released from the hosts for dissemination of the pathogen. Therefore, concurrent elimination of C. difficile vegetative cells and inhibition of spore germination is essential for effective control of CDI. This review focused on the molecular pathogenesis of CDI and new trends in targeting both spores and vegetative cells of this pathogen, as well as the potential contribution of nanotechnologies for the effective management of CDI.

The Critical Point Drying Method Applied to Scanning Electron Microscopy of L-929 Cells

1970 ◽  
Vol 28 ◽  
pp. 278-279
Author(s):  
Charles TurnbiLL ◽  
Delbert E. Philpott
Keyword(s):  
Electron Microscopy ◽  
Carbon Dioxide ◽  
Surface Tension ◽  
Critical Point ◽  
Freeze Drying ◽  
Attractive Alternative ◽  
Crystal Formation ◽  
Critical Point Drying ◽  
Time Required ◽  
Scanning Electron

The advent of the scanning electron microscope (SCEM) has renewed interest in preparing specimens by avoiding the forces of surface tension. The present method of freeze drying by Boyde and Barger (1969) and Small and Marszalek (1969) does prevent surface tension but ice crystal formation and time required for pumping out the specimen to dryness has discouraged us. We believe an attractive alternative to freeze drying is the critical point method originated by Anderson (1951; for electron microscopy. He avoided surface tension effects during drying by first exchanging the specimen water with alcohol, amy L acetate and then with carbon dioxide. He then selected a specific temperature (36.5°C) and pressure (72 Atm.) at which carbon dioxide would pass from the liquid to the gaseous phase without the effect of surface tension This combination of temperature and, pressure is known as the "critical point" of the Liquid.

Studies on the Fungal Pathogen of Dutch Elm Disease

1981 ◽  
Vol 39 ◽  
pp. 400-401
Author(s):  
H.M. Mazzone ◽  
G. Wray ◽  
R. Zerillo
Keyword(s):  
Fungal Pathogen ◽  
Fungal Growth ◽  
Polymyxin B ◽  
The United States ◽  
Dutch Elm Disease ◽  
Effective Control ◽  
Sabouraud Agar ◽  
Total Inhibition ◽  
Zones Of Inhibition ◽  
Control Plate

The fungal pathogen of the Dutch elm disease (DED), Ceratocystis ulmi (Buisman) C. Moreau, has eluded effective control since its introduction in the United States more than sixty years ago. Our studies on DED include establishing biological control agents against C. ulmi. In this report we describe the inhibitory action of the antibiotic polymyxin B on the causal agent of DED.In screening a number of antibiotics against C. ulmi, we observed that filter paper discs containing 300 units (U) of polymyxin B (Difco Laboratories) per disc, produced zones of inhibition to the fungus grown on potato dextrose agar or Sabouraud agar plates (100mm x 15mm), Fig. 1a. Total inhibition of fungal growth on a plate occurred when agar overlays containing fungus and antibiotic (polymyxin B sulfate, ICN Pharmaceuticals, Inc.) were poured on the underlying agar growth medium. The agar overlays consisted of the following: 4.5 ml of 0.7% agar, 0.5 ml of fungus (control plate); 4.0 ml of 0.7% agar, 0.5 ml of fungus, 0.5 ml of polymyxin B sulfate (77,700 U). Fig. 1, b and c, compares a control plate and polymyxin plate after seven days.

Bacterial biofilm behavior in water-supply lines of dental units

1992 ◽  
Vol 50 (1) ◽  
pp. 882-883
Author(s):  
B.D. Tall ◽  
K.S. George ◽  
R. T. Gray ◽  
H.N. Williams
Keyword(s):  
Water Supply ◽  
Medical Devices ◽  
Biofilm Formation ◽  
Bacterial Biofilm

Studies of bacterial behavior in many environments have shown that most organisms attach to surfaces, forming communities of microcolonies called biofilms. In contaminated medical devices, biofilms may serve both as reservoirs and as inocula for the initiation of infections. Recently, there has been much concern about the potential of dental units to transmit infections. Because the mechanisms of biofilm formation are ill-defined, we investigated the behavior and formation of a biofilm associated with tubing leading to the water syringe of a dental unit over a period of 1 month.

Design of a Field-Emission Gun for the Phillips CM20/STEM microscope

1990 ◽  
Vol 48 (2) ◽  
pp. 100-101
Author(s):  
P.M. Mul ◽  
B.J.M. Bormans ◽  
L. Schaap
Keyword(s):  
High Resolution ◽  
Field Emission ◽  
Analytical Electron Microscopy ◽  
Emission Region ◽  
Attractive Alternative ◽  
Electron Holography ◽  
Field Emitter ◽  
Field Emitters ◽  
Resolution Electron ◽  
High Resolution Tem

The first Field Emission Guns (FEG) on TEM/STEM instruments were introduced by Philips in 1977. In the past decade these EM400-series microscopes have been very successful, especially in analytical electron microscopy, where the high currents in small probes are particularly suitable. In High Resolution Electron Holography, the high coherence of the FEG has made it possible to approach atomic resolution.Most of these TEM/STEM systems are based on a cold field emitter (CFE). There are, however, a number of disadvantages to CFE’s, because of their very small emission region: the maximum current is limited (a strong disadvantage for high-resolution TEM imaging) and the emission is unstable, requiring special measures to reduce the strong FEG-induced noise. Thermal field emitters (TFE), i.e. a zirconiated field emitter source operating in the thermal or Schottky mode, have been shown to be a viable and attractive alternative to CFE’s. TFE’s have larger emission regions, providing much higher maximum currents, better stability, and reduced sensitivity to vacuum conditions as well as mechanical and electrical interferences.

Ultrastructural analysis of “Sensory” surface nerve endings and “putative” neurotransmitter sites in Schistosoma mansoni Miracidia

1989 ◽  
Vol 47 ◽  
pp. 962-963
Author(s):  
Betty Ruth Jones ◽  
Steve Chi-Tang Pan
Keyword(s):  
Nervous System ◽  
Life Cycle ◽  
Schistosoma Mansoni ◽  
Snail Host ◽  
Complex Life Cycle ◽  
Rational Approach ◽  
Effective Control ◽  
The Social ◽  
Social And Economic Development ◽  
Basic Biology

INTRODUCTION: Schistosomiasis has been described as “one of the most devastating diseases of mankind, second only to malaria in its deleterious effects on the social and economic development of populations in many warm areas of the world.” The disease is worldwide and is probably spreading faster and becoming more intense than the overall research efforts designed to provide the basis for countering it. Moreover, there are indications that the development of water resources and the demands for increasing cultivation and food in developing countries may prevent adequate control of the disease and thus the number of infections are increasing.Our knowledge of the basic biology of the parasites causing the disease is far from adequate. Such knowledge is essential if we are to develop a rational approach to the effective control of human schistosomiasis. The miracidium is the first infective stage in the complex life cycle of schistosomes. The future of the entire life cycle depends on the capacity and ability of this organism to locate and enter a suitable snail host for further development, Little is known about the nervous system of the miracidium of Schistosoma mansoni and of other trematodes. Studies indicate that miracidia contain a well developed and complex nervous system that may aid the larvae in locating and entering a susceptible snail host (Wilson, 1970; Brooker, 1972; Chernin, 1974; Pan, 1980; Mehlhorn, 1988; and Jones, 1987-1988).

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