scholarly journals The bactericidal effect of continuous wave laser with strongly absorbing coating at the fiber tip

2018 ◽  
Vol 11 (05) ◽  
pp. 1850029
Author(s):  
Vadim Elagin ◽  
Anton Smirnov ◽  
Vladimir Yusupov ◽  
Alexey Kirillov ◽  
Nadezhda Ignatova ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Large Scale ◽  
Near Infrared ◽  
Continuous Wave ◽  
Bacterial Species ◽  
Bactericidal Effect ◽  
Bacterial Suspension ◽  
Main Role ◽  
Continuous Wave Laser ◽  
E Coli

The bactericidal effect of laser radiation with a quartz fiber-based transmission system with a strong absorption coating converter against bacteria associated with urological stones has been studied. Gram-negative rod Escherichia coli and the Gram-positive coccus Staphylococcus epidermidis, Staphylococcus aureus, Enterococcus faecalis and Enterococcus faecium were used in this study. Each bacterial species was treated by continuous-wave near infrared laser coupled with bare fiber tip or strongly absorption coating fiber tip. After treatment, the temperature of bacterial suspension was measured. In addition, the temperature distribution was analyzed. It has been shown that using laser with a strongly absorption coating fiber tip results in significant bactericidal effect. The decrease of the amount of E. coli and S. epidermidis was 100% after treatment with an output power of 6[Formula: see text]W of radiation at a wavelength of 0.97[Formula: see text][Formula: see text]m for 40[Formula: see text]s. Number of S. aureus and Ent. faecium colony-forming unit was reduced to 70% after same exposure. The peak temperature of bacterial suspension was [Formula: see text]C after treatment by laser with a strongly absorption coating fiber tip. Laser with a strongly absorption coating fiber tip provides large-scale hydrodynamic flows directed away from the fiber tip. The laser with a strongly absorption coating fiber tip has bactericidal effect. The main role is associated with the effect of high temperature, which, in the form of flow in a liquid medium, affects bacteria.

scholarly journals THE RATE OF BACTERICIDAL ACTION OF PENICILLIN IN VITRO AS A FUNCTION OF ITS CONCENTRATION, AND ITS PARADOXICALLY REDUCED ACTIVITY AT HIGH CONCENTRATIONS AGAINST CERTAIN ORGANISMS

1948 ◽  
Vol 88 (1) ◽  
pp. 99-131 ◽  
Author(s):  
Harry Eagle ◽  
A. D. Musselman
Keyword(s):  
Bacterial Species ◽  
Fold Increase ◽  
Bactericidal Effect ◽  
Penicillin G ◽  
Bacterial Suspension ◽  
Maximal Effect ◽  
Maximal Rate ◽  
Effective Level ◽  
High Concentrations

1. The concentrations of penicillin G which (a) reduced the net rate of multiplication, (b) exerted a net bactericidal effect, and (c) killed the organisms at a maximal rate, have been defined for a total of 41 strains of α- and ß-hemolytic streptococci, Staphylococcus aureus and Staphylococcus albus, Diplococcus pneumoniae, and the Reiter treponoma. 2. The concentration which killed the organisms at a maximal rate was 2 to 20 times the minimal effective level ("sensitivity" as ordinarily defined). With some organisms, even a 32,000-fold increase beyond this maximally effective level did not further increase the rate of its bactericidal effect. However, with approximately half the strains here studied (all 4 strains of group B ß-hemolytic streptococci, 4 of 5 group C strains, 5 of 7 strains of Streptococcus fecalis, 2 of 4 other α-hemolytic streptococci, and 4 of 9 strains of staphylococci), when the concentration of penicillin was increased beyond that optimal level, the rate at which the organisms died was paradoxically reduced rather than increased, so that the maximal effect was obtained only within a relatively narrow optimal zone. 3. There were marked differences between bacterial species, and occasionally between different strains of the same species, not only with respect to the effective concentrations of penicillin, but also with respect to the maximal rate at which they could be killed by the drug in any concentration. Although there was a rough correlation between these two factors, there were many exceptions; individual strains affected only by high concentrations of penicillin might nevertheless be killed rapidly, while strains sensitive to minute concentrations might be killed only slowly. 4. Within the same bacterial suspension, individual organisms varied only to a minor degree with respect to the effective concentrations of penicillin. They varied strikingly, however, in their resistance to penicillin as measured by the times required to kill varying proportions of the cells.

scholarly journals Near-Infrared Spectroscopy Evaluations for the Differentiation of Carbapenem-Resistant from Susceptible Enterobacteriaceae Strains

Diagnostics ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 736
Author(s):  
Bushra Alharbi ◽  
Maggy Sikulu-Lord ◽  
Anton Lord ◽  
Hosam M. Zowawi ◽  
Ella Trembizki
Keyword(s):  
Infrared Spectroscopy ◽  
Near Infrared Spectroscopy ◽  
Near Infrared ◽  
Predictive Accuracy ◽  
Bacterial Species ◽  
Carbapenem Resistance ◽  
Accurate Identification ◽  
E Coli ◽  
Carbapenem Resistant ◽  
Global Threat

Antimicrobial Resistance (AMR) caused by Carbapenem-Resistant Enterobacteriaceae (CRE) is a global threat. Accurate identification of these bacterial species with associated AMR is critical for their management. While highly accurate methods to detect CRE are available, they are costly, timely and require expert skills, making their application infeasible in low-resource settings. Here, we investigated the potential of Near-Infrared Spectroscopy (NIRS) for a range of applications: (i) the detection and differentiation of isolates of two pathogenic Enterobacteriaceae species, Klebsiella pneumoniae and Escherichia coli, and (ii) the differentiation of carbapenem resistant and susceptible K. pneumoniae. NIRS has successfully differentiated between K. pneumoniae and E. coli isolates with a predictive accuracy of 89.04% (95% CI; 88.7–89.4%). K. pneumoniae isolates harbouring carbapenem-resistance determinants were differentiated from susceptible K. pneumoniae strains with an accuracy of 85% (95% CI; 84.2–86.1%). To our knowledge, this is the largest proof of concept demonstration for the utility and feasibility of NIRS to rapidly differentiate between K. pneumoniae and E. coli as well as carbapenem-resistant K. pneumoniae from susceptible strains.

scholarly journals Recent Advances in the Surface Functionalization of Nanomaterials for Antimicrobial Applications

Materials ◽  
2021 ◽  
Vol 14 (22) ◽  
pp. 6932
Author(s):  
Shahin Shah Khan ◽  
Irfan Ullah ◽  
Sadeeq Ullah ◽  
Ruipeng An ◽  
Haijun Xu ◽  
...  
Keyword(s):  
Surface Functionalization ◽  
Near Infrared ◽  
Biomedical Application ◽  
Bacterial Species ◽  
Multidrug Resistant ◽  
Pathogenic Microorganisms ◽  
Infrared Irradiation ◽  
Oxygen Production ◽  
E Coli ◽  
High Absorption

Innovations in nanotechnology have had an immense impact on medicine, such as in drug delivery, tissue engineering, and medical devices that combat different pathogens. The pathogens that may cause biofilm-associated nosocomial diseases are multidrug-resistant (MDR) bacteria, such as Escherichia coli (E. coli), Pseudomonas aeruginosa (P. aeruginosa), Staphylococcus aureus (S. aureus), including both Gram-positive and Gram-negative bacterial species. About 65–80% of infections are caused by biofilm-associated pathogens creating a move in the international community toward developing antimicrobial therapies to eliminate such pathogenic infections. Several nanomaterials (NMs) have been discovered and significantly employed in various antipathogenic therapies. These NMs have unique properties of singlet oxygen production, high absorption of near-infrared irradiation, and reasonable conversion of light to heat. In this review, functionalized NPs that combat different pathogenic infections are introduced. This review highlights NMs that combat infections caused by multidrug-resistant (MDR) and other pathogenic microorganisms. It also highlights the biomedical application of NPs with regard to antipathogenic activities.

Manipulation of dual fluorescence behavior in aggregation-induced emission enhancement of a tetraphenylethene-appended polymer by optical tweezers

2021 ◽  
Author(s):  
Shun-Fa Wang ◽  
Bo-Wei Chen ◽  
Ayami Itagaki ◽  
Fumitaka Ishiwari ◽  
Takanori Fukushima ◽  
...  
Keyword(s):  
Optical Tweezers ◽  
Near Infrared ◽  
Continuous Wave ◽  
Continuous Wave Laser ◽  
Dual Fluorescence ◽  
Aggregation Induced Emission ◽  
Emission Enhancement ◽  
Wave Laser

The manipulation of dual fluorescence behavior in aggregation-induced emission enhancement (AIEE) of a tetraphenylethene (TPE)-appended polymer by optical tweezers was investigated herein. Optical tweezers using a focused near-infrared continuous-wave laser...

scholarly journals Opto-thermophoretic separation and trapping of plasmonic nanoparticles

Nanoscale ◽  
2019 ◽  
Vol 11 (44) ◽  
pp. 21093-21102 ◽  
Author(s):  
Kenji Setoura ◽  
Tetsuro Tsuji ◽  
Syoji Ito ◽  
Satoyuki Kawano ◽  
Hiroshi Miyasaka
Keyword(s):  
Near Infrared ◽  
Continuous Wave ◽  
Colloidal Suspension ◽  
Gold Nanoshells ◽  
Plasmonic Nanoparticles ◽  
Continuous Wave Laser ◽  
Wave Laser

We have succeeded in the selective trapping of single gold nanoshells with specific sizes and sweeping others out completely, only by irradiating the dense colloidal suspension of gold nanoshells with a focused near infrared continuous-wave laser.

Influence of Ethanol With and Without Chlorhexidine on the Bacterial Colonization of the Umbilicus of Newborn Infants

1984 ◽  
Vol 5 (6) ◽  
pp. 275-278 ◽  
Author(s):  
S. Bygdeman ◽  
A Hambraeus ◽  
A. Henningsson ◽  
B. Nyström ◽  
C. Skoglund ◽  
...  
Keyword(s):  
Staphylococcus Epidermidis ◽  
Bacterial Colonization ◽  
Bacterial Species ◽  
Newborn Infants ◽  
The Other ◽  
E Coli ◽  
Ethanol Group ◽  
Group G Streptococci ◽  
The One ◽  
Group B

AbstractThe effect of daily treatments with 70% ethanol and with 0.5% Chlorhexidine in 70% ethanol, respectively, on navel colonization in newborns has been studied in 624 infants in two maternity wards during a four-month period. Staphylococcus aureus, group B and G streptococci, E. coli and anaerobes were significantly less often isolated from newborns whose umbilical cord was treated with Chlorhexidine in ethanol than from those treated with ethanol only. Staphylococcus epidermidis and enterococci, on the other hand, were significantly more often isolated from the chlorhexidine-ethanol than from the ethanol group. More infants without colonization of the umbilicus on their fourth day of life were found in the Chlorhexidine in ethanol than in the ethanol group. The infants in the ethanol group were colonized with significantly more bacterial species than the infants in the other group. Signs of dissemination of group B and group G streptococci between babies were seen more often in the group of infants treated with ethanol than in the one treated with chlorhexidine-ethanol.

scholarly journals What can we learn from over 100,000 Escherichia coli genomes?

2019 ◽  
Author(s):  
Kaleb Abram ◽  
Zulema Udaondo ◽  
Carissa Bleker ◽  
Visanu Wanchai ◽  
Trudy M. Wassenaar ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Large Scale ◽  
Phylogenetic Analyses ◽  
Bacterial Species ◽  
Single Copy ◽  
Gene Gain ◽  
E Coli ◽  
Phylogenetic Profiles ◽  
Genomic Studies ◽  
Gain Loss

ABSTRACTThe explosion of microbial genome sequences in public databases allows for large-scale population genomic studies of bacterial species, such as Escherichia coli. In this study, we examine and classify more than one hundred thousand E. coli and Shigella genomes. After removing outliers, a semi-automated Mash-based analysis of 10,667 assembled genomes reveals 14 distinct phylogroups. A representative genome or medoid identified for each phylogroup serves as a proxy to classify more than 95,000 unassembled genomes. This analysis shows that most sequenced E. coli genomes belong to 4 phylogroups (A, C, B1 and E2(O157)). Authenticity of the 14 phylogroups described is supported by pangenomic and phylogenetic analyses, which show differences in gene preservation between phylogroups. A phylogenetic tree constructed with 2,613 single copy core genes along with a matrix of phylogenetic profiles is used to confirm that the 14 phylogroups change at different rates of gene gain/loss/duplication. The methodology used in this work is able to identify previously uncharacterized phylogroups in E. coli species. Some of these new phylogroups harbor clonal strains that have undergone a process of genomic adaptation to the acquisition of new genomic elements related to virulence or antibiotic resistance. This is, to our knowledge, the largest E. coli genome dataset analyzed to date and provides valuable insights into the population structure of the species.

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