Background:In view of the ever-increasing representation of Staphylococcus spp.strains resistant to various antibiotics,the development of in vivo models for evaluation of novel antimicrobials is of utmost importance....Background:In view of the ever-increasing representation of Staphylococcus spp.strains resistant to various antibiotics,the development of in vivo models for evaluation of novel antimicrobials is of utmost importance.Methods:In this article,we describe the development of a fully immunocompetent porcine model of extensive skin and soft tissue damage suitable for testing topical anti-microbial agents that matches the real clinical situation.The model was developed in three consecutive stages with protocols for each stage amended based on the results of the previous one.Results:In the final model,10 excisions of the skin and underlying soft tissue were created in each pig under general anesthesia,with additional incisions to the fascia performed at the base of the defects and immediately inoculated with Staphylococcus aureus suspension.One pig was not inoculated and used as the negative control.Subsequently,the bandages were changed on Days 4,8,11,and 15.At these time points,a filter paper imprint technique(FPIT)was made from each wound for semi-quantitative microbiological evaluation.Tissue samples from the base of the wound together with the adjacent intact tissue of three randomly selected defects of each pig were taken for microbiological,histopathological,and molecular-biological examination.The infection with the inoculated S.aureus strains was sufficient during the whole experiment as confirmed by both FPIT and from tissue samples.The dynamics of the inflammatory markers and clinical signs of infection are also described.Conclusions:A successfully developed porcine model is suitable for in vivo testing of novel short-acting topical antimicrobial agents.展开更多
Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insig...Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.展开更多
Nowadays with the improvement in the degree of emphasis on new energy, the wind power system has developed more and more rapidly over the world. Usually the wind plants are located in the remote areas which are far fr...Nowadays with the improvement in the degree of emphasis on new energy, the wind power system has developed more and more rapidly over the world. Usually the wind plants are located in the remote areas which are far from the load centers. Generally series compensated AC transmission and high voltage DC transmission are made use of to improve the transmission capacity as two main effective ways which can solve the problem of large scale wind power transmission. The paper describes the three kinds of impact varieties and impact mechanisms in the sub-synchronous oscillation phenomena of wind power system based on doubly fed induction generator (DFIG) wind generators. At last, we point out the important problem that should be stressed in the wind power system.展开更多
This paper performs a study on three-way subsynchronous torsional interactions(SSTI)between a hybrid dual-infeed high-voltage direct current(HVDC)system and a nuclear generator.The test case is based on the French IFA...This paper performs a study on three-way subsynchronous torsional interactions(SSTI)between a hybrid dual-infeed high-voltage direct current(HVDC)system and a nuclear generator.The test case is based on the French IFA2000 line commutated converter(LCC)HVDC(2 GW)and the new Eleclink modular multilevel converter(MMC)HVDC(1 GW)interacting with the Gravelines generator(1 GW).The analysis is performed by the means of the eigenvalue stability assessment on an analytical model,while the accuracy of the conclusions is verified using the detailed non-linear electromegnetic transient program(EMTP)model.The study shows that the dual-infeed system may introduce higher risk of the SSTI compared with the point-to-point HVDC systems.It shows that MMC operating as static synchronous compensator(STATCOM)may further reduce the torsional damping at 6.3 Hz mode.This conclusion may be unexpected since it is known fact from literature that STATCOM has a beneficial impact on the transient performance of LCC.Further studies show that in a sequential HVDC loading,it may be beneficial to load the MMC HVDC first.Also,the risk of the SSTI may be minimized by changing HVDC controller gains,in particular,by increasing phaselocked-loop(PLL)gains on the LCC rectifier.展开更多
基金Supported by the Ministry of Health of the Czech Republic,Grant/Award Number:NU22-05-00475 and NV19-05-00214。
文摘Background:In view of the ever-increasing representation of Staphylococcus spp.strains resistant to various antibiotics,the development of in vivo models for evaluation of novel antimicrobials is of utmost importance.Methods:In this article,we describe the development of a fully immunocompetent porcine model of extensive skin and soft tissue damage suitable for testing topical anti-microbial agents that matches the real clinical situation.The model was developed in three consecutive stages with protocols for each stage amended based on the results of the previous one.Results:In the final model,10 excisions of the skin and underlying soft tissue were created in each pig under general anesthesia,with additional incisions to the fascia performed at the base of the defects and immediately inoculated with Staphylococcus aureus suspension.One pig was not inoculated and used as the negative control.Subsequently,the bandages were changed on Days 4,8,11,and 15.At these time points,a filter paper imprint technique(FPIT)was made from each wound for semi-quantitative microbiological evaluation.Tissue samples from the base of the wound together with the adjacent intact tissue of three randomly selected defects of each pig were taken for microbiological,histopathological,and molecular-biological examination.The infection with the inoculated S.aureus strains was sufficient during the whole experiment as confirmed by both FPIT and from tissue samples.The dynamics of the inflammatory markers and clinical signs of infection are also described.Conclusions:A successfully developed porcine model is suitable for in vivo testing of novel short-acting topical antimicrobial agents.
文摘Introduction: Bacterial skin and soft tissue infections (SSTIs) are a cause of frequent inpatient and outpatient care visits whose causative agents are associated with a high antimicrobial resistance burden. For insights on antimicrobial susceptibilities in a rural setting, we examined specimens from suspected SSTIs from two public health facilities in Kenya. We additionally assessed antibiotic use, appropriateness of empiric therapy and risk factors for SSTI. Methodology: Between 2021 and 2023, 265 patients at Kisii and Nyamira County Referral hospitals were enrolled. Wound swabs/aspirates were collected and processed following standard microbiological procedures. Identification and antimicrobial susceptibility were performed using the VITEK 2 Compact platform. Demographic, clinical, and microbiological data were analyzed with R Statistical software. Results: S. aureus was isolated in 16.2% (43/265) of patients with a methicillin resistance (MRSA) proportion of 14% (6/43). While 13/15 drugs elicited susceptibilities ranging from 84% - 100%, penicillin (16%) and trimethoprim-sulfamethoxazole [TMP-SXT] (23%) yielded the lowest susceptibilities. Escherichia coli (n = 33), Klebsiella pneumoniae (n = 8), Pseudomonas aeruginosa (n = 8), and Citrobacter species (n = 4) were the most commonly isolated gram-negative species. Gram-negative strains showed high susceptibilities to most of the tested drugs (71% - 100%) with the exception of ampicillin (18%), TMP-SXT (33%), and first and second generation cephalosporins. Conclusions: The low MRSA prevalence and generally high antibiotic susceptibilities for S. aureus and gram-negative bacteria present opportunities for antibiotic stewardship in the study setting. Diminished susceptibilities against penicillin/ampicillin and TMP-SXT accord with prevailing local data and add a layer of evidence for their cautious empiric use.
文摘Nowadays with the improvement in the degree of emphasis on new energy, the wind power system has developed more and more rapidly over the world. Usually the wind plants are located in the remote areas which are far from the load centers. Generally series compensated AC transmission and high voltage DC transmission are made use of to improve the transmission capacity as two main effective ways which can solve the problem of large scale wind power transmission. The paper describes the three kinds of impact varieties and impact mechanisms in the sub-synchronous oscillation phenomena of wind power system based on doubly fed induction generator (DFIG) wind generators. At last, we point out the important problem that should be stressed in the wind power system.
基金supported by Réseau de Transport d’électricitéof France。
文摘This paper performs a study on three-way subsynchronous torsional interactions(SSTI)between a hybrid dual-infeed high-voltage direct current(HVDC)system and a nuclear generator.The test case is based on the French IFA2000 line commutated converter(LCC)HVDC(2 GW)and the new Eleclink modular multilevel converter(MMC)HVDC(1 GW)interacting with the Gravelines generator(1 GW).The analysis is performed by the means of the eigenvalue stability assessment on an analytical model,while the accuracy of the conclusions is verified using the detailed non-linear electromegnetic transient program(EMTP)model.The study shows that the dual-infeed system may introduce higher risk of the SSTI compared with the point-to-point HVDC systems.It shows that MMC operating as static synchronous compensator(STATCOM)may further reduce the torsional damping at 6.3 Hz mode.This conclusion may be unexpected since it is known fact from literature that STATCOM has a beneficial impact on the transient performance of LCC.Further studies show that in a sequential HVDC loading,it may be beneficial to load the MMC HVDC first.Also,the risk of the SSTI may be minimized by changing HVDC controller gains,in particular,by increasing phaselocked-loop(PLL)gains on the LCC rectifier.
