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9 pages, 923 KiB

Open AccessArticle

Parallel Colorimetric Quantification of Choline and Phosphocholine as a Method for Studying Choline Kinase Activity in Complex Mixtures

by Tahl Zimmerman and Salam A. Ibrahim

Antibiotics 2018, 7(1), 24; https://doi.org/10.3390/antibiotics7010024 - 17 Mar 2018

Cited by 8 | Viewed by 4725

Abstract

Choline kinase (Chok) is an enzyme found in eukaryotes and Gram-positive bacteria. Chok catalyzes the production of phosphocholine from choline and ATP. This enzyme has been validated as a drug target in Streptococcus pneumonia, but the role Chok enzymatic activity plays in [...] Read more.

Choline kinase (Chok) is an enzyme found in eukaryotes and Gram-positive bacteria. Chok catalyzes the production of phosphocholine from choline and ATP. This enzyme has been validated as a drug target in Streptococcus pneumonia, but the role Chok enzymatic activity plays in bacterial cell growth and division is not well understood. Phosphocholine production by Chok and its attenuation by inhibitors in the context of complex samples such as cell extracts can currently be quantified by several methods. These include choline depletion measurements, radioactive methods, mass-spectrometry, and nuclear magnetic resonance. The first does not measure phosphocholine directly, the second requires elaborate safety procedures, and the third and fourth require significant capital investments and technical expertise. For these reasons, a less expensive, higher throughput, more easily accessible assay is needed to facilitate further study in Gram-positive Choks. Here, we present the development of a triiodide/activated charcoal/molybdenum blue system for detecting and quantifying choline and phosphocholine in parallel. We demonstrate that this system can reliably quantify changes in choline and phosphocholine concentrations over time in Chok enzymatic assays using cell extracts as the source of the enzyme. This is an easily accessible, convenient, robust, and economical method for studying Chok activity in complex samples. The triiodide/activated charcoal/molybdenum blue system opens new doors into the study choline kinase in Gram-positive pathogens. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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7 pages, 410 KiB

Open AccessArticle

Survey of Nonprescription Medication and Antibiotic Use in Patients with Stevens-Johnson Syndrome, Toxic Epidermal Necrolysis, and Overlap Syndrome

by Katherine J. Sullivan, Meghan N. Jeffres, Robert P. Dellavalle, Robert Valuck and Heather D. Anderson

Antibiotics 2018, 7(1), 11; https://doi.org/10.3390/antibiotics7010011 - 01 Feb 2018

Cited by 3 | Viewed by 6484

Abstract

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and overlap syndrome (SJS-TEN) are rare, serious skin and mucosa break-down conditions frequently associated with antibiotic use. The role of nonprescription medications alone, or in combination with antibiotics in triggering SJS/TEN, is largely unknown. This study [...] Read more.

Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN), and overlap syndrome (SJS-TEN) are rare, serious skin and mucosa break-down conditions frequently associated with antibiotic use. The role of nonprescription medications alone, or in combination with antibiotics in triggering SJS/TEN, is largely unknown. This study summarized data collected from patient surveys about nonprescription and antibiotic use prior to a SJS/TEN diagnosis. The survey was administered online to members of the U.S. SJS Foundation who had been diagnosed with SJS/TEN or were the parent of a child who had been diagnosed with SJS/TEN. Respondents were asked about nonprescription medications taken within the year before diagnosis, and the approximate point in time before diagnosis that they had taken them. They were also asked about specific prescription medications, including antibiotics, that they took before diagnosis. An estimated 4500 patients received an invitation to complete the survey. 251 patients completed it, resulting in a response rate of 5.6%. The mean age of respondents was 43 years (SD (standard deviation) = 17.3) and 70% were female. 32.3% of respondents indicated that a prescription antibiotic triggered their reaction. 14.1% indicated a nonprescription medication had triggered their SJS/TEN, and 18.1% said a nonprescription medication may have triggered their SJS/TEN. 85.5% of respondents said they took a nonprescription medication within three months of their SJS/TEN diagnosis. Of those respondents who reported that an antibiotic triggered their SJS/TEN, 35.2% reported taking a nonprescription medication within the three months prior to their diagnosis. This survey captured valuable information about nonprescription and antibiotic use in SJS/TEN patients. It is important for future studies to estimate the impact of antibiotics on SJS/TEN, and account for nonprescription medication use in that relationship. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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8 pages, 225 KiB

Open AccessArticle

Assessing the Knowledge, Attitudes and Behaviors of Human and Animal Health Students towards Antibiotic Use and Resistance: A Pilot Cross-Sectional Study in the UK

by Oliver James Dyar, Holly Hills, Lara-Turiya Seitz, Alex Perry and Diane Ashiru-Oredope

Antibiotics 2018, 7(1), 10; https://doi.org/10.3390/antibiotics7010010 - 30 Jan 2018

Cited by 60 | Viewed by 10169

Abstract

The Global Action Plan on Antimicrobial Resistance highlights the importance of training all healthcare professionals. No study has assessed patterns of students’ knowledge, attitudes and practices concerning antibiotic use simultaneously across different healthcare course types. We conducted a cross-sectional multi-center survey among UK [...] Read more.

The Global Action Plan on Antimicrobial Resistance highlights the importance of training all healthcare professionals. No study has assessed patterns of students’ knowledge, attitudes and practices concerning antibiotic use simultaneously across different healthcare course types. We conducted a cross-sectional multi-center survey among UK students. The survey was advertised through local survey coordinators at 25 universities. The online survey was accessible from 10th October to 17th November 2016 (before European Antibiotic Awareness Day). A total of 255 students from 25 universities participated, including students on medicine, pharmacy, nursing, physician associate, dentistry and veterinary medicine courses. Antibiotic resistance was considered to be a more important global challenge than climate change, obesity or food security (p < 0.001). Most students (95%) believed that antibiotic resistance will be a problem for their future practice, but fewer (69%) thought that the antibiotics they will prescribe, administer or dispense will contribute to the problem. A fifth of students felt they had sufficient knowledge of antibiotic use for their future work. Our exploratory study suggests that UK human and animal healthcare students are aware of the importance of antibiotic resistance, but many still have certain misconceptions. Campaigns and improved educational efforts applying behavioral insights methodology could address these. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessArticle

Evidence for Anti-Pseudogymnoascus destructans (Pd) Activity of Propolis

by Soumya Ghosh, Robyn McArthur, Zhi Chao Guo, Rory McKerchar, Kingsley Donkor, Jianping Xu and Naowarat Cheeptham

Antibiotics 2018, 7(1), 2; https://doi.org/10.3390/antibiotics7010002 - 21 Dec 2017

Cited by 6 | Viewed by 6187

Abstract

White-nose syndrome (WNS) in bats, caused by Pseudogymnoascus destructans (Pd), is a cutaneous infection that has devastated North American bat populations since 2007. At present, there is no effective method for controlling this disease. Here, we evaluated the effect of propolis [...] Read more.

White-nose syndrome (WNS) in bats, caused by Pseudogymnoascus destructans (Pd), is a cutaneous infection that has devastated North American bat populations since 2007. At present, there is no effective method for controlling this disease. Here, we evaluated the effect of propolis against Pd in vitro. Using Sabouraud dextrose agar (SDA) medium, approximately 1.7 × 10⁷ conidia spores of the Pd strain M3906-2/mL were spread on each plate and grown to form a consistent lawn. A Kirby–Bauer disk diffusion assay was employed using different concentrations of propolis (1%, 2%, 3%, 4%, 5%, 10%, 15%, 20%, 25%), in plates incubated at 8 °C and 15 °C. At 8 °C and 15 °C, as the concentration of propolis increased, there was an increasing zone of inhibition (ZOI), reaching the highest degree at 10% and 25% concentrations, respectively. A germule suppression assay showed a similar effect on Pd conidia germination. A MALDI-TOF-MS analysis of propolis revealed multiple constituents with a potential anti-Pd activity, including cinnamic acid, p-coumaric acid, and dihydrochalcones, which could be further tested for their individual effects. Our study suggests that propolis or its individual constituents might be suitable products against Pd. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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2331 KiB

Open AccessArticle

Sperm Quality during Storage Is Not Affected by the Presence of Antibiotics in EquiPlus Semen Extender but Is Improved by Single Layer Centrifugation

by Ziyad Al-Kass, Joachim Spergser, Christine Aurich, Juliane Kuhl, Kathrin Schmidt, Anders Johannisson and Jane M. Morrell

Antibiotics 2018, 7(1), 1; https://doi.org/10.3390/antibiotics7010001 - 21 Dec 2017

Cited by 12 | Viewed by 6726

Abstract

Contamination of semen with bacteria arises during semen collection and handling. This bacterial contamination is typically controlled by adding antibiotics to semen extenders but intensive usage of antibiotics can lead to the development of bacterial resistance and may be detrimental to sperm quality. [...] Read more.

Contamination of semen with bacteria arises during semen collection and handling. This bacterial contamination is typically controlled by adding antibiotics to semen extenders but intensive usage of antibiotics can lead to the development of bacterial resistance and may be detrimental to sperm quality. The objective of this study was to determine the effects of antibiotics in a semen extender on sperm quality and to investigate the effects of removal of bacteria by modified Single Layer Centrifugation (MSLC) through a colloid. Semen was collected from six adult pony stallions (three ejaculates per male). Aliquots of extended semen were used for MSLC with Equicoll, resulting in four treatment groups: control and MSLC in extender with antibiotics (CA and SA, respectively); control and MSLC in extender without antibiotics (CW and SW, respectively). Sperm motility, membrane integrity, mitochondrial membrane potential and chromatin integrity were evaluated daily by computer-assisted sperm analysis (CASA) and flow cytometry. There were no differences in sperm quality between CA and CW, or between SA and SW, although progressive motility was negatively correlated to total bacterial counts at 0 h. However, MSLC groups showed higher mean total motility (P < 0.001), progressive motility (P < 0.05), membrane integrity (P < 0.0001) and mitochondrial membrane potential (P < 0.05), as well as better chromatin integrity (P < 0.05), than controls. Sperm quality remained higher in the MSLC groups than controls throughout storage. These results indicate that sperm quality was not adversely affected by the presence of antibiotics but was improved considerably by MSLC. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessArticle

Decreasing Inappropriate Use of Antibiotics in Primary Care in Four Countries in South America—Cluster Randomized Controlled Trial

by Inés Urbiztondo, Lars Bjerrum, Lidia Caballero, Miguel Angel Suarez, Monica Olinisky and Gloria Córdoba

Antibiotics 2017, 6(4), 38; https://doi.org/10.3390/antibiotics6040038 - 14 Dec 2017

Cited by 9 | Viewed by 7192

Abstract

High antibiotic prescribing and antimicrobial resistance in patients attending primary care have been reported in South America. Very few interventions targeting general practitioners (GPs) to decrease inappropriate antibiotic prescribing have been investigated in this region. This study assessed the effectiveness of online feedback [...] Read more.

High antibiotic prescribing and antimicrobial resistance in patients attending primary care have been reported in South America. Very few interventions targeting general practitioners (GPs) to decrease inappropriate antibiotic prescribing have been investigated in this region. This study assessed the effectiveness of online feedback on reducing antibiotic prescribing in patients with suspected respiratory tract infections (RTIs) attending primary care. The aim was to reduce antibiotic prescribing in patients with acute bronchitis and acute otitis media. Both are RTIs for which antibiotics have a very limited effect. A cluster randomized two-arm control trial was implemented. Healthcare centres from Bolivia, Argentina, Paraguay and Uruguay participating in the quality improvement program HAPPY AUDIT were randomly allocated to either intervention or control group. During ten consecutive weeks, GPs in the intervention group received evidence-based online feedback on the management of suspected RTIs. In patients with acute bronchitis, the intervention reduced the antibiotic prescribing rate from 71.6% to 56% (control group from 61.2% to 52%). In patients with acute otitis media, the intervention reduced the antibiotic prescribing from 94.8% to 86.2% (no change in the control group). In all RTIs, the intervention reduced antibiotic prescribing rate from 37.4% to 28.1% (control group from 29% to 27.2%). Online evidence-based feedback is effective for reducing antibiotic prescribing in patients with RTIs attending primary care in South America. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessArticle

LC-MS/MS Tandem Mass Spectrometry for Analysis of Phenolic Compounds and Pentacyclic Triterpenes in Antifungal Extracts of Terminalia brownii (Fresen)

by Enass Y. A. Salih, Pia Fyhrquist, Ashraf M. A. Abdalla, Abdelazim Y. Abdelgadir, Markku Kanninen, Marketta Sipi, Olavi Luukkanen, Mustafa K. M. Fahmi, Mai H. Elamin and Hiba A. Ali

Antibiotics 2017, 6(4), 37; https://doi.org/10.3390/antibiotics6040037 - 13 Dec 2017

Cited by 48 | Viewed by 7444

Abstract

Decoctions and macerations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as fungicides on field crops and in traditional granaries in Sudan. In addition, T. brownii water extracts are commonly used as [...] Read more.

Decoctions and macerations of the stem bark and wood of Terminalia brownii Fresen. are used in traditional medicine for fungal infections and as fungicides on field crops and in traditional granaries in Sudan. In addition, T. brownii water extracts are commonly used as sprays for protecting wooden houses and furniture. Therefore, using agar disc diffusion and macrodilution methods, eight extracts of various polarities from the stem wood and bark were screened for their growth-inhibitory effects against filamentous fungi commonly causing fruit, vegetable, grain and wood decay, as well as infections in the immunocompromised host. Ethyl acetate extracts of the stem wood and bark gave the best antifungal activities, with MIC values of 250 µg/mL against Nattrassia mangiferae and Fusarium verticillioides, and 500 µg/mL against Aspergillus niger and Aspergillus flavus. Aqueous extracts gave almost as potent effects as the ethyl acetate extracts against the Aspergillus and Fusarium strains, and were slightly more active than the ethyl acetate extracts against Nattrassia mangiferae. Thin layer chromatography, RP-HPLC-DAD and tandem mass spectrometry (LC-MS/MS), were employed to identify the chemical constituents in the ethyl acetate fractions of the stem bark and wood. The stem bark and wood were found to have a similar qualitative composition of polyphenols and triterpenoids, but differed quantitatively from each other. The stilbene derivatives, cis- (3) and trans- resveratrol-3-O-β-galloylglucoside (4), were identified for the first time in T. brownii. Moreover, methyl-(S)-flavogallonate (5), quercetin-7-β-O-di-glucoside (8), quercetin-7-O-galloyl-glucoside (10), naringenin-4′-methoxy-7-pyranoside (7), 5,6-dihydroxy-3′,4′,7-tri-methoxy flavone (12), gallagic acid dilactone (terminalin) (6), a corilagin derivative (9) and two oleanane type triterpenoids (1) and (2) were characterized. The flavonoids, a corilagin derivative and terminalin, have not been identified before in T. brownii. We reported earlier on the occurrence of methyl-S-flavogallonate and its isomer in the roots of T. brownii, but this is the first report on their occurrence in the stem wood as well. Our results justify the traditional uses of macerations and decoctions of T. brownii stem wood and bark for crop and wood protection and demonstrate that standardized extracts could have uses for the eco-friendly control of plant pathogenic fungi in African agroforestry systems. Likewise, our results justify the traditional uses of these preparations for the treatment of skin infections caused by filamentous fungi. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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192 KiB

Open AccessArticle

Adverse Effects of Amoxicillin for Acute Lower Respiratory Tract Infection in Primary Care: Secondary and Subgroup Analysis of a Randomised Clinical Trial

by Meera Tandan, Akke Vellinga, Robin Bruyndonckx, Paul Little, Theo Verheij, Chris C Butler, Herman Goossens and Samuel Coenen

Antibiotics 2017, 6(4), 36; https://doi.org/10.3390/antibiotics6040036 - 13 Dec 2017

Cited by 5 | Viewed by 6148

Abstract

A European placebo-controlled trial of antibiotic treatment for lower respiratory tract infection (LRTI) conducted in 16 primary care practices networks recruited participants between November 2007 and April 2010, and found adverse events (AEs) occurred more often in patients prescribed amoxicillin compared to placebo. [...] Read more.

A European placebo-controlled trial of antibiotic treatment for lower respiratory tract infection (LRTI) conducted in 16 primary care practices networks recruited participants between November 2007 and April 2010, and found adverse events (AEs) occurred more often in patients prescribed amoxicillin compared to placebo. This secondary analysis explores the causal relationship and estimates specific AEs (diarrhoea, nausea, rash) due to amoxicillin treatment for LRTI, and if any subgroup is at increased risk of any or a specific AE. A total of 2061 patients were randomly assigned to amoxicillin (1038) and placebo (1023); 595 (28%) were 60 and older. A significantly higher proportion of any AEs (diarrhoea or nausea or rash) (OR = 1.31, 95% CI 1.05–1.64, number needed to harm (NNH) = 24) and of diarrhoea (OR 1.43 95% CI 1.08–1.90, NNH = 29) was reported in the amoxicillin group during the first week after randomisation. Subgroup analysis showed rash was significantly more often reported in males prescribed amoxicillin (interaction term 3.72 95% CI 1.22–11.36; OR of amoxicillin in males 2.79 (95% CI 1.08–7.22). No other subgroup at higher risk was identified. Although the study was not powered for subgroup analysis, this analysis suggests that most patients are likely to be equally harmed when prescribed antibiotics. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessArticle

Nisin in Combination with Cinnamaldehyde and EDTA to Control Growth of Escherichia coli Strains of Swine Origin

by Des Field, Inès Baghou, Mary C. Rea, Gillian E. Gardiner, R. Paul Ross and Colin Hill

Antibiotics 2017, 6(4), 35; https://doi.org/10.3390/antibiotics6040035 - 12 Dec 2017

Cited by 24 | Viewed by 7250

Abstract

Post-weaning diarrhoea (PWD) due to enterotoxigenic Escherichia coli (ETEC) is an economically important disease in pig production worldwide. Although antibiotics have contributed significantly to mitigate the economic losses caused by PWD, there is major concern over the increased incidence of antimicrobial resistance among [...] Read more.

Post-weaning diarrhoea (PWD) due to enterotoxigenic Escherichia coli (ETEC) is an economically important disease in pig production worldwide. Although antibiotics have contributed significantly to mitigate the economic losses caused by PWD, there is major concern over the increased incidence of antimicrobial resistance among bacteria isolated from pigs. Consequently, suitable alternatives that are safe and effective are urgently required. Many naturally occurring compounds, including the antimicrobial peptide nisin and a number of plant essential oils, have been widely studied and are reported to be effective as antimicrobial agents against pathogenic microorganisms. Here, we evaluate the potential of nisin in combination with the essential oil cinnamaldehyde and ethylenediaminetetraacetic acid (EDTA) to control the growth of E. coli strains of swine origin including two characterized as ETEC. The results reveal that the use of nisin (10 μM) with low concentrations of trans-cinnamaldehyde (125 μg/mL) and EDTA (0.25–2%) resulted in extended lag phases of growth compared to when either antimicrobial is used alone. Further analysis through kill curves revealed that an approximate 1-log reduction in E. coli cell counts was observed against the majority of targets tested following 3 h incubation. These results highlight the potential benefits of combining the natural antimicrobial nisin with trans-cinnamaldehyde and EDTA as a new approach for the inhibition of E. coli strains of swine origin. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessArticle

Dual Regulation of the Small RNA MicC and the Quiescent Porin OmpN in Response to Antibiotic Stress in Escherichia coli

by Sushovan Dam, Jean-Marie Pagès and Muriel Masi

Antibiotics 2017, 6(4), 33; https://doi.org/10.3390/antibiotics6040033 - 06 Dec 2017

Cited by 18 | Viewed by 6276

Abstract

Antibiotic resistant Gram-negative bacteria are a serious threat for public health. The permeation of antibiotics through their outer membrane is largely dependent on porin, changes in which cause reduced drug uptake and efficacy. Escherichia coli produces two major porins, OmpF and OmpC. MicF [...] Read more.

Antibiotic resistant Gram-negative bacteria are a serious threat for public health. The permeation of antibiotics through their outer membrane is largely dependent on porin, changes in which cause reduced drug uptake and efficacy. Escherichia coli produces two major porins, OmpF and OmpC. MicF and MicC are small non-coding RNAs (sRNAs) that modulate the expression of OmpF and OmpC, respectively. In this work, we investigated factors that lead to increased production of MicC. micC promoter region was fused to lacZ, and the reporter plasmid was transformed into E. coli MC4100 and derivative mutants. The response of micC–lacZ to antimicrobials was measured during growth over a 6 h time period. The data showed that the expression of micC was increased in the presence of β-lactam antibiotics and in an rpoE depleted mutant. Interestingly, the same conditions enhanced the activity of an ompN–lacZ fusion, suggesting a dual transcriptional regulation of micC and the quiescent adjacent ompN. Increased levels of OmpN in the presence of sub-inhibitory concentrations of chemicals could not be confirmed by Western blot analysis, except when analyzed in the absence of the sigma factor σ^E. We suggest that the MicC sRNA acts together with the σ^E envelope stress response pathway to control the OmpC/N levels in response to β-lactam antibiotics. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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198 KiB

Open AccessArticle

Activity In Vitro of Clotrimazole against Canine Methicillin-Resistant and Susceptible Staphylococcus pseudintermedius

by Sian-Marie Frosini and Ross Bond

Antibiotics 2017, 6(4), 29; https://doi.org/10.3390/antibiotics6040029 - 22 Nov 2017

Cited by 10 | Viewed by 3890

Abstract

Emergence of multidrug-resistance in Staphylococcus pseudintermedius (SP) has increased interest in topical therapy as an alternative to systemic antibiotics in canine pyoderma. The antifungal imidazole, clotrimazole, is contained in numerous licensed canine ear preparations. Its in vitro activity against SP has not been [...] Read more.

Emergence of multidrug-resistance in Staphylococcus pseudintermedius (SP) has increased interest in topical therapy as an alternative to systemic antibiotics in canine pyoderma. The antifungal imidazole, clotrimazole, is contained in numerous licensed canine ear preparations. Its in vitro activity against SP has not been evaluated, although previous studies have shown that the related imidazole, miconazole, has significant anti-staphylococcal efficacy. We therefore determined minimum inhibitory concentrations (MICs) of clotrimazole amongst 50 SP isolates (25 methicillin-resistant [MR]SP and susceptible [MS]SP) collected from dogs in Germany during 2010–2011 using an agar dilution method (CLSI VET01-A4). MICs amongst MRSP and MSSP were comparable (MIC₅₀ and MIC₉₀ = 1mg/L for both groups, p = 0.317); overall, 49 isolates had MIC = 1 mg/L and one had MIC = 0.5 mg/L. The relatively low MICs obtained in this study are likely to be exceeded by topical therapy and thus further clinical evaluation of clotrimazole use in canine superficial pyoderma and otitis externa caused by MRSP and MSSP is now warranted. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessFeature PaperArticle

Choline Kinase, A Novel Drug Target for the Inhibition of Streptococcus pneumoniae

by Tahl Zimmerman and Salam Ibrahim

Antibiotics 2017, 6(4), 20; https://doi.org/10.3390/antibiotics6040020 - 25 Sep 2017

Cited by 11 | Viewed by 5011

Abstract

Gram-positive pathogens, such as Streptococcus pneumoniae, can have deleterious effects on both human and animal health. Antibiotics and antimicrobials have been developed to treat infections caused by such pathogens and to prevent food contamination. However, these strategies have been increasingly thwarted [...] Read more.

Gram-positive pathogens, such as Streptococcus pneumoniae, can have deleterious effects on both human and animal health. Antibiotics and antimicrobials have been developed to treat infections caused by such pathogens and to prevent food contamination. However, these strategies have been increasingly thwarted by the emergence of resistant bacteria strains. Thus, new methods for controlling Gram-positive pathogen growth need to be continuously developed. Choline analogs, such as Hemicholinium-3 (HC-3), have been shown to be useful in blocking cell division in eukaryotic cells through the inhibition of choline kinase, an enzyme which catalyzes the production of phosphocholine from choline and ATP. In some Gram-positive pathogens, choline kinase is an important enzyme in the production of the cell wall element, lipoteichoic acid. However, it is not known if inhibiting this enzyme has any effect on cell division in Gram-positive bacteria. Using the R6 strain as a model, we tested the ability of HC-3 to block the activity of choline kinase in S. pneumoniae and inhibit cell growth. Mass-spectrometry measurements of crude extracts revealed that HC-3 blocked choline kinase activity. Turbidity measurements and population counts showed that HC-3 inhibited cell growth. Competition assays with choline suggested that HC-3 also blocked choline transporters. Western blots showed that lipoteichoic acid production was blocked in the presence of HC-3, and autolytic assays showed that this decrease in lipoteichoic acids caused cells to be more resistant to autolysis. Scanning electron microscopy revealed that HC-3 distorted the cell wall. This study thus establishes choline kinase as a novel drug target for S. pneumoniae. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessFeature PaperArticle

Self-Assessment of Antimicrobial Stewardship in Primary Care: Self-Reported Practice Using the TARGET Primary Care Self-Assessment Tool

by Rebecca Owens, Leah Ffion Jones, Michael Moore, Dirk Pilat and Cliodna McNulty

Antibiotics 2017, 6(3), 16; https://doi.org/10.3390/antibiotics6030016 - 16 Aug 2017

Cited by 8 | Viewed by 6301

Abstract

Multifaceted antimicrobial stewardship (AMS) interventions including: antibiotic guidance, reviews of antibiotic use using audits, education, patient facing materials, and self-assessment, are successful in improving antimicrobial use. We aimed to measure the self-reported AMS activity of staff completing a self-assessment tool (SAT). The Royal [...] Read more.

Multifaceted antimicrobial stewardship (AMS) interventions including: antibiotic guidance, reviews of antibiotic use using audits, education, patient facing materials, and self-assessment, are successful in improving antimicrobial use. We aimed to measure the self-reported AMS activity of staff completing a self-assessment tool (SAT). The Royal College of General Practitioners (RCGP)/Public Health England (PHE) SAT enables participants considering an AMS eLearning course to answer 12 short questions about their AMS activities. Questions cover guidance, audit, and reflection about antibiotic use, patient facing materials, and education. Responses are recorded digitally. Data were collated, anonymised, and exported into Microsoft Excel. Between November 2014 and June 2016, 1415 users completed the SAT. Ninety eight percent reported that they used antibiotic guidance for treating common infections and 63% knew this was available to all prescribers. Ninety four percent of GP respondents reported having used delayed prescribing when appropriate, 25% were not using Read codes, and 62% reported undertaking a practice-wide antibiotic audit in the last two years, of which, 77% developed an audit action plan. Twenty nine percent had undertaken other antibiotic-related clinical courses. Fifty six percent reported sharing patient leaflets covering infection. Many prescribers reported undertaking a range of AMS activities. GP practice managers should ensure that all clinicians have access to prescribing guidance. Antibiotic audits should be encouraged to enable GP staff to understand their prescribing behaviour and address gaps in good practice. Prescribers are not making full use of antibiotic prescribing-related training opportunities. Read coding facilitates more accurate auditing and its use by all clinicians should be encouraged. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Review

Jump to: Research

460 KiB

Open AccessReview

Establishing Genotype-to-Phenotype Relationships in Bacteria Causing Hospital-Acquired Pneumonia: A Prelude to the Application of Clinical Metagenomics

by Etienne Ruppé, Abdessalam Cherkaoui, Vladimir Lazarevic, Stéphane Emonet and Jacques Schrenzel

Antibiotics 2017, 6(4), 30; https://doi.org/10.3390/antibiotics6040030 - 29 Nov 2017

Cited by 35 | Viewed by 7620

Abstract

Clinical metagenomics (CMg), referred to as the application of next-generation sequencing (NGS) to clinical samples, is a promising tool for the diagnosis of hospital-acquired pneumonia (HAP). Indeed, CMg allows identifying pathogens and antibiotic resistance genes (ARGs), thereby providing the information required for the [...] Read more.

Clinical metagenomics (CMg), referred to as the application of next-generation sequencing (NGS) to clinical samples, is a promising tool for the diagnosis of hospital-acquired pneumonia (HAP). Indeed, CMg allows identifying pathogens and antibiotic resistance genes (ARGs), thereby providing the information required for the optimization of the antibiotic regimen. Hence, provided that CMg would be faster than conventional culture, the probabilistic regimen used in HAP could be tailored faster, which should lead to an expected decrease of mortality and morbidity. While the inference of the antibiotic susceptibility testing from metagenomic or even genomic data is challenging, a limited number of antibiotics are used in the probabilistic regimen of HAP (namely beta-lactams, aminoglycosides, fluoroquinolones, glycopeptides and oxazolidinones). Accordingly, based on the perspective of applying CMg to the early diagnostic of HAP, we aimed at reviewing the performances of whole genomic sequencing (WGS) of the main HAP-causing bacteria (Enterobacteriaceae, Pseudomonas aeruginosa, Acinetobacter baumannii, Stenotrophomonas maltophilia and Staphylococcus aureus) for the prediction of susceptibility to the antibiotic families advocated in the probabilistic regimen of HAP. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Open AccessReview

Ubiquitous Nature of Fluoroquinolones: The Oscillation between Antibacterial and Anticancer Activities

by Temilolu Idowu and Frank Schweizer

Antibiotics 2017, 6(4), 26; https://doi.org/10.3390/antibiotics6040026 - 07 Nov 2017

Cited by 69 | Viewed by 12688

Abstract

Fluoroquinolones are synthetic antibacterial agents that stabilize the ternary complex of prokaryotic topoisomerase II enzymes (gyrase and Topo IV), leading to extensive DNA fragmentation and bacteria death. Despite the similar structural folds within the critical regions of prokaryotic and eukaryotic topoisomerases, clinically relevant [...] Read more.

Fluoroquinolones are synthetic antibacterial agents that stabilize the ternary complex of prokaryotic topoisomerase II enzymes (gyrase and Topo IV), leading to extensive DNA fragmentation and bacteria death. Despite the similar structural folds within the critical regions of prokaryotic and eukaryotic topoisomerases, clinically relevant fluoroquinolones display a remarkable selectivity for prokaryotic topoisomerase II, with excellent safety records in humans. Typical agents that target human topoisomerases (such as etoposide, doxorubicin and mitoxantrone) are associated with significant toxicities and secondary malignancies, whereas clinically relevant fluoroquinolones are not known to exhibit such propensities. Although many fluoroquinolones have been shown to display topoisomerase-independent antiproliferative effects against various human cancer cells, those that are significantly active against eukaryotic topoisomerase show the same DNA damaging properties as other topoisomerase poisons. Empirical models also show that fluoroquinolones mediate some unique immunomodulatory activities of suppressing pro-inflammatory cytokines and super-inducing interleukin-2. This article reviews the extended roles of fluoroquinolones and their prospects as lead for the unmet needs of “small and safe” multimodal-targeting drug scaffolds. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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Identification and Antimicrobial Susceptibility Testing of Anaerobic Bacteria: Rubik’s Cube of Clinical Microbiology?

by Márió Gajdács, Gabriella Spengler and Edit Urbán

Antibiotics 2017, 6(4), 25; https://doi.org/10.3390/antibiotics6040025 - 07 Nov 2017

Cited by 112 | Viewed by 14446

Abstract

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the [...] Read more.

Anaerobic bacteria have pivotal roles in the microbiota of humans and they are significant infectious agents involved in many pathological processes, both in immunocompetent and immunocompromised individuals. Their isolation, cultivation and correct identification differs significantly from the workup of aerobic species, although the use of new technologies (e.g., matrix-assisted laser desorption/ionization time-of-flight mass spectrometry, whole genome sequencing) changed anaerobic diagnostics dramatically. In the past, antimicrobial susceptibility of these microorganisms showed predictable patterns and empirical therapy could be safely administered but recently a steady and clear increase in the resistance for several important drugs (β-lactams, clindamycin) has been observed worldwide. For this reason, antimicrobial susceptibility testing of anaerobic isolates for surveillance purposes or otherwise is of paramount importance but the availability of these testing methods is usually limited. In this present review, our aim was to give an overview of the methods currently available for the identification (using phenotypic characteristics, biochemical testing, gas-liquid chromatography, MALDI-TOF MS and WGS) and antimicrobial susceptibility testing (agar dilution, broth microdilution, disk diffusion, gradient tests, automated systems, phenotypic and molecular resistance detection techniques) of anaerobes, when should these methods be used and what are the recent developments in resistance patterns of anaerobic bacteria. Full article

(This article belongs to the Special Issue Top 35 of Antibiotics Travel Awards 2017)

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