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Xing Zhang - One of the best experts on this subject based on the ideXlab platform.
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Baseline Sensitivity and Action Mechanism of Propamidine Against Alternaria brassicicola, the Causal Agent of Dark Leaf Spot on Cabbage.
Plant disease, 2019Co-Authors: Yong Wang, Xing Zhang, Miao-miao Wang, Mingxia Zhou, Juntao FengAbstract:In the current study, a total of 53 isolates of Alternaria brassicicola collected from Shaanxi Province of China were characterized for their sensitivity to Propamidine. The EC50 (50% effective concentration) values for Propamidine inhibiting mycelial growth and spore germination ranged from 0.515 to 3.247 µg/ml and 0.393 to 2.982 µg/ml, with average EC50 values of 1.327 ± 0.198 µg/ml and 1.106 ± 0.113 µg/ml, respectively. In greenhouse experiments, Propamidine at 100 µg/ml provided >90% efficacy against dark leaf spot on cabbage, which was higher than the efficacy obtained by azoxystrobin at the same concentration. After treatment with Propamidine, fungal growth distortions were observed in the form of excess mycelial branching, thickened cell walls, decreased cell membrane permeability, and increased chitin content. Interestingly, colony color faded after treatment with Propamidine compared with that of the untreated parental isolates. Importantly, the expressions of melanin biosynthesis-associated genes Amr1, Scd1, Brn1, and Brn2 were downregulated at different levels. The obtained baseline sensitivity and control efficacy data suggested that Propamidine inhibited not only growth of A. brassicicola but also melanin biosynthesis, which could reduce the biocompatibility of A. brassicicola in the field. These biological characteristics encourage further investigation of the mechanism of action of Propamidine against A. brassicicola.
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Baseline sensitivity and biochemical responses of Valsa mali to Propamidine.
Pesticide biochemistry and physiology, 2018Co-Authors: Yong Wang, Yang Sun, Juntao Feng, Zi Xiong, Xing ZhangAbstract:Abstract In the current study, baseline sensitivity of Valsa mali to Propamidine was determined using 80 strains collected from apple orchards in Shaanxi Province, China. The median effective concentration (EC 50 ) values for Propamidine inhibiting mycelial growth ranged from 0.086 to 0.852 μg/mL, with a mean of 0.405 ± 0.137 μg/mL. After treated with Propamidine, mycelia were contorted with an increased number of branches, loss of fruiting body production, and decreased cell membrane permeability. Moreover, the enzyme activities of the complexes I, II, IV and ATPase in the mitochondrial respiratory chain were increased significantly, while the enzyme activities of complexes III decreased. Importantly, both on detached leaves and branches of apple trees, Propamidine applied at 100 μg/mL exhibited over 75% protective and curative efficacies, which were even better than the efficacies obtained by carbendazim at the same concentration. These results indicated that Propamidine could be used as an alternative compound in controlling Valsa canker and mitochondrial respiratory chains might be correlated with the action mode of Propamidine. This study encourages further investigation for the action mechanism of Propamidine against plant pathogens and the information could be valuable for synthesis of new antifungal drugs with novel modes of action.
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Sensitivity and biochemical characteristics of Sclerotinia sclerotiorum to Propamidine.
Pesticide biochemistry and physiology, 2016Co-Authors: Yong Wang, Xing Zhang, Yang Sun, Ying Zhang, Yinxing Zhang, Lirong Han, Juntao FengAbstract:Propamidine is an aromatic diamidine compound. In the current study, baseline sensitivity of Sclerotinia sclerotiorum to Propamidine was determined using 78 strains collected from the oilseed rape fields without a previous history of Propamidine usage. The median effective concentration (EC50) values for Propamidine inhibiting mycelial growth ranged from 0.406 to 3.647μg/mL, with a mean of 1.616±0.217μg/mL. There was no correlation between sensitivity to Propamidine and sensitivity to dimethachlon or carbendazim. After treated with Propamidine, mycelia were thinner with irregular distortion and more branches; cell wall became thicker with uneven distribution of cytoplasm than untreated control. In addition, sclerotia production, cell membrane permeability and oxalic acid content significantly decreased. On detached oilseed rape leaves, Propamidine exhibited better control efficacy than carbendazim at the same concentration whether the leaves were inoculated with carbendazim-sensitive or resistant strains. All the results showed that Propamidine exhibited strong antifungal activity and potential application in controlling S. sclerotiorum. Importantly, these data will provide more information on understanding the mode of action of Propamidine against S. sclerotiorum and should be valuable for development of new antifungal drugs.
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Dissipation of Propamidine Fungicide Residues in Greenhouse Tomato
Journal of Agricultural Science, 2013Co-Authors: Laya Kansaye, Jing Zhang, Bao-wei Gao, Xing ZhangAbstract:A method of reverse phase high performance liquid chromatography (RP-HPLC) was established to analyze the dissipation of Propamidine residue in tomato. Residue of Propamidine was extracted from tomato using methanol buffered and determined by RP-HPLC with UV detection at 262 nm. The results showed that the average recoveries of the samples fortified with Propamidine at the concentration range of 25 to 300 mg kg-1 ranged from 87.972 to 106.341% with a relative standard deviation ranged between 0.169 to 3.503%. Initial deposit ranged from 2.45 to 5.70 mg kg-1. The dissipation of Propamidine in tomato followed the first order kinetic equation. The dissipation rate constants in tomato treated with recommended and double recommended dose applied at 4 times and 2 times ranged from 0.110 to 0.151 days, and the corresponding half-lives from 4.589 to 6.300 days. At the day 14 after the last application the residue concentrations of Propamidine in tomato ranged from 0.42 to 0.54 mg kg-1 from the two blocks for all treatments. These Propamidine residues dissipated below the limit of detection of 0.07 mg kg-1 28 days after the last treatment. The results presented in this work and the low toxicity of Propamidine for environment proved that Propamidine will not pose any residual toxicity problem after 14 days of application and tomato fruits could be used safely for human consumption.
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Propamidine decreas mitochondrial complex III activity of Botrytis cinerea.
BMB reports, 2010Co-Authors: Weibo Jin, Feng Juntao, Anliang Chen, Xing ZhangAbstract:Propamidine, an aromatic diamidine compound, is widely used as an antimicrobial agent. To uncover its mechanism on pathogenetic fungi, Botrytis cinerea as an object was used to investigate effects of Propamidine in this paper. The transmission electron microscope results showed that the mitochondrial membranes were collapsed after Propamidine treatment, followed that mitochondria were disrupted. Inhibition of whole-cell and mitochondrial respiration by Propamidine suggested that Propamidine is most likely an inhibitor of electron transport within Botrytis cinerea mitochondria. Furthermore, the mitochondrial complex III activity were inhibited by Propamidine.
John K.g. Dart - One of the best experts on this subject based on the ideXlab platform.
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persistently culture positive acanthamoeba keratitis in vivo resistance and in vitro sensitivity
Ophthalmology, 2003Co-Authors: Juan J Perezsantonja, Melville Matheson, Simon Kilvington, Reanne Hughes, Adnan Tufail, John K.g. DartAbstract:Abstract Purpose To characterize the risk factors, clinical course, treatment outcome and the association between in vivo resistance and in vitro sensitivity for subjects with persistently culture-positive Acanthamoeba keratitis. Design Retrospective noncomparative case series. Participants Eleven subjects with repeatedly positive cultures for Acanthamoeba treated between January 1990 and December 2000, were reviewed. Only subjects with 2 or more positive cultures, availability of the clinical data, and availability of the last Acanthamoeba isolate were included in this study. Methods The medical records were analyzed, and the last isolate from each case was tested in vitro for the antiamoebic drugs used clinically: polyhexamethylene biguanide (PHMB), chlorhexidine, Propamidine and hexamidine. Main outcome measures Risk factors, the clinical outcome and in vitro cysticidal drug sensitivity assay. Results Eleven subjects (11/180, 6.1%) had 2 or more positive cultures of whom 8 eyes of 8 subjects (8/180, 4.45%) were included in this study. Seven of eight (87%) subjects were diagnosed over 1 month from onset (late diagnosis). The most common presenting findings were diffuse stromal infiltrate (5/8, 62.5%), ring infiltrate (5/8, 62.5%), and corneal ulceration (3/8, 37.5%). The clinical course of the disease in all subjects consisted of recurrent episodes of corneal and scleral inflammation, with a mean duration of 13.4 ± 9 months. All subjects received PHMB, and 5/8 (62.5%) chlorhexidine too; hexamidine was used in combination in 6/8 (75%), and Propamidine in 1/8 (12.5%). All subjects had topical steroids, and 5/8 (62.5%) systemic immunosuppression. The disease resolved with corneal scarring in 3/8 (37.5%) subjects, corneal (or impending) perforation treated with therapeutic keratoplasty in 4/8 (50%), and enucleation in 1/8 (12.5%). Final visual acuity was 0.43 ± 0.37. In vitro most isolates were resistant to Propamidine, hexamidine was cysticidal in high concentrations, and PHMB and chlorhexidine had excellent sensitivity profiles. Conclusions In our large series of Acanthamoeba keratitis with a positive microbiologic diagnosis at presentation, nearly 5% developed recurrent episodes of corneal and scleral inflammation with viable Acanthamoeba in the cornea despite prolonged treatment with biguanides and/or diamidines. There was no correlation between in vitro drug sensitivities and the in vivo response for biguanides.
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Outcome of Acanthamoeba Keratitis Treated with Polyhexamethyl Biguanide and Propamidine
Ophthalmology, 1997Co-Authors: I. Graham M. Duguid, John K.g. Dart, Nigel Morlet, Bruce D. Allan, Melville Matheson, Linda A. Ficker, Stephen J. TuftAbstract:Objective: This study investigates the clinical outcome of Acanthamoeba keratitis treated with polyhexamethyl biguanide (PHMB) and Propamidine isethionate (Brolene). Design: A retrospective review of all patients treated for Acanthamoeba keratitis between September 1992 and February 1995 was carried out. All patients were treated with PHMB 0.02% and Propamidine 0.1% hourly for 3 days, the frequency reduced to four to six times daily according to clinical response. Main Outcome Measures: Age, gender, result of laboratory investigation, duration of disease before diagnosis, visual acuity (VA) pretreatment and post-treatment, need for keratoplasty, and presence of adverse reaction were measured. Results: One hundred eleven cases were identified in 105 patients (60 male, 45 female; mean age, 32). Ninety-two percent of infections were in contact lens wearers. The clinical diagnosis was confirmed by corneal culture or histopathology in 64 cases (57.7%). The diagnosis was made "early" (within 28 days) in 65 cases (58.6%). Twentyone (18.9%) were "intermediate" (28 days–2 months) and 20 (18%) were "late" (>2 months) diagnoses. Overall post-treatment VA was 6/12 or better in the majority (88/111, 79.3%) of cases, and 18 (16.2%) had VA of 6/36 or worse. The VA of ≥6/12 was achieved by 90.8% of the early, 71.4% of the intermediate, and 65% of the late groups. Clinical relapses occurred in 19 patients on reducing the therapy. Treatment toxicity was never serious and consisted only of stinging or superficial punctate keratopathy. Keratoplasty was indicated in only ten patients, and disease activity was controlled adequately in all patients before grafting. Conclusions: Combined treatment with PHMB and Propamidine is well tolerated, nontoxic, and effective. Typically, visual outcome is favorable and the requirement for keratoplasty reduced markedly.
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a clinicopathologic study of in vitro sensitivity testing and acanthamoeba keratitis
Investigative Ophthalmology & Visual Science, 1994Co-Authors: M J Elder, S Kilvington, John K.g. DartAbstract:Purpose To examine the extent of any correlation between the in vitro sensitivity and the clinical outcomes of Acanthamoeba keratitis. Methods The clinical outcomes were correlated with the in vitro sensitivity of 23 isolates of 23 patients with culture-positive Acanthamoeba keratitis. The laboratory assay assessed the amoebicidal and cysticidal efficacy of 13 drugs. Results Most agents were effective against the trophozoites in vivo. Polyhexamethylene biguanide (PHMB) and chlorhexidine were the most successful cysticidal agents, followed by sepazonium and Propamidine. Clotrimazole, paramomycin, and ketoconazole were cysticidal in a few specimens, but usually in high concentrations. Neomycin was ineffective against cysts in vivo. Nineteen patients were treated with topical Propamidine and neomycin, and a medical cure was obtained in nine (47%). There was poor correlation between the clinical outcomes of individual cases and the in vitro sensitivity testing. The medical failures were treated with topical PHMB and Propamidine and eight of ten (80%) of these were medically cured. Two patients, however, were still culture positive after 28 and 41 weeks of treatment. PHMB has an excellent in vitro sensitivity profile, but the two cases of failure were sensitive to the drug and resistance had not developed. Conclusions In vitro sensitivity testing has been important in the screening of new agents, although disappointing in the management of individual cases in this set of studies.
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treatment of acanthamoeba keratitis with polyhexamethylene biguanide
Ophthalmology, 1992Co-Authors: Dfp Larkin, S Kilvington, John K.g. DartAbstract:Polyhexamethylene biguanide (PHMB) is a polymeric biguanide disinfectant that has not previously been used in the treatment of infection. Six patients with confirmed Acanthamoeba keratitis were treated with PHMB 0.02%. All patients had uncontrolled keratitis refractory to therapy with multiple conventional antiamebic agents. The rationale for use and the dose of PHMB was determined by in vitro sensitivity testing of the Acanthamoeba corneal isolates to the drugs available for use. Trophozoite forms were sensitive to most agents. Only PHMB was cysticidal at low concentrations in all cases. Sensitivity to the other drugs, including Propamidine, showed wide variation. In 5 of 6 cases, complete resolution of inflammation followed the introduction of PHMB. Toxicity to the ocular surface was not evident with PHMB, unlike Propamidine or neomycin. The reasons for the treatment failure in one case, despite cyst sensitivity to both PHMB and Propamidine, are not clear. PHMB is a promising new treatment for this infection.
Seishi Asari - One of the best experts on this subject based on the ideXlab platform.
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In vitro evaluations of topical agents to treat Acanthamoeba keratitis.
Ophthalmology, 2014Co-Authors: Atsuko Sunada, Keigo Kimura, Isao Nishi, Masahiro Toyokawa, Akiko Ueda, Tomomi Sakata, Takashi Suzuki, Yoshitsugu Inoue, Yuichi Ohashi, Seishi AsariAbstract:To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). Laboratory research. Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% Propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing. The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing. The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, Propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to Propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities. Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and Propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
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In vitro evaluations of topical agents to treat Acanthamoeba keratitis.
Ophthalmology, 2014Co-Authors: Atsuko Sunada, Keigo Kimura, Isao Nishi, Masahiro Toyokawa, Akiko Ueda, Tomomi Sakata, Takashi Suzuki, Yoshitsugu Inoue, Yuichi Ohashi, Seishi AsariAbstract:Purpose To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). Design Laboratory research. Participants Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. Methods The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% Propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing. Main Outcome Measures The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing. Results The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, Propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to Propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities. Conclusions Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and Propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK.
Atsuko Sunada - One of the best experts on this subject based on the ideXlab platform.
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In vitro evaluations of topical agents to treat Acanthamoeba keratitis.
Ophthalmology, 2014Co-Authors: Atsuko Sunada, Keigo Kimura, Isao Nishi, Masahiro Toyokawa, Akiko Ueda, Tomomi Sakata, Takashi Suzuki, Yoshitsugu Inoue, Yuichi Ohashi, Seishi AsariAbstract:To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). Laboratory research. Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% Propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing. The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing. The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, Propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to Propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities. Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and Propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK. Copyright © 2014 American Academy of Ophthalmology. Published by Elsevier Inc. All rights reserved.
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In vitro evaluations of topical agents to treat Acanthamoeba keratitis.
Ophthalmology, 2014Co-Authors: Atsuko Sunada, Keigo Kimura, Isao Nishi, Masahiro Toyokawa, Akiko Ueda, Tomomi Sakata, Takashi Suzuki, Yoshitsugu Inoue, Yuichi Ohashi, Seishi AsariAbstract:Purpose To evaluate the effectiveness of topical agents for the treatment of Acanthamoeba keratitis (AK). Design Laboratory research. Participants Fifty-six Acanthamoeba isolates from 56 patients with clinically proven AK were studied. Methods The effectiveness of 7 agents against Acanthamoeba cysts was determined in vitro. The agents were 1.0% povidone-iodine, 0.05% benzalkonium chloride (BZC), 0.02% chlorhexidine gluconate (CHG), 0.1% Propamidine isethionate, 0.02% polyhexamethylene biguanide (PHMB), 5.0% natamycin, and 1.0% voriconazole (VRCZ). These concentrations are those recommended for patients. In addition, 10-fold dilutions of each of the agents were tested. After exposing the cysts to each agent at 35°C for 1 hour or 24 hours, the agents were removed by centrifugal washing. The exposed cysts were observed by optical microscopy for 7 days. In addition, the fine structures of the exposed isolates were examined by transmission electron microscopy (TEM). The genotype of the isolates was determined by 18S rDNA fragment sequencing. Main Outcome Measures The in vitro susceptibility was determined by complete growth inhibition, and the morphologic appearance was determined by TEM. The genotypes of the 56 isolates were determined by 18S rDNA fragment sequencing. Results The Acanthamoeba cysts were most susceptible to natamycin, followed by povidone-iodine, BZC, PHMB, Propamidine, and CHG. None of the strains was susceptible to VRCZ. The susceptibilities to PHMB and CHG may be time dependent and to Propamidine may be concentration dependent. Transmission electron microscopy showed changes in the inner structure of the cysts exposed to natamycin and povidone-iodine. The Acanthamoeba genotype was T4 in 52 isolates, and cysts with the same genotype had different agent susceptibilities. Conclusions Natamycin and povidone-iodine had excellent cysti-static (or cystcidal) effects, and PHMB and Propamidine did not. There was no correlation between agent effectiveness and Acanthamoeba genotype. Therefore, susceptibility tests of isolates are needed to choose the most appropriate agent, and our results can be a guideline for choosing the most appropriate agent for immediate empirical treatment of AK.
Dorothy K.l. Xing - One of the best experts on this subject based on the ideXlab platform.
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investigation of synergism with combinations of dibromoPropamidine isethionate or Propamidine isethionate and polymyxin b
Journal of Pharmacy and Pharmacology, 1994Co-Authors: Michael R E Richards, Dorothy K.l. XingAbstract:— Combinations of polymyxin B and dibromoPropamidine isethionate exhibited synergistic inhibitory and bactericidal activity against Pseudomonas aeruginosa, Enterobacter cloacae, Proteus mirabilis, Escherichia coli and Staphylococcus aureus. Similar results were obtained with polymyxin B plus Propamidine combinations except that Propamidine was not as active as dibromoPropamidine and the combination of polymyxin B plus Propamidine against S. aureus only had additive activity. The antibacterial agents were tested in solutions and in a cream formulation. The findings indicate a potential for the use of selected combinations of these antibacterial agents in the treatment of wound and superficial eye infections.
