ABSTRACT
Isolation of Xanthomonas campestris from soil has a wide range of applications from monitoring of phytopathogenic populations in soil to screening of improved xanthan-producing strains. Identification of Xanthomonas campestris and its pathovars requires pathogenicity tests in addition to phenotypic and molecular characterization. Thirty phenotypic tests were carried out on 57 yellow-pigmented bacterial isolates obtained from soil of cabbage farms after screening on Selective Xanthomonas [SX] agar and transferring on Yeast Malt agar. Absorption spectra of pigments and capability of biopolymer production were determined for the isolates. Some characteristics of the biopolymer produced and presence of a X. campestris-specific gene marker were investigated for nine putative X. campestris isolates. The present study introduces a set of simple phenotypic tests including urease, acid production from sucrose, mucoid growth on 5% sucrose, starch hydrolysis, growth in 4% NaCl, motility and utilization of asparagine as sole carbon and nitrogen source for quick and inexpensive tentative identification of Xanthomonas campestris. Validation of these tests was confirmed in 100% of the cases by characterization of bacterial exopolysaccharide as xanthan and production of genus-specific xanthomonadin pigment. Moreover, tracking of hrc gene among putative X. campestris isolates gave positive results in 80% of cases. The Minimal simple phenotypic tests facilitate the screening and differentiation of putative X. campestris isolates from other false bacterial strains isolated from soil on semiselective SX agar
Subject(s)
Biopolymers , Soil Microbiology , Mass Screening , Plant Diseases/microbiology , Plant PathologyABSTRACT
The vitreoretinal interface is involved in a wide range of vitreoretinal disorders and separation of the posterior vitreous face from the retinal surface is an essential part of vitrectomy surgeries. A diverse range of enzymatic and non-enzymatic agents are being studied as an adjunct before or during vitrectomy to facilitate the induction of posterior vitreous detachment. There is a significant body of knowledge in the literature about different vitreolytic agents under investigation for a variety of pathologies involving the vitreoretinal interface which will be summarized in this review. Articles retrieved by Pubmed search using keywords "Vitreolysis", pharmacologic Vitreolysis, plasmin and vitrectomy, and microplasmin and vitrectomy, were used in this review. recent reports have raised strong hopes that pharmacologic vitreolysis may eventually find its way to clinical practice. Further investigations will demonstrate whether enzymatic vitreolysis could be used as an adjunct and/or alternative treatment for treatment of vitreoretinal disorders
ABSTRACT
Bacterial cells of Staphylococcus epidermidis are naturally occurring on skin and human mucosal membranes. They also cause nosocomial infections. Capability of biofilm formation plays an important role in the bacterial virulence. Quinolones have been used to treat urinary tract infections caused by S. epidermidis for several years. Thus, resistance to this type of antibiotics has emerged among the strains of this organism. Since the bacterial cells residing within biofilm structures are more resistant than those in planctonic stage, we conduct this study to examine the effect of quinolones was the main goal of ones study of higher resistance of native biofilm producing strains is the goal of this project. In this research ten native isolates of S. epidermidis were obtained from patients with urinary tract infection. Also standard strain of S. epidermidis PTCC 1435 was used as a control. Identification of strains was confirmed using morphological and biochemical tests. Challenge tests against the isolated was performed using three quinolone antibiotics including Ciprofluxacin, Ofluxacin, Nalidixic acid, with two different procedures: kirby bauer disk diffusion test, and broth dilution test. Average of MICs of above mentioned antibiotics against ten isolated was obtained as follow: Ciprofluxacin [7/375 micro g /micro l], Ofluxacin [11/53 micro g /micro l], Nalidixic acid [2597 /2 micro g /micro l]. Experimental biofilm model of these bacteria showed much higher resistance to quinolone antibiotic, from 15 times in case of Nalidixic acid to 18 times greater resistance in case of Ciprofluxacin. Average of MICs among ten isolates against the three antibiotics also showed increased resistance as follow: Ciprofluxacin [128/4 micro g /micro l], Ofluxacin [177/8 micro g /micro l], Nalidixic acid [3942/4 micro g /micro l]. S. epidermidis showed increased resistance to different quinolone antibiotics in biofilm structure, comparing to those of planktonic form. Results obtained from this research is in agreement with those of other similar projects; and emphesize on applying of adequate doses of antibiotics against urinary infection caused by biofilmic Staphylococcus epidermidis