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1.
B. Üstündag M. Cay M. Naziroglu N. Dilsiz M. J. C. Crabbe N. Ilhan 《Cell biochemistry and function》1999,17(3):193-198
It is generally accepted that hypertension and other vascular pathologies increase in diabetes mellitus (DM) patients as a result of the renin–angiotensin–aldosterone (RAA) system. In this study, changes in the renin‐angiotensin‐aldosterone (RAA) system level was determined in Streptozotocin (STZ)‐injected rats. A total of 46 female Wistar albino rats (180–220 g body weight) was utilized in these experiments. STZ was given intraperitoneally to induce diabetes in rats. Streptozotocin (60 mg kg−1 body weight) was dissolved in 0·1 m citrate–‐phosphate buffer (pH 4–5). The non‐diabetic rats were injected with sterilized buffer alone to act as a control group. Blood glucose levels were 398±8·2 mg dl−1, 488±11·75 mg dl−1 and 658±29·6 mg dl−1 at days 3, 12 and 30 respectively. The level of plasma renin activity (PRA) was measured as 7·69±1·07 ng ml−1 h−1; 1·82±0·22 ng ml−1 h−1 and 0·67±0·12 ng ml−1 h−1 at days 3, 12 and 30, respectively. These values showed that the PRA levels are decreased with increased time period. Serum angiotensin converting enzyme (ACE, E.C. 3.4.15.1) levels were increased at days 12 and 30 (p<0·05 and p<0·005), whereas serum aldosterone levels were increased at days 3 and 12 (p<0·05). The level of urea and creatinine increased at days 12 and 30 (p<0·05 and p<0·005, respectively) when compared to the control group. The data from these experiments indicate that the PRA level decreased whereas ACE activity level increased in diabetic rats compared with the control. Aldosterone levels increased at the first stage of the experiment, but then decreased by the end of the experiment as a result of changes in renin and ACE levels. Copyright © 1999 John Wiley & Sons, Ltd. 相似文献
2.
《Journal of Fermentation Technology》1988,66(1):85-91
The effect of glucose feeding on bacitracin production was investigated by fed-batch culture of Bacillus licheniformis. In batch culture, bacitracin secretion was induced after the glucose initially contained in the medium was completely consumed. The concentration of bacitracin, however, increased to no more than 340 units·ml−1 in the batch cultivations. Therefore, additional glucose was supplied after exhaustion of the initial glucose. The effect of glucose feeding on bacitracin biosynthesss was investigated in two ways, the pH-stat modal feeding method and the CO2-dependent feeding method. A kinetic study of bacitracin production found that some glucose was necessary, even during the bacitracin production phase. Excessive feeding of glucose, however, caused a reduction in bacitracin biosynthetic activity. When 50 g·l−1 of defatted soy bean meal (SBM) was used, the bacitracin concentration reached 670 units·ml−1 with the pH-stat modal feeding method and 610 units·ml−1 with the CO2-dependent feeding method, respectively. The yield of bacitracin from consumed glucose was better for the pH-stat method. Using this control strategy, the highest concentration of bacitracin (940 units·ml−1) was obtained with 150 g·l−1 of SBM. 相似文献
3.
Aims: To isolate and characterize bacteria capable of degrading nicotine from the rhizospheric soil of a tobacco plant and to use them to degrade the nicotine in tobacco solid waste. Methods and Results: A bacterium, strain S33, was newly isolated from the rhizospheric soil of a tobacco plant, and identified as Agrobacterium sp. based on morphology, physiological tests, Biolog MicroLog3 4·20 system and 16S rRNA gene sequence. Using nicotine as the sole source of carbon and nitrogen in the medium, it grew optimally with 1·0 g l?1 of nicotine at 30°C and pH 7·0, and nicotine was completely degraded within 6 h. The resting cells prepared from the glucose‐ammonium medium or LB medium could not degrade nicotine within 10 h, while those prepared from the nicotine medium could completely degrade 3 g l?1 of nicotine in 1·5 h at a maximal rate of 1·23 g nicotine h?1 g?1 dry cell. Using the medium containing nicotine, glucose and ammonium simultaneously to cultivate strain S33, the resting cells could degrade 98·87% of nicotine in tobacco solid waste with the concentration as 30 mg nicotine g?1 dry weight tobacco solid waste within 7 h at a maximal rate of 0·46 g nicotine h?1 g?1 dry cell. Conclusions: This is the first report that Agrobacterium sp. has the ability to degrade nicotine. Agrobacterium sp. S33 could use nicotine as the sole source of carbon and nitrogen. The use of resting cells of the strain S33 prepared from the nicotine–glucose–ammonium medium was an effective method to degrade nicotine and detoxify tobacco solid waste. Significance and Impact of the Study: Nicotine in tobacco wastes is both toxic and harmful to human health and the environment. This study showed that Agrobacterium sp. S33 may be suitable for the disposal of tobacco wastes and reducing the nicotine content in tobacco leaves. 相似文献
4.
2-phenylethanol (2-PE) is a higher alcohol widely used in industry that can be obtained by solid-state fermentation (SSF) using low-cost raw materials. This report describes the 2-PE production potential of an indigenous Pichia kudriavzevii isolated from solid-state fermented sugarcane bagasse that possesses attractive characteristics for processing waste streams such as its low-pH tolerance, high growth rate and temperature resistance. Besides, 2-PE production was optimized in batch-SSF using sugarcane bagasse supplemented with l-phenylalanine as substrate. Full factorial design allowed identifying the pH adjustment, micronutrient addition, inoculum and co-substrate load effects, and response surface methodology served to identify the maximum production based on temperature, initial moisture content (MC0) and specific airflow rate (SAFR). While the pH adjustment and micronutrient addition did not affect the 2-PE production, temperature and MC0 resulted critical for the process. After optimization, the maximum 2-PE content was 27.2 ± 0.2 mg per gram of dry substrate at 31 °C, 76 % MC0 and 0.129 L h−1 g−1 SAFR. This result was 23.8 % higher than the sub-optimal condition, and it is the highest 2-PE production via SSF reported so far. These results confirm the ability of P. kudriavzevii for producing 2-PE, and its potential for using waste streams as substrate. 相似文献
5.
B. Wang N. Zhang P. Gong J. Li X. Wang X. Li F. Wang K. Cai X. Zhang 《Letters in applied microbiology》2021,73(2):124-131
Using nematophagous fungi for the biological control of animal parasitic nematodes will become one of the most promising strategies in the search for alternative chemical drugs. The purpose of this study was to check the in vitro activity of four anthelmintics, four chemical fungicides and two antifungal drugs on the spore germination of nematophagous fungi: Duddingtonia flagrans (SF170), Arthrobotrys oligospora (447), Arthrobotrys superba (435) and Arthrobotrys sp. (PS011). A modified 24-well cell culture plate assay was conducted to evaluate the susceptibility of nematophagous fungi against drugs tested by calculating the effective middle concentrations (EC50) of each tested drug to inhibit the germination of fungal spores. EC50 ranged between 0·7 and 47·2 μg ml−1 for fenbendazole, thiabendazole and ivermectin, except levamisole (546·5–4057·8 μg ml−1). EC50 of tested fungicides was 0·6–2·3 μg ml−1 for carbendazim, 55·9–247·4 μg ml−1 for metalaxyl, 24·4–45·2 μg ml−1 for difenoconazole, and 555·9–1438·3 μg ml−1 for pentachloronitrobenzene (PCNB). EC50 of two antifungal drugs was 0·03–3·4 μg ml−1 for amphotericin B and 0·3–10·9 μg ml−1 for ketoconazole. The results showed that 10 tested drugs, except for levamisole and PCNB, had in vitro inhibitory effects on nematophagous fungi. The chlamydospores of D. flagrans had the highest sensitivity to nine tested drugs, except for ketoconazole. 相似文献
6.
Feeding rates of Brachionus plicatilis were studied for two types of food — algae Monochrysis lutheri and baker's yeast Saccharomyces cerevisae. The main regularities of changes in filtration rate and ration were studied in small culture volumes (1 ml) for adult amictic females depending on food concentration (1, 2, 4, 8 and 16 · 106 cells · ml−1), ambient temperature (16 and 26 °C), and salinity (5, 10, 15, 20, 25 and 30 ppt). B. plicatilis ration did not depend on the salinity, but was largely determined by temperature and food concentration. It was found that at 16 and 26 °C the dependence of the ingestion rate (ration) on food concentration differed greatly. A hypothesis was suggested to explain this phenomenon. A critical concentration of both types of food at which the increase in the rotifer ration ceased is 4 · 106 cells · ml−1. This is the minimum “background” food concentration for B. plicatilis mass cultivation. The average rations measured at the concentration of M. lutheri and S. cerevisae of 4 · 106 cells · ml−1 where 1.3 ± 0.1 and 4.8 ± 1.3 μg dry weight. · ind−1 · day−1 at 26 °C and 0.54 ± 0.1 and 1.9 μg d. w. · ind−1 · day−1 at 16 °C, respectively. The rations obtained in the laboratory were corrected for the conditions of rotifer commercial production in the open field in summer time. The correct values were 0.86 and 0.72 μg d. w. · ind−1 · day−1 for algae and yeast, respectively. 相似文献
7.
Aims: To develop probiotics for the control of vibriosis caused by Vibrio anguillarum and Vibrio ordalii in finfish. Methods and Results: Kocuria SM1, isolated from the digestive tract of rainbow trout, was administered orally to rainbow trout (Oncorhynchus mykiss) for 2 weeks at a dose equivalent to c. 108 cells per g of feed and then challenged intraperitoneally with V. anguillarum and V. ordalii. Use of SM1 led to a reduction in mortalities to 15–20% compared to 74–80% mortalities in the controls. SM1 stimulated both cellular and humoral immune responses in rainbow trout, by elevation of leucocytes (5·5 ± 0·8 × 106 ml?1 from 3·7 ± 0·8 × 106 ml?1), erythrocytes (1·2 ± 0·1 × 108 ml?1 from 0·8 ± 0·1 × 108 ml?1), protein (23 ± 4·4 mg ml?1 from 16 ± 1·3 mg ml?1), globulin (15·7 ± 0·2 mg ml?1 from 9·9 ± 0·1 mg ml?1) and albumin (7·3 ± 0·2 mg ml?1 from 6·1 ± 0·1 mg ml?1) levels, upregulation of respiratory burst (0·05 ± 0·01 from 0·02 ± 0·01), complement (56 ± 7·2 units ml?1 from 40 ± 8·0 units ml?1), lysozyme (920 ± 128·8 units ml?1 from 760 ± 115·3 units ml?1) and bacterial killing activities. Conclusions: Kocuria SM1 successfully controlled vibriosis in rainbow trout, and the mode of action reflected stimulation of the host innate immune system. Significance and Impact of the Study: Probiotics can contribute a significant role in fish disease control strategies, and their use may replace some of the inhibitory chemicals currently used in fish farms. 相似文献
8.
9.
《Biomass》1990,21(4):285-295
Seventy-two strains of bacteria representing 39 genera and one yeast (Candida albicans) were screened for ability to hydrolyze chitin. Chitin hydrolysis was determined by a clear zone surrounding colonies growing on the surface of chitin agar. Species with the largest clear zone to colony size (CZ/CS) ratio were further compared for chitinolysis by assaying the level of reducing sugar produced in broth culture. Three yeasts and one bacterial strain known to produce ethanol from glucose were compared for their abilities to produce ethanol from amino sugars. Of the 72 strains screened, 23 produced CZ/CS ratios ranging from 0·38 to 2·5. The highest ratios were observed for strains in the genera: Bacillus and Serratia, followed by Micrococcus, Aeromonas, Vibrio, Clostridium and Plesiomonas. The other species examined produced ratios of less than 1 or were unable to hydrolyze chitin.Hansenula anomala, Pachysolen tannophilus, Saccharomyces cerevisiae, and Zymomonas mobilis were compared for their abilities to grow on and produce ethanol from glucose, glucosamine, and N-acetylglucosamine (NAG). Saccharomyces cerevisiae and H. anomala produced ethanol only from glucose. Pachysolen tannophilus and Z. mobilis produced ethanol from glucose, glucosamine and NAG. The highest concentration of ethanol produced from amino sugar was 598 μg ml−1 from 10 mg ml−1 glucosamine by Z. mobilis. This level was achieved only when yeast extract was included in the medium. Saccharomyces cerevisiae did not grow on glucosamine and Z. mobilis did not grow well on NAG. 相似文献
10.
《Cytotherapy》2020,22(11):690-697
Background aims. Cryopreserved cord blood units (CBUs) can be exposed to transient warming events (TWEs) during routine banking operations, which may affect their potency. NetCord-FACT guidelines recommend removal of these CBUs from inventory. The objective of this work was to evaluate warming kinetics of frozen CBUs in different settings to determine the optimal working environment and define the impact of different TWE scenarios on CB post-thaw quality and potency.MethodsThe warming kinetics of frozen CBUs was influenced by both working surfaces and ambient working temperature, with cold plates providing better protection than vinyl or metal surfaces. Measurement of time for required operational activities revealed that CBUs are probably exposed to core temperatures greater than –150°C even when cold plates are used to reduce warming rates.ResultsOn the basis of the warming kinetics and observed operational activities, three TWE causing scenarios (control, typical, worst case) were investigated using a pool-and-split design and cell viability, recovery and potency (colony-forming unit [CFU]) assays were performed. TWEs were found to have little impact on the recovery of total nucleated cells or on the viability of CD34+ cells. In contrast, the viability and recovery of CD45+ cells in the smaller CBU compartments were reduced by TWEs. Moreover, the worst-case TWE reduced CFU recovery from CBUs, whereas the typical-scenario TWE had little effect. Conclusions. Our results demonstrate that the distal segment underestimates the viability and potency of CBUs and that TWEs can affect the post-thaw viability and potency of CBUs. Although TWEs are almost inevitable during cord-blood banking operations, their effects must be diminished by reducing exposure time, using cold plates and strict operational protocols, to prevent worst-case TWEs. 相似文献
11.
12.
《Process Biochemistry》1999,34(4):341-347
The influence of initial glucose concentrations on the production of biomass and lutein by Chlorella protothecoides CS-41 was investigated in batch cultures using both shake flasks and fermentors. The maximum biomass concentration increased from 4·9 to 31·2 g litre−1 dry cells with an increase in initial glucose concentration from 10 to 80 g litre−1. An even higher initial glucose concentration (100 g litre−1) resulted in a lower biomass concentration, a lower specific growth rate, a lower growth yield coefficient and a considerably longer lag phase, which might be due to substrate inhibition. The initial glucose level also had a significant effect on the production of lutein. In a 3·7-litre fermentor an increase in lutein production from 19·39 to 76·56 mg litre−1 was obtained with an increase in initial glucose concentration from 10 to 40 g litre−1, within which range, lutein yield coefficient was constant (YItn=1·90±0·02 mg g−1). A simple substrate inhibition model was developed, which fitted the experimental data better than the classical Haldane model. A group of time-dependent kinetic models for algal cultivation in fermentors were also constructed, which were in good agreement with the experimental results and could be employed to predict the production of biomass and lutein, and the consumption of glucose in fermentor cultures. 相似文献
13.
Determination of Eubacterial and Cyanobacterial Size and Number in Lake Baikal Using Epifluorescence
Martin E. Boraas David W. Bolgrien Dale A. Holen 《International Review of Hydrobiology》1991,76(4):537-544
Chroococcoid cyanobacteria, (mean size = 0.79 μm, likely Synchetocystis limnetica Popovsk) and total eubacteria (mean size = 0.33 μm), from Lake Baikal, USSR, were enumerated using epifluorescence microscopy and sized with image analysis. Bacterial densities ranged from 0.44 · 106 cells ml−1 at 250 m to 2.3 · 106 cells ml−1 at the surface. Mean eubacterial abundance was 1.3 · 106 cells ml−1. Cyanobacterial densities were more variable, ranging from 0.42 · 104 cells ml−1 at 250 m to 9.8 · 104 cells ml−1 at the surface, with a mean abundance of 2.7 · 104 cells ml−1. The cyanobacteria, in particular, occurred in clusters resembling “marine snow”. Our results indicate that Lake Baikal picoplankton size and density are similar to other large lakes but may have a more diverse community structure than in other large oligotrophic lakes. 相似文献
14.
A.M. Mohamed D.A. Cifuente S.E. Satorres C.M. Mattana 《Letters in applied microbiology》2022,74(3):419-428
Microbial resistance to antibiotics affects the control of clinical infections and is a growing concern in global public health. One important mechanism whereby micro-organisms acquire resistance is biofilm formation. This context has led to the investigation of new antimicrobial substances from plants popularly used in folk medicine. In this work, we studied the antimicrobial and antibiofilm activity of Zinnia peruviana roots, ziniolide (major root metabolite) and aerial parts against Staphylococcus aureus, Staphylococcus epidermidis, Listeria monocytogenes, Escherichia coli, Pseudomonas aeruginosa and Candida albicans. The minimum inhibitory and minimum microbicidal concentration and inhibition of biofilm production was determined. All Z. peruviana extracts showed antimicrobial activity, but that corresponding to the roots was the most active one. The best inhibitory and microbicidal activity was detected against Gram-positive bacteria (0·039–0·078 mg ml−1). The acetonic extract from Z. peruviana leaves showed moderate activity against Gram-positive bacteria (0·625 mg ml−1). Acetonic extract of Z. peruviana flowers showed weak activity (1·25–5 mg ml−1). All the extracts tested showed inhibition of biofilm formation, as well as the ziniolide, however, roots and flowers extracts showed higher antibiofilm activity particularly against Staphylococcus, Listeria and Candida. The extracts tested may be a promising natural alternative for the control of microbial infections. 相似文献
15.
《Process Biochemistry》1999,34(3):295-301
When BmN-4 and M-BmN cells were grown in shake flasks, the pH initially dropped and later increased. The increase in pH signaled a ‘metabolic switch’ that was used here as an indicator for initiating a supplemental glucose and glutamine feed. Using the pH-based fed-batch culture method described, the maximum cell densities of BmN-4 cells and M-BmN cells were increased from 30×105 cells ml−1 to 43×105 and 52×105 cells ml−1, respectively. Correspondingly, the production of polyhedra (4·5×105 OBs ml−1) and HBsAg (574 ng ml−1), from the infection of BmN-4 and M-BmN by wild-type and recombinant BmNPV viruses, respectively, were both significantly enhanced 50% and 100%, respectively. This feeding strategy was implemented with no advanced instrumentation yet facilitated significantly increased yield in shake flasks. The technique should benefit those in research laboratories employing the baculovirus expression system as a rapid and efficient production system. 相似文献
16.
Huayi Liu Yujuan Tian Yi Zhou Yeyi Kan Tingting Wu Wenhai Xiao Yunzi Luo 《Microbial biotechnology》2021,14(6):2605-2616
Tyrosol and its glycosylated product salidroside are important ingredients in pharmaceuticals, nutraceuticals and cosmetics. Despite the ability of Saccharomyces cerevisiae to naturally synthesize tyrosol, high yield from de novo synthesis remains a challenge. Here, we used metabolic engineering strategies to construct S. cerevisiae strains for high-level production of tyrosol and salidroside from glucose. First, tyrosol production was unlocked from feedback inhibition. Then, transketolase and ribose-5-phosphate ketol-isomerase were overexpressed to balance the supply of precursors. Next, chorismate synthase and chorismate mutase were overexpressed to maximize the aromatic amino acid flux towards tyrosol synthesis. Finally, the competing pathway was knocked out to further direct the carbon flux into tyrosol synthesis. Through a combination of these interventions, tyrosol titres reached 702.30 ± 0.41 mg l−1 in shake flasks, which were approximately 26-fold greater than that of the WT strain. RrU8GT33 from Rhodiola rosea was also applied to cells and maximized salidroside production from tyrosol in S. cerevisiae. Salidroside titres of 1575.45 ± 19.35 mg l−1 were accomplished in shake flasks. Furthermore, titres of 9.90 ± 0.06 g l−1 of tyrosol and 26.55 ± 0.43 g l−1 of salidroside were achieved in 5 l bioreactors, both are the highest titres reported to date. The synergistic engineering strategies presented in this study could be further applied to increase the production of high value-added aromatic compounds derived from the aromatic amino acid biosynthesis pathway in S. cerevisiae. 相似文献
17.
Aida G. Infante 《International Review of Hydrobiology》1997,82(4):469-477
Lake Valencia is heavily polluted by waste water of domestic, agricultural and industrial origin. The high organic load may have produced important changes in the limnological properties. Cyanobacteria dominated in numbers and biomass (over 90% throughout the year). Chlorophyll-a content averaged 37.7 + 15 μg · 1−1. Maximum concentrations of 50–80 μg · 1−1 were found near the inflows affected by organically polluted affluents. There has been a 50% reduction in the euphotic zone in only 13 years. The maximum rate of gross photosynthesis per hour at light saturation was determined within the uppermost 1-meter layer. The highest value was 16,290 mg O2 · m−3 · h−1. Lake Valencia is among the most productive lakes in the world, with areal net photosynthesis averaging 7.5 g C · m−2 · d−1. 相似文献
18.
K. Chinachanta A. Shutsrirung L. Herrmann D. Lesueur 《Letters in applied microbiology》2022,74(3):354-366
Indole-3-acetic acid (IAA) synthesis is a major property of rhizosphere bacteria. The IAA-producing ability of rhizobacteria may be influenced by agricultural management. We therefore evaluated the IAA-producing potential of rhizobacteria isolated during organic rice farming (ORF) and conventional rice farming (CRF) in Thung Kula Rong Hai areas of Thailand. The results indicated that ORF gave a significantly higher percentage of IAA producers (95·8%) than CRF (69·9%). The average IAA values of the ORF isolates were around two times higher than those of the CRF isolates both in the absence (12·8 and 5·8 μg IAA ml−1, respectively) and presence of L-tryptophan (L-Trp) (35·2 and 17·2 μg IAA ml−1, respectively). The 16S rRNA gene sequence analysis indicated that the 23 selected isolates belonged to 8 different genera—Sinomonas sp., Micrococcus sp., Microbacterium sp., Fictibacillus sp., Bacillus sp., Burkholderia sp., Leclercia sp. and Enterobacter sp. Interestingly, only three ORF isolates, i.e. ORF15-20 (Micrococcus sp.), ORF15-21 (Sinomonas sp.) and ORF15-23 (Sinomonas sp.), exhibited high IAA production ability without L-Trp (128·5, 160·8 and 174·7 μg IAA ml−1, respectively). Meanwhile, a slight decrease in IAA production with L-Trp was noticed, suggesting that the L-Trp was not used for the IAA synthesis of these isolates. Biopriming with rhizobacterial isolates significantly enhanced the rate of germination of KDML 105 rice seeds compared to the control. 相似文献
19.
Aims: To investigate the effects of nisin on lactobacilli contamination of yeast during ethanol fermentation and to determine the appropriate concentration required to control the growth of selected lactobacilli in a YP/glucose media fermentation model. Methods and Results: The lowest concentration of nisin tested (5 IU ml?1) effectively controlled the contamination of YP/glucose media with 106 CFU ml?1 lactobacilli. Lactic acid yield decreased from 5·0 to 2·0 g l?1 and potential ethanol yield losses owing to the growth and metabolism of Lactobacillus plantarum and Lactobacillus brevis were reduced by 11 and 7·8%, respectively. Approximately, equal concentrations of lactic acid were produced by Lact. plantarum and Lact. brevis in the presence of 5 and 2 IU ml?1 nisin, respectively, thus demonstrating the relatively higher nisin sensitivity of Lact. brevis for the strains in this study. No differences were observed in the final ethanol concentrations produced by yeast in the absence of bacteria at any of the nisin concentrations tested. Conclusions: Metabolism of contaminating bacteria was reduced in the presence of 5 IU ml?1 nisin, resulting in reduced lactic acid production and increased ethanol production by the yeast. Significance and Impact of the Study: Bacteriocins represent an alternative to the use of antibiotics for the control of bacterial contamination in fuel ethanol plants and may be important in preventing the emergence of antibiotic‐resistant contaminating strains. 相似文献
20.
O.H.F. Raro G.S. Collar R.M.C. da Silva P. Vezzaro M.P. Mott G.R. da Cunha C.V.W. Riche C. Dias J. Caierão 《Letters in applied microbiology》2021,72(6):767-773
Therapeutic options for infections caused by Carbapenem-resistant Enterobacterales (CRE) are restricted and include polymyxins-centred schemes. Evaluation of in vitro susceptibility is difficult and time consuming. Agar-based methodologies are an alternative to broth microdilution (BMD) and we aimed to evaluate the accuracy of those methods among Enterobacterales. A total of 137 non-duplicated CRE were subjected to polymyxin B BMD, agar screening test (Mueller Hinton plates containing 3 µg ml−1 of polymyxin B) and agar dilution (antibiotic serially diluted 0·25–64 µg ml−1). CRE of 42·3% were resistant to polymyxin B (MICs range: 0·25–>64 µg ml−1) and 16·8% presented borderline MICs. Sensitivity, specificity, PPV and NPV were 86·2, 98·7, 98 and 90·7% for screening test and 86·2, 97·5, 96·1 and 90·6% for agar dilution. ME was 0·73 and 1·5% for screening and agar dilution respectively; VME was 5·8% for both techniques. In general, agar-based methods had a good performance. As far as we know, this is the first study to propose an agar screening test using polymyxin B instead of colistin. 相似文献