Iodometric Method Research Articles

ANTIOXIDANT ACTIVITY AND TOXICITY EFFECT OF ELEVEN TYPES OF BARK EXTRACTS ACQUIRED FROM EUPHORBIACEAE

The use of natural antioxidants for medicinal purposes deserves thorough attention for their efficacy and possibly adverse toxicity. This paper studies the antioxidant actions and toxicity effects of bark extracts. The study focuses on eleven tree species of Euphorbiaceae family. Initially, bark samples from those trees were extracted using ethanol. The acquired extracts were examined for peroxide values with iodometric method. The bark extracts were chemically screened for possible antioxidant-compound contents, i.e. polyphenols, flavonoids, and saponins; and followed by oxidation-reduction test to assess the extract ability in vitro to scavenge free radicals in their standard sources, i.e. 2,2-diphenyl-1-picrylhydrazyl; altogether to determine qualitatively which species origin from bark extracts afforded the most potential as antioxidants. Toxicity test was performed on those bark extracts to assess their safety on living creatures, particularly humans as tried on shrimp larvae by counting their death, using the Brine Shrimp Lethality Test method. Results show that bark extracts of four plant species, i.e. Acalypha hispida Blume, Bischofia javanica Blume, Glochidion arboreum Blume and Sapium baccatum Roxb species afforded potentiality as antioxidants, because its peroxide value (POV) was lower than or somewhat above those of the positive control vitamin E (POV 89.45 μg/ml). However, bark extracts from Euphorbia antiquorum L, Euphorbia hirta L, and Jatropha podagrica Hook (i.e. LC50 : 238.85; 228.11 & 194.51 μg/ml) were highly toxic, because their LC50’s value< 1000 μg/ml.

Ozone generation process using parallel plates plasma reactor at room temperature

Ozone is one of the most powerful oxidizing equipment, so it is effectively used to kill bacteria, viruses, and fungi. Many industrial processes use ozone because ozone can run without forming a by-product in water. Nevertheless, the utilization of ozone in Indonesia has not been applied maximally, due to the large cost of commercial ozonator equipment and operational life that is relatively short. In addition, many still do not comprehensively comprehend the ozonation process that is relatively very fast in the presence of ozone conditions that can only last a few minutes before parsing back into oxygen. In this study, the DBD (Dielectric Barrier Discharge) plasma reactor model with parallel plates for ozone generation at room temperature was developed. Furthermore, this study is more focused on conducting performance tests and optimizing ozone productivity in parallel spacer corona discharge chambers. This designated ozonator was treated as a plasma reactor to perform various tests with varying feed flow rates, input voltages, and gas feeds (compressed air and medical oxygen). After the productivity of the ozonators were tested with iodometric titration method, the ozonator’s productivity in generating ozone and its optimum operating condition were obtained. It can produce up to 0.82 g ozone/h with compressed air feed and 6.45 g ozone/h with medical oxygen feed.

Factors Affecting the Presence of Adequately Iodized Salt at Home in Wolaita, Southern Ethiopia: Community Based Study.

Background Universal use of iodized salt is a simple and inexpensive method to prevent and eliminate iodine deficiency disorders like mental retardation. However, little is known about the level of adequately iodized salt consumption in the study area. Therefore, the study was aimed at assessing the proportion of households having adequately iodized salt and associated factors in Wolaita Sodo town and its peripheries, Southern Ethiopia. Methods A cross-sectional study was conducted from May 10 to 20, 2016, in 441 households in Sodo town and its peripheries. Samples were selected using the systematic sampling technique. An iodometric titration method (AOAC, 2000) was used to analyze the iodine content of the salt samples. Data entry and analysis were done using Epi Info version 3.5.1 and SPSS version 16, respectively. Result The female to male ratio of the respondents was 219. The mean age of the respondents was 30.2 (±7.3 SD). The proportion of households having adequately iodized salt was 37.7%, with 95% CI of 33.2% to 42.2%. Not exposing salt to sunlight with [OR: 3.75; 95% CI: 2.14, 6.57], higher monthly income [OR: 3.71; 95% CI: 1.97–7.01], and formal education of respondents with [OR: 1.75; 95% CI: 1.14, 2.70] were found associated with the presence of adequately iodized salt at home. Conclusion This study revealed low levels of households having adequately iodized salt in Wolaita Sodo town and its peripheries. The evidence here shows that there is a need to increase the supply of adequately iodized salt to meet the goal for monitoring progress towards sustainable elimination of IDD.

Prevalence of goiter and associated factors among pregnant mothers residing in a district with poor socioeconomic status in Rajasthan state, India.

Background:National survey documented that none of the Indian state is free from iodine deficiency (ID). Hence, the study was conducted with the objective to assess prevalence of goiter and associated factors among pregnant mothers (PMs) in a backward district of Indian state, Rajasthan.Methods:A cross-sectional survey was conducted during January to March 2015. Multistage random sampling was utilized to select PMs. A total of 1,183 villages were enlisted with their respective population, and 30 villages were selected using population proportionate to size sampling. Subjects were included from a cluster till the numbers reached to 17. PMs were clinically examined for goiter by palpation method. Casual urine (n = 226) and salt samples (n = 220), were collected from a subgroup of subjects, and iodine concentrations were analyzed by using wet digestion and iodometric titration methods, respectively.Results:The prevalence of goiter was found to be 14.2% (95% CI; 11.2–17.2). Goiter prevalence did not significantly differ with respect to trimesters of pregnancy (P = 0.09), iodine content in salt (P = 0.8), and urinary iodine concentrations (UIC, P = 0.69). The median UIC was 174 μg/L (IQR; 116–300 μg/L), which indicated adequate iodine intake. There was higher prevalence of goiter in PMs consuming salt with inadequate iodine than those with adequate, which was not significant (P = 0.8). Goiter prevalence was also insignificantly higher among PMs with UIC <150 μg/L than those with UIC ≥150 μg/L (P = 0.69).Conclusion:The study population is in transition phase from mild ID (goiter prevalence 14.1%) to sufficiency (median UIC 174 μg/L).

ЕФЕКТИВНІСТЬ КОНТРОЛЮ ЯКОСТІ ХАРЧОВИХ ПРОДУКТІВ МЕТОДОМ ТОНКОШАРОВОЇ ХРОМАТОГРАФІЇ

Urgency of the research. By high-quality and quantitative composition of components in food products it is possible to judge as far as they natural and safe, which composition of vitamins and microelements they have, what properties change during technological treatment. Target setting. It is known, that on maintenances of vitamin С considerably influence the method storage and their technological treatment. Therefore, for providing high-quality food it is constantly needed to control the quality standarts of products. For determination of high-quality and quantitative composition of food products is use the methods of gas-liquid, ion-exchange or liquid chromatography of high resolution. At the same time, little attention is paid to the use of thin-layer chromatography (TLC). Analysis of recent research and publications. Scientific publications show the promise of using the thin-layer chromatography method: to determine the concomitant simple sugars in pectin samples; when studying the chemical composition of pharmacological compounds and biological objects; when determining antibiotics in milk and animal meat. It is emphasized that one of the important stages in the analysis of organic substances is the mandatory confirmation of the obtained results by alternative analytical methods. Uninvestigatigated parts of general matters defining. The analysis of publications showed that thin-layer chromatography did not get wide distribution for applying at food products quality control. The research objective.. On the basis of thin-layer chromatography, as accessible exspres-method, to show efficiency food products quality control and changes which take place at storage and treatment. The statement of basic materials. With using of TLC method the stability of vitamin С was explored at heating and vinegar acid action (terms of canning), and also maintenances of vitamin С in food products which are used after their long term storage (lemon, apple, potato, beet) and can be the source of vitamin С in a winter-spring period. Researches, conducted by an iodometric method of titration showed satisfactory convergence with the results which got by TLC method. Conclusions. The expedience of thin-layer chromatography method using is shown for the high-quality and quantitative analysis of food products composition. A method differs by simplicity of implementation, low costing, and allows to explore different samples at the same time. TLC can be used as an express-method.

Iodine content of dietary salt at household level and associated factors using Iodometric titration methods in Dera District, Northwest Ethiopia

BackgroundIn developing countries most of the edible salts have insufficient iodine content; the problem is worse in Africa. Only 15.4% of the Ethiopian population was using adequately iodized salt. Several factors affect iodine content of edible salt including poor handling practices. The existing evidence isn’t sufficient to detail the specific factors at the household level. Therefore, the aim of this study was to determine the iodine content of edible salt and identify factors associated with salt iodine content in Dera District, Northwest Ethiopia.MethodsA community-based cross-sectional study was conducted among 1194 households. A multi-stage sampling technique was used to select the households, and data were collected using the interview. A 50 g salt sample was collected from each selected household and was shipped to the Ethiopian Food, Medicine and Health Care administration and Control Authority (EFMHACA) laboratory center for iodine level analysis. The samples were analyzed using titration method. Data were entered into EPI-INFO and analyzed in SPSS.ResultsOut of 1194 salt samples collected, 57.4% had iodine content in the range 15 ppm to 59.42 ppm. Salt stored in closed containers was more likely to have better iodine content compared to salt stored with open containers (AOR = 1.7, 95% CI: 1.24–2.42). Salt samples stored in dry places were 1.5 times more likely to retain iodine compared to samples stored near to heat/fire or in a moist area (AOR = 1.5, 95% CI: 1.03–2.14). Similarly, salt samples stored for less than 2 months were more likely to have adequate iodine level compared to samples stored for over 2 months (AOR = 1.6, 95% CI: 1.12–2.29).Salt samples obtained from household heads attended primary education (AOR = 1.5, 95% CI: 1.05–2.26), high school (AOR = 1.7, 95% CI: 1.05–2.64), and University (AOR = 2.8, 95% CI: 1.06–5.62) were more likely to have adequate iodine content in edible salt compared to whose didn’t attend formal education.ConclusionsNearly three out of five salt samples had enough iodine content. However, this level is low compared to the WHO recommendation (90%). The age, educational status of head of the household, duration of salt storage, use of cover to store salt and knowledge of household heads were associated with an iodine content of salt. Therefore, use of cover and proper storage of edible salt should be encouraged; improving the educational status of the community is essential the edible salt to retain its iodine content at the household level.

Analisis Umur Simpan Bubuk Kakao dalam Kemasan Plastik Standing Pounch Menggunakan Pendekatan Model Arrhenius

Cocoa powder is usually used to be a raw material in the chocolate products. In the large scale production, cocoa powder must be stored at specific time period before it was used. The quality of cocoa powder can decrease during storage period hence shelf life analysis of cocoa powder is needed. The aim of this study was to determine the shelf life of cocoa powder by Accelerated Shelf Life Testing (ASLT) Method with Arrhenius Model Approach. Cocoa powder was stored at different temperature (30, 40, and 50oC) and different packaging type (plastic with zipper and paper craft with zipper) to simul atedacceleration of damage as a result of temperature increase. Cocoa powder contained high level of fat so it more easily gone rancid. Moisture content and peroxide value were observed periodically that shown the quality parameters of cocoa powder. Initial moisture content and fat content of cocoa powder were analyzed by gravimetric method. Degree of rancidity which was shown with peroxide value was analyzed by iodometric titration method. According to the change of peroxide value, the shelf life of cocoa powder can be estimated.

The electrocatalysis of oxygen evolution reaction on La1−xCaxFeO3−δ perovskites in alkaline solution

The electrocatalytic oxygen evolution reaction (OER) on iron based perovskites with composition La1−xCaxFeO3−δ (0.0 ≤ x ≤ 1.0) in alkaline solution has been investigated. The perovskite samples were synthesized by combustion method. Energy dispersive spectroscopy and X-ray photoelectron spectroscopy were used to determine the bulk and the surface composition, respectively. The X-ray diffraction and iodometric titration method were employed to examine the phases and the oxidation state, respectively. It was observed that incorporation of calcium (Ca2+) ions in the lattice of LaFeO3 decreases the lattice parameters and the cell volume systematically as evaluated by Rietveld method. Furthermore, increase in the degree of Ca2+ substitution from 0.0 to 1.0, increases the average oxidation state of iron from Fe3+ to Fe4+ in addition to creating oxygen vacancies. The evaluation of OER kinetics on a rotating disk electrode setup suggests that incorporation of Ca2+ decreases the activity initially (0.0 ≤ x ≤ 0.4), but further substitution increases the activity. The maximum activity was observed for x = 1.0. This change in the OER activity suggests an interplay between the bond lengths and angles, oxygen vacancy and the average oxidation state of Fe.

Unsatisfactory results of the Tunisian universal salt iodization program on national iodine levels

Lack of iodine intake may promote a spectrum of disorders termed iodine deficiency disorders. Universal salt iodization laws were adopted in Tunisia to overcome this problem. This study examines the adequacy of iodized salt in the distribution chain two decades after its last assessment. A cross-sectional design was carried out in 2012 using the multi-stage cluster sampling technique. Salt samples from 24 governorates were collected at wholesaler level (n=635), retailer level (n=1440) and household level (n=1560), and analyzed using a validated iodometric titration method. Iodine concentration at each level of distribution chain was within the recommended range of 15–27mg/kg. Iodine content in household salt was significantly different according to the salt manufacturer and also between geographical regions (p <0.0001). Moreover, an insufficient coverage of adequately iodized salt consumption (less than 90%) was found with reference to international standards (≥15mg/kg). About 85.6% (95%CI: 78.3–90.8) of analyzed samples were adequately iodized at the intermediate levels of supply-chain (wholesalers and retailers). Our study demonstrates a decrease in the availability of iodized salt in households. It can thus be concluded that universal salt iodization legislation has not been sufficient to ensure an adequate supply of iodine in the population, and an evaluation system needs to be reactivated.

Phenotypic detection of extended –spectrum betalactamase production in Proteus. mirabilis isolation from Patients with Significant Bacteriuria in Najaf provina

250 mid-stream urine samples were collected from patients suspected of urinary tract infection (UTI) who were attended to Three hospitals (Medical Al-Sader City, Al-Hakeem, and Al-Zahra Maternity and Children) in Najaf provina during the period of October 2011 to January 2012 and screened for the presence of Proteus mirablis .The growth of ≥105 colony forming units/ml was considered as significant bacteriuria.&#x0D; A total of 198 (79.2%) significant bacteriuria were detected. The study showed higher incidence of UTI in females 129 (65.2%)than males 69 (34.8% )However , 52 (26.3%) isolates of Proteus mirabilis , 146 (73.7%) isolates other species pathogens. The 52 isolates of Proteus mirabilis were tested for their antibiotic resistance against 11 antibiotics by the Kirby-Bauer disk diffusion test. All the isolates were found to be resistant to at least 5 antibiotics to which they were subjected. Therefore, all these isolates were considered to be multidrug resistant. The majority 39 (75.0%) isolates of Proteus mirabilis were able to produce β-lactamase enzymes with rapid iodometric method. All isolates of Proteus mirabilis were tested for their ability to produce Extended-spectrum β-lactamase . The result showed that 18 (34.6%) isolates were able to produce ESBLs.

Determination of the oxidant activity of chlorinated water by chronoamperometry

A new version of the chronoamperometric method, adapted to the determination of the oxidative (oxidant) activity of a medium on an example of chlorinated water, was proposed. The supporting solution contained K4Fe(CN)6. By its oxidation with oxidants present in the sample, K3Fe(CN)6 formed; its reduction current served as an analytical signal. The current of K3Fe(CN)6 reduction was recorded at a potential of 0 V, selected from the cyclic voltammogram of the K3Fe(CN)6/K4Fe(CN)6 system in the range where the oxidized form of the reagent was reduced and the reduced form was stable. A gold electrode was the measuring electrode. The possibility of using a stable solution of K3Fe(CN)6 as a component of a standard addition and as a solution for plotting a calibration curve was demonstrated. The limit of detection of the amount of dissolved chlorine and products of its interaction with water is 8 × 10–6 M. The data obtained by the proposed procedure and by the iodometric methods correlate well with each other (r = 0.93–0.95). The proposed version of the chronoamperometric method can be used to monitor the amount of dissolved chlorine and products of its interaction with water in water supply systems, pools, and disinfecting solutions and to determine other water-soluble oxidants.

Investigation on the structural, magnetic and magnetocaloric properties of nanocrystalline Pr-deficient Pr1−xSrxMnO3−δ manganites

We have investigated the structural, magnetic and magnetocaloric properties of nanocrystalline Pr-deficient Pr1−xSrxMnO3−δ Perovskite manganites. Rietveld refinement of the X-ray powder diffraction patterns confirms that all the studied compounds have crystallized into an orthorhombic structure with Pbnm space group. Transmission electron microscopy analysis reveals nanocrystalline compounds with crystallite size less than 50nm. The selected area electron diffraction patterns reveal the highly crystalline nature of the compounds and energy dispersive X-ray spectroscopic analysis shows that the obtained compositions are nearly identical with the nominal one. The oxygen stoichiometry is estimated by iodometric titration method and stoichiometric compositions are confirmed by X-ray Fluorescence Spectrometry analysis. A large bifurcation is observed in the ZFC/FC curves and Arrott plots not show a linear relation but have a convex curvature nature. The temperature dependence of inverse magnetic susceptibility at higher temperature confirms the existence of ferromagnetic clusters. The experimental results reveal that the reduction of crystallite size to nano metric scale in Pr-deficient manganites adversely influences structural, magnetic and magnetocaloric properties as compared to its bulk counterparts reported earlier.

Comparison of Three Independent Methods of Cephalexin Determination by Means of Potassium Caroate

Aims.Three different assays for the quantity determination of Cephalexin in pure substance were developed and compared using potassium caroate as analytical reagent. Materials and Methods. Cephalexin pure substance was used and analytical reaction by means of KHSO5 as an oxidant was studied. Voltammetric, kinetic-spectrophotometric and iodometric methods were developed and validated. Results. The chemical reaction is finished with formation of the S-oxide of Cephalexin in the iodometric and voltammetric methods and the S-oxide hydrolysis product in the kinetic-spectrophotometric method. The reaction finishes in 1 min (observation time). The methods have been validated and good results including precision, accuracy and recovery were obtained. The recovery percent ranged from 98.7 to 101.4%, RSD from 1.42 to 3.0%. The methods proposed are linear in a wide range: voltammetry 2-45 µg mL-1, kinetic-spectrophotometry 1-16 µg mL-1, and iodometry 0.05-0.35 mg mL-1. LOD and LOQ were calculated. The kinetic-spectrophotometric method is the most sensitive (LOQ=1.0 µg mL-1). Conclusions. The methods proposed are rapid, simple and inexpensive and could be applied to pharmaceutical preparation.

REACTION KINETICS OF OZONE GAS IN WHEAT FLOUR

The implementation of the ozonation process in milling industry requires understanding of the behavior of this gas in wheat flour. Therefore, this study aimed to investigate the reaction kinetics of ozone gas in wheat flour. Wheat flour ozonation at 0.54; 1.07; 1.61 and 2.14 mg L-1 concentrations was performed on a prototype that consists of a cylinder and a mixing system with helical thread. The iodometric titration method was used to quantify the ozone concentration in the air stream. The reaction kinetics was characterized by determining the saturation time and decomposition kinetics (decay rate and half-life time). With increasing ozone concentration, less time was required to saturate the wheat flour. Saturation times were 812, 434, 370 and 342 min for ozone concentrations of 0.54, 1.07, 1.61 and 2.14 mg L-1 respectively. Increased ozone concentration did not influence the constant decay rate and half-life time. The kinetics for ozone decomposition could be represented as a first order model, in which the decay rate constant was 0.23±0.008 min-1 and half-life time was 3.02±0.081 min.

Determination of Relative Rate Constants for Reactions of 2,2’-Azobis-(2-Amidinopropane) Dihydrochloride Peroxyl Radicals with Dihydroxybenzenes and Their Derivatives

An iodometric method for determining the antiradical activity (ARA) of dihydroxybenzenes in the reaction with 2,2′-azobis-(2-amidinopropane) (AAP) peroxyl radicals (rOO• ) in conditions close to those obtaining in biological systems was developed. A means of calculating relative rate constants of reactions of phenols with rOO• from the kinetics of consumption of an inhibitor added at low concentration was proposed. The greatest levels of ARA were seen with resorcinol, orcinol, and hydroquinone, which are able to dissociate to form highly reactive mono-and bianionic forms of phenolate ions. A method of calculating relative rate constants of these reactions was proposed, based on the AAP - AAP peroxyl radical - phenol kinetic model.

An HPLC method for the detection of hydro peroxides derived from linalyl acetate in citrus oils, using post‐column luminol‐mediated chemiluminescence detection

AbstractLinalyl acetate is an unsaturated terpene commonly found in many essential oils, and it is easily oxidized by atmospheric oxygen to form hydroperoxides. The hydroperoxides of linalyl acetate are known to be sensitizers capable of causing allergic contact dermatitis. The standard iodometric titration methods (peroxide value [POV] methods) typically used to measure hydroperoxide levels in essential oils provide only a total level of all oxidizing species, including hydroperoxides. These POV methods are not capable of species differentiation and therefore may not reliably correlate well with the dermatological sensitizing potency of a particular sample. This laboratory has previously reported a high‐performance liquid chromatographic method using a post‐column chemiluminescent reaction to detect hydroperoxides derived from limonene and linalool. Herein we report that this same method is also useful for the detection of hydroperoxides derived from linalyl acetate.

Определение относительных констант скоростей реакции пероксильных радикалов дигидрохлорида 2,2’-азобис-(2-амидинопропана) с диоксибензолами и их производными

Усовершенствована йодометрическая методика определения антирадикальной активности (АРА) диоксибензолов в реакции с пероксирадикалами 2,2’-азобис-(2-амидинопропана) (ААП) (rOO•) в условиях, близких к биологическим системам. Предложен способ расчета относительных констант скоростей реакции фенолов с rOO• по кинетике расходования ингибитора, введенного в малой концентрации. Установлено, что наибольшей АРА обладают резорцин, орцин и гидрохинон, которые способны диссоциировать с образованием высокореакционноспособных моно- и бианионных форм фенолят-ионов. Предложен метод расчета относительных констант скоростей изученной реакции, основанный на кинетической модели ААП — пероксирадикал ААП — фенол.

On the Comparison of Stability of YBa\(_2\)Cu\(_{3-x}\)Zn\(_x\)O\(_{7-\delta}\), YBa\(_{2-x}\)Sr\(_x\)Cu\(_3\)O\(_{7-\delta}\) and YBa\(_2\)Cu\(_{3-x}\)Al\(_x\)O\(_{7-\delta}\) in Water for Various Concentration of Zn \((0&lt;X&lt;0.1)\), Sr \((0 &lt; x &lt; 0.6)\)

Substitutional study of Zn on YBa\(_2\)Cu\(_{3-x}\)Zn\(_x\)O\(_{7-\delta}\) \((0 &lt; x &lt; 0.1)\) have been carried out on polycrystalline samples to determine the effect of Zn doping in small concentration on the instability of the unit cell structure in the presence of water. YBa\(_{2-x}\)Sr\(_x\)Cu\(_{3}\)O\(_{7-\delta}\) and YBa\(_2\)Cu\(_{3-x}\)Al\(_x\)O\(_{7-\delta}\) polycrystalline samples for various concentration of Sr\((0 &lt; x &lt; 0.6)\) and Al\((0 &lt; x &lt; 0.6)\) have also been treated with water. The degree of degradation in the substituted samples is a function of the type of the dopant Sr\(^{2+}\)/Al\(^{3+}\)/Zn\(^{2+}\) as well as the molar concentration of the dopant. The degradation is found to be minimum in the case of Sr\(^{2+}\) substitution at Ba\(^{2+}\) sites in YBa\(_2\)Cu\(_3\)O\(_{7-\delta}\) as compared to the degradation of Al\(^{3+}\) and Zn\(^{2+}\) substitution at Cu\((1)\) and Cu\((2)\) sites, respectively. The degradation is maximum in the case of Zn\(^{2+}\) substitution at Cu\((2)\) site. The studies were made using R-T measurements, X-ray diffraction technique and iodometric titration method and SEM.

Comparison of three different methods to detect the production of ?-lactamase enzyme by staphylococci

Production ?-lactamase enzyme is the most common and important mode of exhibiting resistance to ?-lactam antibiotics. Manifestation of this enzyme is difficult to demonstrate in routine antibiotic sensitivity testing. Sensitivity to penicillin is not sufficient to indicate whether this antibiotic should be used clinically and main factor compromising the clinical efficacy of these drugs is the production of ?-lactamase enzyme. Only feasible method for determination of ?-lactam resistance is to demonstrate the physical presence of enzyme. Three different methods (acidometric method, iodometric method and chromogenic cephalosporin method) are available for this. The objective of present study is to compare these 3 method to detect the production of ?-lactamase enzyme in staphylococci isolated from various clinical samples. Susceptibility to penicillin, oxacillin and vancomycin was also determined. Out of total 150 isolates, 114(76%) shows ?-lactamase production by chromogenic cephalosporin method, 110(73.3%) by iodometric method and 108(72%) by acidometric method. Penicillin and oxacillin resistance was 74.6% and 53.3% respectively. All isolates are sensitive to vancomycin. Out of three different methods used, chromogenic cephalosporin method is more sensitive (76%) than iodometric method (73.3%) and acidometric method (72%). Results also correlates with penicillin sensitivity in ABST except 2 isolates which shows ?-lactamase production by chromogenic cephalosporin method but remains penicillin sensitive in disc diffusion method. In case of agar diffusion tests, there is often insufficient ?-lactamase production from the test organism before an inhibitory concentration of antibiotic has diffused from the disc. Only ABST can lead to therapeutic failure sometimes.

Iodometric and Molecular Detection of ESBL Production Among Clinical Isolates of E. coli Fingerprinted by ERIC-PCR: The First Egyptian Report Declares the Emergence of E. coli O25b-ST131clone Harboring blaGES.

The extensive use of β-lactam antibiotics has led to emergence and spread of extended-spectrum β-lactamases (ESBLs). This study was conducted to investigate the prevalence of 7 different ESBL genes (blaTEM, blaSHV, blaCTX-M, blaVEB, blaPER, blaGES, and blaOXA-10) and O25b-ST131 high-risk clone among 61 clinical isolates of Escherichia coli. Also, one broad-spectrum β-lactamase (blaOXA-1) was investigated. This study was also constructed to evaluate iodometric overlay method in detection of ESBL production. Phenotypic identification of E. coli isolates using API 20E revealed 18 distinct biotypes. DNA fingerprinting using enterobacterial repetitive intergenic consensus polymerase chain reaction (ERIC-PCR) differentiated all isolates into 2 main phylogenetic groups with 60 distinct genetic profiles. Elevated values of minimal inhibitory concentration (MIC)50 and MIC90 for third- and fourth-generation cephalosporins were observed. Phenotypic tests revealed that 85.24% of isolates were ESBL producers. The incidence rates of blaTEM, blaSHV, blaCTX-M, blaGES, blaOXA-1, and blaOXA-10 among E. coli ESBL producer phenotype were 69.23%, 25%, 96.15%, 3.85%, 11.54%, and 48%, respectively. On the other hand, blaVEB and blaPER were not detected. Sequencing of blaTEM and blaSHV revealed that blaTEM-214 and blaSHV-11 were the most prevalent variants. Group characterization of blaCTX-M revealed that blaCTX-M-1 was the most prevalent group of blaCTX-M family. It was found that 30.77% of E. coli ESBL producers belonged to O25b-ST131 clone harboring blaCTX-M-15. This study concluded that iodometric overlay method was 100% sensitive in detection of ESBL production. To our knowledge, this is the first Egyptian study that declares the emergence of E. coli O25b-ST131 harboring blaGES.