PRESENCE OF RESISTANCE IN CAMPYLOBACTER JEJUNI AND CAMPYLOBACTER COLI

There are 18 species belonging to the genus of Campylobacter (rRNK group I), of which thermophilic ones are the following: Campylobacter jejuni, Campylobacter coli, Campylobacter lari and Campylobacter upsaliensis. The aim of our research was to determine the sensitivity of Campylobacter species, isolated from human feces, to antibiotics being used in practice. The study involved 50 human strains of C. jejuni/coli isolated from feces in the Center for Microbiology in the Public Health Institute Nis. Sensitivity was tested by applying the disk diffusion method on seven antibiotics (erythromycin, gentamicin, tetracycline, ciprofloxacin, hloramphenicol, cephalexin and nalidixic acid). Our results showed low resistance to erythromycin, gentamicin and tetracycline (2%), which corresponds to the studies conducted in the world. Moreover, these findings indicate that erythromycin may be considered the drug of choice in the treatment of Campylobacter diarrhea in this region. Resistance to fluoroquinolone and nalidixic acid was 44%, and C. coli showed higher resistance compared to C. jejuni, though statistical significance was not proved

Antimicrobial susceptibility profiles of thermophilic campylobacters isolated from patients in the town of Niš

Background/Aim. In some clinical forms of human Campylobacter infections, such as prolonged diarrhea or associated with postinfections sequels, antibacterial treatment is necessary. The aim of the present study was to evaluate the antimicrobial susceptibility of thermophilic Campylobacter strains isolated from patients with diarrhea, as well as from patients with diarrhea followed by postinfections sequels, to drugs used in the therapy of enterocolitis, and to nalidixic acid used in laboratory identification and differentiation of thermophilic Campylobacter spp. Methods. We studied the antimicrobial susceptibility profiles of 131 Campylobacter strains isolated from patients with diarrhea (122 strains), diarrhea associated with rheumatic disorders (8 strains), and one strain isolated from a patient with Guillain-Barré Syndrome following Campylobacter enterocolitis. Susceptibility testing to erythromycin, gentamicin, tetracycline, chloramphenicol, ciprofloxacin and nalidixic acid was performed by the agar dilution method. Results. In the strains we investigated, resistance to gentamicin and chloramphenicol was not recorded, whereas a low rate of strains resistant to erythromycin (2.4%), a higher prevalence of strains resistant to tetracycline (9.9%), and a high level of resistance to ciprofloxacin (29.8%) and nalidixic acid (33.3%) were registered. All strains resistant to nalidixic acid were also resistant to ciprofloxacin. In addition, there was no difference in the occurrence of resistance between strains isolated from patients with diarrhea as compared to those isolated from patients with diarrhea followed by postinfection disorders. Conclusion. The fact that the most of Campylobacter strains were sensitive to erythromycin and all to gentamicin, makes erythromycin an antibiotic of choice in the treatment of Campylobacter diarrhea and gentamicin when parenteral therapy should be administered. Resistance to tetracycline and, especially, ciprofloxacin, necessitates antibiotic susceptibility testing

Impact of the process of polymerization of polyol and toluen diisocyanate on the environoment

The aim of this study was to investigate the impact of the process of polymerization of polyiol and tolyendiisocyanate on the environoment. Toluene diisocyanates are important industryal intermediates used in conjunction with polyether and polyester polyols as coreactants polyurethane foams, paints, varnishes, elasomers and coatings. This presentation summarizes existing information on the release and behavior of the process of polymerization of polyol and toluen diisocyanate on the environment. A major reaction of TDI in the environoment is formation of solid inert polyureas from reaction with water. In use, TDI is reacted with polyols to form many different polyurethane products. Polyurethanes have been show to be stable in the environment and in disposal have no adverse impact on municipal waste handling processes, landfills or incineration.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Influence of different carbon monolith preparation parameters on pesticide adsorption

The capacity of carbon monolith for pesticide removal from water, and the mechanism of pesticide interaction with carbon surface were examined. Different carbon monolith samples were obtained by varying the carbonization and activation parameters. In order to examine the role of surface oxygen groups in pesticide adsorption, carbon monolith surface was functionalized by chemical treatment in HNO3, H2O2 and KOH. The surface properties of the obtained samples were investigated by BET surface area, pore size distribution and temperature-programmed desorption. Adsorption of pesticides from aqueous solution onto activated carbon monolith samples was studied by using five pesticides belonging to different chemical groups (acetamiprid, dimethoate, nicosulfuron, carbofuran and atrazine). Presented results show that higher temperature of carbonization and the amount of activating agent allow obtaining microporous carbon monolith with higher amount of surface functional groups. Adsorption properties of the activated carbon monolith were more readily affected by the amount of the surface functional groups than by specific surface area. Results obtained by carbon monolith functionalisation showed that π-π interactions were the main force for adsorption of pesticides with aromatic structure, while acidic groups play an important role in adsorption of pesticides with no aromatic ring in the chemical structure

Corrosion behavior of the as-cast and heat-treated ZA27 alloy

Corrosion behaviour of the as-cast and heat-treated ZA27 alloy was examined. The alloy was prepared by conventional melting and casting route and then thermally processed by applying T4 heat treatment regime (solutionizing at 370 °C for 3 hours followed by water quenching and natural aging). Corrosion rate of the as-cast and heat-treated ZA27 alloy was determined in 3.5 wt. % NaCl solution through immersion test using both weight loss method and polarization resistance measurements. It was shown that applied thermal treatment resulted in increased ductility of the heat-treated alloy and had a small beneficial effect on the corrosion resistance of ZA27 alloy

Corrosion behavior of compocasted ZA27/SiCp composites in sodium chloride solution

The corrosion behavior of particulate ZA27/SiCp composites in an aerated sodium chloride solution was studied. The composites were synthesized via compocasting with addition of 1, 3 and 5 wt.% SiC particles in the matrix alloy. Composite samples were immersed for 30 days in the 3.5 wt.% NaCl solution open to the atmospheric air. Surface appearance and microstructure of the composites were examined by means of optical microscopy and scanning electron microscopy, while corrosion rates of the composites were determined using the weight loss method. It was revealed that SiC particles were not influenced by corrosion. General uniform corrosion occurred in the composite matrices, mainly in the region of the η phase. Local corrosion was noticed in micro-cracks and near clusters of particulate reinforcements. Results of microstructural examinations and immersion test indicate a slightly lower corrosion resistance of the ZA27/SiCp composites compared to that of the matrix alloy

Corrosion behavior of the as-cast and heat-treated ZA27 alloy

Corrosion behaviour of the as-cast and heat-treated ZA27 alloy was examined. The alloy was prepared by conventional melting and casting route and then thermally processed by applying T4 heat treatment regime (solutionizing at 370 °C for 3 hours followed by water quenching and natural aging). Corrosion rate of the as-cast and heat-treated ZA27 alloy was determined in 3.5 wt. % NaCl solution through immersion test using both weight loss method and polarization resistance measurements. It was shown that applied thermal treatment resulted in increased ductility of the heat-treated alloy and had a small beneficial effect on the corrosion resistance of ZA27 alloy

The influence of corrosion on the microstructure of thermally treated ZA27/SiCp composites

The influence of corrosion on the microstructure of ZA27/SiCp composites was examined. The composites were produced by compo casting technique and then subjected to the thermal treatment (T4 regime). Microstructural examinations were performed after 30-day exposure of thermally treated composites in the sodium-chloride solution. Corrosion processes have occurred in the composite matrix. Corrosion did not affect SiC particles in the composites. The local progress of corrosion in depth of the composite matrix was noticed in micro-cracks. Corrosion resistance of ZA27/SiCp composites was evaluated based on the mass loss of composite samples during the immersion test. It was found that corrosion resistance of the composites decreased with increase in content of SiC particles. The applied thermal treatment had a negative influence on the corrosion resistance of ZA27/SiCp composites

Corrosion behavior of compocasted ZA27/SiCp composites in sodium chloride solution

The corrosion behavior of particulate ZA27/SiCp composites in an aerated sodium chloride solution was studied. The composites were synthesized via compocasting with addition of 1, 3 and 5 wt.% SiC particles in the matrix alloy. Composite samples were immersed for 30 days in the 3.5 wt.% NaCl solution open to the atmospheric air. Surface appearance and microstructure of the composites were examined by means of optical microscopy and scanning electron microscopy, while corrosion rates of the composites were determined using the weight loss method. It was revealed that SiC particles were not influenced by corrosion. General uniform corrosion occurred in the composite matrices, mainly in the region of the η phase. Local corrosion was noticed in micro-cracks and near clusters of particulate reinforcements. Results of microstructural examinations and immersion test indicate a slightly lower corrosion resistance of the ZA27/SiCp composites compared to that of the matrix alloy