Mihai Nita-Lazar

STUDY OF BACTERIA RESISTANCE MECHANISMS IN RESPONSE TO A STRESS INDUCED BY PHARMACEUTICALS COMPOUNDS

Three pharmaceutical compounds (Trimethoprim, Carbamazepine and Benzethonium chloride) were investigated to unveil possible toxic effects on two bacterial strains (Citrobacter freundii and Comamonas testosteroni). The pharmaceutical compounds stress triggered a bacterial defence mechanism which was evaluated at transcriptional and translational levels. In this study, potential bacterial biomarkers induced by the pharmaceutical stress were unraveled.

VARIATION OF ANIONIC AND NONIONIC SURFACTANTS PRESENCE IN WASTEWATERS

It has been known the surfactants have been used to remove stains from leather, clothes and household items, particularly from kitchens and bathrooms. Our studies were carried out during eight months in order to include all the seasons (July, August 2016 – Summer; September, October 2016 – Autumn; January, February 2017 – Winter and March, April 2017 – Spring) to detect the variation of anionic and nonionic surfactants concentration from industrial wastewaters. The wastewater samples were taken from three sampling points belonging to a subway maintenance company: Berceni, Militari and Pantelimon. The total concentration of anionic surfactants in wastewaters was analyzed by Methylene Blue Active Substances Method (MBAS), and the total concentration of nonionic surfactants was detected by the method with Dragendorff reagent. The results showed that anionic and nonionic surfactants concentrations detected in wastewater samples were less than 0.1 mg/L (under the quantification limit) up to 2.03 mg/L for anionic surfactants and the nonionic surfactants had less than 0.15mg/L (under the quantification limit) up to 1.72 mg/L. According to the national legislation (HG 352/2005, NTPA 002, Annex 2/2005), the accepted value of surfactants (as sum of anionic and nonionic) is less than 25 mg/L. The results of the study revealed the highest concentration of both anionic and nonionic surfactants during March, one of the possibilities of this variations could be the lower level of maintenance in February than the other months. Furthermore, this change of concentration may be the result of switching the type of organic compound (detergent) using for the subways cleaning.

ENVIRONMENTAL FACTORS – POTENTIAL RESERVOIRS OF NOSOCOMIAL INFECTIONS

All infections follow the basic epidemiological pattern that if recognized early helps to apply the measures to prevent and control pathologies. The epidemiological process cannot be triggered in the absence of the microorganism’s reservoir and therefore it is very important to control the potential reservoirs involved in nosocomial infections. The etiological structure of nosocomial infections varies and includes a wide variety of potentially or strictly pathogenic bacteria that have native or acquired proprieties of virulence and antibiotic resistance. The aim of this project was to monitor the potential role of the environmental risk factors involved in outbreak nosocomial infections. The microbiological studies from an emergency hospital from Bucharest have been started in January 2016 and samples were quarterly collected from drilling and tap water, waste water, air and surfaces. There were performed quantitative analyzes of microbiological contamination level and qualitative analyzes for pathogenic and resistant bacteria detection. Some pathogenic bacteria have been identified in the waste water and drilling water, indicating their interference. The antibiotic resistance properties were observed especially in bacteria from waste waters. Bacteria from vegetables from food preparation were detected in air samples and surfaces tests from kitchen. The results indicated that environmental factors from a medical unit could constitute a reservoir of microorganisms that can trigger nosocomial infections.