Browsing by Subject "Antibioottiresistenssi"

Aggregatibacter actinomycetemcomitans aiheuttaa aggressiivista parodontiittia ja levitessään vaikeita infektioita myös muualla elimistössä. Kyseessä on erittäin virulentti bakteeri, jonka aiheuttamien infektioiden hoito pitää sisällään antimikrobilääkityksen lisäksi mekaanisen puhdistuksen. Antibiooteille vastustuskykyisten bakteerikantojen kehittyminen ja leviäminen on vakava maailmanlaajuinen ongelma, joka koskee myös A. actinomycetemcomitansia. Enterococcus faecalis kestää useita antibiootteja joko luonnostaan tai resistenttien kantojen kehittymisen ansiosta. E. faecalis aiheuttaa esimerkiksi virtsatieinfektioita, sepsistä, endokardiittia ja meningiittiä. Bakteriofageja on käytetty pitkään bakteeriperäisten infektioiden hoidossa ja niillä on useita etuja verrattaessa antimikrobilääkkeisiin. Tämän tutkimuksen tarkoituksena on löytää laboratoriokokein A. actinomycetemcomitans -infektioiden hoitoon sopivia bakteriofageja jätevesi- ja sylkinäytteistä sekä kaupallisesta faagicocktailista ja tutkia E.faecaliksen faagien isäntäkirjoa BioScreen-laitteiston avulla. Tutkimuksen aineistona toimi parodontiittipotilaiden ientaskuista kerätyt A. actinomycetemcomitans-näytteet, eri puolilta Suomea kerätyt jätevesinäytteet ja kaupallinen faagiseos Fagodent. E. faecaliksen isäntäkirjomäärityksessä käytettiin faagihoitoryhmän E. faecalis-kantoja ja faageja. A. actinomycetemcomitansin kasvatus osoittautui haasteelliseksi bakteerin kertymiä muodostavan kasvutavan vuoksi. Tutkimuksessa ei havaittu lyyttisiä faageja kyseisille A.actinomycetemcomitans-kannoille. Tutkimuksessa onnistuttiin löytämään optimaaliset olosuhteet E. faecaliksen faagien toiminnalle.

The development of new antibiotics is very challenging work. However, it has become less attractive area of research for the pharmaceutical industry due to the rapid development of antibiotic resistance among bacteria. As a result, nowadays there are less new antimicrobial medicines appearing on the market. Increase in antibiotic resistance challenges the effective treatment of infectious diseases. Therefore, it is important to know about the existence and prevalence of antibiotic resistant bacteria and resistance genes. Waste water has been found to contain substantial amounts of antibiotics or their derivatives. Furthermore the bacterial density of the waste water is high. These factors may cause the selection pressure that assists the evolution, preservation and spread of antibiotic resistance in bacterial population. Wastewater treatment plants are believed to act as a reservoir of antibiotic resistant bacteria and antibiotic resistance genes. In this study, from samples taken from Viikinmäki wastewater treatment plant it was determined the quantity of resistance genes making bacteria resistance to a wide range of beta-lactam antibiotics. The samples were taken at the different stages of wastewater treatment process during three sampling days in June, September and December 2010. The samples were taken from the incoming wastewater and, from the final effluent and from the dried sludge. The DNA from wastewaters and sludge was isolated and the gene copy numbers of blaCTX-M-32 and blaOXA-58 antibiotic resistance genes were measured by quantitative PCR method. Antibiotic resistance gene copy numbers were normalized with 16S ribosomal RNA gene copy numbers. The antibiotic resistance genes investigated in this work make bacteria resistant to broad-spectrum penicillins, different groups of cephalosporins, monobactams, and carbapenems. It was found that blaOXA-58 and blaCTX-M-32 gene copies do exist in both incoming wastewater and dried sludge. From the incoming wastewater we found on average 3x10-3 blaOXA-58 gene copies/16S rRNA gene and 7x10-5 blaCTX-M-32 gene copies/16S rRNA gene. From dried sludge we found on average 3x10-3- blaOXA-58 gene copies/16S rRNA gene and 2x10-2 blaCTX-M-32 gene copies/16S rRNA. Both antibiotic resistance genes were also found in the final effluents. The amounts of antibiotic resistance genes /16S rRNA genes were found to decrease during of the wastewater treatment. In the final effluent the amount of blaOXA-58 genes was found to be two orders of magnitude less than in the incoming wastewater and for, blaCTX-M-32 gene copies it was found the decrease by one order of magnitude. Although the amount of antibiotic resistance genes decreased during of the wastewater treatment, the amount left in the final effluent is still notable and when it ends up in the water or soil it might have an effect to the antibiotic resistance in the nature.

The emergence of antibiotic resistance is a growing concern globally. The horizontal spread of antimicrobial resistance genes (ARG) causes multi drug resistant strains that can be harmful to human- and animal health. This risk must be considered when new bacterial strains are used in the plant protection industry, therefore this master’s thesis presents a new bioinformatical method to evaluate the potential of ARG to horizontally transfer to another bacteria. This thesis will walk through analyses that can be used to hunt for ARGs and mobile genetic elements (MGE) in bacterial whole genome sequence data. Also, this thesis presents a new computational analysis tool called MGEradar that reveals MGEs that are linked to a specific ARG. Also, this thesis presents a simple metod for studying the prevalence of an ARG among other bacterial strains of the suspect species. MGEradar, the prevalence analysis and the bioinformatical pipeline can be helpful tools to evaluate the intrinsicness and mobility of an ARG. For the evaluation of the bioinformatical method, the genomes of Escherichia coli and Bacillus thuringiensis are examined to determine the MGEs associated with two ARGs, mcr-1 and fosB.