magistrsko delo
Veronika Ana Kralj (Author), Tjaša Danevčič (Reviewer), Jerneja Ambrožič (Mentor)

Abstract

V Sloveniji vključuje monitoring naravnih kopalnih voda le kvantifikacijo koliformnih bakterij in enterokokov. Analiza fenotipskih in genotipskih lastnosti je pogosto ključna za ovrednotenje potencialne patogenosti sevov, bremena genov povezanih z odpornostjo proti protimikrobnim učinkovinam v naravnih vodah in za ugotavljanje potencialnega vira onesnaženja. V okviru magistrskega dela smo raziskali prisotnost genov za dejavnike virulence in odpornost proti sedmim protimikrobnim učinkovinam pri sevih vrste E. coli, izoliranih iz vzorcev vode in sedimentov, odvzetih enkrat mesečno na 4 vzorčnih mestih, v obdobju enega leta. Na podlagi rezultatov, dobljenih z metodo ERIC-PCR, smo iz analize izločili sorodne/klonalne izolate, ki smo jih pridobili na isti lokaciji vzorčenja isti dan. V končno analizo je bilo tako vključenih 62 sevov, ki smo jih uvrstili v filogenetske skupine po Clermontu in z metodo PCR preverili prisotnost 27 genov, povezanih z dejavniki virulence. Pri izbranih sevih smo preverili fenotipsko odpornost proti nekaterim protimikrobnim učinkovinam, genotipsko za β-laktamaze iz skupin TEM, SHV, OXA in CTX-M ter plazmidno zapisano odpornost proti fluorokinolonom (PMQR). Naši rezultati nakazujejo, da so sevi E. coli, prisotni v kopalnih vodah, zelo raznoliki, od potencialno patogenih in večkratno odpornih do občutljivih, brez ključnih dejavnikov virulence. Večkratno odporni, CTX-M pozitivni sevi, in sevi z največ genov za dejavnike virulence, so bili izolirani v februarju, aprilu in juniju v vzorcih vode iz Olimpijskega veslaškega centra ter kopališča v Mali Zaki na Blejskem jezeru. Potencialni vir onesnaženja, glede na genotip izolatov, čas izolacije in mesto vzorčenja, je najverjetneje kmetijska dejavnost.

Keywords

mikrobiologija vode;okoljski bakterijski sevi;Escherichia coli;odpornost proti protimikrobnim učinkovinam;naravne kopalne vode;geni za dejavnike virulence;

Data

Language: Slovenian
Year of publishing:
Typology: 2.09 - Master's Thesis
Organization: UL BF - Biotechnical Faculty
Publisher: [V. A. Kralj]
UDC: 579.68:579.25/.26:577.2.083
COBISS: 150523139 Link will open in a new window
Views: 17
Downloads: 12
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Other data

Secondary language: English
Secondary title: Virulence factor genes and antimicrobial resistance of Escherichia coli isolated from natural bathing waters
Secondary abstract: Monitoring of natural bathing waters in Slovenia includes the quantification of coliform bacteria and enterococci. Analysis of phenotypic and genotypic traits can be crucial to assess the potential pathogenicity of strains, the gene load associated with antimicrobial resistance in environmental waters and to identify the potential source of pollution. In the master thesis, we studied the occurrence of virulence genes and resistance to seven antimicrobial substances in E. coli strains in samples, isolated from waters and sediments, sampled monthly over a period of one year at 4 different locations. With ERIC-PCR method, we excluded clonal/related isolates from the same location on the same sampling day. In our analysis, we included 62 strains, which were classified into phylogenetic groups determined by Clermont, and the presence of 27 genes related to virulence factors was determined by the PCR method. The selected strains were tested for resistance to selected antimicrobial agents using the phenotypic method and genotyping for β-lactamases from the TEM, SHV, OXA and CTX-M groups, as well as plasmid-encoded resistance to fluoroquinolones (PMQR). Our results show that the E. coli strains present in bathing waters are very diverse, from potentially pathogenic and multi- resistant to susceptible to antimicrobial substances without the presence of key virulence factors. Multiple resistant CTX-M positive strains and strains with the presence of several genes for virulence factors were isolated in the water samples of the Olympic rowing centre and the bathing area at Mala Zaka of Lake Bled in February, April and June. A potential pollution source, according to the phylogeny of isolates, time and location of sampling, is agricultural activity.
Secondary keywords: water microbiology;environmental bacterial strains;Escherichia coli;resistance to antimicrobials;natural bathing waters;virulence factor genes;
Type (COBISS): Master's thesis/paper
Study programme: 0
Thesis comment: Univ. v Ljubljani, Biotehniška fak., Oddelek za mikrobiologijo
Pages: 1 spletni vir (1 datoteka PDF (XIII, 67 str., [4] f. pril.))
ID: 18721671