Karakterizacija oksacilin-hidrolizirajućih karbapenemaza u izolatima Acinetobacter baumannii iz Bosne i Hercegovine

master's thesis

• Title (english): Charecterization of carbapenem-hydrolyzing oxacillinases in Acinetobacter baumannii from Bosnia and Herzegovina
• Author: Domagoj Slačanac
• Mentor: Branka Bedenić (mentor)
• Committee member: Nataša Beader (predsjednik povjerenstva)
• Committee member: Goran Tešović (član povjerenstva)
• Committee member: Branka Bedenić (član povjerenstva)
• Granter: University of Zagreb; School of Medicine; (Department of Medical Microbiology and Parasitology); Zagreb
• Defense date and country: 2018-07-13, Croatia
• Scientific / art field, discipline and subdiscipline: BIOMEDICINE AND HEALTHCARE; Clinical Medical Sciences; Medical Microbiology

Abstract

Ovim su diplomskim radom prikazane oksacilinaze prisutne u vrsti Acinetobacter baumannii iz kliničkih izolata u Bosni i Hercegovini. Cilj je rada bio utvrditi fenotip rezistencije na antibiotike, tipove karbapenemaza i genotipove izolata A.baumannii prikupljenih iz Univerzitetske klinike u Mostaru. Načini na koji vrste roda Acinetobacter najčešće stječu rezistenciju na karbapeneme su produkcija β-laktamaza (enzima koji razgrađuju beta laktamski prsten), smanjena permeabilnost ili alteracija u proteinima koji vežu peniciline. Oksacilinaze su enzimi koji hidroliziraju β-laktamske antibiotike. Po Amblerovoj molekularnoj
klasifikaciji koja β-laktamaze dijeli u četiri skupine, oksacilinaze pripadaju grupi D. U testiranim izolatima utvrđene oksacilinaze uzrokuju rezistenciju acinetobactera na karbapeneme i uobičajeno se označuju kraticom CHDL. Oksacilinaze roda Acinetobacter se dijele u 5 filogenetskih grupa i označuju kraticom OXA: intrinzični enzimi nalik na OXA-51 i stečeni enzimi OXA-23, OXA-24/40, OXA-58, OXA-143, OXA-235. Enzimi iz grupe OXA-51 β-laktamaza su normalno prisutni u vrsti A.baumannii no kada se insercijska sekvenca ISAba1 nalazi ispred gena dolazi do povećane ekspresije gena za navedenu grupu enzima. Prisutne oksacilinaze su bile intrinzična OXA-51 te plazmidne OXA-23 i OXA-24/40 oksacilinaze. Bosna i Hercegovina je regija sa značajnim geografskim i populacijskim varijacijama te je značajna molekularna karakterizacija i tipiziranje izolata. Time se identificiraju izvori i načini prijenosa sojeva te planiraju buduće strategije kontrole infekcija što je od epidemiološkog značaja. Utvrđeno je da su izolati pozitivni na OXA-24/40 bili klonski srodni.

Abstract (english)

Oxacillinases from clinical isolates of Acinetobacter baumannii from Bosnia and Herzegovina are presented in this study. The aim of the study was to determine the resistance phenotype mechanisms of carbapenem resistance and genotypes of A.baumannii isolates from the University Clinic in Mostar. Species from the genus Acinetobacter are known as causative agents of nosocomial infections among immunocompromised patients as well as among those with severe underlying diseases. Their growing resistance to antibiotics is of great concern. Modes of acquiring resistance to β-lactam antibiotics are impaired permeability, alteration in penicillin-binding proteins, and β-lactamase mediated resistance, the most common mechanism. Carbapenem-hydrolysing oxacillinases (CHDL) hydrolyse carbapenems and render them inactive. They belong to class D according to Ambler. Oxacillinases of the genus Acinetobacter are classified into five phylogenetic groups, the intrinsic OXA-51-like and the acquired enzymes: OXA-23-like , OXA-24/40-like, OXA-58- like, OXA-143-like, and OXA-235-like. The study revealed oxacillinases (the chromosomally and plasmid-encoded OXA-51 and both OXA-23 and OXA-40, respectively) capable of hydrolysing carbapenems, beta-lactam antibiotics that before the advent of treatment with collistin often proved as a last resort in treating infections with this pathogen. Molecular characterization and strain typing are of great epidemiological value because of the importance of tracing the source of resistant strains as well as the possibility to develop targeted infection-control strategies. Isolates producing OXA-24/40 were clonally related.

• Keywords: Acinetobacter; karbapenemaze; oksacilinaze; rezistencija
• Keywords (english): Acinetobacter; carbapenemases; oxacillinases; resistance
• Language: croatian
• URN:NBN: urn:nbn:hr:105:180959
• Study programme: Title: Medicine; Study programme type: university; Study level: integrated undergraduate and graduate; Academic / professional title: doktor/doktorica medicine (doktor/doktorica medicine)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Open access
• Created on: 2019-03-26 13:44:23