Otpornost na karbapeneme i kolistin u enterobakterija iz otpadnih voda

master's thesis

• Title (english): Resistance to carbapenems and colistin in enterobacteria from wastewaters
• Author: Valentina Žuljević
• Mentor: Mirna Mrkonjić Fuka (mentor)
• Mentor: Nikolina Udiković Kolić (komentor)
• Committee member: Mirna Mrkonjić Fuka (predsjednik povjerenstva)
• Committee member: Marko Vinceković (član povjerenstva)
• Committee member: Vilim Filipović (član povjerenstva)
• Granter: University of Zagreb; Faculty of Agriculture; (Microbiology); Zagreb
• Defense date and country: 2020-09-30, Croatia
• Scientific / art field, discipline and subdiscipline: BIOTECHNICAL SCIENCES; Agronomy

Abstract

S obzirom da se karbapenemi koriste kao lijekovi posljednje linije obrane u liječenju infekcija
uzrokovanih višestruko otpornim enterobakterijama, rastuća prevalencija enterobakterija
otpornih na karbapeneme postaje sve veći problem na globalnoj razini. Smatra se da bi ispusti
neadekvatno obrađenih otpadnih voda mogli doprinijeti ovom problemu. Cilj ovog diplomskog
rada bio je odrediti fenotipsku osjetljivost 200 izolata enterobakterija, izoliranih iz zagrebačkih
komunalnih i bolničkih otpadnih voda, na karbapeneme i druge klinički važne antibiotike te
utvrditi dominantan mehanizam otpornosti na karbapeneme u karbapenem-otpornim
izolatima. Metodom mikrodilucije testirana je osjetljivost izolata na 3 karbapenema
(ertapenem, imipenem, meropenem) pri čemu je većina izolata, bolničkih i komunalnih, bila
otporna na sva 3 testirana karbapenema. Kolorimetrijskim CarbaNP testom potvrđeno je da
je otpornost na karbapeneme u većini analiziranih izolata bila posredovana proizvodnjom
karbapenemaza. Ti su izolati uglavnom bili otporni na sve testirane skupine β-laktamskih
antibiotika te na fluorokinolone, što je utvrđeno metodom disk difuzije. Povrh toga, manji dio
izolata (uglavnom <50%) ispoljavao je otpornost i na aminoglikozide te kombinaciju
sulfonamid-trimetoprim, što je utvrđeno metodom disk difuzije kao i na kolistin, što je
potvrđeno metodom mikrodilucije. Većina izolata ispoljavala je višestruko otporan fenotip tj.
otpornost na barem 3 klase antibiotika, što je bilo više izraženo kod bolničkih izolata. Većina
tih višestruko-otpornih izolata ispoljavala je otpornost na karbapeneme putem proizvodnje
karbapenemaza. Rezultati ovog istraživanja ukazuju da su bolničke i obrađene komunalne
otpadne vode čimbenici koji doprinose širenju višestruko otpornih enterobakterija u okoliš,
što predstavlja rizik za zdravlje ljudi. Posebice zabrinjava mogućnost širenja enterobakterija
otpornih na karbapeneme i kolistin ovim putem.

Abstract (english)

Considering that carbapenems are used as last-resort medicine in the treatment of infections
caused by multidrug-resistant enterobacteria, increasing prevalence of carbapenem-resistant
enterobacteria is becoming a growing problem on the global scale. It is considered that
discharge of inadequately processed wastewaters could contribute to this problem. The aim
of this master thesis was to determine phenotypic susceptibility of 200 enterobacterial
isolates, isolated from Zagreb’s communal and hospital wastewaters, to carbapenems and
other clinically important antibiotics and to determine dominant mechanism of resistance to
carbapenems in carbapenem-resistant isolates. Susceptibilty of isolates to 3 carbapenems
(ertapenem, imipenem, meropenem) was tested by microdilution method where most of the
isolates, communal and hospital, were resistant to all 3 tested carbapenems. Colorimetric
CarbaNP test confirmed that carbapenem-resistance for most of the analyzed isolates was
mediated by carbapenemase production. These isolates were mostly resistant to all groups of
β-lactam antibiotics and fluoroquinolones, what was determined by disk diffusion method. On
top of that, smaller part of isolates (mainly <50%) also manifested resistance to
aminoglycosides and sulfonamide-trimethoprim combination, what was determined by disk
diffusion method and also resistance to colistin, what was confirmed by microdilution method.
Most of the isolates manifested multidrug-resistant phenotype ie. resistance to at least 3
classes of antibiotics, what was more prominent in hospital isolates. Most of these multidrugresistant
isolates manifested resistance to carbapenems by carbapenemase production.
Results of this research point out hospital and processed communal wastewaters as factors
that contribute to the spread of multidrug-resistant enterobacteria in the environment, which
presents a risk for human health. Especially worrying is the possibility of spreading
enterobacteria resistant to carbapenems and colistin in this manner.

• Keywords: enterobakterije; antibiotička otpornost; otpadne vode; karbapenemi; kolistin; višestruka otpornost
• Keywords (english): enterobacteria; antibiotic resistance; wastewaters; carbapenems; colistin; multidrug-resistance
• Language: croatian
• URN:NBN: urn:nbn:hr:204:729710
• Study programme: Title: Agroecology; Study programme type: university; Study level: graduate; Academic / professional title: magistar/ magistra inženjer/inženjerka agroekologije (magistar/ magistra inženjer/inženjerka agroekologije)
• Type of resource: Text
• File origin: Born digital
• Access conditions: Access restricted to students and staff of home institution
• Created on: 2020-10-30 11:23:05