Universität zu Köln

Plambeck, Lars (2024). In vitro Empfindlichkeit von Mecillinam, Temocillin und Nitroxolin gegenüber mutiresistenten Enterobakterien. PhD thesis, Universität zu Köln.

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Abstract

Background: With increasing resistance to common antibiotics the treatment of urinary tract infections has become challenging and alternative therapeutic options are needed. In the present study, we evaluate the ac- tivity of three older and less frequently used antibiotics against MDR Enterobacterales. Methods: Susceptibility of mecillinam, temocillin and nitroxoline was assessed in Enterobacterales isolated from urinary specimens with elevated MICs of third-generation cephalosporins. Susceptibility was determined by the recommended reference MIC methods and additionally by disc diffusion. All isolates were characterized for common β-lactamases by phenotypic and molecular assays. Results: In total 394 Enterobacterales were included. The most common resistance mechanisms were ESBLs (n=273), AmpC (n=132), carbapenemases [n=12, including OXA-48-like (n=8), VIM (n=2), KPC (n=1) and NDM (n=1)] or others (n=2). Resistance was observed in 59% of isolates to ceftazidime, in 41% to piperacil- lin/tazobactam and in 54% to ciprofloxacin. In comparison, resistance was less frequent against mecillinam (15%), temocillin (13%) or nitroxoline (2%). Mecillinam showed higher activity in Enterobacter spp., Escherichia coli and in OXA-48-like-producing isolates compared with temocillin, which was more active in Proteus mirabilis and in ESBL-producing isolates. Activity of nitroxoline was high against all isolates, including carbapenemase-producing isolates. Correlation between disc diffusion and MIC methods was good for mecillinam and moderate for temocillin and nitroxoline. Conclusions: Mecillinam, temocillin and nitroxoline show good to excellent in vitro activity in MDR Enterobacterales. The activity of mecillinam and temocillin was higher in certain species and restricted depending on β-lactamase production while nitroxoline showed universally high activity irrespective of species or β-lactamase present.

Item Type:	Thesis (PhD thesis)
Creators:	Creators Email ORCID ORCID Put Code Plambeck, Lars UNSPECIFIED UNSPECIFIED UNSPECIFIED
URN:	urn:nbn:de:hbz:38-727793
Date:	2024
Language:	German
Faculty:	Faculty of Medicine
Divisions:	Faculty of Medicine > Medizinische Mikrobiologie, Immunologie und Hygiene
Subjects:	Medical sciences Medicine
Uncontrolled Keywords:	Keywords Language In vitro Empfindlichkeit UNSPECIFIED Mecillinam UNSPECIFIED Temocillin UNSPECIFIED Nitroxolin UNSPECIFIED Enterobakterien UNSPECIFIED Multiresistenz UNSPECIFIED
Date of oral exam:	16 April 2024
Referee:	Name Academic Title Hamprecht, Axel Prof. Dr. med. Rybniker, Jan PD Dr. med. Dr. nat. med.
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/72779