Universität zu Köln

Zander, Esther, Seifert, Harald and Higgins, Paul G. ORCID: 0000-0001-8677-9454 (2016). Effects of Saline, an Ambient Acidic Environment, and Sodium Salicylate on OXA-Mediated Carbapenem Resistance in Acinetobacter baumannii. Antimicrob. Agents Chemother., 60 (6). S. 3415 - 3419. WASHINGTON: AMER SOC MICROBIOLOGY. ISSN 1098-6596

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Abstract

Different physiological conditions, such as NaCl, low pH, and sodium salicylate, have been shown to affect antibiotic resistance determinants in Acinetobacter baumannii isolates. Therefore, the aim of this study was to investigate the effects of NaCl, sodium salicylate, and low pH on the susceptibility of A. baumannii to carbapenem. We cloned genes encoding oxacillinases (OXA) of different subclasses, with their associated promoters, from carbapenem-resistant A. baumannii isolates into the same vector and transferred them to the A. baumannii reference strains ATCC 19606 and ATCC 17978. Carbapenem MICs were determined at least in triplicate by agar dilution under standard conditions, as well as in the presence of 200 mM NaCl or 16 mM sodium salicylate, or at pH 5.8. OXA-58-like gene expression was determined by reverse transcription-quantitative PCR (qRT-PCR). Under some experimental conditions, significant MIC reductions were shown for some transformants but not for others. Only in one instance were all transformants harboring the same OXA affected by the same condition: at pH 5.8, the imipenem and meropenem MICs for strains expressing OXA-58-like enzymes decreased from a resistant level (32 to 64 mg/liter) to an intermediate-susceptible level (8 mg/liter). However, bla(OXA-58-like) gene expression remained the same. MICs for both wild-type reference strains were not affected by the conditions tested. Our results indicate that the effects of the experimental conditions tested on OXA in vivo are mostly strain dependent. MICs were not reduced to wild-type levels, suggesting that the conditions tested do not lead to complete OXA inhibition in the bacterial cell.

Item Type:	Journal Article
Creators:	Creators Email ORCID ORCID Put Code Zander, Esther UNSPECIFIED UNSPECIFIED UNSPECIFIED Seifert, Harald UNSPECIFIED UNSPECIFIED UNSPECIFIED Higgins, Paul G. UNSPECIFIED orcid.org/0000-0001-8677-9454 UNSPECIFIED
URN:	urn:nbn:de:hbz:38-274262
DOI:	10.1128/AAC.03010-15
Journal or Publication Title:	Antimicrob. Agents Chemother.
Volume:	60
Number:	6
Page Range:	S. 3415 - 3419
Date:	2016
Publisher:	AMER SOC MICROBIOLOGY
Place of Publication:	WASHINGTON
ISSN:	1098-6596
Language:	English
Faculty:	Unspecified
Divisions:	Unspecified
Subjects:	no entry
Uncontrolled Keywords:	Keywords Language OUTER-MEMBRANE PROTEIN; MOLECULAR EPIDEMIOLOGY; STABILITY; GENE; BLA(OXA-58); CONVERSION; MEROPENEM; EMERGENCE; CLONES; PUMPS Multiple languages Microbiology; Pharmacology & Pharmacy Multiple languages
Refereed:	Yes
URI:	http://kups.ub.uni-koeln.de/id/eprint/27426