Sensitivity of Yersinia kristensenii to Beta-lactam antibiotics, H2O2 and production of SH groups in the presence of thiamine
1998
Hustavova, H. (Institute of Preventive and Clinical Medicine, Bratislava (Slovak Republic))
Changes in resistance to Beta-lactam antibiotics, H2O2 and in the production of SH groups were investigated in the course of adaptation to thiamine over 4 passages in Yersinia kristensenii 13, 15 and 18 also during repeated cultivation with CdSO4 (2 and 20 mg/l) in M9 medium supplemented with glucose (2.5 g/l) and thiamine (5 mg/l) and in nutrient broth (NB). Resistance to beta-lactams neither in isolates nor in their Cd-treated cultures exceeded the threshold value of 16 mg/l and resistance to H2O2 was strain-specifically increased in NB. In isolates as well as in the Cd-treated cultures thiamine induced increased resistance to ampicillin (AMPI) and cefazolin (CFAZ) only in passages 1 and 2. In passages 3 and 4 the levels determined in NB were restored or were lower. Increased sensitivity to H2O2 in passage 1 was replaced by extreme resistance in passage 2. In passage 3, hypersensitivity (strain 13) or even inability (strain 18) to grow in the presence of H2O2 was observed in the Cd-treated cultures. Risk of oxidative stress was not shown in passage 4. Thiamine enhanced the production of protein SH groups (PSH), however their initial content during adaptation decreased by 8-10 nmol/10E8 cells in Cd-treated cultures and also in strain 18. Production of non-protein SH groups (NSH) was reduced in a stepwise manner (passage 4) to zero level. In passage 4 a slow growth was observed in all cultures except for the Cd-untreated strain 15. This strain may have become adapted to thiamine, and this adaptation may protect the cells from the cytotoxic action of H2O2 in the presence of Cd
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