The role of thiamine inYersinia kristensenii resistance to antibiotics and heavy metals |
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Authors: | H. Hušťavová D. Havraneková |
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Affiliation: | (1) Institute of Preventive and Clinical Medicine, 833 01 Bratislava |
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Abstract: | The resistance to divalent metal ions, antibiotics and H2O2 was investigated inYersinia kristensenii strains 13, 15, 18 by performing subcultivations with CdSO4 (20 and 100mg/L) in nutrient agar (NA) and M9 medium with thiamine. Metal resistance of all three strains in NA was the same and decreased in the following sequence: Ni>Zn=Co>Cd. The chloramphenicol (Cmp) resistance ranged between 32 and 256 mg/L and the H2O2 sensitivity was very low or even zero. In the presence of thiamine the metal resistance sequence changed to Zn=Cd>Ni, Co, Ni and Co tolerance being 10–20 mg/L. Cmp resistance of all strains increased to 256 mg/L and H2O2 sensitivity also rose. In Cd-treated cultures, the ratio of glucose to thiamine in culture medium affected Cd resistance. At normal content of glucose and thiamine (5 g/L and 5mg/L), Cd resistance markedly decreased coincident with thiamine exhaustion in these slowly-growing cultures. The Cmp resistance decreased to 16 mg/L, Ni and Co intolerance and H2O2 hypersensitivity appeared. At lowered glucose or thiamine levels (5 g/L and 2.5 mg/L or 2.5 g/L and 5 mg/L) a marginal decrease of Cd resistance took place in response to limited glucose uptake. Low thiamine or low-glucose cultures were resistant to H2O2, and exhibited a small decrease in Cmp resistance and a low Ni, Co tolerance. The adaptation of strain 15 to Cd induced only a small decrease of Cd resistance. Lowered glucose-to-thiamine ratio in culture medium probably induced in Cd-treated cultures a response triggering Cd resistance. |
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