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The nutritional requirements of methicillin-dependent and -resistant strains of Pediococcus cerevisiae
Abstract:
A new methicillin-dependent and -resistant substrain (called MRD) of Pediococcus cerevisiae was developed by serial passages followed by replica-plating. Other methicillin-resistant, but not -dependent, substrains were isolated after treatment of the same parent strain with a mutagen. A methicillin-independent partial revertant, still resistant to the drug, was isolated from the original methicillin-dependent and -resistant substrain (CRD) developed several years ago. The requirements of some of these strains for acetate, vitamins and amino acids were compared. All except the parent methicillin-sensitive strain required pantothenate for growth, but no other consistent differences were found. The parent, but not strain CRD, grew without lysine added to the medium, though 19 other amino acids were needed by each strain. Both of these strains fermented glucose to lactate (mainly the L-isomer) in the absence or presence of methicillin.
Insights
Researchers developed new methicillin-resistant strains of Pediococcus cerevisiae. These resistant Pediococcus cerevisiae strains showed altered nutrient requirements, impacting their growth and fermentation capabilities.
Area of Science:
- Microbiology
- Bacterial Genetics
Background:
- Pediococcus cerevisiae is a bacterium relevant in food fermentation.
- Methicillin resistance in bacteria is a significant public health concern.
- Understanding the genetic and metabolic basis of antibiotic resistance is crucial.
Purpose of the Study:
- To develop and characterize methicillin-resistant substrains of Pediococcus cerevisiae.
- To investigate the nutritional requirements of these novel substrains.
- To compare the growth and fermentation characteristics of resistant strains with the parent strain.
Main Methods:
- Serial passages and replica-plating were used to develop methicillin-dependent and -resistant substrains.
- Mutagenesis was employed to generate other methicillin-resistant substrains.
- Nutritional analyses compared requirements for acetate, vitamins, and amino acids.
- Fermentation of glucose to lactate was assessed in the presence and absence of methicillin.
Main Results:
- A new methicillin-dependent and -resistant substrain (MRD) was successfully developed.
- Methicillin-resistant, but not methicillin-dependent, substrains were isolated after mutagenesis.
- A methicillin-independent revertant strain (still resistant) was identified.
- Most resistant strains, unlike the parent strain, required pantothenate for growth.
- All strains, except the parent, required lysine, with only minor amino acid differences noted.
- Both parent and CRD strains fermented glucose to lactate, irrespective of methicillin presence.
Conclusions:
- Methicillin resistance in Pediococcus cerevisiae can be induced through various methods, leading to distinct substrains.
- Acquired methicillin resistance is associated with altered auxotrophic requirements, particularly for pantothenate.
- The fermentation capabilities of Pediococcus cerevisiae remain largely unaffected by methicillin resistance under tested conditions.