linens eat the dead skin on our feet, a smelly acid is released.
z Fig. 5.2.3
Probiotic products contain living cultures of bacteria
The Negative Effects of Bacteria
Although most bacteria are harmless, some can have negative effects: zz
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Food spoilage: Flavobacterium causes food products with a high sugar content to spoil.
Livestock and crop diseases: some bacteria live on or in another organism and cause it harm. For example, Streptomyces scabies causes scabs on potato tubers.
zz z Fig. 5.2.4 Streptomyces scabies on a potato
Human diseases: a small number of bacteria also cause human diseases. For example, Streptococcus mutans causes tooth decay.
Antibiotic Resistance
An antibiotic is a chemical produced by microorganisms that is used as a drug to treat certain diseases caused by bacteria and fungi.
The speed at which bacteria reproduce can help them evolve a resistance to antibiotics. This makes it more difficult to treat diseases caused by bacteria.
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Fig. 5.2.5 Tooth decay
Causes
The use of antibiotics to treat viral infections – antibiotics have no effect on viruses
Patients not completing the full course of antibiotics
The widespread use of antibiotics in agriculture
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The way we use antibiotics has added to this problem. The following table outlines how humans have encouraged antibiotic resistance and how we might prevent it in future.
Prevention
Do not prescribe antibiotics for viral diseases such as colds and flu
Finish full course of antibiotics Regulation of the use of antibiotics in farming
