John Snow's Cholera Identification & Antibiotics Mechanism of Action

This assignment explores John Snow's identification of cholera transmission in 19th-century Britain, focusing on his mapping of deaths to contaminated water sources, which disproved the miasma theory. It also details how antibiotics combat bacterial infections by disrupting vital processes, either killing bacteria (bactericidal) or inhibiting their growth (bacteriostatic). The assignment differentiates between broad and narrow-spectrum antibiotics, explaining mechanisms like cell wall disruption (e.g., penicillin) and interference with protein synthesis (e.g., erythromycin), ultimately aiding the body's immune response. Desklib offers further study resources and solved assignments for students.

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Identification of Cholera by John Snow......................................................................................1
How do antibiotics work..............................................................................................................1

Identification of Cholera by John Snow
In the nineteen century, Cholera was considered to be a deadly disease in Britain. It was
believed to be spreading through bad air or smells from rotten organic matter. In 1831, during
outbreak of cholera, John was attending to the patients in the Killingworth Colliery which
allowed him to make some important observations regarding the disease. When the outbreak
reached Soho, Snow identified that contaminated public water is the source of outbreak. He
could identify this by mapping the deaths from cholera which were found to be in mostly those
people who had the nearest access to the Board Street pump. This observation was relevant as
during that time, Soho had unhygienic conditions due to large influx of people and inadequate
sanitary services.
The pattern identified by Snow was valid as later it was identified that the water of the
pump was contaminated by the sewage that contained cholera as there was a cesspit nearby.
Snow’s theory had argued that cholera was not due to air, but as the germ theory was not
developed by that time. Snow was unaware of mechanism of disease transmission. However, the
evidence collected by him through mapping of death enabled him to deduce that cholera was not
spread due to foul air. Snow recorded cholera attacks in the area and also collected information
about the water supply to those areas. It was found that those areas were being delivered sewage
contaminated water which further added to the increased incidence of cholera.
How do antibiotics work
Antibiotics are used in the treatment and prevention of various types of bacterial
infections. They kill bacteria or prevent their further spread. They work by creating a block in the
vital processes of bacteria which either kills them or stops them from growing in number.
Essential processes of the bacterial cell are disrupted by the antibiotics. Due to this, with the
bacterial cell is killed or its growth stops. As a result of this, assistance is provided to the natural
immune system of the body to fight the bacteria infection. Broad spectrum antibiotics work
against a wide range of bacteria. Narrow spectrum antibiotics affect only few types of bacteria.
The working of different types of antibiotics is different. Some of them work by
destroying the bacterial cell walls or the membrane surrounding the cell, for example Penicillin.
This causes cell injury and leads to the loss of ability of bacteria to attack the body. These are
known as bactericidal antibiotics and perform the work of killing the bacterial cells. Other
antibiotics impact the working of the bacterial cells. These impact the components that make the
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nucleic acids as well as the machinery which is responsible for producing proteins. For example,
erythromycin. These block the reproduction of bacteria and are known as bacteriostatic. These
block the process of nutrients reaching bacteria thus leading to inability to multiply. In this way,
these antibiotics stop the infection and the immune system of the body gets time to attack.
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