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The
connection between life and bacteria remain sometimes positive and sometimes
negative. Human body has multiple bacteria in our bodies, who resides in
colonies in guts or skins.
The interesting fact about bacteria is that they have survived long.
The interesting fact about bacteria is that they have survived long.
Our
predecessors have been bacteria, and perhaps longest living beings on the
earth. The total number
of bacteria is astounding — five million trillion trillion (a five with 30
zeros after it). To be precise that will not be wrong to call that there are
far more bacteria on Earth than there are stars on the universe.
Bacteria
which resides in our guts effect human so much that they even manipulate that
we like socialisation or not. In fact, the death of gut bacteria can lead to
human in to depression.
They also help with immunity, making the body less
hospitable to bad bacteria and other harmful pathogens
However,
the problem is often when a bacteria spreads among humans and harms them.
What is a bacteria?
Bacteria are microscopic, single-cell organisms that live
almost everywhere. Bacteria live in every climate and location on earth. Some
are airborne while others live in water or soil. Bacteria live on and inside
plants, animals, and people.
The word "bacteria" has a negative connotation,
but bacteria actually perform many vital functions for organisms and in the
environment. For example, plants need bacteria in the soil in order to grow.
The
evolution of Bacteria.
The
earliest bacteria seemed to be on the earth for the last 3.8 to 4 billion
years. Like any other living entity, they
depend upon the environment.
Humans
have evolved; however, the term evolution works on almost ‘every’ species. Bacteria
also have evolved and adapted to their environment for their survival, and that
is when their existence comes to an struggle with humans.
Some
of the bacteria which are unsafe for human health, they feed on human’s health.
This ends often in an human infection or a disease. Bacteria keep on feeding,
until the cure is found.
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What is bacterial infection?
A bacterial infection is a proliferation of a harmful strain
of bacteria on or inside the body. Bacteria can infect any area of the body. Pneumonia, meningitis, and food poisoning are just a few illnesses that may be caused by harmful
bacteria.
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Bacteria come in three basic shapes: rod-shaped (bacilli), spherical
(cocci), or helical (spirilla).
Bacteria may also be classified as
gram-positive or gram-negative. Gram-positive bacteria have a thick cell wall
while gram-negative bacteria do not. Gram staining, bacterial culture with
antibiotic sensitivity determination, and other tests are used to identify
bacterial strains and help determine the appropriate course of treatment.
What is the
difference between Bacteria and virus?
Bacteria and viruses are different types of pathogens, organisms that can cause
disease. Bacteria are larger than viruses and are capable of reproducing on
their own. Viruses are much smaller than bacteria and cannot reproduce on their
own.
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Instead, viruses reproduce by infecting a host and using the host's DNA
repair and replication systems to make copies of itself.
Types of
Infections caused by Bacteria
The symptoms of a bacterial or viral infection depend on the
area of the body that is affected. Sometimes the symptoms of the two can be
very similar. For example, runny nose, cough, headache, and fatigue can occur with the common cold (virus) and with a sinus infection (bacteria).
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A doctor may use the presence of other symptoms (such as
fever or body aches), the length of the illness, and certain lab tests to
determine if an illness is due to a virus, bacteria, or some other pathogen or
disease process.
Bacterial skin infections are usually caused by
gram-positive strains of Staphylococcus and Streptococcus or other organisms.
Bacterial infections are one cause of foodborne illness as
well. Nausea, vomiting, diarrhea,
fever, chills, and abdominal pain are
common symptoms of food poisoning. Raw meat, fish, eggs, poultry, and
unpasteurized dairy may harbor harmful bacteria that can cause illness.
Unsanitary food preparation and handling can also encourage bacterial growth.
Many sexually transmitted diseases (STDs) are caused
by harmful bacteria. Sometimes, these infections aren't associated with any
symptoms but can still cause serious damage to the reproductive system.
Antibiotics are medications that fight bacterial infections.
They work by disrupting the processes necessary for bacterial cell growth and
proliferation.
The New Challenge in stopping
the infection caused by bacteria.
Sometimes, bacteria develops anti-biotic
resistance.
Even
as we discover drugs and molecules to fight them, bacteria quickly mutate,
resist. And we humans have
tried various ways to fight these infections using herbs and drugs since
ancient times.
Methods
to fight against bacteria
Dr Rustam Aminov writes in his
paper: “A brief history of the antibiotic era: Lessons learned and challenges
for the future” (Frontiers in Microbiology, 8 Dec 2010) that ancient Egyptians
tried using poultices of moulded bread against infection and ancient Sudanese
skeletons had traces of the antibiotic tetracycline — obviously from some herb
they would have used against microbial infections.
The day of modern medical
treatment is recent. Dr. Hara discovered the compound arsphenamine to fight
syphilis in 1909 and Dr. Bertheim synthesised it and called it salvarsan in
1910. And in 1928, Alexander Fleming discovered penicillin, which could kill a
large number of infecting bacteria.
What
is the problem with bacteria?
Even as we discover more and
more drugs and molecules to fight them, bacteria quickly change their genetic
composition by mutation and resist the action of the drug.
The crucial is to understand
the biological steps involved in bacterial infections. That is when the weakest
zone can be identified which may ultimately lead to a victory against bacteria.
It is towards this challenge
that microbiologists have been studying the molecular biology of bacteria using
the species called Escherichia coli (E. coli for short) as the
model organism in the laboratory.
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We now know that bacterial
cells are surrounded by a protective cell wall made up of a large sac-like
structure called peptidoglycan or PG. The PG that bacteria use to build their
cell walls is specific to them alone, and not found anywhere else on earth.
The PG is a baglike structure
which is made of sheets of two sugar molecules, NAG and NAM, linked together as
long chains.
These sheets are cross-linked
or stapled together to form a continuous layer around the bacterial cells.
Therefore, as the bacterium
grows in size, this PG bag also has to expand. That means the stapler has to be
opened, new material incorporated and the bag stapled again into compactness
for successful bacterial growth.
Key step
An important step towards this
has been made by Dr. Manjula Reddy and her colleagues at the Centre for
Cellular and Molecular Biology (CCMB) at Hyderabad.
Her group has been studying
the basic biology behind how the bacterium builds its cell wall, how the bag
opens for growth, and what molecules help in opening the bag.
Her group has identified a
particular class of enzymes, which are responsible for unstapling the PG bag
(see their publications: Singh et al., Mol. Microbiol., 2012; 86(5),
1036-1051; Singh et al., PNAS, 112, 10956-10961; Chodisetti et al., PNAS,
April 2, 2019; https://doi.org/10.1073/pnas.1816893116).
They further showed that if
any or all of these enzymes are removed from the bacterium (using genetic
engineering methods), the PG bag does not open, starving the bug to death.
What does this mean? If we can
find molecules or methods to inhibit these enzymes, and thus arrest the
infecting bacterium from making its protecting cell wall, we will have found a
way to overcome infection and offer safety.
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A differing approach is used
against the bacteria
Incidentally, the classical
antibiotic, penicillin, inhibits the enzymes which help in re-stapling the
once-opened cell wall, thus weakening the bug and killing it.
While this approach is a “do
not close the wall” one, the CCMB approach is a “keep the cell wall shut and
never open it”.
The currently popular class of
antibiotics, called the fluoroquinolones (such as ciprofloxacin), acts not on
the cell wall, but inhibits the enzymes that allow the DNA of the bacterium to
open up and replicate itself.
These drugs thus inhibit the reproduction and
repair of genes of the infecting bacteria.
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