MICROBILOLGY

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INSTITUTE OF ENGINEERING & MANAGEMENT, KOLKATA
Course Name :

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INSTITUTE OF ENGINEERING & MANAGEMENT, KOLKATA
Topic – Microbiology
Prof. Dibakar Roy Choudhury
Department of Basic Science and Humanities

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INSTITUTE OF ENGINEERING & MANAGEMENT, KOLKATA
What is microbiology ??
• Microbiology is the study of microscopic organisms, those being
unicellular (single cell), multicellular (cell colony), or acellular (lacking
cells)
• Microorganisms are typically too small to be seen with the naked eye.
Bacteria, fungi, viruses, protozoa, and algae are the major groups of
microorganisms.
• The vast majority of microorganisms are not harmful but rather
beneficial.
• Microbiota refers to all of the microorganisms that live in a particular
environment.
• A microbiome is the entire collection of genes found in all of the
microbes associated with a particular host.

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Introduction to Microbiology
• Microorganisms are the dominant life forms on earth, are found in
almost every conceivable environment, and are essential to sustaining
life on this planet. There are five basic groups of microorganisms:
– Bacteria are typically unicellular, microscopic, prokaryotic
organisms that reproduce by binary fission.
– Fungi (yeasts and molds) are typically unicellular, microscopic,
eukaryotic fungi that reproduce asexually by budding. Molds are
typically filamentous, eukaryotic fungi that reproduce by
producing asexual reproductive spores.
– Viruses are typically submicroscopic, acellular infectious particles
that can only replicate inside a living host cell. The vast majority of
viruses possess either DNA or RNA, but not both.

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Introduction to Microbiology(continued)
• Protozoa are typically unicellular, microscopic, eukaryotic organisms
that lack a cell wall.
• Algae are typically eukaryotic microorganisms that carry out
photosynthesis.

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Benefits of Microbial Activity
• Food production: Many food products employ microorganisms in
their production. These include the microbial fermentation processes
used to produce yogurt, buttermilk, cheeses, alcoholic beverages,
leavened breads, sauerkraut, pickles, and kimchi.
• Energy production and cleaning up the environment:
– Methane, or natural gas, is a product of methanogenic
microorganisms. Many aquatic microbes capture light energy and
store it in molecules used as food then used by other organisms.
– Animal wastes, domestic refuse, biomass, and grain can be
converted to biofuels such as ethanol and methane by
microorganisms.

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Benefits of Microbial Activity
• Sustaining agriculture: Through their roles in recycling nitrogen,
carbon, and sulfur, microorganism are able to convert these essential
elements into forms that can be used by plants in their growth.
• Production of useful natural gene products or products from
bioengineering. Examples include specific enzymes, antibiotics,
vaccines, and medications such as human insulin, interferons, and
growth hormones.

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Human microbiota and their role in human health
• The typical human body contains an estimated 37 trillion human cells,
it also contains over 100 trillion bacteria and other microbes. The
human body has 3 times as many bacterial cells as it does human cells!
It is estimated the the mass of the human microbiota is 2.5 pounds.
• The complex mutually beneficial symbiotic relationship between
humans and their natural microbes is critical to good health.
• It is now recognized that the millions of genes associated with the
microbiota of the human body -especially in the intestinal tract - aid in
the digestion of many foods, the regulation of multiple host metabolic
pathways, and the regulation the body's immune defences.

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Human microbiota and their role in human health
• The mutually beneficial interaction between the human host and its
resident microbiota is essential to human health. Microbial genes
produce metabolites essential to the host while human genes
contribute to development of the microbiota. The microbiome aids in
the following:
– The digestion of many foods, especially plant polysaccharides that
would normally be indigestible by humans.
– The regulation of many host metabolic pathways. The metabolism
of many substrates in the human body is carried out by a
combination of genes from both the microbiome and the body's
susceptibility to disease.
– Metabolic disorders such as diabetes, hypertension, obesity, gastric
ulcers, colon cancer, and possibly some mood and behavior
changes through hormone signaling have been linked to alterations
in the microbiota.

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Human microbiota and their role in human health

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Harmful effect of microorganisms
• Infectious diseases are disorders caused by organisms — such as
bacteria, viruses, fungi or protozoa. Many organisms live in and on
our bodies. They're normally harmless or even helpful. But under
certain conditions, some organisms may cause disease.
• Some infectious diseases can be passed from person to person. Some
are transmitted by insects or other animals. And you may get others by
consuming contaminated food or water or being exposed to organisms
in the environment.

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Some bacterial disease
• Pneumonia is an infection of the lungs. Symptoms include a high fever,
coughing, and difficulty breathing.
• While a number of bacteria can cause pneumonia, the most common
cause is Streptococcus pneumoniae.
• S. pneumoniae typically reside in the respiratory tract and don't
normally cause infection in healthy individuals. In some cases, the
bacteria become pathogenic and cause pneumonia.
• The infection typically begins after the bacteria are inhaled and
reproduce at a rapid rate in the lungs.
• S. pneumoniae can also cause ear infections, sinus infections, and
meningitis.
• If needed, most pneumonia has a high probability of cure with
antibiotic treatment. A pneumococcal vaccine can help protect those
who are most at risk of developing this disease.

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Some bacterial disease(continued)
• Tuberculosis (TB) is an infectious disease of the lungs. It is typically
caused by bacteria called Mycobacterium tuberculosis.
• Tuberculosis can be deadly without proper treatment. The disease is
spread through the air when an infected person coughs, sneezes, or
even talks. In a number of developed countries,
• Antibiotics are used to treat tuberculosis. Isolation to help prevent the
spread of an active infection is also typical of treating this disease.
• Treatment can be long, lasting from six months to a year, depending
on the severity of the infection.

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Some bacterial disease(continued)
• Cholera is an intestinal infection caused by the bacteria Vibrio
cholerae.
• Cholera is a food-borne disease typically spread by food and water
contaminated with Vibrio cholerae.
• Around the world, approximately 3 to 5 million cases per year with
approximately 100,000 plus deaths occur. Most instances of infection
occur in areas with poor water and food sanitation.
• Cholera can range from mild to severe. Symptoms of the severe form
include diarrhea, vomiting, and cramps.
• Cholera is typically treated by hydrating the infected individual. In
more severe cases, antibiotics may be used to help the person recover.

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Antibiotic
• Antibiotics are a group of medicines that are used to treat infections
caused by some germs (bacteria and certain parasites). They do not
work against infections that are caused by viruses - for example, the
common cold or flu.
• Antibiotics are normally only prescribed for more serious bacterial
infections, as many infections get better on their own. Correct use of
antibiotics is absolutely essential to help reduce antibiotic resistance.
Germs become resistant to antibiotics over time, which then makes
them less effective.

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Some example of Antibiotic
• There are various antibiotics available and they come in various
different brand names. Antibiotics are usually grouped together based
on how they work. Each type of antibiotic only works against certain
types of bacteria or parasites. This is why different antibiotics are used
to treat different types of infection. The main types of antibiotics
include:
• Penicillin-
forexample, phenoxymethylpenicillin, flucloxacillin and amoxicillin
• Cephalosporins - for example, cefaclor, cefadroxil and cefalexin.
• Tetracyclines - for example, tetracycline, doxycycline and lymecycline.
• Aminoglycosides - for example, gentamicin and tobramycin.
• Macrolides - for example, erythromycin, azithromycin

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Antibiotic resistant Bacteria
• Antibiotic resistant bacteria are bacteria that are not controlled or
killed by antibiotics. They are able to survive and even multiply in the
presence of an antibiotic. Most infection-causing bacteria can become
resistant to at least some antibiotics. Bacteria that are resistant to
many antibiotics are known as multi-resistant organisms (MRO).
• Antibiotic resistance is a serious public health problem. It can be
prevented by minimising unnecessary prescribing and overprescribing
of antibiotics, the correct use of prescribed antibiotics, and good
hygiene and infection control.
• Some bacteria are naturally resistant to some antibiotics. For
example, benzyl penicillin has very little effect on most organisms
found in the human digestive system (gut).

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Some viral disease
• Coronavirus disease (COVID-19) is an infectious disease caused by a
newly discovered coronavirus.
• Most people infected with the COVID-19 virus will experience mild to
moderate respiratory illness and recover without requiring special
treatment. Older people, and those with underlying medical problems
like cardiovascular disease, diabetes, chronic respiratory disease, and
cancer are more likely to develop serious illness.

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Some viral disease(continued)
• The best way to prevent and slow down transmission is be well
informed about the COVID-19 virus, the disease it causes and how it
spreads. Protect yourself and others from infection by washing your
hands or using an alcohol based rub frequently and not touching your
face.
• The COVID-19 virus spreads primarily through droplets of saliva or
discharge from the nose when an infected person coughs or sneezes, so
it’s important that you also practice respiratory etiquette (for example,
by coughing into a flexed elbow).

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Some viral disease(continued)
• Acquired immunodeficiency syndrome (AIDS) is a chronic,
potentially life-threatening condition caused by the human
immunodeficiency virus (HIV). By damaging your immune system, HIV
interferes with your body's ability to fight infection and disease.
• HIV is a sexually transmitted infection (STI). It can also be spread by
contact with infected blood or from mother to child during pregnancy,
childbirth or breast-feeding.
• There's no cure for HIV/AIDS, but medications can dramatically slow
the progression of the disease. These drugs have reduced AIDS deaths
in many developed nations.

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Some viral disease(continued)
• Polio, or poliomyelitis, is a disabling and life-threatening disease
caused by the poliovirus.
• The virus spreads from person to person and can infect a person’s
spinal cord, causing paralysis (can’t move parts of the body).
• Prevention & Treatment
• There are two types of vaccine that can prevent polio:
– Inactivated poliovirus vaccine (IPV) given as an injection in the
leg or arm, depending on the patient’s age.
– Oral poliovirus vaccine (OPV) is still used throughout much of
the world.

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Anti viral drugs
• Antiviral drugs are prescription medicines that fight against viruses in
the body. Key Points about antiviral drugs:
– Able to enter the cells infected with virus
– Interfere with viral nucleic acid synthesis and/or regulation
– Some agent interfere with virus ability to bind with cell
– Some agents stimulate the body's immune system
• Mechanism of Action (in combination or single action)
– Inhibit viral attachment
– Prevent genetic copying of virus
– Prevent viral protein production, vital for reproduction of virus

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Anti viral drugs (continued)

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Some Protozoan Diseases
• Giardia Protozoa
• Giardia are flagellate protozoa that cause giardiasis. The parasites
enter the body through food or water that has been contaminated by
feces of infected people or animals.
• The protozoa attach to the lining of the host’s small intestine, where
they prevent the host from fully absorbing nutrients.
• They may also cause diarrhea, abdominal pain, and fever. A picture of
a Giardia protozoan opens this concept.

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Some Protozoan Diseases(continued)
• Plasmodium Protozoa
• Plasmodium protozoa cause malaria. The parasites are spread by a
mosquito vector.
• Parasites enter a host’s blood through the bite of an infected mosquito.
The parasites infect the host’s red blood cells, causing symptoms such
as fever, joint pain, anemia, and fatigue.
• Malaria is common in tropical and subtropical climates throughout the
world
• malaria is one of the most common infectious diseases on the planet. It
kills several million people each year

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Water Microbiology

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Introduction to Water Microbiology
• Water microbiology is concerned with the microorganisms that live in
water, or can be transported from one habitat to another by water.
• Water can support the growth of many types of microorganisms. This
can be advantageous. For example, the chemical activities of certain
strains of yeasts provide us with beer and bread. As well, the growth of
some bacteria in contaminated water can help digest the poisons from
the water.

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Water microbiology and Diseases
• However, the presence of other disease causing microbes in water is
unhealthy and even life threatening. For example, bacteria that live in
the intestinal tracts of humans and other warm blooded animals, such
as Escherichia coli, Salmonella, Shigella, and Vibrio, can contaminate
water if feces enters the water. Contamination of drinking water with
a type of Escherichia coli known as O157:H7 can be fatal.
• The intestinal tract of warm-blooded animals also contains viruses that
can contaminate water and cause disease. Examples include rotavirus,
enteroviruses, and coxsackievirus.

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Microorganisms found in fresh and salt water
• Many microorganisms are found naturally in fresh
and saltwater. These include bacteria, cyanobacteria, protozoa, algae
and tiny animals such as rotifers. These can be important in the food
chain that forms the basis of life in the water.
• For example, the microbes called cyanobacteria can convert
the energy of the sun into the energy it needs to live. The plentiful
numbers of these organisms in turn are used as food for other life.
• Saltwater presents a different environment to microorganisms. The
higher salt concentration, higher pH, and lower nutrients, relative to
freshwater, are lethal to many microorganisms. But, salt loving
(halophilic) bacteria abound near the surface, and some bacteria that
also live in freshwater are plentiful (i.e., Pseudomonas and Vibrio)

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Treatment of Water
• Chemicals such as chlorine or chlorine derivatives has been a popular
means of killing bacteria such as Escherichia coli in water since the
early decades of the twentieth century.
• Other bacteria-killing treatments that are increasingly becoming
popular include the use of a gas called ozone and the disabling of the
microbe's genetic material by the use of ultraviolet light.
• Microbes can also be physically excluded form the water by passing
the water through a filter. Modern filters have holes in them that are so
tiny that even particles as miniscule as viruses can be trapped.

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Thank You