What are 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 vast majority of
bacteria are harmless to people and some strains are even beneficial. In the
human gastrointestinal tract, good bacteria aid in digestion and produce
vitamins. They also help with immunity, making the body less hospitable to bad
bacteria and other harmful pathogens. When considering all the strains of bacteria
that exist, relatively few are capable of making people sick.
What Is a 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. 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.
Bacteria vs. 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.
Instead, viruses reproduce by infecting a host and using the host's DNA repair
and replication systems to make copies of itself.
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). 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
Bacterial skin
infections are usually caused by gram-positive strains of Staphylococcus and
Streptococcus or other organisms. Common bacterial skin infections include:
·
Cellulitis causes a painful, red infection that is
usually warm to the touch. Cellulitis occurs most often on the legs, but it can
appear anywhere on the body.
·
Folliculitis is an infection of the hair follicles that
causes red, swollen bumps that look like pimples. Improperly treated pools or
hot tubs can harbor bacteria that cause folliculitis.
·
Impetigo causes oozing sores, usually in
preschool-aged children. The bullous form of impetigo causes large blisters
while the non-bullous form has a yellow, crusted appearance.
·
Boils are deep skin infections that start in
hair follicles. Boils are firm, red, tender bumps that progress until pus
accumulates underneath the skin.
Bacterial skin
infections are treated with oral or topical antibiotics depending on the strain
causing the infection.
Foodborne Bacterial
Infections
Bacterial infections are
one cause of foodborne illness. 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. Bacteria that cause food poisoning include:
·
Campylobacter
jejuni (C. jejuni) is a diarrheal
illness often accompanied by cramps and fever.
·
Clostridium
botulinum (C. botulinum) is
a potentially life-threatening bacterium that
Sexually Transmitted
Bacterial Infections
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. Common STDs caused by bacterial infections
include:
·
Chlamydia is an infection in men and women caused by
an organism called Chlamydia trachomatis. Chlamydia increases the risk of
pelvic inflammatory disease (PID) in women.
·
Gonorrhea, also known as "clap" and "the
drip," is caused by Neisseria gonorrhoeae. Men and women can be infected.
Gonorrhea also increases the risk of pelvic inflammatory disease (PID) in
women.
·
Syphilis can affect men and women and is caused by
the bacteria Treponema pallidum. Untreated, syphilis is potentially very
dangerous and can even be fatal.
·
Bacterial vaginosis, which causes an overgrowth of
pathogenic bacteria in the vagina (the CDC does not consider this a STD; see
second text reference).
Other Bacterial
Infections
Harmful bacteria can
affect almost any area of the body. Other types of bacterial infections
include:
·
Bacterial
meningitis is a severe
infection of the meninges, the lining of the brain.
·
Otitis
media is the official
name for an infection or inflammation of the middle ear. Both bacteria and
viruses can cause ear infections, which commonly occur in babies and small
children.
·
Urinary
tract infection (UTI) is a bacterial
infection of the bladder, urethra, kidneys, or ureters.
·
Respiratory
tract infections include sore
throat, bronchitis, sinusitis, and pneumonia. Bacteria or viruses may be
responsible for respiratory tract infections. Tuberculosis is a type of
bacterial lower respiratory tract infection.
Antibiotics
Antibiotics
are medications that fight bacterial infections. They work by disrupting the
processes necessary for bacterial cell growth and proliferation. It's important
to take antibiotics exactly as prescribed. Failure to do so could make a
bacterial infection worse. Antibiotics don't treat viruses, but they're
sometimes prescribed in viral illnesses to help prevent a "secondary
bacterial infection." Secondary infections occur when someone is in a
weakened or compromised state due to an existing illness.
Antibiotic Resistance
Overuse
and misuse of antibiotics has led to a rise in antibiotic resistance.
Antibiotic resistance occurs when bacteria are no longer sensitive to a
medication that should eliminate an infection. Antibiotic-resistant bacterial
infections are potentially very dangerous and increase the risk of death. About
2 million people in the U.S. suffer from antibiotic resistant infections each
year and 23,000 die due to the condition. The CDC estimates 14,000 deaths alone
are due to Clostridium difficile (C. difficile) infections that occur because
of antibiotic suppression of other bacteria allow C.difficile to proliferate.
Most deaths due to antibiotic resistant infections occur in hospitalized
patients and those who are in nursing homes.
Good Bacteria and Probiotics
Beneficial bacteria live in the
human gastrointestinal (GI) tract and play an important role in digestion and
immunity. Most people know it's smart to eat yogurt after completing a course
of antibiotics to repopulate the GI tract with helpful bacteria that were wiped
out from the antibiotics.
Some studies have shown
probiotics can shorten the duration of infectious diarrhea. They may also
reduce the risk of developing diarrheal illness due to antibiotic use.
Probiotics seem to reduce gas, bloating, and abdominal pain associated with
irritable bowel syndrome (IBS). Ongoing research seeks to determine the types
and dosages of bacteria that are most beneficial to human health.
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