Bacteria - definition, what is, types and list of bacteria

Bacteria - definition, what is, types and list of bacteria - picture

FragmentHealth.com » Infectious Diseases » Bacteria definition

What is bacteria and definition of bacteria

Bacteria - single-cell microorganisms (microbes). Bacteria are the most ancient and primitive life forms known, with fossils dating back more than 3 billion years. A bacterium’s structure is very simple, consisting of a rigid cell wall that supports and contains the cytoplasm, fragments of RNA, and a single strand of DNA within a nonencapsulated (unbordered) nucleus. Though bacteria are capable of independent existence, most require a symbiotic relationship with a host organism. The bacteria provide needed functions for the host in exchange for NUTRIENTS and safe haven.

Types of bacteria

Many types of bacteria exist in and on the body in just such a symbiotic partnership; these are part of the body’s NORMAL FLORA. Bacteria in the gastrointestinal tract digest food, for example. Bifidobacterium bifidum, Lactobacillus acidophilus, and Saccaromyces boulardii are some of the more abundant bacterial families that reside in the small intestine. However, when normal flora bacteria are able to establish themselves in tissues other than their natural habitat or their numbers become abundant, they cause INFECTION. Escherichia coli, for example, are abundant normal flora in the COLON, where they work to prepare the residue of digestion for elimination from the body. E. coli also synthesize VITAMIN K, which is essential for COAGULATION (BLOOD clotting). When E. coli escape from their habitat, however, they cause infections such as VAGINITIS or URINARY TRACT INFECTION (UTI).

THE “BAD” E. COLI: O157:H7

The bacterial family Escherichia coli is extensive and ubiquitous-its many strains live in the gastrointestinal systems of nearly all animals. E. coli O157:H7, NORMAL FLORA in cattle, is a family member of great notoriety for the potential of severe illness it presents in people. The toxin this strain releases can destroy red BLOOD cells in such volume that the KIDNEYS fail, a condition called HEMOLYTIC UREMIC SYNDROME. E. coli O157:H7 enters the human food chain as a foodborne illness.

Bacteria that cause infection are pathogens. Most pathogenic bacteria exist in the natural environment, they are harmful to human health, and the IMMUNE SYSTEM establishes mechanisms to stop, contain, or attack them should they enter the body. Bacteria can cause infection and illness by destroying the cells they invade or by releasing toxins. ANTIBIOTIC MEDICATIONS treat bacterial infections.

Traditional classification systems view bacteria according to their physical (morphologic) characteristics because these are the traits perceptible with the use of a microscope, the first tool available for viewing microbes. These characteristics provide basic information about the particular bacterial family that is important to doctors when choosing antibiotic medications to treat bacterial infections. Methods made available through advances in molecular medicine during the latter years of the 20th century, such as ribosomal analysis and DNA sequencing, allow improved understanding of how bacteria function both to support health and to cause illness.

ILLNESSES CAUSED BY BACTERIAL INFECTION
ABSCESS ANTHRAX
APPENDICITIS bacterial MENINGITIS
BOTULISM CAMPYLOBACTERIOSIS
CHLAMYDIA CHOLERA
COLD SORE CONJUNCTIVITIS
DIPHTHERIA EPIGLOTTITIS
FOLLICULITIS FURUNCLE
GONORRHEA HERPES ZOSTER
INFECTIOUS ARTHRITIS LEGIONNAIRES’ DISEASE
LISTERIOSIS LYME DISEASE
MASTOIDITIS NECROTIZING FASCIITIS
ORBITAL CELLULITIS OSTEOMYELITIS
PERICARDITIS PERITONSILLAR ABSCESS
PNEUMOCOCCAL PNEUMONIA RHEUMATIC HEART DISEASE
ROCKY MOUNTAIN SPOTTED FEVER SCARLET FEVER
SEPTICEMIA STAPHYLOCOCCAL SCALDED SKIN SYNDROME
STREP THROAT TYPHOID FEVER
SYPHILIS TUBERCULOSIS

See also CELL STRUCTURE AND FUNCTION; CHILDHOOD DISEASES; ESCHERICHIA

Resource: Facts On File Encyclopedia Of Health And Medicine

Each atricle being rated on a scale of 1 to 5 stars.
Please rate this article
Article Rating: 1,7 stars of 5

Discussion and opinions:

Insert your opinion:

Tweet this page

Other Articles

Virus (infection) definition and immune system

Infectious Diseases |

What is a virus - definition Virus - an infectious PATHOGEN that must invade a host cell to replicate, technically called an obligate intracellular PARASITE. A virus is a particle of living material that contains an inner core of nucleic acid (DNA or RNA), called the genome, encased in an outer shell of protein, called a capsid. Some viruses contain a

Adenovirus (virus) - infection and symptoms

Infectious Diseases |

A VIRUS family that causes INFECTION of mucous membrane tissues throughout the body. Adenoviruses are responsible for a wide range of illness including upper respiratory infection, viral CONJUNCTIVITIS, GASTROENTERITIS, and URINARY TRACT INFECTION (UTI). These infections primarily affect children age 10 and younger. Infection with one adenovirus confers

Amebiasis treatment and symptoms

Infectious Diseases |

A parasitic INFECTION of the gastrointestinal tract. The PARASITE responsible is Entamoeba histolytica, a single-cell organism (an ameba) that enters the body by drinking water or eating food that contains E. histolytica in cyst form. The cyst is a protective encasing within which the ameba may sustain itself in a dormant stage for weeks to months outside a

Antibiotic medications - side effects

Infectious Diseases |

Antibiotic medications - Drugs that kill BACTERIA and certain other microorganisms. Antibiotic medications are the mainstay of treatment for bacterial INFECTION. Broad-spectrum antibiotics are capable of killing numerous types of bacteria; narrowspectrum antibiotics kill specific types or strains of bacteria. There are seven primary classifications of

Antifungal medications and treatment

Infectious Diseases |

Drugs that kill fungi (yeast). Antifungal medications are available for topical or systemic treatment. Some fungal infections require both. Antifungal medications work through various mechanisms to interfere with the ability of fungi to survive or reproduce. Broadspectrum antifungal medications are effective for treating a variety of fungal infections;

Antiviral medications and viral infection

Infectious Diseases |

Antiviral medications - medications to shorten the course and lessen the severity of illness due to viral INFECTION as well as reduce viral shedding to minimize contagiousness. Some antiviral medications are able to prevent viral infection from developing after exposure to the VIRUS. Antiviral medications mark a fine line because they must destroy viruses

What is Anthrax

Infectious Diseases |

Anthrax (disease) - an illness resulting from INFECTION with the bacterium Bacillus anthracis. Anthrax is a naturally occurring infection among wild and domestic livestock (such as cows, sheep, goats, and antelope). Anthrax is rare in people in the United States, though more common in people who live, work, or travel to countries where anthrax is more

Babesiosis disease Babesia microti and symptoms

Infectious Diseases |

An illness that results from INFECTION with the parasitic protozoan Babesia microti. Most people who have babesiosis do not have symptoms; the infection causes illness primarily in people who are IMMUNOCOMPROMISED or who have had SPLENECTOMY (surgical removal of the SPLEEN). The bite of the Ixodes tick, found in the northeastern United States, is the mode

Bacteria - definition, what is, types and list of bacteria

Infectious Diseases |

What is bacteria and definition of bacteria Bacteria - single-cell microorganisms (microbes). Bacteria are the most ancient and primitive life forms known, with fossils dating back more than 3 billion years. A bacterium’s structure is very simple, consisting of a rigid cell wall that supports and contains the cytoplasm, fragments of RNA, and a single

What is Botulism

Infectious Diseases |

What is Botulism Botulism is a potentially life-threatening illness resulting from INFECTION with the anaerobic bacterium Clostridium botulinum. The BACTERIA are naturally present in soil, where they encase themselves in spores. In the body, the bacteria release a toxin that blocks the release of acetylcholine, a NEUROTRANSMITTER that facilitates NERVE