Exogenous bacteria

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Exogenous bacteria are microorganisms introduced to closed biological systems from the external world.[ citation needed ] They exist in aquatic and terrestrial environments, as well as the atmosphere. Microorganisms in the external environment have existed on Earth for 3.5 billion years. [1] Exogenous bacteria can be either benign or pathogenic. Pathogenic exogenous bacteria can enter a closed biological system and cause disease such as Cholera, which is induced by a waterborne microbe that infects the human intestine. [2] Exogenous bacteria can be introduced into a closed ecosystem as well, and have mutualistic benefits for both the microbe and the host. [1] A prominent example of this concept is bacterial flora, which consists of exogenous bacteria ingested and endogenously colonized during the early stages of life. [3] Bacteria that are part of normal internal ecosystems, also known as bacterial flora, are called Endogenous Bacteria. A significant amount of prominent diseases are induced by exogenous bacteria such as gonorrhea, meningitis, tetanus, and syphilis. [4] Pathogenic exogenous bacteria can enter a host via cutaneous transmission, inhalation, and consumption. [5]

Contents

Difference with endogenous bacteria


Only a minority of bacteria species cause disease in humans; and many species colonize in the human body to create an ecosystem known as microbiota. Bacterial flora is endogenous bacteria, which is defined as bacteria that naturally reside in a closed system. [6] Disease can occur when microbes included in normal bacteria flora enter a sterile area of the body such as the brain or muscle. [6] This is considered an endogenous infection. A prime example of this is when the residential bacterium E. coli of the GI tract enters the urinary tract. [6] This causes a urinary tract infection. Infections caused by exogenous bacteria occurs when microbes that are noncommensal enter a host. [6] These microbes can enter a host via inhalation of aerosolized bacteria, ingestion of contaminated or ill-prepared foods, sexual activity, or the direct contact of a wound with the bacteria. [6]

Diseases

Waterborne and foodborne

Microbial ecosystems in aquatic environments depend on a variety of factors including pH, temperature, and light exposure. [1] Exogenous bacteria supported in specific aquatic environments can enter an host via consumption. Additionally, exogenous bacteria can enter a secondary host through an intermediate host such as insects and parasites. [7] Exogenous bacteria can also enter an enclosed ecosystem via ingestion of contaminated food. Food-borne diseases such as Salmonella poisoning are transmitted by food not properly cooked or by individuals infected with the pathogen.

Salmonella enterocolitis

One of the most common food-borne illnesses, Salmonella poisoning is caused by ingestion of unsanitary conditions during food preparation. [8] Salmonella can also be transmitted to humans via reptiles like turtles and iguanas, which are known carriers of pathogen. [8] Symptoms include chills, diarrhea [8] and fever.

Cholera

Cholera is a waterborne infection caused by the bacterium Vibrio cholerae, and is transmitted via food or water that is contaminated with fecal matter. [9] Vibrio cholerae releases a toxin that induces an increased amount of water in the small intestines. [9] Symptoms primarily observed include, watery diarrhea and vomiting that can cause dehydration and death if not treated. [9] An estimated 3-5 million cases of Cholera occur yearly around the world. [10] The exogenous bacteria derived infection is primarilyfound in Africa, Asia, as well as Central and South America. [9]

Campylobacter

Campylobacter infections are transmitted to a host via contaminated water and food, sexual activity, and interaction with infected animals. [5] Symptoms include diarrhea, cramping, and abdominal pain. [11] Campylobacter can cause disease in both humans and animals, and most human cases are induced by the species Campylobacter jejuni. [11]

Terrestrial exogenous bacteria

Of all the residential microbes found in soil, bacteria is the smallest and most abundant. [12] According to studies, there is an estimated 60,000 different types of bacteria that reside in the soil. [12] Terrestrial bacteria can characteristically be either aerobic or anaerobic, and some can be pathogenic if consumed by a host. [12]

Anthrax

Anthrax is a disease caused via a bacterium that resides in soil, and predominately affects animals more than humans. [8] Anthrax is also considered a zoonotic disease and is transmitted to humans via contact with an infected animal host. [5] The disease is caused by gram-positive Bacillus anthracis (B. anthracis) and is found globally. [5] B. anthracis can enter a host via cutaneous transmission, inhalation, and/or consumption. [5]

Botulism

Botulism is a rare disease caused by the bacterium Clostridium botulinum. This microbe is primarily found in the soil or untreated water. [13] Botulism spores can survive in unproperly canned or ill-prepared foods. [13] Even ingesting trace amounts of the spores can lead to severe poisoning that causes symptoms such as vomiting, nausea, and even paralysis. [13]

See also

Related Research Articles

A human pathogen is a pathogen that causes disease in humans.

<i>Bacillus cereus</i> Species of bacterium

Bacillus cereus is a Gram-positive rod-shaped bacterium commonly found in soil, food, and marine sponges. The specific name, cereus, meaning "waxy" in Latin, refers to the appearance of colonies grown on blood agar. Some strains are harmful to humans and cause foodborne illness due to their spore-forming nature, while other strains can be beneficial as probiotics for animals, and even exhibit mutualism with certain plants. B. cereus bacteria may be aerobes or facultative anaerobes, and like other members of the genus Bacillus, can produce protective endospores. They have a wide range of virulence factors, including phospholipase C, cereulide, sphingomyelinase, metalloproteases, and cytotoxin K, many of which are regulated via quorum sensing. B. cereus strains exhibit flagellar motility.

<i>Salmonella</i> Genus of bacteria

Salmonella is a genus of rod-shaped (bacillus) gram-negative bacteria of the family Enterobacteriaceae. The two known species of Salmonella are Salmonella enterica and Salmonella bongori. S. enterica is the type species and is further divided into six subspecies that include over 2,650 serotypes. Salmonella was named after Daniel Elmer Salmon (1850–1914), an American veterinary surgeon.

<i>Campylobacter</i> Genus of gram-negative bacteria

Campylobacter is a type of bacteria that can cause a diarrheal disease in people. Its name means "curved bacteria", as the germ typically appears in a comma or "s" shape. According to its scientific classification, it is a genus of gram-negative bacteria that is motile.

<span class="mw-page-title-main">Foodborne illness</span> Illness from eating spoiled food

Foodborne illness is any illness resulting from the contamination of food by pathogenic bacteria, viruses, or parasites, as well as prions, and toxins such as aflatoxins in peanuts, poisonous mushrooms, and various species of beans that have not been boiled for at least 10 minutes.

<i>Campylobacter jejuni</i> Species of bacterium

Campylobacter jejuni is a species of pathogenic bacteria that is commonly associated with poultry, and is also often found in animal feces. This species of microbe is one of the most common causes of food poisoning in Europe and in the US, with the vast majority of cases occurring as isolated events rather than mass outbreaks. Active surveillance through the Foodborne Diseases Active Surveillance Network (FoodNet) indicates that about 20 cases are diagnosed each year for each 100,000 people in the US, while many more cases are undiagnosed or unreported; the CDC estimates a total of 1.5 million infections every year. The European Food Safety Authority reported 246,571 cases in 2018, and estimated approximately nine million cases of human campylobacteriosis per year in the European Union. Campylobacter jejuni infections are increasing at an alarming rate in Europe, North America, and Australia. In Africa, Asia, and the Middle East, data indicates that C. jejuni infections are endemic.

<span class="mw-page-title-main">Campylobacteriosis</span> Medical condition

Campylobacteriosis is among the most common infections caused by a bacterium in humans, often as a foodborne illness. It is caused by the Campylobacter bacterium, most commonly C. jejuni. It produces an inflammatory, sometimes bloody, diarrhea or dysentery syndrome, and usually cramps, fever and pain.

<span class="mw-page-title-main">Salmonellosis</span> Infection caused by Salmonella bacteria

Salmonellosis is a symptomatic infection caused by bacteria of the Salmonella type. It is the most common disease to be known as food poisoning, these are defined as diseases, usually either infectious or toxic in nature, caused by agents that enter the body through the ingestion of food. In humans, the most common symptoms are diarrhea, fever, abdominal cramps, and vomiting. Symptoms typically occur between 12 hours and 36 hours after exposure, and last from two to seven days. Occasionally more significant disease can result in dehydration. The old, young, and others with a weakened immune system are more likely to develop severe disease. Specific types of Salmonella can result in typhoid fever or paratyphoid fever. Typhoid fever and paratyphoid fever are specific types of salmonellosis, known collectively as enteric fever, and are, respectively, caused by salmonella typhi and paratyphi bacteria, which are only found in humans. Most commonly, salmonellosis cases arise from salmonella bacteria from animals, and chicken is a major source for these infections.

<span class="mw-page-title-main">Staphylococcal enteritis</span> Medical condition

Staphylococcal enteritis is an inflammation that is usually caused by eating or drinking substances contaminated with staph enterotoxin. The toxin, not the bacterium, settles in the small intestine and causes inflammation and swelling. This in turn can cause abdominal pain, cramping, dehydration, diarrhea and fever.

<span class="mw-page-title-main">Lysogenic cycle</span> Process of virus reproduction

Lysogeny, or the lysogenic cycle, is one of two cycles of viral reproduction. Lysogeny is characterized by integration of the bacteriophage nucleic acid into the host bacterium's genome or formation of a circular replicon in the bacterial cytoplasm. In this condition the bacterium continues to live and reproduce normally, while the bacteriophage lies in a dormant state in the host cell. The genetic material of the bacteriophage, called a prophage, can be transmitted to daughter cells at each subsequent cell division, and later events can release it, causing proliferation of new phages via the lytic cycle.

<i>Campylobacter fetus</i> Species of bacterium

Campylobacter fetus is a rod-shaped, gram-negative species of bacteria within the genus Campylobacter of phylum Pseudomonadota. Identification of C. fetus species in infected animals or people is routinely performed by culture on blood or cefoperazone deoxycholate agar. Subspecies of C. fetus commonly causes reproductive disease in ruminants and gastrointestinal disease in humans. Transmission of C. fetus subspecies venerealis occurs mainly through venereal contact while transmission of C. fetus subspecies fetus occurs mainly through ingestion of bacteria in a contaminated environment. Infertility in cattle and abortion in sheep are common outcomes of infection associated with C. fetus subspecies venerealis and C. fetus subspecies fetus, respectively. Disease in humans occurs through zoonotic transmission of C. fetus mainly via ingestion of contaminated food or water sources. C. fetus can be diagnosed with polymerase chain reaction assays, enzyme linked immunosorbent assays and vaginal mucus agglutination testing. As vaccines are typically not efficient in preventing future spread, infected bulls are often culled. Human infections may be treated with erythromycin as antimicrobial resistance has been emerging for the fluoroquinolones.

Virulence factors are cellular structures, molecules and regulatory systems that enable microbial pathogens to achieve the following:

Indicator bacteria are types of bacteria used to detect and estimate the level of fecal contamination of water. They are not dangerous to human health but are used to indicate the presence of a health risk.

<span class="mw-page-title-main">Food microbiology</span> Study of the microorganisms that inhibit, create, or contaminate food

Food microbiology is the study of the microorganisms that inhabit, create, or contaminate food. This includes the study of microorganisms causing food spoilage; pathogens that may cause disease ; microbes used to produce fermented foods such as cheese, yogurt, bread, beer, and wine; and microbes with other useful roles, such as producing probiotics.

<span class="mw-page-title-main">Medical microbiology</span> Branch of medical science

Medical microbiology, the large subset of microbiology that is applied to medicine, is a branch of medical science concerned with the prevention, diagnosis and treatment of infectious diseases. In addition, this field of science studies various clinical applications of microbes for the improvement of health. There are four kinds of microorganisms that cause infectious disease: bacteria, fungi, parasites and viruses, and one type of infectious protein called prion.

Campylobacter upsaliensis is a gram-negative bacteria in the Campylobacter genus. C. upsaliensis is found worldwide, and is a common cause of campylobacteriosis in humans, as well as gastroenteritis in dogs and cats. Human infections are primarily associated with raw or undercooked meat and contaminated water sources, however there is some zoonotic risk associated with the spread from dogs and cats. C. upsaliensis primarily affects the gastrointestinal tract as it damages gastrointestinal epithelial cells. There are many methods for detecting C.upsaliensis including PCR and ELISA, however there is no current gold standard in detection techniques. Infection is typically self limiting, however there is antimicrobial therapy available.

<span class="mw-page-title-main">Oral microbiology</span>

Oral microbiology is the study of the microorganisms (microbiota) of the oral cavity and their interactions between oral microorganisms or with the host. The environment present in the human mouth is suited to the growth of characteristic microorganisms found there. It provides a source of water and nutrients, as well as a moderate temperature. Resident microbes of the mouth adhere to the teeth and gums to resist mechanical flushing from the mouth to stomach where acid-sensitive microbes are destroyed by hydrochloric acid.

<span class="mw-page-title-main">Pathogenic bacteria</span> Disease-causing bacteria

Pathogenic bacteria are bacteria that can cause disease. This article focuses on the bacteria that are pathogenic to humans. Most species of bacteria are harmless and are often beneficial but others can cause infectious diseases. The number of these pathogenic species in humans is estimated to be fewer than a hundred. By contrast, several thousand species are part of the gut flora present in the digestive tract.

The spoilage of meat occurs, if the meat is untreated, in a matter of hours or days and results in the meat becoming unappetizing, poisonous, or infectious. Spoilage is caused by the practically unavoidable infection and subsequent decomposition of meat by bacteria and fungi, which are borne by the animal itself, by the people handling the meat, and by their implements. Meat can be kept edible for a much longer time – though not indefinitely – if proper hygiene is observed during production and processing, and if appropriate food safety, food preservation and food storage procedures are applied.

The initial acquisition of microbiota is the formation of an organism's microbiota immediately before and after birth. The microbiota are all the microorganisms including bacteria, archaea and fungi that colonize the organism. The microbiome is another term for microbiota or can refer to the collected genomes.

References

  1. 1 2 3 Willey, Sherwood & Woolverton 2011, pp. 673–737.
  2. ↑ Willey, Sherwood & Woolverton 2011, pp. 964–72.
  3. ↑ Arumugam, Manimozhiyan; Raes, Jeroen; Pelletier, Eric; Le Paslier, Denis; Yamada, Takuji; Mende, Daniel R.; et al. (2011). "Enterotypes of the human gut microbiome". Nature. 473 (7346): 174–80. doi:10.1038/nature09944. PMC   3728647 . PMID   21508958.
  4. ↑ "Exogenous Bacteria." Bacteria Microbes. N.p., n.d. Web. 29 Apr 2012. <http://bacteria.health-tips-diseases.com/2009/02/exogenous-bacteria-and-disease.html>.
  5. 1 2 3 4 5 Willey, Sherwood & Woolverton 2011, pp. 964–5.
  6. 1 2 3 4 5 "Bacteria." ENotes. ENotes.com Inc., 2012. Web. 29 Apr 2012. <http://www.enotes.com/bacteria-reference/bacteria-171754>.
  7. ↑ "Mosquitoes and Disease." Prevention and Control. Illinois Department of Public Health, n.d. Web. 28 Apr 2012. <http://www.idph.state.il.us/envhealth/pcmosquitoes.htm>
  8. 1 2 3 4 MedlinePlus Encyclopedia : Salmonella enterocolitis
  9. 1 2 3 4 "Cholera." PubMed Health. US National Library of Medicine, n.d. Web. 28 Apr 2012. <https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001348/>.
  10. ↑ "Cholera." Media Centre. World Health Organization, n.d. Web. 28 Apr 2012. <http://www.who.int/mediacentre/factsheets/fs107/en/index.html>
  11. 1 2 "Campylobacter." National Center for Emerging and Zoonotic Infectious Diseases. Center for disease Control and Prevention, n.d. Web. 28 Apr 2012. <https://www.cdc.gov/nczved/divisions/dfbmd/diseases/campylobacter/>.
  12. 1 2 3 "Soil Bacteria." Soil Biology Basics. n. page. Web. 28 Apr. 2012.<http://www.dpi.nsw.gov.au/__data/assets/pdf_file/0017/41642/Soil_bacteria.pdf>.
  13. 1 2 3 "Botulism." PubMed Health. US National Library of Medicine, n.d. Web. 29 Apr 2012. <https://www.ncbi.nlm.nih.gov/pubmedhealth/PMH0001624/>.

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