human intestinal spirochetosis, also intestinal spirochetes, colonic spirochetosis and colonic spirochetes, is an infection of the colonic-type mucosa with spirochete microorganisms.

Pseudomonas infection refers to a disease caused by one of the species of the genus "Pseudomonas".

"Pseudomonas sp. KUMS3" could be considered

as an opportunistic pathogen, which can survive on the

fish surface or in water or in the gut and may cause disease

when unfavorable conditions develop.

"P. aeruginosa" is an opportunistic human pathogen, most commonly affecting immunocompromised patients, such as those with cystic fibrosis or AIDS. Infection can affect many different parts of the body, but infections typically target the respiratory tract (e.g. patients with CF or those on mechanical ventilation), causing bacterial pneumonia. In a surveillance study between 1986 and 1989, P. aeruginosa was the third leading cause of all nosocomial infections, and specifically the number one leading cause of hospital-acquired pneumonia and third leading cause of hospital-acquired UTI. Treatment of such infections can be difficult due to multiple antibiotic resistance, and in the United States, there was an increase in MDRPA (Multidrug-resistant "Pseudomonas aeruginosa") resistant to ceftazidime, ciprofloxacin, and aminoglycosides, from 0.9% in 1994 to 5.6% in 2002.

"P. oryzihabitans" can also be a human pathogen, although infections are rare. It can cause peritonitis, endophthalmitis, septicemia and bacteremia. Similar symptoms although also very rare can be seen by infections of "P. luteola".

"P. plecoglossicida" is a fish pathogenic species, causing hemorrhagic ascites in the ayu ("Plecoglossus altivelis"). "P. anguilliseptica" is also a fish pathogen.

Due to their hemolytic activity, even non-pathogenic species of "Pseudomonas" can occasionally become a problem in clinical settings, where they have been known to infect blood transfusions.

Human intestinal spirochetosis is caused by "Brachyspira pilosicoli" and "Brachyspira aalborgi". Porcine and avian intestinal spirochetosis are caused by "Brachyspira pilosicoli".

An opportunistic infection is an infection caused by pathogens (bacteria, viruses, fungi, or protozoa) that take advantage of an opportunity not normally available, such as a host with a weakened immune system, an altered microbiota (such as a disrupted gut flora), or breached integumentary barriers. Many of these pathogens do not cause disease in a healthy host that has a normal immune system. However, a compromised immune system, a penetrating injury, or a lack of competition from normal commensals presents an opportunity for the pathogen to infect.

Dysentery is a type of gastroenteritis that results in diarrhea with blood. Other symptoms may include fever, abdominal pain, and a feeling of incomplete defecation.

It is caused by several types of infections such as bacteria, viruses, parasitic worms, or protozoa. The mechanism is an inflammatory disorder of the intestine, especially of the colon.

The most common form of dysentery is bacillary dysentery, which is typically a mild illness, causing symptoms normally consisting of mild stomach pains and frequent passage of stool or diarrhea. Symptoms normally present themselves after one to three days, and are usually no longer present after a week. The frequency of urges to defecate, the large volume of liquid feces passed, and the presence of mucus, pus, and blood depends on the pathogen causing the disease. Temporary lactose intolerance can occur, as well. In some caustic occasions severe abdominal pain, fever, shock, and delirium can all be symptoms.

In extreme cases, dysentery patients may pass more than one litre of fluid per hour. More often, individuals will complain of nausea, abdominal pain, and frequent watery and usually foul-smelling diarrhea, accompanied by mucus, blood, rectal pain, and fever. Vomiting, rapid weight-loss, and generalized muscle aches sometimes also accompany dysentery. On rare occasions, the amoebic parasite will invade the body through the bloodstream and spread beyond the intestines. In such cases, it may more seriously infect other organs such as the brain, lungs, and most commonly the liver.

Most infections are light and asymptomatic. In heavy infections, symptoms can include abdominal pain, chronic diarrhea, anemia, ascites, toxemia, allergic responses, sensitization caused by the absorption of the worms' allergenic metabolites (may eventually cause death of patient), and intestinal obstruction.

Bacteremia is the presence of bacteria in the bloodstream that are alive and capable of reproducing. It is a type of bloodstream infection. Bacteremia is defined as either a primary or secondary process. In primary bacteremia, bacteria have been directly introduced into the bloodstream. Injection drug use may lead to primary bacteremia. In the hospital setting, use of blood vessel catheters contaminated with bacteria may also lead to primary bacteremia. Secondary bacteremia occurs when bacteria have entered the body at another site, such as the cuts in the skin, or the mucous membranes of the lungs (respiratory tract), mouth or intestines (gastrointestinal tract), bladder (urinary tract), or genitals. Bacteria that have infected the body at these sites may then spread into the lymphatic system and gain access to the bloodstream, where further spread can occur.

Bacteremia may also be defined by the timing of bacteria presence in the bloodstream: transient, intermittent, or persistent. In transient bacteremia, bacteria are present in the bloodstream for minutes to a few hours before being cleared from the body, and the result is typically harmless in healthy people. This can occur after manipulation of parts of the body normally colonized by bacteria, such as the mucosal surfaces of the mouth during teeth brushing, flossing, or dental procedures, or instrumentation of the bladder or colon. Intermittent bacteremia is characterized by periodic seeding of the same bacteria into the bloodstream by an existing infection elsewhere in the body, such as an abscess, pneumonia, or bone infection, followed by clearing of that bacteria from the bloodstream. This cycle will often repeat until the existing infection is successfully treated. Persistent bacteremia is characterized by the continuous presence of bacteria in the bloodstream. It is usually the result of an infected heart valve, a central line-associated bloodstream infection (CLABSI), an infected blood clot (suppurative thrombophlebitis), or an infected blood vessel graft. Persistent bacteremia can also occur as part of the infection process of typhoid fever, brucellosis, and bacterial meningitis. Left untreated, conditions causing persistent bacteremia can be potentially fatal.

Bacteremia is clinically distinct from sepsis, which is a condition where the blood stream infection is associated with an inflammatory response from the body, often causing abnormalities in body temperature, heart rate, breathing rate, blood pressure, and white blood cell count.

Microscopic identification of eggs, or more rarely of the adult flukes, in the stool or vomitus is the basis of specific diagnosis. The eggs are indistinguishable from those of the very closely related "Fasciola hepatica" liver fluke, but that is largely inconsequential since treatment is essentially identical for both.

Bacteremia (also bacteraemia) is the presence of bacteria in the blood. Blood is normally a sterile environment, so the detection of bacteria in the blood (most commonly accomplished by blood cultures) is always abnormal. It is distinct from sepsis, which is the host response to the bacteria.

Bacteria can enter the bloodstream as a severe complication of infections (like pneumonia or meningitis), during surgery (especially when involving mucous membranes such as the gastrointestinal tract), or due to catheters and other foreign bodies entering the arteries or veins (including during intravenous drug abuse). Transient bacteremia can result after dental procedures or brushing of teeth.

Bacteremia can have several important health consequences. The immune response to the bacteria can cause sepsis and septic shock, which has a high mortality rate. Bacteria can also spread via the blood to other parts of the body (which is called hematogenous spread), causing infections away from the original site of infection, such as endocarditis or osteomyelitis. Treatment for bacteremia is with antibiotics, and prevention with antibiotic prophylaxis can be given in high risk situations.

Multiple drug resistance (MDR), multidrug resistance or multiresistance is antimicrobial resistance shown by a species of microorganism to multiple antimicrobial drugs. The types most threatening to public health are MDR bacteria that resist multiple antibiotics; other types include MDR viruses, fungi, and parasites (resistant to multiple antifungal, antiviral, and antiparasitic drugs of a wide chemical variety). Recognizing different degrees of MDR, the terms extensively drug resistant (XDR) and pandrug-resistant (PDR) have been introduced. The definitions were published in 2011 in the journal "Clinical Microbiology and Infection" and are openly accessible.

Most infected people, about 90%, are asymptomatic, but this disease has the potential to make the sufferer dangerously ill. It is estimated that about 40,000 to 100,000 people worldwide die annually due to amoebiasis.

Infections can sometimes last for years. Symptoms take from a few days to a few weeks to develop and manifest themselves, but usually it is about two to four weeks. Symptoms can range from mild diarrhea to severe dysentery with blood and mucus. The blood comes from lesions formed by the amoebae invading the lining of the large intestine. In about 10% of invasive cases the amoebae enter the bloodstream and may travel to other organs in the body. Most commonly this means the liver, as this is where blood from the intestine reaches first, but they can end up almost anywhere in the body.

Onset time is highly variable and the average asymptomatic infection persists for over a year. It is theorized that the absence of symptoms or their intensity may vary with such factors as strain of amoeba, immune response of the host, and perhaps associated bacteria and viruses.

In asymptomatic infections the amoeba lives by eating and digesting bacteria and food particles in the gut, a part of the gastrointestinal tract. It does not usually come in contact with the intestine itself due to the protective layer of mucus that lines the gut. Disease occurs when amoeba comes in contact with the cells lining the intestine. It then secretes the same substances it uses to digest bacteria, which include enzymes that destroy cell membranes and proteins. This process can lead to penetration and digestion of human tissues, resulting first in flask-shaped ulcers in the intestine. "Entamoeba histolytica" ingests the destroyed cells by phagocytosis and is often seen with red blood cells (a process known as erythrophagocytosis) inside when viewed in stool samples. Especially in Latin America, a granulomatous mass (known as an amoeboma) may form in the wall of the ascending colon or rectum due to long-lasting immunological cellular response, and is sometimes confused with cancer.

"Theoretically, the ingestion of one viable cyst can cause an infection."

Amoebiasis, also known amoebic dysentery, is an infection caused by any of the amoebas of the "Entamoeba" group. Symptoms are most common during infection by "Entamoeba histolytica". Amoebiasis can be present with no, mild, or severe symptoms. Symptoms may include abdominal pain, diarrhea, or bloody diarrhea. Complications can include inflammation of the colon with tissue death or perforation, which may result in peritonitis. People affected may develop anemia due to loss of blood.

Cysts of "Entamoeba" can survive for up to a month in soil or for up to 45 minutes under fingernails. Invasion of the intestinal lining can cause bloody diarrhea. If the parasite reaches the bloodstream it can spread through the body, most frequently ending up in the liver where it can cause amoebic liver abscesses. Liver abscesses can occur without previous diarrhea. Diagnosis is typical by stool examination using a microscope, but may not reliably exclude infection or separate between specific types. An increased white blood cell count may be present in severe cases. The most accurate test is finding specific antibodies in the blood, but it may remain positive following treatment. Bacterial colitis can result in similar symptoms.

Prevention of amoebiasis is by improved sanitation, including separating food and water from faeces. There is no vaccine. There are two treatment options depending on the location of the infection. Amoebiasis in tissues is treated with either metronidazole, tinidazole, nitazoxanide, dehydroemetine or chloroquine, while luminal infection is treated with diloxanide furoate or iodoquinoline. Effective treatment against all stages of the disease may require a combination of medications. Infections without symptoms do not require treatment but infected individuals can spread the parasite to others and treatment can be considered. Treatment of other "Entamoeba" infections apart from "E. histolytica" is not needed.

Amoebiasis is present all over the world. About 480 million people are infected with amoebiasis and this results in the death of between 40,000–110,000 people a year. Most infections are now believed due to "E. dispar". "E. dispar" is more common in certain areas and symptomatic cases may be less common than previously reported. The first case of amoebiasis was documented in 1875 and in 1891 the disease was described in detail, resulting in the terms "amoebic dysentery" and "amoebic liver abscess". Further evidence from the Philippines in 1913 found that upon swallowing cysts of "E. histolytica" volunteers developed the disease.

Signs and symptoms depend on the type of infection. Intestinal parasites produce a variety of symptoms in those affected, most of which manifest themselves in gastrointestinal complications and general weakness. Gastrointestinal complications include diarrhea, nausea, dysentery, and abdominal pain. These symptoms negatively impact nutritional status, including decreased absorption of micronutrients, loss of appetite, weight loss, and intestinal blood loss that can often result in anemia. It may also cause physical and mental disabilities, delayed growth in children, and skin irritation around the anus and vulva.

Immunodeficiency or immunosuppression can be caused by:

- Malnutrition

- Fatigue

- Recurrent infections

- Immunosuppressing agents for organ transplant recipients

- Advanced HIV infection

- Chemotherapy for cancer

- Genetic predisposition

- Skin damage

- Antibiotic treatment leading to disruption of the physiological microbiome, thus allowing some microorganisms to outcompete others and become pathogenic (e.g. disruption of intestinal flora may lead to "Clostridium difficile" infection

- Medical procedures

- Pregnancy

- Ageing

- Leukopenia (i.e. neutropenia and lymphocytopenia)

The lack of or the disruption of normal vaginal flora allows the proliferation of opportunistic microorganisms and will cause the opportunistic infection - bacterial vaginosis.

A amoebic liver abscess is a type of liver abscess caused by amebiasis. It is the involvement of liver tissue by trophozoites of the organism "Entamoeba histolytica" and of is abscess due to necrosis.

A liver abscess is a pus-filled mass inside the liver. Common causes are abdominal conditions such as appendicitis or diverticulitis due to haematogenous spread through the portal vein.

Symptoms

- Pain right hypochondrium referred to right shoulder

- Pyrexia (100.4 F)

- Profuse sweating and rigors

- Loss of weight

- Earthy complexion

Signs

- Pallor

- Tenderness and rigidity in right hypochondrium

- Palpable liver

- tenderness

- Basal lung signs

Adult flukes are known to be quite harmless, as they do not attack on the host tissue. It is the immature flukes which are most damaging as they get attached to the intestinal wall, literally and actively sloughing off of the tissue. This necrosis is indicated by haemorrhage in faeces, which in turn is a sign of severe enteritis. Under such condition the animals become anorexic and lethargic. It is often accompanied by pronounced diarrhoea, dehydration, oedema, polydipsia, anaemia, listlessness and weight loss. In sheep profuse diarrhoea usually develops two to four weeks after initial infection. If infection is not properly attended death can ensue within 20 days, and in a farm mortality can be very high. In fact there are intermittent reports of mortality as high as 80% among sheep and cattle. Sometimes chronic form is also seen with severe emaciation, anaemia, rough coat, mucosal oedema, thickened duodenum and oedema in the sub maxillary space. The terminally sick animals lie prostrate on the ground, completely emaciated until they die. In buffalos, severe haemorrhage was found to be associated with liver cirrhosis and nodular hepatitis.

Amphistomiasis or paramphistomiasis (alternatively spelled amphistomosis or paramphistomosis) is a parasitic disease of livestock animals, more commonly of cattle and sheep, and humans caused by immature helminthic flatworms belonging to the order Echinostomida. The term amphistomiasis is used for broader connotation implying the disease inflicted by members of Echinostomida including the family Paramphistomidae/Gastrodiscidae (to be precise, the species "Gastrodiscoides hominis"); whereas paramphistomiasis is restricted to that of the members of the family Paramphistomatidae only. "G. discoides" and "Watsonius watsoni" are responsible for the disease in humans, while most paramphistomes are responsible in livestock animals, and some wild mammals. In livestock industry the disease causes heavy economic backlashes due to poor production of milk, meat and wool.

An intestinal parasite infection is a condition in which a parasite infects the gastro-intestinal tract of humans and other animals. Such parasites can live anywhere in the body, but most prefer the intestinal wall.

Routes of exposure and infection include ingestion of undercooked meat, drinking infected water, fecal-oral transmission and skin absorption.

Some types of helminths and protozoa are classified as intestinal parasites that cause infection—those that reside in the intestines. These infections can damage or sicken host (humans or other animals). If the intestinal parasite infection is caused by helminths, the infection is called helminthiasis.

Major bacterial causes of liver abscess include the following:

- "Streptococcus" species (including "Enterococcus")

- "Escherichia" species

- "Staphylococcus" species

- "Klebsiella" species (Higher rates in the Far East)

- Anaerobes (including "Bacteroides" species)

- "Pseudomonas" species

- "Proteus" species

However, as noted above, many cases are polymicrobial.

Pseudomonas aeruginosa is a common bacterium that can cause disease in animals, including humans. It is found in soil, water, skin flora, and most man-made environments throughout the world. It thrives not only in normal atmospheres, but also in hypoxic atmospheres, and has, thus, colonized many natural and artificial environments. It uses a wide range of organic material for food; in animals, the versatility enables the organism to infect damaged tissues or those with reduced immunity. The symptoms of such infections are generalized inflammation and sepsis. If such colonizations occur in critical body organs, such as the lungs, the urinary tract, and kidneys, the results can be fatal. Because it thrives on most surfaces, this bacterium is also found on and in medical equipment, including catheters, causing cross-infections in hospitals and clinics. It is implicated in hot-tub rash. It is also able to decompose hydrocarbons and has been used to break down tarballs and oil from oil spills.

Noma neonatorum is a cutaneous condition, a manifestation of infection, usually "Pseudomonas aeruginosa" septicemia, and has been reported almost exclusively in developing countries.

New or progressive infiltrate on the chest X-ray with one of the following:

- Fever > 37.8 °C (100 °F)

- Purulent sputum

- Leukocytosis > 10,000 cells/μl

In an elderly person, the first sign of hospital-acquired pneumonia may be mental changes or confusion.

Other symptoms may include:

- A cough with greenish or pus-like phlegm (sputum)

- Fever and chills

- General discomfort, uneasiness, or ill feeling (malaise)

- Loss of appetite

- Nausea and vomiting

- Sharp chest pain that gets worse with deep breathing or coughing

- Shortness of breath

- Decreased blood pressure and fast heart rate