Microbiology for the Healthcare Professional – Flashcards

• Caused by Salmonella enterica
• Gram negative
• Rod shaped, facultative anaerobic, nonsporing microorganism
• Animal/human
• Contaminated food
• Cause: typhoid fever, paratyphoid fever and foodborne illness
• Symptoms: diarrhea, fever and abdominal cramps
• Severity of illness results from amount of organisms ingested

• Leading cause C. jejuni
• Other causative agents: C. fetus and C. coli
• Gram negative
• Vibrioid or helical, motile microaerophiles
• Contaminated food, unchlorinated water and poor hygiene
• C. jejuni: fever, abdominal pain
• C. fetus: bloody diarrhea

• Is a member of the resident flora within the large intestine
• Helps breakdown food particles
• Helps with vitamin synthesis
• Normally harmless and useful by suppressing the growth of pathogenic organisms
• 5 virulent strains the lead to illness: Enterotoxigenic E. coli, Enteroinvasive E. coli, Enteropathogenic E. coli, Enteroagressive E. coli, and Enterohemorrhagic E. coli

• Contaminated food and water
• Organisms colonize in the small intestines
• A cause of infant and travelers diarrhea, found where sanitation is poor or underdeveloped countries
• Enterotoxins produced are heat-labile (LT) and/or heat-stable (ST) toxins
• Minor discomfort to sever, chloera-like symptoms

• Penetrates and multiplies in the epithelial cells of the colon, resulting in the destruction of these cells
• Symptoms are similar to those of Shigella dysentery (dysentery-like diarrhea) with fever
• Is an invasive organism but DOES NOT produce LT or ST toxins

• Similar to EIEC
• DOES NOT produce LT or ST toxins
• Has been reported that the organism produces an entertoxin similar to Shigella

• Accompanied by persistent diarrhea in young children
• In addition to its toxin (enteroaggregative ST-like toxins) 
• Also produces a hemolysin related to one made by strains of  E. coli commonly cause urinary tract infections

• Single strain
• Capable of causing massive destruction to the colon wall
• It can cause hemolytic uremia which can damage the kidney and eventually end up in death
• Produces large quantities of one or more related potent toxins
• Capable of producing severe damage to the intestinal lining
• Toxins are closely related to the toxins produced by Shigella dysenteriae and causes diarrhea with aboundant bloody discharge
• It is frequently life-threating because of its toxic effects on the kidneys (hemolytic uremia)

• Gram negative
• Facultatively anaerobic rod
• Y. entercolitica mostly affects young people with fever, diarrhea and right sided abdominal pain
• Sources are: untreated drinking water, contaminated food particularly pork

• Caused by Listeria monocytogenes
• Gram positive
• Non spore forming rod
• Factultatively anaerobic
• Can spread to  the bloodstream and the central nervous system
• Capacity to infect a variety of cells
• Contaminated food, soil, decaying plant matter, spoiled dairy products, found in some meats, and can be carried by animals

Bacterial food intoxication is an illness caused by the consumption of actual bacterial toxins

BOTULISM                                             BACILLUS

STAPHYLOCOCCAL                                  CHOLERA

Bacteria are the most common cause of foodborne illness, which can be caused by the bacteria, their toxins, or both. 

A bacterial infection occurs when a pathogen enters the GI tract, adheres, and multiplies.

Viruses causing gastroenteritis.

Viral gastroenteritis for the most part is rather mild. It can be harmful if rehydration isn't followed up with especially in children.;

Transmitted by the fecal-oral route, person-to-person contact or ingestion of contaminated foods and water.

• Contaminated food or water
• Vomiting, slight fever, watery diarrhea
• No antiviral treatment; fluid replacement
• World wide these viruses are the most common in infants and children leading to profound diarrheak; about 50% of children who develop rotavirus end up hospitalized

• Positive-sense single stranded RNA [(+) ssRNA]
• Baltimore Classification System= IV
• Isolated froms birds, cats, dogs, pigs, sheep, cows, and humans
• Symptoms include diarrhea, headache, malaise, and nausea; vomiting may occur but is not frequent
• Due to characteristics this virus is related to the Norwalk-Flu virus (Caliciviruses).

• Is an inflammation of the liver that can be caused by a number of hepatitis viruses, namely A to E
• Hepatitis A and E are transmitted by the fecal-oral route and neither one result in chronic infection
• Both infections result in gastroenteritis and can be transmitted through contaminated food and water

• Caused by the hepatitis A virus (HAV)
• Infections can be isolated or widespread
• Good personal hygeiene and appropriate sanitation will curb the spread of the disease
• Vaccines are available for long-term prevention among people 12 months of age and older

• Rare in the United States
• Caused by the hepatitis E virus (HEV)

Most (Mycoses) fungai infections that effect the GI tract are opportunistic and;

DO NOT effect those who are otherwise healthy. Unless the individual is immunosuppressed.

Mycoses are not much of a problem at all.

• Caused by a variety of opportunistic organisms of the genus Candida
• Candida albicans is part of the normal gastrointestinal flora of about 80% of the human population, and DOES NOT usually cause any problems
• Oral candidiasis "thrush" is rare in healthy iindividuals; 5% of newborns; 10% of elderly; but is common in immunocompromised patients
• Rarely ever diplays any virulence
• Several antifungal preparations are available for the treatment of Candidiasis

• Caused by organisms in the genus Aspergillus
• Found in soil, food, compost, agricutlural buildings and air vents of homes and offices
• Aspergillus flavus is a mold common on corn and peanuts, and is one of several species of mold know to produce aflatoxin, a carcinogenic substance
• Toxic effects include acute hepatitis, immunosuppression, and hepatocellular carcinoma
• FDA monitors and regulated the allowable aflatoxin concentration in food and feed

• Clavicep purpurea is a fungus that contaminated rye and wheat and produces a substance called alkaloids.
• Alkaloids effect the centeral nervous system
• Ergotism is a result of ingestion of alkaloids (ergomines) produced by the fungus
• Symptoms are: hallucinations, severe GI upset, gangrene, and a painful burning in the extremities (St. Anthony's Fire)

Although all infectious agents of humans are parasites, parasitic diseases are often defined as those caused by protozoans or helminths.

Protozoans are unicellular eukarotyes found in a wide range of habitats; most free living and not harmful to humans. 

Some are parasites and capable of causing debilitating and deadly diseases. 

They enter the human body either as a trphozoite, the active feeding and reproductive stage, or as a cyst, the dormant stage, becoming active under the appropriate environmental conditions.

• Present in the digestive tracts of about 10%nof the human population
• Carriers are found predominantly in underdeveloped countries, especially in rural areas where wate and sanitation practices are deficient
• Infections most commonly occur through ingestion of water cantaminated with human feces that contain cysts
• No animal reservoir
• Another way of transmission is by fecal contamination of hands or food or during any other activites that will allow the organism to spread from the fecal material of one person to the GI tract of another

• Caused by protozoan Cryptospordium, parasitic diarrheal disease
• Spread via fecal-oral route, contaminated water and via uncooked or cross-contaminated food
• Resistant to chlorine and chlorine-based disinfectants
• Most common waterborne disease
• Symptoms: watery diarrhea, dehydration, weight loss, stomach cramps or pain, fever, nausea, and vomiting

• Human tapeworm infection
• Aquired by consuming raw or undercooked meat of infected animals
• Taenia saginata is common in beef and Taenia solium is common in pigs
• Tapeworm infestation can be treated and eradication of the tapeworm is expected after treatment
• DOES NOT present with any symptoms

• Enterobius vermicularis
• Pinworm
• AKA: seat-worm
• Found mainly in pre-school age children and young children
• Resides in the area of the rectum causing profound itchiness in the region
• Enters the GI tract via contaminated fingers

• Caused by Ascaris lumbricoides
• Most common nematode infection of humans
• most common in tropical and subtropical areas
• Endemic in rural areas of the southeastern United States
• Infection occurs after accidental ingestion of Ascaris eggs
• Asymptomatic but the illness may cause slower weight gain and growth
• Surgery may be needed to repair intestinal damage and to remove worms with heavy infestation
• Drugs commonly used against Ascaris: mebendazole, albendazole, and pyrantel pamoate