Campylobacter is the most common source of bacterial infections in the developed world.
Correct Answer: Campylobacter
Helicobacter pylori infection causes what may be the most prevalent disease in the world, gastric ulcers. The organism is found in 30–50% of all adults in developed countries and in practically 100% of adults in developing countries.
Correct Answer: Helicobacter pylori
90% of nosocomial (hospital acquired) infections are caused by Clostridium difficile. E. coli is also a cause but usually only seen in infants. Nosocomial C. difficile is usually seen when the normal flora have been reduced by antibiotic therapy and can be very serious. Spread can be prevented by washing hands and changing gloves between patients.
Correct Answer: Clostridium difficile
Dental plaque is considered a biofilm because it is permeated with channels that transport nutrients to the bacteria making up the plaque and remove the waste products of bacterial metabolism.
Correct Answer: A biofilm
Streptocuccus mutans is the main cause of dental caries and initiates the problem.
Correct Answer: Streptococcus mutans
These are all features of Enterobacteriaceae.
Correct Answer: All the choices
E. coli can produce every toxin seen in the Enterobacteriaceae family, including a pore-forming toxin, Shiga toxin, heat-stable toxin, and heat-labile toxin.
Correct Answer: All of the choices
Traveler’s diarrhea is caused by enterotoxigenic E. coli which is transmitted by consumption of food or water that is contaminated either by actively infected individuals or by carriers of the organism. Uncooked foods are the greatest risk. Person-to-person transmission is very rare.
Correct Answer: Contaminated food or water
Bacillary dysentery is caused by Shigella dysenteriae.
Correct Answer: Shigella
Salmonella enterica is divided into serotypes based on the different lipopolysaccharide O antigens found in the cell wall. H and K antigens are used for further subdivision.
Correct Answer: O antigens
Typhoid fever also causes high fever and diarrhea but perforation of the colon wall is the most serious and can be lethal.
Correct Answer: Perforation of the colon wall
Cholera is characterized by a short incubation time, about two days.
Correct Answer: Long incubation period
Viral gastrointestinal infections are characterized by short incubation periods and fecal-oral transmission. Like bacterial infections, viral infections of the digestive system produce diarrhea, but viral infections usually also induce vomiting. They do not cause enteric fever.
Correct Answer: Vomiting and diarrhea
Hepatitis B is found worldwide, though its prevalence varies from one country to another. Chronic carriers are the main reservoir for the virus. In the United States, it is estimated that 1.5 million people are infected with hepatitis B, and there are 300,000 new cases each year.
Correct Answer: Hepatitis B
Giardia is one of the most widely distributed intestinal protozoans and is found in fish, amphibians, reptiles, birds, and mammals.
One of the symptoms of late stage cholera is the appearance of the rice stool in which the stool contains flecks of mucus that look like grains of rice.
Correct Answer: Cholera
Most of the normal flora is found in the large intestine (the mouth is also an important location).
Correct Answer: Large intestine
Salmonella is commonly found in poultry and poultry products including eggs.
Correct Answer: Salmonella
Most infections of the digestive system result in the loss of fluids and electrolytes through diarrhea and dysentery. Therefore the most important remedy is replacement of these lost fluids.
Correct Answer: Water and electrolytes
Antibiotic therapy of Salmonella infections is not appropriate because it increases the duration and frequency of the carrier state.
Correct Answer: False
Hepatitis D is a small single-stranded RNA virus that is currently referred to as a satellite virus because it requires the presence of hepatitis B antigens to complete its replication cycle and become infective.
As the worms move around the intestine, they leave behind bleeding points at former sites of attachment. As the worms can live for up to 14 years, there can be many of these bleeding points, and this can lead to significant blood loss.
Correct Answer: True