Enteric Infections (Bacterial and Viral)

rotavirus

(ds RNA) virus that causes gastroenteritis

PCR

(polymerase chain reaction) a method used to rapidly make multiple copies of a specific segment of DNA; can be used to make millions of copies of DNA from a very small amount of DNA

Caliciviruses

A group of naked (+) ssRNA viruses major cause of gastroenteritis (norovirus)

endospore

A thick-walled protective spore that forms inside a bacterial cell and resists harsh conditions - Clostridium perfringens is a spore-former

raw agricultural commodities (RAC)

Agricultural products that are assumed to be contaminated with Listeria

Salmonella

Bacteria that causes food poisoning by producing toxins Symptoms: fever, stomach cramps, vomiting and diarrhea Caused by eating food contaminated with salmonella e.g. uncooked chicken

16S RNA

DNA encodes of the small ribosomal subunit which is present in all bacteria and is highly conserved in sequence and size. This is used to identify and categorize bacterial pathogens

EHEC

Enterohemorrhagic E. coli. A type of E. coli such as O157:H7 that causes bloody diarrhea due to shiga-like toxin.

O-polysaccharide

Extends outward from the core polysaccharide in gram negative. Functions as an antigen and is useful for distinguishing species of gram-negative bacteria.

Shiga toxin

Found in Shigella, and E. coli O157:H7 Cleaves host cell rRNA (inactivates 60S ribosome) Enhances cytokine release, causing HUS

Clostridium perfringens

Gram-positive, endospore-forming, obligately anaerobic rod, associated with foods containing animal intestinal contents Produces an exotoxin and Symptoms are usually mild super-fast reproduction - incubation = 8 to 12 hours after ingestion

HPAI

Highly pathogenic avian influenza (H5N1) - causes death in birds (nearly 100%), spread to cattle and may be transmitted via unpasteurized milk

adenovirus

Linear dsDNA; naked; replicates in the nucleus - causes common cold (and can cause GI symptoms)

hepatitis E

Similar to hepatitis A, but rarely occurs in the US - may be found in pigs

Listeria monocytogenes

Small gram-positive, non-spore-forming rod - facultative intracellular parasite that grows in the cold and is associated with unpasteurized milk products (and ready to eat meats)

parvoviruses

Small, naked, linear ssDNA viruses. Their genetic information is so limited that they must enlist the aid of an unrelated helper virus or a dividing host cell to replicate

infection

The invasion of body tissues by disease-causing pathogens that reproduce in or on the host

Escherichia coli 0157:H7

Toxin-producing strain of E. coli & Leading cause of diarrhea worldwide - has a shiga-toxin that causes HUS (hemolytic uremic syndrome) and dysentery

Staphylococcus aureus

a form of staphylococci that commonly infects wounds and causes serious problems such as toxic shock syndrome or produces food poisoning

norovirus

calicivirus that causes half of all viral foodborne illness and causes 'stomach flu' or gastroenteritis

whole genome sequencing (WGS)

complete DNA sequence of an organism's genome at a single time; generating accurate reference genomes for microbial identification, and other comparative genomic studies

intoxication

disease caused by exposure (consumption) of a pre-formed toxin (e.g. Staph aureus)

ELISA

enzyme-linked immunosorbent assay (used to detect either antigen from pathogen or antibodies from host)

Flagellar H antigen

found in the flagellum; used for Salmonella and E. coli serotyping (some antigenic shifting)

hepatitis A

inflammation of the liver caused by the hepatitis A virus (HAV), usually transmitted orally through fecal contamination of food or water

gastroenteritis

inflammation of the mucous membrane lining the stomach and intestines

toxico-infection

pathogen enters the GI tract, multiplies and produces a toxin in GI tract, causing illness

reservoir

the natural habitat of a pathogen; sum of the potential sources of an infectious agent

serotyping

the subdivision of a species or subspecies into an immunologic type, based upon antigenic characteristics (which antibodies recognize their structures)

serovar

variation within a species that leads to them making different antibodies

germination (endospore)

vegetative cell emerges from free spore (becomes metabolically active)

picornaviruses

very small, naked, polyhedral, (+) sense RNA viruses. They include the Enterovirus, Hepatovirus, and Rhinovirus

enteric virus

viruses that are generally transmitted via fecal-oral route and often cause gastroenteritis