Gram Negative Foodborne Pathogens Vocabulary

Vocabulary flashcards covering major Gram-negative foodborne bacterial pathogens, their taxonomy, key features, virulence factors, and associated diseases based on lecture notes.

Microaerophile

An organism, such as Campylobacter jejuni, that requires reduced levels of oxygen ($3\text{--}5\,\%$) and elevated carbon dioxide ($5\text{--}10\,\%$) for optimal growth.

Campylobacter jejuni

A Gram-negative, curved rod-shaped microaerophilic mesophile with an optimal growth temperature of $41\text{--}43\,^{\circ}\text{C}$, characteristically exhibiting darting, corkscrew-like motility.

Modified charcoal cefoperazone deoxycholate agar (mCCDA)

A selective culture medium used for the isolation and identification of Campylobacter species from food and clinical samples.

Guillain-Barré syndrome

An acute autoimmune neuromuscular disease causing motor and sensory deficits that start in lower extremities, recognized as a post-infectious complication of Campylobacter infection occurring in $1\text{--}2$ per $100,000$ people.

Vibrio

A genus of halophilic, facultatively anaerobic Gram-negative bacteria that naturally persist in estuarine and marine environments, named for their ability 'to vibrate with tremulous motion'.

Cholera gravis

A severe form of Vibrio cholerae infection characterized by rapid, profuse watery diarrhea at rates of $500\text{--}1000\,\text{mL/h}$ ($10^{11}\text{--}10^{13}\,\text{CFU/g}$), which can lead to fatal dehydration within hours.

Rice-water stool

The characteristic clear, watery stool containing flecks of mucus produced during severe Vibrio cholerae infection.

Thermostable direct hemolysin (TDH)

A major virulence toxin produced by Vibrio parahaemolyticus that exhibits hemolytic, cytotoxic, cardiotoxic, and enterotoxic activities by forming pores in host cell membranes.

Cronobacter sakazakii

An opportunistic, desiccation-resistant Gram-negative bacterial pathogen associated with powdered infant formula that can cause severe, high-mortality infections in neonates.

Necrotizing Enterocolitis

The most common inflammatory intestinal disorder observed in neonates, recognized as a primary clinical syndrome resulting from Cronobacter infection.

Yersinia enterocolitica

A Gram-negative psychrotrophic bacterium capable of growth at temperatures ranging from $-2\,^{\circ}\text{C}$ to $42\,^{\circ}\text{C}$, primarily transmitted through undercooked pork products.

Pseudoappendicular syndrome

A clinical presentation of Yersinia enterocolitica infection, most commonly seen in children under $5$ years old, that clinically mimics acute appendicitis.

Invasin

An outer membrane protein of Yersinia enterocolitica that interacts with host cell surface receptors to facilitate bacterial attachment and cell entry.

Pathotype

A group of bacterial strains within a species that are categorized together based on shared virulence attributes, such as specific adhesins, secretion systems, and toxin production.

EPEC (Enteropathogenic E. coli)

An E. coli pathotype that causes watery diarrhea without producing enterotoxins, characteristically inducing attaching-and-effacing (A/E) lesions on intestinal cells.

ETEC (Enterotoxigenic E. coli)

A major cause of infantile and traveler's watery diarrhea in developing regions that colonizes using fimbrial factors and secretes heat-stable (ST) and heat-labile (LT) enterotoxins.

EIEC (Enteroinvasive E. coli)

An E. coli pathotype that invades and multiplies inside colonic epithelial cells, producing non-bloody or dysentery-like diarrhea without enterprise toxin secretion.

EAEC (Enteroaggregative E. coli)

An E. coli pathotype associated with persistent diarrhea, defined by a 'stacked-brick' pattern of adherence to epithelial cells and the production of EAST1 enterotoxin and hemolysin.

STEC (Shiga Toxin-producing E. coli)

An E. coli pathotype (including serotype O157:H7) that colonizes the large intestine and secretes Shiga toxins, causing bloody diarrhea, hemorrhagic colitis, and Hemolytic Uremic Syndrome.

Hemolytic Uremic Syndrome (HUS)

A severe, life-threatening clinical outcome of STEC infection defined by acute renal failure, hemolytic anemia, and thrombocytopenia.

Thrombotic thrombocytopenic purpura (TTP)

A rare but highly fatal complication of Shiga toxin exposure causing microthrombi formation in kidney and brain capillaries with severe neurological manifestations.

Globotriaosylceramides (Gb3s)

Glycolipid surface receptors on mucosal Paneth cells and kidney endothelial cells that specifically bind Shiga toxin, triggering endocytosis into host cytoplasm.

Shigellosis

An acute, highly contagious intestinal infection (bacillary dysentery) caused by Shigella species, marked by a low infectious dose ($10\text{--}500\,\text{CFU}$) and tissue invasion via intestinal M cells.

Salmonella enterica

A species of Gram-negative, facultatively anaerobic rod-shaped bacteria comprising $6$ subspecies and $2,579$ serovars, responsible for the vast majority of human salmonellosis cases.

Typhoid Fever

A severe systemic infection caused by Salmonella enterica serovars Typhi or Paratyphi, characterized by an incubation period of $7\text{--}28\,\text{days}$, high fever, prostration, and dissemination to the reticuloendothelial system.

Salmonella Pathogenicity Island 1 (SPI-1) T3SS1

A Type III Secretion System encoded by Salmonella that injects effector proteins (such as SipA, SipC, SopB, SopE, and SopE2) to mediate invasion into non-phagocytic intestinal epithelial cells.