Microbial Diseases Flashcards

Flashcards covering microbial diseases of the nervous and digestive systems.

CNS

Central Nervous System; controls most functions of the body and mind; consists of the brain and spinal cord.

PNS

Peripheral Nervous System; consists of nerves from the skin, muscle, and organs to the spinal cord and brain; connects the CNS to the limbs and organs.

Meningitis

Inflammation of the meninges.

Encephalitis

Inflammation of the brain itself.

Meninges

Three layers of protective tissue: dura mater, arachnoid mater, and pia mater.

Bacterial Meningitis Symptoms

Fever, headache, and a stiff neck; may progress to convulsions and coma.

Bacterial Meningitis Causes

Streptococcus pneumoniae, Neisseria meningitidis, Haemophilus influenzae; cause shock and inflammation due to endotoxins.

Haemophilus influenzae

Aerobic, encapsulated, gram(-) coccobacillus; penetrates the epithelium of the nasopharynx and invades the blood capillaries directly.

Neisseria meningitidis

Aerobic, encapsulated, gram-negative cocci; inhabits the human nasopharynx.

Meningococcal Meningitis Transmission

Spreads from person-to-person by coughing, kissing, sharing drinks, or living together.

Meningococcal Meningitis Characterization

Characterized by a rash that does not fade when pressed.

Meningococcal Meningitis Neurologic Signs

Convulsions or coma.

Meningococcal Meningitis Signs of Meningeal Irritation

Spinal rigidity, hamstring spasms, and exaggerated reflexes.

Meningococcal Meningitis Skin Lesions

Petechiae or purpura from the first to the third day of illness; lesions may be more prominent in areas of the skin subjected to pressure.

Meningococcal Meningitis Treatment

Penicillin or cephalosporin.

Streptococcus pneumoniae

Encapsulated, gram-positive diplococci; invades the bloodstream, crosses the blood-brain barrier, and multiplies within the fluid surrounding the spine and brain.

Meningitis Diagnosis

Spinal tap (lumbar puncture) for CSF; Gram stain; Culture.

Meningitis Treatment

Chemotherapy using 3rd-generation cephalosporins.

Listeria monocytogenes

Gram-positive bacilli; causes stillbirth and neurological disease in animals and humans; acquired by eating contaminated food.

Listeriosis Affected Individuals

Primarily affects pregnant women, newborns, older adults, and people with weakened immune systems.

Listeriosis Transmission

Eating contaminated ready-to-eat deli meats, hot dogs, refrigerated pâtés, meat spreads, unpasteurized milk, soft cheese, refrigerated smoked seafood, or raw sprouts.

Clostridium tetani

Obligately anaerobic, endospore, gram-positive rod; found in soil contaminated with animal feces.

Tetanospasmin

Neurotoxin released upon death and lysis of Clostridium tetani; blocks the relaxation pathway, causing muscle spasms.

Lockjaw

Jaw muscle spasm preventing the mouth from opening; symptom of tetanus.

Opisthotonos

Back muscle spasm causing head and heels to arch; symptom of tetanus.

Tetanus Acquisition

Through puncture wounds from rusty nails or any sharp objects.

Tetanus Prevention

DTP and tetanus toxoid vaccines.

Tetanus Treatment

Debridement (removal of damaged tissues).

Clostridium botulinum

Obligately anaerobic, endospore-forming; found in soil and freshwater sediments; causes food poisoning.

Botulinum Toxin

Neurotoxin that blocks the release of acetylcholine, causing progressive flaccid paralysis.

Infant Botulism

Ingestion of contaminated soil and other materials; occurs in infants 5-20 weeks of age.

Wound Botulism

Occurs when Clostridium botulinum grows in deep wounds.

Botulinal Toxin - Beneficial Aspects

Used in Botox to eliminate worry lines, treat excessive muscle contractions, and prevent armpit sweating.

Mycobacterium leprae

Acid-fast bacilli; grows best at 30°C; damages peripheral nerves and can affect the skin, eyes, nose, and muscles; causes leprosy.

Tuberculoid (Neural) Leprosy

Characterized by regions of the skin that have lost sensation and are surrounded by a border of nodules.

Lepromatous (Progressive) Leprosy

Skin cells are infected, and disfiguring nodules form all over the body; can cause a lion-faced appearance and deformation of the hand.

Leprosy Transmission

When a person with Hansen's disease coughs or sneezes, and a healthy person breathes in the droplets containing the bacteria; prolonged, close contact is needed.

Poliomyelitis Cause

Poliovirus; ingestion of water contaminated with feces containing the virus.

Poliomyelitis Mechanism

Multiplies within the cytoplasm of motor neurons, causing paralysis.

Salk Vaccine

Viruses inactivated by formalin; Inactivated poliovirus vaccine (IPV).

Sabin Vaccine

Contains three living, attenuated strains of the virus; Oral poliovirus vaccine (OPV).

Rabies Cause

Rabies virus; transmitted through bites of an infected animal.

Rabies Symptoms

CNS involvement, spasms of the muscles of the mouth and pharynx, hydrophobia.

Furious Rabies

Characterized by being highly excitable.

Paralytic Rabies

Characterized by minimal excitability; paralysis is usually transient but fatal.

Arboviral Encephalitis

Caused by mosquito-borne viruses (arthropod-borne viruses).

Arboviral Encephalitis Symptoms

Chills, headache, and fever; mental confusion and coma.

Cryptococcus neoformans

Spherical cells resembling yeasts; produce polysaccharide capsules; cause meningitis.

Cryptococcosis

Initially causes infection of the lungs and spreads through the bloodstream; found in bird feces.

Cryptococcosis Treatment

Amphotericin B, oral azole agent (preferably fluconazole), or ketoconazole.

Prion

An infectious protein particle similar to a virus but lacking nucleic acid; can trigger normal proteins in the brain to fold abnormally.

Transmissible Spongiform Encephalopathies (TSEs)

Spongiform degeneration of the brain characterized by vacuolation in nervous tissue accompanied by neuronal death and gliosis.

TSE Symptoms

Personality changes, psychiatric problems, lack of coordination, unsteady gait, involuntary jerking movements, unusual sensations, insomnia, confusion, or memory problems.

Sheep Scrapie

Affects the nervous systems of sheep and goats; causes behavioral changes, tremor, pruritus, and locomotor incoordination.

Creutzfeldt-Jakob Disease

A rare, degenerative, fatal brain disorder; destroys brain cells, and causes tiny holes in the brain; leads to ataxia and dementia.

Bovine Spongiform Encephalopathy (Mad Cow Disease)

A fatal disease that slowly destroys the brain and spinal cord in cattle; brain develops tiny holes, and the animal loses control over its movements.

Digestive System Function

Digestion and absorption.

Digestive System Major Parts

Salivary glands, pharynx, esophagus, stomach, small intestine, large intestine, rectum, liver, gallbladder, pancreas.

Fecal-Oral Route

Transmission of microbial diseases of the digestive system; broken by proper sewage disposal, disinfection of drinking water, and proper food preparation and storage.

Normal Microbiota of the Digestive System

300 species in the mouth; large numbers in the large intestine, including Bacteroides, Escherichia coli, Enterobacter, Klebsiella, Lactobacillus, and Proteus.

Dental Caries

Tooth decay.

Periodontal Disease

Infections and inflammation of the gums and supporting structures of the teeth; Includes gingivitis and periodontitis.

Streptococcus mutans

Gram + cocci in chain; Viridans species; Major cause of tooth decay; has slime layer for attachment.

Tartar

The hard calcified deposits that form and coat the teeth and gums; formed when plaque is left untreated.

Gingivitis

Red and puffy gums that bleed easily when brushed.

Periodontitis

Inflammation of the gums and supporting structures of the teeth.

Acute Necrotizing Ulcerative Gingivitis

Vincent disease/Trench mouth; caused by anaerobic bacteria like Prevotella intermedia; causes pain during chewing.

Acute Necrotizing Ulcerative Gingivitis Treatment

Metronidazole, oxidizing agents, and debridement.

Staphylococcal Food Poisoning cause

Staphylococcus aureus; inhabitant of the nasal passages and skin infections; produces heat-stable enterotoxin.

Enterotoxin Features

Heat-stable up to 30 minutes boiling; resistant to drying, radiation, and high osmotic pressure.

Shigellosis

Bacillary dysentery; caused by Shigella species; produces Shiga toxin causing inflammation and bleeding.

Shigella Transmission

People with shigellosis shed the bacteria in their feces; spreads through contaminated water or food.

Salmonellosis

Salmonella Gastroenteritis; common species is Salmonella enterica; produces endotoxin.

Salmonellosis Symptoms

Nausea, diarrhea, fever, abdominal cramps, and vomiting;usually begin 6-48 hours post-ingestion

Typhoid Fever

Infectious bacterial fever caused by Salmonella enterica Typhi; causes ulceration and perforation of the intestinal wall.

Salmonella enterica Typhi Antigens

H (flagellar), O (cell wall), and Vi(capsular).

Typhoid Fever Lab Tests

Antibody IgM detection, Widal test, Tubex TF, Blood Culture, Real Time PCR

Cholera

An acute, diarrheal illness caused by infection of the intestine from Vibrio cholerae; causes rice-watery stool.

Vibrio cholerae

Gram-negative, comma-shaped bacteria; produces heat-labile exotoxin (choleragen).

Cholera Symptoms

Watery diarrhea, vomiting, leg cramps; rapid loss of body fluids leads to dehydration and shock.

Non cholera Vibrios

Vibrio parahaemolyticus, Vibrio mimicus, Vibrio alginolyticus, Vibrio hollisae, Vibrio vulnificus

Escherichia coli Gastroenteritis

Inflammation of the lining of the intestines; Normal flora of digestive tract.; Occurs as traveler's diarrhea and epidemic diarrhea in nurseries

Enterotoxigenic Escherichia coli (ETEC)

Produces adhesins to bind to intestinal mucosa and enterotoxins (ST and LT) responsible for diarrhea; common cause for traveler's diarrhea.

Enteroinvasive Escherichia coli (EIEC)

Produces an infection similar to Shigella.

Enterohemorrhagic Escherichia coli (EHEC)

Causes watery diarrhea; can lead to Hemolytic-uremic syndrome (HUS); E. coli strain O157:H7.

Enteropathogenic Escherichia coli (EPEC)

Enteroadherent E.coli; Commonly affect children in nurseries and day care centers

Campylobacter Gastroenteritis cause

Campylobacter jejuni; most common bacterial cause of gastroenteritis in the world; usually transmitted in cow's milk and undercooked poultry.

Campylobacter Gastroenteritis symptoms

Diarrhea (may be bloody), cramps, fever, and vomiting.

Helicobacter pylori

Gram-negative, curved-shaped bacterium; causes stomach cancer and peptic ulcer disease (PUD).

Helicobacter pylori Transmission

Believed to be mainly fecal-oral or possibly oral-oral.

Helicobacter pylori Symptoms

Burning epigastric pain, nausea, vomiting, and loss of appetite

Helicobacter pylori Treatment

bismuth quadruple therapy and Clarithromycin triple therapy

Yersinia Gastroenteritis

Caused by Y. enterocolitica and Y. pseudotuberculosis; causes enterocolitis, acute diarrhea, terminal ileitis, mesenteric lymphadenitis, and pseudoappendicitis

Yersinia Gastroenteritis Symptoms

Fever, abdominal pain, diarrhea, which is often bloody, and right-sided abdominal pain

Clostridium perfringens Gastroenteritis

Spore-forming gram-positive rods bacterium; grows in intestinal tract producing exotoxin; commonly found on raw meat and poultry.

Clostridium perfringens Gastroenteritis Symptoms

Develop diarrhea and stomach cramps within 6 to 24 hours after eating contaminated food.

Bacillus cereus Gastroenteritis

Gram positive bacilli, spore forming; ingestion of bacterial exotoxin, produces emetic or diarrheal symptoms.

Human Enteroviruses Transmission

transmitted from person to person via direct contact with virus shed from the gastrointestinal or upper respiratory tract.

Hepatitis A

A single-stranded RNA virus; Transmission: Fecal-oral; low mortality, no chronic state and no risk for cancer; Treatment: Supportive

Hepatitis

Inflammation of the liver; May result from drug or chemical toxicity, EB(Epstein-Barr ) virus, CMV, or the Hepatitis viruses