Lecture 17: Upper Alimentary Tract Infections

(Upper Alimentary Tract Infections) Lecture 17 Upper Alimentary Tract: · aka upper digestive tract · includes: mouth, salivary glands, esophagus, stomach Normal Flora of the Mouth · age and dentation dependent ↳ dentation refers to the teeth, if they are present, gone, or in the process of being lost · More organisms in saliva than in feces · dominating flora are streptococcus species (mostly alpha) Infections of the Oral Cavity · mouth has a different set of microorganisms due to presence of teeth · most organisms make specific attachments to the teeth (pellicle) or mucosal surfaces · 1-1.5 liters of saliva per day from salivary glands ↳ flushes mouth ↳ secretes IgA, lysozyme, lactoperoxidase, lactoferrin, WBC, amylase ↳ if saliva decreases (like between meals)there is 4x the increase in microbial populations · Dehydrated patients often have month overgrown with microorganisms, resulting in bad breath Bad Breath · the anterior of the tongue often gets the flora rubbed off, so the posterior often has more flora and smells worse · bad breath is often caused by the waste products of anaerobic oral bacteria · most of the compounds that cause bad breath (hydrogen sulfide, cadaverine etc.) are waste products of bacterial metabolism · risks of piercing tongue/mouth: ↳ HIV, Hepatitus ↳ most commonly soft tissue infections Soft tissue infections include: ear piercings and infections from tongue piercings Candida Albicans · opportunistic fungus, yeast-like in culture outside of body · pseudohyphae in tissues (ie. tongue) · Common cause of mouth and throat infection in neonates and immunosuppressed individuals ↳ inhalation steroids ↳ chemotherapy ↳ broad spectrum antibiotics ↳ Immune defects and cancer · Thrush: growth of mycelium of pseudohyphae on tongue, may spread to esophagus (painful and hard to swallow) Structure of a Tooth · non-shedding surface (enamel) allows accumulation of Gingivitis · mild inflammation of gums ↳ usually due to bacterial infection · gums may bleed when brushed · reversible · prevention: ↳ brush teeth twice a day ↳ use soft tooth brush ↳ reduce sugar intake ↳ flossing ↳ antiseptic mouth wash ↳ regular dental checkups many bacteria Periodontal Disease (Periodontitus) · more severe · inflammation and degeneration of supporting teeth structures Gum has receded. Good area ↳ can lead to tooth loss for biofilm and infection. Can · may occur even without caries wear away bone Dental Plaque · a biofilm · plaque usually starts out when encapsulated streptococci congregate and form a community of bacteria and polysaccharide matrix · as plaque matures anaerobes start entering · as layer gets thicker it can be depleted of oxygen ↳ anaerobes like to grow · the more plaque you have, the worse your breath Bacterial Diversity in Oral Cavity · over 500 species of bacteria · ~415 found in subgigival plaque · most can physically interact with and adhere to other species (coaggregation) · Early colonizers vs. Late colonizers ↳ early are the streptococci ↳ late are anaerobic G- bacteria Proteins in pellicle that can bind to bacteria Dental Caries · accumulations of microorganisms and their by-products form plaque (BIOFILM) · carbohydrates converted locally under the plaque into lactic acid, which attacks tooth enamel · most important cariogenic bacterium is Streptococcus mutans · local "immune" defenses against caries: ↳ saliva: contains lysozyme and lactoperoxidase (antibacterial enzymes) ↳ crevicular fluid in gingival crevice: contains complement, antibodies and neutrophils · prevention: good oral hygiene (tooth brushing, flossing, plaque removal, mouthwashes, fluoride treatment) Tooth Decay · if caries develops, the bacteria may penetrate the inside of the tooth (through dentine even to pulp) · When bacteria penetrate to pulp, contact is made with nerves and blood vessels which can lead to ABCESS ↳ Abscess: root of teeth press on nerves and causes extreme pain or kill nerve needing a root canal · if abscess not treated, soft tissue involvement with larger abscesses are formed · Abscess formation: ↳ polymicrobial, predominantly anaerobic flora ↳ contains pus and necrotic tissue debris ↳ localized well defined swelling, often pointy ↳ can progress to cellulitis Actinomycosis ("lumpy jaw") · actinomyces israelli: G+ filamentous anaerobic rod ↳ part of normal flora · abscess formation, healing and scarring leads to deformation of tissue, hence "lumpy jaw" · tendency to chronic infection · triggered by dental procedures/wounds . S pyogenes Vincent's Disease ("Trench Mouth") · common in WWI trench soldiers · also called acute necrotizing ulcerative gingivitis (ANUG) or Vincent's Angina · caused by anaerobic G- rods together with spirochaetes · Severe ulcerative disease with pain, breath extremely foul · treated with antibiotics active against anaerobes, and surgical removal of necrotic tissue Main Causes of Oral Infections: · HSV-1 herpes simplex (cold sores) · EBV (lesions and oral hairy leukoplakia) · Cocksackie virus (hand foot and mouth) Mumps · infection of the parotid gland (salivary gland) · RNA enveloped virus · Droplet transmission · Most infectious 48 hours before symptoms begin · Virus multiplies in lymph glands in throat, then move through the blood to the parotid glands · Symptoms: inflammation and swelling of parotid glands, fever, pain when swallowing · Complications: encephalitis, pancreatitis, orchitis (inflammation of testis), oophoritis (inflammation of ovaries) · Sterility can be an end result when teenagers and adults get mumps Heliobacter pylori · causes gastric and duodenal ulcers (peptic ulcer disease) · wavy G- microaerophilic bacillus · 30-50% of world has antibodies (exposed to it) · associated with contaminated drinking water · Specialized bacterium: survives in acid conditions in stomach · stomach lined with a layer of mucous protecting stomach lining from the acidity · increased secretion of gastrin (induces more HC1) · virulence factors: ↳ produces large amounts of urease, urea is broken down to ammonia and the PH locally around the bacterium increases (protection against stomach acidity) ↳ Special flagella that allows them to move in the thick mucous layer · Complication: gastric cancer (H. pylori is on the list of oncogens at WHO) · Diagnosis: ↳ stool antigen detection ↳ urea breath test (measures C14 in breath) ↳ Serology, culture of biopsy specimens (invasive methods) Kills cells locally · Treatment: Cancer causing ↳ acid antagonist (inhibitor to reduce acidity) and at least 2 different antibiotics so they don't develop resistance Virulence factor diagram eg. erythromycin and metronidazole