GI & Skin
Gastrointestinal Tract
Chapter 28
Microbiology for Surgical Technologists
The Digestive Tract
Basic Anatomy
The digestive tract is a long tube that begins at the mouth and ends at the anus
Digestion is helped with accessory organs that include the teeth, salivary glands, liver, gallbladder, and pancreas
It begins in the mouth where the food is ground by the teeth and mixed with saliva
Saliva contains two enzymes
Amylase – breaks down carbohydrates into simple sugars
Lysozyme – destroys bacteria, protecting mucous membranes from infection and teeth from decay
The food is then swallowed and passes through the esophagus into the stomach
The stomach secretes pepsinogen and hydrochloric acid which combine to produce pepsin
Pepsin is the enzyme that breaks down protein
The stomach churns and contracts to help the enzymes break the food down into smaller particles
The food then passes into the small intestines which are divided into three sections
Duodenum
Jejunum
Ileum
The pancreas secretes the enzymes lipase, carbohydrase and protease which break down fats, carbohydrates and proteins
It also secretes the hormones glucagon and insulin that regulate and control blood sugar levels
The liver produces bile salts that break down fats
The gallbladder contains bile produced by the liver, it stores and concentrates it until it is needed
About 80% of nutrient absorption occurs in the small intestine
The food is then moved into the large intestine through the ileocecal valve
The large intestine (colon) is divided into three sections
The ascending colon, transverse colon, and descending colon
The main function of the colon is to absorb water
The food then passes into the sigmoid colon and rectum and is expelled from the anus
The Colon
Resident Flora
The GI tract contains a lot of resident flora
The mouth contain large amounts of bacteria, whereas the stomach and upper small intestine do not
Why?
The lower small intestine and the colon contain most of the resident flora
The colon contains approx 100 billion bacteria per gram of feces
Alcohol and simple sugars can alter the environment of the colon
Alcohol can kill resident flora and sugar can feed unfavorable bacteria disrupting the ratio of friendly and unfriendly bacteria
Antibiotics kill the pathogenic bacteria that they were designed for but can also destroy the favorable flora
Pathogens and Diseases
Of the GI Tract
Dental Caries
Teeth come into contact with large amounts of bacteria causing dental plaque and decay
Oral bacteria convert sugars into lactic acid which eats away at tooth enamel
The bacterium that causes the most damage is Streptococcus mutans
Dental Caries
Dental Caries
Dental Caries
Gingivitis/Periodontitis
Gingivitis is an infection of the gums, characterized by bleeding an sore gums
If left untreated it can progress into a chronic condition called periodontitis
Pus pockets form around the teeth destroying bone and tissue that anchor the teeth
Caused primarily by the Porphyromonas species
Acute necrotizing ulcerative gingivitis (trench mouth) is a serious infection causing bleeding, pain and difficulty with chewing
Caused by Prevotella intermedia
Periodontitis
Neglected Teeth Before Cleaning
Neglected Teeth After Cleaning
Shigellosis
Also known as
Shigellosis
Caused by the exotoxin of Shigella dysenteriae
Typically acquired through the fecal-oral route
Symptoms include:
Bloody diarrhea with mucous and pus, nausea and vomiting, fever, and convulsions
Treatment
Fluid and electrolyte replacement
Antibiotic therapy
The 4 F’s of Food Poisoning
Food
Fingers
Flies
Feces
Previously Discussed Diseases
Escherichia coli
Traveler’s diarrhea
Staphylococcus enterotoxicosis
Caused by S. aureus
Food handlers can rub their nose and infect food
Clostridium botulinum
Causes botulism
Salmonella
Parasites of the GI Tract
The intestinal tract is home to many species of protozoa and worms
Most of those that cause disease are acquired through the fecal-oral route
Some worm larvae can penetrate the skin and make their way to the GI tract
Infected animals can be eaten and infect people
Protozoan pathogens include Entamoeba histolytica, Giardia lamblia, and Cryptosporidium
Symptoms can be acute or chronic, with mild to severe diarrhea and inflammation
Diseases they cause are characterized by fecal cysts and trophozoites
The active, motile feeding stage of a sporozoan parasite
Entamoeba histolytica
Common in subtropical and tropical countries
They reside in the large intestine, and are usually harmless, feeding on bacteria
Complications can cause
Amebic dysentery is characterized by blood and pus in the stool
If the parasite perforates the intestine, peritonitis can result
Trophozoites can enter the bloodstream and spread to the liver or brain forming cysts and abscesses
Giardia lamlia
Causes giardiasis
Affects the duodenum and causes severe gas, bloating, abdominal pain, and damage to the mucosa
The disease is usually mild and self-limiting, but chronic forms are not uncommon
Treatment is with Atabrine and Flagyl
Surgical Implications
Parasitic worms that make their way into the brain require craniotomy for removal, liver or lung abscesses require I&D
Periodontitis may require surgery, if general anesthesia is needed the procedure would be performed in the OR
Skin
Chapter 29
Microbiology for Surgical Technologists
Anatomy of the Skin
Is the first line of defense against infection, irritants, and UV rays from the sun
Weighs about 6 lbs and gets about 1/3 of the blood circulating through the body
Is waterproof but can regulate the internal temp of the body by releasing water
Consists of two layers: epidermis and dermis
Anatomy of the Skin
(continued)
The dermis is a dense connective tissue that connects the skin to the tissues below (adipose and muscle)
It contains nerves and blood vessels
The hair follicles, oil gland ducts, and sweat gland ducts provide pathways for pathogens to enter skin and infect the tissue
Anatomy of the Skin
(continued)
The epidermis and dermis combined make up the cutaneous tissue
The layer beneath the cutaneous tissue is the subcutaneous layer
Anatomy of the Skin
Resident Flora
The skin is covered with microorganisms that make up the normal flora
Proper washing can remove and control growth, but complete removal is impossible
Skin can be surgically clean but is never sterile
Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium can be found anywhere on the skin
Resident Flora
(continued)
Cornybacteria are found primarily in moist areas such as armpits and between the legs
Others include Gram-positive organisms such as bacillus, diphtheroids, mycobacterium, micrococci, streptococci, and yeast
Gram-negative bacilli can also be found on the skin
Bacterial Infections of the Skin
Skin lesions
Vesicles are small fluid filled lesions
Vesicles larger than 1 cm are called bullae
Flat, reddened lesions are called macules
Raised, pus filled lesions are pustules
An ulcer is a skin depression where the epidermis and a portion of the dermis have been destroyed
Common in pressure areas on bedridden pts
Pressure Sores
Pressure Sores
Pathogens and Diseases
Of the Skin
Previously Discussed Diseases
Staphylococcus aureus
Causes cellulitis, folliculitis, boils
Streptococcus pyogenes
Cause TSS, necrotizing fasciitis, pharyngitis
Pseudomonas aeruginosa
Acquired in swimming pools and saunas
Mycobacterium leprae
Leprosy (Hansen’s disease)
Acne
Caused by Propionibacterium acnes, Staphylococcus aureus, and Corynebacterium spp
Characterized by inflammatory pustules, cysts, and papules
Most teenagers have some form of the disease
Can be triggered by fluctuating hormones
The most severe form is cystic acne
Leaves scars on the face and upper body
Acne
(continued)
Characterized by blocked sebaceous glands
Sebum accumulates and causes whiteheads
Blackheads are whiteheads that have dirt on them
The P. acnes metabolizes the sebum and leads to inflammation
White blood cells and fluid accumulate creating cysts that rupture and cause scarring
Acne
Fungal Infections of the Skin
Called cutaneous mycoses or dermatomycoses
Can invade skin, hair, and nails
Typically affect only the outer, dead layer of skin and rarely grow into deeper regions
Sometimes secretes toxic substances in the dermal area causing redness
Fungal Infections of the Skin
(continued)
Infected areas contain hyphae and spores
Spread easily through from person to person through skin contact
Pathogens include: Nicrosporum, Epidermophyton, and Trichophyton
Fungal Infections of the Skin
(continued)
Ringworm appears as a red ring around a white scaly region
Infections of the hair and scalp are called tinea capitis
Athelete’s foot is called tinea pedis
Jock itch is called tinea cruris
Nail fungus is tinea unguium
Tinea corporis affects the body
Fungal Infections of the Skin
(continued)
Viral Infections of the Skin
Can be as minor as warts or as serious as Smallpox
Warts are called papillomas and are caused by more than 50 types of papillomavirus
Chickenpox is caused by herpes virus varicella-zoster
Vesicles fill with pus, rupture and form scabs
Disease is self limiting and usually mild
Can cause encephalitis or pneumonia
Viral Infections of the Skin
(continued)
Varicella-zoster remains in the body for a lifetime after the initial infection
It lies dormant in the dorsal root ganglion near the spine
It can be reactivated by stress or againg and move into superficial sensory nerves resulting in a painful condition known as Shingles (herpes zoster)
Exhibits lesions similar to Chickpox but more painful
Viral Infections of the Skin
(continued)
The rash is usually found only on one side of the body on the trunk, face, abdomen, arms or legs
The most common appears on the chest like half of a belt
Herpes Zoster
Herpes Zoster
Viral Infections of the Skin
(continued)
Smallpox is a serious disease that was virtually eradicated by vaccination and the fact that the disease has no animal reservoir
Samples exist in Russia and the US and debate continues as to whether these samples should be destroyed before they fall into terrorist hands
Viral Infections of the Skin
(continued)
The disease is caused by two forms of the variola virus
Variola major has a 20% mortality rate
Variola minor has a >1% mortality rate
Transmitted by respiratory aerosol
From the lungs it infects internal organs and is carried through the blood to the skin, forming characteristic lesions
Smallpox
Surgical Implications
Cystic acne may require dermabrasion to remove skin and reduce scar tissue
Genital and anal warts are often removed with a laser in the OR. Special laser filter masks and goggles should be worn by all personnel in the room and a smoke evacuator used. The virus can be inhaled from the smoke plume and lodge in the lungs forming lesions
Homework
Case Study 2
Page 311
Words of Wisdom
No one has more potential for greatness than any one else.
Marianne Williamson
Chapter 28
Microbiology for Surgical Technologists
The Digestive Tract
Basic Anatomy
The digestive tract is a long tube that begins at the mouth and ends at the anus
Digestion is helped with accessory organs that include the teeth, salivary glands, liver, gallbladder, and pancreas
It begins in the mouth where the food is ground by the teeth and mixed with saliva
Saliva contains two enzymes
Amylase – breaks down carbohydrates into simple sugars
Lysozyme – destroys bacteria, protecting mucous membranes from infection and teeth from decay
The food is then swallowed and passes through the esophagus into the stomach
The stomach secretes pepsinogen and hydrochloric acid which combine to produce pepsin
Pepsin is the enzyme that breaks down protein
The stomach churns and contracts to help the enzymes break the food down into smaller particles
The food then passes into the small intestines which are divided into three sections
Duodenum
Jejunum
Ileum
The pancreas secretes the enzymes lipase, carbohydrase and protease which break down fats, carbohydrates and proteins
It also secretes the hormones glucagon and insulin that regulate and control blood sugar levels
The liver produces bile salts that break down fats
The gallbladder contains bile produced by the liver, it stores and concentrates it until it is needed
About 80% of nutrient absorption occurs in the small intestine
The food is then moved into the large intestine through the ileocecal valve
The large intestine (colon) is divided into three sections
The ascending colon, transverse colon, and descending colon
The main function of the colon is to absorb water
The food then passes into the sigmoid colon and rectum and is expelled from the anus
The Colon
Resident Flora
The GI tract contains a lot of resident flora
The mouth contain large amounts of bacteria, whereas the stomach and upper small intestine do not
Why?
The lower small intestine and the colon contain most of the resident flora
The colon contains approx 100 billion bacteria per gram of feces
Alcohol and simple sugars can alter the environment of the colon
Alcohol can kill resident flora and sugar can feed unfavorable bacteria disrupting the ratio of friendly and unfriendly bacteria
Antibiotics kill the pathogenic bacteria that they were designed for but can also destroy the favorable flora
Pathogens and Diseases
Of the GI Tract
Dental Caries
Teeth come into contact with large amounts of bacteria causing dental plaque and decay
Oral bacteria convert sugars into lactic acid which eats away at tooth enamel
The bacterium that causes the most damage is Streptococcus mutans
Dental Caries
Dental Caries
Dental Caries
Gingivitis/Periodontitis
Gingivitis is an infection of the gums, characterized by bleeding an sore gums
If left untreated it can progress into a chronic condition called periodontitis
Pus pockets form around the teeth destroying bone and tissue that anchor the teeth
Caused primarily by the Porphyromonas species
Acute necrotizing ulcerative gingivitis (trench mouth) is a serious infection causing bleeding, pain and difficulty with chewing
Caused by Prevotella intermedia
Periodontitis
Neglected Teeth Before Cleaning
Neglected Teeth After Cleaning
Shigellosis
Also known as
Shigellosis
Caused by the exotoxin of Shigella dysenteriae
Typically acquired through the fecal-oral route
Symptoms include:
Bloody diarrhea with mucous and pus, nausea and vomiting, fever, and convulsions
Treatment
Fluid and electrolyte replacement
Antibiotic therapy
The 4 F’s of Food Poisoning
Food
Fingers
Flies
Feces
Previously Discussed Diseases
Escherichia coli
Traveler’s diarrhea
Staphylococcus enterotoxicosis
Caused by S. aureus
Food handlers can rub their nose and infect food
Clostridium botulinum
Causes botulism
Salmonella
Parasites of the GI Tract
The intestinal tract is home to many species of protozoa and worms
Most of those that cause disease are acquired through the fecal-oral route
Some worm larvae can penetrate the skin and make their way to the GI tract
Infected animals can be eaten and infect people
Protozoan pathogens include Entamoeba histolytica, Giardia lamblia, and Cryptosporidium
Symptoms can be acute or chronic, with mild to severe diarrhea and inflammation
Diseases they cause are characterized by fecal cysts and trophozoites
The active, motile feeding stage of a sporozoan parasite
Entamoeba histolytica
Common in subtropical and tropical countries
They reside in the large intestine, and are usually harmless, feeding on bacteria
Complications can cause
Amebic dysentery is characterized by blood and pus in the stool
If the parasite perforates the intestine, peritonitis can result
Trophozoites can enter the bloodstream and spread to the liver or brain forming cysts and abscesses
Giardia lamlia
Causes giardiasis
Affects the duodenum and causes severe gas, bloating, abdominal pain, and damage to the mucosa
The disease is usually mild and self-limiting, but chronic forms are not uncommon
Treatment is with Atabrine and Flagyl
Surgical Implications
Parasitic worms that make their way into the brain require craniotomy for removal, liver or lung abscesses require I&D
Periodontitis may require surgery, if general anesthesia is needed the procedure would be performed in the OR
Skin
Chapter 29
Microbiology for Surgical Technologists
Anatomy of the Skin
Is the first line of defense against infection, irritants, and UV rays from the sun
Weighs about 6 lbs and gets about 1/3 of the blood circulating through the body
Is waterproof but can regulate the internal temp of the body by releasing water
Consists of two layers: epidermis and dermis
Anatomy of the Skin
(continued)
The dermis is a dense connective tissue that connects the skin to the tissues below (adipose and muscle)
It contains nerves and blood vessels
The hair follicles, oil gland ducts, and sweat gland ducts provide pathways for pathogens to enter skin and infect the tissue
Anatomy of the Skin
(continued)
The epidermis and dermis combined make up the cutaneous tissue
The layer beneath the cutaneous tissue is the subcutaneous layer
Anatomy of the Skin
Resident Flora
The skin is covered with microorganisms that make up the normal flora
Proper washing can remove and control growth, but complete removal is impossible
Skin can be surgically clean but is never sterile
Staphylococcus epidermidis, Staphylococcus aureus, and Propionibacterium can be found anywhere on the skin
Resident Flora
(continued)
Cornybacteria are found primarily in moist areas such as armpits and between the legs
Others include Gram-positive organisms such as bacillus, diphtheroids, mycobacterium, micrococci, streptococci, and yeast
Gram-negative bacilli can also be found on the skin
Bacterial Infections of the Skin
Skin lesions
Vesicles are small fluid filled lesions
Vesicles larger than 1 cm are called bullae
Flat, reddened lesions are called macules
Raised, pus filled lesions are pustules
An ulcer is a skin depression where the epidermis and a portion of the dermis have been destroyed
Common in pressure areas on bedridden pts
Pressure Sores
Pressure Sores
Pathogens and Diseases
Of the Skin
Previously Discussed Diseases
Staphylococcus aureus
Causes cellulitis, folliculitis, boils
Streptococcus pyogenes
Cause TSS, necrotizing fasciitis, pharyngitis
Pseudomonas aeruginosa
Acquired in swimming pools and saunas
Mycobacterium leprae
Leprosy (Hansen’s disease)
Acne
Caused by Propionibacterium acnes, Staphylococcus aureus, and Corynebacterium spp
Characterized by inflammatory pustules, cysts, and papules
Most teenagers have some form of the disease
Can be triggered by fluctuating hormones
The most severe form is cystic acne
Leaves scars on the face and upper body
Acne
(continued)
Characterized by blocked sebaceous glands
Sebum accumulates and causes whiteheads
Blackheads are whiteheads that have dirt on them
The P. acnes metabolizes the sebum and leads to inflammation
White blood cells and fluid accumulate creating cysts that rupture and cause scarring
Acne
Fungal Infections of the Skin
Called cutaneous mycoses or dermatomycoses
Can invade skin, hair, and nails
Typically affect only the outer, dead layer of skin and rarely grow into deeper regions
Sometimes secretes toxic substances in the dermal area causing redness
Fungal Infections of the Skin
(continued)
Infected areas contain hyphae and spores
Spread easily through from person to person through skin contact
Pathogens include: Nicrosporum, Epidermophyton, and Trichophyton
Fungal Infections of the Skin
(continued)
Ringworm appears as a red ring around a white scaly region
Infections of the hair and scalp are called tinea capitis
Athelete’s foot is called tinea pedis
Jock itch is called tinea cruris
Nail fungus is tinea unguium
Tinea corporis affects the body
Fungal Infections of the Skin
(continued)
Viral Infections of the Skin
Can be as minor as warts or as serious as Smallpox
Warts are called papillomas and are caused by more than 50 types of papillomavirus
Chickenpox is caused by herpes virus varicella-zoster
Vesicles fill with pus, rupture and form scabs
Disease is self limiting and usually mild
Can cause encephalitis or pneumonia
Viral Infections of the Skin
(continued)
Varicella-zoster remains in the body for a lifetime after the initial infection
It lies dormant in the dorsal root ganglion near the spine
It can be reactivated by stress or againg and move into superficial sensory nerves resulting in a painful condition known as Shingles (herpes zoster)
Exhibits lesions similar to Chickpox but more painful
Viral Infections of the Skin
(continued)
The rash is usually found only on one side of the body on the trunk, face, abdomen, arms or legs
The most common appears on the chest like half of a belt
Herpes Zoster
Herpes Zoster
Viral Infections of the Skin
(continued)
Smallpox is a serious disease that was virtually eradicated by vaccination and the fact that the disease has no animal reservoir
Samples exist in Russia and the US and debate continues as to whether these samples should be destroyed before they fall into terrorist hands
Viral Infections of the Skin
(continued)
The disease is caused by two forms of the variola virus
Variola major has a 20% mortality rate
Variola minor has a >1% mortality rate
Transmitted by respiratory aerosol
From the lungs it infects internal organs and is carried through the blood to the skin, forming characteristic lesions
Smallpox
Surgical Implications
Cystic acne may require dermabrasion to remove skin and reduce scar tissue
Genital and anal warts are often removed with a laser in the OR. Special laser filter masks and goggles should be worn by all personnel in the room and a smoke evacuator used. The virus can be inhaled from the smoke plume and lodge in the lungs forming lesions
Homework
Case Study 2
Page 311
Words of Wisdom
No one has more potential for greatness than any one else.
Marianne Williamson
posted by Ms. Carpenter | 10:17 AM
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