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Bacterial Diseases
- Are usually airborne
- Affect respiratory system
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Upper respiratory system
Everything above the vocal cords (larynx)
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Upper Respiratory Diseases
- Streptococcus
- Meningococcus Meningitis
- Haemophilus Meningitis
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Pharyngitis
- Sore throat
- Usually a symptom of a viral infection, but some bacteria, especially streptococci can cause this
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Streptococcus
- Alpha hemolytic
- Beta hemolytic
- Gamma hemolytic
- Groups A-O
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Physical attributes of Streptococcus
- Gram+
- Sphere shaped chains
- Small bright white colonies
- Encapsulated
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Streptococci can be divided into two groups, based on how they affect sheep red blood cells
- alpha-hemolytic
- beta-hemolytic
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Beta-hemolytic streptococcus
Complete destruction of red blood cells (hemoglobin)
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Serotyping
- Surface anogen
- Groups A-O
- They can also be classified according to variants of a carbohydrate in the cell wall
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What is the most common streptococcus?
Streptococcus pyogenes
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Streptococcus pyogenes characteristics
- G+
- Group A Beta Hemolytic
- Encapsulated chains
- Common in the nose and throat
- Puerperal sepsis (child bed fever)
- Septicemia
- Erysipelas
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What enhances Streptococcus pyogenes
- The pathogenicity of S. pyogenes is enhanced by M protein, which helps it:
- adhere to pharyngeal tissue
- retard phagocytosis
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What is Erysipelas
- Deadly pustules on the skin caused by Streptococcus pyogenes.
- Found on chickens, pigs and humans
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Streptococcal sore throat characteristics
- Caused by S. pyogenes
- Contains M protein which increases the ability the bacteria to attach to the throat (pharynx)
- 60 types. You can only get each one once
- 500000 cases per year
- Becoming antibiotic resistant
- Was deadly before antibiotic
- Primary disease - can cause disease in healthy tissue
- Spread by airborne droplets
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Streptococcal Pharyngitis sore throat symptoms
- Take 1-3 days to develop
- High fever
- Swollen lymph nodes
- Red pharyngeal ring tissue
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Streptococcal Pharyngitis Treatment
Treat with antibiotics
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Scarlet Fever
- Some patients with strep throat may develop scarlet fever, exhibiting a rash caused by erythrogenic exotoxins
- Other symptoms are sore throat, fever, strawberry-like inflamed tongue.
- Normally only get this once in a lifetime because recovery generates immunity.
- Get better in 2 weeks without treatment.
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Scarlet fever treatment
- Treat with antibiotic and antitoxin
- Antibiotics can shorten duration of the symptoms and prevent serious complications.
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Erythrogenic exotoxins
- In Scarlet Fever, the toxins produced by the bacteria cause a pink-red skin rash on the neck, chest, and soft skin areas of the arms.
- The rash usually occurs in children under the age of 15.
- Caused by blood leaking through the walls of capillaries damaged by toxins
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Exotoxin
Poisonsous proteins secreted by some G+ and G- bacteria
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Rheumatic fever
- A serious complication of scarlet fever
- Most common in young school aged children
- An inflammation response to the infection that primarily affects joints and heart
- Fever and joint pain
- Causes permanent scarring and distortion of the heart valves called rheumatic heart disease
- This is caused by the body's antibodies to streptococcal M proteins cross reacting with similar proteins in the heart muscle.
- A serious problem in developing nations
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Acute glomerulonephritis
- A complication from streptococcal pharyngitis
- A rare inflammatory response to specific types of streptococcal M proteins
- The antigen-antibody complexes formed accumulate in the glomerulus of the kidney.
- Most common in young patients
- Progressive, irreversible renal damage may occur in adults
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Glomerulus
The part of the kidney that controls filtering and excretion.
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Diphtheria Characteristics
- Diphtheria is a local infection of the throat caused by Corynebacterium diphtheriae
- G+
- Aerobic
- Club shaped rod
- Coryne = club
- Metachromatic
- Not a lot of bacteria are present in the disease
- Damage caused by the exotoxin
- Diphtheria Is a Life-Threatening Illness
- There are usually less than a dozen confirmed cases in the U.S. each year
- Diphtheria is acquired by respiratory droplet transmission
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Diphtheria Symptoms
- Initial symptoms are sore throat and low-grade fever
- Pseudomembrane formation
- The exotoxin stops protein synthesis in the lining of tubes and forms a pseudomembrane on the tonsils or pharynx
- Mucus and coughing
- The bacterial cells remain in clumps after multiplying and form a picket fence like arrangement called a "palisade arrangement"
- Mild cases fade in a week
- Severe cases 2-6 weeks
- Untreated = 5-10% mortality rate
- Will damage nerves if you don't rest enough during recovery
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Diphtheria incubation
2-4 days
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Diphtheria exotoxin
- Encoded by a virus that infects C. Diphtheriae
- Inhibits the translation process by ribosomes resulting in the accumulation of dead tissue, mucus, white blood cells and fibrous material called a pseudomembrane.
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Diphtheria treatment
- Antibiotics - penicillin or erythromycin
- Antitoxin
- Before antibiotics, this would kill 50% of children who got it.
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Diphtheria vaccine
- Immunization with denatured diphtheria toxoid
- Part of the DTaP vaccine
- Makes you grow your own antitoxin
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Metachromatic granules
- Dark staining granules in bacteria
- Found in C. diphtheriae
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Prophage
- A virus that infects a bacteria
- C. diphtheriae is infected with a virus that cause it to create the exotoxin
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Pertussis
- Bordetella pertussis
- Per = through
- Tussi = cough
- Highly contagious upper respiratory infection
- Whooping Cough
- Also called the100 day cough
- Number of cases has been rising since 1981, possibly due to a more virulent strain and better lab testing
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Bordetella pertussis characteristics
- G-
- Small
- Aerobic
- Bacillus
- Spread by respiratory droplets that adhere to and aggregate on the cilia of the epithelial cells in the mouth and throat
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Pertussis statges
Two stages lasting 4-12 weeks
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Pertussis initial stage
- Catarrhal
- General malaise
- Low-grade fever
- Increasingly severe cough
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Pertussis second stage
- Paroxysmal stage
- Disintegrating cells and mucus accumulate in the airways and cause labored breathing
- Paroxysms - Rapid fire staccato coughs all in one exhalation followed by a forced inhalation over a partially closed glottis.
- The rapid inhalation results in the characteristic whoop
- 10-15 paroxysms occur daily each followed by exhaustion
- Sporadic coughing continues during convalescence even after pathogen disappears
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Pertussis treatment
- Antibiotics - erythromycin
- If treatment is begun before the respiratory passageways are block the bacteria is generally successful.
- Antibiotics only reduce the duration and severity of the illness
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Pertussis Vaccine
- The aP part of the DTaP vaccine
- Lose immunity 5-10 years after vaccination
- There are now boosters
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Meninges
The meninges are three membranous coverings of the brain and spinal cord
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Bacterial Meningitis
- Upper respiratory infection caused by
- Neisseria meningitides
- Streptococcus Pneumoniae
- Haemophilus influenza Type b
- All 3 species can cross the blood-brain barrier, inflaming the meninges
- This causes pressure on the brain and spinal cord
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How are the bacteria that cause meningitis acquired?
- Respiratory droplets from prolonged contact such as
- Coughing
- Sneezing
- Kissing
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Neisseria meningitides
- Causes meningococcal meningitis
- Spread through person-to-person transfer of droplet respiratory secretions
- Can cause meningococcal pharyngitis and then may invade into the nonciliated epithelium and spread to the blood
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Meningococcal Meningitis
- Neisseria meningitides
- G- encapsulated diplococcus
- Small, aerobic
- Attaches to the nasopharyngeal mucosa by pili
- Airborne droplets
- Influenza like respiratory disease
- Toxins can enter blood and cause death in 2 hours
- 50% mortality rate
- Forms 1 of 14 different serogroup capusules.
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Serogroup
A group of microbes having similar surface proteins (antigens)
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Meningococcal Meningitis
- Stiff arched neck, headache
- Rash on skin
- Bright red patches progressing to blue-black spots
- 50% mortality rate
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Meningococcal Meningitis Treatment
Antibiotics: rifampin, penicillin
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What is Waterhouse-Friderichsen syndrome?
- A complication of meningococcal meningitis in young childrens. Lesions form on the adrenal glands and cause hormone imbalances.
- Is the result of a bacterial endotoxin in the blood.
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Pneumococcal meningitis
- Caused by Streptococcus pneumoniae
- Community acquired
- Affects infants, middle aged and elderly adults
- Patients with an absent spleen, sickle cell disease, chronic alcoholism, and those with recent skull fractures or head injury are at high risk
- Responsible for ~30% of meningitis cases
- 20-30% mortality rate
- Haemophilus influenzae type b (Hib)
- G-, small, nonmotile, encapsulated, bacillus
- Was thought to cause influenza, but actually causes Haemophilus meningitis
- Used to be the most prevalent bacterial species causing meningitis in children 2 months to 5 years old
- Vaccine drastically reduced occurrence
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Richard Pfeiffer
- Isolated Haemophilus influenzae type b (Hib) during the flu epidemic of 1918
- Thought it caused flu but it was a secondary infection
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Haemophilus Meningitis
- Haemophilus influenzae type b
- G- encapsulated bacillus
- Secondary to influenza
- Most common form of meningitis
- Occurs in children 6-12 months
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Haemophilus Meningitis Symptoms
- Stiff neck
- Headache
- Drowsiness
- 18,000 cases a year in 1986 before vaccine
- 5% mortality rate
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Haemophilus Treatment and Vaccine
- HiB vaccine
- Antibiotic rifampin
- No single vaccine provides immunity to all causes of meningitis
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Meningitis can have the following lasting affects:
- deafness
- blindness
- paralysis
- if untreated it can lead to coma and death
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Lower respiratory diseases
- Tuberculosis
- Pneumococcal Pneumonia
- Klebsiella Pneumonia
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Tuberculosis
- Mycobacterium tuberculosis
- A major cause of death worldwide � 2 million people die every year globally
- Airborne droplets, multiple exposures
- Usually need repeated exposures
- A big problem for AIDS patients
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Tuberculosis Symptoms
- 10% have immediate symptoms (3 months)
- Chronic cough
- Chest pain
- High fever
- Rust colored sputum
- 90% will never develop an active infection
- Form tubercle
- Miliary TB: Consumption
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Primary TB infection
- The person has a pulmonary infection but may not yet have the disease
- Chest X-Ray and sputum test are negative
- Macrophages, lymphocytes and fibroblasts surround the mass forming a tubercle
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Tubercle
- Macrophages arrive in the lungs and attempt to phagocytize the Mycobacterium tuberculosis bacillus but are unable to destroy them.
- Macrophages, lymphocytes and fibroblasts surround the mass forming a hard nodule
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Latent TB infection
- The infection becomes arrested in 90 % of primary TB infections
- The tubercles heal and undergo fibrosis and calcification
- Carried by 2 billion people worldwide
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Primary active TB disease
10% of the people that have a primary TB infection will develop a clinical disease
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Secondary active TB disease
- Reactivation of the TB bacilli
- Unable to keep bacilli in check
- Many of the macrophages dies releasing he bacilli and producing a caseous (cheese-like) center in the tubercle
- Miliary tuberculosis
- Disseminated
- Active tubercles debelope throughout the body
- No toxins, but the growth is so unrelenting the respiratory and other body tissues are literally consumed
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Mycobacterium tuberculosis
- Neither G+ or G-
- Bacillus
- Use an acid fast stain
- Enters the respiratory tract in small aerosolized droplets
- Survives for years outside the body
- Tuberculosis is a particularly big problem for AIDS patients
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Clinical tuberculosis
- Develops within 3 months, and can be transmitted to others
- Macrophages accumulate in the lung form a tubercle that harbors M. tuberculosis
- If a tubercle breaks apart, bacteria spread throughout the body
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Miliary tuberculosis
The development of active tubercles throughout the body
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Mantoux test
The tuberculin reaction in the Mantoux test can be used for early detection of TB exposure
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Tuberculosis Vaccine
Attentuated M. bovis is used in immunization infrequently
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TB detection
- Tuberculin reaction, a delayed hypersensitivity test that begins with the application of a purified protein derivative (PPD) of M. tuberculosis to the skin
- Mantoux test � injection of PPD into forearm
- A positive test may indicate immunization, previous TB test or past exposure to Mycobacterium tuberculosis
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Induration
- A think, raised, red welt of a defined diameter
- In a TB test, if the welt is bigger than 15 mm the test is positive
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TB Treatment
- Antibiotics � Isoniazid and rifampin
- 5% of new cases are multidrug-resistant tuberculosis
- Multidrug-resistance Mycobacterium tuberculosis is affecting which antibiotics are used to treat TB
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Mycobacterium avium-intracellulare
- A bird form of TB
- Common in AIDS and Chemo patients and people with suppressed immune systems
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Pneumococcal Pneumonia
- Streptococcus pneumonia is the leading cause of both pneumonia and bacterial meningitis
- 80% of "typical" pneumonia cases are caused by Streptococcus pneumoniae
- It is acquired through aerosolized droplets or contact
- 40,000 deaths per year
- Lobar
- Double
- Bronchopneumonia
- Walking pneumonia
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Pneumococcal Pneumonia Symptoms
- Fever
- Chest Pain
- Difficult Breathing
- Rust-colored sputum
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Lobar pneumonia
1 lung lobe
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Double pneumonia
Both lungs
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Bronchopnuemonia
Patches in the respirator passageways
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Pneumonia treatment
- penicillin
- tetracycline
- Chloramphenical � last resort. Very hard on liver and kidneys
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Pneumonia vaccine
80 strains known, vaccine for 23 strains
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Other causes of pneumonia
- Haemophilus influenzae
- Staphylococcus aureus
- Klebsiella pneumoniae
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Haemophilus influenzae can cause:
- "Typical" pneumonia
- Otitis media sinusitis
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Staphylococcus aureus
- A common hospital-acquired form of pneumonia
- It may result in necrotizing pneumonia
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Klebsiella pneumoniae
- can be a primary or secondary infection in people with impaired pulmonary function
- G- encapsulated bacillus
- 5% of bacterial pneumonia
- Spread by airborne droplets
- Common noscomial disease
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Noscomial disease
Disease acquired in the hospital
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Atypical Pneumonia
- Can Be Caused by a Diverse Group of Bacterial Species
- Mycoplasma pneumoniae causes primary atypical pneumonia, often called walking pneumonia
- Mycoplasma. pneumoniae has no sensitivity to penicillin because it has no cell wall
- The cold agglutinin screening test (CAST) is used to assist diagnosis
- Has "fried-egg" colony appearance
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Legionnaires disease
- Causes a severe atypical pneumonia
- Headache
- Dry cough
- Some diarrhea and vomiting
- Treated with Erythromycin
- Exists where water collects and then becomes airborne in wind or breezes
- Disease develops within a week of inhalation of contaminated droplets
- Necrotizing pneumonia may develop
- L. pneumophila also causes Pontiac fever, an influenza-like infection
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Q Fever
- Coxiella burnetii
- G- bacillus
- World wide
- Affects livestock so outbreaks occur where animals are raised, housed or transported
- Can get from raw milk or cheese
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Q Fever Symptoms
- Bronchopneumonia
- Severe headache
- High fever
- Dry cough
- Occasional lung lesions
- Q Fever Treatment
- Antibiotic doxycycline
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Q Fever vaccine
Available for high-risk occupations
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