1. streptococcal pharyngitis

2. Diphtheria

3. acute bacterial meningitis 

• caused by streptococcus pyogenes 
• Structure:
• Group A strep
• M protein destabilizes C3 convertase
• Hyaluranic acid evade WBCs
• Toxins
• Hemolysis breaks down RBCs
• streptokinases dissolve blood clots
• Erythrogenic toxins result in Scarlet Fever 

1. Scarlet fever

2. Rheumatic fever

3. Acute glomerularnephritis 

Caused by Corynebacterium diphtheriae 

• transmitted by droplet inhalation 
• sore throat/fever
• pseudomembrane forms and impairs breathing
• Toxoid vaccine against diphtheria toxin 

• localized infection spreads to blood and meninges 
• triad of symptoms
• fever, headache, stiff neck 
• nausea, vomit, sensitivity to light
• coma and death
• caused by:
• neisseria meningitis
• streptococcus pneumoniae 
• haemophilus influenzae type b 

1. Pertusis 

2. Tuberculosis

3. Pneumonia  

Pertusis 

caused by bordatella pertusis 

• spread by respiratory droplets 
• 2 stages
• Catarrhal - low grade fever and cough
• Paroxysmal - labored breathing, paroxysms 
• 
  low incidence due to DTaP vaccine
• reemerging becaues of increased virulence  

Tuberculosis 

caused by mycobacterium tuberculosis 

• acid fast bacterium
• capacity for intracellular growth 
• spread by aerosol droplets, low infectious dose

• causes are streptococcus pneumoniae  and Haemophilus influenzae 
• endogenous or exogenous acquisition 
• productive colored sputem, fever, chest pain 

Primary atypical pneumonia

walking pneumonia 

caused by mycoplasma pneumoniae 

• no cell wall, pleomorphic shape
• smallest free living bacteria
• exogenous acquisition 
• mild symptoms

legionnaires disease

(atypical pneumonia)

caused by legionella pneumophila

• exists where water collects
• effects elderly or immunocompromised 
• not transmitted person to person 

caused by streptococcus mutans 

• initiates formation of biofilm plaque
• forms glycocalyx enabling attachment to tooth ennamel 
• other species adhere via fimbriae forming biofilm
• may turn into calculus 
• periodontal disease may lead to sepsis and heart damage 

noninflammatory gastroenteritis 

Staphylococcal food poisoning, clostridial food poisoning, botulism 

caused by staphylococcus aureus 

• food contamination during prep.
• produce heat stabile exotoxins (enterotoxins)
• ingestion of toxins trigger symptoms in 1-6 hours

caused by clostridium perfringens 

• endospore forming obligate anaerobe dwells in soil and GI
• endospores survive cooking and germinate
• produce heat labile enterotoxin 
• symptoms onset 8-24 hours after ingestion 

caused by clostridium botulinum

• endospore forming obligate anaerobe found in soil and GI
• endospores germinate in anaerobic environment
• relase botulism neurotoxin inhibiting release of ACh
• onset of symptoms 12-24 hours
• blurred vision, slurred speach, hard to swallow
• paralysis 
• death from resp. failure 

inflammatory gastroenteritis 

Cholera 

other vibrio species

ETEC

Clostridium difficile 

caused by vibrio cholerae 

• raw oysters and water
• requires high infectious dose because of low resistnace to stomach acidity
• rice water stool, toxin causes loss of water and electrolytes 

infection from raw shellfish

v. parahymolyticus

v. vulnificus 

• transmitted via fecal oral route
• travelers diarrhea 
• produces two enterotoxins, 1 similar to cholera toxin

• elderly and long term abx users 
• often acquired at health care facilites 
• treat by stopping abx and fecal transplant

invade deep layers of GI 

Salmonellosis

Typhoid

Shigellosis

EHEC

Campylobacter jojuni

caused by Salmonella enterica 

• in intestines/feces of birds, reptiles, mammals
• most infections due ot reptile feces, poultry, eggs
• non bloody diarrhea, vomit, fever, cramps

caused by salmonella typhi

• humans are only host
• carriers can be asymptomatic, gall bladder
• fecal oral transmission route
• leads to systemic illness 

caused by variety of Shigella species 

• parasite of humans
• causes bacillary dysentery (bloody stool)
• most virulent is s. dysenteriae 
• produce shiga toxin that stops protein synth. in host cell

E. Coli 0157:H7

• some cows have this in thier normal flora
• fecally contaminated raw beef, unpasteurized milk, vegetables, fruit juice
• produces shiga like toxin 
• cause diarrhea, hemmorhagic colitis, hemolytic uremic syndrome (kidney disease)

campylobacter jojuni

• most common bacterial gastroenteritis in USA
• fecal oral transmission, usually by chicken 
• mild to severe symptoms 

caused by Helicobacter pylori

• transmitted person to person
• causes stomach ulcers 

Anthrax

Tetanus 

Gas Gangrene 

caused by bacillus anthracis 

• forms endospores, dwells in soil and GI
• 3 different toxins produced
• route of exposure determines disease
• cutaneous anthrax
• gastrointestinal anthrax
• inhalation anthrax 

• endospores enter through break in skin
• produces ulcer called eschar
• 20% fatality rate if untreated 

• endsospores concentrated via contaminated meat
• results in intestinal hemorhaging 
• fatality 25-60%

• endospores inhaled via animal hides/fur
• initial symptoms resemble common cold
• septicemia results in shock 
• faltality about 100%

caused by clostridium tetani 

• obligate anaerobe forms endospores, dwell in soil and GI
• endospores germinate in wounds
• releases tetanospasmin, inhibits muscle relaxing
• toxemia results in lockjaw
• death from resp. failure
• treatment wiht toxoid vaccine, antitoxin, abx
• boosters for vaccine 

Gas Gangrene 

caused by clostridium perfringens 

• trauma introduces endospores into body where they germinate in anaerobic tissue 
• releases variety of exotoxins (hyaluranidase)
• gases, odor, black color
• treatment with abx, debridement, amputation, and hyperbaric chamber 

plague

lyme disease

rocky mountain spotted fever

caused by yersinia pestis 

• rodents are reservoir 
• transmitted to humans by fleas 
• 3 forms 
• bubonic plague
• septicemic plague
• pneumonic plague 

Bubonic plague

• bacteria grows in lymph nodes (bubos)
• rapid progression
• untreated, fatality = 50%

bacteria grow in bloodstream 

may result in meningitis or pneumonic plague 

• human to human transmission, highly contagious
• symptoms appear as soon as 3 hours 
• 100 % fatal 

caused by borrelia burgdorferi 

• field mice are reservoir
• transmitted to humans via deer ticks
• 3 stages of disease 
• early localized 
• bulls eye rash in 80% of cases
• flu like symptoms 
• early disseminated
• neurological symptoms (meningitis, encephalitis) and cardiac dysfunction
• late stage
• months to years later 
• chronic arthritis due to autoimmune disease 

caused by Rickettsia rickettsii 

• ticks are reservoir
• transmitted to humans by adult form
• fever, headache and rash
• may be fatal 

caused by chlamydia trachomatis 

• very small, no cell wall
• obligate intracellular parasite 
• 2 forms
• elementary body
• non replicating
• extra cellular
• infectious
• reticulate body 
• replicating
• intra cellular
• non-infectious

caused by nongonococcal urethritis

• 85% asymptomatic
• painful urination and slight discharge
• females may progress to PID
• inflammation of uterus, fallupian tubes, ovaries
• may cause sterility

• conracted by newborns from mother during birth
• may lead to blindness

caused by neisseria gonarheae

• gram negative diplococcus 
• fimbriae enable attachment to epithelia 
• males
• painful urination and pus filled discharge
• females
• PID and sterility  

caused by temponema pallidum

• spirochete with endoflagella
• humans only host
• primary
• chancre (painless ulcer) forms at infection site
• highly infectious
• secondary
• weeks after primary resolves
• flu like symptoms with rash "great pox"
• lesions are infectious 
• latent
• may have relapses of secondary for up to 4 years 
• tertiary
• 40% obtain if untreated
• degeneration of organs
• gummas - painful, swollen infectious lesions

spirochetes infect newborns

stillbirth may result

• normally reside on skin and nasal passages
• structural components and virulence factors contribute to disease 
• Protein A on cell surface
• interferes humoral response by binding to IgG
• inhibit complement cascade
• capsules inhibit phagocytosis 
• enzymes
• catalase 
• coagulase
• staphylokinase
• hyalurinadase
• Beta - lacteinase
• toxins
• leukocidins
• exfoliative toxins
• toxic shock syndrome
• 4 diseases

catalase

• infection of hair follicles
• sty - eye
• furuncle - boil
• carbuncle - several furuncles

release of exfoliative toxin

epidermis peels off

superantigen in blood

fever, vomitting, rash, BP drop

death from shock

causes erysipelas and necrotizing fascitis

1. severe pain, swelling and redness at infection site
2. fever
3. toxemia results in death
4. same treatment as gas gangrene

• bacteria reach subcutaneous tissue through trauma
• enzymes and toxins destroy tissue
• bacteria spreads along fascia (along muscle)

myobacterium leprae

• obligate intracellular parasite
• human to human transmission, low contageous 
• grows at 30 C
• tuberculoid
• loss of sensation in extremeties
• lepromatous
• tissue destruction and loss of limbs
• lepromas - tumor like growth