1. What diseases are caused by bacteria?

2. Overview of Bacterial Infectious Diseases
Skin and Soft Tissue Infections
Ocular Infections
Upper and Lower Respiratory Tract Infections (URTI, LRTI)
Infections of Central Nervous System (CNS)
Bacteremia and Sepsis
Gastrointestinal (GI) Infections
Urinary Tract Infection (UTI) and Sexually Transmitted Diseases (STD)

3. Skin and Soft Tissue Infections
Staphylococcus aureus
Streptococcus pyogenes
Propionibacterium

4. Invasive Skin Disease: Staphylococcus
Characterized by pus production
Pimples – infection of hair follicles (folliculitis); if eyelash disease called sty
Furuncles (boils) – abscess develops from pimple, characterized by pus surrounded by inflamed tissue
Carbuncles - series of interconnected furuncles with more extensive tissue invasion
Septicemia – from carbuncles, MO spread to bloodstream
May also cause impetigo in newborns (see Streptococcus)

5. Skin Disease By Toxin: Staphylococcuss
Scalded skin syndrome:
produces a cytotoxin, exfoliative or epidermolytic toxin
causes outer skin to peel away in layers
Toxic shock syndrome:
exfoliation of skin may occur also
involving tampon use in menstruating women
due to toxic shock syndrome toxin, type I

6. Invasive Skin Disease: Streptococcus
Impetigo – pustules become crusted and rupture, very contagious, easily spread from child to child in day care setting
Wound infections – occasional infections following trauma, usually due to contamination of wound
Cellulitis – subcutaneous tissue, may be accompanied by lymphangitis and abscess formation

7. Invasive Skin Disease: Streptococcus
Nectotizing fasciitis – destruction of fiberous tissue deep in skin including destruction of sheath tissue that covers muscle (“flesh eating bacteria”)
Myositis – invasion of muscle tissue resulting in extensive muscle necrosis and overwhelming sepsis, usually fatal

8. Skin Disease By Toxin: Streptococcus
Rash seen in Scarlet fever due to erythrogenic toxin

9. Skin Disease By Toxin: Streptococcus
Erysipelas – diffuse, erythematous skin disease due to exotoxin, most often on face following pharyngitis

10. Ocular Infections Conjunctivitis Gonococcal opthalmia neonatorum
Tracoma

11. Conjunctivitis By many different MOs
Infection of membranes cover eye and lining of eyelid
By many different MOs
Contagious conjunctivitis (pinkeye) Haemophilus aegyptius
Gonococcal opthalmia neonatorum
Neisseria gonorrhoeae
Transmitted to newborns as baby moves through birth canal
Prevented by giving all newborns eye drops containing antibiotics at birth

12. Trachoma Chlamydia trachomatis Transmitted by direct contact
Single most common cause of blindness in developing countries

13. Upper & Lower Respiratory Tract Infections
Pharyngitis
Diphtheria
Otitis Media
Whooping cough
Tuberculosis
Pneumonia

14. Pharyngitis Sore throat
Mainly by Streptococcus pyogenes (classic “Strep throat”)
Transmitted by respiratory secretions
Symptoms include inflammation of throat and fever
Leads to tonsilitis and middle ear infections

15. Diphtheria
Corynebacterium diphtheriae lysogenized by phage encoding “tox” gene
Starts with sore throat, fever, followed by general malaise and swelling of neck
Tough grayish membrane form in throat, can cause suffocation
Bacteria not invasive, liberate exotoxin, death may occur due to effect on heart and kidneys
D part of DPT vaccine

16. Otitis Media (middle ear infection)
Uncomfortable complication of common cold or any infection of nose or throat
More common in children because auditory tube so small
Most commonly:
Streptococcus pneumoniae
Haemophilus influenzae
Streptococcus pyogenes
Staphylococcus aureus
Moraxella catarrhalis

17. Whooping Cough Bordetella pertussis
Transmitted by respiratory secretions
MO not invasive, attaches to respiratory epithelia impeding action, causes build-up of mucous
Disease occurs in 3 stages
Catarrhal stage - symptoms similar to common cold
Paroxysmal stage – characterized by prolonged sieges of coughing as patient tries to get rid of mucous built up; gasping of air occurs between coughs causing a “whooping” sound, 1-6 weeks
Convalescent stage – several months
P part of DPT vaccine

18. Tuberculosis
Mycobacterium tuberculosis and Mycobacterium bovis can cause Tb, but M. bovis rare in U.S.
MO gain entrance by many portals of entry with inhalation being most common
Tubercle bacilli reach alveoli of lung are ingested by macrophages
Enzymes and cytokines release to start inflammatory response to wall off MO (tubercle formation), but inflammatory response also causes lung damage

19. Tuberculosis
After few weeks macrophages die, releasing tubercle bacilli forming caseous center inside tubercle
In healthy individuals, disease usually arrested at this time and lesions become calcified; tubercle bacilli remain dormant in lesion and serve as a basis for later reactivation of disease
When host defenses fail, mature tubercle form and bacilli multiply
Tubercle eventually ruptures, releasing bacilli that disseminate throughout body
This is progressive form of disease and symptoms include weight loss, coughing with blood, and loss of vigor

20. Pneumonia Characterized by fever, difficult breathing, and chest pain
Many different MOs
Streptococcus pneumoniae – usually occurs following primary infection elsewhere
Klebsiella pneumoniae – permanent lung damage often occurs
Mycoplasma pneumoniae – “walking pneumonia” because individuals often do not know have disease, also called atypical pneumonia because cough not productive
Legionellosis – Legionella pneumophilia, transmitted by aerosols from contaminated water into air condition system, more common in older males

21. Infections of CNS Meningitis Tetanus Botulism
Hansen’s Disease (Leprosy)

22. Meningitis: Neisseria
Meningitis many different bacteria, most by:
Neisseria meningitidis
Starts as sore throat, progresses to bacteremia, then meningitis characterized by severe headache, neck and back pain, stiffness
Endotoxin (Gram-negative MO) causes extensive blood vessel damage with petechiae being hallmark symptom
Vaccine against most common encountered virulent types
College students living in dorms required/recommended to be vaccinated

23. Meningitis: Other MOs Haemophilus influenzae – have type b capsule
Common in children two months to four years
Today Hib vaccine prevents most infections
Streptococcus pneumoniae
Occurs immunocompromised, very young, very old
High mortality rate
Vaccine to prevent pneumonia is for >30 capsular types
E coli, type K1 and Streptococcus agalactiae –
Two most common cause of this disease in newborns
Mortality rate is high

24. Tetanus Cramps and twitching of muscles around wound
Clostridium tetani, neurotoxin tetanospasmin.
Spores found in feces, soil, dust; enter body by penetrating wound, germinate into vegetative cells, produce toxin
Cramps and twitching of muscles around wound
Headache and neck stiffness
Followed by trismus (lockjaw) and more generalized symptoms
Death, if occurs, results from respiratory failure

25. Botulism Neurotoxin produced by Clostridium botulinum
In the U.S., usually occurs following ingestion of toxin in inadequately processed home-canned food
First symptoms include nausea, vomiting, and diarrhea
Followed by symmetric, descending paralysis (eyes, throat, neck, trunk, and then the limbs)
Death is from respiratory failure

26. Hansen’s Disease (Leprosy): Tuberculoid
Mycobacterium leprae
Contagious but requires prolonged, fairly intimate contact
Two major forms of the disease
Tuberculoid – characterized by lesions of skin that have lost sensation

27. Hansen’s Disease: Lepromatous
Characterized by disfiguring nodules that form mainly on colder areas of body
Death occurs from complications of other bacterial infections

28. Bacteremia and Sepsis Septicemia Endocarditis Rheumatic fever
Tularemia
Brucellosis
Anthrax
Plague
Relapsing fever
Lyme disease
Typhus
Rocky mountain spotted fever

29. Septicemia: Lymphangitis
Bacteria actively multiplying and/or releasing toxins into blood
One symptom is lymphangitis - red streaks seen in skin radiating out from initial site of infection

30. Subacute Bacterial Endocarditis
Inflammation of endocardium, lining of epithelial cells in heart and valves
Subacute bacterial endocarditis
Occurs individuals with abnormal heart valve
Due usually to viridans group Streptococcus, follows dental work or primary infection elsewhere
Clots form, may break off to impair function of heart
Symptoms include fever, anemia, general weakness, heart murmur

31. Acute Bacterial Endocarditis
Individuals following a primary infection elsewhere
Characterized by rapid destruction of heart valves

32. Rheumatic Fever
Autoimmune complication of Streptococcus pyogenes pharyngitis
May lead to heart damage, arthritis, death

33. Tularemia Francisella tularensis
Also called rabbit fever, usually acquired by contact with infected rabbits
Local inflammation may lead to septicemia, pneumonia and abscesses throughout the body

34. Brucellosis Brucella species Also called undulent fever
A fever spike commonly occurs in evening
Most commonly transmitted by unpasteurized milk

35. Anthrax Bacillus anthracis Mainly disease of grazing animals
Through variety of portal of entry in humans (skin, respiratory, GI tract)
If through skin characteristic malignant pustules at site of entry
May progress to septicemia and death
Death usually due to toxin produced by organism

36. Plague: Bubonic/ Pneumonic
Yersinia pestis
Endemic in mountains in Southern California
Two forms of disease – bubonic plaque and pneumonic plague
Bubonic plague transmitted by rat fleas
MO gets into bloodstream, makes its way to regional lymph nodes which become painful and enlarged (called buboes)
Mortality rate in untreated cases is high
MO gets into lungs cause pneumonic plague, transmitted from person to person via droplet infection, higher mortality rate than bubonic plague (close to 100%)
Plague: Bubonic/ Pneumonic

37. Relapsing Fever Borrelia species Transmitted by ticks and lice
High fever, jaundice, and rose colored spots
Relapses occur because MO undergoes antigenic variation, each relapse less severe than preceding one

38. Lyme Disease Transmitted by ticks
Borrelia burgdorferi
Transmitted by ticks
Starts with characteristic rash at bite site, Erythema Chronicum Migrans (ECM), followed by flu-like symptoms
Years later, neurological and heart problems, arthritis may occur, probably due to an immune reaction to remaining MOs

39. Typhus Rickettsia prowazekii (epidemic) and Rickettsia typhi (endemic)
High, prolonged fever, stupor and small red spots
Transmitted by human lice (epidemic) and rat flea (endemic)

40. Rocky Mountain Spotted Fever
Rickettsia rickettsii
Transmitted by ticks
Symptoms include high fever, headache, rash over entire body

41. GI Tract Infections
Dental caries
Dysentery
Gastroenteritis

42. GI Tract Disease
Dental caries – bacteria (Streptococcus mutans) ferment sugar releasing acid that destroys enamel and dentin
Dysentery - severe diarrhea with blood and/or pus
Gastroenteritis - inflammation of stomach and intestinal mucosa

43. Gastroenteritis: Infection
Salmonella species, including Salmonella typhi which causes typhoid fever
Shigella species
Vibrio parahaemolyticus
Campylobacter jejuni
Certain strains of E. coli
MO attaches, invades, and multiplies.
A delay in symptoms as MO multiplies
Symptoms include fever, diarrhea (dysentery may occur), nausea, and possibly vomiting

44. Gastroenteritis: Intoxication
Staphylococcus aureus
Vibrio cholera
Certain strains of E. coli
Ingestion of preformed toxin, or toxin produced by MO which not invasive but multiplies at intestinal mucosa while liberating toxin
Symptoms DO NOT include fever, but may include abdominal cramps, watery diarrhea, nausea and vomiting

45. UTI and STD
Cystitis
Gonorrhea
Nongonococcal urethritis
Syphilis

46. Cystitis Most common cause is E. coli
Other G(-) enterics as well as G(+) bacteria may also cause infection
Inflammation of urinary bladder
Dysuria (difficult or painful urination) and pyuria (WBCs in urine)

47. Gonorrhea Neisseria gonorrhoeae
Usually transmitted by direct sexual contact
Commonly have concomitant Chlamydia trachomatis infection
Asymptomatic infections:
Males= 10%, Females= 20-75%
Carriers and transmit disease to others
Uncomplicated infections in males:
Acute urethritis, profuse purulent discharge filled  with GC; untreated may spread to cause  prostitis  and epididymitis

48. Gonorrhea Uncomplicated infections in females:
Vaginal discharge, burning or frequency of urination and menstrual  abnormalities
Complicated infections more frequently in women:
Spread  from  cervix  into fallopian tube
Pelvic inflammatory  disease  (PID) - endometritis,  salpingitis, peritonitis
Occurs in 10-20% of infected women
Symptoms include lower abdominal  pain, abnormal vaginal and cervical discharge, and  uterine tenderness
Can result in ectopic pregnancy and infertility.
Nongonococcal urethritis – Chlamydia trachomatis with symptoms as above

49. Syphilis: Primary
Treponema pallidum transmitted by direct sexual contact
Untreated disease occurs in several stages
Primary stage – penetration of skin or mucous membrane, characteristic painless hard chancre develops at site of entry
Chancre highly contagious and filled with MOs
MO enters lymphatics and disseminated
Chancre heals without treatment in few weeks due to local immunity, but MO has already disseminated

50. Syphilis: Secondary 4-8 weeks after primary stage
Lesions (filled with MOs) throughout body including skin, mucous membranes, organs, eyes
Most lesions on skin and mucous membranes
May also have loss of hair, mild fever, malaise
Also heals without treatment and patient may either spontaneously get well or develop latent infection

51. Syphilis: Tertiary
This stage characterized by granulomatous lesions (gummas) of skin, internal organs, CNS, bones, eyes, and cardiovascular system
By body’s hyperimmune reaction to remaining spirochetes