1. Miscellaneous Bacterial Agents of Disease
Chapter 21

2. spirochetes Gram negative human pathogens Treponema Leptospira
Borrella

3. Treponema thin, coiled cells
live in the oral cavity, intestinal tract, & perigenital regions of humans & animals
Pathogenic species are strict parasites

4. Treponema pallidum human is the natural host
extremely fastidious & sensitive, cannot survive long outside of the host
causes syphilis
Primary syphilis: chancre lesion
Secondary syphilis: spread throughout the body via blood stream
Latent syphilis: obvious symptoms disappear
Tertiary syphilis: Hyperimmune response that can affect many systems. (dementia, blindness, heart disease etc. etc.)
Congenital syphilis: infection across the placenta-nasal discharge, skin eruptions, bone deformation, nervous system abnormalities
treatment: penicillin G

5. Chancre

6. Darkfield Microscopy

7. Leptospira
tight, regular individual coils with a bend or hook at one or both ends
L. interrogans – causes leptospirosis, a zoonosis
bacteria shed in urine; infection occurs by contact; targets kidneys, liver, brain, eyes
sudden high fever, chills, headache, muscle aches, conjunctivitis, & vomiting
50-60 cases a year in US

8. Borrelia large, 3-10 coils Borrelioses transmitted by arthropod vector
B. hermsii – tick-borne relapsing fever
There also a louse-borne relapsing fever (B. recurrentis)
B. burgdorferi - Lyme disease

9. B. hermsii - relapsing fever
mammalian reservoirs –squirrels, chipmunks, wild rodents
tick-borne
after 2-15-day incubation, patients have high fever, shaking, chills, headache, & fatigue
nausea vomiting, muscle aches, abdominal pain; extensive damage to liver, spleen, heart, kidneys, & cranial nerves
parasite changes & immune system tries to control it- recurrent relapses
tetracycline

11. B. burgdorferi - Lyme disease
transmitted by ticks
complex 2-year cycle involving mice & deer
nonfatal, slowly progressive syndrome that mimics neuromuscular & rheumatoid conditions
70% ? get bull’s eye rash
fever, headache, stiff neck, & dizziness
if untreated can progress to cardiac & neurological symptoms, polyarthritis
tetracycline, amoxicillin
vaccine for dogs, human vaccine discontinued
Prevention-insect repellant containing DEET

12. Lyme Disease

14. Lyme disease

15. Vibrio cholera comma-shaped
One of top 7 causes of morbidity & mortality
ingested with food or water
infects surface of small intestine, noninvasive
cholera toxin causes electrolyte & water loss through secretory diarrhea (“rice-water” stool), resulting dehydration leads to muscle, circulatory, & neurological symptoms
treatment: oral rehydration, tetracycline

16. Cholera in Haiti
1,186 dead from cholera, 19,646 hospitalized (as of November 20th, 2010)

17. Action of Cholera Toxin
Figure 21.25

18. other Vibrio
salt-tolerant inhabitants of coastal waters, associate with marine invertebrates
Vibrio parahaemolyticus –gastroenteritis from raw seafood
Vibrio vulnificus
gastroenteritis from raw oysters
nasty skin/tissue infections of cuts and scratches

19. Campylobacter jejuni important cause of bacterial gastroenteritis
transmitted by beverages & food (poultry most common)
reach mucosa at the last segment of small intestine near colon; adhere, burrow through mucus and multiply
symptoms of headache, fever, abdominal pain, bloody or watery diarrhea that is self-limiting
heat-labile enterotoxin

20. Campylobacter jejuni

21. Helicobacter pylori
Curved cells discovered in 1979 in stomach biopsied specimens
Slightly helical, highly motile bacterium that colonizes the stomach of its hosts
Causes gastritis and most (if not all) peptic ulcers. (Also a big risk factor for stomach cancer)

22. H. pylori and Peptic Ulcers
Figure

23. H. pylori and Peptic Ulcers
Figure

24. H. pylori and Peptic Ulcers
Figure

25. Diagnosis, Treatment, and Prevention
Presence of H. pylori can be demonstrated by a positive urease test
Biochemical tests provide a definitive identification
Treatment
Antimicrobial drugs are used in combination with drugs that inhibit acid production
Prevention
Prevention involves good hygiene, adequate sewage treatment, water purification, and proper food handling

26. Rickettsia obligate intracellular parasites gram-negative cell wall
among the smallest bacteria
nonmotile pleomorphic rods or coccobacilli
ticks, fleas & louse are involved in their life cycle
bacteria enter endothelial cells & cause necrosis of the vascular lining – vasculitis, vascular leakage & thrombosis
treat with tetracycline & chloramphenicol

27. Types of rickettsioses
epidemic typhus – R. prowazekii carried by lice; starts with a high fever, chills, headache, rash; May have a chronic, recurrent form
endemic typhus (murine typhus) – R. typhi, harbored by mice & rats; occurs sporadically in areas of high flea infestation; milder symptoms
Rocky Mountain spotted fever – R. rickettsii zoonosis carried by dog & wood ticks; most cases on eastern seaboard; distinct spotted rash; may damage heart & CNS
Ehrlichia genus: human monocytic ehrlichiosis
Anaplasma genus: anaplasmosis

28. Rocky Mountain Spotted Fever

29. Rocky Mountain Spotted Fever Rickettsia rickettsii

30. Coxiella burnetti causes Q fever intracellular parasite
produces an unusual resistant spore
harbored by a wide assortment of vertebrates & arthropods
transmitted by air, dust, unpasteurized milk, ticks
usually inhaled causing pneumonitis, fever, hepatitis
tetracycline treatment
vaccine available

31. Coxiella burnetti

32. Bartonella small gram-negative, fastidious, cultured on blood agar
Bartonella-caused diseases
trench fever, spread by lice
cat-scratch disease, a lymphatic infection associated with a clawing injury by cats.
Organism carried by 40% of cats
Most infections localized and resolve a a couple weeks
bacillary angiomatosus in AIDS patients
tetracycline, erythromycin & rifampin

33. Cat-scratch disease
Bartonella henselae

34. Chlamydia obligate intracellular parasites
small gram-negative cell wall
C. pneumoniae – causes an atypical pneumonia that is serious in asthma patients
C. psittaci – causes ornithosis, a zoonosis transmitted to humans from bird vectors; highly communicable among all birds; pneumonia or flulike infection with fever, lung congestion

35. Chlamydia trachomatis
human reservoir
2 strains
trachoma strain– attacks the mucous membranes of the eyes, genitourinary tract & lungs
ocular trachoma – uncommon in U.S. but common in Africa and Asia. Severe infection, deforms eyelid & cornea, may cause blindness
inclusion conjunctivitis – occurs as babies pass through birth canal; prevented by prophylaxis
STD – urethritis, cervicitis, salpingitis (PID),infertility, scarring
lymphogranuloma venereum strain– disfiguring disease of the external genitalia & pelvic lymphatics

36. Chlamydia trachomatis
Lymphogranuloma venereum lesion
Trachoma

37. Mycoplasma naturally lack cell walls, highly pleomorphic
treated with tetracycline, erthyromycin
M. pneumoniae – primary atypical pneumonia; pathogen slowly spreads over interior respiratory surfaces, causing fever, chest pain & sore throat.
M. hominis & Ureplasma urealyticum – weak sexually transmitted pathogens

38. Bacteria in dental disease
oral cavity is a complex, dynamic ecosystem, containing 400 species
dental caries – slow progressive infection of irregular areas of enamel surface
begins with colonization by slime-forming species of Streptococcus & cross adherence with Actinomyces
process forms layer of thick, adherent material (plaque) that harbors masses of bacteria which produce acid that dissolves enamel
If plaque is allowed to stay, secondary invaders appear – Lactobacillus, Bacteroides, Fusobacterium, Porphyromonas, Treponema.
Acid dissolves tooth enamel

40. Thin mucous coating of salivary proteins
Streptococcus mutans
Secondary invaders

41. Peridontal disease soft tissue disease
when plaque becomes calcified into calculus above and below the gingiva
this irritates tender gingiva causing inflammation – gingivitis
pockets between tooth & gingiva are invaded by bacteria (spirochetes & gram-negative bacilli)
tooth socket may be involved (peridontitis)
tooth may be lost