2. Haemophilus Spp (Blood-loving bacteria)
H. Influenzae
Does not cause influenza, Why named so?
mistakenly considered the cause of influenza 1890 Pandemic.
Gram negative coccobacilli
Obligate parasites of man
Cause hidden disease because:
Does not cause a specific disease
Responding first with antibiotics may mask Hib's
Difficult to isolate
Fastidious, require X (hemine) and V (NAD or NADP) factors
in chocolate agar
A "Rapid Assessment Tool" has been developed by WHO and CDC
to make sensible estimates of Hib
H. Ducreyi : STD (soft chancroid) not common
Opportunistic Haemophilus pathogens are rare
3. H. Influenza have no
specific syndrome but
can cause:
meningitis, conjunctivitis,
sinusitis, cellulitis, otitis,
epiglottitis, pneumonia,
Health Canada and www.cdc.gov/vaccines/pubs
4. One of the most transformable genomes
H. Influenza was the first free living organism to have the
complete genome sequenced in 1995
The genome consists of 1.8 MB of DNA in a single circular
chromosome of which 1.7 code for proteins.
How does it become highly-specific to humans?.
Mutations,Transformable by many ways,
Phase variation by DNA repeats
5. Diagnosis
Microscopy to detect in CSF, synovial fluids,
Culturing, difficult, may be not sensitive
latex particle agglutination test (LAT)
PCR
H.Influenza Gram stain H.Influenza Choclate agar
6. Treatment and prophylaxis
cefotaxime , ceftriaxone, ampicillin and sulbactam,
cephalosporins of the second and third generation, or
fluoroquinolones are preferred.
Hib conjugate vaccine
Hib is preventable, but there are two problems:
A shortage of information : difficult to diagnose, it
causes death without being recognized
Expensive: Hib vaccine is expensive
7. Vibrio
V. cholerae, and V. parahaemolyticus are human pathogens
V. cholerae: cause cholera. Comma shaped rods , with Two
circular chromosomes
What is Cholera? Cholera toxin activates adenyl cyclase causing
increased cAMP level and hypersecretion of fluids and electrolytes
Extensive watery diarrhea (15-20 liters/day) called Rice-Water Stool:
Colorless
Odorless
No protein
Speckled with mucus
Source contaminated waters and food
Caused 8 cholera pandemics, example of Pandemic strain is El
Tor
Treatment and prevention
Rehydration & supportive therapy
Water purification, sanitation & sewage treatment
Vaccines
8. Sack, David, et al. 2004. Seminar: Cholera. The Lancet. 363: 223-233.
9. Diagnosis
Rapid tests
Dark-field microscopy
Rapid immunoassays
Molecular methods – PCR & DNA probes
Selective/differential culture medium -
Thiosulfate Citrate Bile salts Sucrose (TCBS) agar
V. cholerae grow as yellow colonies
Biochemical and serological tests
10. Helicobacter
H. pylori = gastritis, peptic ulcer
disease(PUD)
Helical (spiral or curved) corkscrew shape and
lophotrichous (tuft at one pole)flagella helps in
penetration and colonization of mucosal lining of stomach
& duodenum
Acid-inhibitory protein
Hydrolyzes urea and inhibits acids in gastrics
• Most gastric cancers are preceded by an infection with
H. pylori
Microaerophilic: Change chape to coccoid when exposed to
oxygen or upon prolonged culture
11. Diagnostic aspects
Detected in endoscopic antral gastric biopsy material
Culture media containing whole or lysed blood
Microaerophilic
does not ferment or oxidize carbohydrates
Triple Chemotherapy (synergism):
Proton pump inhibitor (e.g., omeprazole = Prilosec(R))
One or more antibiotics (e.g., clarithromycin;
amoxicillin; metronidazole)
Bismuth compound
12. Mycobacterium tuberclosis: Tuberclosis 1/3RD of World has it, a
global Emergency.
TB what it is, and how it spreads?
Outside body Inside body:
Spreads through the air when a
person with TB: bacilli go to lungs and infect alveoli
Coughs Macrophages attack bacteria, but some
survive
Speaks Infected macrophages form tubercles
Dead cells form granulomas
Laughs
Sneezes
Sings
http://www.cpmc.columbia.edu/resources/tbcpp/abouttb.html.
13. Symptoms for Pulmonary TB:
There are many types of Tuberclosis, pulmonary
is most important
Perpetual Cough
Fever
Weight loss
Night sweats Types of TB bacteria include:
Mycobacterium tuberculosis
Loss of appetite
Mycobacterium leprae
Fatigue
Mycobacterium avium
Swollen glands
Chills
Pain while breathing
14. Some diagnostics
Acid fast staining, and Lowenstein-Jensen Agar
Skin test- Mantoux test
Purified Protein Derivative PPD injected in forearm and
examined 2-3 days later
Red welt around injection indicates infection
Examine medical history, x-rays, and sputum
15. Treatment and prevention
Take antibiotics for 6-12 months
Preventative drug to destroy dormant bacteria
For active TB, 4 medications: isoniazid, rifampin,
ethambutol, and pyrazinamide
Vaccines (relatively ineffective today)
Check with X-ray
17. Spirochetes:
Treponema, Borrelia, & Leptospira
Spirochete means “coiled hair” Greek. They are
tightly coiled like telephone cord, only a fraction of
a micron in diameter but hundred of microns long
Twisting Motility by periplasmic flagella (axial
fibrils or endoflagella) is a major difference
between this and other bacteria
18. Spirochaetes: Genus Treponema
Genus: Treponema: Treponema pallidum, causes syphilis
(sexually, or congenitally transmitted), delicate obligate parasite
Stages of Syphilis:
1. Primary Chancre lesion is the main sign
2. Secondary rash
3. Latent , no sign but bacteria present
4.Tertiary, very complicated systemic
Treponema pertenue, causes yaws
skin lesion
19. Spirochetes
Genus: Borrelia
Borrelia burgdorferi,
Causes a zoonotic vector borne disease called Lyme disease
Transmitted by ticks
Linear chromosome
Borrelia recurrentis, causes relapsing fever
Genus: Leptospira
Leptospira species, causes leptospirosis
Main Diagnostic tests for Spirochetes:
Darkfield microscopy
Fluorescent antibody staining
VDRL
Wasserman Test
Hemagglutination tests
20. Treatment and control
Penicillin remains drug of choice
• WHO monitors treatment recommendations
• 7-10 days continuously for early stage
• At least 21 days continuously beyond the early
stage
Prevention of Mother-child transfer by
barrier methods (e.g., condoms)
Prophylactic treatment of contacts identified
through epidemiological tracing
Cautiousness, and morals play significant
roles
21. Rickettsial Diseases
Transmitted by Arthropod Vectors
Fastidious, obligate intracellular bacteria that grow only on
cells, eggs, and tissue cultures
Transmitted by Arthropod Vectors
They are pleomorphic & coccobacillary
Do not show on Gram stain, but can be seen with either
Gimenez or Giemsa stains
Gimenez stain of tissue culture cells
infected with Rickettsia rickettsii
25. Pathogenesis and Clinical Symptoms
Pathogenesis for all these infections is very similar regardless
of species. A vasculitis (inflammation of blood vessel wall) is
caused by the invasion and multiplication of the organism in
the endothelial and smooth muscle cells of the blood vessels.
Clinical symtoms
Thrombosis, occlusion, and necrosis of blood vessel walls
Thrombocytopenia with hemorrhage
– occurs primarily as a result of platelet consumption as
opposed to true (DIC)disseminated intravascular coagulation
Massive capillary leakage, edema, hypotension, and
respiratory distress, encephalitis, myocarditis, & nephritis
26. Four Prototype Diseases
1. Rocky Mountain spotted fever… by Rickettsia rickettsii
Fever, heache, rash…
2. Murine typhus…by Rickettsia typhi
3. Epidemic typhus …by Rickettsia prowazekii
4. Q fever…by Coxiella burnetii
Occurs in veterinarians, ranchers, and animal researchers
from infected placenta of sheep, cattle, or goats (no
arthropod vector for C. burnetii). Pneumonia is common
27. Weil-Felix Reaction
and the bit of a history
Historical known that Proteus antibodis cross-reactive
with several of the rickettsiae. Today, Weil-Felix test is not
confirmed for rickettsial infection.
In Poland during World War II, two physicians cleverly
used killed Proteus bacteria to vaccinate the men of a
small town, to induce a positive Weil-Felix reaction.
The occupying Germans feared typhus epidemic and Due
the vaccination reaction, the village was saved of a certain
destruction. The men were not forced into the army, and
the women and children were not forced into the camps.
28. Diagnosis and treatment
Specific & sensitive tests:
Indirect immunofluorescent antibody (IFA)
Indirect hemagglutination antibody (IHA)
Complement fixation (CF)
Treatment
In life-threatening rickettsial infections, early antibiotic
intervention is recommended to prevent endothelial damage
Doxycycline, tetracycline, and chloramphenicol are the drugs
of choice
Prevention (transmitted by vectors so avoid them)
Use of repellents & protective clothing in endemic areas
Inspection & removal of ticks
Vaccine for RMSF is available for risk groups
Weekly doxycycline