Lecture #21 Flashcards
Filamentous Hemagglutin
Aids in attachment and prevents phagocytes from responding to infection
Pertussis Toxin
Aids in attachment and causes increased mucus production
Tracheal Cytotoxin
Inhibits the movement of cilia on ciliated respiratory cells
Symptoms of Pertussis
Vomiting after cough, subjunctival hemorrhages, rib fractures, incontinence, hernias, facial hematomas
Treatment of Pertussis
Manage signs and symptoms
Antibacterial drugs have little effect (unless given early)
Prevention of Pertussis
Immunization with the DTaP vaccine
Cases in the US are increasing due to a refusal by some parents to have their children immunized
Pseudomonas aeruginosa
Gram- negative, rod, motile, aerobic
Can live in any moist environment
Capable of growing in distiller water
From the Greek: pseudes “false” and monas “single unit”
NOT part of a human’s normal microbiota
Pseudomonas aeruginosa Disease
Can colonize almost any organ or tissue
Results in various diseases
Opportunistic pathogen of immunocomprised patients, burn patients, and cystic fibrosis patients
Attachment to human cells via
Capsule (shields from phagocytosis)
Numerous Fimbrae
Adhesins
Numerous toxins inhibit protein synthesis in eukaryotic cells
Diagnosis of Pseudomonas aeruginosa
Catalase positive
Beta-hemolytic on blood agar
Produces PYOCYANIN
green in color
Grape-like odor
Treatment of Pseudomonas aeruginosa
Resistant to many antibiotics
Quinolone antibiotics still seem to be effective
Prevention of Pseudomonas aeruginosa
Maintain a sanitary environment
Hand washing
Vibrio (genus)
Gram-negative, motile, oxidase positive, curved rods
All species are SALT-TOLERANT
Vibrio cholera
Most common species to infect humans
Humans become infected with V. cholera by ingesting contaminated food or water
Found most often in communities with poor sewage and water treatment
Some V. cholera infections are asymptomatic or cause only mild diarrhea
Cholera
Severe abrupt watery diarrhea and vomiting
RICE-WATER STOOL is a characteristic
Results in severe fluid and electrolyte loss
Can progress to coma or death
Strain O1 EI Tor is very virulent and widespread
Cholera toxin
Composed of two subunits: A and B
B binds to epithelial cells
A is cleaved and a small portion (A1) enters the cell
Cholera Diagnosis
Usually based on the characteristic rice-water stool
Isolate the organism from stool samples
Treatment of Cholera
Fluid and electrolyte replacement
Antimicrobial drugs are not effective because they are lost in the watery stool
Chlamydia (genus)
Do not have cell walls
Have two membranes but without any
peptidoglycan between them
Grow and multiply only within the phagosome of host cells (OBLIGATE INTRACELLULAR PARASITE)
Have a unique developmental cycle involving 2 forms
Both forms can occur within the
phagosomes of a host cell
Bordetella pertussis
Gram-negative, non-motile, short rods, aerobic
Humans are the only known host
Causes the disease PERTUSSIS (whooping cough)
Chlamydia trachomatis
Only two known hosts
One strain infects mice
All others infect humans
Infect the conjunctiva and various mucous membranes
Enters the body through abrasions and lacerations
Two clinically relevant strain types
TRACHOMA strains
LGV strains
Trachoma
Bacteria multiply in conjunctival cells resulting in scarring
Scarring causes eyelashes to turn inward and abrade the eye
Infects children at birth
Transmitted by flies
Endemic in crowded, poor communities with poor hygiene and inadequate sanitation
500 million cases worldwide
8 million visually impaired individuals
Treatment of chlamydia Trachoma
Prompt treatment with antibiotics and surgical correction of the eyelid deformities
Prevention of reinfection (hygiene)
Chlamydia (LGV)
Caused by trachomatis LGV strain
The most common STD in the U.S
Can infect children at birth
-Initially a small, painless lesions around the
genitals
-Painful urination/intercourse discharges,
inflammation
-Easily spread to the eyes
LYMPHOGRANULOMA VENEREUM- may progress to the lymph nodes in the groin producing swollen, painful buboes
1-4 million new cases each year in the US
More common in 3rd world countries
90 million new cases each year
Treatment of chlamydia (LGV)
Antibiotics are effective
