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Flashcards in Final; Small Gram-Negative Pathogens Deck (48):

This is an obligate intracellular pathogen growing only inside cells or on live tissues and depend on their host for ATP



What are the 4 recognized species of Chlamydiae

C. trachomatis
C. pneumoniae
C. psittaci
C. pecorum


Chlamydiae is the leading cause of preventable what and the most common what

agents of sexually transmitted bacteria infections


How is Chlamydiae spread

droplet or direct infection
4 F's; fingers, flies, fomites, fornication


Where does Chlamydiae infect

mucosal epithelial cells
localized; eyes, lungs, genitalia


What are the symptoms of a Chlamydiae genital tract infection

males; prostitis, epididymitis
femalse; cervicitis, PID, premature birthda, pelvic pain, newborn infection
both; urethritis, infertility, proctitis, arthritis


How is the disease manifested in females

usually asymptomatic in females; chronic or repeat infections can cause sterility and/or ectopic pregnancy


What is characteristic of Chlamydiae infections

may be acute or chronic; silent period
asymptomatic carriage results in most damage and scarring
during birth, infants can contract the infection


This is the non-replicating infectious particle that enters epithelial cells and is internalized by receptor-mediated endocytosis

elementary body


The elementary body modifies the endocytic vesicle in which two ways

maintain pH above 6.2
prevents vesicle from fusion with lysosomes


How is the vesicle modified by the host

modified with host glycolipids for camouflage


What do the infectious EBs change into

larger intracellular active organisms called reticular bodies


What do reticular bodies do within the vesicle

synthesize molecules using host metabolites and energy
divide by binary fission
organisms develop slowly (2-3 days per cycle)


How do reticular bodies uptake nutrients

tube-like structures that allow them to feed on eukaryotic host cell without leaving the inclusion vacuole
18-23 tubes


This is inflammation of the conjunctiva, can cause blindness and scarring of the cornea

trachoma (C. trachomitis)


How is trachoma spread

by direct contact with yes, nose, and throat secretions from affected individuals or contact with objects such as towels or washcloths


This is a STD, systemic invasive infection apparent in the lymph nodes that drain the genital tract found in developing countries

lymphogranuloma venerum


This is the most prevalent chlamydial pathogen in the human population; 50% of people up to age 20% are infected and 80% of older adults

chlamydophila pneumoniae


C. pneumoniae invokes what type of symptoms

asymptomatic or acute respiratory response but chronic respiratory infections have been associated with asthma, CF, and lunch cancer
directly observed in 40-100% of patients with atherosclerotic heart lesions


What is the treatment for chlamydia

target the metabolically active RBs
there are four membrane laters to penetrate
organisms grow slow so the antibiotics must be taken for a longer period of time


This is an obligate intracellular small gram-negative rod bacterium that can be spread from animals to humans (zoonoses)



What is the main difference between rickettsiae and chlamydia

rickettsiae can synthesize its own ATP and is capable of independent metabolism
it may lack certain metabolites necessary for growth
no flagella or endospores
must be cultivated in animals, embryonated eggs, or cell cultures in the lab


What are some diseases caused by rickettsiae

rocky mountain spotted fever


How is rickettsiae transmitted

only ticks are naturally infected
the ticks feed on large mammals and the larva/nymph feed on small rodents
the bacteria is spread through the blood stream


How does rickettsiae spread and multiply

attaches to vascular endothelial cells; induces endocytosis
once inside, presumably lyse the phagosome (phospholipase) and enter the cytosol


How does R. prowazekii exit the cell



How does R. ricketttsii exit the cell

gets extruded from the cell through local projections (filopodia)
actin helps to give it a push


How does R. tsutsugamushi exit the cell

by budding through the cell membrane; will remain enveloped as it infects other cells


What is the injury to the host as a result of Rickettsiae

it is proportional to the number of intracellular bacteria
lysis of cells leads to rash; hemorrhagic spots
it can travel to other vessels including heart and brain
75% of patients will clear before antimicrobial treatment


This causes typhus fever, recrudescent typhus, and is transmitted by human lice
the reservoir is humans and flying squirrels

R. prowazekii


This is prevalent and widespread, marine typhus, and is transmitted by rats and rat fleas

R. typhii


This causes scrub typhus, there is a variety of antigenic types but there is no rash as observed in the other

Orentia tsutsugamushi


This is an obligate intracellular bacteria discovered in 1987 that infects mostly monocytes, macrophages, and neutrophils



What are the disease/infections of ehrlichia

human granulocytic ehrlichiosis
human monocytic ehrlichiosis
causes fevers, malaise, headache, and myalgia


Where does ehrlichia develop within the cells

within host cell vacuoles first as reticulate cells (RC) and then as dense-core cells (DC)


Why is diagnosing rickettsiae problematic

during the fist visit patients may not be aware of tick bite or have a fever/rash
required eukaryotic cell cultures or inoculation of animals
handling is hazardous


What are the clinical diagnosis tests for rickettsiae

antibody titer
fluorescent antibody assay
complement fixation
latex agglutination


This is the smallest organism capable of growth on cell-free media, its cells membranes contain sterols and is found in



What are some important characteristics of mycoplasma

*requires sterol
characteristic "friend egg" appearance
small colonies
slow growth
lack of cell wall; not sensitive to penicillin


What are the four species of mycoplasma that causes disease

M. pneumoniae
M. genitalium
M. hominis
Ureaplasma urealyticum
some microplasms are part of microbiota


Where is M. pneumonia encountered

humans are the only reservoir
spread through close contact via respiratory droplets; mild to moderately contagious
is adheres to respiratory epithelium


M. pneumoniae is typicaly referred to as what

"walking pneumonia" primary atypical pneumonia; not cleared by penicillin


Where does M. pneumonia infect

colliery function of the lungs is impaired
it is largely limited to the respiratory mucosa that lines the airways
doesn't get into lung alveoli; bronchopneumonia
tissue toxin substances may include H2O2


What are the main cells of the inflammatory response



What type of damage can M. pneumonia cause besides in the respiratory tract

hemolytic anemia; IgM = cold hemagglutinins, colder temps cause them to aggregate
erythema multiforme (rash)


This is the newest emerging human pathogen causing urethritis, cervicitis, endometritis, and PID

M. genitalium


These are frequently associated with diseases in newborns, commonly found in respiratory and genitourinary tract; and is present in most of the sexually active population

M. hominis and U. urealyticum


True or False
M. hominis and U. urealyticum can be isolated from the spinal fluid of newborns, but always cause disease

False; it doesn't always cause disease