Practice Exam 1 Qs Flashcards
What is the only genus of G- cocci that frequently cause disease?
Neisseria sp.
This bacteria is non motile, aerobic but can grow anaerobically, is positive for catalase and oxidase, and humans are the only reservoir.
Neisseria
This is Neissera sp. is nonencapsulated, with strong adhesions, please/antigenic variation, and found on the genitals?
N. Gonorrhoeae
True or false. Minigitidis is encapsulated with endotoxins and hemolysins.
True
How are gonococci internalized?
Parasite directed endocytosis
True or false. Gonococci utilize glucose, but not sucrose or maltose?
True
True or false meningococci utilizes both glucose and maltose
True
Why are vaccines to gonococci difficult to produce?
Due to antigenic phase variation they change too often due to this strong virulence factor, there IS a vaccine to meningococci however.
I am a small, aerobic, gram - coccobacilli which colonizes the upper respiratory tract of almost all humans, is non type able, non encapsulated.
Haemophillus influenza
Which influenza is most virulent?
Hib - H. Influenza type b (causes bacteremia and meningitis in children less than 2, facial cellulitis, epilottitis, bronchitis, pneumonia
What does H. Influenza need for growth and why?
Lysed blood chocolate agar - requires hemin (x factor) and NAD+ (v factor) for growth
I am a gram - bacilli, motile, found in soil/water/soap/lotion, cause swimmers ear and hot tub rash.
Pseudomonas aeruginosa
All other strains EXCEPT haemophilus only require what for growth?
ONLY NAD+ Blood agar - not chocolate agar
Where does pseudomonas aeruginosa get its carbon and nitrogen from?
Acetate and ammonia, readily available in most environments (easy requirements)
Mucoid polysaccharide capsule, siderophores, elastase, exotoxin a, phospholipase c are all ________ types of virulence factors in psudomonas?
Persistence virulence factors (collagenase, flagella and heat stable hemolysins are all part of dissemination (spread) virulence factors).
True or false, pseudomonas generally adheres well to healthy epithelium?
False - they are opportunistic and take advantage of cuts and immunosuppresed/compromised hosts
What is the endotoxin in pseudomonas?
LPS - which interacts with TLR4 to initiate host inflammatory response - fever hypotension, gram - sepsis
What cleaves elastin and collagen to cause direct tissue damage, cleaves proteinase inhibitors and cleaves complement and immunoglobulins?
Elastase - multifunctional protease (elastase cleaves elastin - similar names)
When cystic fibrosis respiratory cells bind more P. Aeruginosa, why does this happen and what are the results?
Cystic fibrosis transmembrane conductance regulator (CFTR) gene is dysfunctional due to genetic mutation causing 1. The loss of Cl - transport, 2. Dehydration of respiratory secretions resulting in thick mucous. Basically there is a gene for CF and peoples lungs fill with mucous.
What is characterized by severe systemic illness due to organ malfunction?
Sepsis, this is NOT the same as bacteremia
How does pseudomonas D.C. abuse sepsis?
Due to microbial products interacting with host lymphatic cells
What is the best method of treating pseudomonas?
Antibiotic synergism
What are populations or communities of micro organisms adhering to a surface?
Biofilm
What is the true phenotype of most bacteria?
Encased in extra cellular glycoproteins and polysaccharide (glycocalyx)
Which bacteria are important in biofilms and quorum sensing?
P. Aeruginosa
I am strictly anaerobic, gram positive rod, produces endospores, are resistant to heat, radiation, drying and most disinfectants.
Clostridium
I am the leading cause of nosocomial diarrhea, tough to culture, most antibiotics kills the normal flora before me causing pseudomembranous colitis
C. Difficile
I cause cellulitis, gas gangrene, food poisoning. My spore germinate without oxygen, comporomised blood flow, calcium ions and the availability of peptides and amino acids.
C. Perfringens
How do you treat C. Perfringens?
Surgically excise infected muscle, antibiotics, horse antitoxins, high 02 and reestablish blood supply
I have heat resistant spores that can survive food processing, neurotoxins, and I prevent the release of acetylcholine causing flaccid paralysis
C. Botulinum
How do you treat c. Botulinum?
Trivalent antitoxin from horses
What ar the three types of botulism?
Food borne, wound, and infant
I am famous for being found everywhere within your GI tract, but infections follow a traumatic injury - I cause lockjaw and can be treated with DPT vaccine
C. Tetani - tetanus
I am responsible for the symptoms of tetanus by inhibiting GABA release causing reflex spasms and spastic paralysis
Tetanospasmin
What NT is blocked by botulism? What about tetanus?
ACH acetylcholine, GABA (this is the “yoga” NT because it helps muscles relax)
I am a small gram - bacteria with no peptidoglycan (Murien) in my cell wall. I grow intracellularly because I NEED energy (ATP) from my host
Chlamidiae
I am the most common STD and leading cause of blindness in the world from inflammation in the conjunctiva which can cause blindness and scaring of the cornea
Chlamydia trachomatis
HOw is chlamydia trachomatis internalized?
Receptor mediated endocytosis
Which type of chlamydia species has every living adult had?
Chlamydophila pneumonia - “walking pneumonia”
I am a small gram - rod, obligate intracellular bacteria that can synthesize my own ATP unlike chlamydia and I can spread to humans by ticks/lice/rats
Rickettsiae
How does Rickettsiae enter and spread?
Enters via infected tick bite, specific to endothelial skin cells to induce endocytosis, causes losing of the phagosome and it replicates in the cytoplasm
What causes the rash/hemorraghic spots from Rickettsiae infections?
Lysis of cells results in the leakage of blood - hemorrhage
I’m transmitted by the Lone Star tick and specific for leukocytes. I infect mostly monocytes and macrophages and will cause fever, malaise, headache, and myalgia. I develop within host cell vacuoles first as reticulate cells then as dense core cells within cytoplasmic endosomal vacuole (morula).
Erlichia
I’m the smaller organism capable of growth on a cell free media, I must have cholesterol, I lack a cell wall (no murein) so PCN does not work against me.
Mycoplasma
What is the prototype mycoplasma that causes walking pneumonia in which penicillin does not clear it
M. Pneumonia
What immunoglobulin is used for diagnosis and txt of mycoplasma
IgM
Are tattoos-Amina and botulinum toxins endo or exotoxins?
Exotoxins because they release their toxin out of their cells into the host
I am a common vaginal flagellate spread by sexual contact causing vaginitis
Trichomonas vaginalis
An analysis of the small intestines revealed copious amounts of watery stool without blood or leukocytes, and no tissue damage. What are the likely toxin producing bacterial pathogens?
Vibrio enterotoxigenic e. Cold (ETEC)
A stool analysis from the large intestines show small volume of bloody stool with leukocytes and tissue ulceration - what am I?
Salmonella or Shigella
What antigen distinguishes between shigella spp
O antigen
What does shigella invade via invasion plasmid antigens
M cells - epithelial cell that recognizes different hormones, usually let anything inside (their major fallback)
How is shigella dystenteriae type 1 different?
It produces shiva toxin and presents as an invasive diarrhea
What are 2 common salmonella poisoning results
Gastroenteritis or typhoid fever
What does a low pH do for salmonella?
Induces expression of 40 proteins found on pathogenicity islands on large virulence plasmids
What causes diarrhea in enteropathogenic E. coli?
Malabsporbtion due to microvilli disruptions and disruption of epthielial tight junctions, NOT from toxin production
What is the most common form of bacterial infection of an organ system?
UTI - increases risk with older age
This UTI is characterized by all normal defense mechanisms intact, no recent hospital visits and the disease is limited to the lower urinary tract?
Uncomplicated UTI - normal every day factors are the cause
Complicated UT is the opposite, usually nosocomial and usually means the infection has spread to the kidneys - pyelonephritis
True or false - uropathogenic E. coli are common causes of uncomplicated UTIs
True
What is the common infection from Klebsiella?
Bacterial pneumonia
Which type of pili is important for respiratory tract epithelial cells in klebsiella?
Type 3 pili - type 1 is for urinary
I am very prevalent in gram - bacterium in the GI tract I am slow an cause gastritis and peptic ulcers. I am readily killed by gastric acid and I produce urease and cytotoxins to downregulate somatostatin-producing cells?
Helicobacter pylori
Gonorrhea is commonly asypmtomatic in men or women?
Women
Which bacteria causes trachoma which may lead to blindness?
Chlamydia trachomatis
Gas gangrene occur as a result of infection of what bacteria
C. Perfringens
True or false, N. gonorrhoeae is an obligate human pathogen
True
Before bacteria can grow and divide to form a biofilm, what must first occur
They must irreversibly attach to a surface
N. Gonococci and B. Pertussis can cause death of ciliated cells. What is unique about the way in which they do this?
Death of the ciliated cells is caused by a fragment of peptidoglycan
What is the process by which elementary bodies (EB) are internalized?
Receptor-mediated endocytosis
Once inside the cells, what do elementary bodies differentiate in to?
Reticulate bodies (RB)
What organisms do this cycle of EB to RB?
Chlamidiae
Which cells do R. ricketsii invade?
Vascular endothelial cells, and spread through the blood and cause hemorrhage
Which genus of bacteria contains the most common agents of sexually transmitted bacterial infections?
Chlamydiae
What is unusual about the cell wall of Chlamydiae
It does not contain peptidoglycan (gram nobody, LOL)
What is unusual about the cell wall of mycoplasma?
It doesn’t have one! NO CELL WALL
What are the two types of bacterial cells that may be visible in the morula or Erlichia?
Dense core cells and reticulate cells
What are two ways in which EB modify the endocytic vehicle?
Maintain pH above 6.2, prevent fusion with the lysosomes
What is the most prevalent Chlamydiae pathogen in the human population
Chlamydophila pneumonia
Why is penicillin ineffective for treatment of Chlamydial infections?
They are intracelluar - the penicillin cannot penetrate all the membranes
What are two types of cells commonly infected by ehrlichia?
Monocytes and macrophages and neutrophils
What is the infection cell type of Chlamydiae that survive outside the hosts cells
Elementary bodies - reticulate bodies are inside the vesicles
To grow the mycoplasma, what must be added in their medium?
Sterols (cholesterol)
Infected humans are the only known reservoir for which pneumonia pathogen?
Rikettsiae
What are cold hemaggluttinins?
IgM which causes RBCs to stick together at low temperatures, aggregate, association with M. Pneumoniae
How do rickettsial RBs propel themselves?
Actin polymerization within host cells - comet tails
Bronchiopneumonia is caused by?
Mycoplasma pneumoniae
What contains genes for enzymes and antibiotic resistance?
Plamids
What is the most important structure related to microbial attachment to cells?
Glycocalyx
True or false, endotoxins are secreted from cells
False
What types of agar do you grow h. Influenzae on ?
Chocolate agar
Treponema pallidum causes?
Syphillis
Borrelia burgdorferi causes?
Lyme disease
