Microbiology Exam 4 -- Important Pathogens & Public Health

Is there a treatment for CWD?

No treatment

Describe how EHEC is diagnosed and treated.

Subsides by itself, supportive care. Antibiotics are bad because an overload of shiga toxin would be released.

Describe the pathogenesis of Staphylococcus aureus.

*Deadly cocktail of surface molecules & toxins* --surface proteins promote colonization of host issues --leukocidins kill WBCs and allows expansion --protein A binds the heavy chain of antibody function as opsonins --secretes large collection of enzymes and toxins --overstimulation of T-cells

Describe the reticulate form of Chlamydia.

*Large replicative form* --begins genome replication, growth and division --100 organisms then 1) back to elementary, lyse cell and find other host cells 2) adopt a non-infectious, non-replicating persistent form to replicate later

How is Clostridia difficile treated?

*Metronidazole or Vancomycin (serious) *Colectomy *Fecal bacteriotherapy

Describe the microbe features of Chlamydia.

*Number One Infectious Disease* --obligate intracellular parasites of eukaryotes --no cell wall peptidoglycan --extremely temp sensitive --grows inside cell --2 forms: elementary & reticulate

Describe the disease features of the Rhinovirus.

*One of the most successful pathogens of humans* --infection of nose --common cold --symptoms of nasal discharge & headache (2-3 days after infection) --abates in 9 days

Describe the elementary form of Chlamydia.

*Small transmissible form* --metabolically inert --adhesins on outer surface --stick to host and taken up --inside vesicles and interferes with lysosome fusion and acidification --activates modify vesicle and prevents fusion --differentiates into reticulate body

How is Staphylococcus aureus treated?

*Treated w/antibiotics *Many strains resistant, especially MRSA *if resistant, Vancomycin

What are the clinical manifestations of Staphylococcus aureus?

*Wide range of pus-forming infections* --swelling --fever --pus --deep seated tissue infections of bone and heart --vomiting if food-borne illness

What is Chronic Wasting disease and its features?

--Contagious protein is PrPc, which is ingested from excrement --Spreads throughout body by 16 months through lymph system (tonsils), brain --Not in humans

Describe the microbe features of the papillomavirus.

--DS circular DNA genome about 8 kb --not enveloped, have icosahedral capsid

How is malaria traeted?

--Paraquine (effective against liver stage) --Chloroquine (effective against blood stage) --IV cocktails

Describe some symptoms of Chlamydia.

--can be asymptomatic --painful urination, lower abdominal pain and discharge from penis and vagina

Describe some complications of Chlamydia.

--can cause pelvic inflammatory disease in women --> causes sterility --eye infections, respiratory disease, joint infections

Explain why overuse of antibiotics is a problem and what can be done to mitigate it.

--development of new drugs --prudent antibiotic us --surveillance --infection prevention --infection control by other methods

Describe how Shiga toxin works.

--encoded on lambdoid phages that are lysogenic and can integrate into E Coli genome --builds up in E Coli cell --> die --> cell releases toxin --AB toxin/exotoxin --A subunit enters cell after Shiga toxin binds to receptor then it cleaves rRNa and kills cells

What are the clinical manifestations of Influenza?

--fever --malaise --headache --body ache --nasal discharge --coughing --sore throat --fatigue

Describe the clinical manifestations of papillomavirus.

--forms papillomas or warts --itching/discomfort/pain

Describe the clinical manifestations of malaria.

--general malaise --fever/sweats --anemia --disruption of kidney function --hematuria (blood in urine) --lowering of blood pressure --interference with clotting/coagulation factors

Describe the general characteristics of Clostridia difficile.

--gram positive --strict anaerobe --obligate fermenters --spore formers (most) --able to survive adverse conditions in environment-spores --rapid growth --produces several types of toxins

Describe the microbe features of Staphylococcus aureus.

--gram positive cocci --catalse positive --common inhabitant of the skin --ferments sugar to lactic acid products --perform oxidative phosphorylation when oxygen is present --salt tolerant

Describe the pathogenesis of the Rhinovirus.

--gram positive ssRNA virs --enters cell via iCAM receptor --virus released once the cell lyses --small and mroe efficient genome

Describe the Toxin Shock Syndrome toxin.

--hydrophobicity of protein gives its ability to cross mucosal surface --produced during a stationary phase --TSST is located on a pathogenicity island that is flanked by mobile genetic elements

How is the common cold treated?

--let it pass -reduces symptoms w/over the counter meds --vitamin C not cure --vaccinate not possible

What are some clinical manifestations of Clostridia difficile?

--part of normal flora in some healthy people --often acquired after hospitalization or antibiotic use *Manifests as mild-severe diarrhea, bloating, and abdominal pain*

Describe the pathogenesis of Influenza.

--transmitted by airborne droplets --drops in pH is a signal for virus to enter nucleus --performs copy & cap stealing --replication mode then virus buds out

How does Clostridia difficile infect the cell?

--two toxins A and B *tcdA and tcdB --have two domains (AB) --damages cells by inactivating Ras and Rho GTPase *cell signaling molecules *cell rounding *apoptosis

Describe the pathogenesis of EHEC.

--use adhesion on their fimbriae to attach --tight binding to small intestine, forming pedastals --type III secretion system using shiga toxin, which cleaves rRNA and kills cells

How is the HPV prevented?

--vaccine an incredible success --pap smear used to diagnose aberrant cells

What are some symptoms of Chronic Wasting disease?

--weight loss --isolation from herd --loss of coordination --hypersalivation --frequent urination --excessive thirst

How does a vaccine work?

1) Live attenuated-microbe has reduced virulence but still is capable of replication --> development of cell-mediated immunity 2) Dead virus or bacteria --> more doses for cell mediated immunity to be effective 3) Protein subunits 4) Polysaccharides 5) Toxins

What are 3 general classes of vaccines and give examples of each type?

1) Live attenuated-microbe with reduced virulence but still capable of replication (mumps, measles, TB) 2) Dead virus of bacteria (polio, rabies, cholera) 3) Other (Hepatitis B, anthrax, tetanus)

Describe the pathogenesisis of Plasmodium, malaria.

1) Liver Stage (may divide for a while, then go dormant for awhile) 2) Blood Stage (stick to RBCs, begin to feed on RBCs, causes RBC to lyse, when many lyse at once = crisis)

Describe the pathogenesis of Chlamydia.

1) infects the epithelial cells of the cervix 2) bacteria travel up the endometrium into the fallopian tubes 3) the neutrophils inflammatory response 4) adaptive response in submucosa sigA - secretory IgA pigA - polymeric IgA 5) scarring and occlusion

What are four ways that microbes become resistant to microbes?

1) reduce permeability of cell to antibiotic 2) inactivation of antibiotic 3) alteration of target 4) efflux of antibiotic out of cell via efflux pumps

Describe the microbe features of Plasmodium, which causes malaria.

Difference in species is related to the differences in preference for age of red blood cells. *Parasitic protozoa*

What are some complications of Clostridia difficile?

Fever, Leukocytosis, Pseudo-membranous colitis, Toxic megacolon, Sepsis shock, Death

Describe the disease features of E. Coli EHEC.

Gram negative, enterohemorrhagic E. Coli in which fimbriae allows attachment to small intestine. --non sporeforming --short rods

How is EHEC transmitted?

It is transmitted by food and water contaminated, but it can also transmitted via person-to-person contact.

Describe the treatment of Influenza.

Oseltamivar and Zanamivir, also can inhibit hemagglutinin

Describe the pathogenesis of papillomavirus.

Part of virus life cycle is incorporation into host DNA; types of the virus are tissue specific

What measures could you take to control Chlamydia?

Really it comes down to promoting safe sex using condoms, promoting sexual health awareness, and promoting STD testing. Chlamydia can cause sterility in women.

What is the target of Rifampin?

Rifampin is an antibiotic that inhibits DNA-dependent. RNA polymerase actively in susceptible cells.

Describe the microbe features of the Influenza A virus.

Segmented negative strand ssRNA virus --enveloped with hemagglutinin and neuraminidase as a nucleocapsid

What is the target of Quinolones?

Target DNA replication

What is the target of Erytromycin and other protein synthesis inhibitors?

Target DNA structure and replication.

What is the target of Penicilin and other beta-lactam antibiotics?

Target cell wall synthesisi