Final Flashcards
(109 cards)
Since 60% of pneumonia is caused by S. pnuemoniae, what are the other bacteria that cause it?
Chlamydophila (Chlamydia) pneumoniae Mycoplasma pneumoniae Haemophilus influenzae Pneumocystis carinii
What are some symptoms of pneumonia and whats its incubation period?
abrupt onset fever, chills chest pain difficulty in breathing productive cough rust coloured sputum incubation: 1 - 3 days
How do you treat pneumonia?
penicillin G erythromycin (azithromycin, clarithromycin) ceftriaxone vancomycin (usually only for HAP)
What happens during stage 1 of pneumonia?
bacteria stimulate flow of fluid into alveoli fluid promotes growth of the bacteria fluid allows spread of bacteria to other alveoli and lobes loss of air exchange capacity due to fluid
What happens during stage 2 and 3 of pneumonia?
second stage (early consolidation) infiltration of the alveoli by neutrophils and red blood cells phagocytosis of bacteria the point where infection brought under control third stage (late consolidation) alveoli are packed full of neutrophils with ingested bacteria clearance of bacteria from the lungs occurs “hepatization” of lungs, alveoli look like hepatocytes
Describe stage 4 and what is special about pneumonia?
neutrophils leave macrophage clean up debris Pneumonia lack of permanent damage very little fibrous scar tissue
What bacteria causes epiglotittis?
epiglottitis is nearly always caused by H. influenzae B
Give me some characteristics for Mycoplasma pneumoniae?
the mycoplasma are the smallest free-living bacteria they do not produce peptidoglycan not sensitive to b-lactams and vancomycin membranes contain sterols can take up to 3 weeks to grow colonies
What must the mdeia contain in order to grow M. pnuemoniae?
isolation media contain peptone enriched with yeast extract and serum to provide cholesterol also b-lactam antibiotics to suppress other bacterial contaminants methylene blue can be added to suppress all other Mycoplasma species and/or glucose as M. pneumoniae is the only species which ferments glucose to acid
Give me some characteristics of Klebsiella pnuemoniae.
Gram-negative bacillus, lactose positive with gas production MR-VP (- +) Indole negative, citrate positive (E. coli is MR-VP + - and indole +, citrate -)
What are some characteristics of the Influenza virus?
member of the Orthomyxoviridae a single-stranded, negative sense RNA virus with a segmented genome enveloped virus (host cell membrane) the surface of the virus is covered with spikes called peplomers there are two types of spikes, one is the hemagglutinin and the other is the neuraminidase
In the influenza virus, how many genomes are produced and what are the proteins produced as a result?
8 RNA segments each codes for one or more proteins, 10 in total HA – hemagglutinin and NA – neuraminidase Matrix protein-1, M-2 Nucleoprotein Polymerase B1, B2 and A Non-structural-1 and NS-2
How does the influenza virus escape the host cell?
HA binds the virus to its receptor sialic acid tipped galactose carbohydrates NA cleaves sialic acid from the end of the receptor to allow the newly formed virus to escape
Where are the matrix proteins found in the influenza virus and which is the most important?
M1 coats the inside of the envelope M1 is the most important protein for the structure, assembly and budding of the virus M2 is found in small amounts in the envelope
What are the symptoms of influenza virus and how is it transmitted?
fever/chills headache, muscle aches and pains malaise cough lasting 3 - 7 days Through water droplets spread by coughing and sneezing
How does the influenza virus enter the cell?
the influenza hemagglutinin binds to sialic acid containing glycolipid/glycoprotein receptor on epithelial cells viral particles are taken up by receptor-mediated endocytosis and fuse with a lysosome the drop in pH in the virus containing endosome causes a conformational change in hemagglutinin. Part of the hemagglutinin is now exposed and can mediate fusion between the viral envelope and the endosome membrane nucleocapsids are then liberated into cytoplasm and move to the nucleus
How does the Influenza virus replicate in the host cell?
viral RNA is replicated in cell nucleus using viral encoded RNA-dependent RNA polymerase 10 transcripts produced (+ sense mRNA) viral mRNAs “steal” the 5’ cap and 3’ polyA tail from preformed cellular mRNAs viral proteins are synthesised nuclear replication of the original 8 (-) strand RNAs
What is the causative agent of Typhoid?
Salmonella Typhi (
The fatality rate of Typhoid is ____
10%
How is Typhoid spread?
Usually food or water borne, but mostly food borne in developed countries
What organisms cause symptoms extremely similar to Typhoid?
Salmonella Paratyphi A, B, C and S. Typhimurium
S. Typhi and S. Typhimurium share ___% of their genes. How do they differ? Why is this relationship interesting?
89%. S. Typhi affects only humans whereas S. Typhimurium affects lots of mammals and even reptiles. S. Typhi evolved relatively recently and has a large amount of genes that are “turned off”, probably resulting in the limited host range.
What is it called when one of two closely related organisms has genes that are inactive, causing the differences between the two
Reductive evolution
What countries are hot spots for Typhoid?
South east asia is main hotspot, then rest of Asia, Africa,and South America