L6 Intro to bact

Question 1

LO2: comp and contr key props bact and virs as distinct from euk.

Answer 1

-euk eg yeast, protozoan- mm/um.
prok smaller um, no nuc mem or mem organelles, have D and RNA, one chrom, no introns, coupled trans/l, v labile mRNA, 70S ribos, peptidoglycan wall. vir oblig intracell have D or RNA, nm.

Question 2

LO3: sig of gram and acid fast stain for classif and detec bact.

Answer 2

-gram- gram pos peptidoglycan prevs extrac so BLUE
gram neg thin peptidog and outer mem PINK.
pos crystal violet binds neg cell compons. iodine complexes with it. acetone/methanol extract through gram neg only. red stain gram neg.
-acid fast- eg auramine fluor, Zeihl Neelson bright field. for mycobact- no peptidog. mycob wall complex- PM, peptidog, arabinogalac, lip rich mycolic ac, gl’s.
smears for acid fast bacilli rap but insensit.

Question 3

gram pos cocci.

Answer 3

• staph aureus- skin infec, pneum, food pois, TSS, bacteraemia.
• strep pyogenes- pharyngitis, scarlet fever, impetigo, cellulitis, can be invas.
• Group B strep- sepsis and mening esp neonate. pneum.
• strep pneumoniae- pneum, poss invas.

Question 4

gram neg cocci.

Answer 4

• neiss mening- mening, sepsis.

- neiss gonorrhoeae.

Question 5

gram pos bacilli.

Answer 5

• clostrid perfringens- food pois, bacteraemia, necrois, gas gang, cholecystitis.
• C diff- colitis.

Question 6

gram neg bacilli.

Answer 6

• e coli- food pois, cholecyst, bacteraemia, UTI, cholangitis, neon mining, pneum.
• salmonella- food pois, typhoid fever, paratyphoid fev.
• shigella- shigellosis, dysentery.

Question 7

LO1: briefly answer:

Answer 7

• what is infec- est of an org on/in host assoc with its multip and dam to/dysfunc of host specif rel to that org or its prods.
• what causes infec- pathogenic microbes (kochs postulates)- vir/prion/bact(archaea)/protoz/ fungi/helminths/arthropods infestat. and mechs of pathogenesis.
• why partic indivs get partic infec- encount dose and route. virul vs host resis. innate and adap imm.
• what infls outcome of infec- encount dose and route, virul vs resis, inn and adap imm, speed of diag and tx.