bacterial infections

Question 1

what are the ESCAPE pathogens which escape effects of antimicrobial agents, and which are gram +ve/-ve

Answer 1

Enterococcus faecium, Staphylococcus aureus, Clostridium difficle (all gram +ve); Acinetobacter baumanii, Pseudomonas aeruginosa, Enterobacteriaceae (all gram -ve)

Question 2

drug resistance of E. coli

Answer 2

multi-drug resistant, but still sensitive to carbapenems

Question 3

target pathway and protein of cephalosporins and carbapenems (B-lactam antibiotics)

Answer 3

inhibit peptidoglycan synthesis, inhibit activity of penicillin binding proteins

Question 4

what do bacteria that are resistant to cephalosporins (e.g. E. coli) express (still sensitive to carbapenems)

Answer 4

ESBL (extended spectrum beta latamase) encoded on plasmid which cleaves cephalosporin

Question 5

what do bacteria that are resistant to cephalosporins express

Answer 5

carbapenemase enzyme encoded on tranposon which cleaves carbapenem

Question 6

describe Klebsiella pneumoniae infection and resistance

Answer 6

causes UTI or respiratory tract infections, with a high proportion resistant to cephalosporins, fluroquinolones and aminoglycosides (infrequently carbapenems)

Question 7

describe Pseudomonas aueruginosa resistance

Answer 7

most multi-drug resistant, with some resistant to carbapenems

Question 8

what is most important cause of antimicrobial resistant infection worldwide

Answer 8

MRSA

Question 9

target pathway and protein of methicillin (B-lactam antibiotics)

Answer 9

inhibit peptidoglycan synthesis, inhibit activity of penicillin binding proteins

Question 10

describe how MRSA has resistance to methicillin (B-lactam so inhibits peptidoglycan synthesis by inhibiting activity of penicllin binding proteins)

Answer 10

express additional penicillin binding proteins, so still function in presence of antibiotic and synthesise peptidoglycan

Question 11

target pathway and protein of vancomycin

Answer 11

inhibit peptidoglycan synthesis by binding to peptidoglycan precursor

Question 12

describe how CRE has resistance to vancomycin

Answer 12

multiple protein genes encoded on plasmid or transposon result in synthesis of different peptidoglycan precursor

Question 13

2 causes of antibiotic resistance in hospitals

Answer 13

prophylactic antibiotics, inappropriate prescribing