Microbiology Drugs Flashcards
Antimicrobials drugs that inhibits the folic acid synthesis and reduction ( DNA methylation) ;
- Sulfonamides.
- Trimethoprim
Which type of penicillin use as IV and IM ?
Penicillin G
Which type of penicillin used as oral ?
Penicillin V
Which Antimicrobials drugs contains Beta lactam ring ?
- Penicillin.
- Cephalosporins.
- Carba-penems
- Monobactam (Aztreo-nam).
Mechanism of penicillin:
Penicillin break down of the bacterial cell wall by inhibition of the cross-linking of transpeptidase, therfore, it’s prevent the cell wall formation— lead to increasing the osmotic pressure in the cell —- lyisis of the cell .
Penicillin doesn’t affects the human cell wall due to :
Because the human cell wall consist of L-Ala (not D-Ala like the bacteria )
Cross linking of the bacterial cell wall occurs by :
Transpeptidase( penicillin binding protein )
Clinical use of penicillin :
- Gram + (s.pneumonea, s. Pyogenes {specially for sore throat}, Actinomyces )
- Gram (-) cocci : mainly(N.meningitis)
- Spirochets :( T.pallidum)
- Penicillinase sensitive.
What is penicillinase ?
B-lactamase enzyme present in the periplasm of the gram (-) bacteria .
Mechanism of penicillinase “B-lactamase” ?:
Destruction of beta lactam ring.
Adverse effect of penicillin:
- Hypersinsivity (type1,2,3,4)
- Jaresch-herxeimer reaction
What’s the hypersinsivity reaction of penicillin ?
- Type 1 hypersinsivity
- Type 2 hypersinsivity ( Hemolytic anemia ).
- Type 3 hypersinsivity (Serum sickness).
- Type 4 hypersinsivity (Maculopapular rash).
Hemolytic anemia that cause by penicillin, which typer of hypersinsivity reaction is considered?
Typer 2 hypersensitivity
Maculopapular rash that cause by penicillin, which type of hypersinsivity reaction considered ?
Type 4 hypersinsivity reaction
Resistance of penicillin by :
- Penicillinase(B-lactamase)
- Modification of PBP( changing of penicillin-binding protein )
- Reduced bacterial cell pentration by:
*Gram (-) bacteria “that have outer membrane “.
*decrease number of porins channel ( that responsible for transporting chemical element to outside and inside the bacterial call ).
Which drug increase the duration of penicillin in the blood by decrease the penicillins renal secrtion?
Probencid
B-lactamase inhibitors :
- Clavulanic acid
- Sul-bactam
- Tazo-bactam
- Avi-bactam
Penicillinase-sensitive penicillin (anino-penicillins): oral, IV ..?
- Amoxicillin (oral)
- Ampicillin (IV)
Mechanism of Penicillinase-sensitive penicillin :
The same with penicillin but have more Penetration of porin channels of gram (-) bacteria .
Augmentin it’s :
Amoxicillin + clavulenic acid
Augmentin (Amoxicillin +clavulanic acid) uesed for :
Resistance cases of otitis media
Unasyn (Ampiccillin +sulbactum) uesed for :
Surgical infection
Clinical use of penicillinase-sensitive penicillin :
- HHELPSS :
- H-influenza,
- H-pylori,
- E.coli,
- Listeria
- Proteus
- Salmonella,
- Shigella, ++++ enterococci
Penicillinase- resistance penicillins (antistaphylococcal penicillins ):
- Dicl-oxa-cillin.
- Naf-cillin.
- Oxa-cillin.
- Methi-cillin.
Mechanism of Penicillinase- resistance penicillins (antistaphylococcal penicillins ):
Same with penicillin.
Why Penicillinase- resistance penicillins are resistance to penicillinase ?
Because “bulky side chain R group “ block access of B-lactamase to B-lactamase ring.
Clinical use of Penicillinase- resistance penicillins (antistaphylococcal penicillins ):
S.aureus skin infection{cellulitis and impetigo, folliculitis } (except MRSA resistance)
Adverse effect of Penicillinase- resistance penicillins (antistaphylococcal penicillins ):
- Hypersinsivity
- Acute Interstitial nephritis.
Antipseudomonal penicillins :
- Pi-pera-cillin,
- Ticar-cillin .
Piperacillin, ticarcillin used for :
1.Pseudomonas
2. Most gram (+) bacteria
Ticarcillin + clavulonate =
Time-nitin
Piperacillin+ tazobactam =
Zosyn
Penicillin is bactericidal or bacteriostatic
Bacteriocidal
Cephalosporins is bactericidal or bacteriostatic
Bactericidal
Mechanism of cephalosporins ?
B-lactam drugs that inhibit cell wall synthesis but are less susceptible to penicillinase .
Which organism not covered (not effected ) by 1st-4th generation of cephalosporins ?
LAME
1. Listeria
2. Atypical {mycobacterium, chlamydia}
3. MRSA
4. Enterococci
1st generation of cephalosporin:
- Cefa-zolin,
- Ceph-alexin.
2nd generation of cephalosporin:”
- Cefa-clor,
- Cefo-xitin,
- Cefu-roxime.
3rd generation of cephalosporin :
- Cef-triaxone,
- Cef-tazidime
- Cef-podoxime,
- Cefo-taxime
4th generation of cephalosporin:
Cefepime
5th generation of cephalosporin:
Cefta-roline
Clinical use of 1st generation of cephalosporin:
** KEP:-
1. Proteus
2. E.coli
3. Klebsiella pneumonia
Which drug used prior to surgery to prevent s.aureus wound infection ?
Cefazolin
Clinical use of 2nd generation of cephalosporin
KEP +SHEN
1. H-influnza
2. Enterobacter
3. Niesseria
4. Serratia
Which drug from 3rd generation of cephalosporin used for meningitis and gonorrhoea and disseminated Lyme disease ?
Ceftriaxone
Which drug from 3rd generation of cephalosporin used for pseudomonas?
Ceftazidime
Which generation of cephalosporins covered the listeria and MRSA and enterococcus but not covered the pseudomonas ?
5th genereation(ceftraoline)
Which drugs have this adverse effects: hypersinsivity reaction, autoimmune hemolytic anemia, disulfiram-like reaction, vit K deficiency , hypoprothombinemia, increasing of neurotoxicity of aminoglycosides ?
Cephalosporins
Carba-penems drugs :
- Imi-penem.
- Mero-penem.
- Erta-penem.
- Dori-penem.
Which drugs that inhibitor of renal dehydropeptidase 1?
Cilastatin
Why the 5th generation of cephalosporins covers the listeria and enterococcus and MRSA ?
Because it’s bind on another site that the fist 4 generation bind to it, it bind to PBP2a
Which drug of carbapenems inhibit by renal dehydropeptidase ?
Imipenem
Which drug of carbapenems have CNS toxicity side effect (seizures)?
Imipneme
Why the meropneme bitter than imipneme ?
- Because the imipneme break down by renal dehydropeptidase-1
- Because the imipneme have CNS toxicity side effect (siezures)
Monobactams (aztreonam) mechanism of action:
- Prevent the peptidoglycan cross-linking by binding to PBP-3 (only in G-negative).
- Synergistic with aminoglycosides .1+1=3
Clinical use of monobactams :
- For penicillin allergic.
- Patient those with renal insufficiency who can’t tolerate aminoglycosides
- Gram (-) rod only
Which drug that have the highly resistance to B-lactamase ?
Carbapenems
Which drug that have highly sensitive to B-lactamase ?
Penicillins
Penicillin binding protein :
1. PBP-3 :?
2. PBP-2a ?
- PBP-3: aztreonam
- PBP-2a: ceftaroline.
اقوى سلاح لل: gram - bacteria
B-lactamase
Mechanism of vancomycin :
Inhibit cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursor .
Why Vancomycin can’t affects the gram (-) bacteria ?
Because it has too large molecule that can’t pentrate the outer membrane of the gram (-) bacteria
Which drugs cause red man syndrome as adverse effects?
Vancomycin
Which drug can cause nephrotoxicity , ototoxicity, thrombophlebitis?
Vancomycin
Which syndrome characterised by diffuse flushing of the whole body, and non specific mast cell degranulation “histamin release” ?
Red man syndrome
Treatment of red man syndrome. :
- Stop the drug
- Give Anti-Histamines
- Restart the medication
Mechanism of resistance of vancomycin ?
Via amino acid modification of D-Ala D-Ala to D-Ala D-Lac
Treatment of MRSA by:
.6 ادويه
Treatment of VRSA by :
- Quinu-pristin
- Dalfo-pristin
All protein synthesis inhibitor are bacteriostatic except :
Aminoglycosides
Amino glycoside is bactericidal due to
Miss reading of mRNA
Which of protein synthesis inhibitor are variable( bacteriostatic + bacteriocaidal) ?
- Dlafo- pristin.
- Quinu-pristin.
Protein synthesis inhibitor divided into : 30s inhibitor and 50s inhibitor, which drug are the 30s inhibitors ?
- Aminoglycosides
- Tetracycline
Protein synthesis inhibitor divided into : 30s inhibitor and 50s inhibitor, which drug are the 50s inhibitors ?
- Chloramphenicol
- Clindamycin
- Marcrolides
- Linezolides
- Strepto-gramins
Aminoglycosides drugs:
- “GNATS “
1. Genta-mycin
2. neo-mycin
3. Amikacin
4. Tobra-mycin
5. Strepto-mycin
Mechanism of aminoglycosides :
- Irreversible inhibtion of initiation complex though binding to 30s subunit causing missreading of mRNA
- Block translocation
Why aminoglycosides ineffective aginst anaerobes ?
Because it require O2 for uptake
Which drugs use for severe gram (-) rod infection , and also can be synergistic with B-lactam antibiotics ؟
aminoglycosides
Which aminoglycosides used for bowel surgery and hepatic encephalopathy ?
Neomycin
Aminoglycoside it synergistic with B-lactam antibiotics , it’s rare to used alone. Which aminoglycoside drug that use with vancomycin to treatment the endocarditis ?
Vancomycin + gentamycin
Aminoglycoside it synergistic with B-lactam antibiotics , it’s rare to used alone. Which aminoglycoside drug that use with ampicillin to treatment the neonatal meningitis ?
Ampicillin +gentamycin
Advers effects of aminoglycosides :
NNOT
1. Nephrotoxicity,
2. Neuromuscular blockage (⬇️ Ach) ,
3. Ototoxicity (specially when used with loop diuretics,
4. Teratogen
Which drug have this adverse effects: Nephrotoxicity, neuromascular blockage (⬇️ Ach) , ototoxicity (specially when used with loop diuretics, teratogen
Aminoglycoside
Mechanism of resistance of aminoglycosides :
- Bacterial transferase enzyme inactivate the drug by :
- Acetylation
- Phosphorylation
- Adenylation
Bacterial transferase enzyme inactivate the aminoglycoside by :
1.acetylation
2. Phosphorylation
3. Adenylation
Tetracycline drugs :
- Tetra-cycline
- Doxy-cycline
- Mino-cycline
Mechanism of tetracycline :
Bind to 30s and prevent attachment of aminoacyl-tRNA
Don’t take tetracycline with milk (calcium) antacid or iron due to :
The milk , antacids and irons decrease the absorption of the tetracycline in the gut.
Which drug have ability to accumulate intracellularly and make them very effective aginst rickettsia and chlamydia ?
Tetracycline
Which drug can use for borrelia burgdorferi and. M.pneumoniae, rickettsia and chlamydia and also used for treat acne ?
Tetracycline
Which drug can used in patient with renal faliure and have effect aginst MRSA?
Doxycycline
Which type of tetracycline not used as antibiotics, used as ADH antagonist, so it’s given for SIADH?
Demeclocycline
Which drugs have this adverse effects :
GI distress, discoloration of teeth, inhibition of bone growth in children , photosensivity, contraindicated in pregnance ?
Tetracycline
Which drug have this mechanism of resistance : ⬇️ Uptake or ⬆️ efflux out of bacterial cell by plasmid -encode transport pumps ?
Tetracycline
Clinical uses for tetracycline :
- Zoonosis : borrelia, M.pneumonea.
- Intracellular orgasnism : chlamydia, rickettsia
- Acne: prpprionecacterium
- Doxycycline : 1. Can use in case-of bacterial infection in patient with renal failure because it does not effect on kidney 2. MRSA
Drugs with photo-sensivity :
- Aminoglycosides
- Tetracycline
- Sulfonamides
Gly-cyl-cycline: drug
Tige-cycline.
What is tigecycline ?
tetracycline derivative bind to 30s and inhibit protein synthesis
Clinical use of tigecycline :
For multidrug-resistance (MRSA,VRE)
Mechanism of action of chloramphenicol :
Bind to 50s and inhibit peptidyltransferase
Clinical use for chloramphenicol:
- Meningitis,
- Rocky moutain spotted fever (in case of pregnancy for the 1st and 2nd trimester only )
Which drug if used it the pregnant women in the first and seconde trimester does not have side effect, but if she used it in the 3d trimester can lead to gray baby syndrome ?
Chloramphenicol
Gray baby syndrome cause by which enzyme lack in liver ?
Liver UDP-glucu-rony-ltransferase.
Which drug have this mechanism of resistance: plasmid-encoded acetyltransferase inactivates the drug
Chloramphenicol
Which syndrome characterised by : vomiting, ashen grey color of the skin, poor muscle tone, cyanosis, CV collapse ?
Gray baby syndrome
- Gray baby syndrome cause by :
- Gray man syndrome cause by :
- Red man syndrome cause by:
- Gray baby syndrome cause by :chloramphenicol
- Gray man syndrome cause by :amidarone
- Red man syndrome cause by: vancomycin
Macrolides:
- Az-thromycin
- Clari-thromycin
- Erthromycin
Mechanism of macrolides:
Inhibition of protein synrthesis by blocking translocation , bind to the 23S rRNA of the 50s subunit
Mechanism of clindamycin :
Block peptide transfer (translocation) at 50s ribosoma subunit “ same as macrolides
Which drug Block peptide transfer (translocation) at 50s ribosoma subunit “ same as macrolides
Clindamycin
Clinical uses of clindamycin :
- Anaerobic infection
- Group A strep infection
- MRSA
Which drugs cause pseudomembranous colitis as side effects ?
- Clindamycin
- Streptogramin
Mechanism of resistance of clindamycin :
As macrolides “methylation”
Oxazolidinones drug:
Linezolid
Mechanism of linezolid:
Inhibit protein synthesis by binding to 50s subunit- prevent formation of initial complex
Clinical uses of linezolid:
Last line for bacterial resistance (MRSA,VRE)
Which drug have thius adverse effects: bone marrow supression especially thrombocytpnea), peripheral neuropathy, serotonin syndrome when given with SSRIs (selictive serotonin reuptake inhibitors)
Linezolid
How linezolid lead to serotonin syndrome ?
When giver the linezolid with SSRIs , the linezolid is weak MAOIs (increase serotonin)+ SSRIs also increase the sertonin, taking the twice togther lead to serotonin syndrome
Which drug have point mutation of ribosomal RNA as mechanism of resistance ?
Linezolid
Which drugs can cause prephral neuropathy ?
- Linezolid
- isoniazid
Azithromycin, larithromycin, erthromycin, for which group of drug belongs?
Microlides
Which drug have this mechanism of action: ihibit protein synthesis by blocking translocation, bind to the 23s rRNA of the 50s ribosomal subuint?
Macrolides
How the macrolides effect aginst intracellular organisms?
By concentration inside the macrophage and other cells
Clinical use of macrolides :
- Atypical pneumonias ( Mycoplasma,chlamydia , legionella)
- Upper respiratory infection :( str. Pneumonia, str. Pyogenes, proteussis ).
- Streptococcal infection in patient allergic to penicillin.
Which drug of microlides can used in motility disoreder of GIT ( eg, gastroparesis) ?
Erthromycin
Erthromycin bind to which receptor in GIT, that leade to smooth muscle contraction ?
Motilin receptor
adverse effects of macrolide
GAARE
1. Gastrointistinal motility issues,
2. Arrhythmia
3. Acute cholestatic hepatitis
4. Rash
5. Esinophilia
Which macrolides inhibit cytochrome p-450 that lead to increase serum concentration of theophyline, oral anticoagulants ?
Erthromycin and clarithromycin
Mechanism of resistance of macrolides:
Methylation of 23s rRNA-binding site ,prevent binding of drugs.
Sulfonamides drugs :
- Sulfa-methoxazole (SMX)
- Sulfa-soxazole
- Sulfa-diazine
Which drug have this mechanism : inhibit dihydropteroate synthesis ?
1.Sulfonamide
2. Dapsone
Which bacteriostatic drug converts to bacteriocidal when combined with trimethoprim ?
Sulfonamides
Which drug have the following adverse effects : hypersensivity reaction, hemolysis if G6PD deficient, bind to albumin ?
Sulfonamides
Which drug have the following mechanism of resistance :
1. Altered enzyme ( bacterial dihydropteroate synthase)
2. ⬇️ uptake
3. ⬆️PABA synthesis
Sulfonamides
Which drug have similar mechanism to sulfonamides but structurally distinct agent, and use for leprosy and pneumocystis jivovecii prophylaxis ?
Dapsone
Which drug inhibit bacterial dihydrofolate reductase, and may cause megaloblastic anemia leukopenia, granulocytopenia?
Trimethoprim
Trimethoprim side effects :
Bone marrow supression:
1. Megaoblastic anemia
2. Leukopnia
3. Granulocytopenia
Which drug causing sequential block of folate synthesis in case of used in combination with sulfonamides ?
Trimethoprim
How the trimethoprim lead to megaloblastic anemia ?
By effect on human dihydrofolate reductase
Which drugs are vairable (static\sidal) and synthesized by the streptomycess virginia ?
Strepto-gramins:- quinupristin, dalfopristin
Strepto gramins used for:
- MRSA
- VRE
- Staph
- Strept skin infection
Fluroquinolones drugs :
- Cipro-floxacin
- Nor-floxacin
- Levo-floxacin
- Oflo-floxacin
- Moxi-floxacin
- Gemi-floxacin
- Eno-xacin