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FirstAid:Microbiology > Microbiology:Antimicrobials > Flashcards

Microbiology:Antimicrobials Flashcards

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1
Q

What is the general MOA of sulfonamides and trimethoprim?

A

Block nucleotide synthesis by inhibiting folic acid synthesis

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2
Q

What antibacterial blocks mRNA synthesis?

A

Rifampin

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3
Q

What are the main uses of penicillin?

A

Gram + (S. pneumoniae, S. pyogenes, Actinomyces)
Neisseria meningitidis
Treponema pallidum
Syphilis

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4
Q

2 main toxicities of penicillin

A

Hypersensitivity rxns

Hemolytic anemia

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5
Q

Resistance to penicillin

A

Beta lactamases cleave the beta lactam ring

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6
Q

What makes oxacillin, nafcillin, and dicloxacillin penicillinase resistant?

A

Bulky R group blocks the access of beta lactamase to the beta-lactam ring

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7
Q

What is the key clinical use of oxacillin, nafcillin, and dicloxacillin?

A

S. aureus (except MRSA)

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8
Q

What are the two main SEs of penicillinase-resistant penicillins like oxacillin, nafcillin, and dicloxacillin?

A

Hypersensitivity rxns

Interstitial nephritis

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9
Q

Does ampicillin or amoxicillin have greater oral bioavailability?

A

AmOxicillin

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10
Q

What are the uses of ampicillin and amoxicillin? (7)

A 
Haemophilis influenzae
E. coli
Listeria monocytogenes
Proteus mirabilis
Salmonella
Shigella
Enterococci
HELPSS kill Enterococci
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11
Q

What are the three main toxicities of ampicillin and amoxicillin?

A

Hypersensitivity reactions
Ampicillin rash
Pseudomembranous colitis

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12
Q

What are amoxicillin and ampicillin often combined with?

A

Beta lactamase inhibitor like clavulanic acid

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13
Q

What are the two antipseudomonal beta lactams?

A

Ticarcillin
Piperacillin
**use with calculanate

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14
Q

What is the main SE of piperacillin and ticarcillin?

A

Hypersensitivity rxns

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15
Q

What are the beta lacatamase inhibitors?

A

Clavulanate
Sulbactam
Tazobactam

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16
Q

Are penicillins or cephalosporins more susceptible to penicillinases?

A

Penicillin

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17
Q

What are 4 organisms typically not covered by cephalosporins? (LAME)

A

Listeria
Actinomyces
MRSA
Enterococci

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18
Q

What are 2 first generation cephalosporins?

A

Cefazolin

Cephalexin

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19
Q

What do the 1st generation cephalosporins like cefazozlin and cephalexin cover?

A 
PEcK 
Gram positive cocci
Proteus mirabilis
E. coli
Klebsiella
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20
Q

Cefazolin is used prior to surgery to prevent:

A

S. aureus wound infections

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21
Q

What are 3 second generation cephalosporins?

A

Cefoxitin
Cefaclor
Cefuroxime

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22
Q

What are the second generation cephalosporins used for?

A 
HEN PEcKS
Gram positive cocci
Haemophilus influenzae
Enterobacter
Neisseria
Proteus mirabilis
E. coli
Klebsiella
Serratia
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23
Q

What are the third generation cephalosporins used for?

A

Serious gram negative infections resistant to other beta lactams

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24
Q

What are three 3rd generation cephalosporins?

A

Ceftriaxone
Cefotazime
Ceftazidime

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25
What 3rd generation cephalosporin is used for meningitis and gonorrhea?
Ceftriaxone
26
What 3rd generation cephalosporin is used for P. aeruginosa?
Ceftazidime
27
What is the key fourth generation cephalosporin? | What does it have high activity against?
Cefepime | P. aeruginosa
28
Main SEs of cephalosporins
Hypesensitivity rxns | Vitamin K deficiency
29
What should you be cautious of when you combine cephalosporines with aminoglycosides/
Can incresae the nephrotoxicity
30
What is a monobactam that is resistant to beta lactamases?
Aztreonam
31
How does Aztreonam work? | What is it synergistic with?
Prevents peptidoglycan cross-linking by binding PBP3 | Aminoglycosides
32
What is the clinical use of aztreonam?
Gram negative rods only Used for penicillin allergic patients and those with renal insufficiency (cant tolerate aminoglycosides) **usually nontoxic, with only minor GI upset
33
What is a broad spectrum, beta lactamase resistant carbapenem? What is it always administered with?
Imipenem | Cilastatin (inhibitor of renal dihydropeptidase I)
34
What is the clinical use of imipenem?
Gram positive cocci, gram negative rods, and anaerobes | Limited use due to bad side effects
35
What are the side effects of imipenem?
GI distress Skin rash CNS toxicity
36
What is the MOA of vancomycin
Inhibits cell wall peptidoglycan formation by binding D-ala D-ala portion of cell wall precursors
37
What is vancomycin used for?
Serious, gram positive infections only | MRSA, enterococci, and C. diff (oral)
38
What is the toxicity of vancomycin?
Nephrotoxicity Ototoxicity Thrombophlebitis Red man syndrome
39
How can red man syndrome with vancomycin be prevented?
Antihistamines | Slow infusion rate
40
What leads to resistance to vancomycin?
D-ala D-ala to D-ala D-lac
41
What antibacterial types interact with 30s?
Aminoglycosides (cidal) | Tetracycline (static)
42
What antibacterial types interact with 50s?
Chloramphenicol Clindamycin Macrolides Linezolid
43
What are the important aminoglycosides?
``` Gentamicin Neomycin Amikacin Tobramycin Streptomycin ```
44
What is the MOA of aminoglycosides?
Inhibit the formation of the initiation complex and causing misreading of mRNA Block translocation
45
What are aminoglycosides used for?
Severe gram negative rods Aerobes only because the require O2 for uptake **Neomycin for bowel surgery
46
What are the main SEs of the aminoglycosides?
Nephrotoxicity (esp with cephalosporins) Ototoxicity (esp with loop diuretics) Neuromuscular blockage Teratogen
47
Resistance to aminoglycosides?
Transferase enzymes that inactivate the drug by acetylation, phosphorylation, or adenylation
48
What are the 4 key tetracyclines?
Tetracycline Doxycycline Demeclocyline Minocycline
49
What is the MOA of tetracyclines?
Bind to the 30s and prevent attachment of aminoacyl-tRNA
50
Which tetracycline can be used in renal failure?
Doxycycline (fecal excretion)
51
What should tetracyclines not be injested with?
Milk Antacids Iron-containing preparations **divalent cations inhibit absorption
52
The tetracycline demeclocycline is rarely used as an antibiotic--what is it used for?
ADH antagonist, acts as a diuretic in SIADH
53
What are the clinical uses of tetracyclines?
Borrelia burgdorferi M. pneumoniae Rickettsia and Chlamydia (due to ability to accumulate intracellularly)
54
What is the mechanism of tetracycline resistance?
Decreased uptake into cells | Increased efflux out of cells by plasmid encoded transport pumps
55
What are the three key macrolides?
Azithromycin Clarithromycin Erythromycin
56
What is the MOA of the macrolides?
Inhibit protein syn by binding 23S rRN of the 50s subunit, prevent translocation (macroSLIDE)
57
What are the uses of the macrolides?
Atypical pneumonia (Mycoplasma, Chlamydia, Legionella) STDs (chlamydia) Gram positive cocci (patients allergic to penicillin)
58
What are the toxicities associated with macrolides?
``` Motility problems Arrythmias from prolonged QT Cholestatic hepatitis Rash eOsinophilia ```
59
What do macrolides increase the serum concentration of?
Theophyllines | Oral anticoagulants
60
What is the mechanism of resistance to macrolides?
Methylation of 23s rRNA binding site
61
What is the MOA of chloranphenicol?
Blocks peptidyltransferase at 50s ribosomal subunit
62
What is chloramphenicol used for?
Meningitis (H. inf, N.meningitidis,S.pneumo)
63
What is the toxicity of chloramphenicol?
``` Anemia (dose dependent) Aplastic anemia (dose independent) Grey baby syndrome ```
64
What causes grey baby syndrome in premature infants when they are given chloramphenicol?
Lack liver UDP-glucuronyl transferase
65
Mechanism of resistance to chloramphenicol?
Plasmid-encoded acetyltransferase that inactivates the drug
66
What is the MOA of clindamycin?
Blocks peptide transfer at the 50s ribosomal subunit
67
What is clindamycin used for?
Anaerobic infection (Bacteroides facilis, Clostridium perfringens) in aspiration pneumonia or lung abscesses Oral infections with mouth anaerobes **Treats anaerobic infections over the diaphragm while metronidazole treats them below the diaphragm
68
What are the main SEs of clindamycin?
Pseudomembranous colitis Fever Diarrhea
69
What are the 3 main sulfonamides?
Sulfamethoxazole (SMX) Sulfisoxazole Sulfadiazine
70
What is the MOA of sulfonamides?
PABA antimetabolites that inhibit dihydropteroate synthase (PABA + pteridine to dihydropteroic acid)
71
What are the main SEs of sulfonamides?
``` Hypersensitivity reactions Hemolysis in G6PD deficiency Nephrotoxicity (tubulointerstitial nephritis) Photosensitivity Kernicterus in infants **displace other drugs from warfarin ```
72
What is the mechanism of resistance to sulfonamides?
Altered bacterial dihydropteroate synthase Decreased uptake Increased PABA synthesis
73
What is the MOA of trimethoprim?
Inhibits bacterial dihydrofolate reductase
74
What is the clinical use of sulfonamides?
Gram positive and gram negative Nocardia Chlamydia Triple sulfas or SMX for UTI
75
What is the clinical use for trimethoprim?
Used in combo with sulfonamides to cause sequential block of folate synthesis Combination used for UTIs, shigella, salmonalla, Pneumocystis jirovexii pneumonia
76
Toxicity of trimethoprim
Megaloblastic anemia Leukopenia Granulocytopenia
77
What are some of the fluoroquinolones?
``` Ciprofloxacin Norfloxacin Levofloxacin Ofloxacin Sparfloxacin Moxifloxacin Gatifloxacin Enoxacin Nalidixic acid (quinolone) ```
78
What is the MOA of the fluoroquinolones?
Inhibit DNA gyrase and topoisomerase IV
79
What is the clinical use of fluroquinolones?
Gram negative rods of urinary and GI tracts (including pseudomonas), Neisseria, and some gram +
80
What is the toxicity of fluroquinolones?
``` GI upset Superinfections Skin rashes Headache and dizziness Tendonitis and tendon rupture Leg craps and myalgias **some may prolong QT ```
81
Resistance to fluroquinolones?
Chromosome-encoded mutation in DNA gyrase Plasma mediated resistance Efflux pumps
82
What is the MOA of metronidazole?
Forms free radical toxic metabolites in the bacterial cell that damage DNA
83
What are the clinical uses for Metronidazole?
``` Giardia Entamoeba Trichomonas Gardnerella vaginalis Anaerobes (Bacteroides and C. diff) H. Pylori (with clarithromycin and PPi) ```
84
Toxicity of metronidazole?
Disulfiram-like rxn with alcohol Headache Metallic taste in the mouth
85
What drug is used for tuberculosis prophylaxis?
Isoniazid
86
What drugs are used for tx of tb?
``` Rifampin Isoniazid Pyrazinamide Ethambutol (ripe for tx) ```
87
What drug is used for prophylaxis against M. avium intracellulare?
Azithromycin
88
What 4 drugs are used for tx of M. avium inrtacellulare?
Azithromycin Rifampin Ethambutol Streptomycin
89
What is used for tx of tuberculoid leprosy? What is added for lepromatous?
Dapsone and rifampin | Clofazimine
90
What is the MOA of isoniazid?
Decreases the synthesis of mycolic acids | **Bacterial catalase peroxidase (KatG) is needed to convert INH to the active metabolite
91
What are the main SEs of isoniazid?
Neurotoxicity (prevent with vitamin B6) Lupus-like syndrome Hepatotoxicity
92
What is the MOA of rifampin?
Inhibits RNA-dep RNA polymerase
93
What is rifampin used for?
Tuberculosis Used with dapsone in leprosy to delay resistance Meningococal prophylaxis in contacts of children with H. inf type B
94
What are the four 4s of rifampin?
RNA polymerase inhibitor Revs up P450 Red/orange body fluids Rapid resistance if used alone
95
What are the SEs of rifampin
``` Minor hepatotoxicity (^P450) Orange body fluids ```
96
What is the MOA of pyrazinamide?
Uncertain--thought to acidify intracellular environment via conversion to pyrazinoic acid Effective in the acidic pH of phagolysosomes, where TB engulfed by macrophages is found
97
What is the use of pyrazinamide?
Mycobacterium tuberculosis
98
What are the two main toxicities of pyrazinamide?
Hyperuricemia | Hepatotoxicity
99
What is the MOA of ethambutol?
Decreases carbohydrate polymerization of the mycobacterium cell wall, blocking arabinosyltransferase
100
What is the toxicity of ethambutol?
Optic neuropathy (red-green color blindness)
101
Drug of choice for prophylaxis against meningococcal infection? In kids?
Ciprofloxacin | Rifampin
102
Drug for prophylaxis against gonorrhea
Ceftriaxone
103
Drug for prophylaxis against syphilis
Benzathine penicillin G
104
Drug for prophylaxis against recurrent UTIs
TMP-SMX
105
Drug for prophylaxis against endocarditis with surgical or dental procedures?
Penicillins
106
Drug for prophylaxis in pregnant women with group B strep
Ampicillin
107
Drug for prophylaxis against strep pharyngitis in child with prior rheumatic fever
Oral penicillin
108
Drug for prophylaxis against postsurgical S. aureus infection
Cefazolin
109
Drug for prophylaxis against gonococcal or chylamydial conjunctivitis in a newborn?
Erythromycin ointment
110
Drug for prophylaxis against Pneumoncystis pneumonia when CD4 <100/
TMP-SMX
111
Drug for prophylaxis against mycobacterium avium complex when CD4<50
Azithromycin
112
What is used for MRSA tx? VRE?
Vancomycin | Linezolid and streptogamins (quinupristin/dalfopristin)
113
What antifungal binds ergosterol and forms membrane pores that allow leakage of electrolytes?
Amphotericin B
114
What is amphotericin B used for?
Serious, systemic mycoses - Cryptococcus (ass flucytosine for meningitis) - Blastomyces - Coccidioides - Histoplasma - Candida - Mucor
115
Why should K and Mg be supplimented with Amphotericin B use?
Altered renal tubule permeability
116
When is Amphotericin B given intrathecally?
Fungal meningitis
117
What are the SEs of amphotericin B?
``` Fever/chills Hypotension Nephrotoxicity (hydration reduces) Arrhythmias Anemia IV phelbitis ```
118
What drug has the same MOA of amphotericin B but is only given topically because it is too toxic for systemic use?
Nystatin
119
What is nystatin used for?
Swish and swallow for thrush | Topical for diaper rash and vaginal candidiasis
120
What drug type inhibits ergosterol synthesis by inhibiting the P-450 enzyme that converts lanosterol to ergosterol?
Azoles: fluconazole, ketoconazole, clotrimazole, miconazole, itraconazole, voriconazole
121
What is fluconazole used for? Itrazonacole Clotrimazole and miconazole
Chronic suppression of cyptococcal meningitis in AIDS patients and candidal infections Blastomyces, coccidioides, histoplasma Topical fungal infections
122
What is the toxicity of azoles?
Testosterone synthesis inhibition (esp ketoconazole) | Liver dysfunction due to inhibition of P450
123
What is the MOA of flucytosine?
Cytosine deaminase converts it to 5-fluorouracil, which inhibits DNA and RNA biosynthesis
124
What is flucytosine used for?
Systemic fungal infections (with AmpB in cryptococcal meningitis)
125
What is the main tox of flucytosine?
Bone marrow suppression
126
What two drugs inhibit cell wall synthesis by inhibiting syn of beta glucan?
Caspofungin | Micafungin
127
What is the use for caspofungin and micafungin
Invasive aspergillosis | Candida
128
What is the toxicity of caspofungin and micafungin?
GI upset | Flushing (by histamine release)
129
What drug inhibits squalene epoxidase?
Terbinafine
130
What is terbinafine used for?
Treatment of dermatophytoses (esp onychomycosis)
131
What is the tox of terbinafine?
Abnormal LFTs | Visual distrubances
132
What drug interferes with microtubule function to disrupt mitosis in fungus? **deposits in keratin-containing tissues
Griseofulvin
133
What is the clinical use of Griseofulvin?
Oral tx of superficial infections; inhibits growth of dermatophytes
134
What is the toxicity of Griseofulvin
``` Teratogenic Carcinogenic Confusion Headaches Increases P450, warfarin metabolism ```
135
What drug is used for toxoplasmosis? Trypanosoma brusei T. cruzi Leishmaniasis
Pyrimethamine Suramin and melarsoprol Nifurtimox Sodium stibogluconate
136
What is the MOA of chloroquine?
Blocks the detoxification of heme into hemozoin | - Heme accumulates and is toxic to plasmodia
137
What is chloroquine used for?
Tx of plasmodial species aside from P. falciparum (has a membrane pump that decreases the IN concentration of the drug)
138
What is P. falciparum treated with?
Artemether.lumifantrine | Atrovaquone/proquanil
139
What is used for life-threatening malaria?
Quinidine | Artisunate
140
What is the toxicity of chloroquine (1)?
Retinopathy
141
What are some drugs that are used to immobilize helminths?
``` Mebendazole Pyrantel pamoate Ivermectin Diethylcarbamazine Praziquantel ```
142
What drug is used against flukes like Schistosoma?
Praziquantel
143
What two drugs inhibit influenza neuraminidase, decreasing the release of progeny viruses?
Zanamivir | Oseltamivir
144
What are zanamivir and oseltamivir used for?
Tx and prevention of influenza A and B
145
What drug inhibits the synthesis of guanine nucleotides by competitively inhibiting IMP dehydrogenase?
Ribavirin
146
What is ribavirin used for?
RSV | Chronic Hepatitis C
147
What are the SEs of ribavirin? (2)
Hemolytic anemia | Severe teratogen
148
What drug is monophosphorylated by thymidine kinase of HSV/VZV, and then phosphorylated twice more by cellular enzymes before inhibiting viral DNA polymerase by chain termination?
Acyclovir
149
What is acyclovir used for?
HSV and VZV
150
What is a prodrug of acyclovir that has better oral availability?
Valacyclovir
151
What drug is used for herpes zoster?
Famciclovir
152
What is the mechanism of resistance to acyclovir?
Mutated viral thymidine kinase
153
What drug is a guanisine analog that is 5'monophosphorylated by CMV viral kinase; 2 more phosphates added by cellular kinases Inhibits viral DNA polymerase
Ganciclovir
154
What is ganciclovir used for?
CMV; esp in immunocompromised patients
155
What is the toxicity of ganciclovir?
Leukopenia Neutropenia Thrombocytopenia Renal toxicity
156
Mechanism of resistance to ganciclovir?
Mutated CMV DNA polymerase or lack of viral kinase
157
What is a viral DNA polymerase inhibitor that binds to the PPi binding site of the enzyme and does NOT require activation by a viral kinase?
Foscarnet
158
What is the clinical use of foscarnet?
CMV retinitis in immunocompromised patients when ganciclovir fails Acyclovir-resistant HSV
159
What is the main toxicity of foscarnet?
Nephrotoxicity
160
What is the mechanism of resistance to foscarnet?
Mutated DNA polymerase
161
What is the MOA of cidofovir?
Inhibits viral DNA polymerase; doesn't require phosphorylation by viral kinase
162
What is the clinical use for cidofovir?
CMV retinitis in immunocompromised patients | Acyclovir-resistant HSV
163
What is the SEs of cidofovir? | What should cidofovir be administered with to prevent the SE?
Nephrotoxicity | Probenecid and IV saline to reduce toxicity
164
What kind of drug are: - Lopinavir - Atazanavir - Darunavir - Fosamprenavir - Saquinavir - Ritonavir - Indinavir
Protease inhibitors
165
What is the MOA of proteast inhibitors?
HIV-1 protease cleaves the polypeptide products of HIV mRNA into their functional parts Protease inhibitors prevent virus maturation
166
What is the role of the protease inhibitor ritonavir?
Boosts concentrations of other drugs by inhibiting P450
167
Toxicity of protease inhibitors
``` Hyperglycemia GI intolerence (N/D) Lipodystrophy (fat redistribution) Nephropathy Hematuria (indinavir) ```
168
Type of drug: - Tenofovir (TDF) - Emtricitabine (FTC) - Abacavir (ABC) - Lamivudine (3TC) - Zidovudine (ZDV,AZT) - Didanosine (ddl) - Stavudine (d4T)
NRTIs: competitively inhibit nucleotide binding to reverse transcriptase, cause chain termination
169
Which of the NRTIs is a nucleotide analog and does not require phosphorylation to be activated? (the rest are nucleoside analogs)
Tenofovir
170
What drug is used for general prophylaxis against HIV and for reduction of fetal transmission?
Zidovudine (ZDV or AZT)
171
What are the SEs of NRTIs?
``` Bone marrow suppression (reverse with G-CSF and epo) Peripheral neuropathy Lactic acidosis (nucleosides) Rash (non-nucleosides) Anemia (ZDV) ```
172
What are the NNRTIs? (3)
Nevirapine Efavirenz Delavirdine
173
What is the MOA of NNRTIs?
Bind RT at a site different from NRTIs | Don't require phosphorylation to be active
174
What is the MOA of raltegravir?
Integrate inhibitior--inhibits integration of the HIV genome into host chromosomes
175
What is the main SE of raltegravir?
Hypercholesterolemia
176
What are glycoproteins that are synthesized in virus infected cells that block replication of RNA and DNA viruses?
Interferons
177
What is IFN-alpha used for?
Chronic hepatitis B and C | Kaposi's sarcoma
178
What is IFN-beta used for?
MS
179
What is IFN-gamma used for?
NADPH oxidase deficiency
180
Toxicity of using IFNs
Neutropenia | Myopathy
181
What are the 8 antibiotics to avoid in pregnancy?
``` Sulfonamides Aminoglycosides Fluoroquinolones Clarithromycin Tetracyclines Ribavirin Griseofulvin Chloramphenicol SAFe Children Take Really Good Care ```
182
Using sulfonamides during pregnancy may cause:
Kernicterus
183
Using aminoglycosides during pregnancy may cause:
Ototoxicity
184
Using fluroquinolones during pregnancy may cause:
Cartilage damage
185
Using clarithromycin during pregnancy may be:
Embryotoxic
186
Using tetracyclines during pregnancy may cause:
Discolored teeth and inhibition of bone growth
187
Using ribavirin during pregnancy may be:
Teratogenic
188
Using griseofulvin during pregnancy may be:
Teratogenic
189
Using chloramphenicol during pregnancy may cause:
Gray baby :(

FirstAid:Microbiology (7 decks)

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