Basic Bacteriology Flashcards
(143 cards)
1
Q
Don’t gram stain
A
Treponema, mycobacteria, mycoplasma, legionella (intracellular), rickettsia (intracellular), chlamydia (intracellular)
2
Q
Giemsa stain
A
Chlamydia, borrelia, rickettsia, trypanosomes, plasmodium
3
Q
PAS stain
A
Stains glycogen and mucopolysaccharides
4
Q
Ziehl-Neelsen/ carbon fuchsin stain
A
Acid fast bacteria and Protozoa
5
Q
India ink
A
Stains cryptococcus
6
Q
Silver stain
A
Stains fungi, legionella, h pylori
7
Q
Chocolate agar
A
Stains H. Flu
8
Q
Thayer-Martin stain
A
Stains Neisseria
9
Q
Bordet-Gengou/Regan-Lowe medium
A
Stains B. Pertussis
10
Q
Eaton agar
A
Stains M. Pneumo
11
Q
MacConkey agar
A
LF turn pink
12
Q
EMB agar
A
Stains E. coli
13
Q
Charcoal yeast extract
A
Stains legionella
14
Q
Sabouraud agar
A
Stains fungi
15
Q
Glycocalyx
A
Loose network of polysaccharides that mediates adherence to surfaces
16
Q
Intracellular bugs
A
Obligate: Rickettsia, Chlamydia, Coxiella (need host ATP)
Facultative: Salmonella, Neisseria, Brucella, Mycobacterium, Listeria, Francisella, Legionella, Yersinia pestis
17
Q
Encapsulated bacteria
A
Strep pneumo, H. flu, Neisseria meningiditis, E Coli, Salmonella, Klebsiella, Groub B strep (capsules = anti-phagocytic; asplenics are at increased risk)
18
Q
Urease-positive organisms
A
CHuck Norris hates PUNKSS:
Cryptococcus, H pylori, Proteus, Ureaplasma, Nocardia, Klebsiella, S. epidermidis, S. saprophyticus
19
Q
Catalase positive organisms
A
Cats Need PLACESS to hide:
Nocardia, Pseudomonas, Listeria, Aspergillus, Candida, E. coli, Staph, Serratia
Chronic granulomatous disease (NADPH oxidase deficiency) have recurrent infections with these guys.
20
Q
Pigment-producing bacteria
A
Actinomyces israelii (yellow granules), S. aureus (yellow), Pseudomonas (blue-green), Serratia marcescens (red)
21
Q
Bacterial virulence factors
A
Protein A - S. aureus, binds Fc region of IgG to prevent opsonization/phagocytosis
IgA protease - S. pneumo, H. flu, Nesseria - cleaves IgA to help colonize respiratory mucosa
M protein - Group A strep, prevents phagocytosis and may –> rheumatic fever
22
Q
Exotoxin location of genes
A
Plasmid or bacteriophage
23
Q
Endotoxin location of genes
A
Bacterial chromosome
24
Q
Bugs with exotoxins
A
Inhibit protein synthesis:
Corynebacterium diphtheriae, Pseudomonas aeruginosa (both inactivate elongation factor), Shigella and EHEC (Shiga and Shiga-like toxins, both increase cytokine –> HUS; Shiga also invades mucosa –> dysentery)
Increase fluid secretion:
ETEC (heat labile [increase cAMP] and heat-stable [increase cGMP] toxins –> watery diarrhea), Bacillus anthracis (edema toxin mimics AC), vibrio cholerae (overactivates AC by permanently activating Gs –> increased Cl- secretion in gut and rice-water diarrhea)
Inhibit phagocytic ability
B. pertussis (overactive AC by disabling Gi)
Inhibit release of neurotransmitter:
Clostridium - cleave SNARE (tetani prevents release of inhib NTs from Renshaw cells –> spasticity; botulinum inhibits ACh (stimulatory) –> flaccid paralysis
Lyse cell membranes: Clostridium (alpha toxin –> gas gangrene from degradation of phospholipids) and Streptococcus pyogenes (streptolysin O)
Superantigens –> shock (Staph aureus - TSST-1, Strep pyogenes - Exotoxin A) - via release of IL-1, IL-2, IFN-gamma, TNF-alpha
25
Role of endotoxin
LPS in G- --> activates macrophages, activates complement, activates tissue factor
26
Transformation
Bug can pick up naked DNA from environment
27
Conjugation
Bacterial sex (F+ plasmid contains genes for sex pilus and conjugation - meets up with F- and passes single strand plasmid DNA across conjugal bridge)
Can include some plasmid genes if F+ plasmid was incorporated into bacterial chromosome (Hfr)
28
Transposition
Segment of DNA that can jump from plasmid to chromosome and vice versa
29
Transduction
Phage infects bacterium and cleaves bacterial DNA (generalized - lytic phage) or incorporates its DNA into bacterial chromosome (lysogenic) and then when phage DNA is excised, takes some bacterial with it ("specialized transduction")
Lysogenic phase bacterial toxins:
Shiga-like, Botulinum, Cholera, Diphtheria, S. pyogenes
30
G+ lab algorithm
G+ = purple/blue
Catalase positive cocci = Staph --> Coag positive = aureus; Coag negative --> Novobiocin (sensitive = epidermidis, resistant = saprophyticus)
Catalase negative cocci = Strep --> hemolysis (alpha [green on blood agar] = pneumo [capsule, optochin sens, bile soluble] and viridans; beta [clear on blood agar] = pyogenes [bac sensitive], and agalactiae [bac res]; gamma = Group D (Enterococcus) vs. S. bovis)
31
Strep pyogenes
Group A strep!
Pyogenic sx (pharyngitis, cellulitis, impetigo, erysipelas)
Toxigenic sx (scarlet fever, TSS, necrotizing fasciitis)
Immuno sx (RF, acute GN)
Bacitracin sensitive, beta hemolytic, PYR+, M protein = virulence factor and Ig to it enhance host defenses but can also --> RF
32
ASO titer
Detect recent Strep pyogenes infection
33
JONES criteria
Criteria for acute RF (usually preceded by pharyngitis)
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Joints (polyarthritis)
Heart (carditis)
Nodules (subcut)
Erythema marginatum
Sydenham chorea
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34
Strep viridans
Alpha hemolytic, optochin res, normal flora of oropharynx
Can --> dental caries and subacute bacterial endocarditis at already damaged heart valves
35
Strep pneumo
G+ diplococci, encapsulated, optochin sensitive, alpha hemolytic
Sx = MOPS
36
Staph aureus
Inflamm sx (skin infections, pneumo, endocarditis, osteomyelitis)
Toxin-mediated sx (TSST-1, scalded skin syndrome, rapid-onset food poisoning)
MRSA
Coag positive, Catalase positive
37
Staph epidermidis
Catalase positive, Coag negative, novobiocin sensitive
Infect prosthetic devices (biofilm)
38
Staph saprophyticus
Catalase positive, Coag negative, Novobiocin resistant
Uncomplicated UTI in young women
39
Strep agalactiae
Group B strep
Bacitracin resistant, beta-hem, babies!
40
Group D strep
Enterococcus - UTI, biliary tract infxn, subacute endocarditis; VRE!
Strep bovis - colonizes gut, can --> bacteremia and subacute endocarditis, assoc with colon cancer
41
Cystine-tellurite agar
Grows corynebacterium diphtheriae
42
corynebacterium diphtheriae
Makes exotoxin that inhibits protein synthesis --> pseudomem pharyngitis with LAD, myocarditis and arrhythmias
Toxoid vaccine
43
Spore forming bacteria
Bacillus
Clostridium
Coxiella
44
C diff toxins
Toxin A: enterotoxin, binds brush border of gut
Toxin B: cytotoxin --> cytoskeletal disruption via actin depolymerization --> pseudomem colitis
Detect toxins in stool to diagnose
45
Anthrax
Bacillus anthracis = G+, spore-forming rod
Cutaneous: painless papule surrounded by vesicles --> black eschar
Pulmonary: inhale spores --> flu-like sx --> fever, pulmonary hemorrhage, mediastinitis, shock
46
Bacillus cereus
Spores (esp in reheated rice) --> enterotoxin ingestion --> food poisoning
47
Actinomyces vs. Nocardia ([an]aerobe? stain? sx? tx?)
Actinomyces = anaerobe; Nocardia = aerobe
A = gram pos; N = gram pos and weakly acid fast
A -> oral/facial abscesses that drain through sinuses, yellow "sulfur granules"
N -> pulmonary infections or cutaneous infxns following trauma in IC pts
Sulfonamides for Nocardia, Penicillin for Actinomyces (SNAP)
48
AIDS prophylaxis regimens with CD4 counts
- M. avium: prophylaxis with azithromycin when CD4+ count less than 50
- PCP: TMP-SMX, dapsone, atovaquone when CD4 less than 200
- Toxo: TMP-SMX, CD4
49
Gram negative lab algorithm
Gram stain --> pink = G-
Diplococci? Neisseria meng = maltose fermenter; N. gonorrhoeae = maltose non-fermenter
Rod-cocci = Haemophilus, Pasteurella, Brucella, Bordetella
Rods --> LF (Klebsiella, E Coli, Enterobacter); NLF --> oxidase positive (pseudomonas) vs. oxidase negative (Salmonella, Proteus, Yersinia [all produce H2S], Shigella)
50
Cause of Waterhouse-Friedrichsen syndrome
Neisseria meningiditis (adrenal failure due to hemorrhage)
51
Meningitis treatment (N.meng or H. flu)
Ceftriaxone; rifampin for prophylaxis in close contacts
- Vaccine for HiB now routine; vaccine for N.meng exists but not routine
52
Symptoms of H. flu
Epiglottitis (cherry red), Meng, Otitis media, Pneumo
Treat mucosal infxns with amox +/- clavulanate
53
Pseudomonas symptoms/disease associations
```
Pneumo (can be chronic in CF)
sepsis
otitis externa
UTIs
Drug use
Diabetes
Osteomyelitis (esp with puncture wounds, burns)
```
Also, ecthyma gangrenosum (rapidly progressive, necrotic cutaneous lesion caused by pseudomonas bacteremia, especially in IC pts)
54
E coli virulence factors
Fimbriae - cystitis and pyelo
K capsule - PNA, neonatal meng
LPS endotoxin - septic shock
55
Types of E Coli
EIEC - invasive dysentery --> necrosis and inflam
ETEC - traveler's diarrhea, no inflamm or invasion
EPEC - no toxin, adheres to apical surface and flattens villi --> no abs
EHEC/STEC - shiga-like toxin --> HUS (anemia, thrombocytopenia, renal failure due to microthrombi)
56
Klebsiella
Aspiration (DM and alcoholics) Lobar pneumo with currant jelly sputum
57
Campylobacter jejuni
Bloody diarrhea, esp in kids; fecal-oral transmission
Can --> guillan-barre and reactive arthritis
58
Typhoid fever
Caused by Salmonella typhi
Sx: rose spots on abdomen, constipation, ab pain, fever
Tx: ceftriaxone or fluoroquinolone
Oral vaccine = live/att; IM vaccine with capsular polysacch
59
Dysentery
Causes:
Campylobacter
Salmonella (not typhi) - makes H2S, found in poultry, eggs, pets
Shigella (makes shiga toxin, which is invasive, so low infectious dose, cell-to-cell (not hematogenous) spread)
Entamoeba histolytica (amebiasis - cysts in water, can also get liver abscess)
60
Vibrio cholerae mechanism of action
Enterotoxin permanently activates Gs --> increased cAMP --> watery diarrhea
61
Pseudoappendicitis
Caused by yersinia enterocolitica (right lower ab pain due to mesenteric adenitis or terminal ileitis)
Pet feces, contaminated milk
62
H. pylori diagnosis and treatment
Diagnosis: urea breath test (catalase, oxidase, and urease +) or fecal antigen test
Tx: PPI, clarithro, amoxicillin
63
Stages of syphilis
Primary - painless chancre
Secondary - disseminated disease, maculopapular rash (ON HANDS AND SOLES), condyloma lata
Tertiary - gummas, aortitis, Argyll Robertson pupil (accomodates but doesn't react to light), neuro sx (general paresis/ataxia)
VDRL/RPR positive (nonspecific) --> confirm with FTA-Abs
64
Congenital syphilis sx and prevention
Snuffles, saddle nose, notched teeth, facial abnormalities (linear scars), mulberry molars, short maxilla, saber shins
Treat mom early in preg!
65
VDRL false positives
VDRL:
Viral infection
Drugs
RF
Lupus and leprosy
66
Jarisch-Herxheimer reaction
Flu-like syndrome after abx are started --> kill some bugs (usu spirochetes) that release endotoxin
67
Pasteurella multocida
Animal bite
Cellulitis, osteomyelitis
68
Rickettsia types and transmission
Prowazekii - epidemic typhus, louse
Rickettsii - RMSF, dermacentor (dog tick) - rash starts at wrists and ankles
Typhi - endemic typhus, fleas
typhus: rash starts on trunk
69
Clue cells
Vaginal epithelial cells covered with Gardnerella bacteria ("stippled")
fishy smell to discharge, nonpainful
70
Rashes
Syphilis - hands and soles
R. rickettsii (RMSF) - wrists and ankles
R. typhi/prowazekii - central rash (spares palms and soles)
Coxsackie A (hand, foot, and mouth dz) - palms and soles
Measles - starts at head/neck and spreads downward; Koplik spots in mouth
Rubella - pink macules beginning at head and moving down --> desquamation
Roseola - rose-colored macules several days after fever
Parvo B19 - slapped cheek rash on face
VZV/Chickenpox - vesicular rash begins on trunk and spreads to extremities
71
Ehrlichiosis (dz + histo) vs. Anaplasmosis (dz + histo)
Ehrlichia, vector is tick
Histo: monocytes with morulae in cytoplasm
Anaplasma, vector is tick
Histo: granulocytes with morulae in cytoplasm
72
Chlamydia (types + tx)
Trachomatis - reactive arthritis (Reiter syndrome), follicular conjunctivitis, nongonococcal urethritis, PID
- Serotype A,B,C - chronic infxn in Africa (can --> blindness)
- Serotype D-K - urethritis/PID, ectopic preg, neonatal pna with eosinophilia, neonatal conjunctivitis
- Serotypes L1-3: lymphogranuloma venereum (small, painless ulcers on genitals --> swollen, painful ln)
Pneumo/psittaci - atypical PNA, aerosol transmission
Tx: Azithro
73
Atypical PNA
Mycoplasma pneumo
Chlamydia
Treat with doxy
74
Systemic mycoses
Histo (Mississipi, Ohio River) -- pneumo, fills macrophages
Blasto (east of histo) --> inflamm lung dz, granulomatous nodules, ~size of RBC
Coccidioidomycosis - SW --> PNA a nd meng, spherules filled with endospores bigger than RBC
Paracoccidioidomycosis - Latin America - budding yeast looks like "captain's wheel"
75
Opportunistic mycoses
- Candida albicans (thrush in IC, vulvovaginitis in DM or with abx, diaper rash, endocarditis in IVDU, chronic mucocut candidiasis)
- Aspergillus fumigatus (ABPA, aspergillomas, aflatoxins; dz esp in IC and those with chronic granulomatous disease), branch at acute angles
- Cryptococcus (meng, cryptococcosis) - in soil and pigeon droppings, stain with India Ink, see "soap bubble" lesions in brain
- Mucor/Rhizopus (mucormycosis, esp in ketoacidotic DM and/or neutropenic pts) - fungi grow in vv and penetrate crib plate
- Pneumocystis jirovecii --> PCP (diffuse interstitial PNA with ground glass appearance on CXR), esp in IC pts, diag by lavage or bx; stain with silver stain
- Sporothrix schenckii --> Sporotrichosis; yeast spores introduced via trauma (eg rose thorn) --> local ulcer with nodules along draining lymphatics; can be disseminated in IC; treat with KI or itraconazole
76
Protozoa - GI
Giardia (steatorrhea)
Entamoeba histolytica (anchovy paste, liver abscess, dysentery)
Cryptosporidium (severe diarrhea in AIDS)
77
Protozoa - CNS infections
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Toxoplasma gondii (ring-enhancing lesions on CT/MRI, esp in AIDS reactivation) - cysts in meat, cat feces
Naegleria fowleri
Trypanosoma brucei (African sleeping sickness - ant variation --> recurring fevers; treat with melarsoprol and re
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78
Intestinal Nematodes/Roundworms
Treat with bendazoles
EAT:
Enterobius vermicularis/pinworm - tape test
Ascaris lumbricoides (roundworm)
Trichinella spiralis (undercooked meat)
Larvae penetrate skin --> coughed to lungs:
Strongyloides stercoralis
Ancylostoma duodenale (hookworm) - anemia
Necator (hookworm) - anemia
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Tissue nematodes (roundworms)
- Onchocerca (blackfly - river blindness)
- Loa loa (deer, horse, or mango fly; worm in conjunctiva and skin swelling)
- Wucheraria bancrofti (mosquito - elephantiasis from worm in lymphatics)
- Toxocara canis (fecal-oral; larva migrans)
Tx: diethylcarbamazine (ivermectin for onchocerca)
80
Cestodes (tapeworms)
- Taenia (ingest larvae for intestinal form, eggs for cysticerc)
- Diphyllobothrium latum (fish, B12 def)
- Echinococcus granulosus (dog feces, hydatid cysts in liver)
Tx: praziquantel; albendazole for echinococcus
81
Schistosoma
Tx: praziquantel
Schistosoma (snail = host; S.mansoni, S. haematobium (SCCA of bladder + pulm HTN)
Clonorchis (from fish, biliary tract inflamm, cholangiocarcinoma)
82
DNA viruses
- Herpesviruses (1 = oral, 2 = genital, 3 = VZV, 4 = EBV [mono, Burkitt, HL, nasopharyngeal ca; infects B cells and atypical lymphos on smear = reactive T cell; Monospot +], 5 = CMV (AIDS retinitis, PNA; monospot -, owl eye inclusions in infected cells), 6 = roseola, 8 = Kaposi sarcoma); Tzanck test = smear of opened skin vesicle to diagnose, or viral culture for skin/genitalia
- Hepadnavirus (HBV), has reverse transcriptase
- Adenovirus (febrile pharyngitis, acute hemorrhagic cystitis, PNA, conjunctivitis)
- Parvo (B19 - "slapped cheeks" of Erythema Infectiosum/fifth dz, aplastic crisis in SCD, RBC destruction (hydrops fetalis in fetus)) - SINGLE STRANDED
- Papilloma - HPV (16,18 -- cervical cancer)
- Polyoma (JC - progressive multifocal leukoencephalopathy in HIV, BK - kidney in transplant pts)
- Poxvirus (smallpox, cowpox, molluscum contagiosum)
83
RNA viruses
Reovirus - DS - coltivirus (Colorado tick fever) and rotavirus
Single Strand +:
Picorna
- Poliovirus
- Echo (aseptic meng)
- Rhino (common cold)
- Coxsackie (A = hand,foot,mouth; B = pleurodynia, myocarditis)
- Hep A
Hepevirus
Calicivirus (noro)
Flaviviruses (HCV, Yellow fever, Dengue, St. Louis encephalitis, WNV)
Togaviruses (Rubella, EEE/WEE)
Retroviruses (HTLV, HIV)
Coronaviruses (common cold + SARS)
SS -:
Orthomyxo (flu)
Paramyxo (Parainfluenza - croup, RSV - bronchiolitis in babies, Measles/Rubeola - cough, coryza, conjunctivitis, Mumps) - all have surface F protein that --> fusion of resp epith cells into multinucleated cells
Rhabdoviruses (Rabies)
Filoviruses (Ebola/Marburg)
Arena (LCMV, Lassa Fever)
Bunya (California encephalitis, Hantavirus, Rift valley fevers)
Delta (only replicates in presence of Hep B)
84
Genetic drift vs shift
Drift - small changes based on random mutations in HA (entry) of NA (exit) genes --> EPIDEMICS
Shift - Reassortment of viral genome sequences --> major changes in virus (eg flus) and PANDEMICS
85
Congenital infections
TORCHES
Toxoplasma - chorioretinitis, hydrocephalus, intracranial calcifications
Rubella - "blueberry muffin rash" (extramedullary hematopoeisis)
CMV - ventricular calcifications, rash, ID
HIV
Syphilis (facial abnormalities/scars, saddle nose, "snuffles," notched teeth, short maxilla, mulberry molars, saber shins, deafness
86
Rabies virus
Bullet-shaped
Negri bodies in Purkinje cells of CBL and HC
Long incubation post-exposure, travels to CNS by binding ACh receptors and then migrating retrograde up nerve axons
Sx: fever, malaise --> agitation, photophobia, hydrophobia, hypersalivation --> paralysis and coma --> death
87
Hepatitis D virus
RNA delta virus
Needs Hep B virus:
- Superinfection (HDV after HBV) - short incubation
- Coinfection (HDV with HBV) - long incubation
88
Hepatitis E virus
Fecal oral transmission, esp waterborne
RNA hepevirus
Short incubation, no cancer risk
High mortality in pregnant women
89
ALT vs AST in viral vs. alcoholic hepatitis
Viral: ALT > AST
Alcoholic: AST > ALT
90
Hepatitis B markers
HBsAg - surface, indicates hep B infection
Anti-HBs - indicates immunity to Hep B
HBcAg - core antigen
Anti-HBc - indicates infection, may be only positive marker during window period b/w acute disease and convalescence
HBeAg - core antigen, indicates active replication and thus high transmissibility
Anti-HBe - low transmissibility
91
HIV genes
env (gp120 - attach to host CD4 T cells; gp41 - fusion and entry)
gag (p24) - capsid protein
pol - reverse transcriptase
92
HIV entry into cell
Binds CD4 + coreceptor (CCR5 on macrophages in early disease, CXCR4 on T cells in later disease)
- CCR5 mutation --> decreased susc to HIV
93
HIV diagnosis
ELISA (high sensitivity); positive result --> Western blot (more specific)
94
Viral load tests in HIV
Prognostic
AIDS when
95
HIV diseases with CD4 counts
96
Atypical pneumonias
Mycoplasma
Legionella
Chlamydia
97
Bugs that cause osteomyelitis in sickle cell disease
Salmonella, Staph aureus
98
Three vaginal infections and their differences in inflammation, discharge, histo
Bacterial vaginosis - no inflamm, thin/white discharge with fishy odor, clue cells, high pH
Trichomoniasis (protozoan) - strawberry cervix, grey/green/foul-smelling discharge, motile trichomonads, elevated pH
Candida - inflammation, thick/white/cottage cheese discharge; can see pseudohyphae on slide, normal pH
99
ToRCHHeS
Toxo - chorioretinits, hydrocephalus and intracranial calcifications
Rubella - PDA, cataracts, deafness
CMV - hearing loss, seizures, periventricular calcifications, petechial rash
HIV - chronic diarrhea, recurrent infxns
Herpes simplex 2 - encephalitis, herpetic lesions
Syphilis - hydrops fetalis; if survives --> facial abnormalities, deafness, saber shins etc
Also Parvo B19 --> hydrops fetalis
100
Penicillinase resistant penicillins
Dicloxacillin, nafcillin, oxacillin
Narrow spectrum
Bulky R group --> resistance to beta lactamase
Used for staph aureus (not MRSA)
101
Aminopenicillins
Amoxicillin, ampicillin
- extended spectrum PCN (HHELPSS) + enterococci:
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H. flu
H. pylori
E. coli
Listeria
Proteus
Salmonella
Shigella
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102
Abx that block cell wall synthesis
Penicillin
Cephalosporins
Carbapenems
Monobactams
103
Abx that block folic acid synthesis
Sulfonamides - inhibit folate synthesis by mimicking PABA that inhibit dihydropteroate synthase (Dapsone = closely related - treats lepromatous leprosy); tx for G+, G-, Nocardia, Chlamydia;; can --> hemolysis if G6PD deficient, nephrotox, photosensitivity, kernicturus; res = altered enzyme, decreased uptake, increased PABA synth
Trimethoprim - inhibit dihydrofolate reductase; used with sulfonamides (synergy) for UTIs, Shigella, Salmonella, PJP treatment and prophylaxis, toxo prophylaxis; can --> megalo anemia, leukopenia, granulocytopenia (give folate supplement)
104
Abx that block DNA topoisomerase
Fluroquinolones - "flox"
Don't take with antacids!
treat GNR, Neisseria
tox: GI upset, superinfxns, skin rashes, headaches, dizziness; contraind: preg, nursing, kids (may damage cartilage, prolong QT), old people/people on steroids (tendonitis or tendon rupture)
res: mutated target (DNA gyrase), efflux pumps
105
Abx that damage DNA
Metronidazole
- used for GET GAP (anaerobes below the diaphragm)
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Giardia
Entamoeba
Trichomonas
Gardnerella vaginalis
Anaerobes
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- can --> disulfiram-like rxn (severe flushing, tachy, hypotension) with alcohol
106
Antibiotics that block RNA synthesis
Rifampin
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Antibiotics that block protein synthesis
50S subunit:
chloramphenicol - inhibit peptidyl transferase, used for meng, RMSF but toxic (aplastic anemia and gray baby; res = plasmid-encoded acetyltransferase inactivates drug)
macrolides - "ithromycin" - block peptide transfer/translocation; treat atypical pneumonias, chlamydia, B pertussis; can case arrythmia (increased QT), GI issues, cholestatic hep, rash, eosinophilia; inhibit cyt C; res: methylation of rRNA binding site so drug can't bind
streptogramin
clindamycin (blocks peptide transfer)
linezolid (prevents formation of initation complex, G+, inc VRE and MRSA; can --> bone marrow supp, peripheral neuropathy; res = point mutation of rRNA)
30S subunit:
- aminoglycosides (inhibit init complex formation); "-micin" + "kacin" - require O2 so ineffective against anaerobes, use for GNR; res = bacterial enzymes inactivate drug; can --> nephrotox, ototox, teratogenic
TCN (inhibit A site t-rna binding, accum intracellularly so good for rickettsia and chlamydia, also borrelia and mycoplasma; can --> GI distress, tooth discoloration, decreased bone growth; resistance = decreased uptake or increased efflux by plasmid-encoded transport proteins)
108
Cephalosporins
First gen: PEcK
Proteus
E coli
Klebsiella
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Second gen: HENPEcKS
H. flu
Enterobacter
Neisseria
Proteus
E coli
Klebsiella
Serratia marcescens
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Third gen: ceftriaxone, cefotaxime etc
Fourth gen: cefepime (gram neg, esp pseudomonas)
Fifth gen: ceftaroline (broad, inc MRSA, no pseudomonas)
109
Carbapenems
Broad spectrum, beta lactamase resistant
Administer with cilastatin to inhibit renal metabolism
Lots of side effects (CNS toxicity)
- For gram pos cocci, GNR, anaerobes
110
Monobactam
Aztreonam
Beta lactamase resistant
Treats GNR only
No cross allergy with PCN
111
Vancomycin
Inhibits cell wall peptidoglycan by binding D-ala-D-ala (not susc to beta lactamases, but yes to AA modification to D-ala-D-lac
- May --> nephrotox, ototox, flushing (red man syndrome - give antihistamines and slow infusion to prevent)
- Treats G+ only!!
112
Daptomycin
- lipopeptide (disrupts cell membrane)
- used for GPC, esp Staph aureus
- can --> myopathy, rhabdo
113
Rifamycins
Rifampin - TB (prophylaxis + tx - induces cyt P450)
Rifabutin - MAC proph/tx
Res: mut decrease drug binding to RNA pol (develops fast)
114
Kat G
Encodes Bacterial catalase-peroxidase that's needed to convert isoniazid to active metabolite (used for proph and treatment of TB)
115
Ethambutol
Decreased carb polymerization of mycobacterium cell wall by blocking arabinosyltransferase
Can --> optic neuropathy
116
Prophylaxis for endocard/dental procedures
Amoxicillin
117
Prevention of gonococcal conjunctivitis in newborns
Erythromycin ointment
118
Prevention of post-surgical infection with Staph aureus
Cefazolin
119
Prophylaxis of strep (in child with prior RF or pregnant woman)
Penicillin
120
Amphotericin B mechanism
Binds ergosterol in fungal membrane and makes pores to allow leakage of electrolytes
Keep hydrated to decrease nephrotoxicity, supplement with K and Mg
For serious, systemic mycoses
Class: polyene (also nystatin - too toxic for systemic use; eg "swish and swallow" for thrush)
121
Azole mechanism
Inhibit cyt P450 that converts lanosterol to ergosterol (some off target --> inhibition of host cytochrome P450, also testosterone synth inhibition)
122
Terbinafine mechanism
Inhibits fungal squalen epoxidase - used for dermatophytoses (esp oncychomycosis)
123
Echinocandin mechanism
Inhibit cell wall synthesis in fungi
Used for invasive aspergillosis and candida
"-fungin"
124
Griseofulvin mechanism
Interferes with MT function --> disruption of mitosis
Treats superficial fungal infxns (eg dermatophytes)
Teratogenic and carcinogenic, induces cyt P450
125
Nifurtimox - used to treat ____?
T. cruzi treatment
126
Pyrimethamine - used to treat ____?
Toxo
127
Suramin and melarsoprol - used to treat ____?
T. brucei
128
Stibogluconate - used to treat ____?
Leishmaniasis
129
HIV life cycle and antivirals' mechanisms at each step
1. Fusion - Maraviroc (binds CCR5 - inhibits interaction with gp120) prevents attachment; Enfuvirtide prevents penetration (binds gp41)
2. Uncoating and reverse transcription - blocked by NRTIs [all nucleosides except tenofovir, so need to be phosphorylated to be active --> chain term; ZDV (zidovudine/AZT) used for proph and to decrease fetal transmission)and NNRTIs (different binding site from NRTIs, don't need phosphorylation, may --> rash and hepatotox)
3. DNA integration - blocked by integrase inhibitors ("-gravir") - increase Cr kinase
4. transcription
5. Translation
6. Proteolytic processing - blocked by protease inhibitors ("-navir")
7. Packaging and assembly --> budding --> release
Standard regimen = 2 NRTI + 1 NNRTI or 1 protease inhibitor or 1 integrase inhibitor
130
Virus life cycles (general) with antiviral mechanisms at each step
1. Binding to host cell and endocytosis - blocked by interferon-alpha, which inhibits production of receptor proteins in host (HBV, HCV)
2. Uncoating - blocked by amantadine and rimantadine (no longer used for flu b/c of resistance)
3. Nucleic acid synthesis (blocked by guanosine analogs - acyclovir [HSV, VZV], ganciclovir [CMV], famciclovir [zoster], only phosphorylated and thus fxal in viral cells (res when this kinase is mutated), can --> kidney pbs if pt isn't adequately hydrated; viral DNA/RNA pol inhibitors - Cidofovir (nephrotox), Foscarnet [HSV, CMV], res via mutated polymerase; Guanine nucleotide synthesis - Ribavirin [RSV, HCV]
4. Virion assembly
5. Release of progeny - inhibited by neuraminidase inhibitors (oseltamivir, Zanamivir - used for flu)
131
Hep C drugs
Ribavirin (inhibits syntehsis of guanine) - teratogen!
Simeprevir (protease inhib) - don't use as monotherapy! can --> photosens
Sofosbuvir (RNA pol inhibitor) - don't use as monotherapy!
132
Abx to avoid in preg
```
Sulfonamides - kernicterus
Aminoglycosides - ototox
Fluoroquinolones - cartilage damage
Clarithromycin - embryotoxic
TCN - teeth, bone growth
Ribavirin - teratogen
Griseofulvin - teratogen
Chloramphenicol - gray baby (lack liver enzyme to metabolize it)
```
SAFe Children Take Really Good Care
133
Treatment for local infection with systemic mycoses?
systemic infection?
local = fluconazole or itraconazole
system = "big guns" - aka amphotericin B
134
Bugs causing brain abscess most commonly
Strep viridans, Staph aureus
if after dental procedure, oral anaerobes
135
Common causes of meng in newborn? children? adults? elderly?
newborn: GBS, E Coli, Listeria
Kids: Strep pneumo, N meng, HiB, enteroviruses
Adults: Strep pneumo, N. meng, Enteroviruses, HSV2 (1 = encephalitis)
Elderly: Strep pneumo, GNR, Listeria
136
Common causes of pna - in neonates, kids, adults, elderly
Neonates: GBS, E coli
Kids: viruses (eg RSV), mycoplasma, Chlamydophila, Strep pneumo
Adults (
137
Amoebas with ingested RBC
Entamoeba
sx = bloody diarrhea, abd cramps, pus in stool, RUQ pain and liver abscesses
tx =metronidazole, iodoquinol
138
Acid-fast cysts in the stool
Crypto (cysts in water --> diarrhea), Toxo (cysts in raw meat or cat feces)
139
Macrophages containing amastigotes
Leishmania donovani (transmitted by sandfly)
sx = HSM, malaise, anemia, weight loss
140
Tear-shaped trophozoites with two nuclei in stool
Giardia
sx = bloating, flatulence, nonbloody diarrhea, steatorrhea
transmitted via cysts in water
141
Myelin basic protein
may be present in CSF with demyelination (eg with PML from JC virus reactivation)
diag: bx or PCR for JC virus in CSF
142
protein and glucose in bacterial meng
protein elevated, glucose normal
143
CMV encephalitis vs PML
CMV - more systemic sx; histo: giant cells with eosinophilic inclusions; enhanicing periventricular WM lesions
PML: nonenhancing T2-hyperintense lesions
