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Flashcards in Classifications of drugs and normal flora Deck (34):
1

3 primary ways to classify antimicrobial drugs

-susceptible organism
-MOA
-drug inhibits bacterial growth (bacteriostatic), or if it is lethal to cells (bacteriocidal)

2

Narrow vs. broad spectrum

narrow: active only against few microorganisms
broad: active against a wide variety

3

MOAs

Disruption of bacterial cell wall: penicillins, cephalosporins -> act to weaken cell wall and thereby promote cell lysis

inhibition of enzyme: sulfonamide drugs suppress bacterial growth by inhibiting enzyme required to produce folic acid from PABA.

Disruption of bacterial protein synthesis: disrupt function of bacterial ribosomes

Inhibition of bacterial nucleic acid synthesis

4

Inhibitors of cell wall synthesis

B-lactam abx: penicilllins, cephalosporins, carbapenems, monobactams

- clavulanic acid, sulbactam, taxobactam

5

Protein synthesis inhibitors: 30s subunit

Aminoglycosides: gentamicin, tobramycin, amikacin

Tetracyclines: tetracycline, doxycycline, minocycline

6

Protein synthesis inhibitors: 50s subunit

macrolides: erythromycin, clarithromycin, azithromycin

others: chloramphenicol, clindamycin, linezolid, streptogramins

7

DNA synthesis inhibitors

Fluoroquinolones: cipro, oflaxacin, norfloxacin, levofloxacin, gatiflocacin, moxifloxacin

Metronidazole

8

RNA synthesis inhibitors

Rifampin

9

Mycelia acid synthesis inhibitors

isoniazid

10

Folic acid synthesis inhibitors

sulfonamides, trimethoprim

11

Function of normal flora

GI tract: aids in digestion
mucous membranes: mucosal immunity
in general: protects host from colonization with pathogenic microbes

12

What are opportunistic pathogens?

cause disease when immune defenses are altered,
when they change their usual anatomic location
-the blood, brain, muscle and CSF are normally free of flora

13

Normal flora of the oral cavity

streptococci viridans
Lactobacilli
Staph (aureus and epidermidis)
corynebacterium sp.
bacteroides sp.
streptococcus sanguis
streptococcus mutans
actinomyces sp.

14

Normal flora of the nose

staphylococcus epidermidis
corynebacteria
staph aureus
Neisseria sp.*
Haemphilus sp*
strep pneumoniae*

15

Normal flora of the nasopharynx

non-hemolytic strep
alpha-hemolytic strep
Neisseria sp.
strep pneumoniae
strep pyogenes
H. influenzae
Neisseria meningitidis

16

Normal flora of lower resp. tract

usually sterile

individual becomes infected by the pathogen descending from the nasopharynx (H. influenzae, and S. pneumoniae)

17

Normal flora of external ear

staph epidermidis
staph aureus
corynebacterium sp.

18

Normal flora of GI tract

Enterobacteriaceae
enterococci
bacteroides
staph
lactobacilli
clostridia

19

Normal flora of GU tract

staph epidermidis
enterococcus faeccalis
Alpha-hemolytic strep
E coli
proteus
corynebaceria sp.
acinetobacter sp.
mycoplasma sp.
candida sp
mycobacterium smegmatis

20

Normal vaginal flora

corynebacterium sp.
staph
nonpyogenic strep (Group B)
E coli
lactobaciluus acidophilus
flavobacterium sp.
clostridium sp.
viridans strep
other enterobacteria

21

causative organisms of endocarditis and tx

native valve: sterp viridans -> Pen G or Amp+Nafcillin

IV drug user: MSSA, MRSA -> vanco

Prosthetic valve: S. epi, S. aureus, S. viridans -> vanco+rifampin+gentamicin

22

causative organisms of intra-abdominal infections

Diverticulitis, perirectal abscess, peritonitis-> E. coli, p. aeruginosa, enterococci

tx: TMP-SMX-DS or cipro, or levofloxacin+ metronidazole (outpt)

23

Skin and soft tissue causative agents

gen. cellulits: staph aureus, strep-> MSSA: cephalexin, MRSA: TMP-SMX-DS or clindamycin
strep: cephalexin

diabetic ulcer: staph, strep or pyogenes-> Doxy or TMP-SMX-DS or clindamycin

Animal bites -> cat: amox-clav (augmentin)

Necrotizing fasciitis: GABS, C. perfringens -> PCN G, cefoxitin, chloramphenicol, clindamycin, metronidazole

24

Urinary tract causative agents

E. coli, gram - aerobic bacilli, enterococcus, staph saprophyticus -> TMP-SMX-DS

if resistance is >20% to TMP -> use cipro, levo, moxi

25

Respiratory tract infections (pneumonias)

Aspiration pneumonia: anaerobic or aerobic -> clindamycin or ampicillin-sulbactam or A carbapenem

Lower/hosp acquired: pseudomonas aeruginosa, gram - aerobic bacilli -> imipenem -cilastatin or meropenem + cipro if suspect pseudo

Hx of HIV: pneuomocystis carinii, S. pneumoniae -> Trimethoprim-sulfamethoxazole (Bactrim, Septra)

26

Respiratory tract causative agents

sinusitis: S. pneumo, H. influenzae, M. catarrhalis, S. auerus, Grp A strep --> peds: amox or amox-clav, pcn allergy: clinda

adult: amox-clav, pcn allergy: levo or doxy

Community acquired pneumonia: all same as sinusitis plus klebsiella, mycoplasma, chlaymdia -> azithro, clarithro, doxycycline

27

meningitis in kids

child ampicillin + gentamicin

child 2 months - 12 years: strep pneuma, N. meningitis, H. influenza -> vanco + cerfriaxone

28

Meningitis

1 mo -> 50 years: S. pneumoniae, meningococci: cefotaxime or ceftriaxone+ vanco

amp+cefotaxime or gentamycin

29

Prophylactic antibiotics b/f surgery

should be admin. before surgery begins via IV
-often used to irrigate surgical site as well
- Cefazolon (Ancef) 30 minutes before incision

for pcn allergies: use vanco

30

who is at risk at developing endocarditis?

prosthetic heart valves
congenital heart disease

31

prophylaxis for endocarditis

30-60 minutes prior to dental procedures: amoxicillin 2 gm PO

if PCN allergy: clinda, azithro, clarithro

32

Complications of antibiotic therapy

toxicity
C. diff
alt of gut flora and change of Vit K levels leading to difficulty managing warfarin therapy
candida overgrowth
serious side effects

33

C diff diarrhea

can be life threatening, sever inflammation of colon, may lead to colectomy, highly contagious

34

Drugs most likely to cause C. diff

Most frequent:
Ampicillin/amoxicillin
cephalosporins
clindamycin
quinolones