571 - Antibiotics & Bacterial Disease

Nonpathogenic organisms adapted to grow on body surfaces of the host, forming part of the normal flora are known as

Commensals

1 multiple choice option

Which 2 commensal bacteria are normally found on the skin?

staph epidermidis

diptheroids

1 multiple choice option

What are the 3 functions of commensals?

-Digestive aids

-Prevents excessive overgrowth of dangerous bacteria

-Synthesis of essential metabolites

Microorganisms that do not usually produce disease in healthy individuals, but are implicated in human infections when the host is weak or compromised are known as

Opportunists

1 multiple choice option

Which two transient visitors of the throat are opportunists?

Strep pneumoniae

GAS

2 multiple choice options

Which two opportunists are normal residents of the GI tract?

E. coli

klebsiella

2 multiple choice options

Which microorganisms produce disease or tissue damage by their mere presence regardless of the condition of the host?

True pathogens

2 multiple choice options

What are some factors that allow bacteria to circumvent the immune response and contribute to the virulence of bacteria?

Capsules

Spores

Exotoxins/Endotoxins

Enzymes

Which 2 components are found in the cell envelope in gram (+) and gram (-) bacteria?

Cytoplasmic membrane

Cell wall

The cell wall is much thicker in gram (+) bacteria than gram (-) bacteria.

True

1 multiple choice option

The envelope of gram (-) bacteria has an outer membrane, not found in other types of bacteria.

True

1 multiple choice option

Because a cell wall is not found in higher organisms, anti-microbial drugs can inhibit its formation __________ host cells.

without harming

1 multiple choice option

Effectiveness of cell wall inhibitors is usually reduced by concurrent administration of

Bacteriostatic antibiotics

Abx exerts its killing effect as long as concentration remains above the minimum inhibitory concentration.

Interval dependent killing (time dependent killing)

1 multiple choice option

Abx continues to exert its killing effect after the concentration has fallen below the bacteria's minimum inhibitory concentration (post abx effect). The higher, the peak, the greater the killing effect.

Concentration dependent killing

1 multiple choice option

Which two antibiotics are interval independent killers?

vanco

B-lactams

Which two antibiotics are concentration dependent killers?

aminoglycosides

fluoroquinolones

Which gram (+) aerobe is the most virulent of the staph species and produces b-lactams like MSSA, which has no binding site?

staphylococcus aureus

B-lactams don't work against MRSA because it alters the penicillin binding protein.

True

1 multiple choice option

Which 3 deep tissue infections is caused by Staphylococcus?

-Osteomyelitis

-Bacterial pneumonia

-Endocarditis

What three diseases are caused by staphylococcal toxins?

-RItter's disease

-TSS

-staphylococcal food poisoning

Which gram (+) organism is responsible for upper respiratory infections such as pharyngitis, sinusitis and otitis media?

streptococcus

A pt presents to the clinic with impetigo, erysipelas, and wound/burn infections. What pathogen would you suspect cause this?

streptococcus

Which two enterococcal species (gram +) are categorized as VRSA/VRE due to their resistance to vanco?

E. faecalis

E. faceium

_____________ cannot thrive in the presence of oxygen as they do not contain enzymes to defend against oxygen.

Anaerobes

1 multiple choice option

Which type of anaerobes cause other effects; spore forming?

clostridia

Which bacteroides [gram (-)] anaerobe the most abundant of the lower GI tract and is a b-lactam producer?

B. fragilis

Which bacteroides is found in the oral cavity, upper respt tract, and human bites?

B. melaniogenicus

Most gram (-) aerobes are _____, or enterobacteriaceae.

rods

Which gram (-) aerobe is a part of the normal flora, yet also causes opportunistic infections, most commonly UTIs and also causes painful diarrhea?

E. coli

3 multiple choice options

Like E. coli, this gram (-) aerobe causes similar symptoms in addition to lower respiratory tract infections such as pneumonia.

Klebsiella pneumoniae

3 multiple choice options

Another common gram (-) aerobe that causes UTIs but is also becoming increasingly resistant to abx.

proteus mirabilis

3 multiple choice options

Which gram (-) aerobe is notorious for its multiple abx resistance mechanisms, making it extremely challenging to treat, and causes diseases such as pneumonia, burn wound infections, and UTI's?

pseudomonas aeruginosa

3 multiple choice options

ESBL (extended spectrum beta-lactamase) producers are typically seen in __________ microbes

gram (-)

1 multiple choice option

A type of bacterial resistance due to the production of an enzyme or chemical capable of destroying most b-lactam antibiotics are known as

ESBLs

Bacteria which produce ESBL's are part of the multi drug organisms known as

MDRO's (multi-drug resistant organisms)

ESBLs on 'steroids' are known as ___________ and are produced by klebsiella pneumonia

carbapenemases (KPC)

B-lactam drugs bind to a group of bacterial enzymes known as the _______

PBPs (PCN binding proteins)

What is responsible for the assembly, maintenance, and regulation of the peptidoglycan portion of the bacterial cell wall by creating a lattice meshwork which provides structure and stability?

PBPs

B-lactam drugs have low toxicity, and are safe enough to be given to children.

True

1 multiple choice option

Methicilin, the first abx used to treat staph, has been phased out as it is no longer effective and has shown to cause more harm than good.

True

1 multiple choice option

narrow spectrum penicillins

PCN G

PCN V

Penicillinase-resistant PCNs

oxacillin

cloxacillin

dicloxacillin

nafcillin

Which b-lactam drugs are a good treatment option for MSSA?

Penicillinase-resistant PCNs

Extended-spectrum PCNs

Amoxicillin

ampicillin

piperacillin

ticarcillin

Which two extended spectrum penicillins are effective against pseudomonas?

piperacillin

ticarcillin

Which abx are well known for drug-induced hypersensitivity reactions?

PCNs

True PCN allergy occurs only in _______ of pts who give a history of PCN allergy.

7-23%

Hypersensitivity reactions occur when penicillin is degraded to __________ and other compounds that combine with body proteins to form antigens that illicit antibody formation.

penicilloic acid

Aside from hypersensitivity reactions, PCNs are remarkably nontoxic to the human body and produce very few other adverse effects other than ________ fx, when the pt is already sick.

renal

PCNs can disturb the normal flora of the gut and produce diarrhea and super infections with penicillin resistant organisms, such as C diff, which can cause __________

pseudomembranous colitis

B-lactamase inhibitors (distractors) such as ___________ must be used in conjuction with B-lactams in order to be effective, as they are not active on their own.

clavulanic acid

sulbactam

tazobactam

Which B-lactamase inhibitor has little, if any, antimicrobial effects itself, but is used on beta lactamase producing microbes to tie up enzymes and is the only oral inhibitor and is usually paired with amoxicillin?

clavulanic acid

2 multiple choice options

Which B-lactamase inhibitor is used with ampicillin parenterally (IV only)?

sulbactam

2 multiple choice options

Which B-lactamase inhibitor is used with piperacillin and ticarcillin parenterally (IV only)?

tazobactam

2 multiple choice options

Which b-lactam drugs are one of the largest and most widely used groups of antibiotics and consists of five generations of semi synthetic drugs?

Cephalosporins

First generations of cephalosporins are primarily active against ________ and a few gram negative bacilli.

gram (+) cocci

Subsequent generations of cephalosporin have increased activity against __________ and less activity against some species of gram-positive cocci.

gram (-) bacilli

First generation cephalosporin, such as _________ have good activity against most gram + such as streptococci and MSSA.

Cephalexin (Keflex)

First generation cephalosporins, also cover a few gram (-) aerobe bacilli such as

E. coli

Klebsiella pneumonia

Second generation cephalosporin, such as ________________ have similar activity against gram (+) cocci with increased activity against gram (-) bacilli.

ceclor

cefzil

ceftin

Third generation cephalosporins such as ____________ have greater activity against a wider range of gram (-) organisms like enterobacteriaceae, H influenzae, and M catarrhalis.

Rocephin

Vantin

Cefepime (maxipime), the fourth generation is the only cephalosporin that will cover pseudomonas.

True

1 multiple choice option

1st generation cephalosporins are typically used to treat

UTI

mild skin/soft tissue infections

otitis media

upper + lower respiratory tract infections

Second generation cephalosporin are typically used to treat

Sinusitis

Otitis media

Lower respiratory tract infections

Third generation cephalosporins are typically used to treat

Meningitis

febrile neutropenia

Community acquired pneumonia

Fourth generation cephalosporins are typically used to treat

Meningitis

Febrile neutropenia

Pneumonia

nosocomial infections (hospital acquired)

5th generation cephalosporins are typically used to treat

extremely resistant infections (may require approval)

Which 1st generation cephalosporin is commonly used prior to surgery as a prophylactic and is given via IV?

cefazolin (ancef)

1 multiple choice option

Which 1st generation cephalosporin is most tolerated by peds and is given via po?

cephalexin (keflex)

1 multiple choice option

Which 2nd generation cephalosporin is given po and is known for its structure which leads to hypersensitive reactions?

cefaclor (ceclor)

1 multiple choice option

Which 2nd generation cephalosporin is given po and IV?

cefuroxime (ceftin)

1 multiple choice option

Which 3rd generation cephalosporin is given po and may cover pneumonia and upper respiratory infections?

cefdinir (omnicef)

2 multiple choice options

Which 3rd generation cephalosporin is given via IV AND is the only 3rd gen that covers pseudomonas?

ceftazidime (fortaz)

2 multiple choice options

Which 3rd generation cephalosporin is given via IV?

ceftriaxone (rocephin)

Which 5th generation cephalosporin is active against MRSA, pseudomonas, and enterococci?

ceftobiprole (zeftera)

Cephalosporins have an excellent safety record, although they can exhibit some cross-sensitivity with PCNs and about 5% of persons allergic to penicillin will also be allergic to cephalosporins.

True

1 multiple choice option

Monobactams such as Aztreonam (azactam) only covers gram (-) bacteria, therefore it can be really only be used against __________.

pseudomonas

_____________, 'snobs of the family', are bactericidal to a wide range of gram (+) and especially (-) bacilli infections and are the drugs of choice for ESBLs.

Carbapenems

Which drugs are stronger because of the change in chemical structure (5 sided ring vs 6 sided ring)

carbapenems

3 multiple choice options

Which carbapenem can be given IV or IM and are good for tissues, but does not cover pseudomonas?

ertapenem

3 multiple choice options

Which two carbapenems act as carbopenemase inhibitors and will distract the bacteria?

meropenem/vaborbactam (vabomere)

Which B-lactam drugs are used for endocarditis, pneumonia, UTIs, and skin + soft tissue infections?

carbapenems

2 multiple choice options

Which glycopeptide antibiotic is active against many gram (+) cocci & bacilli and is active against some strains of MRSA?

vanco

Penicllin-resistant organisms which cause endocarditis and necrotizing fasciitis can be treated with

vanco

In addition to treating streptococcal and enterococcal infections, which other strains is vanco effective against?

bacillus

clostridium

corynebacterium

Vanco is known for poor po absorption. Which infections would vanco actually be effective against if taken po?

GI C. diff

Pts with pneumonia, abcesses, and MRSA should be given vanco via which route?

IV

1 multiple choice option

If vanco is infused at an excessive rate, it can cause hypotension and an erythematous rash on the face and upper body known as the ___________ syndrome

red neck/red man

Which ribosome subunits are found in prokaryotes?

30S + 50S

1 multiple choice option

Which ribosome subunits are found in eukaryotes?

40S + 60S

1 multiple choice option

Which antibiotic binds to the 30S subunit where it interferes with the assembly of the functional ribosomal apparatus and can cause the reading of the genetic code so the wrong amino acid is inserted into the protein.

This irreversible effect leads to the death of the bacteria.

aminoglycosides

Which 3 aminoglycosides can be given IV or IM to treat systemic infections and is typically used together with B-lactams?

amikacin

gentamicin

tobramycin

Aminoglycosides are highly active against _______________ and are now the most commonly used agents worldwide.

aerobic, gram (-) bacilli

Although all aminoglycosides are effective against pseudomonas, ___________ is the most effective.

tobramycin

2 multiple choice options

Aminoglycosides are preferred over tetracyclines in tx for higher acuity pts.

True

1 multiple choice option

Which abx are broad-spectrum, bacteriostatic, and are 4 ringed anthracycline compounds?

tetracyclines

Which two tetracyclines are typically given orally?

doxy

minocycline

Which tetracycline is given via IV only?

tigecycline

2 multiple choice options

Unlike aminoglycosides, Tetracyclines ____________ bind to ribosomal subunits which prevents the addition of new amino acids to the growing peptide chain, accounting for their bacteriostatic action.

reversibly