Antibiotics and Antifungal Flashcards
Gram positive
stain purple; thick cell wall and thick outer capsule
Gram negative
stain red; more complex cell wall with a small capsule
with two cell membranes; an outer and inner membrane
- more difficult to treat because drug molecules have
a harder time penetrating the more complex cell wall of gram negative organisms.
Empiric therapy
treatment of an infection before
specific culture information has been reported or
obtained
Antibiotics
used to treat bacterial infections
Definitive therapy
antibiotic therapy tailored to treat
organism identified with cultures
Prophylactic therapy
treatment with antibiotics to
prevent an infection, as in intra-abdominal surgery or
after trauma
Subtherapeutic response
Signs and symptoms of infection do not improve.
Superinfection
can occur when antibiotics reduce or completely eliminate the normal bacterial and fungal flora that are needed to maintain normal function in various organs
i.e. vaginal or pharyngeal
Candida albicans yeast infections or antibiotics acquired diarrhea
becomes a serious superinfection when it causes antibiotic-acquired
colitis, pseudomembranous colitis or C. difficile infection; most common signs are odorous watery diarrhea, abdominal pain and fever.
Secondary infection
when another type of
superinfection occurs when a second infection closely follows the initial infection and comes from an external source (as opposed to normal body flora). Example: cough, colds and sore throat are usually viral; if
fever develops suspect bacterial secondary infection i.e viral pneumonia becomes bacterial pneumonia.
Most common severe reactions from antibiotic allergy
difficulty breathing; flushing, tachycardia, itching, anxiety
significant rash, hives, or other skin reaction; and
severe gastrointestinal (GI) intolerance
Bactericidal
kill bacteria
Bacteriostatic
inhibit growth of susceptible
bacteria rather than killing them immediately;
eventually leads to bacterial death
B- lactamase enzyme
- B-lactamase is one way a bacteria can fend off the effects
of antibiotic - can inactivate the antibiotic molecules by opening
the B-lactam ring (a structural component of the pcn molecule)
Sulfonamides
- One of the first groups of antibiotics
- Often combined with another antibiotic
- Combination of 2 drugs i.e. Sulfa combined with trimethoprim causes a
synergetic effect (stronger effect).
Sulfonamides:
Mechanism of Action
- Bacteriostatic (inhibits the growth of bacteria: does not destroy
the bacteria but inhibits their growth) - Prevent bacterial synthesis of folic acid (B-complex vitamin) required for synthesis of purines and nucleic acid (DNA & RNA)
- Only affect organisms that synthesize their own folic
acid
Sulfonamides: Indications
-Gram-positive and negative bacteria;
- Treatment of urinary tract infections; pneumonia; URI
Sulfonamides:
Adverse Effects
Common allergic reactions including photophobia and skin rash;
Hemolytic and aplastic
anemia, agranulocytosis,
thrombocytopenia
Superinfection
Convulsions, crystalluria
toxic nephrosis, headache,
neuritis, urticaria, cough
ß- Lactam
- Penicillins
- Cephalosporins
- Carbapenems
- Monobactams
Penicillin
B-Lactams
penicillin V or G cloxacillin
amoxicillin
ampicillin
piperacillin/
tazobactam
Penicillins: Mechanism of Action
Bactericidal
Enter the bacteria via the cell wall then bind to penicillin-binding protein.
Broad spectrum
* Penicillins do not kill other cells in the body.
Penicillins: Indications
Gram-positive and negative; Health care-acquired infections, including pneumonias, intra-abdominal infections and sepsis.
Penicillins: Contraindications and
Concerns
- Usually safe and well-tolerated medications
- Contraindications
- Known medication allergy (An allergic reaction to penicillin may also have an allergic reaction to other B- Lactam antibiotics.)
Penicillins: Adverse Effects
Nausea, vomiting, diarrhea, abdominal pain
Superinfection
IV penicillin’s are irritating to the veins and contain high amounts of
sodium or potassium. High doses may cause seizures.
Penicillins: Interactions
- Nonsteroidal anti-inflammatory drugs
- Oral contraceptives
- warfarin
- Others/MANY
Cephalosporin
B-Lactams
* Semisynthetic antibiotics
* Structurally and pharmacologically related
to penicillins
* Bactericidal action
* Broad spectrum
* Divided into groups according to their antimicrobial activity
- Depending on generation, these drugs may be active against gram-
positive, gram-negative or anaerobic bacteria. They are not active against fungi and viruses.
Cephalosporins:
First Generation used for
surgical prophylaxis and for susceptible staphylococcal infections - such as staph infection of the skin
Cephalosporins:
Second Generation
Better gram-negative coverage than first- generation
cephalosporins
cefoxitin:
* Used prophylactically for abdominal or colorectal surgeries
* Also kills anaerobes
cefuroxime:
* Surgical prophylaxis
* Does not kill anaerobes
Cephalosporins:
Third Generation
Most potent group against gram-negative bacteria
Less active against gram-positive bacteria
Examples
* cefotaxime sodium
* cefixime
* cefpodoxime proxetil
* ceftizoxime
* ceftazidime
* ceftriaxone
Cephalosporins: 3rd Gen
ceftriaxone sodium
IV and IM, long half-life, once-a-day dosing
* Elimination is primarily hepatic
* Easily passes meninges and diffused into cerebrospinal fluid
to treat central nervous system infections
Cephalosporins:
Third Generation
ceftazidime
- IV and IM forms
- Excellent gram-negative coverage
- Used for difficult-to-treat organisms such as Pseudomonas
spp. - Excellent spectrum of coverage
- Resistance is limiting usefulness.
Cephalosporins:
Fourth Generation
- Broader spectrum of antibacterial activity than third-
generation cephalosporins, especially against gram-
positive bacteria - Uncomplicated and complicated urinary tract
infection
Cephalosporins:
Adverse Effects
Mild diarrhea, abdominal cramps, rash, pruritus, redness, edema
Superinfection
Penicillin cross- sensitivity; Incidence between 1 and 4%.
Carbapenem
B-Lactams
* Broadest antibacterial action of any antibiotics to
date
Cross sensitivity to PCN; Must be infused over 60 minutes
Carbapenem Action
Bactericidal ( gram + and gram-)
Binds to penicillin-binding proteins inside bacteria, which in turn inhibits bacterial cell wall synthesis.
Carbapenem Uses
Reserved for complicated body infections; treatment of severe or high-risk bacterial infections such as multidrug-resistant (MDR) bacterial infections i.e. MRSA
Carbapenem
imipenem/cilastatin (Primaxin®)
- Used for treatment of bone, joint, skin, and soft tissue
infections; many other uses - Cilastatin inhibits an enzyme that breaks down imipenem.
Carbapenem Adverse effects
most serious adverse effect is seizures; 1.5% for <500mg q 6hrs and 10% > 500mg q 6hrs
Superinfection
Monobactams
4th category of B-lactams
* Primarily active against aerobic gram-negative bacteria (E.
coli, Klebsiella spp., Pseudomonas spp.)
* Bactericidal
* Used for management of cystic fibrosis patients with
chronic pulmonary Pseudomonas aeruginosa infections
Macrolides
- erythromycin (E-Mycin®, many others)
- azithromycin (Zithromax®)
- clarithromycin (Biaxin®)
- fidaxomicin (Dificid®)
most widely used
macrolides
Azithromycin and clarithromycin
- they have longer duration of action, which allows them to
be given less often. - They also produce fewer and milder GI tract side effects than erythromycin.
Fidaxomicin (Dificid)
- the newest macrolide antibiotic.
- It is indicated only for the treatment of diarrhea associated with Clostridium difficile.
Macrolides:
Mechanism of Action
Bacteriostatic
Prevent protein synthesis within bacterial cells
* Bacteria will eventually die
* In high enough concentrations, may also be
bactericidal
Macrolides: Indications
“Strep” infections
Mild to moderate resp infections
Haemophilus influenza;
Spirochetal infections- Syphilis and Lyme disease;
Gonorrhea; Chlamydia.
Fidaxomicin (Dificid) adverse effects
- The most common adverse effects are nausea, vomiting,
and GI bleed
Macrolides: Adverse Effects
- GI effects, primarily with erythromycin
- Nausea, vomiting, diarrhea, hepatotoxicity, flatulence,
anorexia, heartburn, abnormal taste. - Report immediately, chest pain, palpitations,
dizziness, jaundice or hearing loss
- Report immediately, chest pain, palpitations,
Tetracyclines examples
- doxycycline hyclate (Doxycin®, Vibramycin®, others)
- minocycline hydrochloride (Minocin®)
- tigecycline (Tygacil®)
tigecycline (Tygacil®)
- Tetracycline
- indicated for complicated infections, intra- abdominal
infections, and community acquired pneumonia; the drug should be used only when other treatments are not available.
Tetracyclines action
Bacteriostatic
inhibit bacterial growth
Inhibit protein synthesis; Bind (chelate) to Ca, Mg and Al ions to form insoluble complexes
Tetracyclines nursing considerations
Dairy products, antacids, and iron
salts reduce oral absorption of tetracycline; discolors of teeth
- Strong affinity for calcium precludes use in:
- Children younger than 8 years of age
- Results in discoloration/ mottling of permanent teeth
- Pregnant women and nursing mothers
- can be another route of exposure leading to tooth discoloration in
nursing children - May stunt fetal skeletal development if taken during
pregnancy
Tetracyclines Uses
wide spectrum Gram-negative and gram-positive organisms; acne in adults and adolescents; chlamydia, mycoplasma pneumonia; h.pylori; syphilis; resistant to gonorrhea.
Tetracyclines: Adverse Effects
- Alteration of the intestinal flora
- May also cause:
- Diarrhea
- Vaginal candidiasis
- Gastric upset
- Enterocolitis
- Maculopapular rash
- Other effects photosensitivity, coagulation irregularities and
hemolytic anemia
antibiotic Nursing Interventions
- obtain cultures from appropriate
sites before beginning antibiotic therapy ( including
bloodwork- blood cultures). - Instruct patients to take antibiotics exactly as
prescribed and for the length of time prescribed;
they should not stop taking the medication early
when they feel better. - Watch for for signs and symptoms of superinfection
or secondary infections: fever, perineal itching,
cough, lethargy, or any unusual discharge. - All oral antibiotics are absorbed better if taken with
at least 180 mL of water.
Avoid simultaneous use of antacids, antidiarrheal drugs, dairy products, calcium, iron preparations which may reduce the absorption of tetracycline. Consume drug 2 hour before or 3 hour after these.
Sulfonamides pt teaching
- Take with 2 000 to 3 000 mL of fluid per 24 hours.
- Take oral doses with food.
- Encourage patients to immediately report worsening
abdominal cramps, stomach pain, diarrhea, hematuria,
severe or worsening rash, shortness of breath, and fever. - Taking 2-3 L. in 24 hrs will prevent drug related crystalluria
B- Lactams - Penicillins pt teaching
- Take oral doses with water (not juices) because acidic fluids
may nullify the drug’s antibacterial action. - consumption of probiotics such as lactobacillus supplements or cultured dairy products like yogurt or buttermilk or kefir to prevent normal GI flora killed off causing c-diff
B-Lactams- Cephalosporins pt teaching
- give PO with food to decrease GI
upset even though this will delay absorption. - Some of these drugs may cause a disulfiram (acute alcohol
intolerance)
Signs and symptoms of disulfiram (acute alcohol intolerance)
stomach cramping, nausea,
vomiting, headache, diaphoresis, pruritus, hypotension
Macrolides drug-drug interaction
- will cause severe
interactions with other protein-bound drugs i.e.
carbamazepine, cyclosporine, theophyline, warfarin
sodium. - can reduce the efficacy of oral contraceptives.
Organisms that produce ESBL
are resistant to all B-lactam antibiotics and can be
treated only with carbapenems or sometimes quinolones
Aminoglycosides
gentamicin
streptomycin
tobramycin
amikacin
paromomycin
neomycin
Aminoglycoside action
- Very potent antibiotics with serious toxicities
- Bactericidal; prevent protein synthesis
- Kill mostly gram-negative some
gram-positive bacteria - Bactericidal
- Prevent protein synthesis; Often used in combination with other antibiotics for synergistic effects.
Aminoglycoside Uses
- Drug of choice for virulent infections
- Kill mostly gram-negative bacteria, some
gram-positive bacteria; Used for certain gram-positive infections that are resistant to other antibiotics such as Enterococcus spp., S. aureus. MRSA, ESBL
Aminoglycosides: Adverse
Effects
- drug monitoring required to prevent toxicities
- Nephrotoxicity; occurs in 5-25% patients and usually reversible.
- Ototoxicity affects hearing and balance functions (vestibular
impairment) in 3-14% of patients. Often not reversible such as hearing loss from damage to 8th cranial nerve.
Superinfection
Postantibiotic effect (PAE)
a period of continued bacterial growth suppression that occurs after short term antibiotic exposure, as in once- daily aminoglycoside dosing. The PAE is enhanced with higher peak drug concentrations and concurrent use of B-lactam antibiotics.
Aminoglycosides: Drug toxicity
increased when used with other drugs with nephrotoxic
properties such as vancomycin. And the concurrent use of loop diuretics
increases the risk for otoxicity. They reduce GI flora and thus reduce
vitamin K produces. Can potentiate warfarin.
Quinolones
(referred to as fluoroquinolones)
Action
- A potent bactericidal broad spectrum antibiotic
- Bactericidal
- Alter deoxyribonucleic acid (DNA) of bacteria, causing death
- do not affect human DNA
Quinolones Uses
- S. aureus
- Effective against gram-negative organisms and some gram-positive organisms;
- Potent and broad-spectrum for complicated urinary tract, respiratory, bone and joint, gastrointestinal, and skin infections.
- Serratia marcescens, and Mycobacterium fortuitum
Quinolones: Interactions
- Oral quinolones: antacids, calcium,
magnesium, iron, zinc preparations, or
sucralfate reduce absorption
-Patients need to take the interacting drugs at least 1 hour before or after - dairy
- En tube
- probenecid
- oral anticoagulants
- Nitrofurantoin
Quinolones: adverse effects
- CNS depression
- Nausea, vomiting, diarrhea, constipation,
- oral candidiasis,
- dysphagia,
- increased liver function
- Superinfection
- rash
- ruptured tendons
Clindamycin Action
Bactericidal or bacteriostatic depending on the concentration of the drug at the site of infection and on the infecting bacteria.
It inhibits protein synthesis in bacteria
Clindamycin uses
Chronic bone infections, genitourinary infections, intra-abdominal infections, other serious infections
Clindamycin adverse effects
GI including nausea, vomiting, abdominal pain, diarrhea, anorexia
Superinfection i.e.
C. difficile infection-
linezolid (Zyvoxam)
- bactericidal
- inhibits bacterial synthesis
- new class; used for VRE, MRSA and other Hospital Acquired Infections
linezolid contraindications
avoid tyramine containing foods; avoid concurrent use with SSRI due to Serotonin Syndrome
Metronidazole
- bactericidal
- interferes with microbial DNA synthesis; similar to quinolones
- given for C. difficile
- treatment of choice for protozoal infections such as amebiasis and trichomoniasis
- Metronidazole- do not chew extended release capsule; avoid alcohol 24hrs before treatment and 36 hrs after last dose
Nitrofurantioin action
Bactericidal
Interferes with the activity of enzymes that regulate bacterial carbohydrate metabolism and disrupting bacterial cell wall formation
Nitrofurantioin uses
UTIs
Nitrofurantioin Adverse effects/considerations
Watch kidney function; drug concentrates in the kidney
Superinfection
Give with fluids, food or milk to reduce GI upset; to prevent tooth staining do not crush tablets
Vancomycin
Bactericidal antibiotic that is structurally unrelated to any other
commercially available antibiotic
Antibiotic of choice for MRSA infection
Not active against gram-negative bacteria, fungi or yeast.
Must monitor blood levels to ensure therapeutic
levels and prevent toxicity
May cause ototoxicity and nephrotoxicity
Vancomycin action
Bactericidal
Only gram positive bacteria effective
Binds to bacterial wall, producing immediate inhibition of cell wall synthesis and death. This is different than B-lactam
Vancomycin uses
Antibiotic of choice for MRSA
Because it is poorly absorbed, the oral route is used for its local effects on the surface of the GI tract infection - Oral vancomycin is indicated for the treatment
of antibiotic-induced colitis (C. difficile) and for
the treatment of staphylococcal enterocolitis.
Vancomycin adverse effects
Red Man Syndrome- flushing, erythema or itching of the head, face, neck and upper trunk.
- Superinfection
vancomycin nursing considerations
Infuse IV slowly to reduce incidence of Red Man Syndrome.
Rapid infusion may also cause low B/P, pain in back and chest, dyspnea
Tough levels done
Red Man syndrome
flushing, erythema or itching of the head, face, neck and upper trunk area. It is most commonly seen when the drug is infused too rapidly. It can usually be alleviated by giving the infusion of the dose over at least one hour. It is bothersome side effect but not
harmful.
Colistimethate sodium (Coly-Mycin)
used to treat KPC as its often one of the only drugs available.
- Serious adverse effects includes kidney failure, neurotoxic effects such as, paresthesia, numbness, tinging, vertigo, dizziness and impaired
speech.
Aminoglycosides and Vancomycin may cause?
ototoxicity or nephrotoxicity
Linezolid considerations
Assess for concurrent use of SSRI because of drug induced
serotonin syndrome.
Assess for tyramine foods (wine, aged cheese, soy sauce,
smoked fish or meat) because of risk of hypertensive crisis.
signs and symptoms of
superinfection
fever, perineal itching,
cough, lethargy, or any unusual discharge
Fungal infections are also known as
mycoses
Fungi that cause integumentary infections are known as
dermatophytes
Dermatomycoses
Moulds
Multicellular
Characterized by long, branching filaments called hyphae
Yeasts
Single-cell fungi
Reproduce by budding
Candida albicans
May follow antibiotic therapy, antineoplastics,
or immunosuppressants (corticosteroids)
May result in overgrowth and systemic infections
Growth in the mouth is called thrush or oral
candidiasis.
Common in newborn infants and
immunocompromised patients
Vaginal candidiasis
Yeast infection
Pregnant women, women with diabetes, women
taking oral contraceptives
Polyenes
Amphotericin B (systemic)
Nystatin (topical)
(also available with metronidazole-topical or vaginal)
Polyenes action
Binds to sterols on cell membrane lining of fungi; causes fungal cell death
- Do not bind to human cell membranes or kill
human cells
Polyenes uses
Systemic and topical fungal infections
Nystatin- candidal infections
Amphotericin B is drug of choice for the treatment of many severe systemic fungal infections.
fluconazole
passes into the cerebrospinal
fluid and inhibits the growth of cryptococcal
fungi; effective in the treatment of
cryptococcal meningitis
Amphotericin B Adverse
Effects
IV infusion syndrome referred to ‘shake and bake’ syndrome including fever, chills, N&V> B/P, > hr, HA, malaise, muscle and joint pain, anorexia
- dyssrthymias
- nephrotoxicity
tinnitus; visual disturbances;
paresthesias; convulsions
Pulmonary infiltrates
Amphotericin B Adverse
Effects: Prevention
- Prescribers commonly order various premedications: antiemetics, antihistamines,
antipyretics, and corticosteroids - Prevent or minimize infusion-related reactions to
amphotericin B
fluconazole adverse effects
Nausea, vomiting, diarrhea, stomach pain,
Increased liver enzymes
Use with caution in patients with kidney or liver dysfunction
nystatin (topical) adverse effects
Nausea, vomiting, anorexia, diarrhea, rash,
urticaria
nursing considerations: Triazoles and Imidazoles
- Use with caution in patients with kidney or liver dysfunction
- For IV dose, if itching or a rash occurs, stop the infusion, take vital signs and report
Nystatin nursing considerations
dropped directly on the tongue using the calibrated dropper and held in the mouth for as long as possible swish & swallowed.
