NAPLEX- SSTI McGraw Hill

Vibramycin is available for administration in all of the following formulations? Select all that apply.

A

Parenteral

B

Suspension

C

Syrup

D

Patch

A, B, C

.Doxycycline is available in all of the listed formulations except patch. In addition, it is available in oral tablet and capsule.

OT is a 45-year-old man with diabetes who was diagnosed with a mild foot infection. Since he has a history of chronic renal insufficiency, the provider would like to use an antibiotic that does not have to be adjusted for renal dysfunction. To treat his diabetic foot infection, select the antibiotics that do not require adjustment for renal dysfunction. Select all that apply.

A

Cefazolin

B

Linezolid

C

Nafcillin

D

Vancomycin

B, C

.Linezolid is metabolized through oxidation and is mostly excreted through non-renal routes. It does not require adjustment for renal insufficiency.

Answer c is correct.Nafcillin undergoes hepatic metabolism and is primarily eliminated in the feces. Adjustment of dose or interval is only required in patients with both renal and hepatic insufficiency.

Answer a is incorrect. The major route of elimination for cefazolin is through the kidneys; therefore, cefazolin requires renal dose adjustment.

Answer d is incorrect. The major route of elimination of vancomycin is through the kidneys; therefore, vancomycin requires dose adjustment for renal dysfunction.

PT is a 58-year-old woman with diabetes who will be started on Zosyn and a methicillin-resistant Staphylococcus aureus (MRSA)-active antibiotic for her diabetic foot infection with osteomyelitis. The patient's other medications include simvastatin, metoprolol, fenofibrate, escitalopram, and metformin. The team is concerned with potential drug interactions and wants to avoid medications that interact with the patient's chronic medications. Which of the following medications is the most appropriate for MRSA coverage?

A

Daptomycin

B

Linezolid

C

Moxifloxacin

D

Vancomycin

D

.Daptomycin, when used concurrently with simvastatin and fenofibrate, may increase the risk of myopathy. If there are no other options, simvastatin and fenofibrate may be temporarily discontinued, during daptomycin therapy, if deemed safe for the patient.

Answer b is incorrect.Linezolid used in concurrently with a selective serotonin reuptake inhibitor (SSRI) may increase risk of serotonin syndrome. It is a relative contraindication and should be avoided unless there are no alternatives. Alternatively, SSRIs may be temporarily discontinued, during linezolid therapy, if deemed safe for the patient.

Answer c is incorrect. Fluoroquinolones, including moxifloxacin, are not active against MRSA.

Which of the following doses and formulations are correct for the empiric treatment of a moderate to severe, polymicrobial cellulitis?

A

Moxifloxacin 400 mg PO every day

B

Ertapenem 1 g IV daily

C

Unasyn 875 mg PO every 12 hours

D

Cefazolin 1 g IV every 8 h

B

.Ertapenem is a carbapenem that has broad spectrum of activity including S. aureus, streptococci, Gram-negatives, anaerobes. Ertapenem would not be an appropriate choice when there is concern for Pseudomonas.

Answer a is incorrect.Moxifloxacin dosing is correct; however, for moderate to severe infections, parenteral therapy is recommended.

Answer c is incorrect.Ampicillin/sulbactam does not come in oral formulation. Parenteral Ampicillin/sulbactam would be an appropriate choice for moderate to severe infections. If oral therapy was indicated, could consider using amoxicillin/clavulanate as they have similar spectrums of activity.

Answer d is incorrect.Cefazolin is narrow in spectrum of activity and does not cover gram-negative or anaerobic bacteria that are concerning in a polymicrobial infection.

RD is an 18 year-old woman who presents to a clinic with cellulitis. The local antibiogram reveals that less than 1% of S. aureus that were isolated last year were methicillin-resistant. The treating physician would like to prescribe an oral antibiotic regimen that covers both S. aureus and GAS. Which of the following regimens is the most appropriate for monotherapy?

A

Amoxicillin

B

Cephalexin

C

Ciprofloxacin

D

Trimethoprim-sulfamethoxazole

B

.Cephalexin is a first-line antibiotic regimen for cellulitis. It is active against both methicillin-sensitive S. aureus (MSSA) and group A streptococcus (GAS). As the local prevalence of methicillin-resistant S. aureus (MRSA) is low and the patient does not have specific history to suggest so, RD does not need an MRSA-active treatment.

Answer a is incorrect.Amoxicillin is active against GAS, but is inactivated by penicillinases that most S. aureus strains produce.

Answer c is incorrect.Ciprofloxacin has very unreliable activity against gram-positive organisms such as S. aureus and GAS.

Answer d is incorrect. While trimethoprim-sulfamethoxazole has excellent activity against S. aureus (including caMRSA, which is not needed for this patient), it lacks activity against GAS. Therefore, another agent would need to be added to adequately cover both S. aureus and GAS.

Which of the following medications are contraindicated in a patient with a documented anaphylaxis to penicillin? Select all that apply.

A

Augmentin

B

Avelox

C

Dycill

D

Cleocin

A, C

Augmentin is the brand name for amoxicillin/clavulanate, which is a penicillin. It is contraindicated to give Augmentin with a documented IgE allergy to penicillin.

Answer c is correct. Dycill is the brand name for dicloxacillin. This is a penicillinase-stable penicillin and is therefore contraindicated with penicillin-anaphylactic allergy.

Answer b is incorrect, Avelox is the brand name for moxifloxacin. This is a fluroquinolone which is structurally dissimilar to the penicillin class.

Answer d is incorrect. Cleocin is the brand name for clindamycin. Often, this is used as an alternative agent for patients with severe penicillin allergies.

AB, a 30-year-old man who does not have any significant previous medical history nor drug allergies, was admitted to the hospital with an abscess and associated cellulitis. After appropriate drainage of the abscess, AB was initiated on intravenous vancomycin therapy. The culture from the incision and drainage grew community-associated methicillin-resistant Staphylococcus aureus (caMRSA). AB's clinical status improved with 2 days of vancomycin therapy and thus will be discharged home with an oral antibiotic to finish his therapy. Which of the following antibiotic(s) is/are appropriate step-down options for AB? Select all that apply.

A

Cephalexin

B

Minocycline

C

Tigecycline

D

Trimethoprim-sulfamethoxazole

B, D

.Minocycline is an oral antibiotic active against caMRSA used for the treatment of skin and soft tissue infections (SSTIs).

.Tigecycline, while active against caMRSA, is only available as a parenteral formulation.

AB, a 30-year-old man who does not have any significant previous medical history nor drug allergies, was admitted to the hospital with an abscess and associated cellulitis. After appropriate drainage of the abscess, AB was initiated on intravenous vancomycin therapy. The culture from the incision and drainage grew community-associated methicillin-resistant Staphylococcus aureus (caMRSA). AB's clinical status improved with 2 days of vancomycin therapy and thus will be discharged home with an oral antibiotic to finish his therapy. The medical team chose to prescribe sulfamethoxazole-trimethoprim (SMZ/TMP) for AB's cellulitis. What is the appropriate dosing regimen? AB has normal renal function and all labs are within normal limits.

A

Two double strength (DS) tablets by mouth every 12 hours

B

One single strength (SS) tablet by mouth every 12 hours is not recommended for treatment of community-associated methicillin-resistant Staphylococcus aureus (caMRSA).

C

One DS tablet by mouth daily.

D

5 mg/kg (based of trimethoprim component) every 8 hours.

A

SMP/TMZ one or two DS tablets by mouth every 12 hours is the appropriate dosing regimen.

PT is a 58-year-old woman with diabetes who will be started on Zosyn and a methicillin-resistant Staphylococcus aureus (MRSA)-active antibiotic for her diabetic foot infection with osteomyelitis. The patient's other medications include simvastatin, metoprolol, fenofibrate, escitalopram, and metformin. The team is concerned with potential drug interactions and wants to avoid medications that interact with the patient's chronic medications. Which of the following is a reasonable duration of antimicrobial therapy for PT's infection?

A

1 week

B

2 weeks

C

3 weeks

D

6 weeks

D

The typical duration of therapy for osteomyelitis is 4 to 6 weeks.

BC is a 40-year-old woman, who has hypertension and drug allergies to penicillins (angioedema, hives) and sulfa drugs (rash), presents to urgent care with a dry and intensely red lesion about 5 cm by 5 cm in size, with well-demarcated and raised borders on her right lower extremity. She describes having pain and burning sensation. What is the most appropriate oral antibiotic for BC's erysipelas skin and soft tissue infection (SSTI)?

A

Amoxicillin

B

Cefuroxime

C

Clindamycin

D

Vancomycin

C

.Clindamycin, an antibiotic available in an oral formulation, is active against group A streptococcus (GAS), which is the most common cause of erysipelas. It is a rational alternative for treating erysipelas in patients who have serious penicillin allergies.

Answer a is incorrect. While amoxicillin is active against GAS, the most common cause of erysipelas, BC has a serious allergy to penicillins.

Answer b is incorrect. While cefuroxime is active against GAS, the most common cause of erysipelas, BC's serious allergy to penicillins limits the use of cephalosporins.

Answer d is incorrect. While vancomycin does come in oral form, the oral form is not systemically absorbed through the gastrointestinal tract and is limited to the treatment of Clostridium difficile infections.

GT is a 60-year-old man who was initiated on vancomycin and piperacillin-tazobactam for a rapidly progressing cellulitis in the emergency department. Upon arrival to the critical care unit, GT was determined to have necrotizing fasciitis (NF). What, if anything, should be adjusted to the patient's antibiotic regimen?

A

Add clindamycin.

B

Change piperacillin-tazobactam to cefepime.

C

Discontinue piperacillin-tazobactam.

D

The current regimen is optimal, with no changes necessary.

A

.Clindamycin should be added to halt toxin production (by inhibiting protein synthesis) to minimize further damage to the tissues. It also provides additional activity for infections with high bacterial inoculum such as NF.

Answer b is incorrect. By switching from piperacillin-tazobactam to cefepime, the regimen loses anaerobic coverage. Anaerobes are the predominant organisms that cause type I NF.

HW is a 7-year-old girl who was bitten on the forearm by a dog. While the wound was superficial, it now shows signs of infection. The wound was thoroughly irrigated and cleaned. The patient does not have any allergies. What are the most common organisms that may cause the infection? Select all that apply.

A

Pasteurella multocida

B

Escherichia coli

C

Eikenella corrodens

D

Streptococci

A, D

Bite infections are typically caused by organisms present in the biting animal's mouth and, to a lesser extent, the victim's skin. P. multocida is a normal flora in the mouths of dogs and cats that is implicated in bite infections.

Answer d is correct. Streptococci are present in both mouths of dogs and on the human skin.

Answer b is incorrect.E. coli is a gram-negative organism that is not typically present in dog mouths or the skin of healthy humans.

Answer c is incorrect.E. corrodens causes infections after human bites, but not dog bites.

Select the antibiotic that may cause an adverse reaction during or soon after infusion characterized by itching, warmth, flushing, and rash (among other symptoms), especially if infused at a rate faster than recommended.

A

Ampicillin

B

Cefazolin

C

Daptomycin

D

Vancomycin

D

Vancomycin, if infused too quickly may cause Red man syndrome. Red man syndrome is caused by a nonimmune release of histamine and is characterized by itching, warmth, flushing, and rash (typically on face and upper torso). In some cases, angioedema, tachycardia, and hypotension may also occur. It typically occurs during, or soon after administration of vancomycin and resolves within a few hours after the infusion. For most patients, extending the infusion of vancomycin and/or pretreating with an antihistamine resolves future episodes of Red man syndrome.

Select the antibiotics that may be used for skin and skin structure infections (eg, cellulitis) that are eliminated via renal excretion. Select all that apply.

A

Oxacillin

B

Nafcillin

C

Vancomycin (parenteral)

D

Daptomycin

A, C, D (disagree with A, checked lexi and rxprep)

.Nafcillin is the only penicillinase-stable penicillins that undergoes hepatic elimination. Nafcillin is an intravenous antibiotic that may be used to treat skin infections caused by methicillin-sensitive S. aureus (MSSA) and group A streptococcus (GAS).

Answers a is correct.Oxacillin primarily undergoes renal elimination and may be used in the treatment of skin infections. Oxacillin is a penicillinase-stable penicillin like nafcillin; however, oxacillin undergoes renal elimination. Oxacillin may be used for skin infections (eg, cellulitis, osteomyelitis) caused by MSSA and GAS.

Answer c is correct. Intravenous vancomycin undergoes renal elimination and may be utilized in the treatment of skin infections, especially skin infections that are caused my methicillin-resistant S. aureus (MRSA).

Answer d is correct.Daptomycin undergoes renal elimination and may be utilized in the treatment of skin infections, especially skin infections that are caused my MRSA.

Which organism(s) is(are) the most common cause of skin and soft tissue infections (SSTIs)? Select all that apply.

A

Streptococcus pyogenes

B

Staphylococcus aureus

C

Pasteurella multocida

D

Enterobacter cloacae

A, B

Acute bacterial SSTIs are predominantly caused by gram-positive organisms, particularly those that are present on skin. S. pyogenes, a gram-positive bacterium, is a normal human skin colonizing organism which in the right circumstances can cause infection.

Answer b is correct.S. aureus is another gram-positive bacteria that can colonize certain parts of the human body and is among the most implicated cause of SSTIs.

Answer c is incorrect.P. multocida is only a common cause of infections from dog and cat bites.

Answer d is incorrect.E. cloacae, a gram-negative bacterium, may cause SSTIs. However, it is not a common pathogen and usually implicated in patients with predisposing comorbidities (eg, diabetics) and those with already damaged tissue.

HW is a 7-year-old girl who was bitten on the forearm by a dog. While the wound was superficial, it now shows signs of infection. The wound was thoroughly irrigated and cleaned. The patient does not have any allergies. What is the most appropriate antibiotic monotherapy for HW's dog bite wound infection?

A

Augmentin

B

Avelox

C

Cleocin

D

Doxycycline

A

Augmentin (amoxicillin-clavulanic acid) is active against the organisms responsible for dog bite infections and is the drug of choice for those who do not have contraindications.

Answer b is incorrect. While Avelox (moxifloxacin) is active against the typical organisms responsible for dog bite infections, fluoroquinolones are generally not recommended in children due to increased risk of severe adverse effects.

Answer c is incorrect. Cleocin (clindamycin) is not active against Pasteurella, one of the major pathogens isolated from dog bite infections. If clindamycin is prescribed, it should be combined with another agent that is active against Pasteurella.

Answer d is incorrect. While doxycycline is an alternative for dog bite infections in penicillin-allergic patients, tetracyclines are not recommended for children 8 years and younger due to risk of permanent discoloration of teeth.

OT is a 45-year-old man with diabetes who was diagnosed with a mild foot infection. Since he has a history of chronic renal insufficiency, the provider would like to use an antibiotic that does not have to be adjusted for renal dysfunction. Linezolid is chosen to treat OT's diabetic foot infection since it comes in both a parenteral and oral formulation. What is the mechanism of action of Linezolid?

A

Inhibits DNA gyrase

B

Inhibits bacterial cell wall synthesis

C

Bind to PBP2a grants anti-MRSA activity

D

Inhibits bacterial protein synthesis

D

.Linezolid inhibits bacterial protein synthesis by binding to 23s ribosomal RNA of the 50s subunit.

Answer a is incorrect. The fluoroquinolones exhibit their antibiotic effect vis inhibition DNA gyrase.

Answer b is incorrect. The β-lactams and vancomycin work via inhibition of bacterial cell wall synthesis.

Answer c is incorrect. Ceftaroline exhibits an antibiotic effect through binding to PBP2a grants anti-MRSA activity.

DM is a 51-year-old man with uncontrolled diabetes, 20-year 1-pack-per-day smoking history who just finished treatment for his first episode of a mild diabetic foot infection (DFI). He is interested in learning preventive strategies to reduce his chances of another infection. Which counseling point is appropriate for DM? Select all that apply.

A

Obtain periodic foot examinations.

B

Work toward improving his control of diabetes.

C

Work toward smoking cessation.

D

Walk in open-toed shoes or barefoot as much as possible to keep feet dry.

A, B, C

It is important for diabetic patients to have periodic foot examinations to ensure that their feet are in good condition and to screen for potential problems (such as worsening neuropathy through the monofilament test).

Answer b is correct. Improving control of his diabetes will reduce the progression of neuropathy, vasculopathy, and other diabetic complications which contribute to risk of foot infections.

Answer c is correct. Smoking is an independent risk factor for peripheral vascular disease, which contributes to poor blood supply to extremities and poor wound healing, and thereby increases risk of DFIs.

Answer d is incorrect. Well-fitting, closed footwear are recommended for diabetic patients to protect the feet from accidental trauma.

TR is a 29-year-old pregnant patient with a diagnosis of cellulitis. TR has no drug allergies and is not on any other medications. Select the most appropriate antibiotic that may be used to treat TR's infection.

A

Cefazolin

B

Doxycycline

C

Imipenem-cilastatin

D

Levofloxacin

A

.Cefazolin is pregnancy category B and is generally considered safe for use during pregnancy. In addition, cefazolin is active against methicillin-sensitive Staphylococcus aureus (MSSA) and group A streptococcus (GAS), the two most common causes of cellulitis.

Answer b is incorrect. Doxycyline is classified as pregnancy category D due to harmful risks to the fetus. Doxycycline crosses the placenta to cause discoloration of teeth and may also deposit into long bone to inhibit growth. Other adverse effects have been described as well.

Answer c is incorrect. Imipenem-cilastatin belongs to pregnancy category C, denoting observations of adverse effects in animal studies.

Answer d is incorrect.Levofloxacin belongs to pregnancy category C, denoting observations of adverse effects in animal studies.

AB, a 30-year-old man who does not have any significant previous medical history nor drug allergies, was admitted to the hospital with an abscess and associated cellulitis. After appropriate drainage of the abscess, AB was initiated on intravenous vancomycin therapy. The culture from the incision and drainage grew community-associated methicillin-resistant Staphylococcus aureus (caMRSA). AB's clinical status improved with 2 days of vancomycin therapy and thus will be discharged home with an oral antibiotic to finish his therapy. The medical team chose to prescribe sulfamethoxazole-trimethoprim (SMZ/TMP) for AB's cellulitis. Which of the following organisms commonly encountered in cellulitis are covered/treated with SMZ/TMP (Septra)? Select all that apply.

A

Methicillin-sensitive S. aureus (MSSA)

B

Mycoplasma pneumoniae

C

Pneumocystis jiroveci

D

Methicillin-resistant S. aureus

A, D

TMP/SMZ does not have activity against atypical bacteria such as M. pneumoniae. Additionally, atypical bacteria (eg, M. pneumoniae) are not causative organisms of cellulitis.

Answers a and d are correct. TMP/SMZ DOES have activity against many gram-positive organisms including S. aureus (MSSA and community-associated methicillin-resistant Staphylococcus aureus [caMRSA]).

Answer c is incorrect. TMP/SMZ DOES have activity against P. jiroveci. Often times you will see TMP/SMZ used as prophylaxis in severely immunocompromised patients. However, P. jiroveci would not be a cause of this patient's skin and soft tissue infection.

Patient NL is a 52-year-old man getting discharged from the hospital with a prescription for doxycycline due to cellulitis. What pertinent counseling point(s) should be provided to NL regarding this medication? Select all that apply.

A

Doxycycline may cause your teeth to turn brown.

B

Avoid direct sunlight for prolonged periods and wear sunscreen.

C

Doxycycline may turn your urine and tears into an orange-red color.

D

Avoid taking this medication with antacids.

B, D

.Doxycycline, as with all tetracyclines, can cause photosensitivity.

Answer d is correct. Divalent and trivalent cations (eg, iron, calcium, and magnesium) bind to doxycycline and other tetracyclines, reducing the amount of antibiotic absorption. Patients should avoid taking these two medications concurrently.

Answer a is incorrect. Tetracyclines may cause irreversible brown staining of teeth in young children (therefore is contraindicated in children ≤8 except in exceptional cases). As NL is 52 years old, this is not pertinent to him.

Answer c is incorrect.Doxycycline does not cause color change in bodily fluids. Other antibiotics, such as metronidazole and rifampin, cause bodily fluids to turn orange.

BC is a 40-year-old woman, who has hypertension and drug allergies to penicillins (angioedema, hives) and sulfa drugs (rash), presents to urgent care with a dry and intensely red lesion about 5 cm by 5 cm in size, with well-demarcated and raised borders on her right lower extremity. She describes having pain and burning sensation. What is the most likely type of skin and soft tissue infection (SSTI) that BC is experiencing?

A

Cellulitis

B

Folliculitis

C

Impetigo

D

Erysipelas

D

The clinical presentation is most consistent with erysipelas, an SSTI that affects the epidermis and lymphatics.

Answer a is incorrect. Cellulitis typically presents with flat, diffuse borders.

Answer b is incorrect. Folliculitis is an SSTI that is associated with hair follicles and is much smaller in size than described.

Answer c is incorrect. Impetigo is characterized by multiple small lesions and often pruritic.

Which of the following medications have interactions with divalent/trivalent cations? Select all that apply.

A

Principen

B

Dynacin

C

Levaquin

D

Bactocill

B, C

Dynacin is the brand name for minocycline which is a tetracycline. Tetracyclines as a class interact with divalent/trivalent cations.

Answer c is correct. Levaquin in the brand name for levofloxacin which is a fluroquinolone. The class of fluroquinolones interact with divalent/trivalent cations.

Answer a is incorrect. Principen is the brand name for ampicillin which is a penicillin. The penicillin class of antibiotics do not interact with divalent/trivalent cations.

Answer d is incorrect. Bactocill is the brand name for oxacillin. The penicillin class of antibiotics do not interact with divalent/trivalent cations.

ZD is a 50-year-old man (83.3 kg) who was admitted into the hospital for cellulitis and was empirically initiated on vancomycin 15 mg/kg every 12 hours. Because of an adverse reaction he suffered when he previously received vancomycin, the medical team would like to infuse vancomycin at a rate of 500 mg/h. The pharmacy policy for final concentration of reconstituted vancomycin is at 5 mg/mL. What is the correct rate of infusion (mL/h) for his vancomycin and how long will it take to infuse each dose?

A

50 mL/h for 5 hours

B

100 mL/h for 2.5 hours

C

125 mL/h for 2 hours

D

200 mL/h for 2.5 hours

B

ABW

TY is a 29-year-old woman with a mild penicillin allergy who is being treated with an intravenous antibiotic in the hospital for a severe lymphangitis. The patient is not receiving any other medications. One week into therapy, TY's creatine phosphokinase (CPK) elevated to 6 times above the normal level and she complains of muscle aches. Which antimicrobial agent is TY most likely receiving and contributing to this lab abnormality and symptom?

A

Cefuroxime

B

Daptomycin

C

Linezolid

D

Vancomycin

B

Patient NL is a 52-year-old man getting discharge from the hospital with a prescription for Doxycycline due to cellulitis. During discharge counseling, NL expresses concern that he may spread his infection to others. What are some measures he can take to minimize this risk? Select all that apply.

A

Wash linens with cold water.

B

Keep wound covered with a clean and dry dressing until it has healed.

C

Avoid sharing personal hygiene products with others.

D

As the infection is being treated with antibiotics, there are no precautions needed.

B, C

In order to prevent spread of infection, the wound should be covered until healed.

Answer c is correct. Sharing personal hygiene products such as razors may spread infection to others.

Answer a is incorrect. Linens should be washed using hot (not cold) water.

Answer d is incorrect. Even during treatment with effective antibiotics, it is possible to spread it to others.

Among the following, select the β-lactam(s) that have activity against penicillinase-producing S. aureus. Select all that apply.

A

Ampicillin

B

Cefazolin

C

Dicloxacillin

D

Doxycycline

B, C

What is the generic name of Omnicef?

A

Cefdinir

B

Cefpodoxime

C

Cefuroxime

D

Cephalexin

A

.Cefdinir is the generic name of Omnicef.

Answer b is incorrect.Cefpodoxime is the generic name of Vantin.

Answer c is incorrect.Cefuroxime is the generic name of Ceftin and Zinacef.

Answer d is incorrect.Cephalexin is the generic name of Keflex.