Infectious Diseases I

antibiotic therapy should be considered if there is strong

clinical suspicion for infection (Answer C is correct).

Waiting for final culture results before initiating antimi-

crobial therapy in patients thought to have a CAUTI may

delay appropriate treatment (Answer A is incorrect).

Although it is recommended to discontinue the urinary

catheter and replace as necessary, a confirmatory uri-

nalysis is not needed if the catheter has been indwelling

for less than 2 weeks (Answer D is incorrect).

Answer: B

The patient had an appropriate clinical response to ther-

apy in less than 72 hours and should be limited to 7 days

of effective therapy (Answer B is correct). Fourteen

days of therapy is appropriate if the patient shows clini-

cal signs and symptoms of infection after 72 hours of

effective therapy (Answer D is incorrect). There are

no recommendations for antibiotic courses of 5 or 10

days in the treatment of CAUTI (Answers A and C are

incorrect).

Answer: D

This patient has complicated intra-abdominal infection

from secondary peritonitis caused by colonic perfora-

tion. Although it is community acquired, the presence

of septic shock suggests severe classification increas-

ing the risk of gram-negative MDROs (Answer C is

incorrect). The involvement of the colon also obligates

antibiotic therapy active against anaerobes and entero-

cocci (Answer B is incorrect); MRSA is an unlikely

pathogen (Answer A is incorrect). According to this,

piperacillin/tazobactam is the most appropriate agent

listed (Answer D is correct).

The approach to managing a complicated intra-

abdominal infection includes timely source control

and initiation of empiric antimicrobial therapy active

against likely pathogens. This involves assessment of

the anatomic location of the source, risk factors for mul-

tidrug-resistant organisms (i.e., community- or health

care–associated disposition), and severity of illness. This

patient has community-acquired secondary peritonitis

from a distal small bowel perforation with concomi-

tant septic shock. Although his disease is community

acquired, the presence of septic shock suggests a severe

classification, increasing the risk of gram-negative mul-

tidrug-resistant organisms and involvement of the distal

small bowel obligates empiric coverage for anaerobic

pathogens and enterococci, for all of which meropenem

plus linezolid should provide appropriate empiric cover-

age (Answer A is correct). Ertapenem would likely have

adequate empiric coverage for enteric, gram-negative

pathogens, both aerobic and anaerobic; however, lack

or enterococcal coverage makes it less optimal (Answer

B is incorrect). Ciprofloxacin lacks sufficient activity

against enterococci or anaerobic pathogens, and MRSA

coverage with vancomycin is unnecessary (Answer C is

incorrect). Cefazolin is too narrow as empiric therapy

for a severe community-acquired complicated intra-

abdominal infection, and fluconazole should be reserved

for definitive therapy for fluconazole-susceptible yeast

identified on final culture (Answer D is incorrect).

Shorter durations of antimicrobials have shown out-

comes similar to longer durations (Answers C and D

are incorrect). Although 4 or 5 days of therapy has been

shown in the general population, data are limited in the

critically ill population (Answer A is incorrect). The SIS

recommends a limit of 8 days of antimicrobial therapy

after source control in critically ill patients (Answer B

is correct).

Acute necrotizing pancreatitis often presents with signs

and symptoms consistent with systemic inflammatory

response syndrome. However, most cases of severe

necrotizing pancreatitis are sterile and do not require

antibiotic therapy. The presence of a pancreatic pseu-

docyst or abscess increases the likelihood of infected

necrotizing pancreatitis, which thus warrants empiric

antimicrobial therapy. However, this patient has no

evidence of these on CT scan; thus, empiric antibiotic

therapy is not indicated (Answers A–C are incorrect).

Moreover, prophylactic antimicrobial therapy is not

recommended in the recent guidelines, despite the

presentation of systemic inflammation and pancreatic

necrosis (Answer D is correct). A prospective, random-

ized, noninferiority study most strongly supports these

recommendations.

This patient has acute, severe pancreatitis with CT evi-

dence of pancreatic abscess. Gram stain of fluid obtained

from CT-guided drainage suggests the presence of