Infection, Pharmacology & VTE MCQs

A 45-year-old farmer sustains a severe open tibia fracture after being kicked by a horse inside a dirty barn. According to standard orthopedic guidelines for open fractures with heavy soil or agricultural contamination, what is the most appropriate initial prophylactic antibiotic regimen?

A patient develops a periprosthetic joint infection characterized by bacterial entry into a sessile state and biofilm formation. Which communication mechanism is essential for coordinating this transition based on bacterial population density?

A patient develops a chronic periprosthetic joint infection due to Staphylococcus epidermidis. Which of the following components of the bacterial biofilm is primarily responsible for conferring resistance to both host immune cells and systemic antibiotics?

A 65-year-old undergoes a total knee arthroplasty and later develops a chronic periprosthetic joint infection due to Staphylococcus epidermidis. Which phase of biofilm formation is characterized by the production of a polysaccharide intercellular adhesin (PIA) matrix?

Which of the following prophylactic systemic antibiotics exerts its bactericidal effect by binding directly to the D-alanyl-D-alanine terminus of cell wall precursor units?

A 4-year-old child presents with a limp, fever, and refusal to bear weight on the right leg. According to the Kocher criteria, which of the following is NOT one of the four primary predictors for differentiating septic arthritis from transient synovitis?

During the pathogenesis of periprosthetic joint infection, bacteria form a biofilm. Which phase of biofilm formation is characterized by the irreversible attachment of bacteria to the implant surface and production of an extracellular polymeric substance (EPS) matrix?

Staphylococcus epidermidis is a leading cause of prosthetic joint infections due to its ability to form a robust biofilm. Which of the following components is primarily responsible for facilitating intercellular adhesion within this biofilm?

A 60-year-old diabetic male presents with rapidly spreading erythema, severe pain out of proportion to exam, and crepitus in his lower leg. Surgical exploration reveals dishwater-like fluid. Type I necrotizing fasciitis, the most common variant, is typically caused by:

During the administration of a regional nerve block, a patient inadvertently receives an intravascular injection of bupivacaine and subsequently goes into cardiac arrest. Alongside standard ACLS protocols, what is the most appropriate specific antidote for this local anesthetic systemic toxicity (LAST)?

A 2-year-old child presents with a limp, low-grade fever, and refusal to bear weight. Laboratory studies show mild elevation of ESR and CRP. Blood cultures are negative at 48 hours. Joint aspiration yields synovial fluid with 45,000 WBCs/mm3. If special culture techniques or PCR were utilized, what is the most likely pathogen to be identified?

Prosthetic joint infections are characterized by bacterial formation of a protective biofilm. The extracellular polymeric substance (EPS) that comprises the bulk of this biofilm and shields bacteria from both the host immune system and antimicrobial agents is primarily composed of:

A 4-year-old child is brought to the ED refusing to walk on her right leg. She has a temperature of 38.8°C (101.8°F). Laboratory tests show an ESR of 45 mm/h, a WBC count of 13,000/mm^3, and a CRP of 3.5 mg/dL. According to the classic Kocher criteria and subsequent validated models (e.g., Caird), what is the approximate probability that this child has septic arthritis of the hip rather than transient synovitis?

A 60-year-old man with poorly controlled diabetes presents with a rapidly spreading erythematous, exquisitely tender swelling of his right leg. Crepitus is palpated. Gram stain of fluid from a blister reveals a polymicrobial infection including Gram-positive cocci and Gram-negative rods. What is the most appropriate initial management?