A 35-year-old man with a history of splenectomy following a car

accident, is hospitalized for pneumonia. A chest X-ray reveals a right lower

lobe lung consolidation. Sputum gram stain is positive for neutrophils and

gram-positive diplococci, which on culture are optochin sensitive.

Which microorganism is most likely implicated in this infection?

A 36-year-old man is on the 5^th

day of hospitalization after

abdominal surgery for Crohn’s disease. The patient has a right femoral central

venous catheter for parenteral nutrition which was placed right before surgery.

The patient develops high fever with chills and rigors. Blood cultures taken

both through the central venous catheter and a peripheral vein reveal Gram-positive

cocci that are coagulase-positive and catalase-positive.

Which is the causative infectious agent and resistance phenotype of most

importance in this case?

A 75-year-old man with neurogenic bladder has an indwelling long-term

urinary catheter. Due to ongoing health problems the patient is frequently

hospitalized. For the last two days, he has had fever and rigors, and blockage

of the catheter. Blood culture reveals the presence of Gram-negative bacilli

which are oxidase-positive and non-glucose fermenters on MacConkey agar.

Which bacterium is the most likely cause of the catheter–related

infection?

A 28-year-old man presents to A&E with high fever (40°C), productive

purulent cough and low blood pressure. His mother reports a laboratory

confirmed influenza infection two weeks ago, and that he was rather well until

earlier this morning when he suddenly developed high fever. A chest CT scan

reveals lung abscesses with cavity formation. Sputum Gram stain reveals

abundant neutrophils along with Gram-positive cocci arranged in clusters, which

on culture isolates were coagulase and catalase-positive.

Which infectious agent and associated factor are most likely responsible

for this patient’s symptoms?

A 20-year-old female student living on campus, suddenly develops extreme

headache, high-fever, vomiting and gradually becomes lethargic. The on-call

doctor at her local hospital notices a haemorrhagic maculopapular rash on both

her lower extremities. A lumbar puncture revealed the presence of 8000 white

cells/mm

Which infectious agent is the cause of this patient’s symptoms?

A 5-year-old fully immunized girl developed fever and sore throat, and

on examination the doctor observed white exudates on both tonsils. As a result,

he made a tentative diagnosis of pharyngotonsillitis. He swabbed the tonsillar

exudates and 24 hours later, cultures grew Gram-positive cocci in long chains. The

bacterium was beta-haemolytic on blood agar.

Which is the most likely pathogen which caused the disease?

Penicillins are an important class of antimicrobial agents, commonly used for community-acquired infections like urinary tract infections or bacterial skin and soft tissue infections.

Which of the following best describes the mechanism of action of penicillins?

A 30-year-old, sexually active woman, presents to the outpatient

department with symptoms of urinary urgency, dysuria, and low abdominal pain.  Culture of a midstream urine sample reveals the

presence of

What characteristic property is of importance to uropathogenic

Escherichia

coli