Three days after undergoing coronary bypass surgery, a 67-year-old man becomes unresponsive and hypotensive. He is intubated, mechanically ventilated, and a central line is inserted. Vasopressin and noradrenaline infusions are begun. A Foley catheter is placed. Six days later, he has high unrelenting fevers. He is currently receiving noradrenaline via an infusion pump. His temperature is 39.6°C (102.3°F), pulse is 113/min, and blood pressure is 90/50 mm Hg. Examination shows a sternal wound with surrounding erythema; there is no discharge from the wound. Crackles are heard at both lung bases. Cardiac examination shows an S3 gallop. Abdominal examination shows no abnormalities. A Foley catheter is present. His hemoglobin concentration is 10.8 g/dL, leukocyte count is 21,700/mm3, and platelet count is 165,000/mm3. Samples for blood culture are drawn simultaneously from the central line and peripheral IV line. Blood cultures from the central line show coagulase-negative cocci in clusters on the 8th postoperative day, and those from the peripheral venous line show coagulase-negative cocci in clusters on the 10th postoperative day. Which of the following is the most likely diagnosis in this patient?

Central line-associated blood stream infection

Catheter-associated urinary tract infection

Ventilator-associated pneumonia

A 38-year-old female presents to the emergency room with fevers, fatigue, and anorexia for over a month. Past medical history includes mild mitral valve prolapse. She underwent an uncomplicated tooth extraction approximately 6 weeks ago. Her vital signs include a temperature of 100.8 F, pulse of 83, blood pressure of 110/77, and SpO2 of 97% on room air. On exam, you note a grade III/VI holosystolic murmur at the apex radiating to the axilla as well as several red, painful nodules on her fingers. Which of the following is the next best course of action?

Obtain blood cultures x3 sites over 1 hour and start empiric antibiotics

Blood cultures are not needed. Start empiric antibiotics

Start anticoagulation with heparin

Consult cardiothoracic surgery for mitral valve replacement

Obtain blood cultures x3 sites over 24 hours and start antibiotics after culture results are available

A 38-year-old previously healthy woman develops septic shock from necrotizing fasciitis of the lower extremity. Despite three debridements, broad-spectrum antibiotics (vancomycin, meropenem, clindamycin), IVIG, and aggressive critical care support, she develops refractory shock requiring norepinephrine 1.2 mcg/kg/min, vasopressin 0.04 units/min, and epinephrine 0.1 mcg/kg/min. Lactate is 15 mmol/L. Surgical team recommends hemipelvectomy as last option for source control. Family is devastated. ICU team notes SOFA score of 18. Synthesize an approach to management and decision-making.

Multidisciplinary meeting with surgery, ICU, palliative care, and family to discuss realistic outcomes, quality of life, and patient values before decision

Transfer to ECMO center for consideration of VA-ECMO as bridge to hemipelvectomy

Continue medical management for 24 hours and proceed with hemipelvectomy only if shock improves

Decline surgery based on futility given SOFA score >15 and initiate comfort care

Proceed with hemipelvectomy immediately as only chance for survival with informed consent from family

A 52-year-old woman with septic shock from intra-abdominal infection undergoes emergency exploratory laparotomy for perforated diverticulitis with fecal peritonitis. Surgery reveals extensive contamination requiring damage control approach. Postoperatively, she requires norepinephrine 0.8 mcg/kg/min plus vasopressin 0.04 units/min, has lactate of 8.5 mmol/L, temperature 35.2°C, INR 2.8, pH 7.18, and base deficit -12. Planned return to OR is in 48 hours. Evaluate the priority interventions to optimize outcome.

Aggressive rewarming, correction of coagulopathy, ongoing resuscitation, and source control at planned reoperation

Immediate return to OR for definitive repair and anastomosis

Start therapeutic hypothermia and delay reoperation until hemodynamically stable off vasopressors

Initiate high-dose vasopressors to maintain MAP >75 mmHg and early enteral nutrition

Administer massive transfusion protocol and emergency re-exploration within 6 hours

A 70-year-old man with recently diagnosed small cell lung cancer presents with septic shock from pneumonia. After initial resuscitation, he requires norepinephrine 0.6 mcg/kg/min and has a lactate of 7.8 mmol/L. His SOFA score is 14. The family requests 'everything be done,' but the patient had previously told his oncologist he would not want prolonged intensive care if his cancer prognosis was poor. Staging shows extensive-stage disease. The ICU team debates goals of care. What represents the most ethically appropriate approach to decision-making?

Arrange urgent palliative care consultation and family meeting to discuss patient's previously expressed wishes and realistic prognosis

Continue maximum therapy per family wishes as they are legal decision-makers

Obtain ethics consultation to overrule family wishes based on futility

Continue current therapy for 72 hours then reassess based on clinical trajectory

Transition to comfort care based on poor oncologic prognosis and high SOFA score

Blood culture technique and interpretation

Blood Culture Technique - The Perfect Pour

Aseptic Technique: Skin prep is crucial. Use 2% chlorhexidine; it's superior to povidone-iodine in reducing contamination.
Site & Number: Collect from ≥2 separate venipuncture sites to distinguish true bacteremia from contaminants. Avoid drawing from existing lines unless a catheter-related infection is suspected.
Volume & Timing: The volume of blood is the single most important factor for yield. Aim for 10-20 mL per set. Always draw cultures before administering antibiotics.

⭐ Collecting >3 sets of blood cultures provides minimal additional diagnostic yield (<5% increase) but increases the risk of false positives and unnecessary antibiotic use.

Result Interpretation - Signal vs. Noise

True Pathogen vs. Contaminant: Differentiating is key. Consider the following factors:
- Number of Positive Sets:
  - True infection: Growth in ≥2 separate culture sets.
  - Contamination: Usually growth in only 1 set.
- Identity of Microorganism:
  - Common Pathogens: S. aureus, E. coli, Klebsiella, S. pneumoniae, Pseudomonas.
  - Common Contaminants: Coagulase-negative staph (CoNS), Corynebacterium (diphtheroids), Cutibacterium acnes.
- Time to Positivity (TTP):
  - A TTP of <24 hours suggests a higher bacterial load and is more likely a true pathogen.
- Clinical Context:
  - Always correlate with the patient’s clinical status. A sick patient with a positive culture points to a true infection.

⭐ While Coagulase-Negative Staphylococci are the #1 contaminant, they are a common cause of true bacteremia in patients with prosthetic devices, central lines, or immunosuppression.

Common Organisms - The Usual Suspects

A key step in sepsis management is distinguishing true pathogens from contaminants, especially when interpreting blood cultures.

Common Contaminants	Common True Pathogens
* Coagulase-negative staphylococci (CoNS)	* Staphylococcus aureus
* Corynebacterium spp. (diphtheroids)	* Escherichia coli & other Enterobacteriaceae
* Bacillus spp. (not anthracis)	* Pseudomonas aeruginosa
* Cutibacterium (Propionibacterium) acnes	* Streptococcus pneumoniae & other Streptococci
	* Candida spp.

Always obtain blood cultures before starting antibiotics to maximize diagnostic yield.

Draw at least two sets from different venipuncture sites to distinguish true pathogens from contaminants.

Strict aseptic technique is critical to prevent contamination, most commonly with Staphylococcus epidermidis.

Inoculate 10-20 mL of blood per culture bottle for optimal sensitivity in adults.

A positive result allows for de-escalation to narrow-spectrum, targeted antibiotic therapy.