Empiric vancomycin and cefepime narrow to ceftriaxone after a negative MRSA nasal PCR and a susceptible Klebsiella culture in this composite MN650 Unit 6 analysis. Searches like "mn 650 unit 6 assignment example", "mn650 unit 6 sample" and "mn650 unit 6 example" land here.
Seventy-Two Hours of De-Escalation: From Vancomycin and Cefepime to Ceftriaxone in Hospital-Acquired Pneumonia
[Student Name]
Purdue University Global
MN650: Specialized Pharmacology for the AGACNP Acute Care NP
Unit 6 Assignment
[Instructor Name]
[Date]
Composite patient written as a model document. Doses and times are bracketed placeholders; nothing here is a prescribing instruction.
The Empiric Start, Briefly
A composite 70-year-old retired pharmacist, five days after a colectomy, develops fever of 38.7 °C, a new right lower lobe infiltrate and an oxygen requirement rising from 2 to 5 liters. He received [intravenous cefazolin and metronidazole] for surgical prophylaxis and a [three]-day course of [piperacillin-tazobactam] for a suspected wound infection within the past 90 days.
The IDSA and ATS guideline for hospital-acquired pneumonia supports empiric coverage for MRSA and for Pseudomonas when a patient has received intravenous antibiotics within the prior 90 days (Kalil et al., 2016). Breadth was correct on day one. Empiric regimen: [vancomycin, loading dose then maintenance dosed to an AUC target] and [cefepime at a composite dose]. Vancomycin is dosed to an area-under-the-curve target rather than to trough levels, as the revised consensus guideline recommends (Rybak et al., 2020).
Pending Results and the Decisions They Control
MRSA nasal PCR: controls whether vancomycin continues.
Sputum culture and susceptibilities: control whether cefepime continues or narrows.
Blood cultures: control duration and whether a bloodstream source needs its own plan.
Procalcitonin, trended: supports, but does not by itself decide, stopping or shortening.
Timeline
Hour 0. Cultures drawn; vancomycin and cefepime started within the first hour.
Hour 20. MRSA nasal PCR negative. Action: stop vancomycin. Evidence: in a meta-analysis, a negative MRSA nasal screen had a negative predictive value of about 96 percent for MRSA pneumonia (Parente et al., 2018). A negative swab is strong evidence against MRSA pneumonia in a setting with ordinary MRSA prevalence, and continuing vancomycin would add kidney risk without likely benefit. Caveat: in units where MRSA is very common, or when the patient's own history includes MRSA, the negative predictive value is lower and the decision would be revisited.
Hour 48. Blood cultures negative so far. Fever down to 37.9 °C; oxygen needs falling to 3 liters.
Hour 60. Sputum culture grows Klebsiella pneumoniae, susceptible to ceftriaxone, cefepime and ciprofloxacin, resistant to ampicillin. Action: change cefepime to [ceftriaxone at a composite dose]. Evidence: the organism is susceptible, and ceftriaxone is narrower, avoiding unnecessary antipseudomonal pressure.
Day 3. On ceftriaxone alone. Afebrile. Oxygen at 2 liters.
Day 7. Course complete if he remains stable.
The Two Decisions in Detail
Stopping vancomycin. The predictive-value data support stopping on a negative nasal PCR when MRSA is not otherwise likely. The case has no prior MRSA, no MRSA in his wound culture and no necrotizing features on imaging. The decision is recorded with the swab result and the time.
Switching to ceftriaxone. The organism's susceptibility profile shows no resistance to third-generation cephalosporins. Had the Klebsiella been resistant to ceftriaxone, suggesting an extended-spectrum beta-lactamase producer, a carbapenem would have been needed instead. In the MERINO trial of bloodstream infections with ceftriaxone-resistant E. coli or Klebsiella, piperacillin-tazobactam led to higher 30-day mortality than meropenem (Harris et al., 2018), so a carbapenem would have been chosen rather than simply continuing cefepime or switching to piperacillin-tazobactam.
Why Not Stop at the First Good News
By hour 48 he was improving, and it would have been tempting to narrow both drugs at once on clinical grounds alone. The analysis waits for the culture at hour 60 because narrowing before the organism is known risks leaving a resistant gram-negative organism untreated in a patient who is only beginning to recover. Vancomycin could be stopped earlier because the nasal PCR answered the MRSA question directly. The two decisions were made on different evidence and therefore at different times.
Oral Step-Down
By day four he was eating and absorbing, afebrile for 48 hours, with stable oxygen needs. An oral agent to which the Klebsiella is susceptible, such as [a composite oral agent], could complete the course at home or on the ward. The plan considers the switch at day four and makes it if his bowel function after surgery is reliable, since poor absorption would undo the benefit.
Stewardship Accounting
Compared with continuing the empiric pair for seven days, de-escalation removed about six days of vancomycin, with its kidney monitoring and level draws, and about five days of cefepime, a broad antipseudomonal agent whose overuse drives resistance on the unit. Those savings are recorded in the stewardship log, not as a cost figure but as days of therapy avoided.
Duration and What Would Reopen It
The 2016 guideline suggests a seven-day course for hospital-acquired pneumonia (Kalil et al., 2016). The plan sets seven days, ending on [date]. Reasons that would extend or reopen the decision, named in advance: a new fever or rising oxygen need after day three; a positive blood culture; an empyema or lung abscess on imaging; or a new organism in a repeat culture. If none occurs, ceftriaxone stops on day seven without a new order being needed.
References
Harris, P. N. A., Tambyah, P. A., Lye, D. C., Mo, Y., Lee, T. H., Yilmaz, M., Alenazi, T. H., Arabi, Y., Falcone, M., Bassetti, M., Righi, E., Rogers, B. A., Kanj, S., Bhally, H., Iredell, J., Mendelson, M., Boyles, T. H., Looke, D., Miyakis, S., ... Paterson, D. L. (2018). Effect of piperacillin-tazobactam vs meropenem on 30-day mortality for patients with E coli or Klebsiella pneumoniae bloodstream infection and ceftriaxone resistance: A randomized clinical trial. JAMA, 320(10), 984-994. https://doi.org/10.1001/jama.2018.12163
Kalil, A. C., Metersky, M. L., Klompas, M., Muscedere, J., Sweeney, D. A., Palmer, L. B., Napolitano, L. M., O'Grady, N. P., Bartlett, J. G., Carratalà, J., El Solh, A. A., Ewig, S., Fey, P. D., File, T. M., Restrepo, M. I., Roberts, J. A., Waterer, G. W., Cruse, P., Knight, S. L., & Brozek, J. L. (2016). Management of adults with hospital-acquired and ventilator-associated pneumonia: 2016 clinical practice guidelines by the Infectious Diseases Society of America and the American Thoracic Society. Clinical Infectious Diseases, 63(5), e61-e111. https://doi.org/10.1093/cid/ciw353
Parente, D. M., Cunha, C. B., Mylonakis, E., & Timbrook, T. T. (2018). The clinical utility of methicillin-resistant Staphylococcus aureus (MRSA) nasal screening to rule out MRSA pneumonia: A diagnostic meta-analysis with antimicrobial stewardship implications. Clinical Infectious Diseases, 67(1), 1-7. https://doi.org/10.1093/cid/ciy024
Rybak, M. J., Le, J., Lodise, T. P., Levine, D. P., Bradley, J. S., Liu, C., Mueller, B. A., Pai, M. P., Wong-Beringer, A., Rotschafer, J. C., Rodvold, K. A., Maples, H. D., & Lomaestro, B. M. (2020). Therapeutic monitoring of vancomycin for serious methicillin-resistant Staphylococcus aureus infections: A revised consensus guideline and review by the American Society of Health-System Pharmacists, the Infectious Diseases Society of America, the Pediatric Infectious Diseases Society, and the Society of Infectious Diseases Pharmacists. American Journal of Health-System Pharmacy, 77(11), 835-864. https://doi.org/10.1093/ajhp/zxaa036
How this MN650 Unit 6 example is structured
Time structures the analysis, because de-escalation is a sequence of decisions made as information arrives. Each entry on the timeline pairs a result with an action and the evidence for that action, so the paper reads as a chain, not a recap of the final regimen. The empiric section is deliberately brief: breadth was correct on day one, and the words go to narrowing, which is where the unit places its weight. Two decisions receive fuller treatment. Stopping vancomycin on a negative nasal swab is defended with the predictive-value data and a caveat about settings where MRSA is common. The switch to ceftriaxone is checked against the organism's resistance profile, and a sentence explains why an extended-spectrum beta-lactamase producer would have required a carbapenem instead. Duration follows the 2016 guideline's seven-day suggestion, and the reasons that might extend it are named in advance.
Get an MN650 Unit 6 example written to your instructions
Culture results, the antibiogram if the case includes one, and the rubric for your MN650 Unit 6 analysis are what the sample needs. It comes back free on a first request, usually within 24-48h, with each narrowing step tied to the result that justified it and whatever would reopen the decision listed beforehand. The paper above is an original model document written by our desk, not a submitted student paper and not an official Purdue University Global document.
MN650 Unit 6 questions, answered
What if the culture grows nothing?
Culture-negative pneumonia still allows de-escalation. The sample would narrow on a negative MRSA swab, clinical improvement and the most likely organisms for the setting, citing the guideline's approach. It would also say what the absence of growth can and cannot rule out, especially when antibiotics started before the specimen was collected.
Should procalcitonin drive the decision?
The 2016 guideline suggests using it together with clinical criteria to support stopping antibiotics, not by itself to decide whether to start. The sample uses a procalcitonin trend as supporting evidence for the duration decision and explains that limit, a sturdier position than treating a single value as a switch.
Can the sample use a different empiric regimen?
Yes. The regimen follows the case, the local antibiogram if one is provided and the risk factors the prompt describes. Piperacillin-tazobactam, meropenem or another antipseudomonal agent may be the right empiric choice elsewhere; the analysis structure, results paired with decisions, stays the same whichever drugs fill it.