T2Bacteria® Negative De-escalation

67-year-old female admitted for reduced intensity conditioning followed by Stem Cell transplant for acute myelogenous leukemia.

Discussion

Patients undergoing cytotoxic chemotherapy and hematopoietic stem-cell transplantation (HSCT) are at high risk for infection, particularly during the period of neutropenia and are often prescribed antibiotic prophylaxis with fluroquinolones. The majority of patients who develop fever during neutropenia have no identifiable site of infection and no positive culture results. IDSA guidelines recommend that every patient with fever and neutropenia receive empiric antibiotic therapy with an antipseudomonal beta lactam urgently after presentation, because infection may progress rapidly.1

De-escalation of antimicrobials is challenging in these scenarios, where cultures remain negative, and patients are often exposed to extended durations of broad-spectrum antimicrobials as information is not available to target therapy. This puts the patient at risk for collateral damage associated with antimicrobial therapy such as antimicrobial resistance and toxicity. T2Bacteria negative results in 3-5 hours can help clinicians to improve their empiric therapy for bloodstream infections by providing key information to help narrow a patient’s empiric therapy.

At the time of febrile episode in this case, the patient was on levofloxacin 500 mg daily for bacterial prophylaxis. She had blood cultures obtained and T2Bacteria ordered and was then initiated on broad spectrumtherapy with cefepime 2g IV q8h. Due to the patient’s history of recent HSCT, profound immunosuppression and neutropenia, she was at risk for organisms such as P. aeruginosa in addition to other common causes of febrile neutropenia such as Enterobacteriaceae and Gram-positive commensal bacteria.

The patient received 3 doses of cefepime (~24 hours of therapy) then therapy was de-escalated to ceftriaxone based on negative T2Bacteria Panel results to avoid unnecessary continuation of the broad spectrum, antipseudomonal beta-lactam. Ceftriaxone was continued for 4 more days until the patient defervesced, was hemodynamically stable, afebrile and displayed no other sign or symptom of infection. Once treatment of the febrile neutropenic episode was complete, the levofloxacin prophylaxis was reinitiated.

Presentation

67-year-old female admitted for reduced intensity conditioning followed by Stem Cell transplant for acute myelogenous leukemia. She also received methotrexate and tacrolimus for graft-versus-host disease prophylaxis. Patient's clinical course was complicated by grade 3 nausea, vomiting and mucositis, hyperglycemia and new onset left bundle branch block. Six days after transplant the patient developed febrile neutropenia with profound neutropenia, in which stat blood cultures (x2), T2Bacteria, procalcitonin and lactic acid were drawn, a chest X-ray was taken and cefepime was immediately initiated.

Patient Selection Criteria

Febrile neutropenia in patient with recent HSCT and profound neutropenia.

Evaluation and Treatment Decision

Diagnosis: Neutropenic fever.

Empiric Therapy: The patient was on levofloxacin 500 mg daily for bacterial prophylaxis at time of febrile episode. The patient was initiated on cefepime 2g IV q8h at time of fever spike.

Cefepime was chosen for coverage of common causative pathogens identified in febrile neutropenia.

Procalcitonin, lactic acid, and chest X-ray were benign with no positive findings.

T2Bacteria Panel Result: Negative for all panel pathogens (P. aeruginosa, E. faecium, S. aureus, E. coli and K. pneumoniae.)  

Blood Culture Result: no growth

Decision making based on T2Bacteria Result

A rapid T2Bacteria negative result allowed for ruling out of the most common ESKAPE pathogens. The high negative predictive value (99.7%) of the T2Bacteria Panel provided important diagnostic information that allowed for more informed treatment decisions, including early de-escalation of empiric antibiotic regimen, sparing the patient from unnecessary broad spectrum antibiotics and the potential risks associated with their prolonged therapy.

1. Freifeld AG, et al.  Clinical practice guideline for the use of antimicrobial agents in neutropenic patients with cancer: 2010 Update by the Infectious Diseases Society of America. Clin Infect Dis 2011; 52:427-31.

Thrombus in Left Popliteal Artery

Patient presented with acute onset of pain in his left lower extremity

Discussion

Rapid molecular diagnostics such as T2MR technology may help with prognosis of invasive candidiasis. The T2Candida Panel was utilized upon follow up to assess the clearance of candidemia along with clinical symptoms.

Presentation

A 45-year-old man with an extensive history of bicuspid aortic valve disease, aortic valve replacement and multiple cases of bacterial endocarditis was treated with prolonged courses of antibiotics and was placed on chronic suppression with amoxicillin 500 mg orally three times per day. He presented with acute onset of pain in his left lower extremity and was diagnosed with a thrombus in his left popliteal artery.  

Evaluation and Treatment Decision

Surgical Interventions: Left embolectomy with pathology revealing a thrombus with calcification and multiple fungal forms with pseudohyphae, which grew Candida parapsilosis, along with blood cultures and T2Candida Panel positive for Candida parapsilosis. Transesophageal echocardiogram (TEE) revealed trace aortic regurgitation and mild mitral regurgitation.

Initial Antifungal Regimen: Micafungin 150 mg IV daily PLUS fluconazole 600 mg (6 mg/kg) IV daily was started for suspected prosthetic valve endocarditis.

Additional Culture Data and Modified Antifungal Regimen: Blood cultures remained positive for C. parapsilosis after 14 days of antifungal treatment. Treatment was changed to liposomal amphotericin B 5 mg/kg IV daily, flucytosine 2500 mg orally every six hours and fluconazole 400 mg orally daily. All subsequent blood cultures were negative. Due to an episode of acute renal failure, his regimen was finally changed to micafungin 150 mg IV daily and flucytosine 2500 mg PO every 8 hours.

Follow-up Tomography/Angiography: Scan revealed activity on the aortic leaflets and right lateral wall of the ascending aorta three weeks after starting antifungal treatment.

Second T2Candida Panel Result and Modified Antifungal Regimen: T2Candida Panel completed two months after starting antifungal treatment remained positive for C. parapsilosis while blood cultures remained negative. The regimen was narrowed down to flucytosine 2500 mg orally every eight hours and fluconazole 400 mg orally daily. Repeat T2Candida Panel became negative five months after starting antifungal treatment.

Discharge and Follow-Up Plan: The patient was stable for one year but decided to discontinue his flucytosine, fluconazole, and amoxicillin. He developed low-grade fevers and repeat blood cultures were negative for bacteria but grew C. parapsilosisas did a follow-up T2Candida Panel. The patient was restarted on liposomal amphotericin B, flucytosine, and fluconazole. Blood cultures became negative, and the T2Candida Panel was negative after two weeks of antifungal treatment. TEE was unchanged and did not reveal any vegetations. Liposomal amphotericin B was discontinued after six weeks, and the patient remains stable on flucytosine and fluconazole.

Decision making based on T2Candida Result

The T2Candida Panel was used to assess for the presence of disease and the continuation of antifungal therapy, despite negative blood cultures.

 

Citation: Ahuja T, Fong K, Louie E. Combination antifungal therapy for treatment of Candida parapsilosis prosthetic valve endocarditis and utility of T2Candida Panel®: A case series. IDCases. 2019;15:e00525.  

Neutropenic Fever & P. aeruginosa Bloodstream Infection

A 23-year-old female with a history of acute myeloid leukemia and recent haploidentical stem cell transplant, cytokine release syndrome and severe mucositis following receipt of post-transplant cyclophosphamide therapy.

Discussion:

Upon admission, the patient was initially given cefepime for the treatment of febrile neutropenia. Due to the patient’s history of AML and neutropenia, she was at risk for organisms such as P. aeruginosa in addition to other common causes of febrile neutropenia such as Enterobacteriaceae.

At the time of admission, she had blood cultures obtained and T2Bacteria ordered. At this hospital, patient selection for T2Bacteria testing included onco-hematologic and HSCT patients with suspected bloodstream infections.

Bloodstream infections are a major cause of life-threatening complications in patients with cancer, due to the potential delays in chemotherapy, longer hospital stay, suboptimal treatment, higher mortality rate, and increased healthcare costs. The poor performance of blood cultures has a major impact on clinical management of febrile neutropenic patients, especially in cases of unexplained persistent fever. T2Bacteria direct from blood diagnostic technology provided clinically relevant information for the diagnosis of infection in this case of blood culture-negative febrile neutropenia. Cefepime was continued for a total of 7 days, which was 2 days longer than would have been prescribed based on the negative blood cultures after the patient defervesced and ANC increased to >500.

Presentation 

A 23-year-old female with a history of acute myeloid leukemia and recent haploidentical stem cell transplant, cytokine release syndrome and severe mucositis following receipt of post-transplant cyclophosphamide therapy. The patient developed fever and blood cultures, T2Bacteria and empiric antibiotics were ordered.

Patient Selection Criteria

Febrile neutropenia in a patient with AML

Evaluation and Treatment Decision

Diagnosis: Neutropenic fever

Empiric Therapy: Cefepime

Cefepime was chosen for coverage of common causative pathogens identified in febrile neutropenia.

T2Bacteria Result: Positive for P. aeruginosa and negative E. faecium, S. aureus, E. coli and K. pneumoniae.  

Blood Culture Result: No growth

Decision making based on T2Bacteria Result

A rapid T2Bacteria result allowed for early diagnosis of P. aeruginosa bacteremia and confirmation of effective empiric antibiotic therapy. Identification of P. aeruginosa by T2 also provided important diagnostic information that allowed for more informed treatment decisions, including the continuation of IV antibiotics for longer treatment duration.

 

Pulmonary Edema and Suspected Pneumonia

Patient had a history of multiple myeloma, prostate cancer and CHF.

Discussion

This case highlights not only T2Bacteria’s benefit of rapid identification but also the ability to detect the causative organism in the presence of antibiotics as this patient had received the dose of vancomycin before the T2Bacteria was drawn.

Utilization of the T2Bacteria test allows for directed therapy on the same day as the identification of suspected infection. In this case, it took almost 48 hours from admission to identify S. aureus in the blood (Day 3 of admission). Ordering T2Bacteria at 24 hours after admission allowed appropriate therapy to be started on Day 2. Had T2Bacteria had been ordered simultaneously with blood culture, appropriate therapy could have been started on Day 1.

Initial Presentation

A high-risk patient was admitted with pulmonary edema and suspected pneumonia. The patient had a history of multiple myeloma, prostate cancer, and CHF. Blood cultures were obtained, and the patient was started on intravenous antibiotics for coverage of pneumonia.

Evaluation and Treatment Decision

Empiric Therapy: The patient was started on levofloxacin and piperacillin/tazobactam for empiric coverage of pneumonia.

Blood Culture Result: Twenty four hours after admission, the nursing unit was called with a critical result from microbiology: gram-positive cocci in clusters.

Updated Therapy: The physician was notified, and a single dose of vancomycin was ordered.

T2Bacteria Result: The physician was uncertain if the organism might be a contaminating organism such as Staphylococcus epidermidis or a more concerning pathogen such as Staphylococcus aureus. The nurse suggested ordering T2Bacteria, and four hours later, the T2Bacteria resulted as S. aureus prompting the appropriate continued therapy with vancomycin. S. aureus was confirmed by the blood culture result the following morning.

Decision Making Based on T2Bacteria Result

The T2Bacteria Panel was used to detect the presence of S. aureus, allowing appropriate therapy to be initiated one day earlier than using blood culture alone.

Utilizing a Negative T2Bacteria Result

81 year old female admitted with a one-day history of fever, rigors, weakness, and confusion. Blood and urine cultures were ordered as well as IV antibiotics.

Discussion/Decision Making Based on T2Bacteria Result 

At this point in time, the hospital has not adopted T2Bacteria, however, another hospital in their system has. Given the high likelihood that the repeat BCx would be negative, they were asked to draw a blood sample on the day the patient was ready for discharge and send it to the institution that currently utilized the T2Bacteria Panel.

A courier was called and the test was run 4.5 hours after the blood was drawn, and resulted in 3.5 hours with no organisms detected.  The information was relayed to the ordering resident and physician, and the patient was subsequently discharged roughly a day earlier with oral antibiotics.  The clinician noted that even though this was not standard use of this test, it saved a patient a day in the hospital and also potentially spared the patient additional risk of hospital-acquired infections, further confusion, deconditioning, and risk of falls.

Presentation

81 year old female admitted with a one-day history of fever, rigors, weakness, and confusion. Blood and urine cultures were ordered as well as IV antibiotics.

Hospital Course

The patient was started on broad-spectrum IV antibiotics and baseline BCx and UCx grew E. coli.  The patient rapidly defervesced after the initial antibiotics and was de-escalated to IV ceftriaxone and clinically improved. The patient was ready for discharge two days later, though need to wait for repeat BCx drawn that day to show no growth for 48 hours, thus, prolonging their stay an additional two days. It was noted the patient had an identical episode nine years ago, with a very sensitive E. coli in BCx and UCx and was discharged on oral ciprofloxacin.

Candida parapsilosis bloodstream infection1

The T2Candida Panel was used to assess for the presence of disease and continuation of antifungal therapy, despite negative blood cultures.

Discussion


Rapid molecular diagnostics such as T2MR technology may help with prognosis of invasive candidiasis. For our case, the T2Candida Panel was utilized upon follow up to assess clearance of candidemia along with clinical symptoms.

Presentation

A 69-year-old man with history of testicular cancer, chronic kidney disease, anemia, gangrenous gallbladder, status post cholecystectomy, hypertension, hyperlipidemia, type 2 diabetes mellitus, paroxysmal atrial fibrillation, heart failure with reduced ejection fraction and implantable  cardioverter defibrillator (ICD), and aortic valve disease s/p mechanical aortic valve replacement who presented with fatigue, fever, diarrhea, emesis, febrile to 102.3 degree Fahrenheit with a blood pressure of 93/43 mm Hg, heart rate of 64 bpm, and respiratory rate of 18 breaths/min. 

Evaluation and Treatment Decision


Initial Diagnosis: Initially diagnosed with Candida parapsilosis bloodstream infection and treated with liposomal amphotericin B at 5 mg/kg/day. After developing acute kidney injury, therapy was changed to micafungin 150 mg intravenous (IV) daily.


Blood Cultures and Echography: Repeat blood cultures continued to grow Candida parapsilosis 10 days after admission. A trans-esophageal echocardiogram (TEE) revealed fibrin stranding on the mechanical aortic valve. Due to his multiple comorbidities, he was not deemed safe for surgical intervention.


Updated Therapy: Micafungin 150 mg IV daily and fluconazole 400 mg orally daily


Discharge Plan: A peripherally inserted central catheter (PICC) was placed, and the patient was discharged from the hospital to complete micafungin IV for 12 weeks plus fluconazole oral combination therapy.


T2Candida Panel – Initial Result: Six weeks after negative blood cultures, a T2Candida Panel was ordered, which still detected the presence of Candida parapsilosis. However, all repeat fungal blood cultures remained negative, and the patient had improved overall. 


T2Candida Panel – Second Result: 18 weeks after blood cultures became negative, a repeat T2Candida Panel was negative for any Candida species while on chronic suppression with fluconazole.


One year later, the patient currently remains alive and doing well on oral fluconazole suppressive therapy at 200 mg daily.


Decision making based on T2Candida Result


The T2Candida Panel was used to assess for the presence of disease and the continuation of antifungal therapy, despite negative blood cultures.

 

1. Ahuja, Tania, Karen Fong, and Eddie Louie. "Combination antifungal therapy for treatment of Candida parapsilosis prosthetic valve endocarditis and utility of T2Candida Panel®: A case series." IDCases 15 (2019): e00525.

Urinary Tract Infection: Suspected Sepsis

83-year-old male presented to the emergency department with urinary retention.

Had the T2Bacteria test been performed and result been reported immediately after collection, the patient could have been initiated on effective empiric therapy over 24 hours sooner, and P. aeruginosa bacteremia identified over two days earlier.

Discussion

Upon admission, the patient was initially given ceftriaxone for the treatment of suspected urinary tract infection.  At the time of admission, he had blood and urine cultures obtained, and T2Bacteria ordered. At this institution patient selection for T2Bacteria testing was based on elevated lactate and/or procalcitonin in patients presenting to the emergency department with suspected bloodstream infections.

Empiric therapy was chosen to cover E.coli, the most common cause of urinary tract infection. This patient did not present with usual risk factors for P. aeruginosa; thus effective therapy against P. aeruginosa was not initiated until urine cultures demonstrated the growth of P. aeruginosa over 24 hours after admission (T2Bacteria results were not reported as this case was part of an observational study). Blood culture growth with P. aeruginosa was delayed >48 hours after admission.

Presentation

83-year-old male presented to the emergency department with urinary retention. Sepsis was suspected, and the patient was admitted with orders for blood and urine cultures, T2Bacteria, and antibiotics.

Patient Selection Criteria

Lactic acid 3.29

Evaluation and Treatment Decision

Diagnosis: Urinary tract infection

Empiric Therapy: Ceftriaxone

Ceftriaxone was chosen for coverage of common causative gram-negative pathogens of UTIs.

T2Bacteria Panel Result: Positive for P. aeruginosa and negative E. faecium, S. aureus, E. coli, and K. pneumoniae.  

Blood Culture Result: P. aeruginosa (>48 hours after admission)

Urine Culture Result: P. aeruginosa (24 hours after admission)

Decision making based on T2Bacteria Panel Result:

A rapid T2Bacteria result could have allowed for more informed treatment decisions, including the initiation of earlier effective therapy.

Community Acquired Pneumonia

Patient presented to the emergency department with shortness of breath, cough, fever and chills.

A rapid T2Bacteria result could have allowed for more informed treatment decisions, including the initiation of earlier effective therapy over 30 hours sooner.

Discussion

Upon admission, the patient was initially given ceftriaxone and azithromycin for the treatment of suspected community-acquired pneumonia. Due to the patient’s history of COPD, he was at risk for organisms such as MRSA (methicillin-resistant Staphylococcus aureus) in addition to the more common causes of community-acquired pneumonia such as Streptococcus pneumoniae and atypical organisms.

 

At the time of admission, he had blood cultures obtained, and T2Bacteria ordered. At this hospital, patient selection for T2Bacteria testing was based on elevated lactate and/or procalcitonin in patients presenting to the emergency department with suspected bloodstream infections.

Effective therapy against MRSA was not initiated until blood cultures demonstrated the growth of S. aureus over 30 hours after admission (T2Bacteria results were not reported as this case was part of an observational study). Had the T2Bacteria test been performed and result been reported immediately after collection, the patient could have been initiated on effective empiric therapy over 30 hours sooner.

Presentation

A 59-year-old male with a history of rectal cancer and COPD. The patient presented to the emergency department with shortness of breath, cough, fever, and chills. Sepsis was suspected, and the patient was admitted with orders for blood cultures, T2Bacteria, and antibiotics.

Patient Selection Criteria

Lactic acid 2.8 mg/dl

Procalcitonin 59 ng/ml

Evaluation and Treatment Decision

Diagnosis: Community-acquired pneumonia

Empiric Therapy: Ceftriaxone, Azithromycin

Ceftriaxone and azithromycin were chosen for coverage of common causative respiratory pathogens identified in community-acquired pneumonia.

T2Bacteria Result: Positive for S. aureus and negative E. faecium, P. aeruginosa, E. coli, and K. pneumoniae.  

Blood Culture Result: Methicillin-resistant Staphylococcus aureus (36-hour delay in species identification from time of blood culture collection)

Decision making based on T2Bacteria Result

A rapid T2Bacteria result could have allowed for more informed treatment decisions, including the initiation of earlier effective therapy over 30 hours sooner.

Suspected urinary tract infection

91-year-old female presented to the emergency department with several day history of fever, chills, and nausea/vomiting.

Had the T2Bacteria® test been performed and result been reported immediately after collection, the patient could have potentially avoided premature discharge and readmission.

Discussion

Upon presentation to the emergency department, the patient was initially given ceftriaxone for the treatment of suspected urinary tract infection. At the time of admission, she had blood and urine cultures obtained, and T2Bacteria ordered. Patient selection for T2Bacteria testing was based on procalcitonin in at the time of presentation.

The patient was discharged prior to blood culture resulting in positive for growth (T2Bacteria results were not reported as this case was part of an observational study). Had the T2Bacteria test been performed and result been reported immediately after collection, the patient could have potentially avoided premature discharge and readmission.

Presentation

A 91-year-old female presented to the emergency department with several day history of fever, chills, and nausea/vomiting. The patient was admitted with orders for blood cultures, T2Bacteria, urine cultures, and antibiotics.

Patient Selection Criteria

Procalcitonin 1.5 ng/ml in a patient suspected of bloodstream infection.

Evaluation and Treatment Decision

Diagnosis:  Suspected urinary tract infection

Empiric Therapy: Ceftriaxone x 1 dose

Ceftriaxone was chosen for coverage of common causative gram-negative pathogens identified in UTIs.

T2Bacteria Result: Positive for E. coli and negative for S. aureus, E. faecium, P. aeruginosa, and K. pneumoniae.

Blood Culture Result: E. coli on Day 2

Urine Culture Result: E. coli on Day 2

The patient was discharged in the morning of Day 2 prior to the availability of culture results. The patient returned to the ED on the next day with ongoing fever/chills and was readmitted.

Decision making based on T2Bacteria Result

A rapid T2Bacteria result could have allowed for more informed treatment decisions, including the continuation of antibiotic therapy and avoidance of readmission less than 24 hours after her initial premature discharge.

Deep-seated invasive candidiasis in a liver recipient

Patient with insulin-dependent diabetes mellitus, primary sclerosing cholangitis, multiple bacteremic episodes and recent liver transplant was admitted.

In this case, T2Candida® results could have permitted earlier focused therapy and aided with the diagnosis of invasive Candida infection and lead to appropriate antifungal therapy. Unfortunately, the T2Direct Diagnostics results were not in clinical use at the time and not obtained until after patient death.

Discussion

T2Candida retrospectively revealed C. albicans/C. tropicalis, even at the beginning of the process when the patient was asymptomatic. This case highlights the potential advantage of T2Direct Diagnostics aiding in the diagnosis of deep-seated infection in an immunosuppressed patient without confirmed infection, even before the onset of symptoms.

The two key findings were that arteritis and thrombosis of the hepatic graft resulted from an undocumented fungal infection in the explanted liver and that T2Candida was a suitable diagnostic tool for the diagnosis of deep-seated invasive candidiasis in the absence of positive blood culture results.

Presentation

A 57-year-old woman with insulin-dependent diabetes mellitus, primary sclerosing cholangitis, multiple bacteremic episodes, and recent liver transplant was admitted for sudden abdominal pain. After identification of intrahepatic abscesses the patient underwent a second liver transplant. Subsequently, non-purulent inflammatory tissue was observed in the liver with extensive clotting of the portal vein and hepatic artery and generalized hepatic ischemia. In the following hours, the patient developed graft failure, severe coagulopathy, and died.  

Evaluation and Treatment Decision

All of the cultures collected before death, including blood (obtained at admission and repeated 3 times during hospitalization), ascitic fluid at admission, and liver and abdominal tissues during the re-transplantation procedure, were sterile.

Final Diagnosis: Liver abscess

Empiric Therapy (May 31, 2017): Vancomycin, meropenem, caspofungin

T2Candida Panel Result: Retrospective T2MR performed on blood samples obtained on May 27th, May 31st, June 9th, June 16th, and June 26th showed C. albicans/C. tropicalis present in all samples.

Histology Result: Histopathology of explanted liver tissue revealed multiple ischemic areas with abundant filamentous fungal structures in their interior, and C. albicans was identified using multiplex PCR.

Decision making based on T2Candida Result

T2Candida result from May 27th (and subsequent results) could have permitted earlier focused therapy and aided with the diagnosis of invasive Candida infection. Unfortunately, the T2Direct Diagnostics results were not in use clinically and not obtained until after death.

Suspected aspiration pneumonia vs HCAP

Patient presents to the Emergency Department from nursing home with fever, dyspnea, and altered mental status.

Discussion

At the time of admission, this patient had blood cultures obtained, and T2Bacteria ordered. At Piedmont Columbus Regional, patient selection for T2Bacteria testing was based on >2 SIRS criteria PLUS suspected source of infection PLUS hypotension or altered mental status. This patient was positive for 2 of 4 SIRS criteria and had a suspected cause of infection and altered mental state, thus meeting criteria for testing.

Determination of the causative organism for this patient’s infection allowed optimization of the antibiotic regimen within 24 hours of presentation. The patient was not improving on empiric therapy and experienced clinical improvement after the switch from ceftazidime to meropenem. Additionally, clindamycin was discontinued on Day 2 and vancomycin was discontinued on Day 3 allowing for 5 days of therapy to be saved for clindamycin and 4 days of therapy to be saved for vancomycin. The patient continued to improve and was discharged back to the nursing home after meropenem therapy was completed.

Presentation

PS is a 69 y/o M who presented to the Emergency Department from a nursing home with a fever, dyspnea, and altered mental status. His initial lactic acid was 4.5. The treating physician saw him, and sepsis was suspected. PS was admitted with orders for labs, blood cultures, T2Bacteria®, and broad-spectrum antibiotics.

Patient Selection Criteria

SIRS criteria:

  • Temperature: 103.5˚F
  • Heart Rate: 130 bpm
  • Respiratory Rate: 20
  • WBC (initial): 19,920/mm3

Evaluation and Treatment Decision

Suspected aspiration pneumonia vs. HCAP

Empiric Therapy: Vancomycin, Clindamycin, Ceftazidime

T2Bacteria scheduled to result at 2030 on second shift. Result: K. pneumonia (time to result: ~5 hours), result reviewed by ID pharmacist next am

Blood Culture Result: Negative after 5-days incubation

WBC next am on Ceftazidime: 24,950/mm3 (worsening)

Decision making based on T2Bacteria Result

  1. Reviewed internal antibiogram. Changed Ceftazidime to Meropenem based on antibiogram percent susceptibility of 88% vs. 99%.
  2. Discontinue Clindamycin and vancomycin
  3. WBC next am after the switch to Meropenem: 10,960/mm3

 

Suspected Intra-abdominal sepsis

Patient presents with suspected sepsis

Discussion

Upon admission, the patient was initially given the broad spectrum antibiotics linezolid, aztreonam, and metronidazole for the treatment of suspected intra-abdominal sepsis. Due to the patient’s recent healthcare exposure, she was at risk for organisms such as MRSA (methicillin-resistant Staphylococcus aureus) and Pseudomonas aeruginosa in addition to the more common causes of intra-abdominal infection such as enterobacteriaceae and anaerobic organisms. 

At the time of admission, she had blood cultures obtained, and T2Bacteria ordered. At Lee Health patient selection for T2Bacteria testing was based on the NEWS (National Early Warning Score) scoring system. The NEWS score was developed to standardize the approach to detection of clinical deterioration in acutely ill patients in the United Kingdom, and a score of 7 or higher puts the patient in the high-risk category. This patient also was positive for 3 of 4 SIRS criteria and had a qSOFA score of 2, indicating a high risk of mortality.

Due to the negative blood culture (T2Bacteria results were not reported as this case was part of an observational study), the patient remained on empiric therapy for 5 days and then was changed to oral therapy and discharged 2 days later. Had the T2Bacteria result been reported, the patient could have been changed to meropenem to cover the E. coli and P. aeruginosa, allowing discontinuation of aztreonam. Given the S. aureus was negative, linezolid could have been discontinued as well. Discontinuation of these two antibiotics within the first 24 hours of admission would have led to ~$6,000 savings in antibiotic charges, and potentially led to earlier discharge on effective oral therapy.

Presentation

53-year-old immunocompromised, morbidly obese female with a recent history of surgery to drain an intra-abdominal abscess. The patient presented at the emergency department 8 days post-op with fever, chills, and abdominal pain. Sepsis was suspected, and the patient was admitted with orders for blood cultures, T2Bacteria®, and broad-spectrum antibiotics.

Patient Selection Criteria

SIRS criteria:

  • Temperature: 103.4
  • Heart Rate: 133 BP90/62
  • Respiratory Rate: 34
  • WBC: 6,800/mm3
  • NEWS Score: 9
  • QSOFA Score: 2

Evaluation and Treatment Decision

Diagnosis: Suspected Intra-abdominal sepsis

Empiric Therapy: Linezolid, Aztreonam, Metronidazole

Linezolid was chosen for gram-positive coverage due to challenges with vancomycin dosing in obese patients. Aztreonam was chosen for gram-negative coverage due to the patient history of penicillin allergy. Metronidazole was chosen for anaerobic coverage.

T2Bacteria Result: Positive for E. coli and P. aeruginosa and negative for S. aureus, E. faecium, and K. pneumoniae. (SA -, PA + & EC +); T2Bacteria results were not reported as this case was part of an observational study.  

Blood Culture Result: Negative

Decision making based on T2Bacteria Result

The negative S. aureus result meant that the patient did not have MRSA and therefore, linezolid could have been discontinued after the first dose when the T2Bacteria result was available, a 4.5-day reduction in linezolid. The patient’s therapy could have been more targeted gram-negative coverage by switching to meropenem to cover E. coli and P. aeruginosa

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