Division of Infectious Diseases

Treatment of Osteomyelitis – What’s the Evidence for our Strategies?

New UNMC ID publication alert! #ReadUNMCID

Recently, the newest member of our Division of Infectious Diseases at UNMC/Nebraska Medicine, Dr. Nicolas Cortes-Penfield published an invited review in Open Forum Infectious Diseases entitled: The History of Antibiotic Treatment of Osteomyelitis.  Dr. Cortes-Penfield wrote this summary describing the review article, which was commissioned after he published a comprehensive blog post (on his blog IDJournalClub.com) about the history of osteomyelitis, with a robust twitter response to the topic.

What is the study about?

The impetus for this study was the recently published OVIVA trial, which showed equivalent outcomes with oral versus intravenous antibitoics for bone and joint infections.  This was a large and really well-designed randomized clinical trial – in our minds, one of the best clinical trials ever published in bone and joint infection research.  Yet, we observed that many infectious disease specialists did not feel that OVIVA represented enough evidence to change the way they treat these infections.  So we asked ourselves, “What exactly is the quality of the evidence for the way we’ve been doing things?”

In our study, we laid out some of the most commonly taught tenets of treating bone infections (osteomyelitis) and then conducted a narrative historical literature review reaching back to the beginning of the antibiotic era to try to tease out where these teachings came from and which ones were backed by high quality evidence (like clinical trials) versus simply expert opinion and tradition.

What did the study find?

As we reviewed the literature, we focused on three classical teaching points for osteomyelitis: that certain antibiotics are better for these infections because they concentrate in the bones, that intravenous antibiotics give better results than antibiotics given by mouth, and that osteomyelitis needs to be treated with antibiotics for four to six weeks.

We found that the research on antibiotic bone penetration was heterogenous, and that with the exception of the penicillins and cephalosporins there wasn’t compelling evidence that the antibiotic classes achieve different concentrations in bone.  Moreover, the studies that generated the theory that antibiotics with better bone penetration treated osteomyelitis more effectively were done in animals; we could not find any robust data in people to support this notion.

As for the universal necessity of giving antibiotics intravenously for osteomyelitis, we were surprised to find that many of the first reports of antibiotic treatment of bone and joint infections used oral penicillins and other agents, with excellent results.  Moreover, when retrospective studies and prospective clinical trials compared specific antibiotics head-to-head, the patients given antibiotics by mouth did just as well as those who received antibiotics intravenously.  This was true of multiple studies including both children and adults, and is important because it shows us that the OVIVA study is not the outlier in this body of literature, but rather an extension of what the preponderance of data in people has been telling us all along.

As for the necessary duration of therapy in osteomyelitis, we were surprised by how little evidence we could turn up on this topic.  Again, physicians in those earliest reports often used just a couple of weeks of therapy, and most often let their patients’ conditions (e.g. the presence of fever) guide the duration of antibiotic treatment.  As best we could determine, a chart study of bone and joint infections published in the New England Journal of Medicine, in which the authors reviewed 62 osteomyelitis cases at their hospital to conclude that patients who received at least a month of antibiotics were more likely to respond well to treatment, seems to have originated what is a now universal dogma.  In fact, we located more recent data showing that children with acute osteomyelitis do well with less than three weeks of antibiotic treatment, as well as studies suggest that eight or more weeks of therapy may be better for adults with osteomyelitis and certain high-risk features like ESRD, infection with Methicillin-Resistant Staphylococcus aureus, and undrained paravertebral abscess.  So, what we can say with confidence is that this question hasn’t been adequately studied, and how long a course of antibiotics a patient needs probably depends on who they are.

Why is this study interesting?

This study lays bare the scarcity of data on which several of our current traditions regarding treating osteomyelitis are based.  Medicine is a field with a lot of cultural inertia – which makes sense, in that when you’re making high-stakes decision there’s a natural bias to keep doing what you’ve seen work before and what your mentors told you worked best for them.   So, in order for us as a medical community to embrace evidence-based medicine, we need more than just better clinical science; we need a shift away from reliance on tradition and deference to hierarchies of eminence (i.e.; “That’s always how we’ve done it here”) and toward a culture of skepticism and interrogation of clinical pearls that don’t come with references cited.  We hope this study – whose narrative structure we intended to help the reader grasp the humble origins of some of the clinical dictums they were taught – will do a little to shift the infectious diseases community toward a culture of evidence-based medicine.

What about future research questions?

We could answer this question two ways.  First, with the field of osteomyelitis, some obvious next questions are whether certain antibiotic combinations might be more effective at achieving clinical cure without recurrence (i.e.; the use of adjunctive rifampin, currently undergoing a large randomized controlled trial) and what patient and infection factors identify people with osteomyelitis who will do just as well with less than four weeks of antibiotic therapy, or conversely who would really benefit from longer than six weeks of antibiotics.  Second, there are plenty of other infections with current standards of treatment based in expert opinion that would benefit from the historical narrative review treatment.


 

Meet Jessica Quick, our new ID administrator

We’re excited to welcome Jessica Quick, MBA, to our UNMC ID team as a new administrator!

Why did you choose to come work at UNMC?

UNMC has a wonderful reputation in the community for innovation and growth.  Joining the ID Division gave me the chance to expand my horizons and learn more about the academic portion of practice, along with continuing to be involved in the clinical setting through the Specialty Care Clinic and other ID clinical programs .

What makes you excited about working in ID?

The ID Division is a dynamo – clinical, research, and education.  ID has experienced amazing growth over the last few years.  The faculty numbers continue to increase and ID research is at the forefront of innovation.  We are also expanding our Fellowship and our regional, national, and international reputation.  Though the practice of medicine is very clinical in nature, I hope that I can be a valuable asset on the administrative and business side of the practice.  I expect there will be lots of great changes continuing to emerge from the ID Division over the next few and I am very excited to be part of that.

Tell us something about yourself that is unrelated to medicine.

I love spending time with my family hanging out in the back yard.  We regularly turn on a baseball game and play yard games with the kids.  Our favorite currently is Giant Jenga and Frisbie Golf.

 


 

Tenure-Track Faculty Position in Oncology-ID Open for Applications!

The University of Nebraska Medical Center (UNMC) is pleased to announce the opening of a tenure-track faculty position in Oncology-ID in the Division of Infectious Diseases, Department of Internal Medicine. Successful candidates will hold an academic appointment at the assistant or associate professor level and will be employed by UNMC and Nebraska Medicine. Candidates should be Board Eligible/Certified in Infectious Diseases. Specialized training or experience in immunocompromised host ID is desirable.

A generous compensation package with salary commensurate with experience will be offered. Candidates should have an enthusiasm for patient care, teaching, and clinical research. Generous protected time and support are available in order to conduct collaborative clinical research and achieve the goals of the program.

Opportunity Highlights:

  • Join a team of professionals – including ID Physicians, advanced practice providers, and clinical and research support personnel – dedicated to the care of patients who have infectious diseases complications associated with stem cell transplantation or treatment of underlying hematologic or solid tumor malignancies.
  • Provide care for both inpatients and outpatients in the state-of-the-art Fred & Pamela Buffett Cancer Center – newly opened in 2017; collaborate with colleagues in solid organ transplant ID.
  • Explore abundant clinical and translational research opportunities.
  • Teach medical students, residents, and ID fellows on the Oncology ID consult service

The applicant will fully participate in the clinical, teaching, and research programs of the Infectious Diseases Division – a vibrant and growing division made up of 23 ID faculty with numerous close associations with other clinical and basic science departments. The interested applicant is encouraged to learn more about UNMC ID at our website: and the UNMC ID blog.

Interested candidates should apply online.  Questions may be directed to Jessica Quick at jessica.quick@unmc.edu.


 

How Clean is the Hub?

New UNMC ID publication alert! #ReadUNMCID

Recently, several members of the Division of Infectious Diseases at UNMC/Nebraska Medicine published a study in American Journal of Infection Control (AJIC) entitled: Microbial colonization of intravascular catheter connectors in hospitalized patients. Drs. Richard Hankins (former ID fellow, class of 2019), and Kelly Cawcutt (Associate Medical Director of Infection Control) are the lead and senior authors on this study.  Dr. Hankins wrote this summary describing their study.

What is the study about?

The infection control team at Nebraska Medicine is constantly evaluating for methods to reduce central line associated blood stream infections.  In 2016 we were evaluating whether our catheter connectors could have a role contributing to central line associated blood stream infections.  At the time we were using a split septum catheter connector (Lever Lock, Becton Dickinson) and due to the open nature of the catheter connector diaphragm, we were concerned that this could become colonized, and then bacteria could spread down the IV tubing leading to a blood stream infection.

We then set out to assess the colonization of the split septum catheter connectors of both central and peripheral lines at Nebraska Medicine on active infusions.  Catheter connectors were assessed both in intensive care units as well as the general medical/surgical wards. We avoided sampling in catheter connectors with antibiotics running or what was deemed a critical infusion (pressors).  The infusion would be paused and the catheter connector diaphragm was then placed directly onto an agar place.  We would do 4 impressions onto an agar plate of the same diaphragm, and due to the size of the agar plate, we were able to do 4 separate catheter connectors on each agar plate.  After incubating each plate for 48-72 hours we assessed for microbial growth.  We found that of the 234 catheter connectors we evaluated, 98 of them had microbial growth (41.9%).  This was deemed excessively high to the point that the hospital switch from split septum catheter connectors to the luer lock catheter connector (Max Zero, Becton Dickinson) , and simultaneously instituted the alcohol infused port protector (Curos, 3M).  After the switch was made, waited three months for the nursing staff to become used to working with the new catheter connectors, and then repeated the study.

What did the study find?

We found in the first phase of the study that the split septum catheter connectors were colonized 41.9% of the time.  When we performed the second phase of the study assessing the luer lock catheter connectors with the port protector caps. In the second phase of the study with the luer lock connectors we sampled 243 catheter connectors and found that 56 of them showed microbial growth (23.1 %).  Multiple logistic regression was used and determined that that this was a significant difference, even after adjusting for the difference in locations and line type.

Why is this study interesting?

This study was fascinating given how high the rates of colonization were on active infusions in the hospital.   Given such high rates of colonization we were surprised that we didn’t have even more blood stream infections. There have been other studies regarding catheter hub colonization although this was the first to our knowledge to compare two separate catheter hubs, and more so a comparison of active infusions in a clinical setting.  The alcoholic port protectors were instituted simultaneously with the luer lock connector, so it is difficult to say whether the effect was completely from a change in the catheter connectors.  We were still shocked the rate of colonization remaining fairly high at 23.1%, even with the luer lock connectors.

What about future research questions?

There is limited data showing a correlation between catheter hub colonization and the same bacteria causing blood stream infections, but further research could evaluate this correlation.  There also remains opportunity to try to further reduce microbial colonization given that even after our intervention the microbial colonization still remained elevated, although significantly reduced from what it was prior.

Citation:

Hankins, Richard, O. Denisa Majorant, Mark E. Rupp, R. Jennifer Cavalieri, Paul D. Fey, Elizabeth Lyden, and Kelly A. Cawcutt. “Microbial colonization of intravascular catheter connectors in hospitalized patients.” American Journal of Infection Control (2019).

Tenure-Track Faculty Position in Solid Organ Transplant ID Open for Applications!

The University of Nebraska Medical Center (UNMC) is pleased to announce the opening of a tenure-track faculty position in Solid Organ Transplant Infectious Diseases in the Division of Infectious Diseases, Department of Internal Medicine. Successful candidates will hold an academic appointment at the assistant or associate professor level and will be employed by UNMC and Nebraska Medicine. Candidates should be Board Eligible/Certified in Infectious Diseases. Specialized training or experience in immunocompromised host ID is desirable.

A generous compensation package with salary commensurate with experience will be offered. Candidates should have an enthusiasm for patient care, teaching, and clinical research. Generous protected time and support are available in order to conduct collaborative clinical research and achieve the goals of the program.

Opportunity Highlights:

– Join a team of professionals – including ID Physicians, advanced practice providers, and clinical and research support personnel – dedicated to the care of patients who have infectious diseases complications associated with solid organ transplantations.

– Provide ID care for recipients of liver, kidney, heart, lung, pancreas and multi-visceral/small bowel transplants.

– Collaborate with a multi-disciplinary team in our Multi-Organ Transplant Clinic.

– Conduct clinical and translational research.

The applicant will fully participate in the clinical, teaching, and research programs of the Infectious Diseases Division – a vibrant and growing division made up of 23 ID faculty with numerous close associations with other clinical and basic science departments. The interested applicant is encouraged to learn more about UNMC ID at our website and the UNMC ID blog.

Interested candidates should apply online.  Questions may be directed to Jessica Quick at jessica.quick@unmc.edu.

 


 

Going Viral with West Nile  

As we get further into the summer, we are yet again nearing West Nile Virus season, and there are starting to be a few cases reported nationwide. Our senior ID fellow Dr. Lindsey Rearigh wrote an article outlining what to expect with West Nile Virus, how it is transmitted, diagnosed, and treated. 

West Nile Virus (WNV) is a mosquito born illness that made its way to the United States in 1999.  The majority of cases are reported in the late summer, peaking from mid- August to September. Although WNV infections have been seen in all the contiguous United States, Nebraska is commonly at the epicenter for cases each year. In fact, Nebraska led the 2018 seasons with 251 total cases reported at the end of the year, including 124 neuroinvasive cases.

In general, birds harbor the virus and transmit the virus to mosquitos after the mosquitos has feed on the infected bird. WNV is most commonly spread to humans by the bite of a mosquito although can rarely be spread through blood transfusions and organ transplantation as well. WNV has not been demonstrated to spread directly from human to human via touch, saliva or other bodily fluids.

Symptoms range from asymptomatic to fevers and neurologic manifestations including meningitis, encephalitis and even flaccid paralysis. About 80% of people affected will be asymptomatic with only about one in 150 cases manifesting as neuroinvasive disease. Symptom onset is seen approximately 2 to 6 days following mosquito exposure, but can be seen up to 2 weeks after a bite in the immunocompromised population.  If symptomatic, the elderly are generally more severely affected with a demonstrated increased overall incidence of neuroinvasive disease peaking for those greater than seventy years old.

Diagnosis is typically made via serologic testing for immunoglobulins in the blood. If neuroinvasive disease is suspected cerebral spinal fluid (CSF) should be collected and tested for the immunoglobulins as well. IgM for WNV is usually detectable within 3 to 8 days from illness onset and can stay positive up to 30 to 90 days after initially detected, sometimes longer. IgG for WNV will persist for even longer than IgM even up to years after initially positive, meaning testing positive for IgG alone would not be sufficient evidence to diagnosis an acute infection either in the blood or in the CSF.

Treatment is aimed at symptomatic care with therapies such as high dose steroids and plasmapheresis demonstrating variable improvement in patient outcomes. Time to complete recovery is variable from weeks to months in some cases, and can even leave some permanent neurological affects in the patients most severely affected. There is no vaccination available, so education on prevention is of the utmost importance. Avoidance is key, staying indoors at dawn and dusk when mosquito activity is high and if you are outdoors during those times, wearing long pants and sleeves are recommended. Insect repellant approved by the EPA is also important in efforts to avoid mosquito bites and in general is recommended to be worn over clothing for maximal effect.

Want to find out exactly how many cases of WNV have been reported across the country? Check out the statistics here and here.

The CDC also has a comprehensive resource for more information on WNV.

New Faculty Spotlight – Dr. Nicolas Cortes-Penfield

Tell us about the position you are starting?

I’m joining the Infectious Diseases Division as an Assistant Professor of Medicine and Medical Director of UNMC’s Outpatient Parenteral Antimicrobial Therapy (OPAT) program.  My clinical practice will be primarily devoted to seeing patients on the Orthopedic Infectious Diseases hospital service, meaning I’ll work with orthopedic surgeons at Nebraska Medicine and Ortho Nebraska to treat patients who have infections involving bones, joints, and implanted orthopedic devices (e.g. artificial knees and hips).  I will also see patients on the General Infectious Disease hospital service, which cares for hospitalized patients with a wide range of infections and symptoms suggesting infection.  In the outpatient clinic, I will primarily be following up with patients seen by Orthopedic Infectious Diseases in the hospital to monitor and continue their treatment.

As the Medical Director of our OPAT program, I will help ensure that patients who need to continue antimicrobial therapy after leaving the hospital receive the drug(s) best suited for their individual situations.  When patients leave the hospital we try to give antimicrobials by mouth instead of intravenously whenever possible, because oral antimicrobials are often equally effective, less bothersome to administer, less costly for our patients, and avoid the risks and discomfort of having an intravenous line at home.  That said, some patients have infections with organisms that cannot be treated with oral antibiotics, or have particularly severe infections that may respond better to intravenous therapy.  For these people, my job will be to help ensure they receive the correct dose and duration of intravenous antimicrobials, receive appropriate safety monitoring bloodwork while on therapy, and have their intravenous lines removed promptly after completing their courses of treatment.

Background:

I was born and raised in Austin, Texas and completed my undergraduate education at The University of Texas at Austin. After graduating from UT-Austin, I went on to complete medical school, residency in Internal Medicine, and clinical and research fellowships in Infectious Diseases at the Baylor College of Medicine in Houston, Texas.  In 2019 I brought my family to Omaha to join the Division of Infectious Diseases at the University of Nebraska Medical Center.

Why UNMC?

I knew that I wanted to stay in academic medicine and build a career focused on research and medical education. Interviewing at UNMC, what struck me most was the friendly and enthusiastic demeanor of all of my prospective colleagues.  It was clear to me that the other junior faculty in the ID section felt supported in their varied career pursuits – clinical service, research, education, administration, etc – and were satisfied with their work/life balance.  I also saw the Orthopedic Infectious Diseases position as a wonderful opportunity to develop expertise in a new, important, and rapidly growing niche within the field of Infectious Diseases.

Something interesting about me not related to medicine:  I am a classically-trained saxophonist and recorded with the UT Saxophone Choir in college.  I’m fascinated by the microorganisms that live all around us and on weekends can often be found tinkering with them via baking, home brewing, working in our backyard garden or pond or compost pile, etcetera.

UNMC Highlights Women in Science

As a medical student, I feel fortunate to be at UNMC, which values and supports women in medicine.  One of the greatest examples of this empowerment championed is a program held this year called “UNMC’s Women in Science: Our Voices, Our Stories.” This event – sponsored by the McGoogan Library of Medicine, the Women’s Mentoring Group, and the UNMC Office of Faculty Development – consisted of a panel of impressive women at UNMC who shared their advice for seeking mentorship, identifying and taking advantage of opportunities, and advocating for oneself.  The presenters included:

  • Jasmine Marcelin, M.D., assistant professor, infectious diseases, associate medical director, Antimicrobial Stewardship Program, UNMC Division of Infectious Diseases
  • Amber Donnelly, Ph.D., professor and director of cytotechnology education, UNMC College of Allied Health Professions
  • Ashley Wysong, M.D., chair of the UNMC Department of Dermatology

We are so proud that Dr. Marcelin participated in this event! Dr. Marcelin’s story of finding mentors who inspired her to follow in their footsteps particularly resonated with me.  I have benefited so much from mentors who have taken time to talk to me about their careers, guide me through the complexities of getting to medical school, and help me become the woman I am now.  Being surrounded by strong and thoughtful women has given me living examples of who I can be in the future.

You can watch the panel presentation here.


 

Pharm2Exam Table: What is persistent MRSA bacteremia and how is it treated?

The following is a clinical review written by Ashleigh Grammar, PharmD, a recent graduate of the UNMC College of Pharmacy, and supervised by Scott Bergman PharmD FIDSA, Clinical Pharmacy Coordinator of Nebraska Medicine Antimicrobial Stewardship Program (@bergmanscott)

What is persistent MRSA bacteremia and how is it treated?

Methicillin-resistant Staphyloccous aureus (MRSA) (photo credit: CDC Public Health Image Library) is a bacteria that can cause a wide variety of infections, including skin or soft tissue infections and bloodstream infections (bacteremia). The Centers for Disease Control (CDC) categorize MRSA as a serious threat (1). Although vancomycin has been a reliable antibiotic to treat MRSA for decades, severe infections from it are still difficult to cure. Current MRSA bacteremia practice guidelines by the Infectious Disease Society of America (IDSA) recommend the use of vancomycin or daptomycin as first-line treatment options for bacteremia (2). Concern arises, however, when bacteremia continues despite the use of these agents. IDSA defines persistent MRSA bacteremia as blood cultures that remain positive after 7 days of effective therapy (2). A study conducted by Cosgrove et al found mortality rates as high as 60% from MRSA bacteremia. Changes in therapy or combination therapy may be necessary despite the limited data (3).

An important step in persistent MRSA bacteremia treatment is identifying all possible sources of infection and obtaining source control through drainage or surgical debridement (3). The IDSA guidelines do not define an optimal treatment regimen for persistent bacteremia. An assessment of the patient’s clinical status around day 7 of therapy is reasonable and should help determine if a change in therapy is warranted. If first-line therapy fails, IDSA guidelines recommend a change in therapy rather than adding an additional agent. Recommendations include high-dose daptomycin at 10 mg/kg daily, if susceptible, in combination with another agent. The second agent could include gentamicin, rifampin, linezolid, sulfamethoxazole-trimethoprim, or a beta-lactam. If there is reduced susceptibility to vancomycin or daptomycin, guidelines suggest sulfamethoxazole-trimethoprim, linezolid, or televancin. These agents could be used alone or in combination with another antibiotic (2). A preferred regimen for persistent bacteremia, however, has yet to be established as most data is only available from case reports or series.

Daptomycin is a cyclic lipopeptide antibiotic that exhibits bactericidal activity against Gram-positive bacteria by inserting its lipophilic tail into the bacterial cell membrane which causes rapid depolarization. In vitro data suggests a synergistic relationship between daptomycin and other antibiotics providing an advantage in persistent MRSA bacteremia. The addition of a beta-lactam to daptomycin improves daptomycin binding to the cell membrane leading to an increase in net cell membrane surface charge and ultimately cell death. A “see-saw effect” also occurs when daptomycin is in combination with an antistaphylococcal beta-lactam where a reduction in daptomycin susceptibility provides an increase in antistaphylococcal susceptibility (3). One case series of 7 patients that were treated with daptomycin 8-10 mg/kg daily plus either nafcillin or oxacillin 2 grams every 4 hours, after failing vancomycin, had blood sterilization within 24-48 hours (4). Adding an antistaphylococcal beta-lactam to daptomycin is a reasonable option when treating persistent MRSA bacteremia.

Similar to the antistaphylococcal penicillins, ceftaroline has also demonstrated a synergistic relationship when added to daptomycin. Ceftaroline, however, provides further benefit by its natural activity against MRSA, vancomycin resistant strains, and daptomycin non-susceptible Staphylococcus aureus. A multi-centered, 26 patient case series reported 96% of patients had clear blood cultures in an average of 2 days after initiation of daptomycin 6-10 mg/kg daily plus ceftaroline 400-600 mg every 8 to 12 hours (5). A recent clinical study of MRSA bacteremia was terminated early due to a significant difference in the mortality rate of daptomycin plus ceftaroline (0%) compared to standard monotherapy (26%), which was mainly vancomycin. Although more data is needed, daptomycin plus ceftaroline has promising results and is an attractive option for salvage therapy in persistent bacteremia.

Another potential option for persistent bacteremia is the addition of sulfamethoxazole-trimethoprim. Combination therapy of daptomycin and sulfamethoxazole-trimethoprim has demonstrated in vitro synergy by increased inhibition of folate synthesis, although the exact mechanism is unknown. The combination did show greater bactericidal activity than either agent alone (7). Two case reports acknowledged successful treatment of a daptomycin non-susceptible bacteremia with daptomycin 10 mg/kg daily plus sulfamethoxazole-trimethoprim 8 mg/kg daily divided every 8 hours (8). In addition, a case series of 26 patients with MRSA bacteremia caused by bone and joint infections identified 24 out of 26 patients that had microbiological eradication in an average of 2.5 days after combination therapy with daptomycin and sulfamethoxazole-trimethoprim (9). This series suggests a potential benefit of this combination in patients that specifically have persistent MRSA bacteremia due to a bone or joint infection.

Although linezolid is an option for S. aureus bacteremia, it is not FDA approved and is often not the preferred agent due to its bacteriostatic activity and large volume of distribution. Combination therapies that add linezolid, however, have shown some benefit in persistent bacteremia. In vitro data has shown a combination of linezolid with daptomycin was more effective than either agent alone.10 Few clinical data have shown this benefit. Two studies demonstrated a 30 day mortality benefit of a linezolid based-regimen over adding another agent to vancomcin (11,12). Although there is a risk of toxicities associated with a prolonged duration of therapy, linezolid based regimens could be used for salvage therapy in persistent bacteremia.

Lastly, rifampin in combination with daptomycin for persistent bacteremia potentially provides additional benefit due to the ability of rifampin to target biofilm. It should be noted that addition of rifampin for bacteremia with endocarditis is not routinely considered because of rapid development of rifampin resistance by circulating S. aureus. Patients with bacteremia due to an infected prosthetic device or bone infections may have more success with this regimen (3). A case series of 12 patients with osteomyelitis or other joint infections showed clinical cure in 10 of the patients that received high dose daptomycin plus rifampin 300-600 mg daily (13). These cases provide another option in salvage therapy for those patients that have an infection with biofilm.

Conclusion

Many combination antibiotic regimens have been shown to be successful in patients that have MRSA bacteremia lasting more than 7 days. Daptomycin-based combinations seem promising. However, the lack of randomized controlled trials and comparative studies has made choosing the most appropriate regimen difficult. The patient’s clinical condition, ability to obtain source control, and results of susceptibility testing should determine when and if a modification to the standard antibiotic therapy is indicated. Because of the significant burden of persistent MRSA bacteremia, antibiotic therapy is warranted for at least 6 weeks. Although a combination regimen is likely not necessary for the full course of therapy, timing of antibiotic de-escalations is also not well studied. Eradication of infection, source control and improvement in the patient’s clinical condition can provide insight as to when de-escalation may be appropriate.

References
1. Centers for Disease Control and Prevention. Antibiotic resistance threats in the United States, 2013. http://www.cdc.gov/drugresistance/threat-report-2013/index.html. Accessed February 16, 2019.
2. Liu C, Bayer A, Cosgrove SE, et al. Clinical practice guidelines by the Infectious Diseases Society of America for the treatment of methicillin‐resistant Staphylococcus aureus infections in adults and children. Clin Infect Dis. 2011;52:1‐38.
3. Lewis PO, Heil EL, Covert KL, Cluck DB. Treatment strategies for persistent methicillin-resistant staphylococcus aureus bacteraemia. J Clin Pharm Ther. 2018;43(5):614-625.
4. Dhand A, Bayer AS, Pogliano J, et al. Use of antistaphylococcal β‐lactams to increase daptomycin activity in eradicating persistent bacteremia due to methicillin‐resistant Staphylococcus aureus: role of enhanced daptomycin binding. Clin Infect Dis. 2011;53:158‐163.
5. Sakoulas G, Moise PA, Casapao AM, et al. Antimicrobial salvage therapy for persistent staphylococcal bacteremia using daptomycin plus ceftaroline. Clin Ther. 2014;36:1317‐1333.
6. Geriak M, Haddad F, Rizvi K, et al. Clinical data on daptomycin plus ceftaroline versus standard of care monotherapy in the treatment of methicillin-resistant Staphylococcus aureus bacteremia. Antimicrob Agents Chemother. 2019 [ePub ahead of Print]
7. Dhand, Abhay et al. Daptomycin in combination with other antibiotics for the treatment of complicated methicillin-resistant Staphylococcus aureus bacteremia. Clin Ther. 2014; 36:1303-1316.
8. Avery LM, Steed ME, Woodruff AE, et al. Daptomycin non‐susceptible vancomycin‐intermediate Staphylococcus aureus vertebral osteomyelitis cases complicated by bacteremia treated with high‐dose daptomycin and trimethoprim‐sulfamethoxazole. Antimicrob Agents Chemother. 2012;56:5990‐5993.
9. Claeys KC, Smith JR, Casapao AM, et al. Impact of the combination of daptomycin and trimethoprim‐sulfamethoxazole on clinical outcomes in methicillin‐resistant Staphylococcus aureus infections. Antimicrob Agents Chemother. 2015;59:1969‐1976.
10. Parra-Ruiz J, Bravo-Molina A, Peña-Monje A, et al; Activity of linezolid and high-dose daptomycin, alone or in combination, in an in vitro model of Staphylococcus aureus biofilm. Journal of Antimicrobial Chemotherapy. 2012; 67(11):2682–2685.
11. Jang HC, Kim SH, Kim KH, et al. Salvage treatment for persistent methicillin‐resistant Staphylococcus aureus bacteremia: efficacy of linezolid with or without carbapenem. Clin Infect Dis. 2009;49:395‐40.
12. Park HJ, Kim SH, Kim MJ, et al. Efficacy of linezolid‐based salvage therapy compared with glycopeptide‐based therapy in patients with persistent methicillin‐resistant Staphylococcus aureus bacteremia. J Infect. 2012;65:505‐512.
13. Rose WE, Berti AD, Hatch JB, Maki DG. Relationship of in vitro synergy and treatment outcome with daptomycin plus rifampin in patients with invasive methicillin‐resistant Staphylococcus aureus infections. Antimicrob Agents Chemother. 2013;57:3450‐3452.

Placing PICCs for Antibiotics – Potential Undue Risks May Outweight Benefits

PICC placement is common practice for intravenous (IV) antibiotic needs, however, we may be inadvertently placing certain patients at higher risks for complications. A recent study by Paje et al assessed the frequency of PICC placement among patients with CKD stage 3b or greater, a practice discordant with current guidelines. This prospective study included data from over 20,000 adult patients across 52 hospitals participating in the Michigan Hospital Medicine Safety Consortium between 2013 and 2016. The most common indication for PICC placement was for IV antibiotics (37.6%). Of patients with PICCs, 23.1% had CKD stage 3b or greater, with increased likelihood of PICC placement in the setting of CKD within the ICU as compared to the wards (32.1% vs 18.9%, respectively). Further, most PICC lines placed in patients with CKD were removed prior to hospital discharge (67.2%), with 25.8% of these lines having an indwell time of less than 5 days. 17.8% of all PICCs developed complications, with higher rates among those in the ICU and those with CKD. This study is incredibly important as it highlights the need to assess potential risks of placing a PICC, in addition to the need for IV antibiotics, particularly among those with CKD. The high rate of PICC placement among CKD patients limits their future potential for AV fistula placement, the lowest risk hemodialysis access for CLABSI and other complications. Further, the short duration of indwell time in PICCs suggests potential alternative IV access, or potential treatment options, could have been pursued. There is great opportunity for the ID community to improve vascular access device choice, in concordance with current guidelines, among CKD patients requiring antibiotics.

Content originally posted in the IDSA Journal club. Written by Dr. Kelly Cawcutt.