+1 Aspergillus; +++Confusion No Longer

I was extremely fortunate in my ID rotation and some of the rare infections on my list of “would like to see” manifested in hospital during my ID rotation. This included fungal lung infections. The culture was +1 for aspergillus of a lung biopsy and it provided me an opportunity to clarify a burning therapeutic question and that was how to assess these culture results? In a patient with respiratory disease, one of two things could be happening. Firstly, aspergillus is an environmental mold and isolation from sputum or lung tissue biopsy does not necessarily indicate invasive disease of the lung parenchyma. This may be a commensal with no implication in the current clinical status of the patient. Although the sequelae of an untreated invasive or chronic aspergillosis may be serious, the antifungals to treat aspergillus have potentially toxic side effects, serious drug interactions and long durations of treatment. So understanding when and when not to treat is an important part of medication management. I recalled a case early in my residency where a deep sputum culture grew +1 aspergillus however unlike this patient no treatment was recommended. In the end, it came down to careful consideration of the patient specific factors including history, risks and comorbidities.

The Things That Keep You Up at Night…

Once upon a time in pharmacy school, we were introduced to a table of antibiotic susceptibilities. Today, I am picking on cephalosporins for this reason and I roughly quote “these antibiotics appeared to lose activity against gram positive organisms and gain gram negative activity in each new generation…well sort of, but not completely so we leave the “+” sign on the antibiotic spectrum table of activity but it’s more complicated than.” It is indeed more complicated than that. Pathogen (resistance, MICs and intrinsic factors), drug (potency and distribution) and patient factors all need to be taken into consideration. One of my ID rotation goals was to bring some long over due order to this issue by creating a table of predicted susceptibilities based on Bugs and Drugs as a rough guide.

Streptococcal Coverage of Cephalosporins

 

 

 

The Microbiome and Their Not so Welcome Relatives

If you ever you feel alone, don’t! Because you have millions and millions of bacteria that are so so happy you are there!

I still remember this joke from microbiology lab, *sigh* but it takes on a new meaning in ID. So which of our ‘friends’ is causing infection vs. just along for the ride? Staph epidermis may sound inert but with a nephrostomy tube it could be (spoiler alert, was) a recipe for pyelonephritis….

The first two weeks of my ID and Antimicrobial Stewardship rotation have been an eye opener to the wonderful world of infections disease and antibiotic treatments! Working with my preceptor during ID consultants has been both exciting and challenging. The infections we see on a daily basis have included everything from polymicrobial VAP, infective endocarditis with Staphylococcus aureus, urosepsis with mixed Proteus mirabilis and Morganella and a large hematoma infected with group A streptococci…just to name a few. My knowledge of antibiotic selection and treatment durations in these complicated infections has been growing at a super sonic rate. I am quickly realizing that the treatment of infection can follow a dynamic course, which is not always predictable. These patients require close monitoring and meticulous follow-up to prevent recurrence, complications and secondary nosocomial infections. Importantly, the necessity of source control, adequate drug potency and penetration at the site of infection cannot be understated. Patient, organism and antimicrobial specific factors need to be carefully considered when choosing appropriate therapy.

No ePortfolio post would be complete without a progress report. At the end of week two, I am following 11 patients from an ID perspective, which is in line with one of my rotation goals. I continue to work to shorten my assessments in these focused work-ups. I believe having a more in-depth understanding of how to interpret the laboratory C&S results and test panels (including limitations) will be beneficial in decreasing my time to complete a comprehensive work up. Since beginning this rotation, I have a better understanding of where these fit into the clinical picture. An example is how to interpret C. difficle testing results, which is more confusing to clinicians that one might think. Antibodies, toxin A/B and NAT testing, oh my!