University of UtahARUP Laboratories Invasive Fungal Infections Identification Matters Patient History A 62 yearold male patient presents to the ER with a 3day fever as his chief complaint ID: 918332
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Slide1
Margaret Powers-Fletcher, Ph.D. University of Utah/ARUP Laboratories
Invasive Fungal
Infections:
Identification
Matters!
Slide2Patient HistoryA 62 year-old male patient presents to the ER with a 3-day fever as his chief complaint.
He develops
skin lesions
over the first few days of admission, which progressively got worse. The patient has a history of acute myeloid leukemia (AML), for which he received a stem cell transplant and chemotherapy.
Photos Courtesy of
University of Utah/ARUP Laboratories
Slide3Opportunistic Pathogens of the Immunocompromised HostBecause of his treatment for AML, the patient had a suppressed immune system.
Immunosuppressed patients are at risk for many infections, which can be caused by primary or opportunistic pathogens.
Primary Pathogens
: those that can infect otherwise healthy individuals.Opportunistic Pathogens: organisms that only infect humans in certain host conditions, such as immunosuppression.
Slide4Skin Biopsy ResultsThe pathology report from the skin biopsy stated there were fungal hyphae invading the blood vessels.
These hyphae were described as being
septated
(walls between cells) with acute angle-branching, with some features being compatible with the fungus Aspergillus.
Photo Courtesy of
University of Utah/ARUP Laboratories
Slide5Microbiology Work-UpSpecimens were submitted for culture to determine if there was a bacterial or fungal etiologic agent causing his symptoms.
Blood was submitted to detect disseminating (spreading throughout the body) organisms.
Tissue from the skin biopsy was submitted to help identify the fungal organism that was seen on the stain from the lesion.
Nucleic acid, antigen, and antibody testing was also performed to help detect infections with viruses and fungi.
Slide6Microbiology Laboratory ResultsAll bacterial and viral test results were negative…
BUT a
fungus
grew in the blood culture bottle and was visible upon Gram stain.The same fungus also grew from the tissue culture
.
Stain of Blood Culture Bottle (10x)
Stain of Blood Culture Bottle (40x)
Photos Courtesy of
University of Utah/ARUP Laboratories
Slide7Medical MycologyFungi are often identified using colony appearance and sexual/asexual reproductive structures that are observed microscopically.
The microbiologist must have a high-level of expertise and experience.
Based on phenotypic analysis, this organism was identified as a
Fusarium species.
Colony Appearance
Microscopic Structures
Photo Credits:
Centers for Disease Control and Prevention
and
Wikimedia
Slide8Diagnosis: FusariosisMany Fusarium species are primarily soil saprophytes or plant pathogens, but certain species can be opportunistic pathogens of humans.
Because of this patient’s immunosuppression, he is at risk for opportunistic infections.
Fusarium
infections, or fusariosis, can be superficial, locally invasive, or disseminated.Because of their ubiquitous nature, however, isolation of Fusarium species in culture may be due environmental contamination.
Therefore, the microbiologist and clinician must work together to interpret the results. Clues for clinically significant results are:
Fungi seen on direct stain of tissue.Site of isolation and the host.
Same fungus from multiple
specimens.
Multiple colonies from same
specimen.
In Tissue
From Blood
Photos: Courtesy of
University of Utah/ARUP
Laboratories and
Centers for Disease Control and
Prevention
Multiple Specimens
Slide9Importance of Mould IdentificationSome fungi may look similar
in tissue stains, but have
very different susceptibility profiles
to different antifungal drugs.Therefore, the microbiologist plays an important role in helping make the correct identification to guide appropriate antifungal therapy.
Slide10Patient OutcomeThe patient’s suppressed immune system put him at risk for invasive fungal disease.
Two different antifungal drugs were given and the patient was monitored closely.
The symptoms, including lesions, improved with no evidence of treatment failure.
The clinical microbiology results were essential in making sure the patient received the appropriate therapy!
A. Michal Stevens, M.D.Infectious Disease Fellow
University of Utah
Created by:
Margaret Powers-Fletcher, Ph.D.,
Medical Microbiology Fellow
University of Utah/ARUP
Laboratories
Slide11Margaret Powers-Fletcher, Ph.D.Dr. Powers-Fletcher is a Fellow in the Medical and Public Health Laboratory Microbiology program at the University of Utah/ARUP Laboratories. Her research has focused primarily on medical mycology, with emphasis on pathogenesis mechanisms, antifungal susceptibility testing, and fungal diagnostic and detection techniques.
Photo Credit:
Margaret Powers-Fletcher, Ph.D