Background
Rapid diagnosis and appropriate treatment is imperative in bacterial sepsis due increasing risk of mortality with every hour without appropriate antibiotic therapy. Atypical infections with fastidious organisms may take more than 4 days to diagnose leading to calls for improved methods for rapidly diagnosing sepsis.
Capnocytophaga canimorsus
is a slow-growing, fastidious gram-negative bacillus which is a common commensal within the mouths of dogs, but rarely cause infections in humans.
C. canimorsus
sepsis risk factors include immunosuppression, alcoholism and elderly age. Here we report on the application of emerging nanopore sequencing methods to rapidly diagnose an atypical case of
C. canimorsus
septic shock.
Case presentation
A 62 year-old female patient was admitted to an intensive care unit with septic shock and multi-organ failure six days after a reported dog bite. Blood cultures were unable to detect a pathogen after 3 days despite observed intracellular bacilli on blood smears. Real-time nanopore sequencing was subsequently employed on whole blood to detect
Capnocytophaga canimorsus
in 19 h. The patient was not immunocompromised and did not have any other known risk factors. Whole-genome sequencing of clinical sample and of the offending dog’s oral swabs showed near-identical
C. canimorsus
genomes. The patient responded to antibiotic treatment and was discharged from hospital 31 days after admission.
Conclusions
Use of real-time nanopore sequencing reduced the time-to-diagnosis of
Capnocytophaga canimorsus
in this case from 6.25 days to 19 h.
Capnocytophaga canimorsus
should be considered in cases of suspected sepsis involving cat or dog contact, irrespective of the patient’s known risk factors.
Electronic supplementary material
The online version of this article (10.1186/s12879-019-4173-2) contains supplementary material, which is available to authorized users.
We describe a young man who initially presented with stroke and febrile illness. He was eventually diagnosed with
Tropheryma whipplei
endocarditis. This is a very rare condition and to the best of our knowledge, this is the first documented case of
T. whipplei
endocarditis in Australia and New Zealand regions. This report aims to increase awareness of clinicians of this very rare but potentially treatable condition. It is reasonable to exclude
T. whipplei
endocarditis when dealing with high-risk patients who are suspected for “culture-negative” endocarditis.
We present a case of Capnocytophaga canimorsus septic shock after a dog bite in an immunocompetent individual, where real-time nanopore metagenomic sequencing characterized the microbial agent within 19 hours, with subsequent confirmation using droplet digital PCR. Oral swabs from the dog demonstrated a nearly-identical C. canimorsus isolate by sequencing.
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