Capnocytophaga canimorsus Meningitis: Diagnosis Using Polymerase Chain Reaction Testing and Systematic Review of the Literature

Abstract

Introduction Capnocytophaga canimorsus infections are associated with dog bites, especially in asplenic or immunocompromised patients, and typically manifest as sepsis and/or bacteremia. Meningitis has been rarely described, and its diagnosis may be delayed due to poor or slow growth using traditional culture techniques. We provide our experience using polymerase chain reaction (PCR) to establish the diagnosis and perform a comprehensive review of C. canimorsus meningitis cases to provide summary data on the clinical manifestations, diagnosis, and outcomes of this unusual infection. Methods A systematic review of the peer-reviewed English literature (PubMed, Embase, Ovid Medline) from January 1966 to March 2018 was conducted to identify cases of C. canimorsus meningitis. Data collected included demographics, risk factors, cerebrospinal fluid (CSF) findings, PCR results, treatments, and outcomes. Descriptive statistics are presented as numbers (percentages) and medians (ranges). Results A total of 37 patients were reviewed with a median age of 63 years (12 days to 83 years) with a male predominance (76%). A relatively low proportion had an immunocompromised state (16% splenectomy and 5% steroid use); the most common risk factor was alcoholism (19%). Fifty-nine percent reported a dog bite (all within ≤ 14 days prior to presentation), while 22% reported a non-bite dog exposure, 3% reported cat bite, and 3% reported both dog and cat exposures; 11% reported no animal contact. CSF parameters included a median white count of 1024 cells/mm 3 , 81% had neutrophilic predominance, median protein of 190 mg/dl, and median glucose CSF/serum ratio 0.23. In 54% of cases, blood cultures were positive for C. canimorsus (median, 4 days) and 70% had positive CSF cultures (median, 5 days). PCR established the diagnosis in eight (22%) cases. Antibiotic therapy was given for a median of 15 days (range, 7 to 42 days). Prognosis was overall favorable with only one (3%) death reported and adverse neurologic and/or physical sequelae in 19% of the survivors. Conclusion C. canimorsus meningitis is a rare but increasingly important clinical entity occurring in patients of all ages, typically after dog exposure. While classically considered an infection among immunocompromised patients, most cases have occurred in previously healthy, immunocompetent persons. Diagnosis may be rapidly established by PCR, and this test should be considered in culture-negative cases with associated exposures. Outcome was generally favorable after a median antibiotic duration of 15 days.

Mycotic aortic aneurysm due to Capnocytophaga species infection treated non-surgically

“…Patients with C. canimorsus can present with septic shock, disseminated intravascular coagulation, multiorgan failure, meningitis, acute respiratory distress syndrome and uncommonly with a mycotic aneurysm [ 1 , 3 , 4 ]. Severe Capnocytophaga infections are often treated with a beta-lactam/beta-lactamase or a carbapenem.…”

Capnocytophaga canimorsus meningitis diagnosed using next- generation sequencing of microbial cell-free DNA

“…C. canimorsus meningitis is frequently caused by exposure to dog or cat bites and occurs more commonly in immunocompromised males around the age of 60. It classically presents with fever, altered mentation, headache, photophobia and neck stiffness, but other symptoms such as seizures, fatigue and hearing loss have also been reported [ 4 ]. Our patient did not have any immunocompromising risk factors and likely acquired the infection after the dog bite.…”

An Infected Arterial Aneurysm and a Dog Bite: Think at Capnocytophaga canimorsus!

“… 15 Polymerase chain reaction (PCR) and sequencing of the 16S ribosomal RNA (rRNA) is sometimes useful for identifying C. canimorsus . 21 The diagnosis should be made in cases of endocarditis or joint infections with negative cultures and contact with an animal. 8 , 13 The slow growth of this organism may also result in difficulty performing antimicrobial susceptibility testing.…”