[Fulminant sepsis due to Capnocytophaga canimorsus: Diagnosis by matrix-assisted laser desorption/ionization-time of flight mass spectrometry]

The Great pretender: the first case of septic shock due to Capnocytophaga canimorsus in Sardinia. A Case report and review of the literature

Capnocytophaga canimorsus (C. canimorsus) is an emerging pathogen in critical care. C. canimorsus is a Gram-negative bacillus, commonly isolated as a commensal microorganism of the oral flora of healthy dogs and cats. A 63-year-old woman came to the emergency department with fever, chills, and malaise 2 days after a minor dog bite. After admission to the medicine ward, she developed respiratory failure and livedo reticularis. In the intensive care unit (ICU), she presented full-blown septic shock with thrombocytopenia, coagulopathy, severe acute kidney injury, and liver injury. We describe the first case of septic shock with Multiple Organ Dysfunction Syndrome related to Capnocytophaga canimorsus infection in Sardinia and its treatment in a tertiary hospital ICU. We also review recent literature on the relevance of C. canimorsus in human disease and critical illness.

A case of septic arthritis caused by Capnocytophaga canimorsus in an HIV patient

Invasive infections caused by Capnocytophaga canimorsus, a Gram-negative rod found in the oral cavity of healthy dogs and cats, are rare but they are increasing worldwide. We report a case of septic arthritis in a native knee joint due to this micro-organism. A 57-year-old man, with a well-controlled chronic HIV infection, attended the Emergency Department because of left knee pain and shivering without measured fever. A knee arthrocentesis and a computed tomography scan were performed, revealing septic arthritis with collections in the left leg posterior musculature. He was admitted to the Infectious Diseases Department for antibiotic treatment. Initial synovial fluid was inoculated in blood culture bottles, and the anaerobic one was positive after 63 h. Gram stain revealed fusiform Gram-negative rods, identified as C. canimorsus by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF) directly from the bottle. Identification was confirmed by 16S rRNA sequencing and serotyping was performed by PCR, with serovar A as the outcome. Due to an unfavourable clinical course, the patient required two surgical cleanings and after appropriate antibiotic treatment he was discharged 2 months later.

Gemella morbillorum- and Capnocytophaga sp.-Related Mycotic Thoracic Aortic Aneurysm and Mediastinal Abscess: An Unusual Case Report, a Treatment Challenge, and a Review of Literature

A thoracic mycotic aortic aneurysm is an uncommon entity that can complicate mediastinal abscesses. Gemella morbillorum and Capnocytophaga sp. are oral bacteria that are very rarely encountered in this setting, especially when occurring together and with other organisms, posing a difficult treatment challenge per the available guidelines and sensitivities. We present in detail this interesting case of a multi-organism mediastinal abscess and thoracic mycotic aortic aneurysm after a previous esophagogastroduodenoscopic procedure in a 51-year-old female with known achalasia who presented with upper abdominal pain, including a successful surgical and antibiotic treatment regimen and a literature review of the involved topics.

Capnocytophaga canimorsus - a potent pathogen in immunocompetent humans - systematic review and retrospective observational study of case reports

Purpose: Severe and fatal Capnocytophaga canimorsus infection has been described in immunocompromised patients. Data of C. canimorsus infection in immunocompetent and risk factors of severe courses are missing. Our aims were to describe the epidemiology of C. canimorsus infection and to identify potential risk factors of sepsis and fatal outcome.Methods: Observational study and systematic review of all cases reported in immunocompetent subjects between 2002 and 2019.Results: A total of 128 cases of C. canimorsus infection in immunocompetent individuals were reported. Male gender comprised 74.2%, the median age was 58 years and 47.7% were admitted with sepsis. Case-fatality rate was 29.7% and especially high in septic patients (55.7%). Transmission by bite (OR = 2.37, 95% CI: 1.05-6.52) and incubation time ≤3 d (OR = 7.98; 95% CI: 2.33-27.34) were identified as risk factors of sepsis on admission, and early wound cleansing as protective (OR = 0.42; 95% CI: 0.14-0.96). Sepsis (OR = 23.67; 95% CI: 2.85-197.89) and septic shock (OR = 45.50; 95% CI: 3.08-676.55) were risk factors of fatal outcome, whereas early wound cleansing (OR = 0.05; 95% CI: 0.01-0.72), initial penicillin therapy with beta-lactamase inhibitors (OR = 0.48; 95% CI: 0.16-0.92) and surgical removal of infectious focus (OR = 0.38; 95% CI: 0.06-0.95) were protective factors.Conclusions: Immunocompetent patients with C. canimorsus infection frequently develop sepsis. A shorter incubation period in cases of sepsis might be related to higher infectious dose. Fatal outcome may be prevented by early wound cleansing, initial use of penicillins in combination with beta-lactamase inhibitors and surgical removal of an infectious focus.

Oral Bacterial Infections: Diagnosis and Management

The human oral cavity contains more than 500 different bacterial species. These organisms belong to several phyla including Bacteroidetes, Firmicutes, Tenericutes, Actinobacteria, Proteobacteria, Euryarchaeota, Chlamydiae, and Spirochaetes. Many of these have the ability to colonize the gingival crevices and the outer surface of the tooth forming biofilms often leading to dental plaque formation. These bacteria produce acid that erode teeth causing cavities or infections. The diagnosis of these infections is often clinical and antibiotics are used empirically to treat some infections or as prophylaxis. The characterization, definitive diagnosis, and susceptibility testing of oral bacterial infections are valuable in guiding appropriate therapy and in prevention of disease.

Capnocytophaga canimorsus: an emerging cause of sepsis, meningitis, and post-splenectomy infection after dog bites

Newly named in 1989, Capnocytophaga canimorsus is a bacterial pathogen found in the saliva of healthy dogs and cats, and is transmitted to humans principally by dog bites. This review compiled all laboratory-confirmed cases, animal sources, and virulence attributes to describe its epidemiology, clinical features, and pathogenesis. An estimated 484 patients with a median age of 55 years were reported, two-thirds of which were male. The case-fatality rate was about 26%. Its clinical presentations included severe sepsis and fatal septic shock, gangrene of the digits or extremities, high-grade bacteremia, meningitis, endocarditis, and eye infections. Predispositions were prior splenectomy in 59 patients and alcoholism in 58 patients. Dog bites before illness occurred in 60%; additionally, in 27%, there were scratches, licking, or other contact with dogs or cats. Patients with meningitis showed more advanced ages, higher male preponderance, lower mortality, and longer incubation periods after dog bites than patients with sepsis (p < 0.05). Patients with prior splenectomy presented more frequently with high-grade bacteremia than patients with intact spleens (p < 0.05). The organism possesses virulence attributes of catalase and sialidase production, gliding motility, cytotoxin production, and resistance to killing by serum complement due to its unique lipopolysaccharide. Penicillin is the drug of choice, but some practitioners prefer third-generation cephalosporins or beta-lactamase inhibitor combinations. C. canimorsus has emerged as a leading cause of sepsis, particularly post-splenectomy sepsis, and meningitis after dog bites.