Capnocytophaga

Capnocytophaga genus belongs to the family Flavobacteriaceae.

There are >9 species of Capnocytophaga, which can be divided into two groups – resident of human mouth flora and dog/cat mouth flora. A recent review by Jolivet-Gougion reported that conditions like diabetes and chemotherapy may increase the amount of Capnocytophaga in mouth flora.

• Species found in the human oral cavity - C. gingivalis, C. granulosa, C. haemolytica, C. leadbetteri, C. ochracea and C. sputigena.

• Species found in dog/cat oral cavity - C. canimorsus, C. cynodegmi, C. canis, and C. stomatis

It has been reported that upto 74% of the healthy dogs may carry Capnocytophaga in their mouth cavity. [Deddy, 2015]

The disease reported to be caused by Capnocytphaga are -

• Bacteraemia

• Endocarditis, Pericarditis

• Keratitis, endophthalmitis, meningitis, intracranial abscess

• Chest infection, empyema, mediastinal abscess

• Iliopsoas abscess, peritonitis

• Osteomyelitis

• chorioamnionitis, neonatal sepsis. etc.

C canimorsus infection may result in septic shock with fever, disseminated purpura/purpura fulminans, acute renal failure, and confusion.

Capnocytophaga has a significant ability to evade the immune system, at least at the early stages of infection. These properties have been observed in various strains –

• failure to interact with toll-like receptor 4,

• prevent development of inflammatory responses and

• resistant to complement-mediated killing and phagocytosis by polymorphonuclear cells.

It is a

• Slow growing, capnophilic, facultative anaerobe.

• Grow on blood and chocolate agar but not MacConkey agar.

• Oxidase +ve, Catalase +ve, indole -ve, urease -ve,

• Identification confirmation – 16S rRNA, MALDI-ToF

• Capnocytophaga spp produces various types of beta-lactamases – TEM-17, CSP-1, CfxA, conferring resistance to penicillins, cephalosporins, aztreonam and monobactams.

• However, C canimorsus rarely produces beta-lactamase [Chesdachai, 2021]

• Betalactam-betalactamse combinations (pip-tazobactam, coamoxiclav), and carbapenems are active.

Capnocytophaga ochracea

Commonest Capnocytophaga species to cause bactaeraemia in the auto-HSCT and neutropenic patients. [Ramírez Isabel 2019, Liu 2021]

Capnocytophaga sputigena

C. sputigena has been involved in abscesses, bactearemia, chorioamnionitis, empyema, endocarditis, osteomyelitis, pleuropneumonitis, sinusitis, and septic abortion.

It is one of the 3 species that causes periodontitis - C. ochracea, C. gingivalis, and C. sputigena.