Kingella Species
- Kingella belongs to the family Neisseriaceae in the γ-subgroup of the
- Species:
- K. denitrificans
- K.oralis
- K. potus.
- K. kingae was formerly a member of the genus Moraxella.
- K. denitrificans was formerly called CDC group “TM-1.”
- Kingella oralis was recovered from human dental plaque of a patient with adult periodontitis.
- Kingella potus was isolated from the zookeeper’s wound. Three days earlier, he had sustained the bite of a kinkajou (Potus potus).
Clinical Significance of Kingella Species:
- K. kingae is being recognized as an important human pathogen though it’s part of the normal microbiota of the upper respiratory and genitourinary tracts.
- In pediatric patients, it has emerged as a significant pathogen.
- It has caused primarily bacteremia and skeletal infections in them.
- In infants after 6 months of age, K. kingae colonizes the upper respiratory tract.
- In between 6 months and 2 years of age, the rate of colonization increases 10% to 12%
- Then the colonization begins to decline after this time.
- In a study it was found, during the first 2 years of life, invasive K. kingae disease occurred most frequently in previously healthy children.
- Transmission can occur from child to child by the respiratory route.
- Organisms may get entrance into the bloodstream through breaches in the oropharyngeal mucosa.
- In children, it causes the bone and joint infections.
- These infections present as bacteremia, septic arthritis, osteomyelitis, discitis, tenosynovitis, and dactylitis.
- Systemic infections in infants presents:
- low-grade fevers
- viral upper respiratory tract infections
- frequently stomatitis are present
- In most cases, K. kingae septic arthritis is an acute infection.
- From these patients, blood cultures are usually negative.
- K. kingae septic arthritis is usually monoarthritic.
- It involves joints being the knee, hip, and ankle.
- K. kingae also causes osteomyelitis affecting the femur, other long bones, the tibia, ulna, radius, and calcaneus bones.
- K. kinage also causes spondylitis and intervertebral discitis.
- It also causes pediatric osteoarticular infections of the lower sternum and the junction between the manubrium and the xyphoid process.
- Invasive K. kingae causes the following infection in children:
- acute lymphocytic leukemia
- congenital heart disease.
- Rarely, bacteremia and endocarditis are caused by K. kingae.
- In the patients with heart disease such as rheumatic heart disease, cardiac malformations, or those with cardiac prostheses, K. kingae endocarditis occurs.
- In adults and school-age children, K. kingae endocarditis occurs.
- Complications of kingae endocarditis:
- Pericarditis
- paravalvular abscess
- pericardial abscess
- embolic phenomena
- mycotic aneurysms
- cerebral and pulmonary infarcts
- septic shock
- congestive heart failure.
- In women with systemic lupus erythematosis, K. kingae endocarditis with meningitis has been reported.
- In the immunocompetent adults, K. kingae bacteremia without endocarditis has been reported.
- It causes dental manipulations.
- Additional complications of bacteremia and bone infections include:
- Meningitis
- hematogenous orbital cellulitis
- Endophthalmitis
- soft tissue infection
- corneal abscess.
- The clinical presentation of K. kingae bacteremia may mimic systemic neisserial infections (i.e., meningococcemia or disseminated gonococcal infection).
- K. denitrificans has also been reported as a cause of septicemia and native/prosthetic valve endocarditis.
- K. denitrificans has also been isolated from:
- empyema fluid of a patient with bronchogenic carcinoma
- the bone marrow of a patient with AIDS
- the amniotic fluid of a patient with chorioamnionitis
- a corneal ulcer
Cultural Characteristics of Kingella species:
- Kingella species are Gram-negative bacilli or coccobacilli.
- They occur in pairs or short chains.
- They are oxidase-positive and catalase-negative.
- All species grow on chocolate and blood agar
- Do not grow on MacConkey agar or other enteric media.
- All Kingella are negative for:
- arginine dihydrolase
- lysine and ornithine decarboxylases
- urease
- esculin hydrolysis
- ONPG hydrolysis
Biochemical characteristics for the identification of Kingella species are:
| Test | K.kingae | K.denitrificans | K.oralis | K.potus |
| HEM SBA | β-haemolysis | No haemolysis | No haemolysis | No haemolysis |
| Oxidase | Positive | Positive | Positive | Positive |
| Catalase | negative | negative | negative | negative |
| NO3RED | negative | positive | negative | negative |
| NO2RED | positive | positive | negative | negative |
| Indole | negative | negative | negative | negative |
| Urease | negative | negative | negative | negative |
| Esculin | negative | negative | negative | negative |
| ONPG | negative | negative | negative | negative |
| DNase | negative | negative | negative | positive |
| Gas from Glucose | negative | negative | negative | negative |
| Acid produced from: | ||||
| Glucose | positive | positive | positive | positive |
| Maltose | positive | negative | negative | negative |
| Fructose | negative | negative | negative | negative |
| Sucrose | negative | negative | negative | negative |
| Lactose | negative | negative | negative | negative |
| Xylose | negative | negative | negative | negative |
| Mannitol | negative | negative | negative | negative |
| Mannose | negative | negative | negative | negative |
| Galactose | negative | negative | negative | NA |
| Trehalose | negative | negative | negative | NA |
| Raffinose | negative | negative | negative | NA |
| Sorbitol | negative | negative | negative | NA |
- NA means not available
- HEM SBA: Hemolysis on sheep blood agar
- NO3RED: reduction of nitrate to nitrite
- NO2RED: reduction of nitrite to nitrogen gas
- ODC: ornithine decarboxylase
- ONPG: o-nitrophenyl-β-D-galactopyranoside
- DNase: Deoxyribonuclease