Kingella kingae Intrauterine Infection: An Unusual Cause of Chorioamnionitis and Miscarriage in a Patient with Undifferentiated Connective Tissue Disease

Abstract

<i>Kingella kingae</i> is a Gram-negative coccobacillus belonging to the <i>Neisseriaceae</i> family. In children less than 4 years old, <i>K. kingae</i> invasive infection can induce septic arthritis and osteomyelitis, and more rarely endocarditis, meningitis, ocular infections, and pneumonia. In adults, it may be a cause of endocarditis. To date, <i>K. kingae</i> acute chorioamnionitis (AC) leading to preterm rupture of membranes (PPROM) and miscarriage has never been reported. Herein, we describe a case of intrauterine fetal death (IUFD) at 22 weeks' gestation due to <i>K. kingae</i> infection occurred in a patient affected by undifferentiated connective tissue disease (UCTD) in lupus erythematosus systemic (LES) evolution with severe neutropenia. <i>K. kingae</i> was isolated in placental subamnionic swab and tissue cultures as well as fetal ear, nose, and pharyngeal swabs. Placental histological examination showed necrotizing AC and funisitis. In the fetus, neutrophils were observed within the alveoli and in the gastrointestinal lumen. Maternal medical treatment for UCTD was modified according to the <i>K. kingae</i> invasive infection. In the event of IUFD due to AC, microbiological cultures on placenta and fetal tissues should always be carried out in order to isolate the etiologic agent and target the correct medical treatment.