An adult case of urinary tract infection with Kingella kingae: a case report

INTRODUCTION: Kingella kingae, though part of the normal upper respiratory tract and genitourinary tract, is increasingly being recognized as an important human pathogen. During the past decade, it has emerged as a significant pathogen in the pediatric age group primarily causing bacteremia and osteoarticular infections. Adult infection usually occurs in individuals who are severely immunocompromised and most infections have taken the form of septicemia or septic arthritis. Bacteremia due to K. kingae has been reported as the immediate cause of death in patients with acquired immunodeficiency syndrome. CASE PRESENTATION: We present a microbiologically confirmed urinary tract infection with K. kingae in an immunocompetent 45-year-old adult woman with post-menopausal bleeding and with a history of clots. Her urine was subjected to culture and sensitivity tests. The isolated colonies were identified as K. kingae because of their typical culture characteristics such as long incubation period required for growth, beta-hemolysis, positive oxidase and negative catalase, urease indole, nitrate and citrate tests. Penicillin G disc test was positive. They were sensitive to all conventional antibiotics. CONCLUSION: K. kingae infection is a rare occurrence in immunocompetent adults. Very few cases of microbiologically confirmed infections have been reported so far. The isolation of K. kingae from urine sample has rarely been reported. K. kingae isolates are either missed or misinterpreted by clinical microbiologists. Therefore, K. kingae deserves recognition as a pathogen.