An unusual case of Streptococcus cristatus infection in a patient with decompensated liver disease

Background: Cases of infections caused by Streptococcus cristatus, a member of the Mitis group within the Streptococcus genus and an important component of the oral microbiota, are quite rare. This study presents the first documented case of S. cristatus found in the ascitic fluid of a patient with decompensated liver disease. Methods: Ascitic fluid samples collected aseptically were inoculated into Brain Heart Infusion (BHI) broth (HiMedia, Mumbai, India) and incubated overnight at 35°C-37°C under optimal atmospheric conditions. After overnight incubation, the broth sample was then cultured on 5% sheep blood agar (HiMedia, Mumbai, India) and MacConkey agar plates (HiMedia, Mumbai, India) and incubated at 37°C for 18-24 hours. Results: Gram staining of the ascitic fluid sample revealed a few gram-positive cocci in pairs and chains. Significant growth of alpha-hemolytic colonies was observed and identified as Streptococcus cristatus using automated bacterial identification systems. Conclusion: Antimicrobial treatment was not initiated because the patient's family chose to forgo further clinical management. Effective treatment generally requires accurate identification of the bacterial isolate, appropriate and careful use of antibiotics, and patient education on the importance of oral hygiene.