P-872. Clinical and Microbiological Trends in <i>Citrobacter</i> Bacteremia: A Study from South India

Abstract Background Citrobacter spp are anaerobic Gram-negative bacilli, accounting for approximately 0.8% of all Gram-negative infections. This study aims to elucidate the clinical manifestations and drug susceptibility in Citrobacter infections. Clinical features of patients with Citrobacter bacteremia and comparison between Citrobacter koseri and other Citrobacter spp Methods We conducted a retrospective analysis of Citrobacter spp. bacteremia cases from 2016 to 2022. We assessed clinical profile, species, antimicrobial susceptibility and 28-day outcome. Blood cultures were processed using the BacT/ALERT, Vitek 2 system was employed for bacterial identification and antimicrobial susceptibility testing and reported as per CLSI criteria. Isolates with intermediate susceptibility were classified as non-susceptible. Comparison of antibiotic susceptibility between C Koseri and other Citrobacter spp Results Over the 7 year study period, 25 cases of Citrobacter bacteremia were identified, 60% were males. The median age was 52.5 years (IQR: 46 – 75), with 2 pediatric cases. The annual incidence of Citrobacter bacteremia displayed an upward trend, from 12% in 2016 to 24% in 2022. C. koseri emerged as the predominant species (72%), followed by C. freundii (24%) and C. farmeri (4%). The majority of patients (72%) had diabetes, 16% had chronic liver disease, 12% had malignancy. Risk factors for Citrobacter bacteremia included the presence of an indwelling bladder catheter (76%) and a central venous catheter (44%). Urinary tract was the most frequent source (56%), followed by abdominal (20%) and soft tissue (8%); a newborn had meningitis with brain abscess. The mean for Pitt’s bacteremia score was 1.52±2.6. The mean Charlson’s co-morbidity index was 2.76±2.3. Clinical features for the entire cohort and comparative results between C Koseri and other Citrobacter spp (grouped as non-koseri) is depicted in figure 1. Ciprofloxacin susceptibility was higher among C koseri (94%) as compared to other spp (71%). Antibiotic susceptibility for ceftriaxone was almost similar between the 2 groups. Susceptibility rates for other antibiotics and comparison between C Koseri and other spp are shown in figure 2. All isolates were susceptible to ertapenem, imipenem and amikacin. The overall 28-day mortality rate was 12%. Conclusion We found C. koseri more commonly, urinary source as the most common source and device presence as a significant risk factor. Antibiotic susceptibility was better for C. koseri compared to others. Disclosures All Authors: No reported disclosures