Biochemical Identification and Antibiotics Resistance of Citrobacter freundii Isolated from Diarrheal Cases in Thi-Qar Province, Iraq

Abstract

Abstract
Citrobacter freundii is an opportunistic pathogen associated with gastrointestinal infections in children, particularly in
areas with limited healthcare and inadequate antimicrobial management. This study aimed to determine the prevalence,
resistance patterns, and colony traits of C. freundii in stool samples from children under two years old admitted to Al-
Husain Teaching Hospital in Thi-Qar Province, Iraq. A total of 100 stool samples were collected and cultured. Among
the Gram-negative isolates, C. freundii made up 3%. Antimicrobial susceptibility testing revealed complete resistance
(100%) to first- and second-generation cephalosporins (cefazolin and cefuroxime), as well as the third-generation
cephalosporin ceftriaxone. There was moderate resistance (60%) to amoxicillin-clavulanic acid. In contrast, all isolates
were fully susceptible to carbapenems, aminoglycosides, and fluoroquinolones. These results confirm that the VITEK 2
Compact system is a quick and accurate method for identifying C. freundii and determining its susceptibility to
antibiotics. Additionally, the high resistance to cephalosporins underscores the urgent need for regular monitoring of
antimicrobial resistance and for informed choices about antibiotic use in managing pediatric diarrhea caused by
multidrug-resistant C. freundii .