Virulence factors and antimicrobial resistance pattern of Citrobacter freundii isolated from healthy pet turtles and their environment

Abstract

Background: Zoonotic Citrobacter freundii infection can occur if pet turtle owners fail to hygienically handle the turtle or the turtle’s environment. Therefore, the virulence characteristics and resistance patterns of C freundii to commonly used antimicrobials should be understood. Methodology: Citrobacter freundii isolates were characterized by conventional pathogenicity tests, such as proteolysis, biofilm formation and hemolysis, PCR assays of virulence genes and antimicrobial disk diffusion tests. Results: Forty seven presumptive C freundiii solates obtained from 41 fecal and 18 environmental samples including water and soil samples were confirmed as C freundii by biochemical tests and 16S rRNA gene sequencing. Proteolysis and biofilm formation were shown in 17 and 6 isolates, respectively. No isolates showed hemolysis. The PCR assay for the presence of sit-ii or sit-ii related genes and via B genes were successful in 2 and 4 isolates, respectively. in the antimicrobial susceptibility test, most isolates were susceptible to all tested antibiotics except ampicillin, amoxicillin, cephalothin, cefoxitin and nalidixic acid. Non-susceptible isolates to penicillins (piperacillin and ticarcillin), fluoroquinolones (ciprofloxacin and norfloxacin), aminoglycosides (gentamicin) and other antibiotics (trimethoprim/sulfamethoxazole) were frequently observed among the isolates. A few isolates were resistant to imipenem, aztreonam, ceftriaxone and cefotaxime. Conclusion: in conclusion, it can be said that pet turtles are a potential public health risk due to the virulence and antimicrobial resistance of C freundii.