The First Report of Extended-Spectrum β-Lactamase (ESBL) Genes in an Escherichia coli Isolate from a One-Month-Old Infant with Acute Lymphoblastic Leukemia (ALL) in Iran

Background: Bloodstream infection is one of the most life-threatening complications recognized as the frequent cause of treatment failure in children with acute lymphoblastic leukemia. Objectives: In this study, we describe the isolation of an extended-spectrum β -lactamase (ESBL)-producing Escherichia coli . Methods: Antimicrobial susceptibility tests were determined on the isolate by the Kirby-Bauer disk diffusion method. In addition, ESBLproductionof theisolatewasexaminedusingtheCombinationDiskDiffusionTest(CDDT).PCRwasusedtoscreenthepresence of CTX-M-1, CTX-M-2, CTX-M-8, CTX-M-9, CTX-M-25, ISEcp1, IS 2 6, and IS 903 genes in this isolate. Results: We found an ESBL-producing E. coli in a 1-month-old infant with a blood cancer that carried CTX-M-1 group enzymes. Conclusions: Our finding emphasized the need for more precise screening methods to identify the causative infectious agents at early stages of infection to choose the appropriate treatment in these severely immunocompromised patients. (GEN, 10 µ g), Lev-ofloxacin (LEV, 5 µ g) and susceptible to Imipenem (IPM, 10 µ g). The combination Disk Diffusion Test (CDDT) results revealed that the isolate was positive for producing extended- spectrum β -lactamase (ESBL). The isolate was positive for CTX-M-1 (CTX-M-15), ISE cp1 , IS 26 , and IS 903 elements and negative for other CTX-M subclasses.