Background: The objective of this investigation was to find and characterize the N-acyl-homoserine lactones (AHLs) produced by different strains of Klebsiella pneumoniae that are resistant against antibiotic in UTIs. In this study, the luxI gene responsible for the formation of the homoserin lactone acyl compound was identified. Materials and Methods: K. pneumoniae identification by selective agar supplement HiCrome^TMagar A total of one hundred K. pneumoniae isolates were recovered, investigated for their antibiotic susceptibility, and screened for AHL production using the methods of Crose-Streak Assay, Soft Agar Assay, and Thin-Layer Chromatography (TLC) Assay. DNA extraction and genotyping Using a commercial purification technique (presto Minigenomic DNA extraction kit; Geneaid, Thailand), Primers for luxI gene (Macrogen, Korea) selection according to the supplier's recommendation. Results: Different short- and long-chain AHL molecules were found, according to the findings, C6-HSL, C8-HSL, and C10-HSL among 100 K. pneumoniae isolates recovered from UTI samples. The results of this study showed that the 59 K. pneumoniae isolates under study were producers of N-acyl homoserine. AHLs produce if below a threshold level (OD≥0.2). The result was positive N-acyl homoserine with a positive luxI gene in 33 (82.5%) of the bacterial isolates, while 7 (17.5%) were negative for both the N-acyl homoserine and LuxI genes. The result was highly significant differences at p-value ≤0.0001.

Keywords: K.  pneumoniae, N-acyl-homoserine lactones molecules, luxI gene, UTI