ABSTRACT
Background: The genus Acinetobacter is a diverse group of Gram‑negative bacteria involve at least 33 species using the molecular methods. Although the genus Acinetobacter comprises a number of definite bacterial species, some of these species are of clinical importance. Therefore, it is of vital importance to use a method which is able to reliably and efficiently differentiate the numerous Acinetobacter species. Objectives: This study aims to identify Acinetobacter of clinical isolates from Assir region to the species level by 16S‑23S intergenic spacers internal transcribed spacer (ITS) of ribosomal ribonucleic acid (rRNA). Materials and Methods: Deoxyribonucleic acid extraction, polymerase chain reaction amplification of 16S‑23S intergenic spacer sequences (ITS) was performed using the bacterium‑specific universal primers. Results: Based on the 16S‑23S intergenic spacers (ITS) of rRNA sequences, all isolates tested were identified as Acinetobacter baumannii. The isolates shared a common ancestral lineage with the prototypes A. baumannii U60279 and U60280 with 99% sequence similarities. Conclusion: These findings confirmed 16S‑23S rRNA ITS for the identification of A. baumannii of different genotypes among patients.