Hamadan University of Medical Sciences Avicenna Journal of Clinical Microbiology and Infection 2383-0298 13 1 2026 02 23 Bioinformatics Analysis of Genetic Variations and Clonal Relationships of Clinical Enterococci Species in the Context of Antibiotic Resistance in Iraq 18 27 10.34172/ajcmi.3721 EN Raid Razzaq Ojaimi https://orcid.org/0000-0002-3633-0015 Journal Article 10.34172/ajcmi.3721 2025 07 03 2025 08 16 Background: Antibiotic-resistant enterococci have turned into major pathogens in humans in Iraq. Therefore, this study examined genetic variations and clonal relationships among Enterococcus strains concerning antibiotic resistance in Al-Diwaniya, Iraq, using RAPD-PCR. Methods: Overall, 250 clinical samples were collected under sterilized conditions between December 2020 and May 2021. Using standard methods, enterococci isolates were identified and evaluated for antibacterial susceptibility. Moreover, molecular techniques were utilized to examine genetic variations and clonal relationships of Enterococcus spp. and detect EsβL genes. The random amplified polymorphic deoxyribonucleic acid-polymerase chain reaction (RAPD-PCR) results were analyzed by BioNumerics software. Results: Thirty-four enterococci strains were isolated and identified by amplifying and sequencing the 16S–23S rRNA gene. Of these strains, 82.3%, 8.8%, 5.8%, and 2.9% were identified as E. faecalis, E. faecium, E. casseliflavus, and E. gallinarum, respectively. The highest antibiotic resistance among E. faecium isolates was associated with ampicillin, cefotaxime, ceftriaxone, and gentamicin (100%), while the lowest resistance belonged to chloramphenicol (66.60%). Multidrug-resistant and extensively drug-resistant strains were present in 50% and 5.8% of the enterococci isolates, respectively. The presence of the bla-TEM, bla-SHV, and bla-CTX-M2 genes in several isolates at frequencies of 44.1%, 38.2%, and 11.7%, respectively, indicated the spread of antibiotic resistance mechanisms. RAPD results confirmed a relationship between RAPD patterns, isolate sources, and antibiotic resistance patterns. Conclusion: Our findings demonstrated a distinct genotypic variety of the E. faecalis, E. faecium, E. casseliflavus, and E. gallinarum strains isolated from various clinical cases. RAPD analysis proved to be highly effective in determining the genetic variation among Enterococcus species.