Isolation and Identification of Candida and Bacterial Species from the Blood of Immunocompromised Patients in Kirkuk, Iraq

Abstract

Bloodstream infections (BSIs) are a major cause of morbidity and mortality among immunocompromised patients, yet local data from Iraq combining hemodialysis and oncology populations remain scarce. This study aimed to isolate and identify Candida and bacterial species from the blood of immunocompromised patients in Kirkuk, Iraq, and to characterize their antimicrobial susceptibility profiles. A total of 350 blood samples were collected between November 2024 and December 2025 from 160 hemodialysis patients, 170 oncology patients, and 20 healthy controls, cultured in Brain Heart Infusion Broth, and subjected to phenotypic, biochemical, VITEK 2, and molecular (ITS/16S rRNA) identification. Of 330 patient samples, 200 (60.6%) yielded positive growth, comprising 124 bacterial (62.0%) and 76 fungal (38.0%) isolates. Gram-negative bacteria predominated (87.10%), led by Escherichia coli (26.85%), with an unusually high combined proportion of Proteus mirabilis and Morganella morganii (26.64%); Staphylococcus aureus was the leading Gram-positive isolate (10.48%). Among Candida isolates, C. albicans was most prevalent (39.47%), followed by an unusually elevated proportion of the intrinsically fluconazole-resistant C. krusei (38.16%). Imipenem (84.7% susceptibility) and amphotericin B/micafungin (85.5% each) were the most effective antibacterial and antifungal agents, respectively. Molecular confirmation by Sanger sequencing validated species identity, with representative isolates deposited in GenBank. These findings reveal a distinctive local microbial and resistance profile among immunocompromised patients in Kirkuk and underscore the need for continued epidemiological surveillance to guide empirical therapy.