The relationship between genetic variations and susceptibility to infection provides insight into the pathogenesis of diseases caused by infections, illustrating host–pathogen interactions, informing preventive measures, and offering a novel therapeutic approach.

This cross-sectional study was conducted at Baghdad Medical City Hospital from April 2024 to October 2024 and involved 100 subjects referred to the laboratory for confirmatory diagnosis. Bacterial isolates were identified using routine phenotypic and biochemical tests. DNA was extracted from participants and used to genotype the rs231775 single-nucleotide polymorphism (SNP) using TaqMan® SNP Genotyping Assays; the serum levels of interleukin-7 (IL-7) were also determined for the studied groups.

A total of 32 patients were infected with Acinetobacter baumannii, and 68 were controls. No statistically significant difference was noted between the blood group and the infection status (p = 0.109). The results indicated a highly statistically significant association between genotype AA and the occurrence of disease (p = 0.003) and an extremely significant association between genotype GG and the occurrence of disease (p < 0.001), respectively. The results indicated that individuals with the AA genotype had lower odds (odds ratio (OR) = 0.217) of having the disease, as did those with the AG genotype (OR = 0.80). However, the presence of the GG genotype GG exhibited higher odds in patients compared to the controls (OR = 5.439). Serum levels of IL-7 differed significantly between patients and controls (p < 0.001) and between the three genotype groups in patients (p = 0.029).

Individuals with genotypes AA and AG are characterized by protective attributes against infection with Acinetobacter baumannii, while those having the genotype GG are more prone to infection with this bacterium. Furthermore, an association between specific genotypes and serum levels of IL-7 can hint at the possible role of genetic polymorphism in modulating immune response in relation to bacterial infection.