Isolation and identification of some predominant bacteria and assessment of TNF-α level in serum of patients with gingivitis

Abstract

This study was conducted to diagnose the aerobic bacterial species causing gingivitis, reveal the antibiotic susceptibility pattern and assess the level of tumor necrosis factor-alpha (TNF-α) in serum of patients with gingivitis. In total, 110 samples (including patient group and control group) were collected during the period from November 2021 until March 2022. Of which, 80 samples were collected by using oral swabs from patients attending the College of Dentistry at Tikrit University and outpatient clinics of both gender with different age groups. While the remaining 30 samples were collected from healthy individuals representing the control group. Identification of bacterial isolates was performed depending on micro and macroscopic cultural characteristics and biochemical tests. In addition to assessing the biochemical characteristics of the isolates, a VITKE2 compact system was used to ensure the identification of species level. The TNF-α concentrations in the serum were determined using an enzyme-linked immunosorbent assay known as a sandwich ELISA. Out of 80 samples, 60 (75%) samples showed positive bacterial growth cultures, while 20 (25%) samples showed no bacterial growth. The most common isolated bacteria species was Streptococcus mutans (18%), followed by Streptococcus mitis (13%), Staphylococcus aureus (12%) Streptococcus salivarius, Streptococcus pyogenes (8%) Staphylococcus  epidermidis, Enterococcus feacalis, Escherichia coli, Klebsilla pneumoniae (6%), Rothia dentocariosa, Pseudomonas aeruginosa (4%), and Streptococcus pneumonia, Kocuria kristinae, Granulicatella adiacens (3%). The sensitivity of the bacterial isolates under study was tested to 11 antibiotics. Different species of bacteria showed various sensitivity patterns to several kinds of antibiotics. The study recorded a high significant difference (P=0.0007) between the patients (56.54 + 9.32 pg/ml) and the control group (31.88 + 7.44 pg/ml) concerning the level of TNF-α. In conclusion, the predominant bacteria identified from gingivitis patients were S. mutans and S. mitis. In addition, the levels of TNF-α in gingivitis patients were significantly higher than in the control group.