BACKGROUND AND OBJECTIVE: Streptococcus agalactiae is the major factor for sepsis and meningitis in newborns and pneumonia and bacteremia in the elderly. Despite the importance of this pathogen, no accurate statistics are available regarding the prevalence of associated infections in adults. The purpose of this study was to analyse the efficacy of gbs1805 gene in the identification of isolates using laboratory and bioinformatic analyses and determine the prevalence of infections caused by Streptococcus agalactiae.

METHODS: In this cross-sectional study, 522 urine samples and genital swabs were collected from patients with suspected urinary tract infections and analyzed using culture and biochemical tests. The Streptococcus agalactiae isolates were examined for the presence of gbs1805 gene and antibiotic susceptibility was determined using Clinical and Laboratory Standards Institute (CLSI) guidelines.

FINDINGS: In this study, 54 isolates of Streptococcus agalactiae (10.3%) were obtained from the infections. All the isolates had preserved gbs1805 genes. The highest and lowest sensitivities were related to ceftriaxone (76%) and erythromycin antibiotics (33%).

CONCLUSION: Identification of preserved gbs1805 gene in clinical samples can determine infections caused by Streptococcus agalactiae. Due to the growing resistance of isolates to penicillin, alternative antibiotics should be used for the treatment of infections caused by these bacteria.