The comparative survey of phenotypic methods and the 16S rRNA gene sequencing method for detecting genus and species of non-fermented gram-negative bacteria isolated from blood samples in Isfahan, Iran

Introduction: This study compared phenotypic methods and the 16S rRNA gene sequencing method to identify the genus and species of non-fermenting gram-negative bacilli isolated from blood culture samples. Objectives: The aim of this study was to evaluate the effectiveness of using the 16S rRNA gene sequencing method in detecting the genus and species of non-fermented gram-negative bacteria isolated from blood samples. Materials and Methods: A cross-sectional study was conducted from April 2019 to April 2020, including all patients who required sterile culture at AL Zahra and Kashani hospitals. Specimens were cultured in BACTEC and subjected to standard phenotypic methods. Subsequently, 16S rRNA gene sequencing was performed to detect gram-negative non-fermenting Bacillus bacteria at the genus and species level. A comparative evaluation was then conducted. Results: The study identified 30 bacteria. The 16S rRNA gene sequencing method observed that 83.3% of the diagnoses were Acinetobacter baumannii, while the phenotypic approach identified 86.7% as Acinetobacter. Conclusion: The results indicate a significant difference between the phenotypic method and 16S rRNA sequencing in detecting non-fermenting gram-negative bacilli (NFGNB).