Molecular and Biochemical identification of gram-negative bacteria associated with gastrointestinal endoscopy

Abstract

Gastrointestinal diseases affect millions of individuals globally each year, ranking among the most significant health concerns worldwide. These conditions severely diminish quality of life and impose substantial economic burdens on healthcare systems. A major contributing factor to the development of infections linked to healthcare is the cross-contamination of gastrointestinal endoscopes, which frequently occurs as a result of insufficient sterilization practices. This study identifies the bacterial species present, assesses their antibiotic resistance and susceptibility profiles, and investigates into the level of microbial contamination in endoscopes used in Al-Zahraa and Al-Karama teaching hospitals.

A total of 61 gastric biopsy samples were obtained from patients aged 17 to 75 years suffering from gastrointestinal disorders during a six-month study period. These samples were processed using conventional biochemical methods for initial culturing and identification. Molecular techniques, including 16S rRNA gene amplification and Sanger sequencing, were employed for precise bacterial identification. The Kirby-Bauer disk diffusion method was utilized to determine the responsiveness of bacterial isolates to eight antibiotics from six different classes.         

Bacterial growth was observed in 54.09% (33/61) of the collected samples. Molecular analysis identified six distinct bacterial species, including Achromobacter anxifer, Pseudomonas nitroreducens, Shigella flexneri, and Stenotrophomonas maltophilia, which were reported for the first time in Iraqi patients. Additionally, common pathogens such as Klebsiella pneumoniae and Pseudomonas aeruginosa were also identified. Antibiotic susceptibility testing revealed that amikacin, gentamicin, levofloxacin, and piperacillin-tazobactam exhibited high efficacy, whereas azithromycin, erythromycin, ceftriaxone, and trimethoprim showed significant resistance among the isolates.

This study emphasizes the pressing issue of microbial contamination in gastrointestinal endoscopes, highlighting the necessity for stringent sterilization practices and routine microbiological monitoring. The results underline the critical role of tailored antibiotic treatments and enhanced infection control strategies to reduce cross-contamination, improve patient safety, and address the growing challenge of antimicrobial resistance in healthcare settings.