Sanger sequencing reveals <i>Pseudomonas aeruginosa</i> was the most common cross-contamination of gastrointestinal endoscopy

A common cause of nosocomial infections is Pseudomonas aeruginosa. Has become a significant pathogen over the last two decades, accounting for 10% to 20% of infections in many hospitals. It demonstrates an inherent resistance to numerous antibiotics. This study was aimed to utilized advanced molecular techniques to identified Pseudomonas spp. that caused cross-contamination of stomach biopsies specimens taken by gastrointestinal endoscopy and its resistance to some common used antibiotics. A total of sixty-one biopsy tissue samples were taken from patients suffering of gastrointestinal disorder at Al-Karama and Al-Zahraa Teaching Hospitals. Bacterial species were identified by traditional techniques (Gram stain and biochemical tests) and molecular techniques (16S rRNA PCR-based techniques and Sanger sequencing) methods. On average 54.1% showed bacterial growth, 56.0% of them was identified as Pseudomonas.spp (P.aeruginosa and P.nitroreducens). In this study, P.aeruginosa was identified as the most prevalent contaminant associated with gastrointestinal endoscopies. It known to cause opportunistic and severe co-infections in patients. As far as we are aware, this is the first report of its kind identified and studied P.nitroreducens as a contaminant in Iraqi patients. Antibiotic susceptibility test was done and isolates showed various resistance and sensitivity patterns (high antibiotic resistance to Azithromycin, Ceftriaxone, Erythromycin and Trimethoprim, and low antibiotic resistance to Amikacin, Gentamicin, Levofloxacin and Piperacillin-Tazobactam). This study highlights attention to the critical issue of contamination in gastrointestinal endoscopes due to inadequate sterilization. Molecular methods especially Sanger sequencing proved more accurate than traditional identification. To the best of our knowledge, this study reveals new bacterial species in hospitals in Iraq. Additionally, the isolated bacterial species demonstrated various patterns of resistance and sensitivity based on antibiotic susceptibility testing.