Mohsen Nazari - Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran
Mohammad Taha Ebrahimi - Department of Microbiology, School of Medicine, Tehran University of Medical Sciences, Tehran, Iran
Niloofar Mobarezpour - PPD Tuberculin Department, Razi Vaccine & Serum Research Institute, Karaj, Iran
Amin Sepehr - Department of Bacteriology, Pasteur Institute of Iran, Tehran, Iran

Introduction: Tracheal tubes are among the primary means of infection transmission in hospitals. Therefore, identifying microbial agents transmitted via this route is necessary to control and prevent these infections. This study aimed to investigate the prevalence of pharyngeal-contaminating microorganisms and their antibiotic resistance pattern.  Methods: In this cross-sectional study, we used ۱۱۷ pharyngeal swabs samples obtained from patients referred to Fatemeh Zahra Hospital of Sari, Iran, in ۲۰۱۸. The Samples were obtained using the sterile cotton swab from the throat and then cultured in the sheep blood agar. The positive colonies for the alpha-hemolytic test were subcultured on the Mueller-Hinton agar for further assays, including the susceptibility to optochin, catalase test, Gram's polychromatic stain, microscopic examination, pyrrolidonyl aminopeptidase (PYR) test, sensitization to bacitracin, and latex agglutination assay. The antibiotic susceptibility assay was performed using the agar disk diffusion method according to CLSI-۲۰۱۸ guidelines. The results were analyzed using SPSS ۱۶.۰ software and descriptive statistical methods. Results: The frequency of Streptococcus pneumoniae and Streptococcus pyogenes was ۱۳.۷% and ۹.۴%, respectively. However, the highest frequency belonged to Pseudomonas aeruginosa (۱۴.۵%), and the lowest to Citrobacter spp. (۰.۹%). Conclusion: Our results indicated increased antibiotic resistance in streptococcal strains due to inappropriate prescriptions and antibiotic misuse. Therefore, recognizing and controlling the contributing factors and the rational use of antibiotics can be very important.

Antibiotic Resistance pattern, Tracheal Tube, Streptococcal species