Prevalence and Antibiotic Resistance Pattern of Streptococcus genus and Other Pathogens Isolated from Throat Culture Samples of Patients in Fatemeh Al-Zahra Hospital of Sari, Iran

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. 

In this cross-sectional study, we used 117 pharyngeal swabs samples obtained from patients referred to Fatemeh Zahra Hospital of Sari, Iran, in 2018. 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, Gramchr('39')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-2018 guidelines. The results were analyzed using SPSS 16.0 software and descriptive statistical methods.

The frequency of Streptococcus pneumoniae and Streptococcus pyogenes was 13.7% and 9.4%, respectively. However, the highest frequency belonged to Pseudomonas aeruginosa (14.5%), and the lowest to Citrobacter spp. (0.9%).

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.