목적: This study aims to analyze and compare the microbiology profile of infected branchial cleft cysts and deep neck infections. By characterizing the predominant bacterial pathogens in each condition, this study provides insights into the potential differences in pathophysiology and informs optimal antibiotic management strategies. 방법:A retrospective descriptive study was conducted at a single tertiary medical center on patients diagnosed and treated for infected branchial cleft cysts and deep neck infections between January 2017 and June 2024. A total of 78 patients with deep neck infections and 16 patients with infected branchial cleft cysts who had positive culture results were included. Demographic data, medical history, treatment methods, and microbiological profiles, including bacterial classification and antibiotic resistance patterns, were analyzed. 결과:Among the 16 cases of infected branchial cleft cysts, Klebsiella species infections were significantly more common compared to deep neck infections (31.3% vs. 10.3%; p = 0.042, OR = 0.25). Conversely, Streptococcus species infections were significantly less frequent in infected branchial cleft cysts than in deep neck infections (43.8% vs. 76.9%; p = 0.013, OR = 4.29). Staphylococcus species infection rates did not significantly differ between the two groups (18.8% vs. 9.0%). Regarding antibiotic resistance patterns, no Klebsiella species isolates from infected branchial cleft cysts exhibited antibiotic resistance. However, in deep neck infections, two Klebsiella species isolates from diabetic patients demonstrated resistance to fourth- generation cephalosporin, levofloxacin, and gentamicin. 결론:The microbiological profile of infected branchial cleft cysts differs somewhat from that of deep neck infections. In this study, infected branchial cleft cysts exhibited a higher prevalence of Klebsiella species and a relatively lower rate of Streptococcus species infections compared to deep neck infections. These findings contribute to a better understanding of the pathophysiology of these infections and may help guide more effective antibiotic selection and treatment strategies. Based on these results, empirical antibiotic treatment with ceftriaxone and metronidazole may be recommended for non-septic patients without a history of diabetes. However, for septic patients or those with diabetes, piperacillin-tazobactam or fourth-generation cephalosporins should be considered. Further research with larger sample sizes is recommended to validate these findings.