Objective:To observe the susceptibility factors of elderly patients with corynebacterium striata in sputum of lower respiratory tract and analyze its clinical therapeutic effect.Methods:The clinical data of 192 elderly inpatients infected with corynebacterium striatum detected in sputum of lower respiratory tract were retrospectively analyzed in Quanzhou First Hospital Affiliated to Fujian Medical University from January 2019 to June 2021.The detection rate of corynebacterium striata was calculated, and the susceptibility factors and clinical efficacy were compared between the infection group(n=102)and the colonization group(n=90).Results:The detection rate of corynebacterium striata(detected cases / numbers of qualified lower respiratory tract sputum specimen)was 0.8%(72/8976)from January to December 2019, 2.3%(134/5877)from January to December 2020, and 3.0%(121/4 039)from January to June 2021, the difference was statistically significant( χ2=93.93, P<0.01). The detection rates of corynebacterium striatum during three corresponding periods in elderly patients were 0.6%(57/8 976), 1.4%(81/5 877)and 1.9%(78/4 039), respectively, with statistically significant differences( χ2=45.57, P<0.01). The incidences or values of following indexes were higher in infection group than in colonization group: age of patients, admission of intensive care unit, malnutrition, use of hormones, combined use of antibiotics, use of invasive mechanical ventilation, use of fiber bronchoscope, reduced cough reflex, other basic diseases, and so on, but the differences were not statistically significant(all P>0.05). The clinical effective rates were 41.2%(42/102)in the infection group and 48.9%(44/90)in the colonization group, respectively, and the differences was not statistically significant( P>0.05). Only 25 patients(24.5%)in the infected group were treated on corynebacterium striatum according to drug sensitivity results.Among them, the clinical effective rate of the treatment group and the untreated group was 68.0%(17/25)and 32.5%(25/77), respectively, the difference was statistically significant( χ2=9.84, P<0.01). The clinical effective rate of untreated group was lower than that of colonization group, the difference was statistically significant( χ2=4.62, P<0.05). Conclusions:The detection rate of corynebacterium striatum in elderly patients is high, and increases year by year.Patients infected with corynebacterium striatum usually has a variety of susceptibility factors, if not taking effective treatment measures, may have adverse outcomes.In clinical work, it is necessary to pay attention to and reduce the susceptibility factors of corynebacterium striatum, and to correctly interpret the etiological reports, so as to adopt a reasonable and effective therapeutic schedule.