BackgroundWe sometimes experience postoperative surgical site infection (SSI) at the chest tube drainage site (CDS) after thoracotomy. The incidence of and risk factors for SSI at the CDS have remained unclear.MethodsWe conducted a prospective study to determine the incidence and risk factors for SSI at the CDS. We analyzed 99 patients who underwent lobectomy or segmentectomy for pulmonary malignant lesions.ResultsThere were 56 males and 43 females with an average age of 71 years. The postoperative drainage period was 2–15 days. Bacterial species were detected in secretions in 18 of 99 cases (18.2%). Older age was a risk factor for the detection of bacteria at the timing of chest tube removal. Eighteen cases (18.2%) were diagnosed with presence of SSI at the CDS at the timing of staple or suture removal. A pathological diagnosis of squamous cell carcinoma was regarded as a candidate risk factor for SSI. Eleven of 18 SSI patients showed delayed wound healing. A higher level of HbA1c was found in patients with delayed wound healing. Enterococcus faecalis infection may influence the development of complex SSI.ConclusionsWe identified the bacterial profiles, incidence of and risk factors for SSI at the CDS. More intense preoperative glycemic control and an understanding of the bacterial profile and may be useful for reducing the incidence of SSI chest tube drainage sites (CDS).