Abstract: 【Abstract】 Objective To investigate the current status of multidrug-resistant bacteria （MDRO） wound infections in patients with autoimmune bullous diseases （AIBDs）, and to analyze their risk factors. Methods A retrospective study was conducted, and inpatients with AIBDs accompanied by wound infections were collected from Hospital of Dermatology, Chinese Academy of Medical Sciences from January 2020 to December 2022. A descriptive analysis was carried out to analyze the basic characteristics of these patients and pathogenic characteristics of MDRO. Univariate and binary logistic regression models were used to analyze independent risk factors for MDRO infections in patients with AIBDs. Differences between the MDRO infection group and common bacterial infection group were analyzed by using t test, Mann-Whitney U test and chi-square test. Results Totally, 271 patients with AIBDs accompanied by wound infections were included, including 159 males （58.7%） and 112 females （41.3%）, and 142 patients （52.4%） were aged over 60 years. Most patients with AIBDs were diagnosed with pemphigus vulgaris （131 cases, 48.3%）, or bullous pemphigoid （99 cases, 36.5%）. Bacterial culture was positive in all the patients, and 74 （27.3%） were infected with MDRO; a total of 108 strains of MDRO were detected, with relatively high detection rates of Staphylococcus （82 strains, 75.9%） and Enterobacter （15 strains, 13.9%）. Significant differences were observed between the MDRO infection group and the common bacterial infection group in the duration of hospitalization, involved body surface area, proportions of patients self-modificating drug dosage, proportions of patients topically using antibiotic ointments, proportions of patients using immunosuppressants, duration of glucocorticoid use, maximum dose of glucocorticoids and the first albumin level at admission （all P < 0.05）, while there were no significant differences in the gender, age, proportions of patients at first hospitalization, types of AIBDs, duration of education, body mass index, disease duration, proportions of smoking patients, proportions of drinking patients, proportions of patients with comorbid chronic diseases, surgical history, prevalence of hypoalbuminemia, prevalence of mucosal involvement, proportions of patients receiving topical glucocorticoids, proportions of patients using biological agents, duration of antibiotic use, and the first total protein level at admission between the two groups （all P > 0.05）. Logistic regression analysis showed that the use of topical antibiotic ointments, use of immunosuppressants, maximum dose of glucocorticoids, and self-modification of drug dosage were independent risk factors for MDRO infections （all P < 0.05）. Conclusions The patients with AIBDs were prone to develop MDRO infections in wounds, and Staphylococcus infections were the most common. The use of topical antibiotic ointments, use of immunosuppressants, high dose of glucocorticoids, and self-modification of drug dosage may increase the risk of infections in patients with AIBDs.

Key words: Skin diseases, vesiculobullous, Autoimmune diseases, Bacterial infections, Risk factors, Pemphigus, Pemphigoid, bullous, Drug resistance, bacterial, Staphylococcus