To investigate the characteristics of pathogenic bacteria and related factors of nosocomial infection in the maxillofacial surgery inpatients.

A total of 15 876 patients with oral and maxillofacial surgery admitted to Hospital of Stomatology of Sun Yat-sen University from 2014 to 2019 were selected as the research subjects. SPSS 26.0 software was used for data analysis. The incidence of nosocomial infections in the patients was assessed. The strains of the infected patients were isolated and identified through bacterial culture. The characteristics of the pathogens were analyzed through drug susceptibility tests. The influencing factors of nosocomial infection was analyzed through single factor (χ² test) and multiple factors (Logistic regression model) .

There were 188 cases of nosocomial infection out of 15 876 total cases included in this study. The infection rate was 1.18% and the two main infection sites were the surgical site and lower respiratory tract. 249 samples from nosocomial infection cases were co-cultured for pathogenic result and bacteria groups were isolated, out of which there were 182 gram-negative bacteria samples (accounting for 73.10%, mainly Pseudomonas aeruginosa) , 64 samples showed of gram-positive bacteria (taking up for 25.70%, mainly Staphylococcus aureus) , 3 fungi results (accounting for 1.20%) . Isolated Pseudomonas aeruginosa showed high resistance rate to imipenem, but is more sensitive to other antibacterial drugs such as levofloxacin. Isolated Klebsiella pneumoniae has a high resistance rate to ampicillin but is more likely to be controlled by ceftazidime. The isolated Staphylococcus aureus showed relatively higher resistant chance to penicillin but was more sensitive to linezolid. The results of univariate analysis showed that age, gender, tracheotomy, free flap surgery and malignant tumors were the influencing factors of nosocomial infection in patients of oral and maxillofacial surgery (P<0.05) . The results of multivariate logistic regression analysis showed that, factors of age, tracheotomy and malignant tumors are considered related to infection (P<0.05) .

Gram-negative bacteria is the main bacterial group that causes infection. Several factors are considered to be counting for the infection and may have interacting effect. Clinical interventions should be made to prevent or reduce infection cases. According to the characteristics of pathogenic bacteria, it provides the basis for rational use of antibiotics in clinical practice, so as to improve the quality of anti-infection treatment.