Abstract: Objective To investigate the influencing factors of bacterial cutural negative after the first surgery of acute hematogenous osteomyelitis(AHO)caused by Staphylococcus aureus and to provide scientific basis for optimizing surgical strategies and reducing surgical frequency. Methods A retrospective analysis was conducted on a cohort of 82 children with Staphylococcus aureus AHO who were admitted to Childrens Hospital Affiliated to Shandong University between January 2020 and November 2024. All patients underwent a procedure known as “bone fenestration combined with negative pressure wound therapy”. The bacterial culture of the pus obtained after the initial surgical procedure revealed the presence of Staphylococcus aureus. Following one or more surgical procedures, the bacterial culture yielded a negative result. The subjects were divided into two groups based on the result of the initial surgical procedure: a negative group(n=56)and a control group(n=26). A comprehensive clinical data were collected for two groups of AHO patients. The data include the following: gender, age, the time of onset, the present or absence of recurrent fever before and after surgery, long or short bones,combined arthritis, the number of surgeries, the results of bacterial culture, inflammatory markers(complete blood count, C-reactive protein, erythrocyte sedimentation rate)at the time of admission and 5-7 days after surgery, and the present of chronic osteomyelitis and pathological fractures during the postoperative period. Univariate analysis and binary Logistic regression analysis were used to evaluate and determine independent risk factors for bacterial culture negativily following the initial AHO surgery. The receiver operating characteristic(ROC)curve and the area under the curve(AUC)were used to evaluate the predictive efficacy of each independent risk factor for bacterial culture negative after the initial AHO surgery. Results There were significant differences between the two groups of children in terms of the number of surgeries(P<0.001), MRSA(P<0.001), preoperative CRP(P=0.004), postoperative neutrophil count(P=0.044), postoperative CRP(P<0.001), postoperative recurrent fever(P=0.048), and chronic osteomyelitis during follow-up(P=0.002), all of which were statistically significant. Binary Logistic regression revealed that preoperative CRP(OR=0.986, 95%CI: 0.974-0.998, P=0.023), postoperative CRP(OR=0.946, 95%CI: 0.910-0.984, P=0.006), and MRSA(95%CI: 0.015-0.307, P<0.001)were the independent risk factors.The ROC curve showed that cut-off values of preoperative and postoperative CRP were 53.76 mg/L and 9.25 mg/L, respectively.The analysis of the ROC curve indicated that the AUC of preoperative CRP combined with postoperative CRP was 0.812(P<0.001), and the predictive value was found to be significantly higher than that of each individual variable. Conclusion The majority of bacterial culture negative children with AHO demonstrate significant clinical improvement following the initial surgical intervention, accompanied by a substantial decrease in inflammatory markers and a reduction in postoperative complications. Independent risk factors for a negative bacterial culture following the initial surgical treatment of AHO include preoperative CRP≥53.76 mg/L, postoperative CRP≥9.25 mg/L, and the presence of MRSA. For low-risk AHO patients with MSSA infections and postoperative CRP ≤9.25 mg/L without recurrent fever, a single surgery is recommended.

Key words: Osteomyelitis, Surgery, Children, Staphylococcus aureus, Bacterial culture