To investigate the correlation between preoperative ASB and PJI after the initial artificial joint replacement by comparing the incidence of periprosthetic infection (PJI) between patients with preoperative asymptomatic bacteriuria (ASB) and patients without preoperative infection after primary arthroplasty, and to provide a basis for the treatment of preoperative ASB.

From January 2015 to December 2018, 1 294 patients with primary artificial joint replacement were analyzed in the Department of Orthopedics of the Second Affiliated Hospital of Xi′an Jiaotong University, and a total of 132 patients with a definitive diagnosis of ASB (prevalence of 10.2%) and 1 162 patients (89.8%) of non-ASB patients were confirmed. Exclusion criteria: patients with preoperative urinary tract infections, patients with previous urinary tract diseases, or other local infections. The ASB patients were divided into two groups, the treated group and the untreated group. The patients were followed up≥12 months after discharge, with postoperative PJI as the clinical outcome. Clinically characteristic factors (including age, sex, surgical site, presence of diabetes mellitus, obesity) and the presence or absence of ASB were included in the univariate analysis, and bacteriological cultures of periprosthetic secretions were compared with the results of urine cultures in patients with PJI.

The incidence of PJI in the ASB group was 4. 6% (6/132); while the incidence of PJI was 1.3% (15/1 162) in The non-ASB group. The results showed that the incidence of PJI in the ASB group was significantly higher than that in the non-ASB group (χ²=7.864, P=0.005). Univariate analysis showed that the proportion of PJI patients with ASB was higher (P<0.05). There was no significant difference between the patients with or without diabetes or obesity (all P>0.05). In the ASB patients, the incidence of postoperative PJI was 4.7% (3/64) in the treatment group and 4.4% (3/68) in the untreated group; there was no significant difference between the two groups (P=1). The preoperative urine culture of the patients with ASB was mostly Gram-negative bacilli, especially escherichia coli, while the etiology of PJI infection was mostly Gram-positive cocci. Microbes isolated in PJI did not match those in the preoperative urine cultures of all the ASB patients, and no other factor was significantly associated with Gram-negative infection.

The use of antibiotics before artificial joint replacement in ASB patients does not significantly reduce the incidence of postoperative PJI. Moreover, the bacteria cultured in the urine of infected patients may not be consistent with the bacteria cultured locally in the PJI wound, nor does it support a direct relationship between PJI and ASB. Preoperative antibiotic therapy for ASB in patients with ASB is not necessary.