Pathogen Distribution, Drug Resistance, and Postoperative High-Quality Nursing Intervention Effectiveness in Knee Osteoarthritis Patients After Knee Arthroplasty With Postoperative Infection.

Objective: To analyze the distribution and drug resistance of pathogens in patients with postoperative infection following knee arthroplasty (TKA) for knee osteoarthritis (KOA) and to explore the effectiveness of high-quality nursing interventions postoperatively. Methods: A retrospective analysis was conducted on clinical data from 87 KOA patients who underwent TKA and developed postoperative wound infections (infection group) at the first Affiliated Hospital of Harbin Medical University from July 2022 to September 2024. Another 87 patients without postoperative infection during the same period were selected as the control group. Deep wound exudate samples were collected from the infection group for pathogen culture, isolation, and identification. Drug susceptibility testing was performed using the K-B disk diffusion method. Additionally, venous blood samples were collected from both the infection and control groups one week after surgery, and serum levels of inflammatory markers [interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), procalcitonin (PCT)] were measured using enzyme-linked immunosorbent assay (ELISA). According to the type of nursing interventions received, the infection group was divided into the conventional care group (n=43, receiving standard orthopedic perioperative care) and the high-quality care group (n=44, receiving comprehensive high-quality care based on routine care). The pain levels [Visual Analog Scale (VAS) scores], knee joint function [Hospital for Special Surgery (HSS) knee scores], activities of daily living (modified Barthel index), and patient satisfaction [Newcastle Satisfaction with Nursing Service (NSNS) scale] were compared between the two groups. Results: Among the 87 KOA patients with postoperative infection after TKA, 83 patients had a single pathogen infection, and 4 patients had mixed infections with two pathogens, resulting in the cultivation and isolation of 91 pathogens. Of these, 63 (69.23%) were Gram-positive bacteria, primarily Staphylococcus aureus (29.67%) and Staphylococcus epidermidis (17.58%). There were 25 (27.47%) Gram-negative bacteria, primarily Escherichia coli (9.89%) and Pseudomonas aeruginosa (6.59%). Three (3.30%) fungal strains were isolated, all identified as Candida albicans. Gram-positive bacteria showed high resistance to penicillin, benzylpenicillin, ampicillin, erythromycin, clindamycin, ciprofloxacin, and gentamicin, but low resistance to gatifloxacin, and no resistance to vancomycin or teicoplanin. Gram-negative bacteria showed high resistance to ciprofloxacin, levofloxacin, gentamicin, and tobramycin, but low resistance to cefepime, imipenem, meropenem, gatifloxacin, and amikacin. The infection group had significantly higher serum levels of IL-6, TNF-α, and PCT compared to the control group (P<0.05). The VAS scores at 24 hours, 3 days, and 7 days postoperatively were significantly lower in the high-quality care group compared to the conventional care group (P<0.05). The HSS scores and modified Barthel index scores at 3 months postoperatively were higher than preoperative values in both groups, with a greater improvement observed in the high-quality care group (P<0.05). The satisfaction rate in the high-quality care group (93.18%) was significantly higher than in the conventional care group (74.42%) (P<0.05). Conclusion: The primary pathogens causing postoperative wound infections in KOA patients after TKA are Gram-positive bacteria, with Staphylococcus aureus and Staphylococcus epidermidis being predominant. Serum levels of inflammatory markers are significantly higher in infection patients compared to non-infection patients. High-quality nursing interventions can effectively alleviate postoperative pain, promote recovery of knee joint function, enhance activities of daily living, and improve patient satisfaction.