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Objective:To investigate the etiological characteristics and drug resistance patterns of multidrug-resistant organism (MDRO) infection in patients after cardiac surgery, so as to help clinicians rationally prescribe antimicrobials recommended by guidelines, increase the success rate of empirical antibacterial therapy and improve the prognosis of inpatients.Methods:Clinical data of 409 patients diagnosed with nosocomial infection (NI) after cardiac surgery from January 2018 to October 2021 were retrospectively collected. According to the results of culture, these cases were divided into two groups: MDR bacterial infection group (MDR, n=176) and non-MDR bacterial infection group (non-MDR, n=233). The etiological characteristics of MDRO infection and the patterns of drug resistance to commonly used clinical antibiotics were analyzed. Meanwhile, the etiological distribution, drug resistance and clinical outcome corresponding to different surgical types and clinical infection types were statistically analyzed. Results:A total of 306 strains of MDR bacteria were detected. Among the 176 patients, 97 (55.1%) were infected with more than one kind of MDRO and the mix infections were mainly caused by Klebsiella pneumoniae, Acinetobacter baumannii and/or Pseudomonas aeruginosa. Carbapenem-resistant (CR) bacteria accounted for 69.6% (213/306). Regardless of surgical type and clinical infection type, Acinetobacter baumannii (114/306, 37.3%) was the most common pathogenic bacteria, followed by Klebsiella pneumoniae (72/306, 23.5%) and Pseudomonas aeruginosa (55/306, 18.0%). Most of the clinical specimens were sputum specimens (528/601, 87.9%) and most of the isolated strains were carbapenem resistant, MDR and extensively drug-resistant (XDR). The positive rates of MDR bacteria were 53.7% and 53.1% in patients undergoing coronary artery bypass grafting (CABG) and aortic surgery, respectively, while the positive rates of pandrug-resistant bacteria were relatively low. In vitro drug sensitivity test results showed that MDR bacteria were highly resistant to levofloxacin (64.4%) and cefepime (61.4%), and then to ciprofloxacin (54.6%), ceftazidime (53.9%) and cotrimoxazole (52.4%). However, the resistance rates to polycolistin (5.5%) and amikacin (7.2%) were low. Compared with non-MDR bacteria, MDR bacteria were less susceptible to ceftazidime (χ 2=156.663, P<0.001), ceftriaxone (χ 2=27.844, P<0.001), cefepime (χ 2=210.181, P<0.001), imipenem (χ 2=173.242, P<0.001), levofloxacin (χ 2=201.521, P<0.001), ciprofloxacin (χ 2=180.187, P<0.001), amikacin (χ 2=16.661, P<0.001), gentamicin (χ 2=46.047, P<0.001), tobramycin (χ 2=106.546, P<0.001), piperacillin (χ 2=7.325, P=0.007), ampicillin/sulbactam (χ 2=5.415, P=0.020), piperacillin/tazobactam (χ 2=139.506, P<0.001), cefoperazone/sulbactam (χ 2=102.832, P<0.001), cotrimoxazole (χ 2=121.217, P<0.001), aztreonam (χ 2=6.977, P=0.008) and minocycline (χ 2=53.107, P<0.001). Although there was no significant difference in the detection rates of pathogenic bacteria between patients undergoing different types of surgery or having different types of infection, the mortality rate of NI after cardiac surgery, especially MDR bacterial infection, was as high as 30.0%. Moreover, the mortality rate was closely related to the types of clinical infection. The all-cause mortality of common pulmonary infection and bloodstream infection (BSI) was 10.0% to 20.0%, and once the patient′s condition was not under control and progressed to severe infection or even septic shock, the all-cause mortality would double. Conclusions:MDR bacterial infections would bring great challenges to patients after cardiac surgery, especially gram-negative bacteria (GNB) such as Klebsiella pneumoniae, Acinetobacter baumannii and Pseudomonas aeruginosa. More than half of the patients would have mixed infections caused by carbapenem resistant, XDR or even pandrug-resistant bacteria, resulting in limited choice of anti-infective drugs and poor prognosis in hospitalized patients.
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Objective:To evaluate the perioperative and follow-up data of carotid artery stenting (CAS)+ coronary artery bypass grafting (CABG) and CABG alone, and to assess the safety and efficacy of CAS in the treatment of severe stenosis of the carotid artery in combination with asymptomatic carotid artery stenosis.Methods:A retrospective analysis of 700 CABG patients combined asymptomatic carotid artery severe stenosis at Beijing Anzhen Hospital, Beijing Chaoyang Hospital, and Beijing Tiantan Hospital from January 2018 to December 2022 was performed. According to whether or not underwent CAS treatment, they were divided into the CAS-CABG group(116 cases)and the CABG-only group(584 cases). The mean age of the CAS-CABG group was (64.8±7.3) years, and all of them underwent unilateral CAS surgery only; the mean age of the CABG only group was (65.5±7.6) years. The main results of the patients in the two groups were compared at 30 days after the operation and follow-up period.Results:The early postoperative stroke rate was significantly lower in the CAS-CABG group(2.6% vs. 9.1%, P=0.02), while the combined procedure did not increase the rates of mortality and adverse events during follow-up. Subgroup analysis revealed that there was no significant difference in stroke rates between the two procedures for asymptomatic unilateral carotid artery stenosis, advanced age, history of atrial fibrillation, and history of stroke were independent risk factors for early stroke in CABG for asymptomatic unilateral carotid artery stenosis. Conclusion:CAS-CABG is safe and effective in the treatment of coronary artery disease combined with asymptomatic carotid artery stenosis, and can reduce the incidence of early postoperative stroke in patients. CABG patients with asymptomatic carotid stenosis should be rationally screened for prophylactic CAS to reduce the risk of postoperative stroke in these patients.