Preoperative oral antibiotic prophylaxis reduces Pseudomonas aeruginosa surgical site infections after elective colorectal surgery: a multicenter prospective cohort study.

BACKGROUND: Healthcare-associated infections caused by Pseudomonas aeruginosa are associated with poor outcomes. However, the role of P. aeruginosa in surgical site infections after colorectal surgery has not been evaluated. The aim of this study was to determine the predictive factors and outcomes of surgical site infections caused by P. aeruginosa after colorectal surgery, with special emphasis on the role of preoperative oral antibiotic prophylaxis. METHODS: We conducted an observational, multicenter, prospective cohort study of all patients undergoing elective colorectal surgery at 10 Spanish hospitals (2011-2014). A logistic regression model was used to identify predictive factors for P. aeruginosa surgical site infections. RESULTS: Out of 3701 patients, 669 (18.1%) developed surgical site infections, and 62 (9.3%) of these were due to P. aeruginosa. The following factors were found to differentiate between P. aeruginosa surgical site infections and those caused by other microorganisms: American Society of Anesthesiologists' score III-IV (67.7% vs 45.5%, p = 0.001, odds ratio (OR) 2.5, 95% confidence interval (95% CI) 1.44-4.39), National Nosocomial Infections Surveillance risk index 1-2 (74.2% vs 44.2%, p < 0.001, OR 3.6, 95% CI 2.01-6.56), duration of surgery ≥75thpercentile (61.3% vs 41.4%, p = 0.003, OR 2.2, 95% CI 1.31-3.83) and oral antibiotic prophylaxis (17.7% vs 33.6%, p = 0.01, OR 0.4, 95% CI 0.21-0.83). Patients with P. aeruginosa surgical site infections were administered antibiotic treatment for a longer duration (median 17 days [interquartile range (IQR) 10-24] vs 13d [IQR 8-20], p = 0.015, OR 1.1, 95% CI 1.00-1.12), had a higher treatment failure rate (30.6% vs 20.8%, p = 0.07, OR 1.7, 95% CI 0.96-2.99), and longer hospitalization (median 22 days [IQR 15-42] vs 19d [IQR 12-28], p = 0.02, OR 1.1, 95% CI 1.00-1.17) than those with surgical site infections due to other microorganisms. Independent predictive factors associated with P. aeruginosa surgical site infections were the National Nosocomial Infections Surveillance risk index 1-2 (OR 2.3, 95% CI 1.03-5.40) and the use of oral antibiotic prophylaxis (OR 0.4, 95% CI 0.23-0.90). CONCLUSIONS: We observed that surgical site infections due to P. aeruginosa are associated with a higher National Nosocomial Infections Surveillance risk index, poor outcomes, and lack of preoperative oral antibiotic prophylaxis. These findings can aid in establishing specific preventive measures and appropriate empirical antibiotic treatment.

Increasing isolation of rapidly growing mycobacteria in a low-incidence setting of environmental mycobacteria, 1994-2015.

To determine trends in incidence and clinical relevance of rapidly growing mycobacteria (RGM) in a low-prevalence region of non-tuberculous mycobacteria. We retrospectively identified all patients with RGM-positive cultures between January 1994 and December 2015. Trends in incidence, clinical significance, and outcomes were assessed. One hundred and forty patients had RGM-positive cultures (116 respiratory and 24 extra-respiratory sources). The incidence of RGM isolates increased steadily from 2003 (0.34 per 100,000) to 2015 (1.73 per 100,000), with an average annual increase of 8.3%. Thirty-two patients (22.9%) had clinical disease, which trended to cluster in the second half of the study period. A positive acid-fast bacilli smear (odds ratio [OR] 97.7, 95 % CI 13.8-689.4), the presence of extra-respiratory isolates (OR 19.4, 95 % CI 5.2-72.7), and female gender (OR 5.9, 95 % CI 1.9-19.1) were independently associated with clinical disease. Cure rates were 73.3 and 87.5% for pulmonary and extra-pulmonary disease respectively. Although the burden of disease remains low, the presence of RGM isolates is increasing in our geographical setting. Whether this rise will be sustained over time and will coincide with an increase in clinical disease, or whether it is merely a cycle in the poorly understood epidemiological behaviour of environmental mycobacteria, will be seen in the near future.

The Impact of Culturing the Organ Preservation Fluid on Solid Organ Transplantation: A Prospective Multicenter Cohort Study.

BACKGROUND: We analyzed the prevalence, etiology, and risk factors of culture-positive preservation fluid and their impact on the management of solid organ transplant recipients. METHODS: From July 2015 to March 2017, 622 episodes of adult solid organ transplants at 7 university hospitals in Spain were prospectively included in the study. RESULTS: The prevalence of culture-positive preservation fluid was 62.5% (389/622). Nevertheless, in only 25.2% (98/389) of the cases were the isolates considered "high risk" for pathogenicity. After applying a multivariate regression analysis, advanced donor age was the main associated factor for having culture-positive preservation fluid for high-risk microorganisms. Preemptive antibiotic therapy was given to 19.8% (77/389) of the cases. The incidence rate of preservation fluid-related infection was 1.3% (5 recipients); none of these patients had received preemptive therapy. Solid organ transplant (SOT) recipients with high-risk culture-positive preservation fluid receiving preemptive antibiotic therapy presented both a lower cumulative incidence of infection and a lower rate of acute rejection and graft loss compared with those who did not have high-risk culture-positive preservation fluid. After adjusting for age, sex, type of transplant, and prior graft rejection, preemptive antibiotic therapy remained a significant protective factor for 90-day infection. CONCLUSIONS: The routine culture of preservation fluid may be considered a tool that provides information about the contamination of the transplanted organ. Preemptive therapy for SOT recipients with high-risk culture-positive preservation fluid may be useful to avoid preservation fluid-related infections and improve the outcomes of infection, graft loss, and graft rejection in transplant patients.