Research from JAMA — Association of a Bundled Intervention With Surgical Site Infections Among Patients Undergoing Cardiac, Hip, or Knee Surgery

Object: Many studies that have evaluated surgical site infections (SSIs) after craniotomy or craniectomy (CRANI) did not use robust methods to assess risk factors for SSIs or outcomes associated with SSIs. The authors conducted the current study to identify risk factors for SSIs after CRANI procedures and to evaluate outcomes attributed to SSIs. Methods: The authors performed a nested case-control study of patients undergoing CRANI procedures between 2006 and 2010 at the University of Iowa Hospitals and Clinics. They identified 104 patients with SSIs and selected 312 controls. They collected data from medical records and used multivariate analyses to identify risk factors and outcomes associated with SSIs. Results: Thirty-two percent of SSIs were caused by Staphylococcus aureus, 88% were deep incisional or organ space infections, and 70% were identified after discharge. Preoperative length of stay (LOS) ≥ 1 day was the only significant patient-related factor in the preoperative model (OR 2.1 [95% CI 1.2–3.4]) and in the overall model (OR 1.9 [95% CI 1.1–3.3]). Procedure-related risk factors that were significant in the overall model included Gliadel wafer use (OR 6.7 [95% CI 2.5–18.2]) and postoperative CSF leak (OR 3.5 [95% CI 1.4–8.5]). The preoperative SSI risk index, including body mass index, previous brain operation, chemotherapy on admission, preoperative LOS, procedure reason, and preoperative glucose level, had better predictive efficacy (c-statistic = 0.664) than the National Healthcare Safety Network risk index (c-statistic = 0.547; p = 0.004). Surgical site infections were associated with increased LOS during the initial hospitalizations (average increase of 50%) or readmissions (average increase of 100%) and with an increased risk of readmissions (OR 7.7 [95% CI 4.0–14.9]), reoperations (OR 36 [95% CI 14.9–87]), and death (OR 3.4 [95% CI 1.5–7.4]). Conclusions: Surgeons were able to prospectively assess a patient's risk of SSI based on preoperative risk factors and they could modify some processes of care to lower the risk of SSI. Surgical site infections substantially worsened patients' outcomes. Preventing SSIs after CRANI could improve patient outcomes and decrease health care utilization.

Urinary tract infections (UTIs) are one of the most common pediatric infections. Our objective in this study is to investigate the association between urine pH and uropathogens in pediatric patients. The source population comprised 26 066 paired urinalysis (UA) and urine culture (UC) samples obtained from pediatric patients. We classified the paired UA-UC samples into UTI positive (N = 6348) and UTI negative (N = 19 718) according to the colony forming units corresponding to the sampling source. We included UTI positive patients with infection caused by a single species of pathogen (N = 5201) and frequency matched them with UTI negative patients (N = 4729) by age, sex, sampling source, and visit type. This study included 5201 pediatric patients with UTIs and found that urine with Proteus mirabilis or Pseudomonas aeruginosa demonstrated the least acidic pH (mean pH = 6.72 and 6.62, respectively), whereas urine with Escherichia coli or Klebsiella pneumoniae exhibited the most acidic pH (pH = 6.21 and 6.18). After stratifying the UTI samples by their pH range (<6, 6-6.9, 7-7.9, and ≥8). The prevalence of P. mirabilis increased significantly across increasing pH categories. This research is the first epidemiological study that linked urine pH to specific uropathogens in a pediatric population. Both urine pH and age are associated with certain causative uropathogens. Urine that grew P. mirabilis or P. aeruginosa had the least acidic pH. Additional studies should validate the role of urine pH in predicting uropathogens and UTI.

Object: The risk of surgical site infection (SSI) after craniotomies or craniectomies in patients in whom contaminated bone flaps have been reimplanted has not been determined. The objectives of this study were to identify the prevalence of bone flaps with positive cultures—especially those contaminated with Propionibacterium acnes—to assess the risk of SSI after reimplanting (either during the initial operation or subsequently) bone flaps with positive cultures, and to identify risk factors for SSI following the initial craniotomies or craniectomies. Methods: The authors conducted a retrospective review of cases in which patients underwent craniotomy/craniectomy procedures between January and October 2007 in the neurosurgery department at the University of Iowa Hospitals and Clinics. They also reviewed processes and procedures and did pulsed field gel electrophoresis of P. acnes isolates to look for a common source of contamination. They then conducted a prospective cohort study that included all patients who underwent craniotomy/craniectomy procedures between November 2007 and November 2008 and met the study criteria. For the cohort study, the authors obtained cultures from each patient's bone flap during the craniotomy/craniectomy procedures. Data about potential risk factors were collected by circulating nurses during the procedures or by a research assistant who reviewed medical records after the procedures. An infection preventionist independently identified SSIs through routine surveillance using the Centers for Disease Control and Prevention's definitions. Univariate and bivariate analyses were performed to determine the association between SSI and potential risk factors. Results: The retrospective review did not identify specific breaks in aseptic technique or a common source of P. acnes. Three hundred seventy-three patients underwent 393 craniotomy/craniectomy procedures during the cohort study period, of which 377 procedures met the study criteria. Fifty percent of the bone flaps were contaminated by microorganisms, primarily skin flora such as P. acnes, coagulase-negative staphylococci, and Staphylococcus aureus. Reimplanting bone flaps that had positive culture results did not increase the risk of infection after the initial craniotomy/craniectomy procedures and the subsequent cranioplasty procedures (p = 0.80). Allowing the skin antiseptic to dry before the procedures (p = 0.04, OR 0.26) was associated with lower risk of SSIs. Female sex (p = 0.02, OR = 3.49) was associated with an increased risk of SSIs; Gliadel wafer implants (p = 0.001, OR = 8.38) were associated with an increased risk of SSIs after procedures to treat tumors. Conclusions: Operative factors such as the way the skin is prepared before the incision rather than the skin flora contaminants on the bone flaps may play an important role in the pathogenesis of SSIs after craniotomy/craniectomy. Gliadel wafers significantly increased the risk of SSI after procedures to treat tumors.

Study Design. Matched case-control study. Objective. To identify modifiable risk factors for surgical site infections (SSIs) after pediatric spinal fusion. Summary of Background Data. The number of SSIs after pediatric spinal fusions increased. Methods. Between July 2001 and July 2010, 22 of 598 pediatric patients who underwent spinal fusion at a university hospital acquired SSIs. Each patient with an SSI was matched with 2 controls by procedure date. Bivariable and multivariable analyses were used to identify risk factors for SSIs and outcomes of SSIs. Results. Gram-negative organisms caused more than 50% of the SSIs. By multivariable analysis, neuromuscular scoliosis (odds ratio [OR] = 20.8; 95% confidence interval [CI], 3.1–889.5; P < 0.0001) and weight-for-age at the 95th percentile or higher (OR = 8.6; 95% CI, 1.2–124.9; P = 0.02) were preoperative factors associated with SSIs. Blood loss (OR = 1.0; 95% CI, 1.0–1.0; P = 0.039) and allografts and allografts in combination with other grafts were operative risk factors for SSIs. The final overall risk model for SSIs was weight-for-age at the 95th percentile or higher (OR = 4.0; 95% CI, 1.4–∞; P = 0.037), American Society of Anesthesiologists score 3 or more (OR = 3.8; 95% CI, 1.6–∞; P = 0.01), and prolonged operation duration (OR = 1.0/min increase; 95% CI, 1.0–1.0; P = 0.004). SSIs were associated with 2.8 days of additional postoperative length of stay (P = 0.02). Neuromuscular scoliosis was the only factor significantly associated with hospital readmission (OR = 23.6; 95% CI, 3.8–147.3; P = 0.0007). Conclusion. Our results suggest that pediatric patients undergoing spinal fusion might benefit from antimicrobial prophylaxis that covers gram-negative organisms. Surgical duration, graft implantation, and blood loss are potentially modifiable operative risk factors. Neuromuscular scoliosis, high weight-for-age, and American Society of Anesthesiologists scores 3 or more may help surgical teams identify patients at high risk for SSI. Level of Evidence: 4