Assessment of Silver Levels in a Closed-Incision Negative Pressure Therapy Dressing: In Vitro and In Vivo Study.

Objective: In recent years, reticulated open-cell foam-based closed-incision negative pressure therapy (ROCF-ciNPT) has shown effectiveness in management of various postoperative incisions. These dressings consist of a skin interface layer that absorbs fluid from the skin surface and reduces the potential for microbial colonization within the dressing by means of ionic silver. This study examines the ability of silver to reduce the bioburden within the dressing as well as the localized effect due to potential silver mobility. Approach: Ability of silver to reduce bioburden within the ROCF-ciNPT dressing was assessed using Staphylococcus aureus, Pseudomonas aeruginosa, and Candida spp. Furthermore, silver mobility was assessed using an in vitro skin model to study the zone of inhibition along with released silver quantification. Using a porcine model, diffusion of silver into blood and tissue was studied using emission spectrometry and histology. Results: Microbial growth in the ROCF-ciNPT dressing was significantly reduced (∼2.7-4.9 log reduction) compared to a silver-free negative control. No zone of inhibition was observed for microbial colonies for up to 7 days with minimal localized silver release (<5.5 ppm release). In vivo studies demonstrated no measurable concentration (<0.2 µg/g) of silver in the blood, urine, feces, kidney, and liver tissue biopsy. Innovation: This study provides an important insight into silver concentration and mobility within the ROCF-ciNPT dressing, given emerging concerns associated with potential silver cytotoxicity. Conclusion: These results indicate the concentration of silver (0.019% silver by weight) in the ROCF-ciNPT dressings has been adequate to reduce bioburden within the skin interface layer, while severely limiting the amount of silver leaching out.

A systematic review of the clinical significance of nephrostomy urine cultures.

PURPOSE: There are few published reviews that have assessed the clinical utility of renal urine cultures following percutaneous nephrostomy (PCN). In this systematic review, we evaluated the published evidence of the clinical utility of nephrostomy urine cultures in the light of emerging antimicrobial resistance and need for stewardship. METHODS: We performed a systematic literature search and review for evidence on the utility and role of nephrostomy urine cultures, using Medline, Embase and PubMed. We looked for evidence to assess whether there is any utility in collecting renal urine for culture at the time of percutaneous nephrostomy (PCN) and if the culture results of nephrostomy urine and bladder urine are different. We studied outcomes of treatment based on nephrostomy culture results. We also examined the role of PCN cultures at the time of routine nephrostomy exchange. Finally, we assessed if doing a PCN leads to infection or pyelonephritis. RESULTS: From 94 studies initially identified, we finally selected two randomised clinical trials (RCT), six original articles and five detailed conference abstracts for the review. These studies suggest that PCN urine cultures are overall useful in clinical practice. They are useful in selecting appropriate antimicrobial treatment for urosepsis following upper urinary obstruction. There does not appear to be any advantage in performing PCN cultures at routine nephrostomy exchanges. Occasionally, PCN itself can lead to subsequent urosepsis. CONCLUSION: Nephrostomy urine cultures have utility in clinical practice and can help support treatment and antimicrobial stewardship.

Complications of open reduction and internal fixation of ankle fractures in patients with positive urine drug screen.

We conducted a study to identify complications associated with open treatment of ankle fractures in patients who tested positive for illicit drugs on urine drug screen (UDS). We hypothesized that patients who had a history of positive UDS and underwent open reduction and internal fixation of an ankle fracture would have a higher incidence of major and minor complications. We retrospectively reviewed the cases of 142 patients who had surgical stabilization of an ankle fracture during a 3-year period. Patients with a history of positive UDS were compared with matched controls with negative UDS. Outcomes measures included nonunion, malunion, and superficial or deep infection. Fisher exact test, Wilcoxon rank sum test, and univariate logistic regression were used to determine statistical significance. There were no significant differences in age, sex, fracture type, incidence of diabetes, or incidence of open fracture between the groups. Incidence of nonunion was higher in patients with positive UDS (P = .01), as was incidence of deep infection (P = .05). Incidence of pooled major complications was also higher in positive UDS patients (P = .03). Patients with a history of illicit drug use, as evidenced by positive UDS, are at increased risk for perioperative complications during treatment for ankle fracture.

Individualized antibiotic prophylaxis reduces surgical site infections by gram-negative bacteria in instrumented spinal surgery.

PURPOSE: Surgical site infection (SSI) can be a challenging complication after posterior spinal fusion and instrumentation (PSFI). An increasing rate of SSI by gram-negative bacteria (GNB) has been observed. Current guideline recommendations have not been effective for preventing infection by these microorganisms. METHODS: Retrospective cohort study comparing two consecutive groups of patients undergoing PSFI at a single institution. Cohort A includes 236 patients, operated between January 2006 and March 2007, receiving standard preoperative antibiotic prophylaxis with cefazolin (clindamycin in allergic patients). Cohort B includes 223 patients operated between January and December 2009, receiving individualized antibiotic prophylaxis and treatment based on preoperative urine culture. Cultures were done 3-5 days before surgery in patients meeting one of the following risk criteria for urinary tract colonization: hospitalization longer than 7 days, indwelling catheter, neurogenic bladder, history of urinary incontinence, or history of recurrent urinary tract infection. RESULTS: Twenty-two (9.3%) patients in cohort A developed SSI, 68.2% due to GNB. 38 (17%) patients in cohort B were considered at risk for GNB colonization; preoperative urine culture was positive in 14 (36%). After adjusted antibiotic prophylaxis, 15 (6.27%) patients in cohort B developed SSI, 33.4% due to GNB. A statistically significant reduction in GNB SSI was seen in cohort B (Fisher's exact test, p = 0.039). CONCLUSION: Higher preoperative GNB colonization rates were found in patients with neurogenic bladder or indwelling catheters. Preoperative bacteriological screening, treatment for bacteriuria, and individualized antibiotic prophylaxis were effective for reducing GNB SSI.

Efficacy of limited cefuroxime prophylaxis in pediatric patients after cardiovascular surgery.

PURPOSE. The efficacy of limited cefuroxime prophylaxis in pediatric patients after cardiovascular surgery was evaluated. METHODS. All patients age 18 years or younger who underwent cardiovascular surgery and received postoperative care from the cardiovascular surgery team between February and July 2006 (preintervention group) and between August 2006 and January 2007 (postintervention group) were eligible for study inclusion. Patients were excluded if they did not receive cefuroxime as postoperative prophylaxis, had a preexisting infection, underwent cardiac transplantation or extracorporeal membrane oxygenation, or underwent delayed sternal closure. The preintervention group received prolonged cefuroxime prophylaxis, and the postintervention group received 24 hours of cefuroxime prophylaxis. Data collected included patient demographics and clinical and laboratory markers of infection, as well as microbiological evidence of and treatment courses for documented or presumed infections. RESULTS. A total of 210 patients were enrolled in the study. The number of patients who required additional antibiotics for suspicion of clinical infection did not significantly differ between the preintervention and postintervention groups (18.6% versus 26.9%, respectively), nor did the rate of documented infection (bacteremia, urinary tract infection, endocarditis, sepsis) (42.1% versus 48.3%, respectively). Moreover, indications for the antibiotics initiated were similar between the preintervention and postintervention groups. Clinical and laboratory signs of postoperative infection were similar between groups. There were no differences in postoperative white blood cell counts, peak serum glucose levels, and platelet nadir between groups. CONCLUSION. Limiting postoperative cefuroxime prophylaxis to 24 hours did not increase infectious outcomes in pediatric patients.

[Laboratory studies of the urine in suppurative surgical infection in cattle]. / Niakoi laboratorni izsledvaniia na urinata pri gnoina khirurgicheska infektsiia u govedoto.

One hundred and eight cattle (20 controls, 14 with an experimentally induced and 74 with spontaneously occurred suppurative surgery infection) were studied in terms of their general condition and some of the urine indices--pH, specific weight, proteins, urobillinogen, acetone, sugar, blood, urea and sediment. It was established that when the general status deteriorated and death occurred the urine pH value rose (by 1--1.5), and the specific weight was 0.005--0.010 higher, while the level of urina urea dropped by 0.5--0.6 g%. In 89 per cent of the investigated animals there were 0.1 per percent proteins, and the sediment consisted of 20--30 erythrocytes, from sporadic to 10-12 leucocytes, and from single to 5--6 kidney epithelium cells per field. In 38.8 per cent of the cattle affected with suppurative processes there were tripelphosphates in the sediment. Urobillinogen was found in 63.6 per cent of the cases. Suppurative infections caused by Corynebacterium pyogenes are accompanied by greater changes in the sediment. In almost all of the recovered animals the urine indices came back to normal.