Affinity of Staphylococcus epidermidis to various prosthetic graft materials.

BACKGROUND: Abdominal wall hernias have always been a major problem for general surgeons. The techniques of repairing primary, recurrent, and incisional hernias have evolved throughout the years at an accelerating trend, especially after production of prosthetic graft materials. Although looked upon with suspicion due to infection, fistula formation, and foreign body reaction, prosthetic graft materials are used deliberately in primary and recurrent hernias. The present study was designed to evaluate bacterial adherence to frequently used prosthetic graft materials. MATERIALS AND METHODS: The study was carried out in five different groups with each group consisting of 10 identical samples of the same kind of prosthetic graft material. The prosthetic graft materials used in the study were polypropylene, polyglactin 910, polyester fibers, steel, and polytetrafluoroethylene (PTFE). These prosthetic graft materials were incubated in vitro with a Staphylococcus epidermidis strain which was ++++ adhesion positive. The degree of adhesion of S. epidermidis to prosthetic graft materials was assessed by the ELISA method. RESULTS: Vicryl grafts showed significantly minimal bacterial adhesion whereas PTFE grafts tended to have more adhesion but this did not reach a statistical significance. Other graft materials did not show any difference for bacterial adhesion (Table 3). CONCLUSION: These results suggest that in vitro S. epidermidis adhesion to Vicryl grafts is less than other types of prosthetic graft materials (P < 0.05 for all comparisons). Further in vitro and in vivo studies are required to confirm these results and to understand the complex interactions among bacteria, graft material, microenvironment, and surgical technique.

Effect of single-dose prophylactic ampicillin and sulbactam on wound infection after tension-free inguinal hernia repair with polypropylene mesh: the randomized, double-blind, prospective trial.

OBJECTIVE: To assess the value of single-dose, intravenous, prophylactic ampicillin and sulbactam (AS) in the prevention of wound infections during open prosthetic inguinal hernia repair by a double-blind, prospective, randomized trial. SUMMARY BACKGROUND DATA: The use of antibiotic prophylaxis during open prosthetic inguinal hernia surgery is controversial, and no prospective trial has been conducted to examine this issue. METHODS: Patients undergoing unilateral, primary inguinal hernia repair electively with the Lichtenstein technique using polypropylene mesh were randomized to receive 1.5 g intravenous AS before the incision or an equal volume of placebo according to a predetermined code of which the surgeons were unaware. Patients with recurrent, femoral, bilateral, giant, or incarcerated hernias or any systemic diseases were excluded. Age, sex, body mass index, American Society of Anesthesiologists score, type of hernia, type of anesthesia, duration of surgery, and use of drains were recorded. Infection was defined according to the criteria of Centers for Disease Control. Patients were evaluated 1 week, 1 month, 6 months, and 1 year after surgery by an independent surgeon. All complications were recorded. Results were assessed using chi-square, Fisher's exact, and Student t tests as appropriate. RESULTS: Between September 1996 and July 1998, 280 patients (140 AS, 140 placebo group) entered the protocol. Four patients from the AS group and seven from the placebo group were excluded because of inadvertent antibiotic administration or follow-up problems. Groups were well matched for all the variables studied and postoperative complications, excluding wound infections, which occurred at a rate of 0.7% in the AS group and 9% in the placebo group (P =.00153). Twelve patients in the placebo group developed wound infections, requiring five repeat hospital admissions in three patients. These three patients suffered deep infections reaching the graft, which resulted in graft loss in two. The single infected patient in the AS group had his graft removed as well because of deep persistent infection. CONCLUSIONS: This study documented a significant (10-fold) decrease in overall wound infections when single-dose, intravenous AS was used during Lichtenstein hernia repair. Deep infections and wound infection-related readmissions were also reduced by the use of AS. Proponents of mesh repairs may therefore be advised to use prophylactic single-dose intravenous antibiotic coverage in the light of the results of this trial. AS proved to be an effective antimicrobial agent.

Does technique of anastomosis play any role in developing late perianal abscess or fistula?

PURPOSE: This study examines the risk factors for developing perianal abscess or fistula formation after ileal pouch-anal anastomosis procedure for chronic ulcerative colitis or familial adenomatous polyposis. METHODS: A total of 1,457 patients with J-pouch, 1,304 (89.5 percent) with chronic ulcerative colitis and 153 (10.5 percent) with familial adenomatous polyposis who had a two-stage procedure without any evidence of previous perianal disease were included in the study. The effect of pouch-to-anal anastomosis type on perianal abscess or fistula formation was evaluated. RESULTS: A total of 108 patients (7.4 percent) had a perianal abscess or fistula after the ileal pouch-anal anastomosis procedure after at least one year of follow-up. No statistically significant difference was identified in fistula formation regarding the age and gender of the patients (P > 0.05), nor did the risk of fistula formation differ significantly between the patients with handsewn vs. stapled anastomoses (P > 0.05). However, patients with a diagnosis of chronic ulcerative colitis, compared with patients with familial adenomatous polyposis, had a statistically higher risk of developing abscess or fistula (P = 0.012). CONCLUSION: The most important risk factor in developing perianal sepsis in long-term patients with ileal pouch-anal anastomosis is the initial disease type. After excluding patients without Crohn's disease, the risk of developing an abscess or fistula was found to be significantly greater in patients with chronic ulcerative colitis compared with patients with familial adenomatous polyposis, and this risk is independent of anastomotic technique.

Recurrence after incisional hernia repair: results and risk factors.

A relatively low success rate in recurrent incisional hernia repair has prompted us to review the effects of certain risk factors on the long-term outcome of our cases. In this study, 109 recurrent incisional hernias were repaired and reviewed between 7 and 92 months after the operation. The recurrence rate was 45.0%. Many conditions that have been implicated as causal factors in the occurrence of incisional hernias were not found to be associated with recurrence after repair. However, chronic constipation was determined to be the most prominent risk factor associated with late recurrence.

Core needle biopsy in renal transplantation.

Core biopsies have been done by ultrasound assisted 18-G disposable needles with a spring loaded gun (Biopty) system in 140 renal transplant cases either for investigation of an early non-functioning graft or evaluation of deteriorating graft functions. The biopsy procedure was successfully completed in 99.5% and sufficient amount of renal tissue was obtained in 88% of cases. The pathological diagnoses were confirmed 100% by the other clinical parameters of cases with acute cellular rejection, pyelonephritis, acute tubular necrosis and there was disease recurrence. In another 8 patients (6%) where the pathological picture was showing either no or nonspecific changes there was no major change in clinical outcome. In addition, clinical diagnoses of chronic vascular rejection and Cyclosporin A toxicity were confirmed in 93.7% and 91.7%, respectively, in biopsies of these cases. Complications were seen in 3 patients as a bowel perforation, intra-abdominal bleeding and formation of an intrarenal arterio-venous fistula. In former two complicated cases there was no need for any extra treatment but the arterio-venous fistula was successfully embolized through an angiography catheter without losing the graft. We conclude that the Biopty system is more efficient than the fine needle aspiration biopsy especially when the pathological diagnosis can be made upon tissue components rather than cells alone.

Human T cells expressing V beta 8 do not predominantly recognize DR2 alloantigen.

A panel of seven monoclonal antibodies recognizing human T-cell antigen receptor (TcR) V alpha or V beta subsets has been used to measure TcR gene expression in peripheral blood lymphocytes and mixed lymphocyte culture responses (MLR) between DR2- and DR2+ (DRw15+) donors. There were no significant differences between DR2- and DR2+ donors in per cent T cells in fresh peripheral blood labelled with any of these antibodies, which included an antibody recognizing V beta 8. This indicates strongly that increased negative selection of V beta 8+ T cells does not occur in DR2+ compared with DR2- individuals. In MLR between DR2- and DR2+ donors the only significant change compared with fresh peripheral lymphocytes was that T cells expressing V beta 5.1 were decreased in DR2- lymphocyte populations responding to DR2 alloantigen. No changes in levels of V beta 8+ T cells were detected in MLR between DR2- and DR2+ donors. This suggests that V beta 8+ T cells are not predominantly reactive against DR2 (DRw15). The data support the concept that alloreactivity against a single class II major histocompatibility complex (MHC) mismatch is mediated by T cells expressing a range of different TcR V beta molecules.

T-cell receptor Vbeta gene usage by lymphocytes infiltrating human renal allografts.

T cell lines have been derived from human kidney allograft biopsies using mitogenic stimulation. Southern blotting using a T-cell receptor (TCR) Cbeta probe revealed an oligoclonal pattern of rearranged bands in all 12 samples analysed. In some cases, differences in band patterns were noted between independent cultures from the same biopsy. Most T-cell clones derived from 2 biopsies showed different patterns of rearranged bands. The polymerase chain reaction (PCR) was used to study TCR Vbeta gene usage in allograft-derived T-cell cultures. This was more sensitive and more informative than Southern blotting and revealed that most TCR Vbeta genes were expressed in T cells from biopsies showing cellular rejection. The potential usefulness of this technique to quantify TCR V gene usage in allospecific T-cell populations is discussed.