Yi-Horng Lee

Importance of Colonization Site in the Current Epidemic of Staphylococcal Skin Abscesses

OBJECTIVE: The goal was to compare rectal and nasal Staphylococcus aureus colonization rates and S aureus pulsed-field types (PFTs) for children with S aureus skin and soft-tissue abscesses and normal control subjects. METHODS: Sixty consecutive children with S aureus skin and soft-tissue abscesses that required surgical drainage and 90 control subjects were enrolled. Cultures of the nares and rectum were taken in both groups. S aureus isolates from all sites were characterized through multiple-locus, variable-number, tandem-repeat analysis, pulsed-field gel electrophoresis, staphylococcal cassette chromosome mec typing for methicillin-resistant S aureus isolates, and determination of the presence of Panton-Valentine leukocidin genes. RESULTS: S aureus was detected significantly more often in the rectum of children with abscesses (47%) compared with those in the control group (1%; P = .0001). Rates of nasal colonization with S aureus were equivalent for children with abscesses (27%) and control subjects (20%; P = .33). S aureus recovered from the rectum was identical to S aureus in the abscess in 88% of cases, compared with 75% of nasal isolates. PFT USA300, staphylococcal cassette chromosome mec type IV, and Panton-Valentine leukocidin genes were significantly increased in the S aureus isolates from children with abscesses compared with those from control subjects. CONCLUSIONS: Skin and soft-tissue abscesses in the current epidemic of community-associated staphylococcal disease are strongly associated with rectal colonization by PFT USA300. Nasal colonization in children does not seem to be a risk factor.

An alternative to open incision and drainage for community-acquired soft tissue abscesses in children

BACKGROUND The continually rising incidence of soft tissue abscesses in children has prompted us to seek an alternative to the traditional open incision and drainage (I&D) that would minimize the pain associated with packing during dressing changes and eliminate the need for home nursing care. STUDY DESIGN A retrospective review of all patients with soft tissue abscesses from November 2007 to June 2008 was conducted after institutional review board approval. Patients who were treated with open I&D were compared to those treated with placement of subcutaneous drains through the abscess cavities. Both groups received equivalent antibiotic treatment, and all patients were followed in outpatient clinics until infection resolved. The demographics, presenting temperature, culture results, and outcomes were compared between these 2 groups. RESULTS A total of 219 patients were identified; 134 of them underwent open I&D, whereas 85 were treated with subcutaneous drains. The demographics, anatomical location of the abscesses, and bacteriology were comparable between the 2 groups. There were equal number of patients in each group who presented with fever initially. Of those treated with open I&D, 4 had metachronous recurring abscesses within the same anatomical region and 1 patient required an additional procedure because of incomplete drainage. There were no recurrences or incomplete drainages in the subcutaneous drain group. The cosmetic appearance of the healed wound from subcutaneous drain placement during the immediate follow-up period is better than that of an open I&D. CONCLUSIONS Placement of a subcutaneous drain for community-acquired soft tissue abscesses in children is a safe and equally effective alternative to the traditional I&D.

Outcome Differences Between Gastroschisis Repair Methods

BACKGROUND Gastroschisis is a congenital abdominal wall defect that is repaired with either a primary closure or staged closure. The outcome of these infants may differ because of different closure techniques. In addition to the usual markers of parenteral nutrition (PN) use and length of stay (LOS) as outcome measures, we examined the duration of postoperative acidosis and positive fluid balance as markers for postoperative stress associated with these two techniques. METHODS A retrospective review of newborns with gastroschisis was conducted at a free-standing childrens hospital from 2002 to 2008. The demographic data, gestational age, birth weight, operative reports, days on PN, LOS, duration of postoperative acidosis and fluid balances were reviewed. Data were analyzed using the Fishers exact test or unpaired t test. RESULTS Thirty-two infants with gastroschisis were identified. One was excluded from analysis due to incomplete follow-up. The patients were classified as either primary closure (n = 8) or staged repair (n = 23). There was one death in our series. Patients who underwent primary closure had significantly older gestational age and higher birth weight. Primary closure is associated with significantly less duration of postoperative metabolic acidosis and fewer days with positive fluid balance. Patients who had primary repair also had less parenteral nutrition use and shorter length of hospitalization, though not statistically significant. Gastroschisis with associated intestinal atresia was more likely to be repaired with staged closures. CONCLUSIONS There are physiologic advantages to primary repair of gastroschisis that can lead to better outcome, but the indications for the choices of closure technique remain unclear. Primary closure should be used when possible.

Early experience with the use of rhomboid excision and Limberg flap in 16 adolescents with pilonidal disease

BACKGROUND Rhomboid excision with Limberg flap (RELF) repair has been shown to be effective in the management of pilonidal disease (PD) in adults. Wide excision allows complete removal of diseased tissue, and the rotational flap allows tensionless coverage as well as helps flatten the natal crease, which is believed to contribute to the recurrence of PD. METHODS This study is a retrospective review of all adolescents who underwent excision of pilonidal disease using RELF at a single institution for a period of 18 months. RESULTS Sixteen adolescents with PD were treated with RELF during this period. All procedures were completed with no intraoperative complications. Mean operative time and hospital stay were 92 +/- 30 minutes and 1.8 +/- 0.29 days, respectively. Mean follow-up was 11 +/- 6.0 months. One patient had recurrence of his disease, and one needed prolonged wound care after wound breakdown. Six others had minor complications including 4 patients (25%) who had superficial wound separation that resolved promptly with dressing change. One patient had a superficial wound infection. One patient had residual pain. CONCLUSION Rhomboid excision with Limberg flap is effective in the management of PD in adolescents. The 6% recurrence rate is similar to that reported in the adult literature. Despite the limitations of this study, the low morbidity, hospital stay, and recurrence rate noted with our initial experience are very encouraging.

Transluminal migration of ingested foreign body without peritonitis.

The authors present 2 cases of transluminal migration of an ingested foreign body into the peritoneal cavity without causing peritonitis. Clinical and radiologic features and surgical approach are described, focusing on the absence of an acute abdomen in transluminal migration and the use of laparoscopy in achieving extraction of the foreign object.

A semiquantitative PCR technique for detecting chimerism in hamster-to-rat bone marrow xenotransplantation

Although bone marrow transplantation has been used to induce donor-specific tolerance in many allogeneic models, similar effort in xenogeneic transplantation is met with obstacles like more severe graft versus host disease (GVHD). We are currently engaged in developing a GVHD-free hamster-to-rat xenotransplantation model using splenectomy, total body irradiation, and donor bone marrow transplantation. To test donor cell chimerism, particularly in the solid tissues, we developed a semiquantitative polymerase chain reaction (PCR) method using primers specific for hamster beta-actin and mitochondrial cytochrome C oxidase I and II (MCO I and II) genes and rat sex determination region on the Y chromosome (SRY) gene. Using this method, we estimated the level of hamster cells chimerism in rats subjected to splenectomy, total body irradiation (10 Gy), and hamster bone marrow transplantation (3 x 10(8) cell/recipient) and observed high levels of donor cells in all recipient tissues tested.

Hamster-to-rat bone marrow xenotransplantation and humoral graft vs. host disease

Abstract: Bone marrow transplantation (BMT) may induce tolerance across xenogeneic barriers. We have established a xenogeneic BMT model where hamster BM is transplanted into splenectomized LEW rat recipients resulting in high levels of engraftment. Unfortunately, graft vs. host disease (GVHD) with severe dermatitis developed in all rat recipients. We were successful in treating or preventing the dermatitis of this xenogeneic GVHD by the use of the T‐cell suppressant tacrolimus. However, this compound did not prevent the development of a fatal liver injury in the rat recipients. This study was designed to elucidate the pathogenesis of this liver injury appearing in T‐cell suppressed rat recipients of hamster BM.

Staphylococcal colonization of caretakers of children who have community-acquired skin and soft tissue infections

PURPOSE Colonization with Staphylococcus aureus is considered a risk factor for the rising incidence of pediatric community-acquired skin and soft tissue infections (CA-SSTIs), and intrafamily spread is thought to be the source of colonization. METHODS A prospective study was conducted to determine skin and nasal staphylococcal colonization rates among the caretakers of CA-SSTI patients and those of nonabscess controls. A questionnaire regarding risk factors was administered to all participants. Fishers Exact test and the chi(2) test were used for statistical analysis. RESULTS Forty-six patients and their caretakers were enrolled in both the study and control groups. Of the caretakers in the study group, 19.6% (n = 9) had staphylococcal colonization of nares; and 2.2% (n = 1), skin. In the control group, 17.4% (n = 8) had nasal colonization; and none had skin colonization. Of the children in the study group, 58.7% (n = 27) had a family history of CA-SSTI compared with only 17.4% (n = 8) of controls (P = .0001). Of CA-SSTI patients, 45.7% (n = 21) had prior abscesses compared with 6.5% (n = 3) of controls (P = .0001). No other risk factor was identified. CONCLUSION There was no increase in nasal or skin staphylococcal colonization among caretakers of children with CA-SSTI. Family and personal histories of CA-SSTI were the only identified risk factors for CA-SSTI.

Concordant hamster-to-rat liver xenotransplantation leads to hyperlipidemia

Different species have adapted in different ways to their environment through the variation of specific metabolic parameters. For example, hamsters, unlike rats, are able to adjust their metabolism when they are subjected to extreme temperatures, modifying the mobilization of fat and regulating its storage.1 Knowing that the liver plays a primary role in lipid metabolism, we performed liver transplantation between hamsters and rats to determine what effects this might have in recipient cholesterol and trygliceride levels.

Xenogeneic Humoral Graft-Vs-Host Disease Following Hamster-to-Rat Bone Marrow Transplantation

Bone marrow transplantation (BMT) is an effective strategy to induce tolerance across xenogeneic barriers.1 This approach has been used in the hamster-to-rat BMT model.2 However, all animals suffered from graft-vs-host disease (GVHD). Although xenogeneic GVHD has been observed in other studies, it is not yet well characterized.3 Because xenograft rejection is primarily mediated by humoral mechanisms, we tested the hypothesis that, unlike allogeneic GVHD in which cellular mechanisms predominate, xenogeneic GVHD could also be humorally mediated.