Effect of bone biopsy in guiding antimicrobial therapy for osteomyelitis complicating open wounds.

BACKGROUND: Osteomyelitis associated with infected overlying wounds represents a difficult diagnostic and therapeutic problem; bone biopsies can be done during debridement of the overlying wounds, but it is unclear how often the results of these bone cultures actually affect subsequent antibiotic decisions. The present study was undertaken to evaluate the usefulness of bone biopsies in guiding antibiotic therapy for this type of osteomyelitis. METHODS: Culture results of 44 bone biopsies taken during surgical debridement in 41 patients over the period from June 1994 to August 1998 were compared with those from the overlying wounds to determine whether the data affected the subsequent choice of antibiotics. The study design was that of a retrospective chart review in which the standard operative and microbiological procedures in place at the Milwaukee Veterans Affairs Medical Center were used. RESULTS: Sixty-one wound and 55 bone isolates were obtained during this study. Thirty-one isolates were found in bone, but not the overlying wound; diphtheroids were the most common organism obtained in this fashion. Correlation between wound and bone isolates was generally poor. Antibiotics were subsequently changed in 20 of the 44 cases after results of the bone biopsy became known, with the bone isolates already being covered in 10 cases and the bone biopsy results ignored in 14 cases. CONCLUSION: Because bone biopsy results seem to aid in tailoring antibiotic therapy in almost half the cases when bone is sampled during wound debridement surgery, this technique may be very helpful in certain cases and should be regularly undertaken when these procedures are carried out.

An objective analysis of process errors in trauma resuscitations.

OBJECTIVE: A computer-based system to apply trauma resuscitation protocols to patients with penetrating thoracoabdominal trauma was previously validated for 97 consecutive patients at a Level 1 trauma center by a panel of the trauma attendings and further refined by a panel of national trauma experts. The purpose of this article is to describe how this system is now used to objectively critique the actual care given to those patients for process errors in reasoning, independent of outcome. METHODS: A chronological narrative of the care of each patient was presented to the computer program. The actual care was compared with the validated computer protocols at each decision point and differences were classified by a predetermined scoring system from 0 to 100, based on the potential impact on outcome, as critical/noncritical/no errors of commission, omission, or procedure selection. RESULTS: Errors in reasoning occurred in 100% of the 97 cases studied, averaging 11.9/case. Errors of omission were more prevalent than errors of commission (2. 4 errors/case vs 1.2) and were of greater severity (19.4/error vs 5. 1). The largest number of errors involved the failure to record, and perhaps observe, beside information relevant to the reasoning process, an average of 7.4 missing items/patient. Only 2 of the 10 adverse outcomes were judged to be potentially related to errors of reasoning. CONCLUSIONS: Process errors in reasoning were ubiquitous, occurring in every case, although they were infrequently judged to be potentially related to an adverse outcome. Errors of omission were assessed to be more severe. The most common error was failure to consider, or document, available relevant information in the selection of appropriate care.

On-line quality [corrected] assurance in the initial definitive management of multiple trauma: evaluating system potential.

The TraumAID system has been designed to provide on-line decision support throughout the initial definitive management of injured patients. Here we describe its retrospective evaluation and the use we subsequently made of judges comments on the validation data to evaluate TraumaTIQ, a new critiquing interface for TraumAID, investigating the question of whether, with timely recording of information, a system could produce commentary in line with that of human experts. Our results show that (1) comparable commentary can be produced, and (2) validation studies, which take great time and effort to conduct, can produce useful data beyond their original design goals.

Cutaneous defenses against dermatophytes and yeasts.

Predispositions to the superficial mycoses include warmth and moisture, natural or iatrogenic immunosuppression, and perhaps some degree of inherited susceptibility. Some of these infections elicit a greater inflammatory response than others, and the noninflammatory ones are generally more chronic. The immune system is involved in the defense against these infections, and cell-mediated immunity appears to be particularly important. The mechanisms involved in generating immunologic reactions in the skin are complex, with epidermal Langerhans cells, other dendritic cells, lymphocytes, microvascular endothelial cells, and the keratinocytes themselves all participating in one way or another. A variety of defects in the immunologic response to the superficial mycoses have been described. In some cases the defect may be preexistent, whereas in others the infection itself may interfere with protective cell-mediated immune responses against the organisms. A number of different mechanisms may underlie these immunologic defects and lead to the development of chronic superficial fungal infection in individual patients. Although the immunologic defects appear to be involved in the chronicity of certain types of cutaneous fungal infections, treatment of these defects remains experimental at the present time.

Effect of abscess fluid supernatants on the kinetics of Candida albicans growth.

Abscess fluid supernatants have been found to inhibit microbial growth, an effect that appears to be due to a protein originating in the cytoplasm of neutrophils. The antimicrobial activity of calprotectin, the responsible protein, is reversible by the addition of zinc to the culture medium. To more carefully analyze this type of antimicrobial activity supernatants of fluids from experimental subcutaneous Candida albicans abscesses in mice were studied to determine how they affect the in vitro growth kinetics of C. albicans. The abscess fluid supernatants inhibited growth in a dose-dependent fashion and more at early times than at later ones. Instability of the abscess fluid antimicrobial activity did not appear to explain the timing of the growth inhibition. A marked lengthening of the lag phase of growth was observed in cultures containing the supernatants (from approximately 6 hr in the control cultures to 15-20 hr in those with the supernatants). On the other hand, the abscess fluid supernatants had only minimal effects on the generation times of actively proliferating C. albicans yeast cells. In addition, these supernatants did not appear to significantly affect the percentage of inoculated organisms undergoing cell division, as determined by a limiting dilution assay. Therefore, these results indicate that abscess fluid supernatants extend the lag phase of C. albicans growth, an effect similar to that seen with zinc-deprived organisms.

Proposed core content for pediatric emergency medicine fellowship training of emergency medicine graduates.

The establishment of pediatric emergency medicine as a subspecialty of emergency medicine has engendered the need for closer examination and development of guidelines for fellowship training. Core content and curriculum documents pertaining to fellowship training in pediatric emergency medicine for pediatric graduates have been published previously. However, the educational needs of emergency medicine graduates for such training are significantly different from those of pediatric graduates in several important respects. We believe that emergency physicians should take an active role in the creation and refinement of educational guidelines for fellowship training in pediatric emergency medicine for emergency medicine graduates. For this reason, we present a proposed core content outline in the hope that it will serve to foster this process.

Proteinuria as a biomarker: risk of subsequent morbidity and mortality.

A standard laboratory renal assessment, concentration of albumin in urine, has been suggested as a biomarker of renal damage, but little data exist on its ability to predict health outcomes in the general population. This 16-year follow-up study of a general population evaluated the utility of this assessment to predict subsequent serious health consequences. Four percent of men and 2% of women aged 45-74 years exhibited proteinuria in a cross-sectional screening of an ambulatory population, with the percentage increasing with age. The finding of proteinuria was predictive of serious health consequences, with adjusted relative risks for subsequent mortality of 1.71 for men and 1.84 for women and adjusted relative risks for renal disease incidence of 3.46 in men and 1.39 in women. Controlling for those factors which might be associated with proteinuria and even excluding early cases did not alter these findings. These data support that causal proteinuria should be considered as a marker for risk of poor health outcomes.

Comparison of the metal-binding anticandidal activities of serum and abscess fluid supernatants.

Serum transferrin appears to play a role in host defense by competing with invading microorganisms for iron. The purpose of the present study was to compare this activity to a similar one recently described in abscess fluids and based on a calcium- and zinc-binding protein called calprotectin. Serum and abscess fluid supernatants were collected and pooled from groups of five to 10 C57BL/6 mice with experimental Candida albicans abscesses; serum was also collected from normal animals. In four experiments, serum was found to reduce in vitro C. albicans growth in Sabouraud glucose broth by a mean of 97.9% at 10 mg ml-1 of protein; this effect was reversed by adding 3-10 microM FeCl3, but not by similar amounts of ZnSO4. Abscess fluid supernatants had a greater effect, reducing growth by 99.9% at 1 mg ml-1 and 76.1% at 0.1 mg ml-1 of total protein; this effect was reversed by 3-10 microM ZnSO4, but not FeCl3. Although abscess fluid supernatants were effective when high inocula (10,000 yeast cells) were used, serum from the infected mice inhibited growth only with lower inocula (10-100 yeast cells). In a separate study, serum from infected mice (eight pools) reduced growth (by a range of 36 to 97%), whereas serum from normal mice (five pools) actually enhanced growth in this system (by a range of 173 to 595%).(ABSTRACT TRUNCATED AT 250 WORDS)

Arrays of Candida albicans pseudohyphae that protect the organisms from neutrophil fungicidal mechanisms in experimental infections of mice.

Experimental subcutaneous Candida albicans infections in mice were used to examine the manner in which this pathogen is cleared in animals recovering from cyclophosphamide-induced leucopenia. In this system, infections at the inoculation sites progressed rapidly during a 6 day period of leucopenia to form arrays of parallel filamentous organisms that effectively isolated those in the interior from contact by neutrophils, even when the leucopenia had resolved. Dense collections of organisms also developed at sites of metastatic infection in the kidneys. A majority of the organisms were found to be viable when they were retrieved from the infected subcutaneous sites of animals that had recovered from leucopenia and whose abscesses had begun to drain spontaneously. Removal of the protective arrays of fungal cells appeared to be accomplished by drainage of abscess contents through the surface of the skin or into the collecting system of the kidney. Drainage of the subcutaneous abscesses did not occur in the cyclophosphamide-treated animals until after the neutrophilic infiltrates had developed, suggesting that this drainage process was mediated by neutrophils rather than by the organisms themselves. In summary, the above findings demonstrate that C. albicans infections in leucopenic hosts may progress to the extent that they would be very difficult to clear solely through the microbicidal processes of returning neutrophils. However, neutrophils also appear to promote the removal of masses of viable fungal cells to the exterior of the body.

Proposed fellowship training program in pediatric emergency medicine for emergency medicine graduates.

Interest in pediatric emergency medicine has grown steadily during the past decade among pediatricians and emergency physicians. With the rapid proliferation of pediatric emergency medicine programs for pediatricians has come extensive and valuable experience with this type of fellowship education. As a result, the structure and scope of these programs have become increasingly well established. Because the number of pediatric emergency medicine fellowship programs for emergency physicians has yet to reach "critical mass," no similar de facto standards exist for these programs. The recent establishment of guidelines for pediatric emergency medicine subspecialty certification by the American Board of Emergency Medicine and the American Board of Pediatrics brings new importance to fostering such standards for the training for emergency physicians. To this end, we present a proposed pediatric emergency medicine fellowship program developed during a retreat that included physicians from an emergency medicine program and two pediatric hospitals. We also review some of the significant events that have occurred in the evolution of pediatric emergency care.

Inefficiency of in vivo candidacidal mechanisms in experimental subcutaneous infections with Candida albicans in mice.

A murine model of subcutaneous Candida albicans infections was used to evaluate host defenses against inocula of from 10(1) to 10(8) yeast cells. In these experiments, small inocula did not produce abscesses that drained to the skin surface, whereas larger ones did. Also, small numbers of organisms often remained at the infected sites for up to 21 days after inoculation with either small or large numbers of organisms. The data from these studies suggest that the in vivo candidacidal mechanisms in these infections are relatively inefficient and that they therefore may require some additional mechanism to control proliferation of the remaining organisms.

Characterization of common variable immunodeficiency: identification of a subset of patients with distinctive immunophenotypic and clinical features.

The peripheral blood lymphocyte surface markers and clinical features of 38 patients with common variable immunodeficiency (CVID) were assessed. These studies identified a subset of CVID consisting of 14 of the 38 patients with a distinctive T-cell immunophenotype and clinical findings. The phenotypic changes were characterized by an abnormally low CD4/CD8 ratio (less than or equal to 0.9) due primarily to a significant increase in CD8 T cells. In addition, there was an expansion in CD8 T cells coexpressing CD57 and increased expression of the activation markers HLA-DR and interleukin-2 receptor (IL-2R) by these cells. This group of immunophenotypically abnormal CVID patients also had characteristic clinical features, including splenomegaly (P less than .02) and in vivo T-cell dysfunction based on the evaluation of delayed-type hypersensitivity (P less than .05). Approximately 71% of these patients had splenomegaly and 42% were anergic in contrast to the remaining group of CVID patients, in which 29% had splenomegaly and 7% were anergic. These findings define a subgroup of CVID patients that have specific immunophenotypic features and functional T-cell abnormalities.

Studies of human leprosy lesions in situ using suction-induced blisters. 2. Cell changes and soluble interleukin 2 receptor (Tac peptide) in reversal reactions.

To examine the pathogenesis of type 1 (reversal) reactions in leprosy, we studied cellular and soluble immunologic components of skin lesions in 10 patients with reactions, 24 active patients without reactions, and 33 control patients whose leprosy had been treated and cured. Cells and Tac-peptide levels were obtained from fluid aspirated from blisters induced by suction directly over representative skin lesions. During reversal reactions: a) the lesions contained an increased number and percentage of CD4+ (T-helper) cells; b) Tac-peptide levels were elevated in half of the lesions; c) the increases in Tac peptide and CD4+ cells were directly correlated; and d) systemic administration of corticosteroids appeared to cause a reduction in the intralesional CD4+ cell population. These findings were localized to the skin, and do not represent simple filtration of these components from the peripheral blood. We conclude that spontaneous lymphocyte activation in situ, primarily of CD4+ cells, is an important feature of reversal reactions, and may be an intermittent or cyclic phenomenon during the reaction. Findings in active patients without reactions are consistent with the hypothesis that differing states of immunologic equilibrium have been established in different portions of the leprosy spectrum. In reversal reactions we may, therefore, be examining immunologic processes set in motion when a pre-existing equilibrium has been upset by spontaneous, natural events. The mechanism of such spontaneous changes in immunity in leprosy is of considerable interest, not only to understand the reaction, but also to examine the underlying determinants of delayed-type hypersensitivity and cell-mediated immunity in leprosy and the potential for artificially manipulating these responses, as proposed with vaccines or immunotherapy.

Cellular source of soluble interleukin 2 receptors in serum of mice after recombinant interleukin 2 administration.

Previous studies have shown that peripheral blood mononuclear cells activated in vitro not only express cell-associated interleukin 2 receptors (IL2R) but also release a soluble form of this receptor. In this study, we demonstrate that administration of human recombinant IL 2 (rIL 2) to mice results in increased spleen weights, splenic natural killer (NK) cell cytolytic activity, and serum levels of soluble IL2R. However, compared with rIL 2-treated heterozygote controls, beige mice treated with rIL 2 displayed similar elevations in serum soluble IL2R but significantly less splenic NK activity. Likewise, administration of anti-asialo GM1 antiserum to rIL 2-treated mice resulted in a dramatic reduction in splenic NK cytolytic activity, but no reduction in serum soluble IL2R. Conversely, while rIL 2 treatment of BALB/c mice produced increased splenic NK activity and serum soluble IL2R, similar treatment of BALB/c nude mice resulted in elevation of only splenic NK activity. These studies demonstrate that administration of rIL 2 to normal mice can elevate both serum IL2R levels and splenic NK cytolytic activity. However, the results suggest that T cells are likely to be the source of elevated serum IL2R after rIL 2 administration.

Clinical pharmacokinetics of daptomycin.

Daptomycin is a new lipopeptide antibiotic for which preliminary pharmacokinetic data in adults have been limited to normal healthy volunteers and patients with renal insufficiency. We report the clinical pharmacokinetics of the first and fifth doses of iv daptomycin 150 mg (2 mg/kg) q24h in a 29-year-old man being treated for a gram-positive cellulitis and thrombophlebitis. Individual pharmacokinetic parameters yielded similar results during doses one and five. The pharmacokinetic profile observed in our patient did not markedly differ from data obtained from healthy volunteers.

trans activation of granulocyte-macrophage colony-stimulating factor and the interleukin-2 receptor in transgenic mice carrying the human T-lymphotropic virus type 1 tax gene.

Three lines of transgenic mice carrying the human T-cell lymphotropic virus type 1 tax gene have previously been reported to develop neurofibromas composed of perineural fibroblasts (S. H. Hinrichs, M. Nerenberg, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1340-1343, 1987; M. Nerenberg, S. H. Hinrichs, R. K. Reynolds, G. Khoury, and G. Jay, Science 237:1324-1329, 1987). Tumors from these mice and tumor cell lines derived from them expressed high levels of tax RNA and protein. They also expressed high levels of the granulocyte-macrophage colony-stimulating factor (GM-CSF) gene as measured by proliferative responses of FD-CP1 target cells using conditioned media from tumor cells and by Northern (RNA) blot analysis of RNA from tumors and tumor cell lines. Although other tissues, such as salivary glands and muscles, in the transgenic mice also expressed high levels of tax, they did not express the gene for GM-CSF. This indicates that tissue-specific cellular factors, in addition to tax, are required for GM-CSF gene expression. Systemic effects of excessive GM-CSF production were demonstrated by infiltration of polymorphonuclear leukocytes into tumor tissues which are not necrotic, by peripheral granulocytosis, and by splenomegaly resulting from myeloid hyperplasia. The interleukin-2 (IL-2) receptor was also found to be expressed by the tumors and tumor cell lines as measured by IL-2-binding and cross-linking studies. This is the first demonstration that the IL-2 receptor can be activated by tax in a nonlymphoid cell type. These in vivo findings are consistent with other reports which have demonstrated in vitro cis-regulatory elements within the 5'-flanking regions of the genes for GM-CSF and the IL-2 receptor which are responsive to trans activation by the tax gene.

Serum immunoglobulin G antibody subclass response to respiratory syncytial virus F and G glycoproteins after first, second, and third infections.

Serum samples from 31 children who experienced two or three infections with respiratory syncytial virus (RSV) in the first four years of life were tested in an enzyme-linked immunosorbent assay to examine the immunoglobulin G (IgG) subclass responses to the RSV F and G surface glycoproteins associated with primary infection and reinfection. We sought to determine whether the greater degree of glycosylation of the G glycoprotein was reflected in an IgG subclass immune response more like that to a polysaccharide antigen than to a protein antigen. We found that the IgG1/IgG2 ratio of postinfection antibody titers to F was fourfold higher than that to the G glycoprotein after RSV infections 1, 2, and 3. The IgG2 response to the heavily glycosylated G glycoprotein differed from that to a polysaccharide antigen in that the IgG1/IgG2 ratio remained constant with age, whereas the response to a polysaccharide antigen decreased as the IgG2 response increased with age. We also noted that antibody responses to both surface glycoproteins in the IgG1 and IgG2 subclasses reached their maximum levels after RSV infection 2.

Lymphocyte analysis in a patient with X-linked agammaglobulinemia and isolated growth hormone deficiency after development of echovirus dermatomyositis and meningoencephalitis.

A previously described patient with X-linked agammaglobulinemia and growth hormone deficiency developed an echovirus-associated meningoencephalitis and dermatomyositis-like syndrome while being treated with intramuscular gamma globulin and human growth hormone. Initiation of high-dose intravenous gamma globulin resulted in resolution of the clinical symptoms and the patient has remained asymptomatic over the past 55 months. Lymphocyte phenotype analysis at the time of presentation with echovirus infection revealed an increase in CD2+, CD16+, HNK-1+ lymphocytes, a decrease in CD4+ T cells as well as absence of B cells. This elevation in the LGL/NK phenotype resolved with clinical improvement. In addition, there was evidence of lymphocyte activation following the development of echovirus infection (increase in HLA-DR expression and elevated serum IL-2 receptor levels) which resolved with clinical improvement. A muscle biopsy obtained during the period of the dermatomyositis-like syndrome demonstrated a CD8+ lymphocytic infiltrate very similar to the observations in classical dermatomyositis. Taken together, these findings suggest that growth hormone therapy in this patient failed to alter the humoral immunodeficiency. In addition, serum IL-2 receptor levels and lymphocyte phenotyping may be useful adjuncts for monitoring echovirus disease in immunodeficient patients.

Release of soluble interleukin-2 receptors (Tac peptide) in vivo during human immune responses to tuberculin.

Cutaneous levels of soluble interleukin-2 receptor (Tac peptide) have been measured in tuberculin responses in 13 human volunteers by assaying the fluid present in suction-induced blisters at various times after injection of standard purified protein derivative of tuberculin (PPD). Low levels of Tac peptide were found in blisters without prior injection of PPD and in PPD-negative individuals, and maximal levels of Tac peptide were correlated with increased induration at 48 hr (r = 0.69, P = 0.04) in PPD-positive subjects. This is the first report of measurement of Tac peptide in vivo in a defined immune response in man, and may offer a new approach to the study of human immune function in vivo.