Use of Chest Computed Tomography for Blunt Pediatric Chest Trauma: Does It Change Clinical Course?

INTRODUCTION: Given the concern for radiation-induced malignancy in children and the fact that risk of severe chest injury in children is low, the risk/benefit ratio must be considered in each child when ordering a computed tomography (CT) scan after blunt chest trauma. METHODS: The study included pediatric blunt trauma patients (age, <15 years) with chest radiograph (CR) before chest CT on admission to our adult and pediatric level I trauma center. Surgeons were asked to view the blinded images and reads and indicate if they felt CT was warranted based on CR findings, if their clinical management change based on additional findings on chest CT, and how they might change management. RESULTS: Of the 127 patients identified, 64.6% had no discrepancy between their initial CR and chest CT and 35.4% of the children's imaging contained a discrepancy. The majority of the pediatric and general trauma surgeons felt CT was indicated in 6 of 45 patients based on CR. In 87% of patients with a discrepancy in findings on CR and CT, the majority of surgeons agreed that their management would not change based on the additional information. In the 6 patients in which the CT was considered indicated, 4 of the 6 would have triggered a management change. CONCLUSIONS: Our study suggests that chest CT scans frequently serve as confirmatory diagnostic tools and in the pediatric blunt chest trauma patient and can be withheld in many cases without hindering the management of an injured child.

Peritoneal dialysis catheter placement, outcomes and complications.

PURPOSE: Peritoneal dialysis (PD) is a commonly used method for renal support in pediatric patients and can be associated with the risk of post-surgical complications. We evaluated method of placement of PD catheters with regard to post-surgical complications. METHODS: PD catheters placed at two institutions between 2005 and 2017 were reviewed. Complication rates were evaluated based on method of placement, delayed usage, omentectomy, and patient age using Fisher's exact test, two-sided, with significance set at 0.05. Factors influencing complication were evaluated with multivariate logistic regression and Kaplan-Meier survival analysis. RESULTS: There were 130 patients with 157 catheters placed, ranging in age from 1 day to 23 years. There was no significant difference in complication rate by method of placement or delayed usage. Infants were significantly more likely to experience leakage (21% vs 8%, p 0.036) and hernias (15% vs 5%, p 0.030). Patients that underwent an omentectomy were less likely to require a catheter replacement (7% vs 27%, p 0.004), and the catheters had a significantly higher survival rate (p 0.009). We found that laparoscopic intervention resulted in catheter salvage. Lateral exit sites may be a risk factor for catheter migration in some patients. CONCLUSIONS: Omentectomy is associated with longer PD catheter survival. Laparoscopic salvage of dysfunctional catheters may be a valuable adjunct in management.

Antibacterial synergy of glycerol monolaurate and aminoglycosides in Staphylococcus aureus biofilms.

Glycerol monolaurate (GML) is a natural surfactant with antimicrobial properties. At ∼0.3 mM, both GML and its component lauric acid were bactericidal for antibiotic-resistant Staphylococcus aureus biofilms. With the use of MICs of antibiotics obtained from planktonic cells, GML and lauric acid acted synergistically with gentamicin and streptomycin, but not ampicillin or vancomycin, to eliminate detectable viable biofilm bacteria. Images of GML-treated biofilms suggested that GML may facilitate antibiotic interaction with matrix-embedded bacteria.

Anoxia inhibits biofilm development and modulates antibiotic activity.

BACKGROUND: Many infections involve bacterial biofilms that are notoriously antibiotic resistant. Unfortunately, the mechanism for this resistance is unclear. We tested the effect of oxygen concentration on development of Staphylococcus aureus biofilms, and on the ability of gentamicin and vancomycin to inhibit biofilm development. MATERIALS AND METHODS: To mimic catheter-associated biofilms, silastic coupons were inoculated with 10(7)S aureus and incubated either aerobically (∼21% O2) or anaerobically (10% CO2, 5% H2, 85% N2) for 16 h at 37°C with varying concentrations of gentamicin and vancomycin. Viable colony-forming units were quantified from sonicated biofilms, and the crystal violet assay quantified biofilm biomass. Metabolomic profiles probed biochemical differences between aerobic and anaerobic biofilms. RESULTS: Control biofilms (no antibiotic) cultivated aerobically contained 8.1-8.6 log10S aureus. Anaerobiasis inhibited biofilm development, quantified by viable bacterial numbers and biomass (P < 0.05). Bactericidal concentrations of gentamicin inhibited biofilm development in normoxia but not anoxia, likely because bacterial uptake of gentamicin is oxygen dependent. The inhibitory effect of vancomycin was more uniform aerobically and anaerobically, although at high bactericidal concentrations, vancomycin effectiveness was decreased under anoxia. There were notable differences in the metabolomic profiles of biofilms cultivated under normoxia versus anoxia. CONCLUSIONS: Compared with aerobic incubation, anaerobiasis resulted in decreased biofilm development, and metabolomics is a promising tool to identify key compounds involved in biofilm formation. The effectiveness of a specific antibiotic depended on its mode of action, as well as on the oxygen concentration in the environment.

Interplay of antibiotics and bacterial inoculum on suture-associated biofilms.

BACKGROUND: Biofilms are often antibiotic resistant, and it is unclear if prophylactic antibiotics can effectively prevent biofilm formation. Experiments were designed to test the ability of high (bactericidal) concentrations of ampicillin (AMP), vancomycin (VAN), and oxacillin (OXA) to prevent formation of suture-associated biofilms initiated with low (10(4)) and high (10(7)) numbers of Staphylococcus aureus. MATERIALS AND METHODS: S. aureus biofilms were cultivated overnight on silk suture incubated in biofilm growth medium supplemented with bactericidal concentrations of AMP, VAN, or OXA. Standard microbiological methods were used to quantify total numbers of viable suture-associated S. aureus. Crystal violet staining followed by spectroscopy was used to quantify biofilm biomass, which includes bacterial cells plus matrix components. To observe the effects of antibiotics on the microscopic appearance of biofilm formation, biofilms were cultivated on glass slides, then stained with fluorescent dyes, and observed by confocal microscopy. RESULTS: In the presence of a relatively low inoculum (10(4)) of S. aureus cells, bactericidal concentrations of AMP, VAN, or OXA were effective in preventing development of suture-associated biofilms. However, similar concentrations of these antibiotics were typically ineffective in preventing biofilm development on sutures inoculated with 10(7)S. aureus, a concentration relevant to contaminated skin. Confocal microscopy confirmed that bactericidal concentrations of AMP, VAN, or OXA inhibited, but did not prevent, development of S. aureus biofilms. CONCLUSION: Bactericidal concentrations of AMP, VAN, or OXA inhibited formation of suture-associated biofilms initiated with low numbers (10(4)), but not high numbers (10(7)), of S. aureus cells.

Analysis of pediatric sternal fractures using the Kid's Inpatient Database (KID).

PURPOSE: This study aims to determine if sternal fracture is a predictor of discharge requiring additional care and mortality. METHODS: Blunt pediatric trauma admissions (<18 years) in the Kid's Inpatient Database (2016) were included in analysis. Weighted incidence of sternal fracture was calculated and adjusted for using survey weight, sampling clusters, and stratum. Regression analysis was used to identify factors associated with poor outcomes. RESULTS: Annual incidence of sternal fracture in the pediatric blunt trauma population was 0.43 per 100,000. Of 50,076 patients identified, 236 had sternal fractures. The sternal fracture patients were older (median 16 vs 10 years, P < 0.001) and motor vehicle accident was more frequently the mechanism of injury (78% vs 24%, P < 0.001). Common injuries associated with sternal fracture included clavicle fracture (43%), abdominal organ injury (28%), spinal fracture (47%), lung injury (65%), and rib fracture (47%).  Sternal fracture patients were more frequently discharged to receive additional care (22% vs 5%, P < 0.001) and to die of their injuries (3.8% vs 0.9%, P < 0.001). When adjusting for other factors associated with poor outcomes, sternal fracture was not an independent predictor of mortality or discharge to care. CONCLUSIONS: Sternal fracture is a severe injury in the pediatric population, but it is not independently associated with need for a higher level of care after discharge or mortality.

Gentamicin promotes Staphylococcus aureus biofilms on silk suture.

BACKGROUND: Communities of bacteria, termed biofilms, develop on biotic and abiotic surfaces, including medical devices and surgical suture. Biofilm-associated bacteria are typically recalcitrant to antibiotic therapy, and the effects of antibiotics on microbial biofilms are not clearly understood. There is emerging evidence that under specific conditions, aminoglycosides may actually promote biofilm development. Experiments were designed to study the effects of gentamicin on suture-associated Staphylococcus aureus biofilms. MATERIALS AND METHODS: S. aureus biofilms were formed after 24 h incubation of bacteria with silk suture. Susceptibility of planktonic S. aureus (from broth culture) to gentamicin was compared with the susceptibility of cells from mechanically dispersed S. aureus biofilms. Subinhibitory and inhibitory concentrations of gentamicin were subsequently incubated with intact suture-associated biofilms. S. aureus viability and metabolic capacity were assessed, and biofilm biomass was quantified with crystal violet (binds negatively charged surface molecules) and with the nucleic acid stain Syto 9. Scanning electron microscopy was used to assess the effect of gentamicin on the ultrastructure of suture-associated S. aureus biofilms. RESULTS: Planktonic cells and S. aureus cells from mechanically dispersed biofilms had similar susceptibility to gentamicin. However, after incubation of high concentrations of gentamicin with intact biofilms, high numbers of S. aureus remained both viable and metabolically active; biofilm biomass was increased and biofilm ultrastructure showed staphylococcal cells within copious amounts of extracellular material. CONCLUSION: Gentamicin does not effectively kill S. aureus within intact suture-associated biofilms, and gentamicin also promotes the biomass of S. aureus biofilms.

Role of Staphylococcus aureus protein A in adherence to silastic catheters.

BACKGROUND: Communities of bacteria, termed biofilms, frequently develop on central venous catheters, and bacterial contamination of central venous catheters is the most common cause of nosocomial bloodstream infections. Little is known about the initial events in bacterial adherence to the catheter surface, and experiments were designed to clarify the role of staphylococcal protein A, serum, and immunoglobulin in adherence of Staphylococcus aureus to silastic catheters. We hypothesized that S. aureus protein A in the presence of serum and immunoglobulin would alter S. aureus adherence to silastic catheters. MATERIALS AND METHODS: Three strains of S. aureus with varying expression of staphylococcal protein A were incubated 15 min at room temperature with silastic catheters, and bacterial adherence to the catheter surface was quantified. In addition, the effects of serum, albumin, and purified IgG on bacterial adherence were assessed. RESULTS: Both serum and albumin had an inhibitory effect on S. aureus adherence to the catheter surface, and protein A expression did not appreciably modulate these effects. Purified serum IgG also inhibited S. aureus adherence, with IgG having a greater inhibitory effect on the adherence of an S. aureus strain deficient in protein A compared with an S. aureus strain expressing high levels of protein A. CONCLUSION: S. aureus adherence to silastic catheters was inhibited by whole serum, albumin, and purified IgG. Expression of staphylococcal protein A interfered with IgG mediated inhibition of bacterial binding to the catheter surface. Protein A altered S. aureus adherence to silastic catheters in the presence of immunoglobulin, but not in the presence of serum or albumin.

Selected factors affecting Staphylococcus aureus within silastic catheters.

BACKGROUND: Catheter-related infections are frequent complications in hospitalized patients, and Staphylococcus aureus is a frequent etiologic agent. Little is known about factors that contribute to the growth and viability of S. aureus within contaminated catheters. MATERIALS AND METHODS: In vitro experiments assessed the ability of S. aureus to adhere to silastic catheter tubing. The effects of heparin, serum, and calcium on initial bacterial adherence were also assessed. Additional experiments quantified the effect of ethanol locking on S. aureus viability within catheter-associated biofilms produced after 48 to 72 h incubation of S. aureus with catheters under conditions of nutrient flow. Scanning electron microscopy visualized the effect of ethanol locking on the morphology of bacterial vegetations adherent to the catheter wall. RESULTS: S. aureus readily adhered (in a dose dependent manner) to silastic catheters incubated with bacteria for 15 min, and adherence was not affected by calcium or heparin (even though heparin adhered to the silastic tubing and S. aureus is known to express heparin-binding proteins). S. aureus adherence was inhibited by serum but not albumin. Ethanol locking (5 min to 24 h) of catheters containing mature 48 to 72 h S. aureus biofilms resulted in no detectable bacterial viability, although scanning electron microscopy revealed similar bacterial vegetations adherent to control and ethanol-treated catheters. CONCLUSION: S. aureus adherence to silastic catheters was inhibited by serum, but the active inhibitory component was not albumin. Ethanol locking efficiently sterilized S. aureus contaminated catheters, although nonviable bacterial vegetations remained on the ethanol-treated catheters.

Echocardiographic assessment of ductal anatomy in premature infants-lessons for device design.

OBJECTIVE: Echocardiographic analysis of patent ductus arteriosus (PDA), proximal left main pulmonary artery (LPA) and descending thoracic aorta (Ao) dimensions in preterm infants who undergo surgical ligation of the PDA. A discussion for percutaneous ductal occlusion in preterm infants. METHODS: Echocardiographic analysis of the LPA diameter, PDA diameter, PDA length, and descending thoracic aorta diameter in 55 preterm infants who underwent surgical ligation of the PDA from 2004 to 2008. Patients were stratified by weight into four groups: those less than 750 g, 751-1,000 g, 1,001-1,250 g, and those greater than 1,250 g. Mean and standard deviation for each structure dimension was calculated in each weight group. Structural dimensions were compared between groups using ANOVA for multiple comparisions. RESULTS: The mean patient weight was 1,018 g (560-2,400 g). The mean ductal length was 4.1 mm (2.5-5.3 mm). The mean ductal diameter was 2.2 mm (1.5-3.6 mm). The mean LPA diameter was 3 mm (1.5-4.5 mm). The mean aortic diameter was 4.3 mm (2.7-7.8 mm). The alpha value for between weight groups for PDA length was 0.21, PDA diameter 0.16, LPA diameter 0.39, and aortic diameter 0.1. DISCUSSION: No statistical significance was seen when comparing structure dimension by weight. This suggests uniform structural dimensions across a broad weight distribution in this patient population. To date, there has been no attempt to standardize dimensions of these vascular structures. The information gathered in this study may be useful in developing an implantable device for ductal occlusion in preterm infants. (ECHOCARDIOGRAPHY 2010;27:575-579).

Not every bulb is a rose: a functional comparison of bulb suction devices.

BACKGROUND: Not all closed drainage suction bulbs are equivalent, and there may be a discrepancy between purported and observed clinical efficacy. We evaluated four popular bulb suction apparati to directly compare their maximum attainable suction, maximum volume collected, and negative pressure maintained relative to volume collected. METHODS: Employing a developed-calibrated digital collection system, the relative function of the Surgidyne 100cc (SD100), Jackson-Pratt 100cc (JP100), Jackson-Pratt 400cc (JP400), and HemoVac 400cc (HV400) drains were compared. For these analyses, three separate drains of each type (JP100 utilized 6 drains) were tested in triplicate (alpha =0.05). RESULTS: The SD100 bulbs achieved the greatest negative pressure (-167.4 mmHg) while the HV400s the least (-80.5mm Hg). Only the SD100s pulled at or above purported volume. All other types obtained volumes significantly less than their described volumes: for each bulb type, the obtained volumes were statistically different. Of note, 66.7% (4 of 6) of JP100 bulbs collected only half the purported volume. CONCLUSIONS: The use of the SD100 bulb demonstrated superior maximum attainable suction, maintained suction to a higher volume; they were the only bulbs tested that collected volumes at or above those purported. The HV400 bulbs demonstrated the lowest suction and volume collected. Nevertheless, when used clinically, all such drain bulbs must be emptied long before achieving maximum volume to maintain reliable suction.

Escherichia coli and TNF-alpha modulate macrophage phagocytosis of Candida glabrata.

BACKGROUND: The incidence of systemic nonalbicans Candida (especially C. glabrata) infections is increasing dramatically in intensive care units, but relatively little is known about the pathogenesis or host defenses associated with these life threatening infections. MATERIALS AND METHODS: The course of systemic C. glabrata infection was assessed as the fungal burden in the kidneys and livers of mice sacrificed 1, 8, and 15 d after intravenous C. glabrata. Sixteen hours before each sacrifice, half of the mice were injected intraperitoneally with intact viable or nonviable E. coli cells, or with E. coli lipopolysaccharide (LPS), or with tumor necrosis factor (TNF)-alpha. To clarify the effect of LPS and TNF-alpha on phagocytosis, resident (unstimulated) mouse peritoneal macrophages were harvested, cultivated ex vivo, and some cultures were treated with LPS or TNF-alpha prior to 30 min incubation with C. glabrata. RESULTS: Compared with mice injected with vehicle, each agent (intact E. coli cells or E. coli LPS or TNF-alpha) was consistently associated with decreased numbers of tissue C. glabrata, and some of these decreases were significant (P < 0.05). Compared with untreated macrophages, phagocytosis of C. glabrata was increased with LPS-treated macrophages (P < 0.01), and phagocytosis was also increased in the presence of TNF-alpha (P < 0.01). CONCLUSION: E. coli LPS and TNF-alpha may participate in host defense against C. glabrata by a mechanism involving increased macrophage phagocytosis, suggesting that stimulation of inflammatory cytokines may facilitate host clearance of C. glabrata.

Modified approach to laparoscopic gastrostomy tube placement minimizes complications.

INTRODUCTION: Complications from previously published techniques for laparoscopic gastrostomy tube placement include skin pressure necrosis and extraluminal migration. We developed a modified technique utilizing subcutaneous stay-sutures in order to minimize such complications. This study aimed to identify, quantify, and characterize complications of the modified procedure. MATERIALS AND METHODS: Charts were reviewed of all pediatric patients undergoing laparoscopic gastrostomy tube placement over 79 months. Complications requiring reoperation, readmission, or outpatient treatment were identified and classified as major or minor. RESULTS: Laparoscopic gastrostomy tubes were placed via modified procedure in 82 patients. Two (2.44%) high-risk patients with significant comorbidities were readmitted for wound infections, two (2.44%) received outpatient antibiotics for cellulitis, and three (3.66%) developed stitch abscesses which resolved with local care. None of the patients had initial intraperitoneal placement, intraperitoneal location upon tube replacement, extraluminal migration, tube-related pressure necrosis, or procedure-related death. CONCLUSION: Subcutaneous placement of absorbable stay-sutures for laparoscopic gastrostomy tubes offers significant benefits. We eliminated complications associated with presence of external sutures, as well as those associated with early suture removal. This modified technique avoids additional visits for suture removal, avoids pressure necrosis from external stay-sutures, and provides improved adherence of stomach to abdominal wall, thereby preventing extraluminal migration and intraperitoneal tube replacement.

A review of racial/ethnic disparities in pediatric trauma care, treatment, and outcomes.

Health disparities are an increasingly researched topic in the United States. Evidence of disparities found across the spectrum of health care includes pediatric patients. The purpose of this review is to comprehensively summarize disparities among pediatric trauma patients, evaluating both emergency department and hospital treatment and outcomes. Multiple studies describe disparities in a variety of areas of trauma care including emergency department, radiology, surgery, abuse evaluation, and discharge rehabilitation. More concerning, multiple studies report disparities in length of stay, disability, recidivism, and mortality. This review also highlights several gaps in disparity research including specialty care, inclusion of all racial/ethnic groups, and geographic differences. Few of the reviewed studies described disparity interventions; however, research regarding abuse evaluations showed that care guidelines diminished disparity. Trauma care, a routinized patient service, is subject to existing care guidelines and quality improvement programs, and may be the ideal health care setting for disparity intervention. LEVEL OF EVIDENCE: Study type review, level V.

Standardized irrigation technique reduces intraabdominal abscess after appendectomy.

PURPOSE: The utility of irrigation at the time of appendectomy for acute appendicitis has been debated, with recent studies showing no benefit to irrigation. In our practice, two techniques have been used; one in which irrigation was at the discretion of the surgeon, and one in which irrigation was standardized. The standardized irrigation technique involved large volume (3-12 l) irrigation in small, focused, directed aliquots to achieve optimal dilution. We sought to retrospectively assess whether the standardized large volume irrigation technique was associated with measurably reduced intraabdominal infection. We hypothesized that there would be no difference in intraabdominal infection rate. METHODS: Medical records for cases of appendectomies performed for acute appendicitis, years 2007 through 2017, were reviewed (n = 432). Rate of subsequent abdominal infection was compared between patients who underwent the standardized large volume irrigation technique compared to those who did not using Fisher's exact test; p < 0.05 was considered significant. RESULTS: For patients that underwent the standardized large volume irrigation technique there were no (0/140) subsequent abdominal infections within the study period, compared with a rate of 6.2% (18/292) for all other patients (p value 0.001). Among cases that had a perforated appendix (n = 105), the rates were 0% (0/31) compared to 18.9% (14/74; p value 0.009). CONCLUSIONS: Utilization of a standardized large volume irrigation technique with the objective of serial dilution is associated with a significantly lower rate of subsequent abdominal infection, even among cases with a perforated appendix. Prospective studies are needed to evaluate this technique. LEVEL OF EVIDENCE: Level III. TYPE OF STUDY: Treatment study.

Combined laparoscopic-fluoroscopic technique for primary gastrojejunostomy button tube placement.

BACKGROUND: Gastrojejunostomy (GJ) tubes are frequently used to provide pediatric enteral nutritional support for pediatric patients. Various placement methods have been described, each with attendant advantages and disadvantages. DESCRIPTION OF THE OPERATIVE TECHNIQUE: We present a technique for primary laparoscopic/fluoroscopic GJ button tube placement designed to avoid delay in placement of the jejunal limb, and difficulties associated with endoscopic-assisted and primary fluoroscopic placement. RESULTS: There were 52 gastrojejunostomy button tubes placed via this technique in patients ranging from 3.8 to 90.3 kg in weight. Three postoperative complications were identified; one bowel perforation on postoperative day two, and two tube dislodgements within 30 days. CONCLUSION: The described technique was uniformly effective and was associated with a low complication rate (5.8%).

Radial umbilical dermatofasciolysis to invert the skin following umbilical herniorrhaphy.

BACKGROUND: Umbilical hernia is a common congenital anomaly, and can result in the appearance of a protuberant umbilicus. In select cases, inversion of the umbilical skin can be impaired by the presence of thickened dermis or fascial remnants of the umbilical stalk. DESCRIPTION OF OPERATIVE TECHNIQUE: After umbilical herniorrhaphy, the skin is everted over the left index finger and radial partial thickness incisions in the fascia and dermis of the undersurface of the umbilicus. The umbilical skin is then inverted and secured to the fascia. CONCLUSION: This operative technique can allow complete inversion of the umbilical skin creating an aesthetically appealing umbilical hernia repair.

Escherichia coli modulates extraintestinal spread of Staphylococcus aureus.

Staphylococcus aureus remains one of the most frequent causes of life-threatening systemic infection in surgical and trauma patients. It is understood that S. aureus colonization predisposes to complicating infection, but extraintestinal dissemination of S. aureus from the intestinal lumen to the draining mesenteric lymph nodes has not been systematically studied. After oral inoculation with high numbers of S. aureus, otherwise normal mice had low levels of cecal S. aureus (6.7 log10/g) and the incidence of extraintestinal dissemination was 30%. As expected, parenteral Escherichia coli lipopolysaccharide (LPS) was associated with increased numbers of cecal S. aureus, but the incidence of translocation remained unchanged. Purified LPS had no effect on S. aureus internalization by cultured HT-29 enterocytes and no effect on S. aureus transmigration through confluent enterocytes. To begin to clarify the effect of alterations in cecal bacteria on S. aureus translocation, mice were orally inoculated with E. coli and S. aureus. Compared with mice inoculated with S. aureus alone, these mice had increased numbers of cecal E. coli and S. aureus, and the incidence of S. aureus translocation nearly doubled from 46% to 88%. Experiments with HT-29 enterocytes indicated that viable E. coli had no effect on S. aureus internalization, but viable E. coli was at least 40 times more potent in inducing S. aureus transmigration across confluent enterocytes compared with a corresponding amount of purified LPS. Thus, S. aureus disseminated from the intestinal tract of normal mice by a mechanism that could involve paracellular migration across the intestinal epithelial barrier.

Ability of the heparan sulfate proteoglycan syndecan-1 to participate in bacterial translocation across the intestinal epithelial barrier.

Although hundreds of microbial species reside in the human intestinal tract, comparatively few (e.g., Escherichia coli and other enterobacteria, Enterococcus faecalis, etc.) are typically associated with systemic infection in postsurgical, shock, and trauma patients. Syndecan-1 is the predominant cell surface heparan sulfate proteoglycan expressed on epithelia, and there is substantial evidence that heparan sulfate participates in interactions of a variety of frankly pathogenic microbes with mammalian cells. To investigate the role of syndecan-1 in interactions of enteric flora with intestinal epithelium, bacteria that might use the enterocyte as a portal of entry for systemic infection (including E. faecalis, E. coli, and other enterobacteria, and several species of staphylococci and streptococci) were studied for their abilities to interact with syndecan-1. Streptococcus bovis, S. agalactiae, S. pyogenes, Staphylococcus aureus, and S. epidermidis showed increased adherence to ARH-77 cells transfected to express syndecan-1. Heparin, a heparan sulfate analog, inhibited internalization of S. bovis, S. agalactiae, S. pyogenes, and S. aureus by HT-29 enterocytes (prominent syndecan-1 expression), but not Caco-2 enterocytes (relatively low syndecan-1 expression). Data from experiments with Chinese hamster ovary cells with altered glycosaminoglycan expression indicated that heparan sulfate and chondroitin sulfate (glycosaminoglycans on the syndecan-1 ectodomain) participated in bacterial interactions with mammalian cells. Thus, although E. faecalis, E. coli, and other gram-negative enterobacteria did not appear to interact with syndecan-1, this heparan sulfate proteoglycan may mediate enterocyte interactions with some staphylococci and streptococci that are known to cause systemic infections in specific populations of high-risk, immunosuppressed, postsurgical, and trauma patients.

The Natural Surfactant Glycerol Monolaurate Significantly Reduces Development of Staphylococcus aureus and Enterococcus faecalis Biofilms.

BACKGROUND: Bacterial biofilms are involved in a large proportion of clinical infections, including device-related infections. Unfortunately, biofilm-associated bacteria are typically less susceptible to antibiotics, and infected devices must often be removed. On the basis of a recent observation that lipid-rich biofilm matrix material is present in early biofilm formation and may protect a population of bacteria from interacting with ordinarily diffusible small molecules, we hypothesized that surfactants may be useful in preventing biofilm development. METHODS: Experimental Staphylococcus aureus or Enterococcus faecalis biofilms were cultivated on surgical suture suspended in a growth medium supplemented with the natural surfactant glycerol monolaurate (GML) or with a component molecule, lauric acid. After 16 h incubation, the numbers of viable biofilm-associated bacteria were measured by standard microbiologic techniques and biofilm biomass was measured using the colorimetric crystal violet assay. RESULTS: Both GML and lauric acid were effective in inhibiting biofilm development as measured by decreased numbers of viable biofilm-associated bacteria as well as decreased biofilm biomass. Compared with lauric acid on a molar basis, GML represented a more effective inhibitor of biofilms formed by either S. aureus or E. faecalis. CONCLUSIONS: Because the natural surfactant GML inhibited biofilm development, resulting data were consistent with the hypothesis that lipids may play an important role in biofilm growth, implying that interfering with lipid formation may help control development of clinically relevant biofilms.