Pyoderma caused by Pseudomonas aeruginosa infection in dogs: 20 cases

In this report we describe the historical, clinical, histopathological and microbiological features, as well as treatments and clinical outcome, of pyoderma where Pseudomonas aeruginosa alone was isolated on bacterial culture from lesional skin. Twenty dogs were included in this retrospective study. Seven dogs without prior history of systemic or skin disease presented with acute deep pseudomonal pyoderma characterized by a sudden onset of dorsal truncal pain. Skin lesions in these dogs consisted of erythematous papules, haemorrhagic bullae, ulcers and haemorrhagic crusts confined to the dorsum. An excellent clinical response was achieved with 3-4 weeks of treatment with oral fluoroquinolones. Thirteen dogs with a more gradual onset of skin lesions associated with pseudomonal pyoderma had a history of prior skin, ear or systemic disease and had previously been treated with antibiotics and/or immunomodulatory drugs. Skin lesions in these dogs were variable and similar to those described for superficial and deep staphylococcal pyoderma. In this group, one dog was euthanized prior to commencement of treatment, two dogs were lost to follow up, and 9 had resolution of lesions following treatment with topical silver sulfadiazine (one dog), fluoroquinolones (six dogs) or cephalexin (two dogs) administered orally for 3 to 12 weeks. Rod-shaped bacteria were not always detected on cytology. Histopathology of dogs with deep pseudomonal pyoderma was characterized by severe perforating suppurative folliculitis and furunculosis.

Design and delivery of silver sulfadiazine from alginate microspheres-impregnated collagen scaffold

A reconstituted collagen scaffold impregnated with silver sulfadiazine (SSD) loaded alginate microspheres, capable of delivering the drug in a controlled manner has been developed. SSD-loaded alginate microspheres were prepared by modified water-in-oil emulsion technique through interfacial ionic gelation of alginate using CaCl2. The SSD-loaded microspheres were impregnated in pepsin-solubilized collagen, in situ, while inducing fibrillation and cast as thin scaffold. Morphological features of microspheres and microsphere-impregnated collagen were analyzed through SEM. Distribution homogeneity of impregnated microspheres, their in vitro behavior in (Dulbecco's modified minimal essential media) DMEM, and antibacterial efficiency against ATCC pathogens were determined. Initial drug load of 20% (w/w) with respect to alginate and 40% (v/v) of 2% alginate with respect to oil phase were found to produce microspheres of optimum drug entrapment (3%) and required size range (300-370 microm). In vitro drug release studies from the scaffold showed an initial burst release of 47.5% and a controlled release for 72 h with equilibrium concentration of 68.8%. SSD-loaded microspheres exhibited minimal inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) levels of 32 and 40.2 microg/mL to both K. pneumoniae and E. coli respectively. P. aeruginosa showed MIC and MBC levels of 44.8 and 51.2 microg/mL respectively, while Staphylococcus aureus exhibited MIC and MBC at the same concentration range (57.6 microg/mL). The collagen-based scaffold impregnated with SSD-loaded alginate microspheres can deliver SSD in a controlled fashion, can control infection for extended time period with lesser dressing frequencies, and will enable easier assessment of wound.

Efficacy of antiseptic-impregnated catheters on catheter colonization and catheter-related bloodstream infections in patients in an intensive care unit

This study was conducted to evaluate the impact of central venous catheters impregnated with chlorhexidine and silver sulphadiazine on the incidence of colonization and catheter-related bloodstream infection in critically ill patients. One hundred and thirty-three patients requiring central venous catheterization were chosen at random to receive either an antiseptic-impregnated triple-lumen catheter (N=64) or a standard triple-lumen catheter (N=69). The mean (SD) durations of catheterization for the antiseptic and standard catheters were 11.7 (5.8) days (median 10; range 3-29) and 8.9 (4.6) days (median 8.0; range 3-20), respectively (P=0.006). Fourteen (21.9%) of the antiseptic catheters and 14 (20.3%) of the standard catheters had been colonized at the time of removal (P=0.834). Four cases (6.3%) of catheter-related bloodstream infection were associated with antiseptic catheters and one case (1.4%) was associated with a standard catheter (P=0.195). The catheter colonization rates were 18.7/1000 catheter-days for the antiseptic catheter group and 22.6/1000 catheter-days for the standard catheter group (P=0.640). The catheter-related bloodstream infection rates were 5.3/1000 catheter-days for the antiseptic catheter group and 1.6/1000 catheter-days for the standard catheter group (P=0.452). In conclusion, our results indicate that the use of antiseptic-impregnated central venous catheters has no effect on the incidence of either catheter colonization or catheter-related bloodstream infection in critically ill patients.

Application of cerium nitrate–silver sulphadiazine allows for postponement of excision and grafting

Early excision and grafting cannot always be performed due to patient's medical status, and the lack of adequate donor sites. The use of cerium nitrate-silver sulphadiazine cream, which causes the formation of a leather-like eschar with excellent resistance to infection, is an alternative method. In order to postpone operations by using cerium nitrate-silver sulphadiazine, we compared the differences in contamination of the grafted areas between early and delayed excision. Eighteen patients underwent excision and grafting within 5 days post burn and nineteen patients were surgically treated after 5 days. Twelve months later the grafted areas were evaluated. Contamination of the grafted area occurred in 17 patients. No differences in contamination occurred between the early and delayed excision group, 8 versus 9. Also no differences in type of organism cultured and follow-up results were found between the early and delayed excision group. Cerium nitrate-silver sulphadiazine allows surgical treatment to be delayed without an increase of contamination of the grafted area and does not adversely affect the long-term outcome.

Central venous catheter colonization in critically ill patients: a prospective, randomized, controlled study comparing standard with two antiseptic-impregnated catheters

In this prospective, randomized, controlled, unblinded study, we compared colonization rates of a standard, unimpregnated central venous catheter (CVC) with rates for silver-coated and chlorhexidine-silversulfadiazine (CH-SS)-impregnated CVC. Patient characteristics, CVC insertion site, indwelling time, and colonization detected by semiquantitative and quantitative microbiologic techniques were documented. Two-hundred-seventy-five critically ill patients were included into the study protocol. One-hundred-sixty standard, 160 silver (S)-coated, and 165 externally impregnated CH-SS CVC were inserted. There was a significant difference in CVC colonization rates among study groups (P = 0.029). There was no difference in the colonization rate and the colonization per 1000 catheter days between standard and S-coated (P = 0.564; P = 0.24) or CH-SS-coated CVC (P= 0.795; P = 0.639). When comparing antiseptic CVC with each other, colonization rates were significantly less with CH-SS-impregnated than with S-coated CVC (16.9% versus 7.3%; P = 0.01; 18.2 versus 7.5 of 1000 catheter days; P = 0.003; relative risk, 0.43; 95% confidence interval, 0.21-0.85). Whereas standard and S-coated CVC were first colonized 2 and 3 days after insertion, respectively, CH-SS CVC were first colonized only after 7 days. In conclusion, antiseptic-impregnated CVC could not prevent catheter colonization when compared with standard polyurethane catheters in a critical care setting with infrequent catheter colonization rates and CVC left in place for >10 days.

Insuffisance rénale aiguë après application topique de sulfadiazine argentique

INTRODUCTION

Prolonged topical application of silver sulfadiazine cream can induce argyria and adverse effects of sulphonamides. We report a case of a woman with acute renal failure following repeated applications of topical silver sulfadiazine on pyoderma gangrenosum wounds.

CASE REPORT

A 61 year-old woman suffering from rheumatoid arthritis, Sjogren's syndrome and scleroderma was treated with corticosteroids (1 mg/kg/day) and topical application of silver sulfadiazine cream (200 g/day) for extensive pyoderma gangrenosum wounds on the legs. Three weeks later, the patient was transferred to intensive care because of pulmonary edema, oligoanuria and disrupted consciousness. Laboratory data revealed leukopenia (1100/mm(3)) with neutropenia and renal failure (serum creatinine 316 micromol/l). Proteinuria was moderate and ultrasonography of the kidneys was normal. Silver concentration in blood was 1818 nmol/l (N < 92 nmol/l) and 1381 nmol/l (N < 9 nmol/l) in urine. Sulfadiazine concentration in blood was undetectable. All the signs regressed after withdrawal of silver sulfadiazine and after several sessions of hemodialysis.

DISCUSSION

Various causes of renal failure are discussed in our patient. However, direct silver-induced renal toxicity is the most likely and is confirmed by the high concentration of silver in blood and urine and the improvement on withdrawal of the topical cream, without modification in the oral treatment. The absence of red corpuscles and crystals in the urine and undetectable concentrations of sulfadiazine in blood are not in favor of sulphonamide renal toxicity. Furthermore, the autoimmune diseases of our patient were well-controlled. Leukopenia could be secondary to silver sulfadiazine medullar toxicity. This observation confirms that this topical cream should not be used for long periods on extensive wounds.

Effect of a second-generation venous catheter impregnated with chlorhexidine and silver sulfadiazine on central catheter-related infections: a randomized, controlled trial

BACKGROUND

Central venous catheter-related infections are a significant medical problem. Improved preventive measures are needed.

OBJECTIVE

To ascertain 1) effectiveness of a second-generation antiseptic-coated catheter in the prevention of microbial colonization and infection; 2) safety and tolerability of this device; 3) microbiology of infected catheters; and 4) propensity for the development of antiseptic resistance.

DESIGN

Multicenter, randomized, double-blind, controlled trial.

SETTING

9 university-affiliated medical centers.

PATIENTS

780 patients in intensive care units who required central venous catheterization.

INTERVENTION

Patients received either a standard catheter or a catheter coated with chlorhexidine and silver sulfadiazine.

MEASUREMENTS

The authors assessed catheter colonization and catheter-related infection, characterized microbes by molecular typing, and determined their susceptibility to antiseptics. Patient tolerance of the catheter was monitored.

RESULTS

Patients with the 2 types of catheters had similar demographic features, clinical interventions, laboratory values, and risk factors for infection. Antiseptic catheters were less likely to be colonized at the time of removal compared with control catheters (13.3 vs. 24.1 colonized catheters per 1000 catheter-days; P < 0.01). The center-stratified Cox regression hazard ratio for colonization controlling for sampling design and potentially confounding variables was 0.45 (95% CI, 0.25 to 0.78). The rate of definitive catheter-related bloodstream infection was 1.24 per 1000 catheter-days (CI, 0.26 to 3.62 per 1000 catheter-days) for the control group versus 0.42 per 1000 catheter-days (CI, 0.01 to 2.34 per 1000 catheter-days) for the antiseptic catheter group (P = 0.6). Coagulase-negative staphylococci and other gram-positive organisms were the most frequent microbes to colonize catheters. Noninfectious adverse events were similar in both groups. Antiseptic susceptibility was similar for microbes recovered from either group.

LIMITATIONS

The antiseptic catheter was not compared with an antibiotic-coated catheter, and no conclusion can be made regarding its effect on bloodstream infection.

CONCLUSIONS

The second-generation chlorhexidine-silver sulfadiazine catheter is well tolerated. Antiseptic coating appears to reduce microbial colonization of the catheter compared with an uncoated catheter.

Octylcyanoacrylate for the treatment of small, superficial, partial-thickness burns: a pilot study

BACKGROUND

Octylcyanoacrylate (OCA) is a tissue adhesive used to close wounds and to treat minor abrasions.

OBJECTIVE

To explore the use of OCA in patients with superficial, partial-thickness burns.

METHODS

A prospective, noncomparative, pilot study was conducted in an emergency department (ED) and burn center. Consecutive patients with early (< 6 hours), small (< 5% total body surface area [TBSA]), superficial, partial-thickness burns were enrolled. Burns were cleaned and any nonadherent necrotic epidermis was removed. Tense blisters were aseptically aspirated. Burns were then covered with a liquid OCA that was applied with a sponge brush. Pain of cleansing and OCA application was recorded, and physicians assessed ease of application. Burns were evaluated every one to two days until complete epithelialization for the presence of infection and exudation, and the OCA was reapplied as necessary. Main outcomes measured were the need for additional topical therapy, pain and ease of application, patient comfort, and satisfaction.

RESULTS

Ten patients were enrolled. Mean patient age (+/- standard deviation [SD]) was 23 (+/- 16) years, four were female, and nine were white. Burns were located on the hands (5), forearms (3), ankle (1), and back (1). Etiologies included contact (4), flame (4), and scald (2) burns. Mean (+/- SD) burn size was 71 (+/- 72) cm(2). Blisters were present on admission in all patients and remained intact in five. Application of OCA was very easy in all patients; it immediately relieved pain in four patients and had no effect in three patients, while three patients complained of a brief increase in pain on OCA application. Exudation was present in four of ten patients within one to two days, all of whom had ruptured blisters at initial presentation. OCA was reapplied in two of these patients, and two patients were changed to silver sulfadiazine due to excessive exudation. The OCA was removed in one patient due to accumulation of exudate. There was no infection, and all burns were epithelialized within five to ten days.

CONCLUSIONS

The results of this pilot study suggest that OCA may be useful for some, but not all, small, superficial, partial-thickness burns. Further studies may help clarify the indications and contraindications to proper usage of OCA in small, superficial burns.

Comparison of Silver-Coated Dressing (Acticoat???), Chlorhexidine Acetate 0.5% (Bactigrass??), and Silver Sulfadiazine 1% (Silverdin??) for Topical Antibacterial Effect in Pseudomonas Aeruginosa-Contaminated, Full-Skin Thickness Burn Wounds in Rats

Acticoat (Smith and Nephew, Istanbul, Turkey), chlorhexidine acetate 0.5%, and silver sulfadiazine 1% were compared to assess the antibacterial effect of their application on experimental burn wounds in contaminated with Pseudomonas aeruginosa in rats. All treatment modalities were effective against P. aeruginosa because there were significant differences between treatment groups and control groups. The mean eschar concentrations did not differ significantly between Acticoat and chlorhexidine acetate groups, but there were significant differences between the silver sulfadiazine group and the other treatment groups, indicating that silver sulfadiazine significantly eliminated P. aeruginosa more effectively in the tissues than did the other two agents. All treatment modalities were sufficient to prevent the P. aeruginosa from invading to the muscle and from causing systemic infection. In conclusion, silver sulfadiazine is the most effective agent in the treatment of the P. aeruginosa-contaminated burn wounds; Acticoat can be considered as a treatment choice because of its peculiar ability of limiting the frequency of replacing wound dressings.

Second-degree burns: a comparative, multicenter, randomized trial of hyaluronic acid plus silver sulfadiazine vs. silver sulfadiazine alone

AIMS

This multicenter, multinational, randomized, double-blind, controlled, parallel-group study, was designed to assess the efficacy and safety of a fixed combination topical medicinal product, containing 0.2% hyaluronic acid and 1% silver sulfadiazine (HA-SSD) (Connettivina Plus cream) versus 1% silver sulfadiazine cream alone (SSD), in the treatment of second-degree burns.

METHODS

111 adult patients (age 18-75 years) of both sexes, with IIa-degree (superficial) and IIb-degree (deep dermal) burns, were randomized to receive HA-SSD or SSD. Treatments (approximately 5 g/100 cm2) were applied once a day until the wounds healed, but for no longer than 4 weeks. Burns had to have occurred within 48 hours from the start of treatment, be caused by thermal injury, and be confined to the trunk and/or upper and lower extremities.

RESULTS

Results showed that both the fixed combination HA-SSD, and SSD alone, were effective and well tolerated topical agents for the treatment of second-degree burns. All burns were healed except in one patient treated with SSD. It was also observed that the fixed combination HA-SSD caused a significantly more rapid re-epithelialization of burns, i.e. a shorter time to healing, than SSD alone. The difference recorded--4.5 days--was statistically significant (p = 0.0073).

CONCLUSION

The observed shorter time to healing caused by the fixed combination is clinically relevant and further demonstrates the wound healing activity of HA.

A silver coated dressing reduces the incidence of early burn wound cellulitis and associated costs of inpatient treatment: Comparative patient care audits

In 2000 and 2002, the Royal Perth Hospital (RPH) Burn Unit, Western Australia, conducted two 'before and after' patient care audits comparing the effectiveness and cost of Silvazine (silver sulphadiazine and chlorhexidine digluconate cream) and Acticoat, a new dressing product for in-patient treatment of early burn wounds. The main outcome variables were: burn wound cellulitis, antibiotic use and cost of treatment. Two patient care audits and a comparative sample were used. The two regimes audited were, 'standard treatment' of twice daily showers or washes with 4% chlorhexidine soap and Silvazine cream as a topical dressing (2000, n=51), compared with the 'new treatment' of daily showers of the burn wound with 4% chlorhexidine soap and the application of an Acticoat dressing (2002, n=19). In 2002, costs were also examined using a sample of matched pairs (n=8) of current and previous patients. The main findings were: when using Acticoat the incidence of infection and antibiotic use fell from 55% (28/51) and 57% (29/51) in 2000 to 10.5% (2/19) and 5.2% (1/19) in 2002. The total costs (excluding antibiotics, staffing and surgery) for those treated with Silvazine were US$ 109,357 and those treated with Acticoat were US$ 78,907, demonstrating a saving of US$ 30,450 with the new treatment. The average length of stay (LOS) in hospital was 17.25 days for the Silvazine group and 12.5 days for the Acticoat group-a difference of 4.75 days. These audits demonstrate that Acticoat results in a reduced incidence of burn wound cellulitis, antibiotic use and overall cost compared to Silvazine in the treatment of early burn wounds.

A Prospective, Randomized Trial of Acticoat Versus Silver Sulfadiazine in the Treatment of Partial-Thickness Burns: Which Method Is Less Painful?

Despite recent improvements in analgesia, pain control during dressing changes continues to be a major challenge in patients with burns. We investigated two different dressing modalities to compare how much pain the patient experienced during and after the dressing change. Patients with partial-thickness burns that required only topical wound care were assigned randomly to treatment with Acticoat (Smith and Nephew USA, Largo, FL) or silver sulfadiazine (AgSD). The outcome variable was pain during wound care, which was measured using visual analog pain scores. The mean visual analog pain scores for the wounds treated with Acticoat or AgSD wounds were 3.2 and 7.9, respectively (P < .0001; paired Student's t-test). In 41 of the 47 paired pain score observations, the pain in the wound treated with AgSD was perceived as greater than in the wound treated with Acticoat. Burn wound care with Acticoat is less painful than burn wound care with AgSD in patients with selected partial-thickness burns.

IPM/DOSS/water Microemulsions as Reactors for Silver Sulfadiazine Nanocrystal Synthesis

The first goal of this work was the preparation of a water-in-oil microemulsion from components generally regarded as safe for use in humans. Stable formulations without need of a co-surfactant were prepared from isopropyl myristate (IPM), dioctyl sodium sulfosuccinate (DOSS), and water. A ternary phase diagram was prepared for the IPM/DOSS/water system. The IPM/DOSS/water microemulsions were characterized by conductivity and dynamic laser light scattering (DLS). The results obtained from conductivity experiments indicate conductivity values of less than 1 muS/cm and were consistent with the formation of w/o microemulsions. The DLS results showed that the emulsified water droplets had an average diameter range of 9.2 to 19.7 nm, depending on composition. Modulation of the droplet size is possible by varying the water to DOSS molar ratio and DOSS to IPM ratio. The second goal of this work was the preparation of silver sulfadiazine (AgSD) nanoparticles. It was hypothesized that two separate microemulsions containing dispersed aqueous droplets of either sodium sulfadiazine or silver nitrate would react when mixed. The DLS results are consistent with the successful formation of submicron AgSD crystals.

The use of Flammacerium in British Burns Units

INTRODUCTION

Flammacerium (cerium nitrate-silver sulphadiazine) is marketed throughout Europe, but is only available in UK on a named patient basis. Anecdotally it is widely used in civilian burns units across the country despite the regulatory constraint, although little literature exists regarding its use in UK. We designed a postal survey to assess the use of Flammacerium countrywide and whether its 'named patient only' designation causes problems in treating burns patients.

METHODS

Postal questionnaires were sent to the directors of the 18 adult burns units listed by the British Burns Association, requesting information on the use of Flammacerium. The indications and limitations of its use were recorded, as were any problems obtaining supplies. Finally, burns units were asked if they would like to see Flammacerium fully licensed in this country.

RESULTS

Replies were received from 14 units (response rate=78%). Six units use Flammacerium frequently, six occasionally and two units never use it. It is used in those patients not undergoing early wound excision and closure because of co-morbidity, general age or frailty, paucity of donor sites or mixed depth pattern burns. It was generally used in the belief that it reduces the inflammatory response to burn injury (8/12), decreases bacterial colonization (10/12) and provides a firm eschar for easier wound management (11/12). Although 8 units had no problems with supplies of the agent, 10 respondents indicated they would like to see Flammacerium fully licensed in UK.

Treatment of partial-thickness burns: a prospective, randomized trial using Transcyte

BACKGROUND

The purpose of the present study was to compare the effectiveness of three burns dressings (TransCyte, a bio-engineered skin substitute; Biobrane; and Silvazine cream (silver sulphadiazine and 0.2% chlorhexidine)), in treating children with partial-thickness burns. The primary objective was to determine the days until > or =90% re-epithelialization. The secondary objectives were to evaluate the number of wounds requiring autografting and the number of dressing changes/local wound care required.

METHODS

Study wounds were identified on each patient and the patients were randomized to receive TransCyte or Biobrane or Silvazine. Assessment of study wound closure began at 2 days after treatment and continued at least every other day thereafter until the wounds re-epithelialized or were autografted. A laser Doppler imaging system was used as an adjunct to assessing the depth of the burn.

RESULTS

Thirty-three patients with 58 wound sites enrolled in the study (TransCyte, n = 20, Biobrane, n = 17; Silvazine, n = 21). Mean time to re-epithelialization was 7.5 days for TransCyte, 9.5 days for Biobrane, and 11.2 days for Silvazine. The number of wounds requiring autografting were 5/21 (24%) for Silvazine, 3/17 (17%) for Biobrane, and 1/20 (5%) for TransCyte.

CONCLUSIONS

When used in partial-thickness burns in children, TransCyte promotes fastest re-epithelialization and required less overall dressings then Biobrane or Silvazine. Patients who received Silvazine or Biobrane require more autografting than those treated with TransCyte.

[Hydro-cellular dressing and silver sulfadiazine. Evaluation of its combination in the treatment of infected skin ulcers]

The authors carried out an observational, descriptive, prospective and multi-centric study on 49 infected lesions which had clinical signs of local infection as well as infection from a positive sprinkler method culture. These lesions were treated over a three week period with argentic sulfadiazine and a semi-permeable dressing; afterward, treatment continued for seven weeks more based on cures in a humid environment by means of a semi-permeable dressing. After three weeks of treatment, two-thirds of these lesions showed a negative exudative culture, the number of strains present in the rest of the cultures diminished to at least half of those present at the start of this study. 15 of these lesions completely closed over during the period of study (mean = 46.73 +/- 22.74 days) and the absolute cicatrisation surface area varied, on average, from 23.46 square cm at the start to 12.39 square cm at the end of this study. In relation to the relative cicatrisation an average reduction of 76.5% (IC 95= (66.85% - 86.2%)) occurred. Variance analysis (ANOVA) over repeated measurements established significant differences (p = 0.001) having a tendency toward a lineal decrease. The authors also found statistically significant differences regarding the mean relative cicatrisation in the subgroup having lesions which stopped being infected during the third week of treatment when compared to those lesions which continued being infected. In conclusion, the authors state the topical treatment using argentic sulfadiazine in combination with a semi-permeable dressing has been favorable in treating two of every three lesions which stopped being infected in the third week of treatment, furthermore, this treatment produced a reduction in the size of these lesions, both in terms of the absolute mean cicatrisation area as in the relative mean cicatrisation area cicatrisation area for the lesion group in this study.

Endotracheal Tubes Coated with Antiseptics Decrease Bacterial Colonization of the Ventilator Circuits, Lungs, and Endotracheal Tube

Background

Formation of a bacterial biofilm within the endotracheal tube (ETT) after tracheal intubation is rapid and represents a ready source of lung bacterial colonization. The authors investigated bacterial colonization of the ventilator circuit, the ETT, and the lungs when the ETT was coated with silver-sulfadiazine and chlorhexidine in polyurethane, using no bacterial/viral filter attached to the ETT.

Methods

Sixteen sheep were randomized into two groups. Eight sheep were intubated with a standard ETT (control group), and eight were intubated with a coated ETT (study group). Animals were mechanically ventilated for 24 h. At autopsy, the authors sampled the trachea, bronchi, lobar parenchyma, and ETT for quantitative bacterial cultures. Qualitative bacterial cultures were obtained from the filter, humidifier, inspiratory and expiratory lines, and water trap. ETTs were analyzed with light microscopy, scanning electron microscopy, and laser scanning confocal microscopy.

Results

In the control group, all eight ETTs were heavily colonized (10(5)-10(8) colony-forming units [cfu]/g), forming a thick biofilm. The ventilator circuit was always colonized. Pathogenic bacteria colonized the trachea and the lungs in five of eight sheep (up to 10(9) cfu/g). In the study group, seven of eight ETTs and their ventilator circuits showed no growth, with absence of a biofilm; one ETT and the respective ventilator circuit showed low bacterial growth (10(3)-10(4) cfu/g). The trachea was colonized in three sheep, although lungs and bronchi showed no bacterial growth, except for one bronchus in one sheep.

Conclusions

Coated ETTs induced a nonsignificant reduction of the tracheal colonization, eliminated (seven of eight) or reduced (one of eight) bacterial colonization of the ETT and ventilator circuits, and prevented lung bacterial colonization.

Der Einsatz der V.A.C.®-Therapie bei der Verminderung des „Nachbrennens”: Erste Ergebnisse in der Verbrennungsbehandlung

Thermal injury applied to living tissue results in zones of injury. Cell death is complete in the zone of coagulation. Beneath this area, there is the zone of lesser injury, where most of the cells are initially viable. If this zone of stasis is not reversed, the burn wound will progress. One of the major aspects to prevent progression is to reduce the edema formation and to preserve microcirculation. We present our first experiences to prevent the progression by use of topical negative pressure. Within the last months, all patients with bilateral partial thickness hand burns were included into this treatment protocol. Within one patient, one hand was treated with the V.A.C. (KCI, Austria), the contra lateral one by use of Flammazine (Smith and Nephew, Germany). Our first observations and data indicate, that both important factors (edema and microcirculation) could be influenced positively by use of the V.A.C.

Catheter-associated infections: pathogenesis affects prevention

Intravascular catheters and urinary catheters are the 2 most commonly inserted medical devices in the United States, and they are likewise the two most common causes of nosocomially acquired bloodstream infection. Biofilm formation on the surfaces of indwelling catheters is central to the pathogenesis of infection of both types of catheters. The cornerstone to any preventive strategy of intravascular catheter infections is strict attention to infection control practices. Antimicrobial-impregnated intravascular catheters are a useful adjunction to infection control measures. Prevention of urinary catheter-associated infection is hindered by the numbers and types of organisms present in the periurethral area as well as by the typically longer duration of catheter placement. Antimicrobial agents in general have not been effective in preventing catheter-associated urinary tract infection in persons with long-term, indwelling urethral catheters. Preventive strategies that avoid the use of antimicrobial agents may be necessary in this population.

A randomized, controlled trial of tea tree topical preparations versus a standard topical regimen for the clearance of MRSA colonization

Two topical MRSA eradication regimes were compared in hospital patients: a standard treatment included mupirocin 2% nasal ointment, chlorhexidine gluconate 4% soap, silver sulfadiazine 1% cream versus a tea tree oil regimen, which included tea tree 10% cream, tea tree 5% body wash, both given for five days. One hundred and fourteen patients received standard treatment and 56 (49%) were cleared of MRSA carriage. One hundred and ten received tea tree oil regimen and 46 (41%) were cleared. There was no significant difference between treatment regimens (Fisher's exact test; P = 0.0286). Mupirocin was significantly more effective at clearing nasal carriage (78%) than tea tree cream (47%; P = 0.0001) but tea tree treatment was more effective than chlorhexidine or silver sulfadiazine at clearing superficial skin sites and skin lesions. The tea tree preparations were effective, safe and well tolerated and could be considered in regimens for eradication of MRSA carriage.

Diagnosis and treatment of four stallions, carriers of the contagious metritis organism--case report

Contagious Equine Metritis (CEM), a venereal disease of horses caused by the bacterium Taylorella equigenitalis, was first diagnosed in 1977 and subsequently spread to many nations [Proc 24th AM Assoc Equine Pract (1979) 287]. The disease was confirmed in the United States in 1978 [Proc Am Assoc Equine Pract (1983) 295]. Specific regulatory procedures for this disease have been established in the United States and 37 other countries. From 1999 through 2001, four of 120 imported European stallions tested positive for CEM at a quarantine facility in Darlington, MD, USA. Two stallions were identified by positive bacterial cultures for T. equigenitalis on arrival. The other two positive stallions were negative on initial bacterial cultures, but were identified as CEM carriers when test mares (that they had mated) were culture-positive for T. equigenitalis. Since T. equigenitalis, is a fastidious slow-growing coccobacillus, additional sets of samples taken over a interval might be required to ensure positive stallions are detected before mating test mares. Likewise, additional sets of samples taken over a long interval after treatment of a stallion for CEM might be required to ensure that positive stallions treated for CEM are detected before mating test mares. Aggressive systemic antibiotic therapy accompanied by routine topical therapy might be required to treat some CEM-positive stallions.

Topical treatment of partial thickness burns by silver sulfadiazine plus hyaluronic acid compared to silver sulfadiazine alone: a double-blind, clinical study

Since its introduction into clinical practice in 1967 by Charles Fox Jr., silver sulfadiazine has been the gold standard for topical burn therapy. The addition to it of hyaluronic acid, which forms a substantial part of the human tissue intercellular matrix, is aimed at overcoming one of its very few disadvantages, i.e. prolongation of the wound re-epithelialization process. Since both hyaluronic acid and silver sulfadiazine have been used in therapy for decades and their efficacy is well documented, a topical treatment combining these two agents was formulated. The aim of the study was to investigate the efficacy and tolerability of a cream containing a hyaluronic acid/silver sulfadiazine fixed combination, compared with silver sulfadiazine cream alone, for the treatment of superficial and deep second-degree burns in a prospective, double-blind, controlled clinical study. The findings of the study confirmed that the association of the two compounds in a new topical treatment significantly reduced the healing time and significantly accelerated the reduction of local edema occurring shortly after injury. Furthermore, this new hyaluronic acid and silver sulfadiazine formulation has proven to have favorable antibacterial, anti-edematous and local analgesic effects, together with a clear stimulatory activity on the re-epithelialization process. This product may, therefore, significantly enrich the assortment of topical medications available for the treatment of burns and skin defects of other origin.

Scar-localized argyria secondary to silver sulfadiazine cream

Silver sulfadiazine cream is a topical antibacterial agent that combines the antibacterial effects of both silver and sulfadiazine. Its reported cutaneous side effects include hypersensitivity reactions, allergic contact dermatitis, erythema multiforme, and systemic argyria. We report the case of a patient who had localized argyria develop in a scar after the use of silver sulfadiazine cream. In this case, the silver sulfadiazine cream was applied to and argyria developed within a postsurgical wound and area of severe contact dermatitis.

Effect of topically applied silver sulfadiazine on fibroblast cell proliferation and biomechanical properties of the wound

The effect of silver sulfadiazine (SSD) on the proliferation of human dermal fibroblast (HDF) was studied to determine the impact of the drug on the wound healing process and dermal mechanical strength. Human dermal fibroblasts were cultured to 80% confluency using DMEM with 10% FBS and viability of the cell was estimated using neutral red assay. In addition, the 2nd degree burn wound was prepared on the anterior part of rabbit ear skin and dressings containing SSD were applied for 96 h. Presence of inflammatory cells and degree of re-epithelialization were investigated in the wound. After 15 day of the induction of burn wounds, the treated area was excised and dermal mechanical strength was quantitatively measured with a constant speed tensiometer. SSD was found to be highly cyto-toxic in cultured HDF cells. The topical application of SSD (2%) could control the infection as evidenced by the lack of accumulation of inflammatory cells in histological evaluation. Therefore, these observations suggested that the impairment of dermal regeneration and decreased mechanical strength of dermal tissue was resulted from the cyto-toxic effect of SSD on dermal cells. Since the decreased mechanical strength may lead to reduction in resilience, toughness and maximum extension of the tissue, the identification of optimum dose for SSD that limits infection while minimizes the cyto-toxic effect may be clinically relevant.

New choices for central venous catheters: potential financial implications

OBJECTIVE

To determine the cost-effectiveness of the newer antiseptic and antibiotic-impregnated central venous catheters (CVCs) relative to uncoated CVCs and to each other.

DESIGN

Decision model analysis of the cost and efficacy of CVCs coated with either chlorhexidine silver sulfadiazine (CSS) or rifampin-minocycline (RM) at preventing catheter-related bloodstream infections (CRBSIs). The primary outcome is the incremental cost (or savings) to prevent one additional CRBSI. Model estimates are derived from prospective trials of the CSS and RM CVCs and from other studies describing the costs of CRBSIs.

SETTING AND PATIENTS

Hypothetical cohort of 1,000 patients requiring placement of a CVC.

INTERVENTIONS

In the model, patients were managed with either an uncoated CVC, CSS CVC, or RM CVC.

MEASUREMENTS AND MAIN RESULTS

The incremental cost-effectiveness of the treated CVCs was calculated as the savings resulting from CRBSIs averted less the additional costs of the newer devices. Sensitivity analysis of the effect of the major clinical inputs was performed. For the base case analysis, we assumed the incidence of CRBSIs was 3.3% with traditional catheters and that the CSS and RM CVC conferred a relative risk reduction for the development of CRBSIs of 60% and 85%, respectively. Despite their significantly higher cost than older catheters, both novel CVCs yield significant savings. Employing either of the treated CVCs saves approximately $10,000 per CRBSI prevented (relative to standard catheters). Comparing the RM CVC to the CSS CVC revealed the RM product to be economically superior, saving nearly $9,600 per CRBSI averted and $81 per patient in the cohort. For sensitivity analysis, we adjusted all model variables by 50% individually and then simultaneously. This demonstrated the model to be most sensitive to the cost of a CRBSI; however, with all inputs skewed by 50% against both the CSS CVC and the RM CVC, these devices remained economically attractive. Under this scenario, use of either treated device was less costly.

CONCLUSIONS

Utilization of antiseptic and antibiotic-impregnated CVCs represent an attractive alternative for the prevention of CRBSIs and may lead to significant savings. Of the two newer, coated devices, the RM CVC performs better financially. These observations hold over a range of estimates for our model inputs.

Evaluation of the antimicrobial efficacy of urinary catheters impregnated with antiseptics in an in vitro urinary tract model

OBJECTIVES

To evaluate the long-term efficacy of urinary Foley catheters (latex and silicone) impregnated with (1) chlorhexidine and silver sulfadiazine (CXS) and (2) chlorhexidine, silver sulfadiazine, and triclosan (CXST) in inhibiting extra-luminal bacterial adherence and to compare their efficacy with that of silver hydrogel latex (SH) and nitrofurazone-treated silicone (NF) catheters.

DESIGN

The antimicrobial spectrum of these catheters was evaluated using a zone of inhibition assay. A novel in vitro urinary tract model was developed to study the potential in vivo efficacy of antimicrobial catheters in preventing extraluminal bacterial colonization. The "meatus" was inoculated daily with Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, Enterococcus faecalis, Pseudomonas aerginosa, and Candida albicans. The "bladder" portion of the model was cultured daily to determine bacterial growth.

RESULTS

Both CXS and CXST catheters had a broader antimicrobial spectrum than SH and NF catheters. In the in vitro model, CXST latex and silicone catheters exhibited significantly better efficacy (3 to 25days) against uropathogens, compared with CXS (1 to 14 days) and control (0 to 5 days) catheters (P = .01). CXST latex catheters exhibited significantly longer protection against Staphylococcus aureus, Staphylococcus epidermidis, Escherichia coli, and Pseudomonas aeruginosa, compared with SH catheters (P = .01). CXST silicone catheters resisted colonization with Staphylococcus aureus and Staphylococcus epidermidis for a significantly longer period (23 to 24 days) than did NF catheters (9 to 11 days) (P = .01).

CONCLUSION

Catheters impregnated with synergistic combinations of chlorhexidine, silver sulfadiazine, and triclosan exhibited broad-spectrum, long-term resistance against microbial colonization on their outer surfaces.

Silver-sulfadiazine eschar pigmentation mimics invasive wound infection: a case report

A 3-year-old girl with 52% TBSA scalds, mostly partial thickness, was treated topically with 5% mafenide acetate solution and 1% silver sulfadiazine cream. All blood cultures and wound swabs were negative for the first 5 days. On day 6 gram-negative bacteria and yeast forms were isolated from her wounds. High fever and leukocytosis were present and the child was treated with intravenous ampicillin and gentamicin according to sensitivity bacteriogram. The bacteria were identified as Pseudomonas aeruginosa and the yeast was Candida tropicalis. On day 7, Escherichia coli was identified in blood cultures and intravenous cefixime was added. Amphotericin B was added on day 9 when blood cultures grew Candida tropicalis and Burkholderia cepacia. On day 13 dark pigmentation foci developed on some areas of partial-thickness burns in the back, resembling invasive wound infection. White blood cell count was 14,300 cells/mm3, and her body temperature reached 39.7 degrees C. Cultures from the pigmented areas were negative, and biopsies revealed deposits of silver. Most of the areas healed uneventfully, and only about 8% TBSA needed grafting, including some of the pigmented areas. No residual pigmentation remained on discharge.

Effect of central venous catheter type on infections: a prospective clinical trial

This study reports on a block clinical trial of two types of central venous catheters (CVCS): antiseptic-impregnated catheters (AIC) and non-impregnated catheters (non-AIC), on catheter tip colonization and bacteraemia. In total, 500 catheters were inserted in 390 patients over the 18 month study period, 260 (52.0%) AIC and 240 (48.0%) non-AIC. Of these, 460 (92.0%) tips (237 AIC and 223 non-AIC) were collected. While significantly fewer AIC, 14 (5.9%), than non-AIC, 30 (13.5%), catheters were colonized (P<0.01), there was no difference in the rates of bacteraemias in the two groups (0.8% vs. 2.7%, respectively, P=0.16). There were 6.87 (95% CI 3.38-14.26) and 16.92 (95% CI 10.61-27.12) colonized AIC and non-AIC catheters, respectively, per 1000 catheter days, a difference that was significant (P<0.01). However, no difference emerged between bacteraemias in AIC and non-AIC catheters per 1000 catheter days measured at 0.98 (95% CI 0.24-5.54) and 3.38 (95% CI 1.29-9.34), respectively (P=0.10). Of the 444 CVCs that were sited in the subclavian or jugular veins and had tips collected, significantly more catheters were colonized in the jugular group, 19 (20%), compared with the subclavian group, 24 (6.9%; P< or =0.01). Overall, the low rates of colonization and bacteraemia may be explained by the population studied, the policies used and the employment of a clinical nurse dedicated to CVC management.

Which antimicrobial impregnated central venous catheter should we use? Modeling the costs and outcomes of antimicrobial catheter use

BACKGROUND

Catheter-related bloodstream infections are costly and associated with substantial morbidity and mortality. Trials suggest that central venous catheters impregnated with minocycline/rifampin, although more expensive, are clinically superior to chlorhexidine/silver sulfadiazine impregnated catheters. It remains unclear whether minocycline/rifampin catheters are cost-effective for all high-risk patients or only those requiring longer-term catheterization.

METHODS

We developed a series of decision models with patient-level clinical trial data to determine whether minocycline/rifampin catheters are cost-effective for patients requiring various durations of catheterization. We calculated incremental cost-effectiveness ratios for patients catheterized for durations ranging from 1 to 25 days.

RESULTS

The data were too sparse to estimate cost-effectiveness for patients catheterized less than 8 days. The probability that minocycline/rifampin catheters were cost-effective compared with chlorhexidine/silver sulfadiazine catheters in patients catheterized for 8 days was 91%. The probability that the minocycline/rifampin catheters in patients catheterized 13 days or longer resulted in cost savings was more than 95%.

CONCLUSIONS

Our analysis suggests that central venous catheters coated with minocycline/rifampin are cost-effective for patients catheterized for at least 1 week and lead to overall cost savings when patients are catheterized for 2 weeks or longer. Policies for the use of antimicrobial catheters in high-risk patients should reflect patients' expected duration of catheterization.

Modulation of inflammatory and catabolic responses in severely burned children by early burn wound excision in the first 24 hours

HYPOTHESIS

Early burn wound excision modulates the hypermetabolic response in severe pediatric burn injuries.

DESIGN

Before-after trial.

SETTING

A 30-bed burn referral center in a private, university-affiliated hospital.

METHODS

We studied 35 severely burned children who were divided into 2 groups. One group (n = 20) was treated with early burn wound excision within 24 hours after the injury. The second group (n = 15) was treated conservatively with silver sulfadiazine in other burn facilities for 5 days, and burn wounds were surgically excised when patients were admitted to our burn center on day 6 after the injury. Data compiled included oxygen consumption and acute-phase protein, interleukin 1beta; interleukin 6, interleukin 10, tumor necrosis factor alpha, and anabolic hormone (growth hormone, insulinlike growth factor type 1) levels preoperatively and 24 hours and 5 days postoperatively.

MAIN OUTCOME MEASURES

Acute-phase and hypermetabolic responses.

RESULTS

Early burn wound excision abrogated the hypermetabolic response in pediatric burn patients. Patients who underwent conservative treatment had a significantly more severe inflammatory and hypermetabolic response at the same time interval and significantly lower levels of anabolic hormones.

CONCLUSIONS

Early burn wound excision is a safe therapeutic approach that modulates the hypermetabolic response after burn injury. It was superior to the conservative treatment of silver sulfadiazine and delayed excision, and it should be considered when treating all severe full-thickness burns.

Effects of topical application of antimicrobials and bandaging on healing and granulation tissue formation in wounds of the distal aspect of the limbs in horses

OBJECTIVE

To determine whether povidone iodine ointment or 2 forms of silver sulfadiazine applied topically to wounds of the distal aspect of the limbs in horses affect the rate of second intention healing and to evaluate the additional influence of bandaging with these antimicrobials on granulation tissue formation.

ANIMALS

6 healthy adult horses.

PROCEDURE

Six standardized 2.5-cm2 skin wounds/horse were distributed between the dorsomedial surfaces of the metacarpi and metatarsi. One of the following 6 treatments was applied to each wound: 1% silver sulfadiazine cream with bandage, 1% silver sulfadiazine slow-release matrix with bandage, 1% silver sulfadiazine slow-release matrix without bandage, povidone-iodine ointment with bandage, untreated control with bandage, and untreated control without bandage. Wound area, granulation tissue area, and perimeter were measured by use of planimetry software applied to digital images. Exuberant granulation tissue was excised when present. Days until healing, rate of healing parameter, rate of contraction, and epithelialization were compared among wound treatment groups.

RESULTS

Healing parameters and mean days to healing did not differ significantly among any of the wound treatment groups. Percentage wound contraction and rate of epithelialization were similar among wound treatments. All bandaged wounds produced exuberant granulation tissue, which was surgically excised; none of the unbandaged wounds produced exuberant granulation tissue.

CONCLUSIONS AND CLINICAL RELEVANCE

When exuberant granulation tissue is removed, rates of epithelialization and wound contraction were not different among wound treatment groups, whether bandaged or unbandaged. Topical application of 1% silver sulfadiazine slow-release matrix on unbandaged wounds induced the same result as medications applied beneath bandages, but without exuberant granulation tissue formation.

Comparison of silver sulfadiazine 1%, mupirocin 2%, and fusidic acid 2% for topical antibacterial effect in methicillin-resistant staphylococci-infected, full-skin thickness rat burn wounds

Silver sulfadiazine 1%, mupirocin 2%, and fusidic acid 2% were compared to assess the antibacterial effect of a once-daily application on experimental rat 15% full-skin thickness burn wounds seeded 24 hours earlier with a 10 standard strain of methicillin-resistant staphylococci. The quantitative counts of seeded organism in burn eschar and subjacent muscle were determined at postburn day 7, beside the cultures of blood and lung biopsies. All tested topical agents were equally effective against methicillin-resistant in reducing local burn wound bacterial count and preventing systemic infection.

The effects of a high-potency topical steroid on cutaneous healing of burns in pigs

OBJECTIVE

Burns are dynamic injuries that tend to progress over the course of several days. Steroids inhibit the formation of vasoconstrictive prostanoids that may contribute to this progression of injury. The authors hypothesized that adding topical steroids to a standard antimicrobial agent would reduce the progression of burns and accelerate reepithelialization without increasing infection rates.

METHODS

This was a prospective, blinded, controlled, experimental trial. Forty-eight standardized second-degree burns were created by applying an aluminum bar preheated to 80 degrees C to the flanks of isoflurane-anesthetized young pigs for 20 seconds. Three equal sets of 16 burns were randomly treated with silver sulfadiazine cream (SSD), clobetasol propionate 0.05% (CP), or both (SSD+CP). Daily dressing changes were performed for 14 days. Full-thickness biopsies were taken after injury and at one, two, seven, ten, and 14 days for blinded histopathological evaluation using hematoxylin and eosin (H&E) staining. The primary outcome was the % reepithelialization (REP) calculated by dividing the length of the neoepidermis by the section's total length (interobserver correlation = 0.99). Depth of injury was measured for each dermal element (collagen; epithelial, mesenchymal, and vascular cells; and vessel thrombosis). Comparisons across groups were performed using one-way analysis of variance (ANOVA). A repeated-measures ANOVA was used to compare injury depths over time. This study had 80% power to detect a 33-percentage point difference in REP across groups (two-tailed alpha = 0.05).

RESULTS

Pretreatment burn depths were similar across groups. While burn depth changed over time, there was no difference between the groups in burn injury progression. There was no difference across the groups in REP or infection rates at all times.

CONCLUSIONS

Addition of a potent topical steroid to standard antimicrobial topical agents does not reduce burn depth or accelerate reepithelialization after burns.

A comparison of topical Phenytoin with Silverex in the treatment of superficial dermal burn wounds

OBJECTIVE

To compare topical diphenylhydantion (Phenytoin) with silver sulphadiazine/chlorhexidine (Silverex) in terms of rate of wound healing, analgesic and antibacterial properties in small to moderate-sized (< 30% TBSA) superficial dermal (second degree) burn wounds.

DESIGN

A prospective randomized controlled study.

SETTING

Surgical wards, Muhimbili National Hospital from July 2000 to February 2001.

SUBJECTS

Sixty four patients with acute burns, 32 in each group.

INTERVENTIONS

Study group treated by sprinkling Phenytoin powder and control group by sprinkling Silverex powder on the wounds for 14 days or until the wound epithelialised or was ready for skin grafting. The data collected included demographic characteristics of patients, aetiology of burn injury, circumstances of injury, site and extent of burns, pus discharge and smell from the wound, pain and discomfort from the wound, bacterial cultures of wound swabs, rate of reduction in wound size and outcome of treatment.

RESULTS

The study enrolled 33 male and 31 female patients, 69% being children under five years of age. Hot liquids (80%) and open flames (20%) were the only causes of burns. In 97% of patients injury was due to domestic accidents. In half of the patients burns involved the trunk, and 52% of all patients had less than 15% total body surface burnt. Pus discharge was recorded in 59% of Phenytoin-treated and 75% in Silverex-treated patients while foul smell was noted in 19% and 31% of cases respectively. There were more negative bacterial wound cultures in Phenytoin-than Silverex-treated wounds on day five and day 10 of treatment, the difference being statistically significant (p < 0.01 and 0.001 respectively). There was also a statistically significant difference in wound pain in favour of Phenytoin (p < 0.01). There was no statistically significant difference in the rate of healing in the two groups.

CONCLUSION

Phenytoin is a cheap and easy-to-use medicament, effective in suppressing burn wound bacteria and relieving pain thereby promoting healing, and may be advocated for the purpose in resource-scarce environments.

Complete osseous regeneration of a large skull defect in a patient with cutis aplasia: a conservative approach

Cutis aplasia (or aplasia cutis congenita) is a congenital absence of all skin layers, often extending through bone. This defect usually occurs in the scalp and can be extensive, exposing the dura mater, and deeper meninges. Treatment regimens for cutis aplasia have included early operative intervention, including skin and bone grafts, local scalp flaps, or free flaps to close the defect. In addition to the significant perioperative risks, these invasive procedures may inhibit the osteogenic potential of the dura to initiate and sustain bony closure of the defect. We report a case of an infant with Adams-Oliver syndrome and cutis aplasia involving a large portion of the skull that was treated conservatively with topical Silvadene dressings. No surgical treatment of bone or soft tissue reconstruction was necessary. This case report is the first to our knowledge to document complete bony restoration of the cranial vault through serial three-dimensional CT scans. The intensive therapeutic intervention in this case report allowed early discharge from the hospital, a gradual amelioration of the patient's alopecia as the hair-bearing scalp slowly covered the defect, and precluded the need for any subsequent bony reconstruction of the cranial vault. We hypothesize that conservative treatment of cutis aplasia maintains dural induction of osseous regeneration, and any treatment plan for bony defects of cutis aplasia should consider maintenance of dural integrity. Although further investigation is warranted, an initial trial of antimicrobial dressing care might optimally promote secondary closure of the cranial vault without the need for surgical intervention.

An infection-preventing bilayered collagen membrane containing antibiotic-loaded hyaluronan microparticles: physical and biological properties

An infection-preventing bilayered membrane consisting of a dense and porous collagen membrane has been developed. The membrane was fabricated using a combined freeze-drying/air-drying method. Hyaluronan (HA) microparticles containing silver sulfadiazine (AgSD) were fabricated by gelling an HA solution with calcium chloride and were incorporated into collagen layers to allow the sustained release of AgSD. In vitro biodegradability of the membrane and the release of AgSD from the membrane could be controlled by cross-linking the membrane with ultraviolet (UV) irradiation. In a cytotoxicity test, cellular damage was minimized by the sustained release of AgSD from dressings. The antibacterial capacity of the material against Pseudomonas aeruginosa was investigated using the Bauer-Kirby disk diffusion test, and bacterial growth was found to be inhibited for 4 days. In vivo tests showed that the bilayered membrane was associated with greater tissue regeneration than a polymeric membrane and with no infection-related biological signs.

[A case of primary pyoderma-like aspergillosis occurring in a patient with a cervical spinal cord injury]

A 65-year-old man had tetraplegia caused by a cervical spinal cord injury, and could only lie in bed with a respirator. On the 14 th day of hospitalization, a rash developed on his back. The eruption grew rapidly, and became a giant erythematous plaque with ulcer, pustules, and red papules. Direct KOH examination showed branching Aspergillus hyphae. A slide culture showed subglobose shaped vesicles with phialides. Based on these findings, the case was diagnosed as primary pyoderma-like aspergillosis caused by Aspergillus fumigatus. He was treated with bifonazole and sulfadiazine silver, and one month later no Aspergillus hyphae were observed either by direct KOH examination or by culture. The patient died about 2 months later, however, because of aggravation of his general condition. Careful observation is necessary for compromised or unmoving patients with pyoderma-like aspergillosis.

Control of wound infections using a bilayer chitosan wound dressing with sustainable antibiotic delivery

A novel bilayer chitosan membrane was prepared by a combined wet/dry phase inversion method and evaluated as a wound dressing. This new type of bilayer chitosan wound dressing, consisting of a dense upper layer (skin layer) and a sponge-like lower layer (sublayer), is very suitable for use as a topical delivery of silver sulfadiazine (AgSD) for the control of wound infections. Physical characterization of the bilayer wound dressing showed that it has excellent oxygen permeability, that it controls the water vapor transmission rate, and that it promotes water uptake capability. AgSD dissolved from bilayer chitosan dressings to release silver and sulfadiazine. The release of sulfadiazine from the bilayer chitosan dressing displayed a burst release on the first day and then tapered off to a much slower release. However, the release of silver from the bilayer chitosan dressing displayed a slow release profile with a sustained increase of silver concentration. The cultures of Pseudomonas aeruginosa and Staphylococcus aureus in agar plates showed effective antimicrobial activity for 1 week. In vivo antibacterial tests confirmed that this wound dressing is effective for long-term inhibition of the growth of Pseudomonas aeruginosa and Staphylococcus aureus at an infected wound site. The results in this study indicate that the AgSD-incorporated bilayer chitosan wound dressing may be a material with potential antibacterial capability for the treatment of infected wounds.

Silver-coated endotracheal tubes associated with reduced bacterial burden in the lungs of mechanically ventilated dogs

STUDY OBJECTIVES

To evaluate the influence of silver-coated endotracheal tubes on the lung bacterial burden of mechanically ventilated dogs.

DESIGN

Randomized, double-blinded, controlled experiment.

SETTING

Animal research facility of a regional medical university.

PATIENTS OR PARTICIPANTS

Eleven healthy adult dogs.

INTERVENTIONS

The dogs were intubated either with cuffed, noncoated endotracheal tubes or with endotracheal tubes having a novel antimicrobial silver hydrogel coating and were challenged with buccal administration of Pseudomonas aeruginosa.

MEASUREMENTS AND RESULTS

The silver coating delayed the appearance of bacteria on the inner surface of the endotracheal tubes ([mean +/- SD] duration of mechanical ventilation before appearance of bacteria, 3.2 +/- 0.8 days; mean duration of mechanical ventilation, 1.8 +/- 0.4 days; p = 0.016). The mean total aerobic bacterial burden in the lung parenchyma was statistically lower among the dogs receiving the silver-coated endotracheal tubes compared to those not receiving them (4.8 +/- 0.8 vs 5.4 +/- 9 log cfu/g lung tissue, respectively; p = 0.010). Pronounced differences were seen in the gross and histologic assessments of inflammation in the lung. Using an increasing severity scale of 0 to 12 to assess four components of histology (ie, hyperemia, edema, cellular infiltration, and bacterial presence), dogs receiving noncoated endotracheal tubes had statistically greater histology scores compared to dogs receiving silver-coated endotracheal tubes (7.1 plus minus 1.6 vs 2.8 plus minus 1.2, respectively; p < 0.001).

CONCLUSION

These results suggest that the silver coating of endotracheal tubes may delay the onset of and decrease the severity of lung colonization by aerobic bacteria. Based on these results, clinical studies are planned to determine the safety and clinical efficacy of silver-coated endotracheal tubes in patients requiring mechanical ventilation in the ICU setting.

[Increased serum and urinary levels of silver during treatment with topical silver sulfadiazine]

BACKGROUND

Argyria, induced by prolonged absorption, is often of professional or medical origin. We report two cases of per cutaneous intoxication with topical silver sulfadiazine.

CASE REPORTS

A 64 year-old hypertensive, diabetic woman presented bilateral venous ulcers on the legs. She had applied 100 g of silver sulfadiazine 1 p. 100 cream per week for the past 18 months. Silver concentration in blood high: 38 microgram/l (N<0.5) and led to renal dysfunction, without ocular or hepatic abnormality. A 19 year-old woman was treated with topical silver sulfadiazine for thermic cutaneous burns on legs. Renal and hepatic function was normal but silver concentration in blood was high at 440 microgram/l (N<0) with urinary excretion of silver at 12 microgram/l (N=0).

DISCUSSION

Silver, from prolonged and excessive use of topical silver sulfadiazine, deposits in large amounts throughout the body: skin, labial mucosa, gingiva, kidney, liver and cornea. Monitoring concentration of silver in blood and/or urine is necessary, especially in patients treated with silver sulfadiazine cream for cutaneous burns. Indeed, silver is rapidly absorbed through the burn wound. It provokes hepatic, renal and neurologic tissue toxicity. Renal and hepatic function tests are not correlated with serum silver levels.

CONCLUSION

The potential for silver toxicity is a direct consequence of applying silver sulfadiazine to extensive burn wounds. Hence monitoring concentrations of silver in blood and/or urine of patients receiving this treatment is recommended.

Comparison of propolis skin cream to silver sulfadiazine: a naturopathic alternative to antibiotics in treatment of minor burns

BACKGROUND

Propolis, a naturopathic substance derived from bees wax extract, has recently been praised for its antimicrobial, anti-inflammatory, and cicatrization-enhancing properties.

OBJECTIVE

In our study, we compare these properties in a high-grade Brazilian propolis skin cream directly with silver sulfadiazene (SSD) in the treatment of minor burns (superficial second degree) in the ambulatory care setting (less than 20% total body surface area burned).

SETTINGS/LOCATION

The study was conducted at the burn clinic in Pronto Socorro para Queimaduras, Gioania, Brazil.

SUBJECT

Patients were admitted to the study only if their initial presentation for burn care was within 48 hours postinjury and if bilateral wounds of similar depth and quality were present.

INTERVENTIONS

Patients had propolis skin cream applied to one wound and SSD applied to the other selected wound on initial presentation and underwent debridement and dressings change the following morning. Patients subsequently returned to the clinic every 3 days to have the wounds checked and dressings changed. At these check-ups, wounds were cultured for microbial growth and photographed to document inflammation and cicatrization. Patients were instructed not to disturb their wounds or change their dressings at home, thus propolis skin cream and SSD were applied to the wounds only at the specified 3-day intervals.

RESULTS

Our preliminary results do not show any significant difference in microbial colonization between wounds treated with SSD and propolis skin cream, however, wounds treated with propolis skin cream consistently showed less inflammation and more rapid cicatrization then those treated with SSD.

CONCLUSION

Propolis skin cream appears to have a beneficial effects on the healing of partial thickness burn wounds. If dressings had been changed more frequent the antimicrobial and wound healing effects would have been enhanced.

Development of an artificial dermis preparation capable of silver sulfadiazine release

This article describes the antibacterial effects of an artificial dermis impregnated with silver sulfadiazine (Ag-SD) in vitro as well as in vivo. In the in vitro test, silver release from the artificial dermis impregnated with Ag-SD, by immersion in collagenase solution was controlled by the degradation of the collagen sponge. The artificial dermis impregnated with 3% or higher doses of Ag-SD completely suppressed the growth of Pseudomonas aeruginosa (Ps.) or Staphylococcus aureus (St.). The cytotoxicity test revealed that impregnation of 5% or higher doses of Ag-SD suppressed the growth of fibroblasts. However, when the artificial dermis impregnated with Ag-SD was implanted into full-thickness skin defects on the backs of guinea pigs, no tissue damage was histologically observed around the implanted site of the dermis. In the in vivo test, the artificial dermis impregnated with 10% Ag-SD, which was grafted on experimentally contaminated wounds in the backs of guinea pigs, macroscopically suppressed degradation of the collagen sponge, and significantly reduced the growth of both Ps. and St., compared with artificial dermis without Ag-SD. We conclude that collagen sponge impregnated with Ag-SD is a promising artificial dermis applicable to treat contaminated wounds.

Wound healing activity of the aqueous extract of Thespesia populnea fruit

Villagers have traditionally used the poultice prepared from the fruits of Thespesia populnea to treat a variety of skin ailments including wounds. In the present study, the aqueous extract of T. populnea fruit showed significant wound healing activity in the excision wound and incision wound models in rats following topical and oral administration, respectively.