Antimicrobial Selection in the Face of Nasal Methicillin-Resistant Staphylococcus aureus-Polymerase Chain Recombination Testing in Thermal Injury Patients.

Emergence of resistance to vancomycin and the increasing incidence of community-acquired methicillin-resistant Staphylococcus aureus (MRSA) warrant careful initiation of antimicrobial agents after nasal swab polymerase chain recombination (PCR) MRSA positive screen. Current MRSA PCR nasal swab (PCR) screening does not distinguish non-hospital-acquired strains. A retrospective, institutional review board-approved study of collected PCR screenings among 826 burn center admissions over a 23-month period assessed culture results, antimicrobial agents chosen, and patient demographics. Seventy-seven of the 826 were known chronic carriers (n = 11); had MRSA on initial PCR (n = 48); or converted to positive PCR screen on later testing (n = 18). The 48 patients with initial positive PCR were decolonized with mupirocin. MRSA carriers were not decolonized. The 18 patients who became PCR positive were also not decolonized with 10 having positive cultures. The 48 initial PCR nasal swab positive patients represented 5.8% of admissions. Demographic data did not differ among chronic carriers, initial PCR positive patients, nor those converting to PCR positive. Length of stay was shorter for initial PCR positive decolonized patients (P << .05) and they had a 35% of decrease in MRSA infection. All 11 chronic carriers became infected with MRSA; however, five had non-hospital-acquired MRSA and two solely non-hospital-acquired MRSA. For the 48 PCR positive patients, 17 had isolated MRSA and one having exclusively non-hospital-acquired MRSA. Of the 39 patients with isolated MRSA, 20 (43%) non-hospital-acquired MRSA. Non-hospital-acquired MRSA was 43%, however PCR fails to distinguish hospital-acquired MRSA from community-acquired MRSA.

Pyoderma gangrenosum: a difficult diagnosis best managed in a burn treatment center.

Pyoderma gangrenosum (PG) is a rare immunological disorder with inexplicable white blood cell infiltration into the epidermis with necrosis and excruciating pain. Diagnosis is by exclusion which delays proper treatment. Surgical intervention often exacerbates wounds. Between 2004 and 2010, seven patients with PG were admitted to our burn treatment center (BTC). Multiple treatment modalities were used on these patients. An institutional review board-approved retrospective study investigated seven PG BTC admissions. Demographic information, symptom onset, time to diagnosis, admission or transfer, length of stay (LOS), use of corticosteroids, and prior surgery were collected. The average time to PG diagnosis was 18.7 days and the average wound surface area was 3.9%. The average patient age was 64.6 years (median 66 years) and there were five men and two women patients. The average symptom onset was 70.5 days prior to BTC admission. The BTC wound care lasted 24 days. Six of the seven patients had lower extremity lesions vs one with lesions involving the abdomen. Inflammatory bowel disease was noted in two patients, one with malignant melanoma, and another with psoriasis. Corticosteroids were begun 1.75 days after admission for six of the seven patients. Of the seven PG patients, five had excision and/or skin grafting with vacuum-assisted wound closure used in four. Six patients were discharged, but one patient succumbed early to sepsis. Skin grafting often speeds up chronic wound closure; however for PG this causes progression of lesions. Persistent non-healing wounds with pain disproportionate to size may be PG. Prompt diagnosis and BTC specialized care greatly improve outcomes for PG patients.

Evaluation of Aquacel Ag for Autogenous Skin Donor Sites.

An ongoing objective of burn research is to evaluate wound dressings and develop new treatments to expedite wound healing. This was a single-center, prospective, randomized, controlled study to evaluate the effectiveness of Aquacel Ag as a dressing for autogenous skin donor sites compared with Xeroform. We hypothesized that donor sites treated with Aquacel Ag would heal faster. Patients were considered for enrollment if they required skin grafting with two donor sites >100 cm at least 2 inches apart. Dressings were observed daily starting on post-op day #2 until discharge and then weekly in the outpatient burn clinic. Assessments evaluated pain, infection, and reapplication. Photographs were taken on post-op day #2, upon "90% re-epithelialization," and at post-op day #30-45. Scar assessments and blinded photographic reviews were completed to assess cosmetic healing. Twenty-nine patients completed the study. Re-epithelialization occurred faster with Xeroform (15.2 days vs. 17.6 days). Daily pain scores were higher with Xeroform (6.72 vs. 5.68) and Aquacel Ag needed to be replaced more often (1.72 times vs. 0.10 times). Three patients developed donor site infections with Aquacel Ag. Scar scores between the donor sites were not statistically significant. The blinded photo review concluded that Xeroform had a better cosmetic outcome (24 vs. 10%). Although patients complained of more pain with Xeroform, it demonstrated shorter healing times and better cosmetic outcomes. Aquacel Ag needed to be replaced more often and represented the only three donor site infections.

Evaluation of the relationship between elevated vancomycin trough concentrations and increased efficacy and/or toxicity.

Isolation of Staphylococcus aureus with minimum inhibitory concentrations, 1 to 2 mg/L, suggests increasing vancomycin trough ranges, from 10 to 20 mg/L or even higher. Vancomycin troughs from 604 treatment courses from 560 patients with suspected or actual Gram-positive infection were analyzed with focus on potential toxicity/efficacy. Trough concentrations were required to be drawn within 15 to 45 minutes before the administration of at least the third vancomycin dose. Patients were retrospectively evaluated for their total daily dose and milligrams per kilograms per vancomycin dose. Data on the duration of vancomycin therapy, days to a normal temperature, and white blood cells were obtained. Data were stratified by trough concentration as <5, 5 to 10, and >10 mg/L to determine whether there was any relationship between response and trough concentration. Demographic data were obtained in 560 patients with 604 vancomycin treatment courses. For 361 patients with 379 separate treatment courses of vancomycin therapy no other nephrotoxic antimicrobial agent had been used. The greatest risk of vancomycin nephrotoxicity correlated with the duration of treatment. Using the log time to normal temperature, white blood cell count, heart rate, outcome from vancomycin therapy was assessed and no relationship could be demonstrated for the three vancomycin trough strata using analysis of variance (F < 2.62 for all parameters; p > .05). These data indicate that vancomycin trough elevation may not guarantee treatment success and that there may be no real benefit from higher vancomycin trough concentrations in thermal injury patients with burns <20% TBSA.

Trimethoprim-induced hyperkalemia in burn patients treated with intravenous or oral trimethoprim sulfamethoxazole for methicillin-resistant Staphylococcus aureus and other infections: nature or nurture?

Trimethoprim is well known to cause rashes; however, what is not commonly known is that it causes sudden and profound hyperkalemia in 10 to 20% of treated patients. The uniqueness of burn patients begs the question whether changes known to occur in these patients might also increase this trimethoprim effect. After institutional review board approval, a retrospective study evaluated 224 patients with thermal injury who had been treated with trimethoprim sulfamethoxazole (TMP-SMX), 24 of whom had underlying renal impairment (creatinine clearances <50 ml/min) and were excluded, leaving 200 patients for analysis. Three definitions of drug-induced hyperkalemia were used: 1) a ≥ 1 mEq/L rise, 2) a >0.8 mEq rise in potassium in <24 hours warranting early discontinuation of TMP-SMX, and 3) "marked" hyperkalemia defined as serum potassium of ≥ 5.5 mEq/L within 48 hours. A potassium level before trimethoprim exposure (TxK) and after TxK were collected retrospectively. Demographic data were analyzed with Student's t-test and trimethoprim dose alone, demonstrating a significant difference. Analysis of 200 patients exposed to trimethoprim demonstrated an elevation of potassium (first definition) in 31 patients (15.5%), a rapid change in serum potassium in two patients (second definition), and marked hyperkalemia (>5.5 mEq/L) in 13 patients (6.5%). Hyperkalemia never occurred in 166 of 200 patients (82%; before TxK, 3.9 ± 0.4; after TxK, 4.3 ± 0.5 mEq/L). Change in serum potassium among patients with hyperkalemia was 4.0 ± 0.5 mEq/L before TxK and 5.3 ± 0.7 mEq/L after TxK. Twelve published hyperkalemia risk factors were reviewed in these 200 patients and only history of hypertension and need for intubation was more common in those with hyperkalemia. A nearly 20% incidence of hyperkalemia and 6% serious hyperkalemia in burn patients is consistent with reports in patients without burn injury. These data also suggest that the metabolic and hormonal changes associated with burn injury do not increase further the genetically predisposed hyperkalemia resulting from exposure to trimethoprim. These data suggest patients treated with TMP-SMX should have routine serum potassium monitoring before discharge.

A comparison of clinical and microbiological efficacy of antibiotic regimens against Acinetobacter baumannii.

Acinetobacter baumannii represents a cunning pathogen with multiple resistance genes. The authors report their experience with the treatment of two multiple drug-resistant A. baumannii clones. At least one positive culture was noted in 359 patients and, 323 had sufficient data for analysis. Of these, 42 patients were colonized leaving 281 antibiotic-treated infected patients. The average age was 48.1 ± 20.6 years (mean ± standard deviation), total body burn surface area involvement (TBSA) was 30.8 ± 25%. Inhalation injury was confirmed by bronchoscopy in 238 of 323 (74%) patients. The day to the first A. baumannii culture was 7.9 ± 8.9 and 6.5 ± 8.8 days for the colonized and infected patients, respectively. Survival to discharge was 95.4% for colonized patients and 77.1% for infected patients. A total of 1425 sputum cultures, 123 catheter cultures from 40 patients, 1130 blood cultures from 176 patients, and 1925 wound cultures were obtained from the 318 infected patients (14 cultures per patient). Imipenem-cilastatin was first used in 162 patients, ampicillin-sulbactam in 40 patients, and cephalosporin in 41 patients. Imipenem-cilastatin was combined with ampicillin-sulbactam in 18 patients. Imipenem-cilastatin eradicated A. baumannii in 27%, caused persistence in 55%, and failure in 20%. Ampicillin-sulbactam eradicated A. baumannii in 17%, caused persistence in 51%, and failure in 34%. Imipenem-cilastatin combined with ampicillin-sulbactam eradicated 23% of the A. baumannii, with 54% persisting, and 23% failing therapy. Nonparametric analysis of three sets of 34 matched patients treated with imipenem-cilastatin, ampicillin-sulbactam, or a cephalosporin showed little difference in treatment outcomes. More rapid fever resolution and fewer positive cultures were noted in the imipenem-cilastatin treated group; however, length of stay was not different.

Use of nebulized antimicrobial agents in burned and mechanically ventilated patients with persistent Acinetobacter baumannii, Pseudomonas aeruginosa, or Enterobacteriacea.

BACKGROUND: Nebulized antibiotics are used to locally treat colonizations of multi-resistant organisms. Prior systemic nephrotoxic antibiotic use with serum creatinine rises warranted an alternative therapy in 69 ventilator-dependent patients with persisting sputum cultures and need for ventilatory support. MATERIALS AND METHODS: Following IRB approval, retrospective patient data were reviewed. Analysis included comparison of these 69 patients (71 treatments) to 142 Gram-negative infected burn patients matched for age and burn size. RESULTS: Mean pooled age and burn wound percent for the 71 triplicates (n=211 patients) were 55.6±18.3 years and 27.4±22.3% burns. Fifty-seven of 69 (83%) patients had inhalation injuries and 54 of 69 (78%) patients survived. Nebulizations averaged 6.8±3.3 days (range 3-12 days). Serum creatinine rose in 2 patients receiving colistimethate nebulizations, known to cause nephrotoxicity following nebulization. Triplicate comparisons via ANOVA noted prolonged ventilatory support (F=13.39; p≪0.05) and length of stay (F=6.11; p≪0.5). Variance was attributed to the sicker nebulized patients. Twenty-four inhalation injury-only triplicates further confirmed that nebulized patient subgroup was more ill. CONCLUSION: Short duration antibiotic nebulization may allow higher intra-tracheal antibiotic concentrations and may facilitate weaning from the ventilator by reducing bacterial bioburden.

Burn center management of operating room fire injuries.

Approximately 100 operating room (OR) fires occur per year in the United States, with 15% resulting in serious injuries. Intraoperative cautery was frequently associated with OR fires before 1994; however, use of supplemental oxygen (O(2)), ethanol-based products, and disposable drapes have been more frequently associated with OR fires. Fires resulting from cosmetic and other small procedures involving use of nasal canula O(2) and electrocautery have been described in six published reports. We report five thermal injury cases admitted to our burn treatment center because of fires during surgical procedures over a 5-year period. Two patients undergoing supraorbital excision experienced 2.5 and 3% TBSA involvement burns; in a third patient surgical excision of a nasal polyp resulted in a 1% TBSA burn; in a fourth patient an excisional biopsy of a lymph node resulted in a 2.75% TBSA burn; and the last patient was burned during placement of a pacemaker, with resulting TBSA of 10.5%. Two of the five patients required intubation for inhalational injury. Two patients required tangential excision and grafting of their thermal injuries. All patients had received local or parenteral anesthesia with supplemental O(2)/nitrous oxide (N(2)O) for surgical procedure. There are a number of ignition sources in the OR, including electrocautery, lasers, and faulty OR equipment. The risk of OR fires increases with surgical procedures involving the face and neck, including tracheostomy and tracheobronchial surgery. The common use of O(2)/N(2)O mixtures or enriched O(2) for minimally complex surgical procedures and disposable drapes adds to the risk of an OR fire: the O(2)/N(2)O provides a fuel source, and the disposable drapes trap thedelivered gas. Electrocautery near an O(2)/N(2)O source resulted in the five thermal injuries and warrants careful reconsideration of technique for surgical procedures.

Amlodipine-induced toxic epidermal necrolysis.

The objective of this study is to report a case of amlodipine-induced dermatotoxicity following treatment for diabetic nephropathy. Although other members of the dihydropyridine calcium channel blockers have been reported to cause dermatotoxic reactions, this is the first report attributing this effect to amlodipine. A 71-year-old diabetic and hypertensive woman had been noted to have worsened renal dysfunction and hyperkalemia attributed to enalapril, thus a trial of amlodipine was begun. On day 12 of amlodipine therapy, the patient developed a pruritic maculopapular rash on her hands for which she sought medical attention. On day 16, she presented again to the emergency department now with hives and small blisters involving the trunk and arms with ∼25% TBSA involvement warranting transfer to a regional burn treatment center. The rash progressed after admission to 48.5% TBSA and included conjunctival sloughing. The patient's hospital course was uneventful, and she was discharged after 8 days. Drug-induced dermatotoxicity presenting as toxic epidermal necrolysis is often caused by antibiotics and antiepileptic medications; however, calcium channel blockers are an uncommon cause. The Naranjo assessment yielded a score of 5, and the SCORTEN was 4 with a predicted mortality of 58%. This report represents the first published case of amlodipine-induced toxic epidermal necrolysis.