Therapeutic targets in necrotizing soft tissue infections

Contribution of Topical Agents such as Hyaluronic Acid and Silver Sulfadiazine to Wound Healing and Management of Bacterial Biofilm

Background and Objectives: Wound healing is commonly associated with critical bacterial colonization or bacterial infection, which induces prolonged inflammation, resulting in delayed re-epithelialization. An appropriate wound dressing requires a humid environment, which also functions as a barrier against bacterial contamination and will accelerate a regenerative response of the wound. Silver sulfadiazine (SSD) is used to prevent wound infection. Hyaluronic acid (HA) is an extracellular matrix component involved in tissue regeneration. This retrospective study was conducted to evaluate the effectiveness of cream and gauze pads based on hyaluronic acid at low molecular weight (200 kDa) and silver sulfadiazine 1% in the wound healing process. In addition, we examined SSD action on biofilms in vitro and on animal wounds, obtaining positive outcomes therefrom. Materials and Methods: We selected 80 patients with complicated chronic wounds of different etiologies, including diabetes mellitus (10), post-traumatic ulcers (45), burns (15), and superficial abrasion (10). Results: After 8 weeks, ulcer size was decreased in 95 ± 2% of the treated patients; a significant reduction in the inflammatory process was observed from day 14 onwards (p < 0.01 vs. baseline), considering improvement of the surrounding skin and reduction of the bacterial load. The SSD treatment decreased bacterial colony proliferation, both in planktonic state and in biofilm, in a dose-dependent manner on the wound but inhibited the development of tissue granulation at the highest dose (800 μg/wound). Conclusions: In conclusion, the combined action of SSD and HA is clinically effective in improving wound healing.

Duration of Antibiotic Therapy in Necrotizing Soft Tissue Infections: Shorter is Safe

Background: Early debridement improves outcome in necrotizing soft tissue infection (NSTI), but there is no consensus on duration of antimicrobial therapy. We recently changed practice to discontinue antibiotic agents early with a goal of 48 hours after adequate source control. We hypothesized that discontinuing antibiotic agents after a short course is safe in the treatment of NSTI. Patients and Methods: This was a prospective study of patients with NSTI comparing short duration of antibiotic agents to a control population after a change in practice. In 2018 we began discontinuing antibiotic agents within 48 hours of source control (absence of cellulitis and no evidence of active infection). Previously, antibiotic duration was at the discretion of the attending surgeon (generally 7-10 days). Patients were excluded from analysis if they were initially debrided at a referring facility, immune compromised, or died prior to source control. Patient characteristics and outcomes were evaluated. The primary outcome was treatment failure requiring antibiotic agents to be restarted with or without further debridement of infected tissue. Secondary outcomes included the duration of antibiotic therapy after source control. Results: We evaluated 151 patients; 119 admitted between January 1, 2011 and January 31, 2018 (PRE) and 32 admitted after January 31, 2018 (POST). Patients were not statistically different regarding characteristics, admission physiologic variables, and comorbidities. The median duration of antibiotic agents after source control in the PRE group was 180.3 hours (interquartile range [IQR], 100.7-318.8) versus 48 hours (IQR, 32.3-100.8) in the POST group (p < 0.01). Patients in each group were treated as described above, and treatment failure occurred in seven (5.9%) PRE patients and two (6.3%) POST (99.3% post hoc power at non-inferiority limit 20%, significance p < 0.05). Thirty-day all-cause mortality was not different between groups (6.7% vs. 6.3%; p = 0.94). Conclusions: Short-duration (48 hours) antibiotic agents after NSTI source control is as safe and effective as a longer course.

Necrotizing Fasciitis: A Life-Threatening Infection Due to Clostridium Species

Necrotizing fasciitis (NF), soft tissue infections, are rare but rapidly progressive and life-threatening infections with high morbidity and mortality rates. Early detection and intervention by physicians are paramount in mortality prevention. We present a case report of a 77-year-old female who presented with extensive NF due to a Clostridium septicum infection.

Necrotizing soft tissue infection: clinical characteristics, diagnosis, and management of 32 cases in Beijing

OBJECTIVE

Necrotizing soft tissue infection (NSTI) is a rare but life-threatening bacterial infection. This study was performed to analyze the clinical characteristics of patients with NSTI admitted to the intensive care unit of a trauma and burn center in Beijing and to summarize the treatment experience.

METHODS

This retrospective study involved patients with NSTI admitted to the intensive care unit from January 2010 to January 2020. The clinical manifestations, pathogens, laboratory test results, and prognosis were compared between survivors and nonsurvivors.

RESULTS

Thirty-two patients were enrolled (28 men, 4 women), including 25 (78.1%) survivors and 7 (21.9%) nonsurvivors. The patients' median age was 41.5 years (range, 30.0-52.5 years). Mortality was significantly higher in patients with a blood urea nitrogen concentration of ≥11.5 mg/dL, creatinine concentration of <3.4 mg/dL, prothrombin time of ≥15.9 s, and international normalized ratio of ≥1.3. Streptococcus pyogenes and Clostridium perfringens infections were associated with higher mortality.

CONCLUSIONS

More attention should be given to elderly patients and those with hyponatremia, coagulation disorder, and higher blood urea nitrogen or creatinine concentrations. The finding of large gram-positive rods or large numbers of gram-positive cocci in wound secretion smears is a helpful early warning sign of highly lethal NSTI.

Dynamic Changes in Microbial Composition During Necrotizing Soft-Tissue Infections in ICU Patients

Introduction: Recent studies described the threat of emerging multidrug-resistant (MDR) bacteria in intensive care unit (ICU) patients, but few data are available for necrotizing skin and soft tissue infections (NSTI). In a cohort of ICU patients admitted for NSTI, we describe the dynamic changes of microbial population during repeated surgeries.

Materials and Methods: This retrospective study compiled consecutive cases admitted for the management of severe NSTI. Clinical characteristics, NSTI features, morbidity and mortality data were collected. The microbiological characteristics of surgical samples obtained during initial surgery were compared with those obtained during the first reoperation, including persistence of initial pathogens and/or emergence of microorganisms. Risk factors for emergence of microorganisms and MDR bacteria were assessed by univariable and multivariable analyses.

Results: Among 100 patients {63% male, 58 years old [interquartile ratio (IQR) 50–68]} admitted for NSTI, 54 underwent reoperation with a median [IQR] delay of 3 (1–7) days. Decreased proportions of susceptible strains and emergence of Gram-negative bacteria, including Pseudomonas aeruginosa, staphylococci and enterococci strains, were reported based on the cultures of surgical specimen collected on reoperation. On reoperation, 22 (27%) of the isolated strains were MDR (p < 0.0001 vs. MDR bacteria cultured from the first samples). Broad-spectrum antibiotic therapy as first-line therapy was significantly associated with a decreased emergence of microorganisms. Adequate antibiotic therapy from the initial surgery did not modify the frequency of emergence of microorganisms (p = 0.79) and MDR bacteria (p = 1.0) or the 1-year survival rate.

Conclusion: The emergence of microorganisms, including MDR bacteria, is frequently noted in NSTI without affecting mortality.

Intensive multidisciplinary management in critical care patients affected by severe necrotizing soft tissue infections: a cooperative method to improve the efficacy of treatment

To illustrate the effectiveness of our intensive multidisciplinary management (IMM) in the treatment of severely ill patients with necrotizing soft tissue infections (NSTIs). A retrospective observational study was conducted in a general ICU. Thirty-two consecutive patients undergoing IMM were carefully compared with 30 consecutive patients receiving a standard management (SM). IMM combined intensive care management, early surgical debridement followed by daily inspection of surgical wounds, close microbiological surveillance, and targeted high-dose antibiotics. IMM was associated with the better decrease of daily SOFA score (p = 0.04). Also, IMM caused + 12% increase in the overall number of surgical procedures (p = 0.022) and a higher number of tissue biopsies/per day (median 0.63 versus 0.32; p = 0.025), leading to a more targeted antimicrobial changes (89.6% vs 51.6%; p < 0.00001). High-dose daptomycin (75% vs 36.7%; p = 0.002) and extended/continuous infusion of beta-lactams (75% vs 43.3%; p = 0.011) were more frequently utilized. A specific efficiency score correlated with the decrease of SOFA score (efficacy) in IMM patients only (p = 0.027). Finally, IMM was associated with a significant lower ICU mortality rate (15.6% vs 40%; p = 0.032). IMM was more effective than SM as it allowed the earlier control of infection and the faster reduction of multiple organ-dysfunction.