[DYNAMICS OF BACTERIOLOGICAL AND PLANIMETRIC INDICES OF THE WOUND UNDER THE ACTION OF THE SILVER NANOPARTICLES, STABILIZED BY MEXIDOL AND POLYVINYLPYRROLIDONE]

Changes in bacteriological indices through the square of the wound of chemical origin under local impact of the silver nanoparticles (NP), stabilized by 2-ethyl-6-methyl-3-hydroxypyridine succinate (mexidol) and polyvinylpyrrolidone were studied. The wounds of submandibular region were simulated in white rats, using injection of 10% solution of calcium chloride with further opening of necrotic foci and open management of the wound. Beginning from the fifth day, every day the wound was irrigated with liquid, which have contented the stabilized NP of the silver, 0.05% water solution of chlorhexidine or isotonic solution of the the sodium chloride (control). There was established, that the silver NP impact antiseptically and regenerative while the wound treatment, and reduce during 10 days microbial contamination of exudate in 24 times, the wound square--in three times in comparison with original indices. These changes were identical to those while application of chlorhexidine.

Type I Interferon Signaling Prevents IL-1β-Driven Lethal Systemic Hyperinflammation during Invasive Bacterial Infection of Soft Tissue

Type I interferons (IFN-Is) are fundamental for antiviral immunity, but their role in bacterial infections is contradictory and incompletely described. Streptococcus pyogenes activates IFN-I production in innate immune cells, and IFN-I receptor 1 (Ifnar1)-deficient mice are highly susceptible to S. pyogenes infection. Here we report that IFN-I signaling protects the host against invasive S. pyogenes infection by restricting inflammation-driven damage in distant tissues. Lethality following infection in Ifnar1-deficient mice is caused by systemically exacerbated levels of the proinflammatory cytokine IL-1β. Critical cellular effectors of IFN-I in vivo are LysM+ and CD11c+ myeloid cells, which exhibit suppression of Il1b transcription upon Ifnar1 engagement. These cells are also the major source of IFN-β, which is significantly induced by S. pyogenes 23S rRNA in an Irf5-dependent manner. Our study establishes IL-1β and IFN-I levels as key homeostatic variables of protective, yet tuned, immune responses against severe invasive bacterial infection.

[The pitfalls of necrotising soft tissue infection: a 'wake-up call' for surgeons]

Necrotising soft tissue infections require early consultation of an experienced surgeon, regardless of what time of day they occur. Delays in diagnosis and treatment should not occur. Necrotectomy should be skin-sparing when possible. A low threshold for consultation with a tertiary referral center is recommended.

Pitfalls in diagnosing diabetic foot infections

Although the diagnosis of a diabetic foot infection is made based on clinical symptoms and signs, we also use blood laboratory, microbiological and radiological studies to make treatment decisions. All of these diagnostic studies have pitfalls that can lead to a delay in diagnosis. Such delays will likely lead to further tissue damage and to a higher chance of amputation. One of these pitfalls is that some clinicians rely on microbiological, rather than clinical data, to diagnose infection. Though subjective by nature, clinical signs predict outcome of foot infections accurately. Another pitfall is that microbiological data can be misleading. All wounds harbour microorganisms; therefore, a positive wound culture does not mean that a wound is infected. Furthermore, the outcome of cultures of wound swabs does not correlate well with culture results of tissue biopsies. Therapy guidance by wound swab will likely lead to overtreatment of non-pathogenic organisms. Genotyping might have a role in identifying previously unrecognized (combinations of) pathogens in diabetic foot infection, bacteria in sessile phenotype and non-culturable pathogens, e.g. in cases where antibiotics have already been administered. One more pitfall is that the diagnosis of osteomyelitis remains difficult. Although the result of percutaneous bone biopsy is the reference standard for osteomyelitis, some other diagnostic modalities can aid in the diagnosis. A combination of several of these diagnostic tests is probably a good strategy to achieve a higher diagnostic accuracy. Relying on a single test will likely lead to misidentification of patients with osteomyelitis with associated overtreatment and undertreatment.

[PROGNOSIS OF INFECTIVE COMPLICATIONS OF THE GUN-SHOT WOUNDS OF SOFT TISSUES]

The method of prognostication of infectious complications in a gun-shot wound was elaborated, using the methods of logistic regression analysis.

Development of a Novel Model for the Assessment of Dead-Space Management in Soft Tissue

Following extensive surgical debridement in the treatment of infection, a “dead space” can result following surgical closure that can fill with hematoma, an environment conducive to bacterial growth. The eradication of dead space is essential in order to prevent recurrent infection. This study describes a novel small animal model to investigate dead-space management in muscle tissue. Two absorbable test materials were implanted in each animal; beads of calcium sulfate alone, and beads loaded with vancomycin and tobramycin. In-life blood samples and radiographs were taken from each animal following implantation. Animals were sacrificed at 1, 7, 21, 42, and 63 days post-operatively (n = 4), and implant sites were analysed by micro-computed tomography, histology and immunohistochemistry. Complete resorption was confirmed radiographically at 3 weeks post-implantation. Histologically, the host tissue response to both materials was identical, and subsequent healing at the implant sites was observed with no dead space remaining. Vancomycin was not detected in blood serum. However, peak tobramycin levels were detected in all animals at 6 hours post-implantation with no detectable levels in any animals at 72 hours post implantation. Serological inflammatory cytokine expression for IL-6, TNF-α and IL-1β indicated no unusual inflammatory response to the implanted materials or surgical procedure. The model was found to be convenient and effective for the assessment of implant materials for management of dead space in muscle tissue. The two materials tested were effective in resolving the surgically created dead space, and did not elicit any unexpected adverse host response.

Subcutaneous Injection of Percocet: A Case of Severe Soft Tissue Loss

Prescription drug abuse ranks as the second most common class of illicit drug use in the United States, and one mechanism of opiate abuse involves intravenous injection of enteral narcotics such as oxycodone or hydrocodone. The authors describe a patient who sustained significant soft tissue necrosis after intravenously injecting a solution made from crushed enteral narcotics, with a focus on the operative course that resulted due to a delay in initial definitive treatment. The patient's wounds encompassed 8% total body surface area and covered 247 cm2. A 55-year-old female was admitted to the burn unit (West Penn Burn Center, Western Pennsylvania Hospital, Pittsburgh, PA) after she initially presented with infection and cellulitis to her bilateral upper extremities 3 weeks after intravenously injecting herself with crushed oxycodone/acetaminophen. She underwent numerous sequential operative repairs including initial debridement, placement of dermal replacement templates, and several split-thickness autografts and xenografts. Her total length of stay was 59 days, broken into an initial 47-day stay, and a subsequent 12-day readmission due to graft failure secondary to poor follow-up. As the number of prescription drug abusers rises, it is possible that an increase in attempts to intravenously abuse enteral narcotics may also rise. As such, burn centers should be prepared for the extent of potential limb necrosis and the operative treatment that may ensue.

Targeting Staphylococcus aureus α-toxin as a novel approach to reduce severity of recurrent skin and soft-tissue infections

Staphyococcus aureus frequently causes recurrent skin and soft-tissue infection (SSTI). In the pediatric population, elevated serum antibody targeting S. aureus α-toxin is correlated with a reduced incidence of recurrent SSTI. Using a novel model of recurrent SSTI, we demonstrated that expression of α-toxin during primary infection increases the severity of recurrent disease. Antagonism of α-toxin by either a dominant-negative toxin mutant or a small molecule inhibitor of the toxin receptor ADAM10 during primary infection reduces reinfection abscess severity. Early neutralization of α-toxin activity during S. aureus SSTI therefore offers a new therapeutic strategy to mitigate primary and recurrent disease.

A novel mouse model of soft-tissue infection using bioluminescence imaging allows noninvasive, real-time monitoring of bacterial growth

Musculoskeletal infections, including surgical-site and implant-associated infections, often cause progressive inflammation and destroy areas of the soft tissue. Treating infections, especially those caused by multi-antibiotic resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA) remains a challenge. Although there are a few animal models that enable the quantitative evaluation of infection in soft tissues, these models are not always reproducible or sustainable. Here, we successfully established a real-time, in vivo, quantitative mouse model of soft-tissue infection in the superficial gluteus muscle (SGM) using bioluminescence imaging. A bioluminescent strain of MRSA was inoculated into the SGM of BALB/c adult male mice, followed by sequential measurement of bacterial photon intensity and serological and histological analyses of the mice. The mean photon intensity in the mice peaked immediately after inoculation and remained stable until day 28. The serum levels of interleukin-6, interleukin-1 and C-reactive protein at 12 hours after inoculation were significantly higher than those prior to inoculation, and the C-reactive protein remained significantly elevated until day 21. Histological analyses showed marked neutrophil infiltration and abscesses containing necrotic and fibrous tissues in the SGM. With this SGM mouse model, we successfully visualized and quantified stable bacterial growth over an extended period of time with bioluminescence imaging, which allowed us to monitor the process of infection without euthanizing the experimental animals. This model is applicable to in vivo evaluations of the long-term efficacy of novel antibiotics or antibacterial implants.

[Frequency of diseases caused by group A streptococci among invasive infections of soft tissues and characteristics of the causative agent]

AIM

Determine frequency of diseases caused by group A streptococci (GAS) among invasive infections of soft tissues; identify emm-types of the isolated streptococci, determine the presence of bacteriophage integrases and toxin genes in their genomes.

MATERIALS AND METHODS

4750 case histories of patients with soft tissue infections of the purulent-surgical department of the 23rd City Clinical Hospital.of Moscow "Medsantrud" in 2008 - 2011 were analyzed. 46 strains of GAS isolated from patients with invasive streptococcus infection (ISI) were studied. GAS identification was carried out by latex-agglutination method. GAS emm-type was determined by molecular-genetic methods, as well as the presence of bacteriophage integrases int2, int3, int4, int5, int6, int7, int49, bacteriophage toxins speA, speI, sla, speC/J, speL, speH, speC, ssa and speB gene present on the chromosomal DNA.

RESULTS

132 cases (2.8%) were attributed to invasive infections. In 46 cases of invasive infections (35%) GAS were isolated. 22 different emm-types of invasive GAS strains were detected. Only speB gene among all the toxin genes (as well as the expression of the gene--SpeB toxin) was detected in all the strains, whereas sla and speI genes were not detected in any of the strains. Genes of the other toxins (ssa, speL, speC, speA, speH, speC/J) occurred in a number of strains. Genes of phage integrases were detected among all the strains however in varying combinations (from 1 to 4 genes).

CONCLUSION

Invasive infections caused by GAS are more frequently spread than had been previously assumed and a high degree of genetic heterogeneity of invasive GAS strains was detected.

[Expedience of application of a dietic therapy in treatment of purulent-septic diseases of soft tissues]

The results of investigation of the dietotherapy impact on the course of purulent-septic process in soft tissues were analyzed. There were operated 58 patients, to 38 of them a certain diet was prescribed. Immediate impact of the diet therapy on the wound process course was established, what was demonstrated by reduction of duration of the earning capacity loss in patients, who have followed a special diet, by 2.58 days.

Vacuum-assisted therapy accelerates wound healing in necrotizing soft tissue infections: our experience in two intravenous drug abuse patients

Negative pressure wound therapy using vacuum-assisted closure (VAC) devices is currently a well established technique for managing complicated wounds. Such wounds occur after aggressive surgical debridement for necrotizing soft tissue infections (NSTI). In this report we present our experience in two intravenous drug abusers managed with VAC for NSTIs. The patients were 25 and 34 years old, HCV positive and presented with oedema of the upper femoral compartments and concomitant severe sepsis. Ultrasonography and computed tomography revealed severe cellulitis, fluid collection and necrosis of the affected fasciae and muscles. After emergent and subsequent aggressive surgical debridement during the first 48h, the VAC device was applied. Both patients had an uncomplicated postoperative course and a fast recovery from their multiorgan dysfunction. Suture closure of the wounds was achieved at the 25th and 38th postoperative days respectively and patients were discharged without any motor deficit. Negative pressure wound therapy is a modern therapeutic modality for treating complicated infected wounds. Moreover, it accelerates wound healing and primary closure, facilitating patient ambulation and recovery. A dedicated medical and nursing team is an important prerequisite for a successful outcome.

Acute focal bacterial nephritis due to methicillin-resistant Staphylococcus aureus in an immunocompetent adult

Acute focal bacterial nephritis (AFBN) is a rare, acute focal infection of the renal parenchyma without liquefaction. The pathogenesis is thought to be due to hematogenous infection or ascending infection from the lower urinary tract. Escherichia coli has been the major pathogen isolated in prior cases, but other Gram-negative enteric pathogens and Staphylococcus aureus have been reported as well. It is well described in children and adults with diabetes and organ transplantation, but has not been previously reported in healthy adults. We report a case of an immunocompetent adult female who presented with a methicillin-resistant Staphylococcus aureus bacteremia after a skin and soft tissue infection that resulted in AFBN.

Timing of redébridement after initial source control impacts survival in necrotizing soft tissue infection

Necrotizing soft tissue infections (NSTIs) are associated with a high mortality rate. There is a lack of literature examining outcomes in NSTI when surgical redébridements are performed in early versus delayed intervals. We hypothesized that early redébridement is associated with improved survival. Patients with NSTIs were prospectively enrolled between January 2006 and December 2011. Patient demographics, comorbidities, primary infection site, laboratory values, tissue cultures, time to surgery, and time between subsequent débridements were obtained. Two study groups with divergent redébridement protocols were observed: a short interval redébridement (SIRD) and an extended interval redébridement (EIRD). Univariate and multivariate statistics were performed. The primary outcome evaluated was in-hospital mortality. Sixty-four patients (46 SIRD, 18 EIRD) were included in the analysis. The two groups had comparable demographics. Polymicrobial NSTI was noted in 61 per cent of patients with Staphylococcus species being the predominant causative organism (59%). Multivariate analysis showed the EIRD protocol to be associated with a significantly increased incidence of acute kidney injury (adjusted odds ratio, 4.9 [1.1 to 22.5]; P = 0.04) and worse overall survival (hazard ratio, 10.6 [2.1 to 53.9]; P = 0.004). Delayed redébridement after initial source control in NSTIs results in worse survival and an increased incidence of acute kidney injury. Further studies to identify the optimal time interval for redébridement are warranted.

Necrotizing soft tissue infections (NSTIs): literary review and description of a Fournier syndrome case

A 62 y.o. male with tight fimosis, swelling, redness, pain on palpating and necrosis of the penis and scrotum was admitted in our clinic, (FGSI = 6) with periferic vasculopathy; and diabetes mellitus type II and he was in dialysis treatment before the hospitalization. The patient was HCV affected. In 24 hours he underwent radical surgical debridement with excision of all necrotic material from penis and scrotum up to the subdermal layer and tissue of doubtful viability for about 75% of the skin and circumcision. In third, fifth and seventh postoperative days he underwent to local infusion of autologous PLT growth factors. The patient was discharged in 9th postoperative day and FGSI was still 6; the skin and subdermal tissue was barely reskined, with low homogeneous granulation, edema was heavely reduced. In our case, deviation from homeostasis status at admission was the main worrying factor. We found that diabetes mellitus and renal dysfunction at admission was also important risk factor for FG. "E.Coli" was the most common organism isolated from patient wound cultures. The FGSI is an objective and easy to apply score method to quantify the metabolic status and can be used to evaluate therapeutic options and assess results.

[Treatment of patients with purulent wounds by using the original method of hydrodynamical drainage]

In this article the work of the Omsk State Medical Academy's department of general surgery is presented. The aim of study was to treat patients with purulent and necrotic wounds of soft tissue by using novel hydrodynamical drainaige. In this research 92 patients were taken part, who were inpatient treatment in the department of purulent surgery City Clinical Hospital No 1 named Kabanov A. N. 2010-2013 with purulent and necrotic wounds of soft tissue. Clinical, laboratory, cytological, bacteriological monitoring were conducted over the of wound process during the treatment. Assessment of the reliability of differences between the mean value of clinical indicators was with the calculation of the criterion t--Student, the method chi2 and Criterion Mann-Whitney U. The proposed method of treatment of purulent wound promotes fast the removal of necrotic tissue and pus in the first phase of the wound process that led to more rapid relief of symptoms of intoxication (fever, leukocytosis and common symptoms) at the patients of the basic group. Due to faster removal of necrotic tissue, reduction of common symptoms of intoxication at the patients of the basic group the transition from degenerative and inflammatory type of cystograms to regenerative occurred one or two days before than in the comparison group.

Magnetic resonance imaging of soft tissue infection with iron oxide labeled granulocytes in a rat model

OBJECT

We sought to detect an acute soft tissue infection in rats by magnetic resonance imaging (MRI) using granulocytes, previously labeled with superparamagnetic particles of iron oxide (SPIO).

MATERIALS AND METHODS

Parasternal infection was induced by subcutaneous inoculation of Staphylococcus aureus suspension in rats. Granulocytes isolated from isogenic donor rats were labeled with SPIO. Infected rats were imaged by MRI before, 6 and 12 hours after intravenous injection of SPIO-labeled or unlabeled granulocytes. MR findings were correlated with histological analysis by Prussian blue staining and with re-isolated SPIO-labeled granulocytes from the infectious area by magnetic cell separation.

RESULTS

Susceptibility effects were present in infected sites on post-contrast T2*-weighted MR images in all animals of the experimental group. Regions of decreased signal intensity (SI) in MRI were detected at 6 hours after granulocyte administration and were more pronounced at 12 hours. SPIO-labeled granulocytes were identified by Prussian blue staining in the infected tissue and could be successfully re-isolated from the infected area by magnetic cell separation.

CONCLUSION

The application of SPIO-labeled granulocytes in MRI offers new perspectives in diagnostic specificity and sensitifity to detect early infectious processes.

Necrotizing soft-tissue infections

NSTI is a life-threatening, surgical, and medical emergency. Clinical presentation, at least in the initial phase, can be misleading. Various studies have shown that delay in surgical debridement is associated with increased mortality. A high index of suspicion is important in early recognition and in instituting prompt therapy without delay. Early diagnosis, aggressive surgical debridement, aggressive supportive care, and optimal presumptive antibiotic therapy significantly improve morbidity and mortality associated with NSTIs.

ACTINOMYCOSIS INFECTION OF THE FINGER

Actinomycosis is a rare cause of infection in the hand. We report a case of actinomycosis infection involving proximal phalanx, with the clinical presentation mimicking that of a bony neoplasm.

Septic shock, pneumonia, and soft tissue infection due to Myroides odoratimimus: report of a case and review of Myroides infections

The genus Myroides comprises aerobic, yellow-pigmented, non-motile, non-fermenting gram-negative rods formerly classified as Flavobacterium odoratum. Members of the genus are widely distributed in the environment, especially in water, and usually behave as low-grade opportunistic pathogens, having been found to cause urinary tract infection, endocarditis, ventriculitis, and cutaneous infections in severely immunocompromised patients. We report a case of soft tissue infection, septic shock, and pneumonia due to M. odoratimimus in an immunocompetent male. To our knowledge, this is the first description of life-threatening infection caused by this organism in an immunocompetent host. We have also reviewed the medical literature on the genus Myroides.

[Experimental study of combination of ciprofloxacin and oxytocin on formation of biofilms by opportunistic bacteria]

AIM

To study in vitro and in vivo effect of oxytocin and ciprofloxacin combination on formation of biofilms by agents of surgical infections.

MATERIALS AND METHODS

Microorganisms of different species isolated by conventional methods from patients with purulent soft tissue infections were used in experiments. Ciprofloxacin manufactured by "Dr. Reddys" (India) and oxytocin manufactured by "Gedeon Richter" (Hungary) were used. For in vitro experiments one-half of minimal inhibitory concentrations of drugs were used. Oxytocin-placebo ("Gedeon Richter", Hungary) was used for control tests. Formation of biofilms was assessed using method proposed by G. O'Toole (2000). For in vivo experiments septic wounds in 1st phase of wound process were modeled according to method proposed by E.M. Danilova (1992). Wounds were infected with Staphylococcus aureus strain 104, which has strong ability to form biofilms. Efficacy of treatment was assessed on signs of inflammatory process and microscopy of touch smears for detection of bacterial biofilms.

RESULTS

In experiments in vivo addition of oxytocin to nutrient medium resulted in suppression of biofilm formation by studied microorganisms. Obtained data were confirmed by in vivo experiments which demonstrated higher efficacy of local application of ciprofloxacin and oxytocin combination for treatment of septic wounds compared to separate use of ciprofloxacin or oxytocin.

CONCLUSION

Studies performed in vitro and in vivo showed efficacy of oxytocin and ciprofloxacin combination, which is determined not only by enhancement of antimicrobial effect of the drug against pathogen but also by suppression of biofilm formation in the wound during infection.

The use of drotrecogin alpha for necrotizing soft tissue infections

The use of Drotrecogin alfa (DAA) (Xigris) in select patients with sepsis has had demonstrable improvement in survival, though its benefit in necrotizing soft tissue infections (NSTI) is unclear. A retrospective review of NSTI patients receiving DAA at our institution from 2006 to 2009 was performed. Our previously derived mortality prediction model, based on classification and regression tree analysis, was applied to patients and the predicted mortality was compared with the actual mortality rate. Ten patients with severe NSTI received DAA. The median admission values were: white blood cell count of 27,000/mm3, serum lactate of 4.0 mmol/L, and serum sodium of 128 mEq/L. Four (40%) patients had systemic complications, five (50%) patients required amputation, and one died (10%). Median time to DAA administration was 12 hours after debridement. There were no bleeding complications attributed to DAA use. Mortality in this series of severe NSTI was only 10 per cent, which compares favorably with the predicted mortality of 18 per cent based on classification and regression tree analysis (P = 0.2). A prospective, randomized study is warranted to determine if the use of DAA should be part of the standard therapy for NSTI patients with a predicted high mortality.