A Structured Approach to Skin and Soft Tissue Infections (SSTIs) in an Ambulatory Setting

Nanosecond pulsed electric fields increase antibiotic susceptibility in methicillin-resistant Staphylococcus aureus

IMPORTANCE

We have found that treatment with short electric pulses potentiates the effects of multiple antibiotics against methicillin-resistant Staphylococcus aureus. By reducing the dose of antibiotic necessary to be effective, co-treatment with electric pulses could amplify the effects of standard antibiotic dosing to treat S. aureus infections such as skin and soft-tissue infections (SSTIs). SSTIs are accessible to physical intervention and are good candidates for electric pulse co-treatment, which could be adopted as a step-in wound and abscess debridement.

Assessment of antibiotic release and antibacterial efficacy from pendant glutathione hydrogels using ex vivo porcine skin

Acute bacterial skin and skin structure infections (ABSSSIs) confer a substantial burden on the healthcare system. Local antibiotic delivery systems can provide controlled drug release directly to the site of infection to maximize efficacy and minimize systemic toxicity. The purpose of this study was to examine the antibacterial activity of antibiotic-loaded glutathione-conjugated poly(ethylene glycol) hydrogels (GSH-PEG) against ABSSSIs utilizing an ex vivo porcine dermal explant model. Vancomycin- or meropenem-loaded GSH-PEG hydrogels at 3 different dose levels were loaded over 1 h. Drug release was monitored in vitro under submerged conditions, by the Franz cell diffusion method, and ex vivo utilizing a porcine dermis model. Antibacterial activity was assessed ex vivo on porcine dermis explants inoculated with Staphylococcus aureus or Pseudomonas aeruginosa isolates treated with vancomycin- or meropenem-loaded GSH-PEG hydrogels, respectively. Histological assessment of the explants was conducted to evaluate tissue integrity and viability in the context of the experimental conditions. A dose-dependent release was observed from vancomycin and meropenem hydrogels, with in vitro Franz cell diffusion data closely representing ex vivo vancomycin release, but not high dose meropenem release. High dose vancomycin-loaded hydrogels resulted in a >3 log10 clearance against all S. aureus isolates at 48 h. High dose meropenem-loaded hydrogels achieved 6.5, 4, and 2 log10 reductions in CFU/ml against susceptible, intermediate, and resistant P. aeruginosa isolates, respectively. Our findings demonstrate the potential application of GSH-PEG hydrogels for flexible, local antibiotic delivery against bacterial skin infections.

Azithromycin-loaded liposomal hydrogel: a step forward for enhanced treatment of MRSA-related skin infections

Azithromycin (AZT) encapsulated into various types of liposomes (AZT-liposomes) displayed pronounced in vitro activity against methicillin-resistant Staphylococcus aureus (MRSA) (1). The present study represents a follow-up to this previous work, attempting to further explore the anti-MRSA potential of AZT-liposomes when incorporated into chitosan hydrogel (CHG). Incorporation of AZT-liposomes into CHG (liposomal CHGs) was intended to ensure proper viscosity and texture properties of the formulation, modification of antibiotic release, and enhanced antibacterial activity, aiming to upgrade the therapeutical potential of AZT-liposomes in localized treatment of MRSA-related skin infections. Four different liposomal CHGs were evaluated and compared on the grounds of antibacterial activity against MRSA, AZT release profiles, cytotoxicity, as well as texture, and rheological properties. To our knowledge, this study is the first to investigate the potential of liposomal CHGs for the topical localized treatment of MRSA-related skin infections. CHG ensured proper viscoelastic and texture properties to achieve prolonged retention and prolonged release of AZT at the application site, which resulted in a boosted anti-MRSA effect of the entrapped AZT-liposomes. With respect to anti-MRSA activity and biocompatibility, formulation CATL-CHG (cationic liposomes in CHG) is considered to be the most promising formulation for the treatment of MRSA-related skin infections.

Skin and soft tissue infection incidence before and during the COVID-19 pandemic

Skin and Soft Tissue Infections (SSTIs) are common bacterial infections. We hypothesized that due to the COVID-19 pandemic, SSTI rates would significantly decrease due to directives to avoid unneeded care and attenuated SSTIs risk behaviours. We retrospectively examined all patients with an ICD-10 diagnosis code in the Los Angeles County Department of Health Services, the second largest U.S. safety net healthcare system between 16 March 2017 and 15 March 2022. We then compared pre-pandemic with intra-pandemic SSTI rates using an interrupted time series analysis. We found 72,118 SSTIs, 46,206 during the pre-pandemic period and 25,912 during the intra-pandemic period. Pre-pandemic SSTI rate was significantly higher than the intra-pandemic rate (3.27 vs. 2.31 cases per 1,000 empanelled patient-months, P < 0.0001). The monthly SSTI cases decreased by 1.19 SSTIs/1,000 empanelled patient-months between the pre- and intra-pandemic periods (P = 0.0003). SSTI subgroups (inpatient, observation unit, emergency department, and outpatient clinics), all had significant SSTI decreases between the two time periods (P < 0.05) except for observation unit (P = 0.50). Compared to the pre-COVID-19 pandemic period, medically attended SSTI rates in our large U.S. safety net healthcare system significantly decreased by nearly 30%. Whether findings reflect true SSTI decreases or decreased health system utilization for SSTIs requires further examination.

Bacterial isolates and their antimicrobial susceptibility profile of superficial and deep-seated skin and soft tissue infections

Background

Skin and soft tissue infections (SSTIs) are caused by microbial invasion of healthy or damaged skin. SSTIs are difficult to manage and contribute to chronicity and emergence of antimicrobial resistance.

Objectives

To ascertain the prevalence of bacteria causing SSTIs and their antimicrobial susceptibility patterns.

Methods

A prospective study between November 2020 and May 2021. A total of 447 samples from SSTIs were analyzed.

Results

A total of 347 samples revealed mono-bacterial growth, of which 67% were male. SSTIs are common among patients aged 21-50 years with the dominance (78%) of gram-negative rods (GNRs). Escherichia coli (36%), Klebsiella spp. (22%), Staphylococcus aureus (16%), and Pseudomonas aeruginosa (11%) were predominant organisms. GNRs were highly resistant (>65%) to ciprofloxacin and trimethoprim-sulfamethoxazole. For injectable antibiotics, the highest resistance was determined against ceftriaxone, and the least resistance was determined against amikacin. Resistance against carbapenem was the highest among P. aeruginosa (53%) and Klebsiella spp. (32%). S. aureus showed the highest resistance against ciprofloxacin, and the least resistance was determined against clindamycin. Of 57 S. aureus isolates, 86% isolates were methicillin-resistant Staphylococcus aureus (MRSA). All isolates of P. aeruginosa and S. aureus were sensitive to polymyxin B and vancomycin, respectively. The prevalence of multidrug-resistant E. coli and Klebsiella spp. was higher among deep-seated SSTIs (dSSTIs).

Conclusions

The predominant etiology of SSTIs is GNR. Currently, there is very high resistance against oral antibiotics. Antimicrobial resistance against carbapenem has also increased. Moreover, there is a high frequency of MRSA. MDR E. coli and Klebsiella spp. isolates are frequently involved in dSSTIs.

A Comprehensive Review on Bio-Based Materials for Chronic Diabetic Wounds

Globally, millions of people suffer from poor wound healing, which is associated with higher mortality rates and higher healthcare costs. There are several factors that can complicate the healing process of wounds, including inadequate conditions for cell migration, proliferation, and angiogenesis, microbial infections, and prolonged inflammatory responses. Current therapeutic methods have not yet been able to resolve several primary problems; therefore, their effectiveness is limited. As a result of their remarkable properties, bio-based materials have been demonstrated to have a significant impact on wound healing in recent years. In the wound microenvironment, bio-based materials can stimulate numerous cellular and molecular processes that may enhance healing by inhibiting the growth of pathogens, preventing inflammation, and stimulating angiogenesis, potentially converting a non-healing environment to an appropriately healing one. The aim of this present review article is to provide an overview of the mechanisms underlying wound healing and its pathophysiology. The development of bio-based nanomaterials for chronic diabetic wounds as well as novel methodologies for stimulating wound healing mechanisms are also discussed.

Clinics and Practice: A Rapidly Developing Journal

Recently, MDPI has acquired a new journal, Clinics and Practice, and started its development [...].

Lymph-derived chemokines direct early neutrophil infiltration in the lymph nodes upon Staphylococcus aureus skin infection

A large number of neutrophils infiltrate the lymph node (LN) within 4 h after Staphylococcus aureus skin infection (4 h postinfection [hpi]) and prevent systemic S. aureus dissemination. It is not clear how infection in the skin can remotely and effectively recruit neutrophils to the LN. Here, we found that lymphatic vessel occlusion substantially reduced neutrophil recruitment to the LN. Lymphatic vessels effectively transported bacteria and proinflammatory chemokines (i.e., Chemokine [C-X-C motif] motif 1 [CXCL1] and CXCL2) to the LN. However, in the absence of lymph flow, S. aureus alone in the LN was insufficient to recruit neutrophils to the LN at 4 hpi. Instead, lymph flow facilitated the earliest neutrophil recruitment to the LN by delivering chemokines (i.e., CXCL1, CXCL2) from the site of infection. Lymphatic dysfunction is often found during inflammation. During oxazolone (OX)-induced skin inflammation, CXCL1/2 in the LN was reduced after infection. The interrupted LN conduits further disrupted the flow of lymph and impeded its communication with high endothelial venules (HEVs), resulting in impaired neutrophil migration. The impaired neutrophil interaction with bacteria contributed to persistent infection in the LN. Our studies showed that both the flow of lymph from lymphatic vessels to the LN and the distribution of lymph in the LN are critical to ensure optimal neutrophil migration and timely innate immune protection in S. aureus infection.

Analysis of Types of Skin Lesions and Diseases in Everyday Infectious Disease Practice-How Experienced Are We?

Rashes and skin lesions are a common reason for patient visits to emergency departments and physicians’ offices. The differential diagnosis includes a variety of infectious and non-infectious diseases, some of which can be life-threatening. The aim of this retrospective study was to evaluate the quantity and type of skin lesions among outpatients and inpatients at a tertiary care university-affiliated teaching hospital for infectious diseases over a three-year period to assess disease burden and physicians’ experience in diagnosing skin lesions. Diagnoses (by ICD-10 codes) were classified into three groups: infectious diseases that include skin lesions, non-infectious skin lesions and undiagnosed skin lesions. During the observed period, out of the total of 142,416 outpatients, 14.8% presented with some form of skin lesion. Among them, 68% had skin lesions inherent to infectious disease, 10.8% suffered from non-infectious skin lesions and 21.2% remained with undiagnosed skin lesions. The most common infectious diagnoses were chickenpox, herpes zoster and unspecified viral infections characterized by skin and mucous membrane lesions. The most common non-infectious diagnoses were urticaria and atopic dermatitis. Overall, the most common individual diagnosis (ICD-10 code) was “nonspecific skin eruption” (n = 4448, 21.1%), which was followed by chickenpox and herpes zoster. Among the 17,401 patients hospitalized over the observed period, 13.1% had skin lesion as the main reason for hospitalization, almost all (97.5%) of which were infectious in etiology. The most common diagnoses were cellulitis, erysipelas and herpes zoster. The presented data suggest that the burden of diseases presenting with skin lesions is significant in everyday infectious disease practice, but the overwhelming number of undiagnosed patients implies the need for further education in this area.

Nontuberculous mycobacterial skin and soft tissue infection in Hawai'i

Background

Hawaiʻi has the highest nontuberculous mycobacterial (NTM) lung infection prevalence in the United States. Limited data regarding skin and soft tissue infections (SSTI) due to NTM in Hawaiʻi exists. This study describes patient demographics, clinical courses of infection, treatment patterns, and clinical outcomes of NTM SSTIs in Hawaiʻi.

Methods

A retrospective chart review (n = 50) of patients diagnosed and treated at Hawaiʻi Pacific Health facilities for NTM SSTIs between January 2010 and July 2021 was conducted. Patient demographics, clinical course, and treatment data were collected from electronic medical records.

Results

Half of the patient population consisted of females, and the average age of patients during infection was 49 years (SD = 25.6). The majority of cases (80%) were caused by rapidly growing mycobacteria (RGM), most commonly Mycobacterium abscessus. NTM SSTI by race were Asian (48%), White (28%), and Native Hawaiian and Other Pacific Islanders (16%). Almost all Asian patients with NTM SSTI were Filipino or Japanese. Diagnosis was frequently delayed. The average time to diagnosis was 116 days. Most patients achieved complete resolution (72%) following a prolonged course of antimicrobial treatment (mean = 196 days) with surgical debridement.

Conclusion

Increased awareness among physicians and the community of non-mycobacterial skin infections is essential in Hawaiʻi due to the high prevalence of NTM and the high percentage of predisposed populations. Increased awareness of NTM could reduce delayed diagnosis and improve patient care. Further studies are required to inform optimal treatment and diagnostic strategies, improve patient outcomes, and aid public health surveillance efforts.

WSES/GAIS/WSIS/SIS-E/AAST global clinical pathways for patients with skin and soft tissue infections

Skin and soft-tissue infections (SSTIs) encompass a variety of pathological conditions that involve the skin and underlying subcutaneous tissue, fascia, or muscle, ranging from simple superficial infections to severe necrotizing infections.

Together, the World Society of Emergency Surgery, the Global Alliance for Infections in Surgery, the Surgical Infection Society-Europe, The World Surgical Infection Society, and the American Association for the Surgery of Trauma have jointly completed an international multi-society document to promote global standards of care in SSTIs guiding clinicians by describing reasonable approaches to the management of SSTIs.

An extensive non-systematic review was conducted using the PubMed and MEDLINE databases, limited to the English language. The resulting evidence was shared by an international task force with different clinical backgrounds.

Lipid Nanoparticulate Drug Delivery Systems: Recent Advances in the Treatment of Skin Disorders

The multifunctional role of the human skin is well known. It acts as a sensory and immune organ that protects the human body from harmful environmental impacts such as chemical, mechanical, and physical threats, reduces UV radiation effects, prevents moisture loss, and helps thermoregulation. In this regard, skin disorders related to skin integrity require adequate treatment. Lipid nanoparticles (LN) are recognized as promising drug delivery systems (DDS) in treating skin disorders. Solid lipid nanoparticles (SLN) together with nanostructured lipid carriers (NLC) exhibit excellent tolerability as these are produced from physiological and biodegradable lipids. Moreover, LN applied to the skin can improve stability, drug targeting, occlusion, penetration enhancement, and increased skin hydration compared with other drug nanocarriers. Furthermore, the features of LN can be enhanced by inclusion in suitable bases such as creams, ointments, gels (i.e., hydrogel, emulgel, bigel), lotions, etc. This review focuses on recent developments in lipid nanoparticle systems and their application to treating skin diseases. We point out and consider the reasons for their creation, pay attention to their advantages and disadvantages, list the main production techniques for obtaining them, and examine the place assigned to them in solving the problems caused by skin disorders.