Topical antibacterial agents

Strong Antimicrobial and Healing Effects of Beta-Acids from Hops in Methicillin-Resistant Staphylococcus aureus-Infected External Wounds In Vivo

Staphylococcus (S.) aureus is an important causative agent of wound infections with increasing incidence in the past decades. Specifically, the emergence of methicillin-resistant S. aureus (MRSA) causes serious problems, especially in nosocomial infections. Therefore, there is an urgent need to develop of alternative or supportive antimicrobial therapeutic modalities to meet these challenges. Purified compounds from hops have previously shown promising antimicrobial effects against MRSA isolates in vitro. In this study, purified beta-acids from hops were tested for their potential antimicrobial and healing properties using a porcine model of wounds infected by MRSA. The results show highly significant antimicrobial effects of the active substance in both the powder and Ambiderman-based application forms compared to both no-treatment control and treatment with Framycoin. Moreover, the macroscopic evaluation of the wounds during the treatment using the standardized Wound Healing Continuum indicated positive effects of the beta-acids on the overall wound healing. This is further supported by the microscopic data, which showed a clear improvement of the inflammatory parameters in the wounds treated by beta-acids. Thus, using the porcine model, we demonstrate significant therapeutic effects of hops compounds in the management of wounds infected by MRSA. Beta-acids from hops, therefore, represent a suitable candidate for the treatment of non-responsive nosocomial tissue infections by MRSA.

Composite P(3HB-3HV)-CS Spheres for Enhanced Antibiotic Efficiency

Natural-derived biopolymers are suitable candidates for developing specific and selective performance-enhanced antimicrobial formulations. Composite polymeric particles based on poly(3-hydroxybutyrate-co-3-hydroxyvalerate) and chitosan, P(3HB-3HV)-CS, are herein proposed as biocompatible and biodegradable delivery systems for bioproduced antibiotics: bacitracin (Bac), neomycin (Neo) and kanamycin (Kan). The stimuli-responsive spheres proved efficient platforms for boosting the antibiotic efficiency and antibacterial susceptibility, as evidenced against Gram-positive and Gram-negative strains. Absent or reduced proinflammatory effects were evidenced on macrophages in the case of Bac-/Neo- and Kan-loaded spheres, respectively. Moreover, these systems showed superior ability to sustain and promote the proliferation of dermal fibroblasts, as well as to preserve their ultrastructure (membrane and cytoskeleton integrity) and to exhibit anti-oxidant activity. The antibiotic-loaded P(3HB-3HV)-CS spheres proved efficient alternatives for antibacterial strategies.

Polyvinyl Alcohol/Chitosan/Polyhexamethylene Biguanide Phase Separation System: A Potential Topical Antibacterial Formulation with Enhanced Antimicrobial Effect

An aqueous polyvinyl alcohol (PVA)/chitosan (CHT)/polyhexamethylene biguanide (PHMB) blends (PVA/CHT/PHMB blends) has been developed as a potential low dose topical antibacterial formulation with enhanced antimicrobial effect. The preparation of PVA/CHT/PHMB blends was quite facilely, with just dissolved PVA, CHT, PHMB in water in order. There was the aggregates with 100 nm size around induced by phase separation in the blends and an aqueous two-phase system (ATPS) formed, as non-ionic polymer PVA formed a continuous phase and cationic polymer CHT and PHMB formed dispersed phases. The minimum inhibitory concentration (MIC) of PHMB in the PVA/CHT/PHMB blends was 0.5μg/mL, which was four times lower than the MIC of PHMB individually. A phase separation increased zeta potential mechanism was proposed to explain the enhanced antibacterial activities. In addition, the blends could easily form film on the skin surface with good water vapor permeability and be used as a liquid bandage to accelerate the scratch wound healing process of nude mouse. These findings provide experimental evidence that the PHMB-functionalized blends could be further explored as low-dose topical antibacterial formulations, and the nano-sized phase separation strategy could be used to design novel low-dose topical antibacterial formulations with an enhanced antimicrobial effect.

Cutibacterium acnes persists despite topical clindamycin and benzoyl peroxide

BACKGROUND

Cutibacterium (formerly Propionibacterium) acnes persists in the dermis despite standard skin antiseptic agents, prompting some surgeons to use topical antimicrobials such as benzoyl peroxide and clindamycin prior to shoulder arthroplasty surgery. However, the efficacy of these topical agents has not been established.

METHODS

The upper backs of 12 volunteers were randomized into 4 treatment quadrants: topical benzoyl peroxide, topical clindamycin, combination topical benzoyl peroxide and clindamycin, and a negative control. The corresponding topical agents were applied to each site twice daily for 3 days. A 3-mm dermal punch biopsy specimen was obtained from each site and cultured for 14 days to assess for C acnes growth. Positive cultures were assessed for the hemolytic phenotype. The McNemar test was used to compare the proportion of positive cultures in each group.

RESULTS

C acnes grew in 4 of 12 control sites (33.3%), 1 of 12 benzoyl peroxide sites (8.3%), 2 of 12 clindamycin sites (16.7%), and 2 of 12 combination benzoyl peroxide-clindamycin sites (16.7%). The C acnes hemolytic phenotype was present in 2 of 12 control specimens (16.7%) compared with 0 (0.0%) in the benzoyl peroxide group, 2 of 12 (16.7%) in the clindamycin group, and 2 of 12 (16.7%) in the combination benzoyl peroxide-clindamycin group. There were no statistically significant differences between treatment arms.

CONCLUSION

The topical application of benzoyl peroxide and clindamycin did not eradicate C acnes in all subjects. The clinical implications of these findings are yet to be determined.

In Vitro Antimicrobial Activity of Diacerein on 76 Isolates of Gram-Positive Cocci from Bacterial Keratitis Patients and In Vivo Study of Diacerein Eye Drops on Staphylococcus aureus Keratitis in Mice

Bacterial keratitis is an aggressive infectious corneal disease. With the continuing rise in antibiotic resistance and a decline in the discovery of new antibiotics, new antimicrobial drugs are now required. In the present study, we determined the antibacterial activity of diacerein, an anti-inflammatory drug, against 76 Gram-positive cocci isolated from bacterial keratitis patients in vitro and anti-Staphylococcus aureus activity in a mouse bacterial keratitis model in vivo The MICs of diacerein were tested using the broth microdilution method in vitro A BALB/c Staphylococcus aureus keratitis animal model was selected and the corneal clinical observation, viable bacteria, and hematoxylin-eosin and Gram staining of infected corneas were measured to evaluate the antibacterial efficacy of diacerein eye drops in vivo An in vivo eye irritation study was carried out by a modified Draize test in rabbits. Our in vitro results showed that diacerein possesses satisfactory antibacterial activity against the majority of Gram-positive cocci (60/76), including all 57 tested Staphylococcus spp. and 3 Enterococcus spp. The in vivo experiment showed that diacerein eye drops reduced bacterial load and improved ocular clinical scores after topical administration of diacerein drops on infected corneas. The ocular irritation test revealed that diacerein eye drop had excellent ocular tolerance. These results indicated that diacerein possesses in vivo anti-Staphylococcus aureus activity. We suggest that diacerein is a possible topically administered drug for Staphylococcus aureus-infected patients, especially those with ocular surface inflammatory disorders.

Current and Emerging Topical Antibacterials and Antiseptics: Agents, Action, and Resistance Patterns

Bacterial skin infections represent some of the most common infectious diseases globally. Prevention and treatment of skin infections can involve application of a topical antimicrobial, which may be an antibiotic (such as mupirocin or fusidic acid) or an antiseptic (such as chlorhexidine or alcohol). However, there is limited evidence to support the widespread prophylactic or therapeutic use of topical agents. Challenges involved in the use of topical antimicrobials include increasing rates of bacterial resistance, local hypersensitivity reactions (particularly to older agents, such as bacitracin), and concerns about the indiscriminate use of antiseptics potentially coselecting for antibiotic resistance. We review the evidence for the major clinical uses of topical antibiotics and antiseptics. In addition, we review the mechanisms of action of common topical agents and define the clinical and molecular epidemiology of antimicrobial resistance in these agents. Moreover, we review the potential use of newer and emerging agents, such as retapamulin and ebselen, and discuss the role of antiseptic agents in preventing bacterial skin infections. A comprehensive understanding of the clinical efficacy and drivers of resistance to topical agents will inform the optimal use of these agents to preserve their activity in the future.

The Neurostimulation Appropriateness Consensus Committee (NACC) Recommendations for Infection Prevention and Management

INTRODUCTION

The use of neurostimulation for pain has been an established therapy for many decades and is a major tool in the arsenal to treat neuropathic pain syndromes. Level I evidence has recently been presented to substantiate the therapy, but this is balanced against the risk of complications of an interventional technique.

METHODS

The Neurostimulation Appropriateness Consensus Committee (NACC) of the International Neuromodulation Society convened an international panel of well published and diverse physicians to examine the best practices for infection mitigation and management in patients undergoing neurostimulation. The NACC recommendations are based on evidence scoring and peer-reviewed literature. Where evidence is lacking the panel added expert opinion to establish recommendations.

RESULTS

The NACC has made recommendations to improve care by reducing infection and managing this complication when it occurs. These evidence-based recommendations should be considered best practices in the clinical implantation of neurostimulation devices.

CONCLUSION

Adhering to established standards can improve patient care and reduce the morbidity and mortality of infectious complications in patients receiving neurostimulation.

Diabetic Foot Infections: an Update in Diagnosis and Management

Foot infections are a common problem in patients with diabetes and a risk factor for limb amputation. They occur as a result of skin ulceration, which facilitates penetration of pathogens to deeper tissues. The diagnosis of infection is clinical. Aerobic gram-positive cocci are the most common pathogens. Ulcers which are chronic, preceded by administration of antibiotics and hospitalization or complicated by severe infection are polymicrobial. Antibiotic therapy is initially empiric based on the severity of the infection. Definitive therapy is modified according to the results of the microbiological culture and the response to empiric treatment. The optimal duration of antibiotic therapy ranges from 1-2 weeks for mild infections to 2-4 weeks and even longer for severe infections and osteomyelitis. Surgical consultation should be sought for infections complicated with abscesses, necrotizing fasciitis or osteomyelitis. With appropriate care, infection resolves in about 80-90% of non-limb threatening and in about 60% of severe infections.

Frequent isolation of Propionibacterium acnes from the shoulder dermis despite skin preparation and prophylactic antibiotics

BACKGROUND

In vitro, Propionibacterium acnes (P acnes) is highly susceptible to commonly used antibiotics and antiseptics, yet in vivo, it still causes postsurgical infections of the shoulder. We hypothesized that the local environment within the pilosebaceous glands protects P acnes and that incision of the skin transects these glands, exposing viable P acnes to the wound.

METHODS

Fifty consecutive patients undergoing open shoulder surgery were prospectively studied. Prophylactic antibiotics were administered to all patients. Microbiologic swabs of the skin surface were taken before and after skin preparation with 70% alcoholic chlorhexidine. The skin was incised, and a further swab and dermal biopsy specimen were taken.

RESULTS

P acnes was cultured in 21 of 50 prepreparation skin surface swabs (42%), 7 of 50 postpreparation skin surface swabs (14%), 26 of 50 dermal swabs (52%), and 20 of 50 dermal biopsy specimens (40%). There was a significantly higher incidence of P acnes growth from the skin surface (P = .009) and dermis (P = .01) of patients aged ≤50 years old and in the dermal biopsy specimens of patients undergoing revision surgery (P = .01) and a trend toward increased incidence of P acnes in men. P acnes growth from a prepreparation skin surface swab had a sensitivity of 69%, specificity of 88%, positive predictive value of 86%, and negative predictive value of 72% at predicting subsequent P acnes growth from the dermal swab or biopsy specimen.

CONCLUSIONS

Viable P acnes persists within the skin dermis, despite standard antimicrobial precautions. These findings suggest that incising the skin is likely to lead to deep seeding of the surgical wound, which has implications for the pathogenesis and prevention of postsurgical shoulder infections.

Surgical hand antisepsis to reduce surgical site infection

BACKGROUND

Medical professionals routinely carry out surgical hand antisepsis before undertaking invasive procedures to destroy transient micro-organisms and inhibit the growth of resident micro-organisms. Antisepsis may reduce the risk of surgical site infections (SSIs) in patients.

OBJECTIVES

To assess the effects of surgical hand antisepsis on preventing surgical site infections (SSIs) in patients treated in any setting. The secondary objective is to determine the effects of surgical hand antisepsis on the numbers of colony-forming units (CFUs) of bacteria on the hands of the surgical team.

SEARCH METHODS

In June 2015 for this update, we searched: The Cochrane Wounds Group Specialized Register; The Cochrane Central Register of Controlled Trials (CENTRAL) (The Cochrane Library); Ovid MEDLINE; Ovid MEDLINE (In-Process & Other Non-Indexed Citations) and EBSCO CINAHL. There were no restrictions with respect to language, date of publication or study setting.

SELECTION CRITERIA

Randomised controlled trials comparing surgical hand antisepsis of varying duration, methods and antiseptic solutions.

DATA COLLECTION AND ANALYSIS

Three authors independently assessed studies for inclusion and trial quality and extracted data.

MAIN RESULTS

Fourteen trials were included in the updated review. Four trials reported the primary outcome, rates of SSIs, while 10 trials reported number of CFUs but not SSI rates. In general studies were small, and some did not present data or analyses that could be easily interpreted or related to clinical outcomes. These factors reduced the quality of the evidence. SSIsOne study randomised 3317 participants to basic hand hygiene (soap and water) versus an alcohol rub plus additional hydrogen peroxide. There was no clear evidence of a difference in the risk of SSI (risk ratio (RR) 0.97, 95% CI 0.77 to 1.23, moderate quality evidence downgraded for imprecision).One study (500 participants) compared alcohol-only rub versus an aqueous scrub and found no clear evidence of a difference in the risk of SSI (RR 0.56, 95% CI 0.23 to 1.34, very low quality evidence downgraded for imprecision and risk of bias).One study (4387 participants) compared alcohol rubs with additional active ingredients versus aqueous scrubs and found no clear evidence of a difference in SSI (RR 1.02, 95% CI 0.70 to 1.48, low quality evidence downgraded for imprecision and risk of bias).One study (100 participants) compared an alcohol rub with an additional ingredient versus an aqueous scrub with a brush and found no evidence of a difference in SSI (RR 0.50, 95% CI 0.05 to 5.34, low quality evidence downgraded for imprecision). CFUsThe review presents results for a number of comparisons; key findings include the following.Four studies compared different aqueous scrubs in reducing CFUs on hands.Three studies found chlorhexidine gluconate scrubs resulted in fewer CFUs than povidone iodine scrubs immediately after scrubbing, 2 hours after the initial scrub and 2 hours after subsequent scrubbing. All evidence was low or very low quality, with downgrading typically for imprecision and indirectness of outcome. One trial comparing a chlorhexidine gluconate scrub versus a povidone iodine plus triclosan scrub found no clear evidence of a difference-this was very low quality evidence (downgraded for risk of bias, imprecision and indirectness of outcome).Four studies compared aqueous scrubs versus alcohol rubs containing additional active ingredients and reported CFUs. In three comparisons there was evidence of fewer CFUs after using alcohol rubs with additional active ingredients (moderate or very low quality evidence downgraded for imprecision and indirectness of outcome). Evidence from one study suggested that an aqueous scrub was more effective in reducing CFUs than an alcohol rub containing additional ingredients, but this was very low quality evidence downgraded for imprecision and indirectness of outcome.Evidence for the effectiveness of different scrub durations varied. Four studies compared the effect of different durations of scrubs and rubs on the number of CFUs on hands. There was evidence that a 3 minute scrub reduced the number of CFUs compared with a 2 minute scrub (very low quality evidence downgraded for imprecision and indirectness of outcome). Data on other comparisons were not consistent, and interpretation was difficult. All further evidence was low or very low quality (typically downgraded for imprecision and indirectness).One study compared the effectiveness of using nail brushes and nail picks under running water prior to a chlorhexidine scrub on the number of CFUs on hands. It was unclear whether there was a difference in the effectiveness of these different techniques in terms of the number of CFUs remaining on hands (very low quality evidence downgraded due to imprecision and indirectness).

AUTHORS' CONCLUSIONS

There is no firm evidence that one type of hand antisepsis is better than another in reducing SSIs. Chlorhexidine gluconate scrubs may reduce the number of CFUs on hands compared with povidone iodine scrubs; however, the clinical relevance of this surrogate outcome is unclear. Alcohol rubs with additional antiseptic ingredients may reduce CFUs compared with aqueous scrubs. With regard to duration of hand antisepsis, a 3 minute initial scrub reduced CFUs on the hand compared with a 2 minute scrub, but this was very low quality evidence, and findings about a longer initial scrub and subsequent scrub durations are not consistent. It is unclear whether nail picks and brushes have a differential impact on the number of CFUs remaining on the hand. Generally, almost all evidence available to inform decisions about hand antisepsis approaches that were explored here were informed by low or very low quality evidence.

Antagonistic interactions of "Ya-Sa-Marn-Phlae" ethanol extract in combination with topical antiseptics against clinical isolates of Staphylococcus aureus

This investigation was aimed at assessing a possible interaction of a traditional Thai herbal recipe, "Ya-Sa-Marn-Phlae (YSMP)," used for wound treatments with topical antiseptics, povidone-iodine (PI) solution and hydrogen peroxide (H2O2), and effects of THR-SK010 alone and the combinations on Staphylococcus aureus. Antibacterial activities of ethanol extracts from the herbal recipe were determined against both methicillin resistant Staphylococcus aureus (MRSA) and methicillin-susceptible S. aureus (MSSA). YSMP exhibited remarkable antistaphylococcal activity with MIC values of 3.9-7.8 μg/mL. This recipe possessed bacteriostatic activity and did not reduce the tolerance of both MRSA and MSSA isolates to the high ionic strength. Interaction between THR-SK010 and the antiseptics was carried out by checkerboard testing and time-kill assay. Both indifferent and slightly antagonistic effects were observed with THR-SK010/PI and THR-SK010/H2O2 combinations against the tested isolates. In addition to commercially available antiseptics, THR-SK010 offered additional therapeutic options for the decolonization of MRSA and MSSA. Topical application of plant extracts with antioxidant activity, such as THR-SK010, should not be used immediately with PI or H2O2 and further investigation on this interaction is needed.

The economics of hemodialysis catheter-related infection prophylaxis

Hemodialysis central venous catheter (CVC) use is associated with the highest morbidity, mortality, and cost of all types of hemodialysis vascular access. CVC-related infection drives much of the cost associated with CVC use. The magnitude of the cost associated with CVC-related infection varies depending on the type and severity of that infection; however, estimates of the total direct and indirect costs associated with hospitalizations due to hemodialysis CVC-related infections range from 17,000 USD to 32,000 USD per episode. Thus, it is critically important, to not only have effective strategies to limit CVC-related infection but also evaluate whether these strategies are an efficient use of resources. Prophylactic strategies can be considered economically efficient only if the value of its implementation and the corresponding drop in infection rate offer greater value than standard care. The optimal CVC-related infection prophylaxis strategy should work to limit infection risk with minimal risk, inconvenience, and discomfort to the patient, and at minimal cost. The aim of this review was to examine the clinical and economic impact of some commonly described interventions used for CVC infection prophylaxis.

Recent advances in topical wound care

There are a wide variety of dressing techniques and materials available for management of both acute wounds and chronic non-healing wounds. The primary objective in both the cases is to achieve a healed closed wound. However, in a chronic wound the dressing may be required for preparing the wound bed for further operative procedures such as skin grafting. An ideal dressing material should not only accelerate wound healing but also reduce loss of protein, electrolytes and fluid from the wound, and help to minimize pain and infection. The present dictum is to promote the concept of moist wound healing. This is in sharp contrast to the earlier practice of exposure method of wound management wherein the wound was allowed to dry. It can be quite a challenge for any physician to choose an appropriate dressing material when faced with a wound. Since wound care is undergoing a constant change and new products are being introduced into the market frequently, one needs to keep abreast of their effect on wound healing. This article emphasizes on the importance of assessment of the wound bed, the amount of drainage, depth of damage, presence of infection and location of wound. These characteristics will help any clinician decide on which product to use and where,in order to get optimal wound healing. However, there are no ‘magical dressings’. Dressings are one important aspect that promotes wound healing apart from treating the underlying cause and other supportive measures like nutrition and systemic antibiotics need to be given equal attention.

Bacterial skin colonization and infections in patients with atopic dermatitis

Atopic Dermatitis is a chronic inflammatory skin disease that affects a large number of children and adults. The disease results from an interaction between genetic predisposition, host environment, skin barrier defects, and immunological factors. A major aggravating factor associated with Atopic Dermatitis is the presence of microorganisms on the patient's skin surface. Staphylococcus aureus and Streptococcus pyogenes, for instance, can exacerbate chronic skin inflammation. As a result, antimicrobials have often been prescribed to control the acute phase of the disease. However, increased bacterial resistance to antimicrobial agents has made it difficult for dermatologists to prescribe appropriate medication. In the presence of disseminated dermatitis with secondary infection, systemic antibiotics need to be prescribed; however, treatment should be individualized, in an attempt to find the most effective antibiotic with fewer side effects. Also, the medication should be used for as short as possible in order to minimize bacterial resistance.

An update on pharmacological interventions for diabetic foot ulcers

Diabetic foot ulcers are the most common lower extremity complications of diabetes. Peripheral neuropathy and peripheral vascular disease are the underlying risk factors for diabetic foot ulcers, subsequently leading to infections and requiring antimicrobial therapy for the management of the disease. Each risk factor is a target for clinical intervention, with the intent to delay or prevent disease progression to amputation. The effective therapy includes interdisciplinary care, which involves optimized pharmacological interventions in concert with other treatments such as debridement strategies and specialized wound dressings. The pharmacological therapy alone cannot lead to successful therapy, and therefore, these supplementary techniques/modalities should not be overlooked. It is therefore the aim of this report to review various pharmacological interventions, specific to the diabetic foot and wound healing, along with incorporation of advanced therapies required to achieve a multifaceted treatment of diabetic foot ulcers and provide basis for superior drugs as well as drug delivery systems.