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Synthetic mimics of antimicrobial peptides (AMPs) is a promising class of molecules for a variety of antimicrobial applications. Several hurdles must be passed before effective systemic infection therapies with AMPs can be achieved, but the path to effective topical treatment of skin, nail, and soft tissue infections appears less challenging to navigate. Skin and soft tissue infection is closely coupled to the emergence of antibiotic resistance and represents a major burden to the healthcare system. The present study evaluates the promising synthetic cationic AMP mimic, AMC-109, for treatment of skin infections in vivo. The compound is evaluated both in impregnated cotton wound dressings and in a gel formulation against skin infections caused by Staphylococcus aureus and methicillin resistant S. aureus. Both the ability to prevent colonization and formation of an infection, as well as eradicate an ongoing infection in vivo with a high bacterial load, were evaluated. The present work demonstrates that AMC-109 displays a significantly higher antibacterial activity with up to a seven-log reduction in bacterial loads compared to current clinical standard therapy; Altargo cream (1% retapamulin) and Fucidin cream (2% fusidic acid) in the in vivo wound models. It is thus concluded that AMC-109 represents a promising entry in the development of new and effective remedies for various skin infections.

Fusidic acid, a representative member of fungal fusidane triterpenoids, has been clinically used as an antibiotic. In the present study, fusidic acid (1), and its known analogs 16-desacetylfusidic acid (2) and 3β,20-dihydroxy-protosta-16,24-dien-29-oic acid (4), together with one new derivative acremonidiol A (3), were isolated from the endophytic fungus, Acremonium pilosum F47. Their structures were determined by MS and NMR. The spectroscopic data of 2 are firstly reported here. The antibacterial efficacies of 1-4 were evaluated against four selected Gram-positive or Gram-negative bacteria. As expected, only compound 1 showed strong inhibitory effect on Gram-positive bacteria Staphylococcus aureus and Bacillus subtilis.

Impetigo, a highly contagious bacterial skin infection commonly occurring in young children, but adults may also be affected. The superficial skin infection is mainly caused by Staphylococcus aureus (S. aureus) and less frequently by Streptococcus pyogenes (S. pyogenes). Antimicrobial resistance has become a worldwide concern and needs to be addressed when selecting treatment for impetigo patients. An evidence-based impetigo treatment algorithm was developed to address the treatment of impetigo for pediatric and adult populations.An international panel of pediatric dermatologists, dermatologists, pediatricians, and pediatric infectious disease specialists employed a modified Delphi technique to develop the impetigo treatment algorithm. Treatment recommendations were evidence-based, taking into account antimicrobial stewardship and the increasing resistance to oral and topical antibiotics.The algorithm includes education and prevention of impetigo, diagnosis and classification, treatment measures, and follow-up and distinguishes between localized and widespread or epidemic outbreaks of impetigo. The panel adopted the definition of localized impetigo of fewer than ten lesions and smaller than 36 cm2 area affected in patients of two months and up with no compromised immune status. Resistance to oral and topical antibiotics prescribed for the treatment of impetigo such as mupirocin, retapamulin, fusidic acid, have been widely reported.When prescribing antibiotics, it is essential to know the local trends in antibiotic resistance. Ozenoxacin cream 1% is highly effective against S. pyogenes and S. aureus, including methycyllin-susceptible and resistant strains (MRSA), and may be a suitable option for localized impetigo.J Drugs Dermatol. 2021;20(2):134-142. doi:10.36849/JDD.5475 THIS ARTICLE HAD BEEN MADE AVAILABLE FREE OF CHARGE. PLEASE SCROLL DOWN TO ACCESS THE FULL TEXT OF THIS ARTICLE WITHOUT LOGGING IN. NO PURCHASE NECESSARY. PLEASE CONTACT THE PUBLISHER WITH ANY QUESTIONS.

Pseudomonas putida is widely recognized as a spoiler of fresh foods under cold storage, and recently associated also with infections in clinical settings. The presence of antibiotic resistance genes (ARGs) could be acquired and transmitted by horizontal genetic transfer and further increase the risk associated with its persistence in food and the need to be deeper investigated. Thus, in this work we presented a genomic and phenotypic analysis of the psychrotrophic P. putida ITEM 17297 to provide new insight into AR mechanisms by this species until now widely studied only for its spoilage traits. ITEM 17297 displayed resistance to several classes of antibiotics and it also formed huge amounts of biofilm; this latter registered increases at 15 ​°C in comparison to the optimum growth condition (30 ​°C). After ITEM 17297 biofilms exposure to antibiotic concentrations higher than 10-fold their MIC values no eradication occurred; interestingly, biomasses of biofilm cultivated at 15 ​°C increased their amount in a dose-dependent manner. Genomic analyses revealed determinants (RND-systems, ABC-transporters, and MFS-efflux pumps) for multi-drugs resistance (β-lactams, macrolides, nalidixic acid, tetracycline, fusidic acid and bacitracin) and a novel ampC allele. Biofilm and motility related pathways were depicted underlying their contribution to AR. Based on these results, underestimated psychrotrophic pseudomonas, such as the herein studied ITEM 17297 strain, might assume relevance in relation to the risk associated with the transfer of antimicrobial resistance genes to humans through cold stored contaminated foods. P. putida biofilm and AR related molecular targets herein identified will provide a basis to clarify the interaction between AR and biofilm formation and to develop novel strategies to counteract the persistence of multidrug resistant P. putida in the food chain.

Objective: The aim of this study was to investigate the genetic determinants of fusidic acid (FA) resistance in MRSA isolated from patients in Kuwait hospitals. Methods: The minimum inhibitory concentration (MIC) of FA was tested with E-test strips. Genetic determinants of FA were determined by PCR and DNA microarray. Staphylococcal protein A gene (spa) typing and DNA microarray analysis were used to study their genetic backgrounds. Results: The FA MIC ranged from 2 mg/L to >256 mg/L. Of the 97 isolates, 79 (81.4%) harbored fusC, 14 isolates harbored fusA mutations (fusA), and 4 isolates harbored fusB. Isolates with fusA mutations expressed high FA MIC (MIC >256 mg/L), whereas those with fusC and fusB expressed low FA MIC (MIC 2–16 mg/L). The isolates belonged to 23 spa types and 12 clonal complexes (CCs). The major spa types were t688 (n = 25), t311 (n = 14), t860 (n = 8), and t127 (n = 6) which constituted 54.6% of the isolates. The 12 CCs were CC1, CC5, CC8, CC15, CC22, CC80, CC88, and CC97 with CC5 (45.6%) and CC97 (13.2%) as the dominant CCs. Conclusions: The MRSA isolates belonged to diverse genetic backgrounds with the majority carrying the fusC resistance determinants. The high prevalence of FA resistance belonging to diverse genetic backgrounds warrants a review of FA usage in the country to preserve its therapeutic benefits.

Background: Pyogenic liver abscess (PLA) is a rare but life-threatening disease, with a frequency ranging from 10.83 to 17.45 per 100,000 persons. The major cause of PLA is bacterial infection of liver parenchyma. The present research study was designed to investigate the common microbes causing PLA in Peshawar (Pakistan) and to evaluate a variety of the most capable and efficient antibiotics for treatment of PLA. Methods: A 7-year (2012 - 2018) retrospective demographic study of medical records of all PLA patients (n = 379) admitted to the Hayatabad Medical Complex (HMC) and Khyber Teaching Hospital (KTH) was initially performed. The demographic study was followed by biochemical tests and antibiotic resistivity tests of microorganisms, isolated from available samples and selected from literature using web services. Results & Conclusion: The demographic data revealed that 70% of the PLA patients were under the age of 50, with male predominance (male to female ratio of 3:1). It was concluded that K. pneumonia, poly-microbes (K. pneumonia and Citrobacter), and E. coli are the most common microbes involved in causing PLA in the population of Peshawar. E.coli, Citrobacter and K. pneumonia were sensitive to Cefixime and Ciprofloxacin (100% sensitivity rate), but showed significant resistance against Amoxycillin, Oxacillin and Fusidic Acid. It is, therefore, prudent to practice susceptibility-directed antibiotic therapy.

Introduction. Dermatologic adverse events (DAEs) occur in 50-90% of cases during anti-EGFR monoclonal antibody treatment. Positive correlation between the severity of acneiform rash (AR) and the effectiveness of anti-EGFR management is established. Low effectiveness of traditional treatment for AR impairs patients’ compliance, leads to dose reduction or drug discontinuation, affecting treatment results.Objective. To assess the effectiveness of traditional and proposed combined treatment for AR associated with anti-EGFR monoclonal antibody therapy.Materials and methods. 44 patients with grade I-II acneiform rash were included in a 12-week study. Patients were divided into 3 equal groups and received different treatment: group 1a – traditional therapy, group 1b – combined continuous therapy, and group 1c – combined intermittent therapy. Assessment of clinical outcomes was performed with DLQI, IGA score, and the NCI CTCAE v. 4.03.Results. The severity of AR in groups 1b and 1c improved by the end of week 1, and this trend was kept until the end of the study. The improvement was more prominent in group 1c comparing to group 1b. The severity of AR in group 1a improved by the end of week 1. During weeks 2 and 3 there was no significant change. At week 4 a deterioration of the evaluated parameters was registered, and the treatment regimen in group 1a was changed according to the treatment protocols of group 1c with rapid improvement of AR.Conclusion. Combined intermittent therapy with systemic doxycycline and topical therapy with metronidazole 1% gel and cream with hydrocortisone acetate 1% and fusidic acid 2% showed the best effectiveness and tolerability in patients with anti-EGFR monoclonal antibody-related AR.

The goal of this study was to identify antibiotics with potential risk in river water of the megacity Beijing, China. This was accomplished by using a tiered approach that combined hazard (phase I) and monitoring-based risk (phase II) assessment. Ninety-five candidate antibiotics were screened and 31 was identified as hazardous during phase I assessment. Of these hazardous antibiotics, 29 were identified as persistent and 7 were identified as bioaccumulative antibiotics. Fluoroquinolones, macrolides, sulfonamides, and aminoglycosides account for over 80% of these hazardous antibiotics. During phase II, four antibiotics (erythromycylamine, cefotaxime, ampicillin, and fusidic acid) that were not previously reported were detected in the surface water sampled from four major rivers in Beijing, with concentrations ranging from not detected to approximately 300 ng/L. The ecological risk assessment showed that erythromycylamine, cefotaxime, and ampicillin posed low to high levels of risk to the aquatic organisms. To summarize, erythromycylamine, cefotaxime, and ampicillin were identified as priority antibiotics in rivers in Beijing, China. Our results demonstrated the necessity of conducting monitoring-based verification process in identification of priority antibiotics in a specific region.

Fusidic acid (FA) is renowned as an effective bacteriostatic agent obtained from the fungus Fusidium coccineum, used for treating various eye and skin disorders. The objective of the present study was to develop, characterize, and evaluate the antibacterial activity of a novel FA nanoemulgel for topical skin application. Primarily, various fusidic acid nanoemulsion formulations were fabricated using different concentrations of myrrh essential oil, Tween 80 as a surfactant, and Transcutol® P as a co-surfactant. A Box–Behnken design was employed to select the optimized FA nanoemulsion formulation, based on the evaluated particle size and % of in vitro release as dependent variables. The optimized formula was incorporated within a hydrogel to obtain an FA nanoemulgel (FA-NEG) preparation. The formulated FA-NEG was evaluated for its visual appearance, pH, viscosity, and spreadability, compared to its corresponding prepared fusidic acid gel. In vitro release, kinetic study, and ex vivo drug permeation were implemented, followed by formulation stability testing. The FA-NEG exhibited a smooth and homogeneous appearance, pH value (6.61), viscosity (25,265 cP), and spreadability (33.6 mm), which were all good characteristics for appropriate topical application. A total of 59.3% of FA was released from the FA-NEG after 3 h. The ex vivo skin permeability of the FA-NEG was significantly enhanced by 3.10 ± 0.13-fold, showing SSTF of 111.2 ± 4.5 µg/cm2·h when compared to other formulations under investigation (p < 0.05). No irritation was observed upon applying the FA-NEG to animal skin. Eventually, it was revealed that the FA-NEG displayed improved antibacterial activity against a wide variety of bacteria when compared to its corresponding FA gel and marketed cream, indicating the prospective antibacterial effect of myrrh essential oil. In conclusion, the recommended formulation offers a promising antibacterial approach for skin infections.

Bifidobacteria are typical commensals inhabiting the human intestine and are beneficial to the host because of their probiotic properties. One of the risks concerning probiotics is the potential of introducing antibiotic resistance genes (ARGs) to the host gut pathogens. This study was aimed to depict the general antibiotic resistance characteristics of the genus Bifidobacterium by combining the reported phenotype dataset and in silico genotype prediction. Bifidobacteria were mostly reported to be sensitive to beta-lactams, glycopeptides, chloramphenicol, and rifampicin, but resistant to aminoglycosides, polypeptides, quinolones, and mupirocin. Generally, the resistance phenotypes to erythromycin, tetracycline, fusidic acid, metronidazole, clindamycin, and trimethoprim were variable. Besides cmX and tetQ, characterized in bifidobacterial resident plasmids, 3520 putative ARGs were identified from 831 bifidobacterial genomes through BLASTP search. The identified ARGs matched thirty-eight reference ARGs, four of which seemed to be mutant housekeeping genes. The two high-abundant ARGs, tetW and ermX, were found to have different distribution traits. The predicted ARGs reasonably explained most of the corresponding resistant phenotypes in the published literature.

BACKGROUND Inflammation and postinflammatory hyperpigmentation (PIH) are two adverse side effects of ablative fractional CO2 laser (ablative Fr CO2 ) treatment for both rejuvenation and acne scars. AIMS To evaluate the efficacy of fusidic acid cream versus erythromycin ointment as postoperative therapy in patients who underwent ablative Fr CO2 treatment for atrophic acne scars. METHODS Sixty Chinese patients who fulfilled the study criteria were recruited and randomly assigned to an experimental group treated with fusidic acid cream or a control group treated with erythromycin ointment. Postoperative treatment lasted for 7 days in each group. Each patient had two follow-up visits at 8 and 12 weeks. In total, three patients dropped out of the study, one in the experimental group at week 8 and two in the control group at weeks 8 and 12. Baseline and postoperative inflammation and PIH were assessed by facial examination, photographs, and questionnaires. Besides, PIH was evaluated by the Hyperpigmentation Activity and Severity Index (HASI) and a five-point grading system. RESULTS Moderate-to-severe PIH was observed in both groups. However, the mean HASI score and severity of PIH in the experimental group were lower than those of the control group at weeks 8 and 12 (P

Burn is the immense public health issue globally. Low and middle income countries face extensive deaths owing to burn injuries. Availability of conventional therapies for burns has always been painful for patients as well as expensive for our health system. Pharmaceutical experts are still searching reliable, cheap, safe and effective treatment options for burn injuries. Fusidic acid is an antibiotic of choice for the management of burns. However, fusidic acid is encountering several pharmaceutical and clinical challenges like poor skin permeability and growing drug resistance against burn wound microbes like Methicillin resistant Staphylococcus aureus (MRSA). Therefore, an effort has been made to present a concise review about molecular pathway followed by fusidic acid in the treatment of burn wound infection in addition to associated pros and cons. Furthermore, we have also summarized chitosan and phospholipid based topical dermal delivery systems customized by our team for the delivery of fusidic acid in burn wound infections on case-to-case basis. However, every coin has two sides. We recommend the integration of in-silico docking techniques with natural biomacromolecules while designing stable, patient friendly and cost effective topical drug delivery systems of fusidic acid for the management of burn wound infection as future opportunities.

Significance The World Health Organization has declared antimicrobial resistance one of the greatest threats to human health. Understanding the molecular mechanisms by which bacteria resist the effects of antibiotic therapies is central to understanding antimicrobial resistance and to informing the development of new treatments that can circumvent these resistance mechanisms. This study reveals the molecular details of the mechanism of FusB-mediated resistance to fusidic acid, an important clinical treatment for Staphylococcus aureus infections, including methicillin-resistant Staphylococcus aureus. Here we elucidate an antibiotic resistance mechanism driven by an allosteric effect on the conformational flexibility of the drug target., Antibiotic resistance in clinically important bacteria can be mediated by target protection mechanisms, whereby a protein binds to the drug target and protects it from the inhibitory effects of the antibiotic. The most prevalent source of clinical resistance to the antibiotic fusidic acid (FA) is expression of the FusB family of proteins that bind to the drug target (Elongation factor G [EF-G]) and promote dissociation of EF-G from FA-stalled ribosome complexes. FusB binding causes changes in both the structure and conformational flexibility of EF-G, but which of these changes drives FA resistance was not understood. We present here detailed characterization of changes in the conformational flexibility of EF-G in response to FusB binding and show that these changes are responsible for conferring FA resistance. Binding of FusB to EF-G causes a significant change in the dynamics of domain III of EF-GC3 that leads to an increase in a minor, more disordered state of EF-G domain III. This is sufficient to overcome the steric block of transmission of conformational changes within EF-G by which FA prevents release of EF-G from the ribosome. This study has identified an antibiotic resistance mechanism mediated by allosteric effects on the dynamics of the drug target.

Fusidane-type antibiotics represented by fusidic acid, helvolic acid, and cephalosporin P1 have very similar core structures, but they are produced by fungi belonging to different taxonomic groups. The origin and evolution of fusidane-type antibiotics biosynthetic gene clusters (BGCs) in different antibiotics producing strains remained an enigma. In this study, we investigated the distribution and evolution of the fusidane BGCs in 1,284 fungal genomes. We identified 12 helvolic acid BGCs, 4 fusidic acid BGCs, and 1 cephalosporin P1 BGC in Pezizomycotina fungi. Phylogenetic analyses indicated six horizontal gene transfer (HGT) events in the evolutionary trajectory of the BGCs, including 1) three transfers across Eurotiomycetes and Sordariomycetes classes; 2) one transfer between genera under Sordariomycetes class; and 3) two transfers within Aspergillus genus under Eurotiomycetes classes. Finally, we proposed that the ancestor of fusidane BGCs would be originated from the Zoopagomycota by ancient HGT events according to the phylogenetic trees of key enzymes in fusidane BGCs (OSC and P450 genes). Our results extensively clarify the evolutionary trajectory of fusidane BGCs by HGT among distantly related fungi and provide new insights into the evolutionary mechanisms of metabolic pathways in fungi.

Introduction: Staphylococcus aureus harboring Panton Valentine Leucocidin gene are emerging and spreading worldwide. PVL gene was first identified by Noel Panton and Francis Valentine in 1932 who IC Pakistan only limited data is available regarding the effect of PVL gene on sensitivity pattern of Staphylococcus aureus. Therefore, this study was conducted to understand the antimicrobial sensitivity pattern of both PVL positive and negative Staphylococcus aureus isolates. Aims & Objectives: This study was conducted to understand the antimicrobial sensitivity pattern of both PVL positive and PVL negative Staphylococcus aureus isolated from pus samples received from various indoor and outdoor departments of a tertiary care hospital of Lahore. Place and duration of study: Microbiology and Molecular Biology Laboratory Shaikh Zayed Hospital Lahore. Duration of study is one year after the approval of research topic. Material & Methods: A total of 384 Staphylococcus aureus isolates from skin and soft tissue infections were identified and selected. Their antimicrobial sensitivity testing was done by Kirby disc diffusion method using Muller Hinton agar. Results: Frequencies of PVL gene in MRSA and MSSA were 51% and 44% respectively. Frequency of PVL gene was also found to be high in Ciprofloxacin sensitive, Gentamicin sensitive, Erythromycin resistant and fusidic acid resistant isolates. Conclusion: Almost half of Staphylococcus aureus isolates were found PVL positive. They were mostly multidrug resistant. The PVL positive Staphylococcus aureus isolates showed high resistance against antibiotics than PVL negative isolates

The global antimicrobial resistance crisis has prompted worldwide efforts to develop new and more efficient antimicrobial compounds, as well as to develop new drug delivery strategies and targeting mechanisms. This study aimed to synthesize a novel polyethylene glycol-fusidic acid (PEG-FA) conjugate for self-assembly into nano-sized structures and explore its potential for simultaneously enhancing aqueous solubility and antibacterial activity of FA. In addition, the ability of PEG-FA to bind to HSA with lower affinity than FA is also investigated. Haemolysis and in vitro cytotoxicity studies confirmed superior biosafety of the novel PEG-FA compared to FA. The water solubility of FA after PEG conjugation was increased by 25-fold compared to the bare drug. PEG-FA nanoparticles displayed particle size, polydispersity index and zeta potential of 149.3 ± 0.21 nm, 0.267 ± 0.01 and 5.97 ± 1.03 mV, respectively. Morphology studies using high-resolution transmission electron microscope revealed a homogenous spherical shape of the PEG-FA nanoparticles. In silico studies showed that Van der Waals forces facilitated PEG-FA self-assembly. HSA binding studies showed that PEG-FA had very weak or no interaction with HSA using in silico molecular docking (-2.93 kcal/mol) and microscale thermophoresis (Kd=14999 ± 1.36 µM), which may prevent bilirubin displacement. Conjugation with PEG did not inhibit the antibacterial activity of FA but rather enhanced it by 2.5-fold against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus, compared to the bare FA. These results show that PEG-FA can simultaneously enhance solubility and antibacterial activity of FA, whilst also reducing binding of HSA to decrease its side effects. Communicated by Ramaswamy H. Sarma

The USA300 clone, which produces Panton-Valentine leukocidin (PVL), is a major pathogenic community-acquired methicillin-resistant Staphylococcus aureus (CA-MRSA) clone that causes intractable skin infections. Recently, PVL-positive CA-MRSA, including USA300 clones, have emerged in both communities and hospitals in Japan. To prevent an outbreak of PVL-positive MRSA, infected patients should be treated with effective antimicrobial agents at community clinics. Herein, we investigate molecular epidemiological characteristics of PVL-positive MRSA isolated from outpatients with skin and soft tissue infections (SSTI), which are common community-onset infectious diseases. The detection rate of MRSA was 24.9% (362 strains) out of 1455 S. aureus strains isolated between 2013 and 2017. Among the MRSA strains, 15.5% (56 strains) were PVL-positive strains and associated with deep-seated skin infections. Molecular epidemiological analyses of PVL-positive MRSA showed that USA300 was the predominant clone (53.6%, 30 strains) and was identified in Kanto (18 strains), Kagawa (nine strains), Tohoku (two strains) and Hokkaido (one strain). Notably, minocycline and fusidic acid were effective against all PVL-positive MRSA strains. Hence, our data reveals the current status of PVL-positive MRSA isolated from patients with SSTI in Japan. Continuous surveillance of CA-MRSA is necessary to monitor latest prevalence rates and identify effective antimicrobial agents for PVL-positive MRSA strains.

Impetigo is the most common bacterial skin infection in children. The disease has two forms: nonbullous and bullous, of which nonbullous is the most common (70 %). Impetigo is caused by Staphylococcus aureus, Streptococcus pyogenes, or their combinations. In nonbullous impetigo, methicillin­resistant strains (MRSA) of S. aureus are most often detected. For the colonization of staphylococcus and streptococcus, the necessary conditions are damage to the integrity of the skin and violation of the composition of the usual microflora of the skin. Patients with inflammatory skin diseases are most often colonized by S. aureus and are at high risk for developing MRSA infections. In bullous impetigo, the rash elements are represented by bullae which quickly burst with the formation of surface erosion and a yellow crust. Nonbullous impetigo is manifested by vesicles, pustules, crusts. Typically, impetigo is clinically diagnosed. Suspicion of MRSA occurs in cases of spontaneous abscess or cellulitis, or if lesions are not eliminated by the recommended initial treatment with antibiotics. Topical therapy is the first line of treatment for uncomplicated nonbullous and bullous impetigo. If the lesion is limited to a small area (up to 6 cm2), the treatment involves soaking the crusts, exfoliating them and applying antimicrobial ointments (fusidic acid or a combination of neomycin and bacitracin) (EBM Guidelines, 2018). With more diffuse lesions, systemic antibiotic therapy is prescribed. In treatment of patients with eczema, topical and systemic antimicrobials with topical steroids are used. The combination of the aminoglycoside antibiotic neomycin and the polypeptide antibiotic bacitracin is presented at the Ukrainian pharmaceutical market as Baneocin drug. This combination has a pronounced synergistic effect on S. aureus, S. pyogenes and P. aeryginosa. An important advantage of Baneocin is its availability in two forms (powder and ointment), which allows the use of this drug at different stages of the infection process.

Emulgel have emerged as one of the most interesting topical delivery system as it has dual control release system i.e gel and emulsion. Topical applications of drug offers many advantages for delivering drug directly to the site of action and deliver the drug for extended period of time at effected site. The major objective behind this formulation is to enhance topical delivery of hydrophobic drug (Fusidic acid) by formulating Fusidic acid emulgel by using carbopol 934 as gelling agent. In addition light liquid paraffin as oil, span 20 as emulsifier and propylene glycol as co-surfactant were selected for the preparation of emulgel. Fusidic acid is steroidal bacteriostatic agent produced from Fusidium coccineum fungus belongs to class of steroids but has no corticosteroids effect and which is useful for the treatment of number of infections. Fusidic acid binds to protein and ribosomes and inhibits bacterial protein synthesis. The prepared emulgel were evaluated for their physical appearance, pH determination, viscosity, spreadability, in-vitro drug release, antimicrobial activity, skin irritation study and stability. All the prepared emulgel showed acceptable physical properties. The best formulation E9 shows better drug release when compared to all formulation. Keywords: Emulgel, Carbopol 934, Topical formulation, Antimicrobial activity, optimization, Fusidic acid

New indole derivatives of fusidic acid were synthesized by using the Fischer reaction. The obtained compounds were screened in vitro for antibacterial activity and were found to inhibit the growth of Staphylococcus aureus (MRSA, strain ATCC 43300) at concentrations comparable to fusidic acid. The obtained indole derivatives of fusidic acid were also characterized by relatively low cytotoxicity and minimal hemolytic effect at the highest concentration that was tested (32 μg/ml).

Aims\ud \ud The aims of this study were to explore the development of bacterial resistance and cross‐resistance in four common human pathogens following realistic exposure to antibiotics found in over‐the‐counter (OTC) sore throat medicines: gramicidin, neomycin, bacitracin and tyrothricin.\ud Methods and Results\ud \ud Bacterial exposure to in‐use (concentration in the product before use) and diluted concentration (i.e. during use ) of antibiotic where conducted in broth for 24 h or until growth was visible. The changes in bacterial susceptibility profile before and after exposure was determined using standardized ISO microdilution broth. Antibiotic testing was performed according to EUCAST guidelines. We demonstrated that test bacteria were able to survive exposure to the in‐use concentrations of some antibiotics used in OTC medicines. Exposure to during use concentrations of bacitracin resulted in stable increase in minimal inhibitory concentration (MIC) (>8‐fold) in Staphylococcus aureus and Acinetobacter baumannii . Exposure to tyrothricin resulted in a stable increase in MIC (2·4‐fold) in Klebsiella pneumoniae , and exposure to neomycin resulted in a stable increase MIC (5000‐fold higher than the baseline) in Streptococcus pyogenes . Clinical cross‐resistance to other antibiotics (ciprofloxacin, fusidic acid, gentamicin, cefpodoxime, amoxicillin/clavulanic acid and cefotaxime) was also demonstrated following exposure to bacitracin or tyrothricin. Bacitracin exposure lead to a stable bacterial resistance after 10 passages.\ud Conclusions\ud \ud Our results indicate that OTC antibiotic medicines have the potential to drive resistance and cross‐resistance in vitro .\ud Significance and Impact of the Study\ud \ud Tackling antibiotic resistance is a high worldwide priority. It is widely accepted that the overuse and misuse of antibiotics increase the risk of the development and spread of antibiotic resistance within communities. A number of OTC sore throat products, widely available across the world for topical use in respiratory indications, contain locally delivered antibiotics. Our findings showed that these antibiotics in OTC medicines present a risk for emerging cross‐resistance in a number of bacterial respiratory pathogens.