Human Skin Infections Research Articles

Suspected horse-to-human transmission of MRSA ST398.

Suspected horse-to-human transmission of MRSA ST398.

Surface and Extracellular Proteome of the Emerging Pathogen Corynebacterium ulcerans.

Corynebacterium ulcerans is an emerging pathogen, which is increasingly recognized as an etiological agent of diphtheria, but can also evoke ulcers of the skin and systemic infections in humans. Besides man, the bacteria can colonize a wide variety of different animals, including cattle and pet animals, which might serve as a reservoir for human infections. In this study, surface-located proteins and the exoproteome of two Corynebacterium ulcerans strains were analyzed, since these may have key roles in the interaction of the pathogen with host cells. Strain 809 was isolated from a fatal case of human respiratory tract infection, while strain BR-AD22 was isolated from a nasal swap of an asymptomatic dog. While a very similar pattern of virulence factors was observed in the culture supernatant and surface protein fractions of the two strains, proteome analyses revealed a higher stability of 809 cells compared to strain BR-AD22. During exponential growth, 17% of encoded proteins of strain 809 were detectable in the medium, while 38% of the predicted proteins encoded by the BR-AD22 chromosome were found. Furthermore, the data indicate differential expression of phospholipase D and a cell wall-associated hydrolase, since these were only detected in strain BR-AD22.

Early Lymphocyte Loss and Increased Granulocyte/Lymphocyte Ratio Predict Systemic Spread of Streptococcus pyogenes in a Mouse Model of Acute Skin Infection.

Background: Group A streptococci may induce lymphopenia, but the value of lymphocyte loss as early biomarkers for systemic spread and severe infection has not been examined systematically.Methods: We evaluated peripheral blood cell indices as biomarkers for severity and spread of infection in a mouse model of Streptococcus pyogenes skin infection, using two isolates of greatly differing virulence. Internal organs were examined histologically.Results: After subcutaneous inoculation, strain AP1 disseminated rapidly to peripheral blood and internal organs, causing frank sepsis. In contrast, seeding of internal organs by 5448 was mild, this strain could not be isolated from blood, and infection remained mostly localized to skin. Histopathologic examination of liver revealed microvesicular fatty change (steatosis) in AP1 infection, and examination of spleen showed elevated apoptosis and blurring of the white pulp/red pulp border late (40 h post infection) in AP1 infection. Both strains caused profound lymphopenia, but lymphocyte loss was more rapid early in AP1 infection, and lymphocyte count at 6 h post infection was the most accurate early marker for AP1 infection (area under the receiver operator curve [AUC] = 0.93), followed by the granulocyte/lymphocyte ratio (AUC = 0.89).Conclusions: The results suggest that virulence of S. pyogenes correlates with the degree of early lymphopenia and underscore the value of peripheral blood indices to predict severity of bacterial infections in mice. Early lymphopenia and elevated granulocyte/lymphocyte ratio merit further investigation as biomarkers for systemic spread of S. pyogenes skin infections in humans and, possibly, related pyogenic streptococci in humans and animals.

Microbiological survey of commercial tattoo and permanent makeup inks available in the United States.

Tattooing and use of permanent makeup (PMU) has dramatically increased over the last decade, with a concomitant increase in ink-related infections. The aim of this study was to determine whether micro-organisms are present, and if so, the number and their identification in the commercial tattoo and PMU inks available in the United States. We surveyed 85 unopened tattoo and PMU inks, purchased from 13 companies. We incubated 100μl of ink samples on trypticase soy agar plates for bacterial growth, 7H10 Middlebrook medium for mycobacterial growth, and Sabouraud dextrose medium for fungal growth. In total, 42 inks were contaminated with micro-organisms (49%). Thirty-three inks were contaminated with bacteria, 2 inks with fungi, and 7 inks had both bacterial and fungal growth. Mycobacteria were not detected in any of the examined tattoo and PMU inks. In 26 inks, microbial concentrations ranged between 101 and 103 CFU per ml, but higher counts (>103 CFU per ml) were recorded in 16 inks. We identified 83 bacteria by their 16S rDNA sequences, including 20 genera and 49 species. Strains of Bacillus spp. (53%) were dominant, followed by Lysinibacillus fusiformis (7%) and Pseudomonas aeruginosa (5%). Thirty-four (41%) possibly clinically relevant strains were identified, including P. aeruginosa, Dermacoccus barathri and Roseomonas mucosa, some of which have been previously reported to be associated with human skin infections. The results indicate that commercial tattoo and PMU inks on the US market surveyed in this study contain a wide range of micro-organisms, including pathogenic bacteria. Microbial contaminants in tattoo and PMU inks are an emerging safety concern for public health. This study provides evidence that microbial contamination of tattoo and PMU inks available in the United States is more common than previously thought and highlights the importance of monitoring these products for potentially pathogenic micro-organisms.

Transcriptome sequencing and analysis of zinc-uptake-related genes in Trichophyton mentagrophytes

BackgroundTrichophyton mentagrophytes is an important zoonotic dermatophytic (ringworm) pathogen; causing severe skin infection in humans and other animals worldwide. Fortunately, commonly used fungal skin disease prevention and treatment measures are relatively simple. However, T. mentagrophytes is primarily studied at the epidemiology and drug efficacy research levels, yet current study has been unable to meet the needs of clinical medicine.Zinc is a crucial trace element for the growth and reproduction of fungi and other microorganisms. The metal ions coordinate within a variety of proteins to form zinc finger proteins, which perform many vital biological functions. Zinc transport regulatory networks have not been resolved in T. mentagrophytes. The T. mentagrophytes transcriptome will allow us to discover new genes, particularly those genes involved in zinc uptake.ResultWe found T. mentagrophytes growth to be restricted by zinc deficiency; natural T. mentagrophytes growth requires zinc ions. T. Mentagrophytes must acquire zinc ions for growth and development.The transcriptome of T. mentagrophytes was sequenced by using Illumina HiSeq™ 2000 technology and the de novo assembly of the transcriptome was performed by using the Trinity method, and functional annotation was analyzed. We got 10,751 unigenes. The growth of T. mentagrophytes is severely inhibited and there were many genes showing significant up regulation and down regulation respectively in T. mentagrophytes when zinc deficiency. Zinc deficiency can affect the expression of multiple genes of T. mentagrophytes. The effect of the zinc deficiency could be recovered in the normal medium. And we finally found the zinc-responsive activating factor (ZafA) and speculated that 4 unigenes are zinc transporters. We knocked ZafA gene by ATMT transformation in T. mentagrophytes, the result showed that ZafA gene is very important for the growth and the generation of conidia in T. mentagrophytes. The expression of 4 zinc transporter genes is potentially regulated by the zinc-responsive activating factor. The data of this study is also sufficient to be used as a support to study T. mentagrophytes.ConclusionWe reported the first large transcriptome study carried out in T. mentagrophytes where we have compared physiological and transcriptional responses to zinc deficiency, and analyzed the expression of genes involved in zinc uptake. The study also produced high-resolution digital profiles of global genes expression relating to T. mentagrophytes growth.

MALDI-TOF MS analysis of bovine and zoonotic Trichophyton verrucosum isolates reveals a distinct peak and cluster formation of a subgroup with Trichophyton benhamiae.

The zoophilic dermatophyte Trichophyton verrucosum is the most important causative agent of bovine dermatophytosis. Additionally, it causes profound and poorly healing skin infections in humans indicating the high zoonotic potential. The objective of this study was to establish differentiation of T. verrucosum from other dermatophytes by mass spectrometry and to identify distinct features of the mass spectra. Matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) was successful for identification of this pathogen only after extension of the database of the manufacturer with spectra from T. verrucosum strains, which were identified as such by sequencing of the internal transcribed spacer (ITS) region. MALDI-TOF MS analysis was conducted with 46 field isolates from cattle, two live vaccine strains, and 10 isolates from humans identified as T. verrucosum by sequence analysis of the ITS region. The results suggest a very good agreement of both methods. Comparison with the mass spectra of 68 strains of other keratinophilic fungi revealed that most T. verrucosum wild-type isolates showed a characteristic peak at 7950-7954m/z, which was missing in the spectra of other keratinophilic fungi and the live vaccine strains. The spectra of T. verrucosum were most similar to the spectra of T. benhamiae, an emerging zoophilic dermatophyte. In summary, MALDI-TOF MS is a powerful and reliable tool to identify T. verrucosum.

Aedes Aegypti saliva enhances chikungunya virus replication in human skin fibroblasts via inhibition of the type I interferon signaling pathway

Chikungunya virus (CHIKV) transmission occurs through the bite of an infected Aedes mosquito which injects virus-containing saliva into the skin of the human host during blood feeding. In the present study, we have determined the effect of Aedes aegypti saliva on CHIKV replication in human skin fibroblasts, a major cell type for viral entry, which mimics the events that occur during natural transmission. A significant increase in the expression of viral transcripts and infectious viral particles was observed in fibroblasts infected with CHIKV in the presence of saliva, as compared with those infected with virus alone. CHIKV-infected human fibroblasts were found to express significantly increased levels of various type I IFN-responsive genes, as demonstrated by specific PCR array analysis. In contrast, the expression of these genes was markedly decreased in cells infected with CHIKV in the presence of mosquito saliva. Moreover, Western blotting analysis revealed that STAT2 and its phosphorylated form were down-regulated in the presence of mosquito saliva. Our data demonstrate for the first time the significance of Aedes aegypti saliva in promoting CHIKV infection via down-regulation of several type I IFN-responsive genes in infected human skin fibroblasts via the JAK-STAT signaling pathway.

Preliminary investigations into developing all-D Omiganan for treating Mupirocin-resistant MRSA skin infections.

Staphylococcus aureus is the primary pathogen responsible for the majority of human skin infections, and meticillin-resistant S.aureus (MRSA) currently presents a major clinical concern. The overuse of Mupirocin, the first-line topical antibacterial drug over 30years, has led to the emergence of Mupirocin-resistant MRSA, creating a clinical concern. The antimicrobial peptide Omiganan was touted to be a promising antibacterial drug candidate due to its rapid membrane-disrupting bactericidal mode of action, entering clinical trials in 2005 as a topical gel to prevent catheter site infections. However, drug development ceased in 2009 due to a lack of efficacy. We postulate this to be due to proteolytic degradation caused by endogenous human skin proteases. Herein, we tested our hypothesis using Omiganan and its all-D enantiomer in a human skin protease stability assay, followed by anti-MRSA activity assay against of a panel of clinical MRSA isolates, a bactericidal/static determination and a time-kill assay to gauge all-D Omiganan's potential for further topical antibacterial drug development.

Antimicrobial and antioxidant potentials of biosynthesized colloidal zinc oxide nanoparticles for a fortified cold cream formulation: A potent nanocosmeceutical application

Nanocosmeceuticals are promising applications of nanotechnology in personal care industries. Zinc oxide is an inorganic material that is non-toxic and skin compatible with self-cleansing and microbicidal properties. Herein, exploitation of colloidal zinc oxide nanoparticles (ZnONps) as potent biomaterial for a topical formulation of cosmetic and dermatological significance is employed. ZnONps were green synthesized using environmentally benign Adhatoda vasica leaf extract and characterized by UV–Vis absorption spectroscopy, Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), dynamic light scattering (DLS), high-resolution transmission electron microscopy (HR-TEM) and energy-dispersive X-ray spectroscopy (EDX). The results reveal that the biosynthesized ZnONps exhibit an absorption peak at 352nm. XRD and HR-TEM analyses confirm the hexagonal wurtzite structure of ZnONps with particle size of about 10nm to 12nm. Elemental analysis by EDX confirms the presence of zinc and oxygen. Zeta potential of −24.6mV affirms the stability of nanoparticles. The antibacterial and antifungal activities of biosynthesized ZnONps exhibit mean zone of inhibition from 08.667±0.282 to 21.666±0.447 (mm) and 09.000±0.177 to 19.000±0.307 (mm) respectively, in a dose-dependent manner. The IC50 value exerted from the antioxidant activity of ZnONps is found to be 139.27μgmL−1. ZnONps infused cold cream formulation of microbicidal and antioxidant properties was further tested against clinical skin pathogens. The nano-based cold cream exhibited significant inhibitory action against Candida sp., which showed resistance against a commercial antifungal cream (2%). Therefore, this study demonstrates the exploitation of ZnONps as promising colloidal drug carriers in cosmeceuticals that can significantly alleviate human skin infections and oxidative stress induced cellular damage.

Trichophyton verrucosum infection in livestock in the Chitral district of Pakistan.

Trichophyton verrucosum belongs to the dermatophyte fungi, closely related organisms that cause skin infections in animals and humans. T. verrucosum infection has been reported in livestock and people in different countries from all continents. Human cases have been reported in different areas of Pakistan, but there is little information about the animal source of the fungus. Dermatological specimens collected in the Chitral district of Pakistan for a study on mange in livestock were retrospectively analyzed for the presence of T. verrucosum. In total, 5,873 animals (1,087 cows, 2,033 goats, and 2,753 sheep) were screened for evidence of dermatological lesions during two surveys performed in the summer and winter seasons. Skin scrapings collected from animals with lesions were analyzed by direct microscopic examination after digestion in sodium hydroxide and a real-time polymerase chain reaction (PCR) targeting pathogenic Trichophyton species. At microscopy, samples from 18 cows (1.6%), 3 sheep (0.1%), and 4 goats (0.2%) were positive for fungal elements consistent with T. verrucosum. PCR confirmed the microscopy results. The prevalence was lower than that reported in other countries in intensive breeding farms. Results agree with the literature regarding factors affecting T. verrucosum diffusion, i.e., infection was more prevalent in cattle, especially in younger animals during the winter season. This study reports, for the first time, the presence of T. verrucosum in livestock in Pakistan. A better knowledge of the animal role in the spread of this fungus may allow the adoption of more efficient control measures and prophylaxis.

Development of hydroxyapatite-chitosan gel sunscreen combating clinical multidrug-resistant bacteria

The several harmful effects on infected human skin resulting from exposure to the sun's UV radiation generate an interest in the development of a multifunctional hydroxyapatite-chitosan (HAp-chitosan) gel that works as an antibacterial sunscreen agent for skin care. In this work, HAp-chitosan gel was synthesized via coprecipitation method by dissolving chitosan in phosphoric acid and adding HAp. The characteristics of HAp-chitosan composite were investigated by conventional techniques, such as XRD, FTIR, and SEM techniques, while its sunscreen property was investigated by UV-spectroscopy. In addition to the influence of the gel on bacterial cell morphology, the antibacterial activity of HAp-chitosan gel against clinical multidrug resistant skin pathogens, such as Staphylococcus aureus, Klebsiella pneumoniae, and Pseudomonas aeruginosa has been studied. The results revealed the formation of HAp-chitosan gel having nanosized particles, which confers protection against UV-radiation. The antibacterial activity records showed that chitosan-HAp gel exhibits a significant effect on the growth and ultrastructure of multi-drug resistant bacterial activities. Therefore, the chitosan-HAp gel is promising for skin health care as an antibacterial sunscreen.

Determination of ultra-morphological changes of Trichophyton rubrum treated with hydroxychavicol

Introduction: Trichophyton rubrum is a common pathogenic fungal species that is responsible for causing infection of human skin, hair and nail. The antifungal-resistant strains however, complicate the treatment regime. Hydroxychavicol (HC) is one of the main compounds from the Piper betel leaf that have antifungal potential and its mechanism of action has yet to be studied. This study was carried out to determine the antifungal properties of HC against Trichophyton rubrum using transmission electron microscope (TEM) on gross and ultrastructure of Trichophyton rubrum hypha. Methods: Broth dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of HC and miconazole (MI) against the Trichophyton rubrum (ATCC 28188). Trichophyton rubrum was treated with HC and MI at concentrations of 1.25, 2.5, 5 and 10 mg/mL for 1, 3, 5 and 7 days continuously. Results: The MIC results of the HC and MI against Trichophyton rubrum were 0.00048 mg/mL and 0.000061 mg/mL respectively. MFC results showed 0.0019 mg/mL for HC and 0.000061 mg/mL for MI. Microscopically, the fungi structures became more severely damaged at increasing treatment duration. The cell wall of the fungi treated with HC showed a rough surface, shrinkage and demolition similar to that of the MI treated group. The fungi organelles were also demolished and disorganized. Conclusions: This study reveals that HC has the ability to inhibit Trichophyton rubrum growth and it has the potential to be an antifungal agent especially in treating dermatitis.

Genome Anatomy of Pyrenochaeta unguis-hominis UM 256, a Multidrug Resistant Strain Isolated from Skin Scraping.

Pyrenochaeta unguis-hominis is a rare human pathogen that causes infection in human skin and nail. P. unguis-hominis has received little attention, and thus, the basic biology and pathogenicity of this fungus is not fully understood. In this study, we performed in-depth analysis of the P. unguis-hominis UM 256 genome that was isolated from the skin scraping of a dermatitis patient. The isolate was identified to species level using a comprehensive multilocus phylogenetic analysis of the genus Pyrenochaeta. The assembled UM 256 genome has a size of 35.5 Mb and encodes 12,545 putative genes, and 0.34% of the assembled genome is predicted transposable elements. Its genomic features propose that the fungus is a heterothallic fungus that encodes a wide array of plant cell wall degrading enzymes, peptidases, and secondary metabolite biosynthetic enzymes. Antifungal drug resistance genes including MDR, CDR, and ERG11/CYP51 were identified in P. unguis-hominis UM 256, which may confer resistance to this fungus. The genome analysis of P. unguis-hominis provides an insight into molecular and genetic basis of the fungal lifestyles, understanding the unrevealed biology of antifungal resistance in this fungus.

Peptides from Tetraspanin CD9 Are Potent Inhibitors of Staphylococcus Aureus Adherence to Keratinocytes.

Staphylococcus aureus is one of the primary causative agents of skin and wound infections. As bacterial adherence is essential for infection, blocking this step can reduce invasion of host tissues by pathogens. An anti-adhesion therapy, based on a host membrane protein family, the tetraspanins, has been developed that can inhibit the adhesion of S. aureus to human cells. Synthetic peptides derived from a keratinocyte-expressed tetraspanin, CD9, were tested for anti-adhesive properties and at low nanomolar concentrations were shown to inhibit bacterial adhesion to cultured keratinocytes and to be effective in a tissue engineered model of human skin infection. These potential therapeutics had no effect on keratinocyte viability, migration or proliferation, indicating that they could be a valuable addition to current treatments for skin infection.

Antibiotic susceptibility and genomic variations in Staphylococcus aureus associated with Skin and Soft Tissue Infection (SSTI) disease groups.

BackgroundStaphylococcus aureus is associated with human skin and soft tissue infections (SSTIs); however, the involvement of virulence factors in different clinical presentations is unclear.MethodsWe analyzed methicillin-resistant S. aureus (MRSA) and methicillin-sensitive S. aureus (MSSA) strains from Taiwan to determine correlations among the clinical characteristics of SSTIs, antimicrobial susceptibility and virulence factors of S. aureus with specific genetic backgrounds.ResultsWe identified 177 MRSA isolates and 130 MSSA isolates among the 307 SSTI-associated S. aureus isolates. Hospital-acquired (HA)- and community-acquired (CA)-MRSA isolates accounted for 61.6 % and 38.4 % of the isolates, respectively. Clinical presentations in SSTI patients differed significantly for the disease groups. Deep-seated MRSA infections presented with higher amputation rate than MSSA infections. MRSA isolates were all susceptible to linezolid, teicoplanin, and vancomycin, and >94 % of isolates were erythromycin- and clindamycin-resistant. Staphylococcal cassette chromosome (SCCmec) types IV, V, and VII were the most frequent in the CA-MRSA group (n = 68); types III, IV and V were the most frequent in the HA-MRSA group (n = 109). Panton-Valentine leukocidin (PVL) genes were significantly more frequent in CA-MRSA strains (75.0 %) than in HA-MRSA (33.0 %) and MSSA (24.6 %) and were found in 66.7 % (74/111) strains isolated from the abscess group. Exfoliatin A genes were more common in catheter-related exit-site MSSA infections (37.5 %) compared with other MSSA disease groups (P < 0.05). Exfoliatin B and superantigen exotoxin genes were uncommon in all SSTI disease types. Pulsotypes A (ST239), C, and D (ST59) were the predominant MRSA genotypes in deep-seated infections.ConclusionsIf not treated appropriately, deep-seated MRSA-associated infections present with higher amputation rates than deep-seated MSSA-associated infections. PVL-positive MRSA strains caused more frequently pus-forming lesions and less bacteremia and invasive diseases. Methods for discriminating CA-MRSA from HA-MRSA strains are now unreliable due to circulation of both ST 239 and ST 59 strains in the community and nosocomial settings. Initial antibiotic treatments should consider MRSA for patients with SSTIs in areas where MRSA is prevalent.

The Role of Staphylococcus aureus Virulence Factors in Skin Infection and Their Potential as Vaccine Antigens

Staphylococcus aureus (S. aureus) causes the vast majority of skin and soft tissue infections (SSTIs) in humans. S. aureus has become increasingly resistant to antibiotics and there is an urgent need for new strategies to tackle S. aureus infections. Vaccines offer a potential solution to this epidemic of antimicrobial resistance. However, the development of next generation efficacious anti-S. aureus vaccines necessitates a greater understanding of the protective immune response against S. aureus infection. In particular, it will be important to ascertain if distinct immune mechanisms are required to confer protection at distinct anatomical sites. Recent discoveries have highlighted that interleukin-17-producing T cells play a particularly important role in the immune response to S. aureus skin infection and suggest that vaccine strategies to specifically target these types of T cells may be beneficial in the treatment of S. aureus SSTIs. S. aureus expresses a large number of cell wall-anchored (CWA) proteins, which are covalently attached to the cell wall peptidoglycan. The virulence potential of many CWA proteins has been demonstrated in infection models; however, there is a paucity of information regarding their roles during SSTIs. In this review, we highlight potential candidate antigens for vaccines targeted at protection against SSTIs.

Genome Sequence of Bacillus pumilus Strain Bonn, Isolated from an Anthrax-Like Necrotic Skin Infection Site of a Child

We report the draft genome sequence of Bacillus pumilus strain Bonn associated with human skin infection. B. pumilus Bonn was isolated from a carbuncle-like necrotic site, resembling cutaneous anthrax, on the back of the hand of a 10-year-old child.

Evidence of In Vivo Existence of Borrelia Biofilm in Borrelial Lymphocytomas.

Lyme borreliosis, caused by the spirochete Borrelia burgdorferi sensu lato, has grown into a major public health problem. We recently identified a novel morphological form of B. burgdorferi, called biofilm, a structure that is well known to be highly resistant to antibiotics. However, there is no evidence of the existence of Borrelia biofilm in vivo; therefore, the main goal of this study was to determine the presence of Borrelia biofilm in infected human skin tissues. Archived skin biopsy tissues from borrelial lymphocytomas (BL) were reexamined for the presence of B. burgdorferi sensu lato using Borrelia-specific immunohistochemical staining (IHC), fluorescent in situ hybridization, combined fluorescent in situ hybridization (FISH)–IHC, polymerase chain reaction (PCR), and fluorescent and atomic force microscopy methods. Our morphological and histological analyses showed that significant amounts of Borrelia-positive spirochetes and aggregates exist in the BL tissues. Analyzing structures positive for Borrelia showed that aggregates, but not spirochetes, expressed biofilm markers such as protective layers of different mucopolysaccharides, especially alginate. Atomic force microscopy revealed additional hallmark biofilm features of the Borrelia/alginate-positive aggregates such as inside channels and surface protrusions. In summary, this is the first study that demonstrates the presence of Borrelia biofilm in human infected skin tissues.

In vitro and ex vivo infection models help assess the molecular aspects of the interaction of Trichophyton rubrum with the host milieu.

Dermatophytes are fungal pathogens that cause cutaneous infections such as onychomycosis and athlete's foot in both healthy and immunocompromised patients.Trichophyton rubrum is the most prevalent dermatophyte causing human nail and skin infections worldwide, and because of its anthropophilic nature, animal infection models are limited. The purpose of this work was to compare the expression profile of T. rubrum genes encoding putative virulence factors during growth in ex vivo and in vitro infection models. The efficiency of the ex vivo skin infection model was confirmed by scanning electron microscopy (SEM), which showed that the conidia had produced hyphae that penetrated into the epidermis. Quantitative RT-PCR (qRT-PCR) analysis showed that the expression of some genes is modulated in response to the infection model used, as compared to that observed in cells grown in glucose-containing media. We concluded that ex vivo infection models help assess the molecular aspects of the interaction of T. rubrum with the host milieu, and thus provide insights into the modulation of genes during infection.

Antimicrobial Activity of Chromolaena odorata Extracts against Bacterial Human Skin Infections

&lt;p&gt;Leaf, stem and root of &lt;em&gt;Chromolaena odorata&lt;/em&gt; were extracted by maceration extraction method using water, ethanol, methanol and hexane as solvents. The average percentage yield of leaf extracts in water (12.16 ± 0.13%), ethanol (8.42 ± 0.115%), methanol (10.45 ± 0.012%) and hexane (2.37 ± 0.215%) were significantly higher compared with stem and root extracts using the same solvents. All extracts were tested for antimicrobial activity against ten bacterial strains associated with human skin infections. Leaf extracts with ethanol, methanol and hexane solvents gave the best inhibitory activity against six gram-positive bacterial strains (&lt;em&gt;Bacillus cereus&lt;/em&gt; TISTR 687, &lt;em&gt;Enterococcus faecalis &lt;/em&gt;TISTR 379, &lt;em&gt;Staphylococcus epidermidis &lt;/em&gt;TISTR 518, &lt;em&gt;Staphylococcus aureus &lt;/em&gt;TISTR 1466, &lt;em&gt;Streptococcus pyogenes &lt;/em&gt;ATCC 19615 and &lt;em&gt;Propionibacterium acnes&lt;/em&gt; DMST 14916) and one gram-negative bacterial strain (&lt;em&gt;Proteus vulgaris &lt;/em&gt;ATCC 13315). The hexane stem extract showed greater inhibitory activity against &lt;em&gt;Pseudomonas aeruginosa &lt;/em&gt;ATCC 27853(15.3±0.5 mm), &lt;em&gt;B. cereus&lt;/em&gt; TISTR 687(14.6±0.8 mm) and &lt;em&gt;Klebsiella pneumoniae&lt;/em&gt; TISTR 1843 (14.0±1.0 mm), while hexane root extract showed high inhibitory activity against &lt;em&gt;Enterococcus faecalis &lt;/em&gt;TISTR 379 (14.5±0.9 mm) and &lt;em&gt;Kleb. pneumoniae&lt;/em&gt; TISTR 1843 (14.7±0.6 mm). The lowest minimum inhibitory concentration (MIC) of the ethanolic leaf extract was 0.81 mg/mL against &lt;em&gt;Staph. aureus &lt;/em&gt;TISTR 1466, followed by methanolic and hexane leaf extracts with equal MIC of 1.62 mg/mL against both &lt;em&gt;Staph. aureus &lt;/em&gt;TISTR 1466 and &lt;em&gt;Strep. pyogenes &lt;/em&gt;ATCC 19615. The antimicrobial activity of the methanolic leaf extract of &lt;em&gt;C. odorata &lt;/em&gt;was correlated with the amount of both total phenolic and flavonoid compounds. The results obtained suggest that the ethanolic, methanolic and hexane leaf extracts could be developed to treat bacterial skin infections. The hexane was sutiable solvent for extraction of the stem and root parts of &lt;em&gt;C. odorata&lt;/em&gt;.&lt;/p&gt;