One-Pot Reducing Agent-Free Synthesis of Silver Nanoparticles/Nitrocellulose Composite Surface Coating with Antimicrobial and Antibiofilm Activities.

Nitrocellulose with silver nanoparticle (AgNP/NC) composite was prepared in situ using Ag(CH3CO2) and nitrocellulose without any reducing agent. The composite materials synthesized were spray coated onto glass substrates to obtain thin films. The AgNPs/NC composites were characterized by ultraviolet-visible, Fourier transform infrared, X-ray photoelectron spectroscopy, scanning electron microscopy, and transmission electron microscopy. The antimicrobial activity of AgNPs/NC composite was investigated by tube method and time-kill kinetic studies against three microbial species, including Pseudomonas aeruginosa (ATCC 27853), Staphylococcus aureus (ATCC 25923), and Candida albicans (ATCC 10231). The antibiofilm activities were qualitatively determined against all three organisms. Prepared AgNPs/NC films exhibited good antimicrobial activity and significant inhibition of biofilm development against all three microbial species. The effective dispersion of AgNPs/NC in biofilm was responsible for the significant antibiofilm activity of the prepared material. The reported AgNPs/NC composite can be used as coating additive in bacteriocidal paint which can be applied onto surfaces such as in healthcare environments.

Synthesis, Characterization and Antimicrobial Activity of Garcinol Capped Silver Nanoparticles.

Garcinol, a well-known medicinal phytochemical, was extracted and isolated from the dried fruit rinds of Garcinia quaesita Pierre. In this study, garcinol has successfully used to reduce silver ions to silver in order to synthesize garcinol-capped silver nanoparticles (G-AgNPs). The formation and the structure of G-AgNPs were confirmed by UV-visible spectroscopy, transmission electron microscopy and Fourier transform infrared (FTIR) spectroscopy. The antimicrobial activity of garcinol and G-AgNPs were investigated by well diffusion assays, broth micro-dilution assays and time-kill kinetics studies against five microbial species, including Staphylococcus aureus (ATCC 25923), Pseudomonas aeruginosa (ATCC 27853), Escherichia coli (ATCC 25922), Candida albicans (ATCC 10231) and clinically isolated methicillin-resistant Staphylococcus aureus (MRSA). The formation of G-AgNPs is a promising novel approach to enhancing the biological activeness of silver nanoparticles, and to increase the water solubility of garcinol which creates a broad range of therapeutic applications.

Isolation and characterization of Leptospira interrogans from two patients with leptospirosis in Western Province, Sri Lanka.

Leptospirosis is an endemic infectious disease causing considerable morbidity and mortality in Sri Lanka; however, reports on the isolation of Leptospira from infected patients in Sri Lanka have been largely unavailable since the 1970s. Two isolates were obtained and characterized from 100 blood cultures from leptospirosis-suspected patients. Phylogenic analysis of partial flaB gene sequences identified the isolates as Leptospira interrogans. The patient serum samples from which Leptospira was isolated reacted with the Leptospira serogroups Sejroe and Canicola at a titre of 1 : 200. Exposure to domestic sewage and gutters filled with muddy water was suspected to be the source of infection in these two culture-positive patients. This study reports the successful isolation of pathogenic Leptospira from two patients in Western Province, Sri Lanka.

Enhanced antibacterial activity of TiO2 nanoparticle surface modified with Garcinia zeylanica extract.

BACKGROUND: The antibacterial activity of 21 nm TiO2 nanoparticles (NPs) and particles modified with Garcinia zeylanica (G. zeylanica) against Methicillin resistant Staphylococcus aureus was investigated in the presence and absence of light. RESULTS: Surface modification of TiO2 NPs with the adsorption of G. zeylanica extract, causes to shift the absorption edge of TiO2 NPs to higher wavelength. TiO2 NPs, G. zeylanica pericarp extract showed significant bactericidal activity which was further enhanced in contact with the TiO2 modified G. zeylanica extract. CONCLUSIONS: The antimicrobial activity was enhanced in the presence of TiO2 NPs modified with G. zeylanica and with longer contact time.

Aspergillus species: An emerging pathogen in onychomycosis among diabetics.

INTRODUCTION: Approximately, 33% patients with diabetes are afflicted with onychomycosis. In the past, nondermatophyte molds have been regarded as opportunistic pathogens; recently, Aspergillus species are considered as emerging pathogens of toenail infections. In Sri Lanka, the prevalence of Aspergillus species in onychomycosis among diabetics is not well documented. OBJECTIVE: To determine the proportion of Aspergillus onychomycosis, risk factors and knowledge among diabetics. MATERIALS AND METHODS: This was descriptive cross-sectional study. Three hundred diabetic patients were included. Clinical examinations of patients' toenails were performed by a clinical microbiologist. Laboratory identification was done, and pathogens were identified to the species level by morpho-physiological methods. All inferential statistics were tested at P < 0.05. RESULTS: Among clinically suspected patients, 85% (255/300) were mycologically confirmed to have onychomycosis. Aspergillus species were most commonly isolated n = 180 (71%) followed by dermatophytes, yeasts, and other molds n = 75 (29%). Of the patients having Aspergillus onychomycosis, 149 (83%) were in the > age group. In men, Aspergillus onycomycosis was seen in 82%. Among patients who had Aspergillus nail infection, 114 (63%) had diabetes for a period of > years. Among patients who were engaged in agricultural activities, 77% were confirmed to have infected nails due to Aspergillus species. CONCLUSION: Aspergillus niger was the most common pathogen isolated from toenail infection. Aspergillus species should be considered as an important pathogen in toenail onychomycosis in diabetic patients. Risk factors associated with Aspergillus onychomycosis were age, gender, duration of diabetes, length of exposure to fungi, and occupation.

Proportion of lower limb fungal foot infections in patients with type 2 diabetes at a tertiary care hospital in Sri Lanka.

BACKGROUND: Superficial fungal foot infection (SFFI) in diabetic patients increases the risk of developing diabetic foot syndrome. Sixteen percent of urban population is suffering from diabetes in Sri Lanka. As the diabetes patients are more prone to get fungal foot infections, early intervention is advisable owing to the progressive nature of the infection. There is no data on the prevalence of SFFIs in diabetic patients in Sri Lanka. OBJECTIVE: To determine the etiological agents causing SFFI in patients with type 2 diabetes. MATERIALS AND METHODS: Three hundred eighty five diabetic patients were included. Nail clippings and swabs were collected from the infected sites using the standard protocol. Laboratory identification was done and pathogens were identified to the species level by morpho physiological methods. RESULTS: Clinically 295 patients showed SFFI, of which 255 (86%) were mycologically confirmed for infection. Out of 236 direct microscopy (KOH) positives, 227 (96%) were culture positive. Two hundred and fifty one patients (98%) with SFFI had diabetes for more than 10 years. Of the patients with SFFIs 92% had >100 mg/dl FBS and 81% had >140 mg/dl PPBS levels and 80% had both elevated FBS and PPBS. Non-dermatophyte fungal species were the commonest pathogens followed by yeast and dermatophytes. CONCLUSION: Aspergillus niger was the commonest pathogen followed by Candida albicans. SFFIs were seen significantly with the increasing age, gender, duration of diabetes and with less controlled glycaemic level.