Identification bacteria associated with Haliclona sp. sponges from Enggano Island, Indonesia with antimicrobial activity against human pathogens

Aims@#Antimicrobial compounds are bioactive compounds that have ability to inhibit microbial growth activities. This study aimed to screen and identify bacteria associated with Haliclona sp. sponges from Enggano Island, Indonesia that had potential to produce antimicrobial compounds against Escherichia coli, Candida albicans and Staphylococcus epidermidis.@*Methodology and results@#The method used to screen and identify bacteria in this study including screening assay, morphological identification, Gram staining and spore staining method, biochemical tests and molecular identification based on 16S rRNA gene. This study resulted 16 isolates which were successfully isolated from Haliclona sp. According to screening assay, 5 isolates could potentially produce antimicrobial compounds coded as HEBS1, HEBS3, HEBS6, HEBB2 and HEBB3. Based on Gram staining, spore staining, biochemical test and molecular identification results, HEBS1 had proximity to Brachybacterium paraconglomeratum, HEBS3 had proximity to Kocuria palustris, HEBS6 had proximity to Psychrobacter pasificensis, HEBB2 had proximity to Bacillus aryabhattai, and HEBB3 had proximity to Bacillus toyonensis.@*Conclusion, significance and impact of study@#From 16 isolates that successfully isolated, there were 5 isolates that could potentially produce antimicrobial compounds against Escherichia coli, Staphylococcus epidermidis and Candida albicans. These isolates can be served as antimicrobial compounds producer. However, identification and purification of these antimicrobial compounds are needed to be done before applied it for medicine in the future.

Antifungal activity of liriodenine on agents of systemic mycoses, with emphasis on the genus Paracoccidioides

Endemic systemic mycoses remain a health challenge, since these opportunistic diseases are increasingly infecting immunosuppressed patients. The simultaneous use of antifungal compounds and other drugs to treat infectious or non-infectious diseases has led to several interactions and undesirable effects. Thus, new antifungal compounds should be investigated. The present study aimed to evaluate the activity of liriodenine extracted from Annona macroprophyllata on agents of systemic mycoses, with emphasis on the genus Paracoccidioides. Methods: The minimum inhibitory concentration (MIC) and minimum fungicide concentration (MFC) were determined by the microdilution method. The cellular alterations caused by liriodenine on a standard P. brasiliensis (Pb18) strain were evaluated by transmission and scanning electron microscopy. Results: Liriodenine was effective only in 3 of the 8 strains of the genus Paracoccidioides and in the Histoplasma capsulatum strain, in a very low concentration (MIC of 1.95 µg.mL-1); on yeasts of Candida spp. (MIC of 125 to 250 µg.mL-1), including C. krusei (250 µg.mL-1), which has intrinsic resistance to fluconazole; and in Cryptococcus neoformans and Cryptococcus gattii (MIC of 62.5 µg.mL-1). However, liriodenine was not effective against Aspergillus fumigatus at the studied concentrations. Liriodenine exhibited fungicidal activity against all standard strains and clinical isolates that showed to be susceptible by in vitro tests. Electron microscopy revealed cytoplasmic alterations and damage to the cell wall of P. brasiliensis (Pb18). Conclusion: Our results indicate that liriodenine is a promising fungicidal compound that should undergo further investigation with some chemical modifications.(AU)

Antimicrobial Producing Bacteria Isolated from Tropical Peat Swamp Soil

Aims: The aims of this study were to isolate and characterize antimicrobial producing bacteria from tropical peat swamp forest soils. Methodology and results: Bacteria isolated from peat soil were screened for antimicrobial properties via agar overlay assay. Broth microdilution was performed using crude-cell free supernatant (CCFS) to determine the minimum inhibitory concentration (MIC). One isolate was selected due to its broad spectrum activity and identified as Burkholderia spp. with a maximum identity of 99% via 16s rRNA gene PCR. This isolate was able to produce antimicrobials that were active against several Gram positive bacteria, Gram negative bacteria and also yeast. The antimicrobial activity of the CCFS was stable at a pH range of 1 to 11, temperatures of −20 °C to 80 °C, and after treatment with several proteolytic enzymes: α-chymotrypsin, proteinase K and trypsin, indicating that the antimicrobial produced might not be proteinaceous in nature. It is possible that the isolate can produce polyketides, a type of antimicrobial compound produced by Burkholderia known to be resistant to proteolytic enzymes. However, further work needs to be done to confirm this. Conclusion, significance and impact of study: The presence of antimicrobial producing bacteria signified that tropical peat swamps are indeed a potential source for antimicrobials to combat infections.

Presence of enterotoxigenic Staphylococcus aureus in artisan fruit salads in the city of San Luis, Argentina

An increase in the consumption of fruit juices and minimally processed fruits salads has been observed in recent years all over the world. In this work, the microbiological quality of artisan fruit salads was analysed. Faecal coliforms, Salmonella spp, Shigella spp, Yersinia enterocolitica and Escherichia coli O157:H7 were not detected; nevertheless, eleven strains of Staphylococcus aureus were isolated. By multiplex PCR, all isolates showed positive results for S. aureus 16S rRNA gene and 63.6% of them were positive for sea gene. Furthermore, PCR sea positive strains were able to produce the corresponding enterotoxin. Finally, the inactivation of these strains in fruit salads by nisin, lysozyme and EDTA, was studied. EDTA produced a total S. aureus growth inhibition after 60 h of incubation at a concentration of 250 mg/L. The presence of S. aureus might indicate inadequate hygiene conditions during salad elaboration; however, the enterotoxigenicity of the strains isolated in this study, highlights the risk of consumers' intoxication. EDTA could be used to inhibit the growth of S. aureus in artisan fruit salads and extend the shelf life of these products.

Novel pharmaceutical molecules against emerging resistant gram-positive cocci

INTRODUCTION: methicillin- and also vancomycin (glycopeptide)-resistant Gram-positive organisms have emerged as an increasingly problematic cause of hospital-acquired infections, also spreading into the community. Vancomycin (glycopeptide) resistance has emerged primarily among Enterococci, but the MIC values of vancomycin for the entire Staphylococcus species are also increasing worldwide. MATERIAL AND METHODS: the aim of our review is to evaluate the efficacy and tolerability of newer antibiotics with activity against methicillin-resistant and glycopeptide-resistant Gram-positive cocci, on the ground of our experience at a tertiary care metropolitan Hospital, and the most recent literature evidences in this field. RESULTS: Quinupristin-dalfopristin, linezolid, daptomycin, and tigecycline show an excellent in vitro activity, comparable to the activity of vancomycin and teicoplanin for methicillin-resistant staphylococci, and superior to the one that vancomycin for vancomycin-resistant isolates. Dalbavancin, televancin, and oritavancin are new lipoglycopeptide agents with excellent activity against Gram-positive cocci, and have superior pharmacodynamics properties compared to vancomycin. We review the bacterial spectrum, clinical indications and practical use, pharmacologic properties, and expected adverse events and contraindications associated with each of these novel antimicrobial agents, compared with the present standard of care. DISCUSSION: linezolid activity is substantially comparable to that of vancomycin in patients with methicillin-resistant Staphylococcus aureus (MRSA) pneumonia, although its penetration into the respiratory tract is exceptionally elevated. Tigecycline has activity against both Enterococus species and MRSA; it is also active against a broad spectrum of Enterobacteriaceae and anaerobes, which allows for use intraabdominal, diabetic foot and surgical infections. Daptomycin has a rapid bactericidal activity for ...