Streptomyces lunalinharesii 235 prevents the formation of a sulfate-reducing bacterial biofilm

ABSTRACT Streptomyces lunalinharesii strain 235 produces an antimicrobial substance that is active against sulfate reducing bacteria, the major bacterial group responsible for biofilm formation and biocorrosion in petroleum reservoirs. The use of this antimicrobial substance for sulfate reducing bacteria control is therefore a promising alternative to chemical biocides. In this study the antimicrobial substance did not interfere with the biofilm stability, but the sulfate reducing bacteria biofilm formation was six-fold smaller in carbon steel coupons treated with the antimicrobial substance when compared to the untreated control. A reduction in the most probable number counts of planktonic cells of sulfate reducing bacteria was observed after treatments with the sub-minimal inhibitory concentration, minimal inhibitory concentration, and supra-minimal inhibitory concentration of the antimicrobial substance. Additionally, when the treated coupons were analyzed by scanning electron microscopy, the biofilm formation was found to be substantially reduced when the supra-minimal inhibitory concentration of the antimicrobial substance was used. The coupons used for the biofilm formation had a small weight loss after antimicrobial substance treatment, but corrosion damage was not observed by scanning electron microscopy. The absence of the dsrA gene fragment in the scraped cell suspension after treatment with the supra-minimal inhibitory concentration of the antimicrobial substance suggests that Desulfovibrio alaskensis was not able to adhere to the coupons. This is the first report on an antimicrobial substance produced by Streptomyces active against sulfate reducing bacteria biofilm formation. The application of antimicrobial substance as a potential biocide for sulfate reducing bacteria growth control could be of great interest to the petroleum industry.

Actividad antimicrobiana del ácido acético 5% y el cepillo Colgate 360° antibacterial®: un estudio in vitro / Antimicrobial activity of acetic acid and Colgate 360° antibacterial toothbrush®: an in vitro study

Introducción: el cepillo dental se convierte en una fuente potencial de patógenos orales cuando no se hace un proceso de desinfección después de su uso, sobre todo en pacientes con infecciones en el sistema estomatognático o poblaciones que no hacen recambio frecuente de este instrumento. El objetivo de este estudio fue comparar la actividad antimicrobiana del ácido acético 5% con la del cepillo Colgate 360° antibacterial® como posibles estrategias en la desinfección del cepillo dental. Métodos: se utilizaron 48 cabezas de cepillos dentales que fueron inoculadas con Staphylococcus aureus, Streptococcus mutans y Cándida albicans separadamente. Las cabezas fueron divididas en tres grupos: cabezas tratadas con ácido acético 5% (vinagre blanco casero, La Constancia®) por 10 minutos, cabezas 360° con actividad antibacterial y controles tratados con solución salina. Posteriormente se hizo recuento de UFC/ml de los microorganismos remanentes en las cabezas de cepillos después del tratamiento o tiempo de acción. Resultados: frente a S. aureus, el cepillo Colgate 360° antibacterial® mostró mejor efecto antimicrobiano que el ácido acético 5% (PI: 72,11 5). Los dos tratamientos evaluados mostraron capacidad similar para eliminar S. mutans de las cabezas de cepillos (p > 0,05); mientras que para C. albicans, el mejor efecto antimicrobiano lo obtuvo el ácido acético 5% (PI: 99,9%). Conclusión: in vitro el vinagre blanco de uso casero y el cepillo Colgate 360° antibacterial® eliminan microorganismos que colonizan cabezas de cepillos dentales como S. aureus, S. mutans y C. albicans, convirtiéndose en alternativas en diversas poblaciones para mantener el cepillo dental libre de microorganismos.

Introduction: toothbrushes may become a potential source of oral pathogens when not properly disinfected once they have been used, especially in patients with infections of the stomatognathic system or among populations that do not often replace this instrument. The goal of this study was to compare the antimicrobial activity of 5% acetic acid with that of Colgate 360º antibacterial toothbrush® as possible strategies for toothbrush disinfection. Methods: this study included 48 toothbrush heads that were separately inoculated with Staphylococcus aureus, Streptococcus mutans and Cándida albicans. The heads were sorted out into three groups: heads treated with 5% acetic acid (white domestic vinegar, La Constancia®) for 10 minutes; 360º toothbrush heads with antibacterial properties, and control heads treated with saline solution. This was followed by calculations of CFU/ml of the microorganism remaining in the heads after treatment or time of action. Results: in presence of S. aureus, Colgate 360º antibacterial toothbrush® proved to have better antimicrobial activity than 5% acetic acid (PI:72.11 5). The two assessed treatments showed a similar capacity to eradicate S. mutans from the brush heads (p> 0,05); concerning C. albicans, the best antimicrobial activity was observed in the 5% acetic acid (PI: 99,9%). Conclusion: in vitro, both white domestic vinegar and Colgate 360º antibacterial toothbrush® remove microorganisms colonizing toothbrush heads, such as S.aureus, S. mutans y C. albicans, and are therefore considered good alternatives for keeping toothbrushes free of microoorganisms among several populations.

Marine Pseudomonas putida: a potential source of antimicrobial substances against antibiotic-resistant bacteria

Bacteria isolated from marine sponges found off the coast of Rio de Janeiro, Brazil, were screened for the production of antimicrobial substances. We report a new Pseudomonas putida strain (designated P. putida Mm3) isolated from the sponge Mycale microsigmatosa that produces a powerful antimicrobial substance active against multidrug-resistant bacteria. P. putida Mm3 was identified on the basis of 16S rRNA gene sequencing and phenotypic tests. Molecular typing for Mm3 was performed by RAPD-PCR and comparison of the results to other Pseudomonas strains. Our results contribute to the search for new antimicrobial agents, an important strategy for developing alternative therapies to treat infections caused by multidrug-resistant bacteria.

The fungi from anemones in the intertidal zone of Qingdao sea area and the antimicrobial substance they produced / 中国海洋药物

In this study,amount to 23 strains of marine fungi had been isolated from anemones which inhabited on the rocks of the intertidal zone of Qingdao sea area,and the bioactivity of antimicroorganism had been determined.There are 15 strains of fungi from Anthopleura Qingdaoenisis Pei belong to 4 different genus of Fungi Imperfecti,and 8 strains of fungi from A.Midori fall respectively into 6 genus of fungi inperfecti.Among the 23 strains of fungi isolated,there are 3 strains that can inhibit the pathomycete of plants.