Biofilm inhibition activity of traditional medicinal plants from Northwestern Argentina against native pathogen and environmental microorganisms

Abstract: INTRODUCTION: Plants have been commonly used in popular medicine of most cultures for the treatment of disease. The in vitro antimicrobial activity of certain Argentine plants used in traditional medicine has been reported. The aim of this study was to investigate the antimicrobial, anti-biofilm, and anti-cell adherence activities of native plants (Larrea divaricata, Tagetes minuta, Tessaria absinthioides, Lycium chilense, and Schinus fasciculatus) collected in northwestern Argentina. METHODS: The activities of the five plant species were evaluated in Bacillus strains and clinical strains of coagulase-negative Staphylococcus isolated from northwestern Argentina and identified by 16S rDNA. RESULT: Lycium chilense and Schinus fasciculatus were the most effective antimicrobial plant extracts (15.62µg/ml and 62.50µg/ml for Staphylococcus sp. Mcr1 and Bacillus sp. Mcn4, respectively). The highest (66%) anti-biofilm activity against Bacillus sp. Mcn4 was observed with T. absinthioides and L. divaricate extracts. The highest (68%) anti-biofilm activity against Staphylococcus sp. Mcr1 was observed with L. chilense extract. T. minuta, T. absinthioides, and L. divaricata showed percentages of anti-biofilm activity of between 55% and 62%. The anti-adherence effects of T. minuta and L. chilense observed in Bacillus sp. Mcn4 reflected a difference of only 22% and 10%, respectively, between anti-adherence and biofilm inhibition. Thus, the inhibition of biofilm could be related to cell adherence. In Staphylococcus sp. Mcr1, all plant extracts produced low anti-adherence percentages. CONCLUSION: These five species may represent a source of alternative drugs derived from plant extracts, based on ethnobotanical knowledge from northwest Argentina.

Antibiotic susceptibility profile of bacilli isolated from the skin of healthy humans

Abstract In the present work, twelve bacilli were isolated from four different regions of human skin from Bela population of Nagpur district, India. The isolated bacilli were identified by their morphological, cultural and biochemical characteristics. Seven isolates were Gram negative rods, out of which five were belong to genus Pseudomonas. Three among the five Gram positive isolates were identified as Dermabactor and the remaining two Bacillus. Their antimicrobial susceptibility profile was determined by Kirby-Bauer disc diffusion method. The isolates showed resistance to several currently used broad-spectrum antibiotics. The Dermabactor genus was resistant to vancomycin, although it was earlier reported to be susceptible. Imipenem was found to be the most effective antibiotic for Pseudomonas while nalidixic acid, ampicillin and tetracycline were ineffective. Isolates of Bacillus displayed resistance to the extended spectrum antibiotics cephalosporin and ceftazidime. Imipenem, carbenicillin and ticarcillin were found to be the most effective antibiotics as all the investigated isolates were susceptible to them. Antibiotic resistance may be due to the overuse or misuse of antibiotics during the treatment, or following constant exposure to antibiotic-containing cosmetic formulations.

Effect of Biochar on the Abundance of Soil Bacteria.

A pot experiment was conducted to study the effect of biochar on the abundance of soil bacteria and compare it with the source biomass. Seven different treatments and a control were used in the experimental set-up. Three different types of biomass were selected and three types of biochar were produced from them. Both the materials were applied to the soil at a rate of 5t/ha. All treatments were incubated for 30, 60 and 90 days. Cultural, microscopic and biochemical tests were carried out to identify the bacterial isolates in soils treated with biochar and its source biomass. Bacterial isolates identified in soil and in some of the biomasses before treatments were applied include Bacillus badius, Bacillus krulwichiae, Bacillus siralis, Bacillus sylvestris, Bacillus flexus, Aneurinibacillus aneurinilyticus and Bacillus thuringiensis while after incubation periods, seven new isolates were identified. This was true for the biomass treated soils where additional one to two isolates reappeared. Conversely, in the biochar treated soils, most of the isolates disappeared except Bacillus badius that survived in all soils till 90 days. Because of its tolerant nature, it was further investigated for cellulase enzyme activity. Interestingly, the isolate did not show any such activity. Conclusively, biochar application may exert negative effect on the distribution and proliferation of soil bacteria with possible effect on soil quality and crop production.

Antioxidant, antimicrobial, toxicity and analgesic properties of ethanol extract of Solena amplexicaulis root

BACKGROUND: This study was subjected to investigate different pharmacological properties of ethanol extract ofSolena amplexicaulis root. RESULTS: The extract contains flavonoid, alkaloid, saponin and steroid compounds. The extract exhibited excellent antioxidant activity in DPPH radical scavenging activity. The extract also showed potent activity in brine shrimp lethality bioassay. The LC50 value was found to 44.677 µg/ml. The extract showed better anti-bacterial activity against gram-negative bacteria. In antifungal assay, the maximum 79.31% of anti-mycotic activity was observed against Aspergillus ochraceus while minimum 44.2% against Rhizopus oryzae. MIC value ranged between 1500 - 3000 µg/ml. The extract was found moderately toxic with a 24-hr LD50 value of 81.47 mg/kg in Swiss albino mice. The degree of inhibition by the ethanolic extract of the root was found less than that of standard analgesic drug diclofenac sodium. The extract also showed moderate anti-inflammatory and antinociceptive activity and anti-diabetic property. Reducing power of the extract was comparable with standard ascorbic acid. Moderate in vitro thrombolytic activity, lipid peroxidation inhibition property, metal chelating ability and stress-protective activity was also observed. CONCLUSION: Ethanol extract of Solena amplexicaulis root can be valuable for treatment of different diseases.

Isolation and characterization of a metal ion-dependent alkaline protease from a halotolerant Bacillus aquimaris VITP4.

A halotolerant bacterium Bacillus acquimaris VITP4 was used for the production of extracellular protease. Fractional precipitation using ammonium chloride was used to obtain the enzyme. The protease exhibited optimum activity at pH 8.0 and 40°C and retained 50% of its optimal proteolytic activity even in the presence of 4 M NaCl, suggesting that it is halotolerant. The molecular mass of protease, as revealed by SDS-PAGE was found to be 34 kDa and the homogeneity of the enzyme was confirmed by gelatin zymography and reverse-phase HPLC. Upon purification, the specific activity of th enzyme increased from 533 U/mg to 1719 U/mg. Protease inhibitors like phenyl methane sulphonyl fluoride and 2-mercaptoethanol did not affect the activity of the enzyme, but EDTA inhibited the activity, indicating the requirement of metal ions for activity. Cu­­­2+, Ni2+ and Mn2+ enhanced the enzyme activity, but Zn2+, Hg2+ and Fe2+ decreased the activity, while Mg2+, Ca2+ and K+ had no effect on the enzyme activity. The protease was quite stable in the presence of cationic (CTAB), anionic (SDS) and neutral detergents (Triton X-100 and Tween-20) and exhibited antimicrobial activity against selected bacterial and fungal strains. The stability characteristics and broad spectrum antimicrobial activity indicated the potential use of this protease in industrial applications.

Screening of antimicrobial potential of certain drug plants for enhancement of their therapeutic spectrum in vitro

Present paper deals with the in vitro screening of antimicrobial potential of Azadirachta indica and Holarrhena antidysenterica against four bacterial test species i.e. Escherichia coli, Sarcina lutea, Bacillus megaterium and Bacillus species for enhancement of their therapeutic spectrum. During this investigation, A. indica has shown more antimicrobial potential than H. antidysenterica against all bacterial species except Bacillus species. Maximum antibacterial activity was found at 100% of each drug plant extract which established a positive correlation between drug concentration and antimicrobial potential. Lowest antibacterial activity was found at 10% concentration. No activity was found against E. coli in H. antidysenterica. Investigation on drug potency at 100% concentration in terms of unit strength compared with different antibiotics, yielded that one ml of A. indica extract was equal to 5 units of Ciprofloxacin for B. megaterium and Bacillus species, and 4.2 units for E. coli. Low potency was recorded in Ampicillin than Ciprofloxacin. Drug extract of H. antidysenterica showed more unit when compared with Ciprofloxacin than Ampicillin for all bacterial test species

Isolation, partial characterization and growth characteristics of a bacterium resistant to aflatoxin B1.

A bacterium was isolated from the soil of dumping ground for cattle yard waste by enrichment culture containing aflatoxin B1. This bacterium was closely related to Bacillus firmus that was found to be a non-pathogenic bacterium. The minimum inhibitory concentration of aflatoxin B1 to the bacterium was found to be 80 microg ml(-1) as measured by total viable count and soluble protein content methods. The bacterium was sensitive to all the tested antibiotics. Plasmid curing by chemical agents did not show the resistance character residing in the plasmid. Protein profiles of cell extracts of aflatoxin B1 resistant bacterium grown in the presence and absence of the toxin showed 46 and 44 protein bands respectively in SDS-PAGE. It was observed that 39 bands were common in both the extracts and the remaining bands were showing differences near the high molecular weight range.

Influence of hexaconazole, carbofuran and ethion on soil microflora and dehydrogenase activities in soil and intact cell.

Total microbial count was highly affected (up to 61% at 1000 micrograms level) in presence of hexaconazole and persisted up to 21 days. Bacteria were more susceptible than actinomycetes. Carbofuran and ethion were moderately toxic to soil microflora. Inhibitory effects of all the three pesticides gradually decreased after 21 days as was evident by increase in total microbial count except in carbofuran. GDH activity in soil was also affected initially (up to 14 days) by all the three pesticides (60.3% in hexaconazole at 1000 micrograms level) and inhibition gradually decreased to zero except in carbofuran (15-20% toxicity persisted up to 35 days). GDH and LDH activity in presence of hexaconazole was strongly affected in intact cells of some standard culture of bacteria like Rhizobium sp. (host Dolichos sp., 32.1 and 72.5%), Bacillus subtilis Cohn (86.75 and 76.5%), Azotobacter sp. (36.9 and 55.4%) and B. sphaericus (67.6% GDH) respectively. Carbofuran inhibited the enzyme activity in B. subtilis (55.55 and 35.3%) and to some extent in B. sphaericus. Ethion moderately inhibited LDH activity in Rhodococcus sp. AK1 (17.1 and 33.3%), Rhizobium (27.6% LDH), E. coli HB 101 (34.2% LDH) as evidenced by formazan formation. From the result, it might be concluded that among the above three pesticides tested hexaconazole strongly inhibited the dehydrogenase system in bacteria including nitrogen fixing bacteria of soil and thus may affect soil fertility. It was concluded that hexaconazole was more toxic than ethion to dehydrogenase enzymes.

Degradation of 3-hydroxybenzoic acid by a Bacillus species.

A Bacillus sp. isolated by 4-hydroxybenzoate enrichment culture technique is capable of utilizing 3-hydroxybenzoate as the sole source of carbon and energy. The organism degraded 3-hydroxybenzoic acid through the intermediate formation of protocatechuic acid. 3-Hydroxybenzoate 4-hydroxylase, protocatechuate 3,4-dioxygenase and protocatechuate 4,5-dioxygenase activities were shown in cell-free extracts. The formed protocatechuate is metabolized through both the ortho and meta cleavage pathway.

Isolation and characterisation of bioactive actinomycetes from marine sediments.

Actinomycetes (28) were isolated from marine sediments off Madras coast by plating on Starch-Casein Agar medium. After preliminary studies, five isolates which were found to be promising were selected for detailed morphological, cultural, Physiological and biochemical studies. The genera encountered were Streptomycetes. Out of these five isolates, three isolates exhibited very good broad spectrum antibacterial activity. The sodium chloride tolerance of these five isolates was also tested.

Sensitivity of mosquito-pathogenic bacterial strains to various antibodies.

Four strains of Bacillus sphaericus, 1593, 2362, 9001 and 9002, B. thuringiensis H-14 and B. thuringiensis neoleonensis were tested for sensitivity against 18 antibiotics. The results revealed that all the four strains of B. sphaericus are resistant to colistin, nalidixic acid, polymyxin B and streptomycin. However, B. thuringiensis H-14 was resistant to 9 antibiotics, viz. ampicillin, cephalexin, carbenicillin, co-trimoxazole, colistin, cloxacillin, penicillin, nitrofurantoin and polymyxin B whereas B. thuringiensis neoleonensis was found to be resistant to 8 antibiotics. These results may help in isolation of potential and resistant mosquito pathogenic bacteria.

A PMA degrading constitutive organomercurial lyase in a broad-spectrum mercury resistant Bacillus pasteurii strain DR2.

A broad-spectrum Hg-resistant strain of B. pasteurii DR2 utilized phenylmercuric acetate (PMA) as sole source of carbon. This bacterial strain contained a constitutive organomercurial lyase which specifically degraded PMA but not other organo-mercurials. This PMA-lyase activity was also stimulated to different extents when this bacterial strain was grown in presence of different organic compounds as sole source of carbon.

Infección del sistema de derivación del LCR por Bacillus circulans y Bacillus larvae / Infection of the CSF shunt by Bacillus circulans and Bacillus larvae

Presentamos un ccaso de infección del sistema de derivación ventrículo atrial por B. circulans y B. larvae en dos episodios diferentes. En el primero se aisló B. circulans en 4 de 6 hemocultivos y en el líquido cefalorraquídeo obtenido de la válvula de derivación. La cepa aislada, que determinó un síndrome de daño cerebral, fue productora de un factor tóxico, letal para el ratón y por sus propiedades bioquímicas considerada como cepa variante ya que la producción de ureasa y su crecimiento en ClNa al 7% no coincide con lo descripto en el Manual de Bergey. La enferma curó sin secuelas, con tratamiento antibiótico con: cefotaxime, cotrimoxazol y rifampicina. La segunda infección ocurrió a los dos meses de suspendido el tratamiento antibiótico y se aisló B. larvae de líquido cefalorraquídeo y de la válvula de derivación. Por microscopía electrónica se observaron leucocitos y bacilos adheridos a las anfractuosidades del plástico. Según nuestra información se trata del primer caso de infección por B. larvae en humanos