MOSP - Macao Scientific Publishers

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Investigation of in vitro effects of daptomycin, tigecycline and teicoplanin combinations against MRSA, VISA and VRE strains

Ahmet Yilmaz Coban*, Aydin Deveci, Ozlem Acicbe, Nuriye Tasdelen Fisgin, Alper Ciftci, Basak Dokuzoguz and Belma Durupinar

Abstract: Multidrug resistant (MDR) gram positive infectious agents can cause severe infections and monotherapy of these infections by current available antimicrobial agents can be problematic. Therefore, antimicrobial combination therapy may be needed for effective treatment. The study aimed to investigate in vitro effects of binary combinations of tigecycline (TGC), daptomycin (DPC) and teicoplanin (TP) against 4 methicillin resistant Staphylococcus aureus (MRSA), 2 vancomycin intermediate S. aureus (VISA) and 9 vancomycin resistant enterococci (VRE) species by E test method. Whilst, all binary combination of TGC, DPC and TP showed synergistic effect against standard strain of S. aureus and 50% of clinical MRSA isolates, all of the combinations except DPC-TP combination showed additive effect against VISA strains (Mu 3 and Mu 50). TGC-TP, DPC-TP and TGC-DPC combinations showed additive effect against 25, 60 and 50% of clinical VRE isolates, respectively. Synergistic effect was observed in combinations of TGC-TP and DPC-TGC against 2 and 1 VRE clinical isolates, respectively. Combinations of TP with any of TGC and DPC brought MIC values of TP below the level of sensitivity in all of TP resistant VRE and VISA isolates. Antagonistic effect was not observed in combinations of tested drugs against any strains. In conclusion, in vitro effectiveness of these drug combinations may reflect advantages in clinical practice for severe MDR gram positive bacterial infections.[...] Read More.

Keywords: Multidrug resistant, antimicrobial agents, methicillin resistant Staphylococcus aureus, infectious agents, vancomycin resistant enterococci.

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A binding of ECM proteins - collagen, fibronectin, albumin and vitronectin by Bacteriocinogennic enterococci isolated from chicken and rabbits

Igor Štyriak*, Viola Strompfová, Iveta Štyriaková, Monika Simonová and Andrea Lauková

Abstract: Ten Bacteriocinogennic enterococci, isolates from chicken and rabbits, were examined for their binding of collagen, fibronectin, albumin and vitronectin in tubes with Nutrient broth No.2. For ECM binding examination, enterococci were grown in MRS broth under normal air conditions at 37°C. Individual strains expressed binding of selected glycoproteins to various degrees, however, vitronectin was bound the best from these four ECM proteins. These observations lead to suggestion that at least one mode of enterococcal attachment utilizes glycosaminoglycan chains present on the surface of adherent cells. Significance and impact of the study is that some animal strains are comparable with the commercially used strains with respect to their ECM ability. As this feature is important for probiotic bacteria to be able to colonize intestine, these strains could be considered for their wider use in fermented feed for animals.[...] Read More.

Keywords: Enterococcus, extracellular matrix, collagen, fibronectin, albumin and vitronectin.

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Determination of the ability of microorganisms isolated from mechanic soil to utilise lubricating oil as carbon source

A. Sebiomo*, S. A. Bankole and A. O. Awosanya

Abstract: Ten bacteria and five fungi capable of utilising lubricating oil as carbon source were isolated from mechanic soil. The growth profiles were determined by monitoring the optical density, total viable counts, dry weights and pH of the culture utilizing lubricating oil as sole carbon and energy source. The total viable counts increased significantly with optical density and dry weights of fungi as the days of incubation progressed until the 14th day (P < 0.001). There was significant decrease in pH (P < 0.001) as fungal cells metabolised lubricating oil, Pseudomonas aeruginosa produced the highest optical density and viable count values of 0.441 and 8.31 to the end of 14th day of incubation among all bacterial isolates used in this study. P. aeruginosa also presented lowest pH value of 6.53 after 14 days of incubation between all bacterial isolates. Bacillus licheniformis and Enterobacter aerogenes recorded the lowest optical density and viable count values of 0.19 and 8.1 of all bacterial isolates after 14th day of incubation, Enterobacter aerogenes had the highest pH value of 6.8. Of all the fungal isolates used in this study Aspergillus niger and Aspergillus terreus recorded the highest dry weight and viable count values of 19.3 and 6.41. Trichoderma sp. had the lowest pH, dry weight and viable count values of 5.1, 17 and 6.3, respectively, Aspergillus flavus had the highest pH of 5.6. Correlation analysis indicated negative correlation between optical density and pH (correlation coefficient = +0.174) and between viable counts and pH (correlation coefficient = +0.159), there was positive correlation between viable counts and optical density (correlation coefficient = 0.735). For the fungal isolates there was negative correlation between dry weights and pH (correlation coefficient = +0.958) and between viable counts and pH (correlation coefficient = -0.830). The correlation analysis between fungal dry weights and viable counts showed positive correlation (0.786). The utilization of hydrocarbon in lubricating oil resulted in gradual reduction in the oil layer and complete disappearance of the oil with prolonged incubation. This study has shown that the microorganisms isolated from mechanic soils have potential application in the bioremediation of sites polluted with lubricating oil.[...] Read More.

Keywords: Bacteria, fungi, lubricating oil, biodegradation.

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Isolating endophytic fungi from evergreen plants and determining their antifungal activities

Changhong Liu*, Tingting Liu, Fengfeng Yuan and Yucheng Gu

Abstract: A total of 262 strains of endophytic fungi were isolated from 23 evergreen plant species collected from Zijin Mountain in Nanjing, China. Two-hundred and three of the fungi isolates were classified into 23 taxa in 19 genera based on colony morphology and microscopic observation of mycelia and asexual/sexual spores. The highest richness was obtained from Cedrus deodara (28), while the highest diversity of identified species (6) was isolated from Sabina procumbens. Some fungi appeared to be host-specific, such as Botrytis ricini lt300, Geotrichum candidum lt274 and Lacellina graminicola lt256, while other strains (e.g. Alternaria alternata lt222, Anthina sp. Lt147, Colletotrichum gloeosporioids lt305 and Fusarium solani lt293) were commonly isolated from a range of plants. The richness of the endophytic fungi recovered from plant branches was significantly higher than those from leaves. Moreover, about 70% of the obtained endophytic fungi could produce antifungal metabolites against at least one plant pathogenic fungi. The EtOAc extracts of seven species of Anthina sp. lt147, C. gloeosporioids lt305, Ectostroma sp. Lt144, Fusarium decemcellulare lt183, Fusarium oxysporum lt173, Paraconiothyrium brasiliense lt161 and C. montemartinii lt198 showed broad inhibition against the growth of all the six phytopathogens with the inhibition rates from 20 to 80%. These results indicated that endophytic fungi may play an important role in protection of the evergreen plants from disease as well as an excellent resource for searching for natural antifungal compounds.[...] Read More.

Keywords: Endophytic fungi, evergreen plants, antifungal activity.

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Microbial morphology and community structure in a suspended carrier biofilm reactor as a function of substrate loading rates

Fu Bo, Liao Xiaoyi, Ding Lili, Xu Ke and Ren Hongqiang*

Abstract: An aerobic suspended carrier biofilm reactor was efficient in simultaneous organic carbon and nitrogen removal, with COD removal efficiencies of 87.1–99.0% and simultaneous nitrification and denitrification (SND) efficiencies about 96.7-98.8%. The effects of substrate loading on microbial morphology and community structure were investigated by environmental scanning electron microscopy (ESEM), denaturing gel gradient electrophoresis (DGGE) and fluorescence in situ hybridization (FISH). Biofilms formed at different substrate loadings had different morphology and community structures. A higher substrate concentration resulted in denser and thinner biofilms, while a lower substrate concentration resulted in looser and thicker biofilms with significant presence of filamentous bacteria. Both sequence analysis of DGGE bands and FISH analysis indicated the dominance of β-Proteobacteria in the biofilm communities, especially Zoogloea. FISH analysis revealed that the relative abundance of β-proteobacteria ammonia oxidizing bacteria (AOB) was positively correlated with ammonium concentrations, whereas Nitrospira-like nitrite-oxidizing bacteria (NOB) were negatively affected by ammonia and nitrite concentrations. The presence of denitrifying bacteria, Hydrogenophaga spp., Hyphomicrobium spp. and Rhizobium spp. suggested that not only the oxygen microgradients within the biofilm but also aerobic denitrifiers may be responsible for SND in the aerobic biofilm.[...] Read More.

Keywords: Microbial community structure, microbial morphology, substrate loading, suspended carrier biofilm.

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Bacteriological quality of some Nigerian currencies in circulation

S. Awe*, K. I .T. Eniola, F. T. Ojo and A. Sani

Abstract: The bacteriological quality of some Nigerian currencies in circulation was investigated in terms of total bacterial count and kinds of bacterial species present. The notes had high bacterial counts: ranging from 1.5×104 to 4.2×104 cfu/cm2; there was no significant difference in the bacterial counts. Eight bacterial species were isolated: Escherichia coli, Staphylococcus aureus, Proteus mirabilis, Streptococcus faecalis, Klebsiella sp., Pseudomonas aeroginosa, Bacillus subtilis and Salmonella sp. Salmonella sp. was the least prevalent of the bacterial isolates (2%) while S. aureus was the most prevalent (28%). Antibiotic susceptibility pattern suggests that some of the isolates (S. aureus and P. mirabilis) had potentials for multiple antibiotic resistances. The health implications of the organisms encountered are discussed and suggestions are provided to enable safe handling of the notes.[...] Read More.

Keywords: Currencies, naira notes, antibiotic resistance.

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Studies on the culturable marine actinomycetes isolated from the Nahoon beach in the Eastern Cape Province of South Africa

Isoken H. Ogunmwonyi, Ntsikelelo Mazomba, Leonard Mabinya, Elvis Ngwenya, Ezekiel Green, David A. Akinpelu, Ademola O. Olaniran, Kim Bernard and Anthony I. Okoh*

Abstract: A total of 84 culturable marine actinomycetes belonging to 15 generic morphotypes were isolated from water and rock scrapings from the Nahoon beach, a coastal shore of Indian Ocean in the Eastern Cape Province of South Africa. The colonies showed diverse morphological characteristics and their occurrence and distribution varied with sample type. The rock scrappings yielded more actinomycetes morphotypes than the water samples. Streptomyces was most prevalent in both samples. Actinoplane, Actinosynnema, Norcadia, Norcardiopsis, Streptosporagium and Intrasporagium were present in rock scrapings but absent in water samples. Kibdellosporium was present in water sample and absent in rock scrapings. The Streptomyces isolates were selected and preliminarily screened for antimicrobial activity. The bioactive compounds of 10 most potent Streptomyces isolate was extracted twice with equal volume of ethyl acetate (1:1 v/v). The ethyl acetate extracts of the putative Streptomyces isolates showed activities against at least 6 and up to 26 of the 32 test bacteria screened. Inhibition zones were found to range between 9 and 32 mm diameters at a concentration of 10 mg/ml. The partial characterization of the crude extracts by IR spectra analysis revealed the possible presence of terpenoid, long chain fatty acids and secondary amine derivatives compounds in the extracts. We conclude that the Nahoon beach promises to be a veritable resource for diverse marine actinomycetes of potentials for bioactive compounds production and novel drug discovery.[...] Read More.

Keywords: Morphotypes, occurrence, rock scrapings, IR spectral, bioactive compound.

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Molecular detection of invA and spv virulence genes in Salmonella enteritidis isolated from human and animals in Iran

Kumarss Amini, Taghi Zahraei Salehi*, Gholamreza Nikbakht, Reza Ranjbar, Javid Amini and Shahrnaz Banou Ashrafganjooei

Abstract: It is important to study the genotypic diversity of Salmonella plasmid genes which are responsible for its virulence. In the present study multiplex polymerase chain reaction (multiplex PCR) assay was carried out for detection of Salmonella enteritidis and presence of invA and spv genes. In the first stage of the study, 1001 poultry samples were collected from a slaughterhouse in Kerman province (southern Iran). Biochemical and serological tests were then performed for identification of Salmonella serovars and 6.79% (68/1001) were positive for Salmonella. Multiplex PCR with three set primers was then applied to confirm serovar enteritidis 51.4% (35/68). Simple-PCR was then applied to detect spvA (Salmonella plasmid virulence), and spvB genes. Finally, multiplex PCR assay was carried out to simultaneously detect and identify invA and spvC genes. The presence of spvA, spvB and spvC in S. enteritidis was 88.6% for each gene. In the second stage of the study, thirty-three bovine (n = 13) and human (n = 20) S. enteritidis strains were isolated from the culture collection in the Department of Microbiology, Faculty of Veterinary Medicine, University of Tehran, Iran. The analyses of the samples revealed that spvA, spvB, and spvC genes were present in 90% of S. enteritidis from human sources as compared to 100% in bovine sources. The study represents the first report in Iran about the genotypic diversity of spvA, spvB and spvC genes of S. enteritidis.[...] Read More.

Keywords: Salmonella enteritidis, multiplex PCR, virulence genes.

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Growth inhibition (in vitro) of Colletotrichum gloeosporioides isolated from cassava (Manihot esculenta) using Trichoderma longibrachiatum

A. A. Sobowale*, O. A. Odeyingbo, H. O. Egberongbe, R. T. Feyisola, O. A. Ayinde and A. Adesemowo

Abstract: The growth inhibition of Colletotrichum gloeosporioides isolated from cassava was studied in-vitro using Trichoderma longibrachiatum. Both fungi were cultured together on the same Petri plate using three different pairing methods. Inoculation of each fungus on separate Petri plates served as controls. For each pairing method, experiments were conducted in five replicates. Radial growth (cm) of both C. gloeosporioides and T. longibrachiatum in all Petri plates were measured daily for 7 days. In all the three pairing methods, T. longibrachiatum significantly inhibited the growth of C. gloeosporioides (P > 0.0001). Growth inhibition of C. gloeosporioides by T. longibrachiatum was better in ‘inoculating antagonist before pathogen’ than in the other two pairing methods (P = 0.05). C. gloeosporioides had significant addition of radial mycelia only between days 1 and 2, as well as days 2 and 3 after pairing (DAP) before contact was made with T. longibrachiatum. Addition of mycelia mass of C. gloeosporioides slowed down significantly by the day upon contact with T. longibrachiatum (P = 0.05, R2 = 0.86). F value for day after pairing (DAP) was also highly significant (P > 0.0001). T. longibrachiatum could thus be said to possess probable antagonistic tendency against C. gloeosporioides.[...] Read More.

Keywords: Colletotrichum gloeosporioides, Trichoderma longibrachiatum, Manihot esculenta, day after pairing, growth inhibition.

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Identification and characterization of tenuazonic acid as the causative agent of Alternaria alternata toxicity towards groundnut

P. Suvarnalatha Devi, M. N. Reddy, M. Nagalakshmi Devamma, P. Jayalakshmi, G. Revathi and G. Narasimha*

Abstract: Alternaria alternata (Fr.) Keissler, the causal agent of Alternariosis of groundnut seeds ( Arachis hypogaea L.) was toxigenic when cultured on various laboratory media. The cell free extract or culture filtrate induced severe chlorosis and necrosis on leaves, inhibition of root and shoot growth of germinating seeds and wilting of seedlings. A phytotoxin was isolated both from cell free extract/culture filtrate and infected tissues, purified and identified as tenuazonic acid, by using thin layer chromatography, ultra violet and infra red spectral analysis. Toxicity was monitored with standard bioassay techniques. The results show patho-physiological significance of tenuazonic acid in disease syndrome.[...] Read More.

Keywords: Alternaria alternata, groundnut, alternariosis, tenuazonic acid.

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