scholarly journals Vulnerability of Pathogenic Biofilms to Micavibrio aeruginosavorus

2006 ◽  
Vol 73 (2) ◽  
pp. 605-614 ◽  
Author(s):  
Daniel Kadouri ◽  
Nel C. Venzon ◽  
George A. O'Toole

ABSTRACT The host specificity of the gram-negative exoparasitic predatory bacterium Micavibrio aeruginosavorus was examined. M. aeruginosavorus preyed on Pseudomonas aeruginosa, as previously reported, as well as Burkholderia cepacia, Klebsiella pneumoniae, and numerous clinical isolates of these species. In a static assay, a reduction in biofilm biomass was observed as early as 3 hours after exposure to M. aeruginosavorus, and an ∼100-fold reduction in biofilm cell viability was detected following a 24-h exposure to the predator. We observed that an initial titer of Micavibrio as low as 10 PFU/well or a time of exposure to the predator as short as 30 min was sufficient to reduce a P. aeruginosa biofilm. The ability of Micavibrio to reduce an existing biofilm was confirmed by scanning electron microscopy. In static and flow cell experiments, M. aeruginosavorus was able to modify the overall P. aeruginosa biofilm structure and markedly decreased the viability of P. aeruginosa. The altered biofilm structure was likely caused by an increase in cell-cell interactions brought about by the presence of the predator or active predation. We also conducted a screen to identify genes important for P. aeruginosa-Micavibrio interaction, but no candidates were isolated among the ∼10,000 mutants tested.

2019 ◽  
Vol 75 (4) ◽  
pp. 925-935 ◽  
Author(s):  
Farhana Alam ◽  
Dominic Catlow ◽  
Alessandro Di Maio ◽  
Jessica M A Blair ◽  
Rebecca A Hall

Abstract Background Pseudomonas aeruginosa is an opportunistic bacterium that infects the airways of cystic fibrosis patients, surfaces of surgical and burn wounds, and indwelling medical devices. Patients are prone to secondary fungal infections, with Candida albicans being commonly co-isolated with P. aeruginosa. Both P. aeruginosa and C. albicans are able to form extensive biofilms on the surfaces of mucosa and medical devices. Objectives To determine whether the presence of C. albicans enhances antibiotic tolerance of P. aeruginosa in a dual-species biofilm. Methods Single- and dual-species biofilms were established in microtitre plates and the survival of each species was measured following treatment with clinically relevant antibiotics. Scanning electron microscopy and confocal microscopy were used to visualize biofilm structure. Results C. albicans enhances P. aeruginosa biofilm tolerance to meropenem at the clinically relevant concentration of 5 mg/L. This effect is specific to biofilm cultures and is dependent upon C. albicans extracellular matrix polysaccharides, mannan and glucan, with C. albicans cells deficient in glycosylation structures not enhancing P. aeruginosa tolerance to meropenem. Conclusions We propose that fungal mannan and glucan secreted into the extracellular matrix of P. aeruginosa/C. albicans dual-species biofilms play a central role in enhancing P. aeruginosa tolerance to meropenem, which has direct implications for the treatment of coinfected patients.


2014 ◽  
Vol 32 (2) ◽  
pp. 129 ◽  
Author(s):  
Umi Hidayati ◽  
Iswandi Anas Chaniago ◽  
Abdul Munif ◽  
Siswanto Siswanto ◽  
Dwi Andreas Santosa

Bakteri endofit adalah bakteri yang hidup dalam jaringan tanaman, dapat diisolasi melalui sterilisasi permukaan jaringan tanaman. Isolasi bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan sangat penting dilakukan. Pembuatan kultur campuran dari bakteri endofit diharapkan meningkatkan potensi dalam memacu pertumbuhan yang dapat meningkatkan kualitas bibit batang bawah tanaman karet. Penelitian ini dilakukan dengan tujuan mendapatkan kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Lima bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan yaitu Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, Brachybacterium paraconglomeratum LPD74, bacterium (bakteri tidak dikenal) LPD76, dan Providencia vermicola KPA38, diuji kompatibilitas untuk mendapatkan kultur campuran yang dapat meningkatkan pertumbuhan bibit batang bawah PB 260. Semua bakteri endofit terpilih kompatibel satu dengan yang lain. Aplikasi kultur campuran untuk meningkatkan pertumbuhan bibit batang bawah PB 260 memberikan hasil 2 kultur campuran terbaik. Kultur campuran 1 terdiri 2 spesies bakteri yaitu Brachybacterium paraconglomeratum LPD74 dan Providencia vermicola KPA38.  Kultur campuran 2 terdiri 3 spesies bakteri yaitu  Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, dan Brachybacterium paraconglomeratum LPD74. Bakteri endofit mampu masuk ke planlet bibit karet microcutting yang dibuktikan dengan Scanning Electron Microscopy. Diterima : 19 Mei 2014; Direvisi : 30 Mei 2014; Disetujui : 21 Juni 2014  How to Cite : Hidayati, U., Chaniago, I. A., Munif, A., Siswanto., & Santosa, D. A. (2014). Potensi kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Jurnal Penelitian Karet, 32(2), 129-138. Retrieved from http://ejournal.puslitkaret.co.id/index.php/jpk/article/view/159


2002 ◽  
Vol 46 (1-2) ◽  
pp. 253-256
Author(s):  
F. Tessele ◽  
G. Englert ◽  
L.O. Monteggia

Biofilm development onto polypropylene particles (<4 mm) was studied in a laboratory-scale down flow anaerobic fluidised bed reactor. The reactor was fed with a synthetic solution containing sucrose and nutrients, and operated at 35°C during 65 days at 44% bed expansion rate and 36 h HRT. Scanning electron microscopy (SEM) monitored the biofilm development. Initial adhesion occurred within the first 6 hours and after day 44 biofilm structure was complete. The presence of attached cells morphologically similar to Methanotrix bacilli and Methanosarcina sp. was observed by Scanning Electron Microscopy (SEM). The biofilm and the carrier surface roughness were measured by atomic force microscopy (AFM) and yielded 9.1 and 75 nm respectively. Results also showed good correlation between the SEM characterisation and the conventional anaerobic reactor parameters.


2017 ◽  
Vol 41 (1) ◽  
pp. 60-65
Author(s):  
Ahmad N. A. Salih ◽  
Mohammad J. Eesa

     This study was conducted for the synthesis of silver nanoparticles by using olive leaves aqueous extract and evaluate its antibacterial activity against Pseudomonas aeruginosa in vitro. The synthesis and characterization of silver nanoparticles was confirmed by Ultra Violet Visible – spectrophotometer and Scanning Electron Microscopy. Well diffusion method was used to show the antibacterial action of silver nanoparticles against Pseudomonas aeruginosa in vitro in comparison with standard antibacterial silver sulfadiazine by using different concentrations of each agent ranged from 12.5-200 μg/ml. The results of this study showed it possible to produce silver nanoparticles in eco-friendly and easy process and UV-Visible absorption spectra of the silver nanoparticles revealed maximum absorbance at 420 and 430 nm. The Scanning Electron Microscopy analysis demonstrated the mean of the silver particles diameter was 26 nm. The antibacterial findings of the synthesized silver nanoparticles against Pseudomonas aeruginosa in vitro showed that the silver nanoparticles were more effective than silver sulfadiazine against Pseudomonas aeruginosa. It could be concluded that olive leaves extract can be used effectively in the production of silver nanoparticles and these synthesized nanoparticles had considerable antibacterial activity against Pseudomonas aeruginosa in vitro.                                                        


2016 ◽  
Vol 82 (2) ◽  
Author(s):  
Irma KRESNAWATY ◽  
Agustin Sri MULYATNI ◽  
Deden Dewantara ERIS ◽  
Haryo Tejo PRAKOSO

AbstractThe difficulties in processing of petroleum-based plastic waste had encouraged the development of biodegradable plastics polyhydroxyalkanoate (PHA). Researchers isolated the PHA-producing microorganisms from various sources to obtain new species with high PHA production capability. In addition, the high cost of PHA production might be overcome by using carbon-rich waste, such as palm oil mill effluent (POME). This research conducted characterization of produced PHA and optimization of PHA production in POME. In previous research, three potential isolates were obtained, which are one Pseudomonas aeruginosa isolate and two Bacillus subtilis isolates. Analysis of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) showed the presence of PHA accumu-lation within the bacterial cell. The results of Spectra of Fourier Transform Infra Red Spectroscopy (FT-IR) revealed differences in C-C and C-H alipathic regions of PHA produced by Pseudomonas aeruginosa and Bacillus subtilis. Optimum production of PHA was obtained using POME at concentration of 50-25% during 6 days of incubation time in an enriched media pretreatment.Abstrak Sulitnya pengolahan limbah plastik berbasis minyak bumi mendorong pengembangan plastik biodegradable poli-hidroksialkanoat (PHA). Beberapa peneliti mengisolasi mikroorganisme penghasil  PHA dari berbagai sumber karena diharapkan akan diperoleh spesies baru dengan kemampuan produksi PHA yang tinggi. Selain itu kendala tingginya biaya produksi PHA dapat diatasi dengan peman-faatan limbah yang kaya akan  karbon, seperti limbah cair pabrik kelapa sawit (LCPKS). Pada penelitian ini dilakukan karakterisasi PHA yang dihasilkan dan optimasi produksi PHA pada LCPKS. Pada penelitian sebelumnya telah diperoleh  tiga isolat potensial, yaitu : satu isolat  Pseudo-monas aeruginosa dan dua isolat  Bacillus subtilis.  Analisis Scanning Electron Microscopy (SEM) dan Transmission Electon Microscopy (TEM) menunjukkan adanya akumulasi PHA di dalam sel bakteri. Dari hasil analisis FT-IR disimpulkan bahwa senyawa PHA yang dihasilkan Pseudo-monas aeruginosa  berbeda dengan  Bacillus subtilisyang ditandai   perbedaan   pada  spectra   gugus  C-C  dan   C-H alifatik.  Produksi optimum PHA diperoleh pada konsentrasi LCPKS 50-25%, waktu inkubasi  enam hari dan optima-lisasi pertumbuhan pada media kaya di awal untuk mening-katkan populasi mikroba.


2011 ◽  
Vol 291-294 ◽  
pp. 614-620 ◽  
Author(s):  
Yun Liu ◽  
Yu Ling Guo ◽  
Da Wei Chen ◽  
Cheng Peng ◽  
Yun Jun Yan

Cross-linked enzyme aggregates (CLEAs) of lipase from Burkholderia cepacia (BCL) were explored using different precipitants and different amount of glutaraldehyde as cross-linkers. The ‘fresh’ and ‘mature’ CLEAs-BCL was successfully encapsulated with sol-gel support. The latter showed the highest specific enzyme activity, which was 1.7 and 13.2-fold over CLEAs-BCL before encapsulation with sol-gel and free BCL, respectively. It performed high transesterification activity with the biodiesel yield of 88.5%. The ‘mature’ CLEAs-BCL presented high stability in the ranges of temperature (30-70 ºС) and pH (pH = 5-10). Scanning electron microscopy (SEM) and circular dichroism (CD) studies showed that the morph secondary structure of ‘fresh’ and ‘mature’ CLEAs-BCL was variant to some extent, which may be responsible for the catalytic activity variance.


2014 ◽  
pp. 129-138
Author(s):  
Umi Hidayati ◽  
Iswandi Anas Chaniago ◽  
Abdul Munif ◽  
Siswanto Siswanto ◽  
Dwi Andreas Santosa

Bakteri endofit adalah bakteri yang hidup dalam jaringan tanaman, dapat diisolasi melalui sterilisasi permukaan jaringan tanaman. Isolasi bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan sangat penting dilakukan. Pembuatan kultur campuran dari bakteri endofit diharapkan meningkatkan potensi dalam memacu pertumbuhan yang dapat meningkatkan kualitas bibit batang bawah tanaman karet. Penelitian ini dilakukan dengan tujuan mendapatkan kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Lima bakteri endofit dari tanaman karet yang berpotensi sebagai pemacu pertumbuhan yaitu Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, Brachybacterium paraconglomeratum LPD74, bacterium (bakteri tidak dikenal) LPD76, dan Providencia vermicola KPA38, diuji kompatibilitas untuk mendapatkan kultur campuran yang dapat meningkatkan pertumbuhan bibit batang bawah PB 260. Semua bakteri endofit terpilih kompatibel satu dengan yang lain. Aplikasi kultur campuran untuk meningkatkan pertumbuhan bibit batang bawah PB 260 memberikan hasil 2 kultur campuran terbaik. Kultur campuran 1 terdiri 2 spesies bakteri yaitu Brachybacterium paraconglomeratum LPD74 dan Providencia vermicola KPA38.  Kultur campuran 2 terdiri 3 spesies bakteri yaitu  Bacillus cereus KPD6, Pseudomonas aeruginosa KPA32, dan Brachybacterium paraconglomeratum LPD74. Bakteri endofit mampu masuk ke planlet bibit karet microcutting yang dibuktikan dengan Scanning Electron Microscopy. Diterima : 19 Mei 2014; Direvisi : 30 Mei 2014; Disetujui : 21 Juni 2014  How to Cite : Hidayati, U., Chaniago, I. A., Munif, A., Siswanto., & Santosa, D. A. (2014). Potensi kultur campuran bakteri endofit sebagai pemacu pertumbuhan bibit tanaman karet. Jurnal Penelitian Karet, 32(2), 129-138. Retrieved from http://ejournal.puslitkaret.co.id/index.php/jpk/article/view/159


2016 ◽  
Vol 82 (2) ◽  
Author(s):  
Irma KRESNAWATY ◽  
Agustin Sri MULYATNI ◽  
Deden Dewantara ERIS ◽  
Haryo Tejo PRAKOSO

AbstractThe difficulties in processing of petroleum-based plastic waste had encouraged the development of biodegradable plastics polyhydroxyalkanoate (PHA). Researchers isolated the PHA-producing microorganisms from various sources to obtain new species with high PHA production capability. In addition, the high cost of PHA production might be overcome by using carbon-rich waste, such as palm oil mill effluent (POME). This research conducted characterization of produced PHA and optimization of PHA production in POME. In previous research, three potential isolates were obtained, which are one Pseudomonas aeruginosa isolate and two Bacillus subtilis isolates. Analysis of Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) showed the presence of PHA accumu-lation within the bacterial cell. The results of Spectra of Fourier Transform Infra Red Spectroscopy (FT-IR) revealed differences in C-C and C-H alipathic regions of PHA produced by Pseudomonas aeruginosa and Bacillus subtilis. Optimum production of PHA was obtained using POME at concentration of 50-25% during 6 days of incubation time in an enriched media pretreatment.Abstrak Sulitnya pengolahan limbah plastik berbasis minyak bumi mendorong pengembangan plastik biodegradable poli-hidroksialkanoat (PHA). Beberapa peneliti mengisolasi mikroorganisme penghasil  PHA dari berbagai sumber karena diharapkan akan diperoleh spesies baru dengan kemampuan produksi PHA yang tinggi. Selain itu kendala tingginya biaya produksi PHA dapat diatasi dengan peman-faatan limbah yang kaya akan  karbon, seperti limbah cair pabrik kelapa sawit (LCPKS). Pada penelitian ini dilakukan karakterisasi PHA yang dihasilkan dan optimasi produksi PHA pada LCPKS. Pada penelitian sebelumnya telah diperoleh  tiga isolat potensial, yaitu : satu isolat  Pseudo-monas aeruginosa dan dua isolat  Bacillus subtilis.  Analisis Scanning Electron Microscopy (SEM) dan Transmission Electon Microscopy (TEM) menunjukkan adanya akumulasi PHA di dalam sel bakteri. Dari hasil analisis FT-IR disimpulkan bahwa senyawa PHA yang dihasilkan Pseudo-monas aeruginosa  berbeda dengan  Bacillus subtilisyang ditandai   perbedaan   pada  spectra   gugus  C-C  dan   C-H alifatik.  Produksi optimum PHA diperoleh pada konsentrasi LCPKS 50-25%, waktu inkubasi  enam hari dan optima-lisasi pertumbuhan pada media kaya di awal untuk mening-katkan populasi mikroba.


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