Microbion Biosciences

In Vitro Efficacy of Bismuth Thiols Against Biofilms Formed by Bacteria Isolated from Human Chronic Wounds

admin — Fri, 12 Aug 2011 15:04:04 +0000

Journal of Applied Microbiology (August 2011)

Abstract

Aims: The purpose of this study was to evaluate the antimicrobial efficacy of thirteen bismuth thiol preparations for bactericidal activity against established biofilms formed by two bacteria isolated from human chronic wounds.

Methods: Single species biofilms of a Pseudomonas aeruginosa or a methicillin resistant Staphylococcus aureus were grown in either colony biofilm or drip-flow reactors systems. Biofilms were challenged with bismuth thiols, antibiotics or silver sulfadiazine, and log reductions were determined by plating for colony formation.

Conclusions: Antibiotics were ineffective or inconsistent against biofilms of both bacterial species tested. None of the antibiotics tested were able to achieve >2 log reductions in both biofilm models. The 13 different bismuth thiols tested in this investigation achieved widely varying degrees of killing, even against the same micro-organism in the same biofilm model. For each micro-organism, the best bismuth thiol easily outperformed the best conventional antibiotic.

Against P. aeruginosa biofilms, bismuth-2,3-dimercaptopropanol (BisBAL) at 40–80 lg ml)1 achieved >7.7 mean log reduction for the two biofilm models. Against MRSA biofilms, bismuth-1,3-propanedithiol ⁄ bismuth-2-mercaptopyridine N-oxide (BisBDT ⁄ PYR) achieved a 4.9 log reduction.

Significance and Impact of the Study: Bismuth thiols are effective antimicrobial agents against biofilms formed by wound bacteria and merit further development as topical antiseptics for the suppression of biofilms in chronic wounds.

Initiation of Phase 1 Clinical Trial for Topical treatment of Acute Skin and Skin Structure Infections

admin — Fri, 29 Jul 2011 14:26:36 +0000

Microbion Corporation, a Montana-based pharmaceutical company focused on development of novel
therapeutics for treatment of bacterial infections, announced today that it has initiated a Phase 1 clinical
trial of the company’s lead topical anti-infective drug product. The double-blind randomized, placebo
controlled study is being conducted at clinical sites in the United Kingdom and will assess safety,
tolerability, and pharmacokinetics…

Download Full Press Release – Microbion Corporation Press Release (07.05.11)

Bismuth Dimercaptopropanol (BisBAL) Inhibits Formation of Multispecies Wastewater Flocs

admin — Sat, 12 Mar 2011 15:09:21 +0000

Journal of Applied Microbiology (2011)

Abstract

Aims: To determine the ability of a bismuth thiol to control floc formation in a multispecies population of micro-organisms obtained from the activated sludge unit of a wastewater treatment plant. The molecular level mechanisms by which bismuth-2-3-dimercapto-1-propanol (BisBAL) inhibits bioaggregation are also elucidated.

Methods and Results: Micro-organisms were grown over a 3-day period in a batch system by adding glucose as an electron donor to stimulate short-term heterotrophic activity. Extracellular polymeric substances (EPS) produced by activated sludge micro-organisms during exponential and stationary growth phases in the presence and absence of BisBAL were characterized using colorimetry, X-ray photoelectron spectroscopy (XPS), and Fourier transform infrared (FTIR) spectroscopy. BisBAL at its minimum inhibitory concentration (MIC, 10 lmol l)1) was most effective in suppressing microbial floc formation. The principal effect of sub-inhibitory concentrations of BisBAL was to decrease total EPS production while largely preserving homology.

Conclusions: Antifouling and bactericidal properties of BisBAL arise from its ability to reduce EPS expression and preferentially suppressing acidic and O-acetylated carbohydrates and certain protein secondary structures viz. b-structures, random coils, and a-and 3-turn helices. As micro-organisms exhibited a much weaker tendency to aggregate at lower concentrations of these specific EPS components, they also appear to be important for the formation of microbial flocs and bioaggregates.

Significance and Impact of the Study: BisBAL was shown to be highly effective against multispecies microbial aggregation. Novel bismuth-based biocides could also be potentially employed to control excess sludge production in wastewater treatment systems by inhibiting EPS expression.

Microbion BioSciences Corporation Part of New Institute Committed to Improved Treatment of War Wounded

admin — Mon, 05 Apr 2010 18:02:52 +0000

Bozeman, Montana – The United States Army Medical Research and Materiel Command (USAMRMC), in conjunction with the Office of Naval Research (ONR), the National Institutes of Health (NIH), the Office of the Air Force of the Surgeon General (AF/SG), and the Department of Veterans Affairs, have awarded $85 million to two consortia which in combination with the US Army Institute of Surgical Research (USAISR), form the Armed Forces Institute of Regenerative Medicine (AFIRM). Overall funding to the consortia from all sources is expected to exceed $250 million over the next five years.

The use of improvised explosive devices (IEDs) in Iraq and Afghanistan has caused a marked increase in severe blast trauma, now responsible for approximately 75% of all injuries, according to the Journal of Orthopaedic Trauma. Many of those who survive such explosive trauma are challenged with healing from severe limb, head, face, and burn injuries that can take years to treat and usually result in significant lifelong impairment. The AFIRM awards represent a national effort to address the health care challenges of these severely injured military personnel.

Microbion Corporation (Microbion) of Bozeman, Montana, is proud to be a corporate partner in one of the two awarded consortia: the Alliance for Regenerative Medicine – RCC AFIRM. Microbion is the sole Montana firm represented in this consortium. The mission of this consortium is to accelerate advances in regenerative medicine, and to translate these advances as quickly as possible into practical, therapeutic tools applied both in military combat and hospital environments. These new therapies will focus on the treatment of burns, regeneration of bone, muscle, tendon, nerve, and blood vessels. It is anticipated that these advanced therapies will prevent loss of life and reduce the likelihood of amputation, both for injured military personnel, and for civilian populations.

Microbion is also a recipient of a separate $2.5 million grant from USAMRMC, and is currently working closely with USAISR to develop an innovative topical antimicrobial therapeutic product to treat burns and complex, open military wounds. Dr. Brett Baker, the President and CEO of Microbion stated “Microbion’s goal in AFIRM is to develop lifesaving products, and to improve long-term quality of life of our wounded military personnel. The products being developed through collaborations within AFIRM and USAISR will benefit the treatment of extensive burns, infections, and a wide variety of other lifethreatening wounds.”

“This is big win for Montana’s biotech industry,” said Sen. Jon Tester, (D-Mont.) “It shows that our companies can play a vital role in some of the most cutting-edge research around. Working with the Defense Department on the AFIRM program, Microbion will be doing medical research that will make a real difference in troops’ lives.”

“This grant will help continue to grow Montana’s biotech industry and at the same time help our heroes, those serving in harms way if they are wounded,” said Governor Brian Schweitzer. “I commend the USAMRMC and Microbion for their innovative leadership.”

“Our consortium is comprised of a core of 15 advanced academic institutions, and approximately 20 leading edge corporate partners working in collaboration with USAISR,” Dr. Baker explained. The core academic institutions, led by Rutgers University and the Cleveland Clinic include: Case Western Reserve University, Carnegie Mellon University, SUNY Stony Brook, Dartmouth College, MIT, Massachusetts General Hospital/Harvard Medical School, the Mayo Clinic, and Vanderbilt University.

“This partnership will bring in good paying jobs to Montana, boost our economy and ensure Montana’s best and brightest can share their expertise in biotechnology,” said Senator Max Baucus (D-Mont.), chairman of the powerful Senate Finance Committee. “The work that AFIRM is doing is truly impressive and incredibly important, and Microbion is a perfect example of the innovative technology companies we have in Montana. Together they can find medical solutions that will ease the suffering and disability of our soldiers on the front lines and we owe our troops the best science can offer.”

Congressman Denny Rehberg (R-Mont.) also commented. “Private entities like Microbion play a critical role in developing cutting edge treatments for those who have been severely injured while bravely serving our country,” said Rehberg. “This funding is a recognition of those efforts. It’s great to see a Montana-based business playing a role in these crucial advancements.”

“Microbion Corporation is ideally suited to play a part in this initiative given their experience in both technology development and commercialization.” said John O’Donnell, TechRanch Executive Director.

Microbion relocated from Anchorage, Alaska to Bozeman, Montana early in 2005. “We immediately became an industrial member of the Center for Biofilm Engineering at Montana State University, a leading research institute in our field. Bozeman offered a highly advanced academic environment, small business development infrastructure, and a growing “critical mass” of biotechnology and pharmaceutical companies. Our medical research relationships with the military were initially facilitated by Ray Friesenhahn of MSU TechLink, to whom we owe a debt of gratitude.” Dr. Baker stated. “As a Bozeman company, we are very proud to participate in AFIRM, as we contribute to Montana’s growing presence in leading edge biotechnology, medical device, and pharmaceutical technologies.”

Uniquely Insidious: Yersinia pestis Biofilms

admin — Fri, 02 Apr 2010 13:53:16 +0000

Bubonic plague, one of history’s deadliest infections, is transmitted by fleas infected with Yersinia pestis. The bacteria can starve fleas by blocking their digestive tracts, which stimulates the insects to bite repeatedly and thereby infect new hosts. Direct examination of infected fleas, aided by in vitro studies and experiments with the nematode Caenorhabditis elegans, have established that Y. pestis forms a biofilm in the insect. The extracellular matrix of the biofilm seems to contain a homopolymer of N-acetyl-D-glucosamine, which is a constituent of many bacterial biofilms. A regulatory mechanism involved in Y. pestis biofilm formation, cyclic- di-GMP signaling, is also widespread in bacteria; yet only Y. pestis forms biofilms in fleas. Here, the historical background of bubonic plague is briefly described and recent studies investigating the mechanisms by which these unique and deadly biofilms are formed are discussed.

Reference:

Darby, Creg. Uniquely Insidious: Yersinia pestis biofilms (2008) Trends in Microbiology, 16(4):158-164.

Growth of Mycobacterium tuberculosis Biofilms Containing Free Mycolic Acids and Harbouring Drug-Tolerant Bacteria

admin — Wed, 31 Mar 2010 20:13:39 +0000

Successful treatment of human tuberculosis requires 6–9 months’ therapy with multiple antibiotics. Incomplete clearance of tubercle bacilli frequently results in disease relapse, presumably as a result of reactivation of persistent drug-tolerant Mycobacterium tuberculosis cells, although the nature and location of these persisters are not known. In other pathogens, antibiotic tolerance is often associated with the formation of biofilms – organized communities of surface-attached cells – but physiologically and genetically defined M. tuberculosis biofilms have not been described. Here, we show that M. tuberculosis forms biofilms with specific environmental and genetic requirements distinct from those for planktonic growth, which contain an extracellular matrix rich in free mycolic acids, and harbour an important drug-tolerant population that persist despite exposure to high levels of antibiotics.

Reference:

Ojha, AK, Baughn, AD, Sambandan, D, et al. Growth of Mycobacterium tuberculosis biofilms containing free mycolic acis and harbouring drug-tolerant bacteria (2008) Molecular Microbiology, 69(1):164-174.

Efficacy of Common Hospital Biocides with Biofilms of Multi-Drug Resistant Clinical Isolates

admin — Tue, 30 Mar 2010 20:17:17 +0000

The hospital environment is particularly susceptible to contamination by bacterial pathogens that grow on surfaces in biofilms. The effects of hospital biocides on two nosocomial pathogens, meticillin-resistant Staphylococcus aureus (MRSA) and Pseudomonas aeruginosa, growing as free-floating (planktonic) and adherent biofilm populations (sessile) were examined. Clinical isolates of MRSA and P. aeruginosa were grown as biofilms on discs of materials found in the hospital environment (stainless steel, glass, polyethylene and Teflon) and treated with three commonly used hospital biocides containing benzalkonium chloride (1 % w/v), chlorhexidine gluconate (4 % w/v) and triclosan (11 % w/v). Cell viability following biocide treatment was determined using an XTT assay and the LIVE/DEAD BacLight Bacterial Viability kit. The minimum bactericidal concentration (MBC) of all biocides for planktonic populations of both organisms was considerably less than the concentration recommended for use by the manufacturer. However, when isolates were grown as biofilms, the biocides were ineffective at killing bacteria at the concentrations recommended for use. Following biocide treatment, 0-11 % of cells in MRSA biofilms survived, and up to 80% of cells in P. aeruginosa biofilms survived. This study suggests that although biocides may be effective against planktonic populations of bacteria, some biocides currently used in hospitals are ineffective against nosocomial pathogens growing as biofilms attached to surfaces and fail to control this reservoir for hospital-acquired infection.

Reference:

Smith, K, and Hunter, IS. Efficacy of common hospital blocides with biofilms of multi-drug resistant clinical isolates (2008) Journal of Medical Microbiology, 57(8):966-973.

Biofilms in Chronic Wounds

admin — Mon, 29 Mar 2010 20:25:41 +0000

Chronic wounds including diabetic foot ulcers, pressure ulcers, and venous leg ulcers are a worldwide health problem. It has been speculated that bacteria colonizing chronic wounds exist as highly persistent biofilm communities. This research examined chronic and acute wounds for biofilms and characterized microorganisms inhabiting these wounds. Chronic wound specimens were obtained from 77 subjects and acute wound specimens were obtained from 16 subjects. Culture data were collected using standard clinical techniques. Light and scanning electron microscopy techniques were used to analyze 50 of the chronic wound specimens and the 16 acute wound specimens. Molecular analyses were performed on the remaining 27 chronic wound specimens using denaturing gradient gel electrophoresis and sequence analysis. Of the 50 chronic wound specimens evaluated by microscopy, 30 were characterized as containing biofilm (60%), whereas only one of the 16 acute wound specimens was characterized as containing biofilm (6%). This was a statistically significant difference (p < 0.001). Molecular analyses of chronic wound specimens revealed diverse polymicrobial communities and the presence of bacteria, including strictly anaerobic bacteria, not revealed by culture. Bacterial biofilm prevalence in specimens from chronic wounds relative to acute wounds observed in this study provides evidence that biofilms may be abundant in chronic wounds.

Reference:

James, G, Swogger, E, Wolcott, R, Pulcini, EL, et al. Biofilms in chronic wounds (2007) Wound Repair and Regeneration, 16:37-44.

Antibiotic Resistance of Bacteria in Biofilms

admin — Sun, 28 Mar 2010 20:28:08 +0000

Bacteria that adhere to implanted medical devices or damaged tissue can encase themselves in a hydrated matrix of polysaccharide and protein, and form a slimy layer known as a biofilm. Antibiotic resistance of bacteria in the biofilm mode of growth contributes to the chronicity of infections such as those associated with implanted medical devices. The mechanisms of resistance in biofilms are different from the now familiar plasmids, transposons, and mutations that confer innate resistance to individual bacterial cells. In biofilms, resistance seems to depend on multicellular strategies. We summarize the features of biofilm infections, review emerging mechanisms of resistance, and discuss potential therapies.

Reference:

Stewart, P.S. and J.W. Costerton. Antibiotic Resistance of Bacteria in Biofilms (2001) The Lancet, 358:135-138.

Biofilm Formation Ability of Listeria monocytogenes Isolates from Raw Ready-to-Eat Seafood

admin — Sat, 27 Mar 2010 20:28:40 +0000

Listeria monocytogenes is of great concern as a foodborne pathogen. Many ready-to-eat foods are widely contaminated with this organism and have caused listeriosis outbreaks and sporadic cases in many countries. In Japan, there is a high incidence of L. monocytogenes contamination, specifically in raw ready-to-eat seafood. Identical L. monocytogenes subtypes have been isolated repeatedly from samples of food manufactured at a given store or processing plant, and researchers suspected that certain L. monocytogenes isolates have formed biofilms at these sites. A microtiter plate biofilm formation assay was conducted, and all raw ready-to-eat seafood isolates tested were able to form biofilms to various degrees. Biofilm formation by L. monocytogenes isolates of lineage I was significantly greater (P = 0.000) than that by isolates of lineage II. However, isolates of clonal lineages formed different levels of biofilms, indicating that the ability to form a biofilm is affected positively or negatively by environmental factors.

Reference:

Takahashi, H, Miya, S, Igarashi, K, Suda, T, et al. Biofilm Formation Ability of Listeria monocytogenes Isolates from Raw Ready-to-Eat Seafood (2009) Journal of Food Protection, 72(7):1476-1480.