Friday, 18 October 2019

Just how many pathogens are lurking in your washing machine?


Investigators have identified a washing machine as a reservoir of multidrug-resistant pathogens. The pathogens, a single clone of Klebsiella oxytoca, were transmitted repeatedly to newborns in a neonatal intensive care unit at a children's hospital. The transmission was stopped only when the washing machine was removed from the hospital.

The research has implications for household use of washers. Water temperatures used in home washers have been declining, to save energy, to well below 60°C (140°F), rendering them less lethal to pathogens. Resistance genes, as well as different microorganisms, can persist in domestic washing machines at those reduced temperatures, according to the report.

At the hospital where the washing machine transmitted K. oxytoca, standard screening procedures revealed the presence of the pathogens on infants in the ICU. The researchers ultimately traced the source of the pathogens to the washing machine, after they had failed to find contamination in the incubators or to find carriers among healthcare workers who came into contact with the infants.

The newborns were in the ICU due mostly to premature birth or unrelated infection.The clothes that transmitted K. oxytoca from the washer to the infants were knitted caps and socks to help keep them warm in incubators, as newborns can quickly become cold, even in incubators.


The investigators assume that the pathogens "were disseminated to the clothing after the washing process, via residual water on the rubber mantle [of the washer] and/or via the final rinsing process, which ran unheated and detergent-free water through the detergent compartment," implicating the design of the washers, as well as the low heat, according to the report. The study implies that changes in washing machine design and processing are required to prevent the accumulation of residual water where microbial growth can occur and contaminate clothes.

However, it still remains unclear how, and via what source the pathogens got into the washing machine. The infants in the intensive care units (ICU) were colonized, but not infected by K. oxytoca.

See: https://scitechdaily.com/warning-your-energy-efficient-washing-machine-could-be-harboring-dangerous-pathogens/

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Thursday, 17 October 2019

The Use of Microbiological Culture Media Article

Free-to-read article on microbial culture media best practices.

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Wednesday, 16 October 2019

E. coli detected in minutes by new technology


A discovery by researchers at the School of Life Sciences at the University of Warwick offers a new technology for detecting bacteria in minutes by 'zapping' the bacteria with electricity.
Testing clinical samples or commercial products for bacterial contamination typically takes days. During this time, they can cause significant damage; many infections can become life threatening very quickly if not identified and treated with appropriate antibiotics.

For example, 8% of people with severe blood infection sepsis will die for every hour of delay in proper treatment. More routine problems like urinary tract infections are difficult to diagnose and some people cannot get a clear answer about their symptoms due to difficulties with detecting low-level infections. Studies have found 20-30% of urinary tract infections are missed by dipstick tests used for detecting bacteria in the urine.

Scientists have discovered that healthy bacteria cells and cells inhibited by antibiotics or UV light showed completely different electric reactions. They made this discovery by combining biological experiments, engineering and mathematical modelling. The findings could lead to the development of medical devices which can rapidly detect live bacterial cells, evaluate the effects of antibiotics on growing bacteria colonies, or which could identify different types of bacteria and reveal antibiotic-resistant bacteria.

The researchers have an ambitious plan to deliver the technology to market to maximise social good and have founded a start-up company Cytecom to commercialise the idea. The company has been awarded a grant from Innovate UK, the national innovation funding agency. This governmental support accelerates the process and the devices will be available to researchers and businesses in the very near future.


See:

James P. Stratford, Conor L. A. Edwards, Manjari J. Ghanshyam, Dmitry Malyshev, Marco A. Delise, Yoshikatsu Hayashi, Munehiro Asally. Electrically induced bacterial membrane-potential dynamics correspond to cellular proliferation capacity. Proceedings of the National Academy of Sciences, 2019; 201901788 DOI: 10.1073/pnas.1901788116

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Tuesday, 15 October 2019

Techniques for Improving Drug Solubility


Solubility is one of the most important phenomena in chemistry, pharmaceuticals and any number of other disciplines and industries. In the development of drugs, the ability of a solvent to create a uniform, homogenous system is critical to ensure that drug achieves the desired effect in patients.

A guest post by Megan Ray Nichols

The following list provides a look at some of the more modern and common techniques for improving drug solubility and enhancing the human body's ability to absorb and use them.

1. Reduce Particle Sizes

Reducing the size of the drug particles themselves is one of the most straightforward techniques for improving the final compound's solubility. The smaller the particle, the more surface area is exposed, and the more it can interact with the solvent.

You can apply this principle in several ways. Here are some of the most common:

  • Comminution: These processes include grinding, vibrating or crushing the particles until they reach the desired size. This solution is not perfect, however, as the physical agitation may degrade the drug’s effectiveness.
  • Spray drying: Food and chemical manufacturing entities have long used spray drying, and it has more recently gained acceptance in the drug industries. Spray drying yields an amorphous material that is many times more soluble and bioavailable than its previous crystalline form.
  • Micronization: Modern techniques for micronization involve applying supercritical fluids — such as carbon dioxide — to drugs at high pressures. Supercritical fluids cannot exist in liquid or gas form above certain temperatures. As they pass through a solvent, supercritical fluids cause supersaturation and the homogenous precipitation of the desired particles.

The first two techniques employ physical-mechanical force, while micronization capitalizes on fluid energy. 

2. Hot Melt (Fusion)

The hot melt, or fusion, method is another simple and economical technique. While the term is widely associated with hot melt adhesives, the concept behind such products yields a similar effect when applied to pharmaceutical formulation. Two heated components become more than the sum of their parts.

In this technique, a drug mixture and a water-soluble carrier are both subjected to a heating element until they mix. From there, the mixture formed from the two is cooled rapidly in an ice bath while receiving agitation.

This process yields a solid mass ready to be crushed, sieved, combined with a tableting agent and then formed into tablets. For it to work properly, the drug must be sufficiently miscible — it must be able to mix with another substance in any proportion. When performed correctly, this method improves the cycle time compared to other techniques, including spray drying.


3. Ultra-Rapid Freezing

Ultra-rapid freezing (URF) is one of several techniques based on the principles of cryogenics and lyophilization. It involves applying a thin film of a drug compound to a cryogenic substrate —a frozen surface. This process instantly freezes the drug.

During URF, the drug undergoes lyophilization. This part of the freeze-drying method involves removing water and solvent from the drug compound using a vacuum, changing them from their solid forms directly into their gaseous forms without first becoming a liquid.

The result is nanostructured powdered particles of the desired drug compound, each with improved surface area and high bioavailability.


4. Nanosuspension

Nanosuspension offers efficient delivery of especially hydrophobic and oleophobic drug compounds — drugs that are poorly soluble in both water and oil. Without nanosuspension, the resulting drug would have very low bioavailability and would not achieve the desired medical effect.

The process relies on surfactants. When dissolved in water, surfactants displace air on the surface of powders and particles and allow them to disperse more evenly within a liquid carrier. Surfactants stabilize and homogenize nanosized particles of topical or oral drug compounds within a carrier that they would normally not mix well with.

More than 40% of new chemical entities (NCEs) in drug discovery today are insoluble in water. However, nanosuspension using surfactants allows research and development on these difficult compounds to move forward. 

The Key to Consistency and Effectiveness

This list of available techniques is not exhaustive, and some may be used in conjunction with others. Improving drug solubility is key for reducing the number of dosages required by the patient and ensuring consistent performance of the drug in each case — whether the drug is intended for use in capsules, liquids or immediate- or timed-release formulations.


Monday, 14 October 2019

Digital Transformation of Pharmaceuticals and Healthcare


As with other sectors of the economy, pharmaceuticals and healthcare is undergoing digital transformation and with some companies this is continuing at a rapid pace as companies attempt to mine the sources of data available.

For those involved with the industry, this means an array of new abbreviations, initialism and acronyms to learn. Terms such as: artificial Intelligence, machine learning, internet-of-things (or the ‘industrial’ internet-of-things -IIOT), blockchain, augmented reality, predictive analytics, big data analytics, Industry 4.0 (or Industry X.0), digital twins, and telehealth are becoming part of the modern manufacturing lexicon.

Tim Sandle has written an new article:

Industry 4.0 is the subset of the fourth industrial revolution and it concerns the digital age and the interconnected manufacturing process, plus design of new products and controlling distribution. The route to get there is through digital transformation; and this process has many journeys, ways of thinking and different technologies, which include those centered on smart manufacturing, such as cyber-physical systems, the internet of things, cloud computing, and artificial intelligence. Central to all of this is data and the value that can be drawn from data, either for gaining real-time metrics about operations, production, inventory control, and quality data; to controlling the supply chain (such as through blockchain, which is a digital ledger); and using data for the purposes of predictive analytics.

The reference is:

Sandle, T. (2019): Digital Transformation of Pharmaceuticals and Healthcare, Institute of Validation Technology Blog, published July 2019.

To access, see: http://www.ivtnetwork.com/article/digital-transformation-pharmaceuticals-and-healthcare

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Sunday, 13 October 2019

FDA - Biological Product and HCT/P deviation reports annual summary for fiscal year 2018


The U.S. FDA requires reporting of certain deviations and unexpected events in manufacturing in accordance with 21 CFR 600.14, 606.171 or 1271.350(b).  The following manufacturers, who had control over the product when an event associated with manufacturing (deviation or unexpected event) occurred, are required to submit Biological Product Deviation (BPD) reports to the Center for Biologics Evaluation and Research (CBER), if the safety, purity, or potency of a distributed product may be affected.


This annual summary report provides an overview of the reports received by FDA during the fiscal year, including detailed information regarding the number and types of deviation reports received. Each firm responsible for reporting biological product and HCT/P deviations needs to use this information in evaluating their own deviation management program.

The current review can be found here: https://www.fda.gov/media/129692/download

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Saturday, 12 October 2019

Draft ISO 14644-17 Particle deposition rate applications


A new part of the ISO 14644 series is in development – ‘ISO/DIS 14644-17
Cleanrooms and associated controlled environments -- Part 17: Particle deposition rate applications’.

The standard focuses on particle deposition applications, and covers the missing information in existing documents. This new chapter could be applied in many industries such as assembly of microelectronic like sensors and actuator, displays and batteries, optical devices, space industry, automotive, medical devices, and in processes dealing with microbiological contamination.


The new document can be used as a standard in combination with the existing cleanroom standards (ISO 14644 and ISO 14698), and completes coverage of the range of particles that can cause unwanted surface contamination.

The focus is with the particle deposition rate level (PDRL), which is the particle deposition rate (cumulative number of particles per sqm per hour) times the observed particle size D divided by 10.

See: https://www.iso.org/standard/70606.html

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Analytical Quality by Design (AQbD): questions and answers


The MHRA has issued a feature on the application of Analytical Quality by Design to pharmacopoeial standards.


Analytical Quality by Design (AQbD) takes a structured approach to the development of analytical procedures which are fit for purpose and that consistently deliver results that meet predefined objectives. It achieves this through a detailed understanding of all aspects of the analytical methods performance ensuring adequate control and an ability to react to changes which can affect the quality of results.

Then review takes the form of a Q&A, which can be accessed here: https://mhrainspectorate.blog.gov.uk/2019/08/21/analytical-quality-by-design-aqbd-questions-and-answers/

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Friday, 11 October 2019

NIAID Officials Call for Innovative Research on Sexually Transmitted Infections


National Institute of Allergy and Infectious Diseases (NIAID) experts call for a renewed focus on sexually transmitted infections. Rates of gonorrhea, syphilis, and chlamydia are all on the rise, and some STIs are developing resistance to common treatments. In a new perspective piece in The Journal of Infectious Diseases, NIAID officials write that biomedical research establishments must work together to develop better diagnostics, treatments and vaccine candidates for STIs.

The perspective piece was written by NIAID Director Anthony S. Fauci, M.D., Robert W. Eisinger, Ph.D., special assistant for scientific projects in NIAID’s Immediate Office of the Director, and Emily Erbelding, M.D., director of NIAID’s Division of Microbiology and Infectious Diseases. The authors note that a variety of STIs are contributing to the public health crisis as cases of gonorrhea, syphilis, and chlamydia are all on the rise. Left untreated, many STIs can cause serious complications. Congenital syphilis can cause stillbirths and health complications in newborns, and gonorrhea and chlamydia can contribute to life-threatening ectopic pregnancies (when a fertilized egg grows outside the uterus). Gonorrhea and syphilis, which are increasing among men who have sex with men and bisexual men, also are associated with an increased risk for HIV transmission and acquisition. Moreover, increasing antimicrobial resistance will make STIs only more difficult to treat, as many existing drugs will become less effective against the microbes that cause gonorrhea and other STIs.


Unfortunately, the authors note, STI research efforts have not adequately addressed the ongoing spread of these diseases. To address this public health threat, biomedical research programs need to be refocused on developing innovative diagnostics, therapeutics, and vaccines for STIs. Healthcare providers need access to faster, low-cost diagnostics to identify both active and asymptomatic STIs. The STI vaccine pipeline also needs to produce effective new candidate vaccines for syphilis, gonorrhea, and chlamydia. As for STI therapeutics, the authors note that research efforts must focus on drug-drug interactions, toxicities and side effects, while keeping ahead of spreading antimicrobial resistance.

See:  https://www.niaid.nih.gov/news-events/niaid-officials-call-innovative-research-sexually-transmitted-infections?utm_campaign=+39719144&utm_content=&utm_medium=email&utm_source=govdelivery&utm_term

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Thursday, 10 October 2019

Newly discovered microbe degrades oil to gas


Crude oil and gas naturally escape from the seabed in many places known as "seeps." There, these hydrocarbons move up from source rocks through fractures and sediments towards the surface, where they leak out of the ground and sustain a diversity of densely populated habitats in the dark ocean. A large part of the hydrocarbons, primarily alkanes, is already degraded before it reaches the sediment surface. Even deep down in the sediment, where no oxygen exists, it provides an important energy source for subsurface microorganisms, amongst them some of the so-called archaea.

These archaea were good for many surprises in recent years. Now a study led by scientists from the Max Planck Institute for Marine Microbiology in Bremen, Germany, and the MARUM, Centre for Marine Environmental Sciences, provides environmental information, genomes and first images of a microbe that has the potential to transform long-chain hydrocarbons to methane. Their results are published in the journal mBio.
Splitting oil into methane and carbon dioxide

This microbe, an archaeon named Methanoliparia, transforms the hydrocarbons by a process called alkane disproportionation: It splits the oil into methane (CH4) and carbon dioxide (CO2). Previously, this transformation was thought to require a complex partnership between two kinds of organisms, archaea and bacteria. Here the team from Max Planck Institute for Marine Microbiology and MARUM presents evidence for a different solution.


During a cruise in the Gulf of Mexico, the scientists collected sediment samples from the Chapopote Knoll, an oil and gas seep, 3000 m deep in the ocean. Back in the lab in Bremen, they carried out genomic analyses that revealed that Methanoliparia is equipped with novel enzymes to use the quite unreactive oil without having oxygen at hand.

With the combined enzymatic tools of both relatives, Methanoliparia activates and degrades the oil but forms methane as final product. Moreover, the visualization of the organisms supports the proposed mechanism: Microscopy shows that Methanoliparia cells attach to oil droplets.

Methanogenic microorganisms have been important for the earth's climate through time as their metabolic product, methane, is an important greenhouse gas that is 25 times more potent than carbon dioxide.

See:

Rafael Laso-Pérez, Cedric Hahn, Daan M. van Vliet, Halina E. Tegetmeyer, Florence Schubotz, Nadine T. Smit, Thomas Pape, Heiko Sahling, Gerhard Bohrmann, Antje Boetius, Katrin Knittel, Gunter Wegener. Anaerobic Degradation of Non-Methane Alkanes by “Candidatus Methanoliparia” in Hydrocarbon Seeps of the Gulf of Mexico. mBio, 2019; 10 (4) DOI: 10.1128/mBio.01814-19

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Wednesday, 9 October 2019

E. coli's secret weapon in launching infections


Most types of Escherichia coli are harmless, but the ones that aren't can cause severe life-threatening diarrhea. These problematic bacteria launch infections by inducing intestinal cells to form tiny structures, called pedestals, that anchor the pathogens in place and help the colonies grow.

Microbiologists have described an Achilles heel for disabling pedestal formation. Lab experiments on enteropathogenic and enterohemorrhagic E. Coli (EPEC and EHEC) showed that when the pathogens were prevented from injecting a protein called EspG into intestinal hosts, the hosts were slower and less effective in producing pedestals that fixed the bacteria in place. Further investigations revealed the cellular pathways hijacked by EspG.

The findings can help reveal the mechanics of infection and suggest new avenues of treatment. Worldwide, more than 500,000 children die every year from diarrheal diseases, and pathogenic strains of E. Coli are among the most common causes, according to the World Health Organizations. But treating these infections can be tricky. Using antibiotics to treat a person with EHEC, for example, can trigger the bacteria to release Shiga toxin, which can lead to a life-threatening infection similar to sepsis.

Researchers have long known that pathogenic E. coli injects its host with a variety of proteins, including EspG. Until now, however, those interactions have been linked only to other biochemical functions.

Previously, the researchers studied the effects of EspG on macrophages, and those findings suggested the protein may have an overlooked role in pedestal formation with intestinal hosts.
For the current study, they infected one group of Hap1 cells with wild-type EHEC and EPEC, and infected another with the same types of E. Coli, but lacking the genes responsible for producing EspG. Using fluorescence microscopy, the researchers studied the results. The cells infected by E. Coli lacking EspG took longer to produce pedestals the those by wild-type strains, and what pedestals were produced were shorter.


Follow up experiments revealed that the EspG protein hijacks the host cell by scavenging an active enzyme called PAK. Although previous work has shown a link between EspG and PAK, the new study is the first to connect the two to the formation of pedestals. That connection may help researchers studying other diseases, as well. PAK has been implicated in some cancers, and other studies have shown that some viruses -- including HIV -- can activate it.

See:

Vikash Singh, Anthony Davidson, Peter J. Hume, Vassilis Koronakis. Pathogenic Escherichia coli Hijacks GTPase-Activated p21-Activated Kinase for Actin Pedestal Formation. mBio, 2019; 10 (4) DOI: 10.1128/mBio.01876-19

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Tuesday, 8 October 2019

Killer of algae production - Vampirovibreo chlorellovorus - new DNA analysis

New DNA analysis has found genetic diversity in Vampirovibrio chlorellevorus, complicating efforts to protect algae ponds and the biofuels industry from this destructive pest
New DNA analysis has revealed surprising genetic diversity in a bacterium that poses a persistent threat to the algae biofuels industry. With the evocative name Vampirovibrio chlorellevorus, the predatory pest sucks out the contents of the algae cells (thus the vampire reference) and reduces a productive, thriving, green algae pond to a vat of rotting sludge.

“DNA sequences show what are likely different species, suggesting a much larger diversity in this family than we originally assumed,” said Blake Hovde, a Los Alamos National Laboratory biologist. “That means the treatment for one algae pest might not work for another, which can be a big problem for large-scale algae cultivation in the future.”

The research team sequenced two strains of Vampirovibrio from the same pond. The two samples collected one year apart came from an outdoor algae cultivation system in the Sonoran Desert of Arizona run by University of Arizona collaborators Seth Steichen and Judith Brown. The team sequenced and analyzed the genomes to identify the genes involved in predation, infection and cell death of the valuable Chlorella algae that the bacterium targets.

“Our genomic analyses identified several predicted genes that encode secreted proteins that are potentially involved in pathogenicity, and at least three apparently complete sets of virulence (Vir) genes,” Hovde said. Those genes are characteristic of bacteria that carry out cell invasion.

With Chlorella algae valued as a key source of harvestable biomass for biofuels and bioproducts, it is extremely useful to be able to enhance the fundamental understanding of interactions between a unique bacterial pathogen and its green algal host, Hovde noted. The results of this research have direct relevance to the success of large-scale commercial algal production projects underway to advance U.S. energy security (biofuels) and the production of aquaculture feedstocks and algal-based nutraceuticals.

For future work, the team is following up with a project with the Joint Genome Institute to characterize six more pest genomes from the same family to see if the diversity of these organisms continues to expand, or if the researchers can start categorizing these pests into species groups.

Publication: “Vampirovibrio chlorellavorus draft genome sequence, annotation, and preliminary characterization of pathogenicity determinants“ in Phycological Research, https://doi.org/10.1111/pre.12392
Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Monday, 7 October 2019

How to switch from ‘bad science’ to ‘good science’ (article)



There are many excellent science studies based on well-designed experiments and which make reasoned claims based on the assembled experimental data. While the majority of scientific findings and papers issued each year offer valid findings and make a contribution to the body of knowledge, there are, unfortunately, many cases of ‘bad science’ out there.

Another concern is that outcomes from science papers are sometimes misinterpreted or they are overly exaggerated by the media. This is perhaps reflective of society increasingly seeking quick answers. The reality of science is that progress is invariably slow, based on incremental findings, and occasional contradictions.

Tim Sandle has written an article looking at bad science, good science together with some tips for writing an effective science article.


This article examines what makes for bad science and how bad science occurs, and then contrasts this with some examples of good science. The article also provides advice on what makes for a good science paper and for those wishing to try their hand at writing a science article, advice as to how to approach this is provided.

The reference is:

Sandle, T. (2019) How to switch ‘bad science’ for ‘good science’? (and what makes for a good science paper and how to approach writing a science article), The Journal (Institute of Science and Technology), Summer 2019, pp14-20

To view a copy, see: https://www.researchgate.net/publication/334598499_How_to_switch_'bad_science'_for_'good_science'

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Sunday, 6 October 2019

Foodborne pathogen sheltered by harmless bacteria that support biofilm formation


Pathogenic bacteria that stubbornly lurk in some apple-packing facilities may be sheltered and protected by harmless bacteria that are known for their ability to form biofilms, according to Penn State researchers, who suggest the discovery could lead to development of alternative foodborne-pathogen-control strategies.

That was the key finding that emerged from a study of three tree-fruit-packing facilities in the Northeast where contamination with Listeria monocytogenes was a concern. The research, done in collaboration with the apple industry, was an effort to better understand the microbial ecology of food-processing facilities. The ultimate goal is to identify ways to improve pathogen control in the apple supply chain to avoid foodborne disease outbreaks and recalls of apples and apple products.

In the study, researchers sought to understand the composition of microbiota in apple-packing environments and its association with the occurrence of the foodborne pathogen Listeria monocytogenes. Their testing revealed that a packing plant with a significantly higher Listeria monocytogenes occurrence was uniquely dominated by the bacterial family Pseudomonadaceae and the fungal family Dipodascaceae.


Biofilms are a collection of microorganisms that attach to a surface and then secrete a slimy material that slows down the penetration of cleaners and sanitizers. The findings of the research provide insight into the Listeria contamination problem and may lead to researchers and the apple industry getting closer to solving it.

The challenge presented by microbiota possibly sheltering Listeria monocytogenes is not limited to fruit-processing facilities or produce, Penn State researchers suspect.

See:

Xiaoqing Tan, Taejung Chung, Yi Chen, Dumitru Macarisin, Luke LaBorde, Jasna Kovac. The occurrence of Listeria monocytogenes is associated with built environment microbiota in three tree fruit processing facilities. Microbiome, 2019; 7 (1) DOI: 10.1186/s40168-019-0726-2

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

Saturday, 5 October 2019

Why initial UTIs increase susceptibility to further infection


More than 60% of women will experience a urinary tract infection (UTI) at some point in their lives, and about a quarter will get a second such infection within six months, for reasons that have been unclear to health experts.


Now, researchers at Washington University School of Medicine in St. Louis have discovered that an initial infection can set the tone for subsequent infections. In mouse studies, the researchers found that a transient infection triggers a short-lived inflammatory response that rapidly eliminates the bacteria. But if the initial infection lingers for weeks, the inflammation also persists, leading to long-lasting changes to the bladder that prime the immune system to overreact the next time bacteria find their way into the urinary tract, worsening the infection.

To understand why some people are more prone to severe, recurrent infections than others, Hannan and co-senior author Scott J. Hultgren, PhD, the Helen L. Stoever Professor of Molecular Microbiology -- along with co-first authors Lu Yu, PhD, and Valerie O'Brien, PhD, both graduate students when the work was conducted -- infected a strain of genetically identical mice with E. coli, the most common cause of UTIs in people. The strain can have widely divergent responses to bacterial bladder infections. Some eliminate the bacteria within a few days; others develop chronic infections that last for weeks.

The researchers infected these mice with E. coli, monitored them for signs of infection in their urine for four weeks, and then gave them antibiotics. After giving the mice a month to heal, the researchers infected them again. For comparison, they also infected a separate group of mice for the first time.

All the previously infected mice mounted immune responses more rapidly than the mice infected for the first time. The ones that had cleared the infection on their own the first time around did so again, eliminating the bacteria even faster than before. But the mice that failed to clear the infection the first time did much worse, despite the speed of their immune responses. A day after infection, 11 out of 14 had more bacteria in their bladders than they had started with, and many went on to again develop chronic infections that lasted at least four weeks.

The difference lay in an immune molecule called TNF-alpha that coordinates a powerful inflammatory response to infection, the researchers discovered. Both sets of mice turned on TNF-alpha within six hours of infection. But the mice that controlled the infection turned off TNF-alpha again within 24 hours, allowing the inflammation to resolve. In the mice with prolonged initial infections, TNF-alpha stayed on, driving persistent inflammation and triggering a change to the patterns of gene activity in immune cells and the cells of the bladder wall.

To find out, the researchers took mice that had recovered from initial prolonged UTIs and depleted their TNF-alpha before re-infecting them with bacteria. Without TNF-alpha driving excessive inflammation, the mice fared better, significantly reducing the number of bacteria in their bladders within a day of infection.


The findings suggest that targeting TNF-alpha or another aspect of the inflammatory response that causes bladder tissue damage during acute infection may help prevent or alleviate recurrent UTIs, the researchers said.

See:

Lu Yu, Valerie P O'Brien, Jonathan Livny, Denise Dorsey, Nirmalya Bandyopadhyay, Marco Colonna, Michael G Caparon, Elisha DO Roberson, Scott J Hultgren, Thomas J Hannan. Mucosal infection rewires TNFɑ signaling dynamics to skew susceptibility to recurrence. eLife, 2019; 8 DOI: 10.7554/eLife.46677

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology

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