New method to distinguish between viral and bacterial infections

 

When patients complain of coughing, runny nose, sneezing and fever, doctors are often stumped because they have no fundamental tool to identify the source of the respiratory symptoms and guide appropriate treatments.

 

That tool might finally be on its way. In a study proving feasibility, researchers at Duke Health showed that their testing technology can accurately distinguish between a viral and a bacterial infection for respiratory illness - a critical difference that determines whether antibiotics are warranted. And, importantly, the test provided results in under an hour.

 

Researchers have developed a gene expression method that diverges from current diagnostic strategies, which focus on identifying specific pathogens. The current tests are time-consuming and can only identify a pathogen if it's specifically targeted by the test in the first place.

 

Host gene expression, however, looks for a distinct immune signal that is unique to the type of infection the body is fighting. The immune system activates one set of genes when fighting bacterial infections and a different set of genes in response to a viral infection. After the team discovered these gene expression signatures for bacterial and viral infection, they collaborated with BioFire Diagnostics, a company that specializes in molecular diagnostics, to develop this first-of-its kind test.

 

See:

 

Ephraim L. Tsalik, et al. Discriminating Bacterial and Viral Infection Using a Rapid Host Gene Expression Test. Critical Care Medicine, 2021; Publish Ahead of Print DOI: 10.1097/CCM.0000000000005085

 

Posted by Dr. Tim Sandle, Pharmaceutical Microbiology Resources (http://www.pharmamicroresources.com/)

Teixobactin - new antibiotic update

Scientists have produced new, effective and simplified forms of teixobactin - a new generation antibiotic which defeats multi-drug resistant infections such as MRSA - as part of a pioneering research effort to tackle antimicrobial resistance.

The team, led by Dr. Ishwar Singh at the University of Lincoln, UK, has pinpointed exactly which amino acid in the newly discovered teixobactin antibiotic makes it so successful at killing off harmful MRSA bacteria, which are resistant to many other antibiotics. The research team has adapted this rare molecule so that it can be easily used in the production of new drugs.

The breakthrough comes after the team successfully produced a number of synthetic derivatives of the highly potent teixobactin - hailed as a 'game-changer' in the fight against antimicrobial resistance - and became the first in the world to document its three-dimensional molecular make-up. These developments represent important steps to understanding how the powerful antibiotic functions and which building blocks are needed for it to work effectively.

Their newest study, which directly targets MRSA bacteria, overcomes a further barrier in the race to combat drug resistant bacteria.

Singh, a specialist in novel drug design and development from the University of Lincoln's School of Pharmacy, explained, "The scientific community has found it extremely difficult, time-consuming and expensive to synthetically produce the amino acid, enduracididine, which makes teixobactin so effective at killing a range of pathogens without detectable resistance.

"Teixobactin was first isolated from soil microorganisms (which do not grow under laboratory conditions) - the natural source of nearly all antibiotics developed since the 1940s - but in order for it to be developed as a potential treatment, several versions must be produced via chemical synthesis to overcome the hurdles of drug development. Last year we were successful in producing man-made forms of the antibiotic, but now we have increased its potency against MRSA. The key amino acid, enduracididine, is important for high potency but it has also been a bottleneck in the wider production of powerful teixobactin derivatives and their advancement as new drugs. We have now developed several potent molecules with very similar effects to natural teixobactin, and we believe this takes us a step closer towards the clinic."

MRSA is a type of bacteria that is resistant to many widely-used antibiotics, which means it is harder to treat than other infections. This 'superbug' mainly affects people who are staying in hospital and while they can usually be treated with certain antibiotics, concerns are growing around the world about the rate at which bacteria are developing resistance to existing drugs.

It has been predicted that by 2050 an additional 10 million people will succumb to drug resistant infections each year. The development of new antibiotics which can be used as a last resort when other drugs are ineffective is therefore a crucial area of study for healthcare researchers around the world.

The bacteria against which teixobactin is effective have, thus far, not shown any detectable resistance and given its mechanisms, scientists are also confident that resistance is unlikely to evolve in the future.

Singh is working with colleagues from the School of Life Sciences and the School of Chemistry at the University of Lincoln to develop teixobactin into a viable drug.

Dr. Edward Taylor, a lecturer in Life Sciences at Lincoln, said, "Antimicrobial resistance is spreading faster than the introduction of new antibiotics, which means there are major concerns about a possible health crisis. The recently discovered teixobactin has shown tremendous promise due to its potent activity, particularly against resistant pathogens such as MRSA, which is why it is the focus of important research here at Lincoln and around the world. Several other research groups substituted the rare enduracididine amino acid in teixobactin with commercially available building blocks, but the resulting products were much less active than the natural product. Our study aimed to find the most suitable replacement for this rare molecule, and we found that amino acids which have a similar structure and functional group were most effective."

The group found that three of the molecules they tested showed very promising activity against MRSA bacteria, and their research will now continue as they aim to produce several versions of teixobactin which could eventually become commercially available drugs.

The study is published in the Royal Society of Chemistry journal, Chemical Communications.

Breakthrough for Patient Safety in Healthcare Facilities

By Megan Ray Nichols

Infection control is one of the most important aspects of health care, and it’s often the most difficult to manage. No matter how carefully cleaned a room, table, or piece of equipment is, everyone who passes by or touches it is constantly shedding microbes and bacteria, making it is easy to contaminate even the most sterile environment. A new study in infection control and sanitation procedures may help change that, providing an entirely new level of patient protection.

Time Is of the Essence

There are quite a few effective procedures currently in place for patient protection and infection control. Strict hand hygiene rules, for example, reduce the patient-to-patient transmission of microbes, bacteria, and infections. Other techniques include environmental disinfection and a test for specific microbes or bacteria called point prevalence testing.

The big problem with this type of testing is the amount of time it takes. It utilizes a culture-and-swab technique to detect any potential pathogens. Collecting the swab only takes seconds, but it can take days or even weeks to grow a culture. While medical professionals wait for cultures to grow, a dangerous pathogen can spread throughout a facility.

Not Everything Is Disposable

One of the easiest ways to deal with bacterial flora in a medical facility is to use of sterile, single-use disposable tools and items — such as the swabs, scalpel blades, and needles you see every time you visit a doctor’s office. They’re designed to be properly discarded after each use.

What about the stuff that can’t be thrown away or tools that are not single use? There are 6 steps to follow to clean, sterilize, package and store items that are not disposable:

1. Cleaning: Doctors clean tools manually then, clean them again using ultrasonic cleaners or automatic washers.

2. Inspection: Hospital staff visually inspects tools both for cleanliness and to make sure they work properly.

3. Packaging: Tools need to be packed in pouches, wrapped, or stored in rigid containers prior to sterilization.

4. Sterilization: There are a variety of means to sterilize packaged tools. Steam autoclave sterilization is the most common method — it’s both successful and cost effective.

5. Storage: After sterilization, storage must be in an area that minimizes the chances of contamination. Low traffic areas in a temperature-controlled office are ideal for this.

6. Quality Control: Doctors use physical, biological, and chemical indicators ensure the tools remain sterile during storage and eventual use.

The Importance of Calibration

The successes of sterilization steps are heavily dependent on one important factor: whether the sterilization machine is functioning properly.

Let’s look at an autoclave machine as an example. Depending on the tools being sterilized, there are pressure, temperature, and time variables to consider when using an autoclave machine. Older machines might require you to set those variables manually, while newer computer controlled autoclaves set automatically, hence the need for equipment calibration.

When calibrating a machine, an engineer or the machine itself will run a series of tests to make sure that the pressure, temperature and time are all within acceptable parameters. Without calibration, you may find yourself using a less-than-sterile tool, wrongly assuming the autoclave functioned properly.

Advances in Sanitation Procedures

An ounce of prevention is worth a pound of cure — and that’s why a collection of Italian researchers spent time finding a way to more effectively detect potential problems in a medical environment. The key to this breakthrough comes from not focusing on the pathogens themselves, instead focusing on the entire microscopic ecology present anywhere there are human beings.

In this case, the researchers chose a dental office. Their test determined that the targeted microflora was present: mfDNA which lives in the mouth. They were also able to, after a surface was sterilized, determine if the sterilization was incomplete. The latter is something that traditional swab and culture tests fail to do.

The system isn’t perfect yet, but it’s most definitely a step in the right direction. With the proliferation of multi-drug resistant bacteria and viruses, advances in sanitation procedures and testing are vital to ensure that patients in any setting are as protected as possible.

Guest post by Megan Ray Nichols

Susceptibility Testing for MRSA with the PCR assay

A new article of interest:

Methicillin-resistant Staphylococcus aureus (MRSA) is a multi-drug resistant pathogen, which is responsible for increasing cases of serious diseases, including life-threatening diseases and nosocomial and community-acquired infections. Laboratory identification of MRSA is crucial and essential both for initiation of appropriate antimicrobial therapies and for effective infection control strategies that are designed to limit the spread of MRSA. In spite of the availability of commercial kits for MRSA detection in the market, the Clinical and Laboratory Standards Institute (CLSI) recommends the use of phenotypic methods, such as the disk diffusion method with oxacillin or with cefoxitin, as well as a serial dilution method with oxacillin. Nevertheless, some studies have shown that results obtained with such phenotypic methods are controversial. The aim of the study described in this paper was to comparatively evaluate the traditional susceptibility testing for MRSA with PCR as the gold standard assay. Analysis of collection (n = 68) isolates of Staphylococcus aureus revealed that the serial dilution method with oxacillin possessed the highest sensitivity (at 100%). In contrast, the disk diffusion methods with oxacillin and cefoxitin showed lower sensitivity (95.83%, 95% CI (78.81% - 99.30%)). Furthermore, the borderline value of zone inhibition diameters for cefoxitin might be considered as a risk, and they may give false-susceptible result.

The reference is:

Sandle, T., Azizov, I., Babenko, D., Lavrinenko, A., Chesca, A. (2014) Comparative Evaluation of Traditional Susceptibility Testing for MRSA with the PCR Approach, Advances in Microbiology, 4, 1204-1211 http://dx.doi.org/10.4236/aim.2014.416130

For a copy, please contact Tim Sandle



Posted by Tim Sandle

FDA Guidance: Hospital-Acquired Bacterial Pneumonia and Ventilator

The FDA has issued a new guidance document of interest to those working in healthcare. It is titled “Guidance for Industry Hospital-Acquired Bacterial Pneumonia and Ventilator- Associated Bacterial Pneumonia: Developing Drugs for Treatment.”

The introduction to the document reads:

“The purpose of this guidance is to assist sponsors and investigators in the clinical development of drugs for the treatment of hospital-acquired bacterial pneumonia (HABP) and ventilator associated bacterial pneumonia (VABP).2 Specifically, this guidance addresses the Food and Drug Administration’s (FDA’s) current thinking regarding the overall development program and clinical trial designs for drugs to support an indication for treatment of HABP and VABP. This draft guidance is intended to serve as a focus for continued discussions among the Division of Anti-Infective Products, pharmaceutical sponsors, the academic community, and the public.

This guidance was prepared with the general understanding that a noninferiority trial design evaluating patients who have HABP/VABP would be used to demonstrate effectiveness. This guidance revises the draft guidance for industry Hospital-Acquired Bacterial Pneumonia and Ventilator-Associated Bacterial Pneumonia: Developing Drugs for Treatment issued in November 2010. This guidance includes revisions to the primary efficacy endpoints, the enrollment criteria, the suggested primary efficacy analysis populations, and the noninferiority margin justification.”

To access the document, go to FDA

Thanks to Brian Matthews for the information.

Posted by Tim Sandle

Global strategies for the elimination of leprosy

Of the various ‘ancient diseases’, one of the longest lasting (and arguably notorious) is leprosy (leprosy was recognized in the ancient civilizations of China, Egypt and India). Notwithstanding its long history, the disease is one that should be relatively straightforward, with tangible political support, to eliminate as a global health concern. The current strategy is being implemented by the World Health Organization (WHO).

In a new paper, Tim Sandle reviews this strategy and additionally considers some of the current research into leprosy, focused on the areas of diagnosis and treatment.

The reference is:

Sandle, T. (2013). Global Strategies for Elimination of Leprosy: A Review of Current Progress, Journal of Ancient Diseases & Preventive Remedies, 1 (4): e112. doi: 10.4172/2329-8731.1000e112

For a copy of the paper, please contact Tim Sandle

Posted by Tim Sandle

Microbial diseases of Ancient Egypt: lessons for today

By comparing the ancient forms of diseases from Ancient Egypt with their contemporary equivalents, researchers can attempt learn how particular diseases evolved; what makes them so harmful; and possibly how to stop them. This field of paleopathology is becoming increasingly sophisticated, aided by advances to scientific techniques.

In a new paper, Tim Sandle presents an overview of recent research pertaining to the entwined concerns of paleopathology and Egyptology.

The reference is:

Sandle, T. (2013). Pharaohs and Mummies: Diseases of Ancient Egypt and Modern Approaches, Journal of Ancient Diseases & Preventive Remedies, 1 (4): e110. doi: 10.4172/2329-8731.1000e110

For a copy of the paper, please contact Tim Sandle

Posted by Tim Sandle

Where did syphilis come from?

Did Columbus bring the disease syphilis back with him from the New World, or was it in Europe all along? Katherine Wright, winner of the Wellcome Trust science writing prize 2013, has investigated this issue in a fascinating article.

Here is an excerpt, all about the spread of Treponema pallidum:

"As its many names attest, contemporaries of the first spread of syphilis did not know where this disease had come from. Was it indeed the fault of the French? Was it God's punishment on earthly sinners?
Another school of thought, less xenophobic and less religious, soon gained traction. Columbus's historic voyage to the New World was in 1492. The Italian soldiers were noticing angry chancres on their genitals by 1494. What if Columbus had brought the disease back to Europe with him as an unwelcome stowaway aboard the Pinta or the Niña?"

To read the full article, see The Guardian.

Posted by Tim Sandle

Screening for hospital pathogens

A new microfluidic device (for handling small volumes of fluids) has been developed by researchers to screen for hospital pathogens like Pseudomonas aeruginosa.

Pseudomonas aeruginosa is a bacterium common in soil and water; it has also been associated with hospital acquired infections. People with weakened immune systems are at a particular risk, especially from the disease cystic fibrosis (the forming thick layers of mucus in the lungs).

To help the diagnosis of the pathogen, MIT researchers have developed a new microfluidic device that could speed the monitoring of bacterial infections associated with cystic fibrosis and other diseases. The advantage with the device is that it can screen patient samples faster and with greater accuracy.

The microfluidic chip is etched with tiny channels, each resembling an elongated hourglass with a pinched midsection. Researchers injected bacteria through one end of each channel, and observed how bacterial cells travel from one end to the other. The cells were propelled by electrical forces. Depending on the type of bacterial cell, they either passed through the channel's narrow section or were trapped at the opening. By using this method, the researchers could screen which bacteria are pathogens and which are harmless.

To demonstrate the method, the researchers examined ordinary strains of P. aeruginosa, along with mutant strains that were missing certain genes required to make the dangerous pathogens. From their experiments, the researchers found that their device is able to distinguish benign bacterial cells from those that are more likely to be pathogenic.

The study was a collaboration between scientists at Ghent University, Belgium, and the University of Queensland, in Australia. The findings have been published in the journal PLOS One. The paper is called “Dielectrophoresis-Based Discrimination of Bacteria at the Strain Level Based on Their Surface Properties.”

Posted by Tim Sandle

Consideration for infection control

Infection control is one of the most important aspects of healthcare and is based on the objectives of preventing transmission of infection between patients, and on the prevention of patients from contracting nosocomial infections (hospital acquired infections).

To explore the main routes of contamination and to explore some of the preventative measures that can be adopted, Tim Sandle and Jennifer Sandle have written a review article for Arab Medical Hygiene.

The article considers surfaces, equipment, clothing, flooring, staff screening, staff training, vaccination, good building design, infection surveillance, hand sanitisation, and cleaning and disinfection.

The reference is:

Sandle, T. and Sandle, J. (2013). An Important Aspect of Healthcare: Outlining the many considerations of infection control, Arab Medical Hygiene, October 2013, pp34-39

For a copy, please contact Tim Sandle

Posted by Tim Sandle

Key concerns for infection control

Clostridium difficile and norovirus appear to be the main causes of concern for infection control professionals as we enter the winter months according to the latest survey. Conducted at Infection Prevention 2013, the survey revealed that 48% of the respondents highlighted C difficile as the primary cause of concern and 36% highlighted norovirus.

Carried out by Bioquell, a provider of no-touch infection control solutions to the healthcare industry, the survey of 170 infection control nurses and senior practitioners were asked to rank various pathogens in order of priority and also indicate any others that they were concerned about. The findings revealed that CPE (carbapenemase-producing Enterobacteriaceae) was becoming a major concern (19%). Additionally, Acinetobacter (2%), MRSA (4%) and VRE (4%) were further potential issues being faced by infection control teams.

For more details, see Hospital Pharmacy Europe.

Posted by Tim Sandle

Detergent choices for endoscope reprocessing

The first stage of endoscope cleaning involves the use of detergents. Without adequate cleaning, the disinfection stage will not be completed successfully and the risk of microbial survival becomes greater. There are two classes of detergent: enzymatic and non-enzymatic. There are advantages and disadvantages with each type, and the choice between them should be made by way of risk assessment.

In relation to the above, Tim Sandle has written an article for The ClinicalServices Journal.

Sandle, T. (2012). ‘Detergent choices for endoscope reprocessing’, The Clinical Services Journal, Volume 11, Issue 8, pp71-75

The article can be read on-line, although readers need to register with the journal beforehand. Go to Clinical Services Journal

Posted by Tim Sandle

Cleaning endoscopes

The cleaning of endoscopes is an important part of contamination control in hospitals and in avoiding the transmission of hospital acquired infections. Cleaning involves the use of detergents. The selection of detergents is an important one, with the choice centred on enzymatic and non-enzymatic types.

To explore the benefits and risks of using either enzymatic and non-enzymatic detergents, Tim Sandle has written an article for Infection Control. There reference is:

Sandle, T. (2012). Keeping in control: the use of detergents for endoscope cleaning, Infection Control, August 2012, pp4-5

For details see Infection Control



Posted by Tim Sandle

Hand Hygiene among Microbiological Laboratory Workers

An article by Popovska et al has been published by the Macedonian Journal of Medical Sciences. The article presents the experience of laboratorians in the Microbiology Department in the Clinical Center in Skopje in promoting proper hand hygiene by participating in a training course and implementation of WHO guidelines among laboratory staff. The article examines different types of microbiological monitoring to assess hand hygiene.

The reference is:

Popovska K, Zdravkovska M, Blazevska B, Icev K, Eftimovski G. Implementation of Proper Hand Hygiene among Microbiological Laboratory Workers Respectively to WHO Guidelines. Maced J Med Sci. 2012 Jul 31; 5(2):147-151

The article can be read on-line here.

Posted by Tim Sandle

Cleaning endoscopes: Considering the risks and benefits of enzymatic and non-enzymatic detergents

The cleaning of critical medical devices, such as endoscopes, is of great importance both in terms of protecting the patient and for preventing the transmission of hospital-acquired infections (HAIs). For the cleaning of endoscopes there are typically two different types of detergents which can be used – enzymatic and non-enzymatic. Each type of detergent has advantages and disadvantages, ranging from efficacies relating to the removal of contamination to low-level allergenic risks to the people responsible for cleaning and subsequent disinfection.

In order to understand how detergents clean and the important differences between enzymatic and non-enzymatic detergents, Tim Sandle has written an article for the journal ‘Inside Hospitals’. A copy of the article can be read on-line on the websites ‘Hospital Bulletin’ and ‘Inside Hospitals’.

These can be accessed here:

HospitalBulletin or

InsideHospitals 

The reference is:

Sandle, T. (2012). “Cleaning endoscopes: Considering the risks and benefits of enzymatic and non-enzymatic detergents”, Inside Hospitals, June 2012, pp14-15

Posted by Tim Sandle

The properties of antimicrobial bandages

The addition of anti-microbial substances to bandages to help combat wound infection is becoming increasingly common. Bandages are included in the regimen of therapy of superficial wounds. In an article written for Arab Medical Hygiene, Tim Sandle surveys the different types of antimicrobial compounds and different preparations of bandages.

Here is an extract:

“Different types of chemical coatings have been developed for bandages. In order to assess the effectiveness of the coatings experimental data must be gathered to show that the chemical, in contact with the bandage, can reduce a known number of microorganisms (as measured by a logarithmic reduction) and be effective against a range of different bacteria and fungi (clinically significant microorganisms). Techniques to demonstrate the antimicrobial properties include cultural methods like corrected zone of inhibition and the log reduction assay, and flow cytometry.”

To view or request the article, go to AMH

The reference is:

Sandle, T. (2012). “A silver lining? The use of antimicrobial bandages”, Arab Medical Hygiene, Issue 6, July 2012, pp19-25

Posted by Tim Sandle