Antimicrobial activity of silver-treated bacteria

A new paper, with a contribution from Tim Sandle, has been published looking into a novel application of silver as an antimicrobial.

Silver is a potent antimicrobial agent against a variety of microorganisms and once the element has entered the bacterial cell, it accumulates as silver nanoparticles with large surface area causing cell death. At the same time, the bacterial cell becomes a reservoir for silver. This study aims to test the microcidal effect of silver-killed E. coli O104: H4 and its supernatant against fresh viable cells of the same bacterium and some other species, including E. coli O157: H7, Multidrug Resistant (MDR) Pseudomonas aeruginosa and Methicillin Resistant Staphylococcus aureus (MRSA).

Silver-killed bacteria were examined by Transmission Electron Microscopy (TEM). Agar well diffusion assay was used to test the antimicrobial efficacy and durability of both pellet suspension and supernatant of silver-killed E. coli O104:H4 against other bacteria. Both silver-killed bacteria and supernatant showed prolonged antimicrobial activity against the tested strains that extended to 40 days.

The presence of adsorbed silver nanoparticles on the bacterial cell and inside the cells was verified by TEM. Silver-killed bacteria serve as an efficient sustained release reservoir for exporting the lethal silver cations. This promotes its use as a powerful disinfectant for polluted water and as an effective antibacterial which can be included in wound and burn dressings to overcome the problem of wound contamination.

The reference is:

Mohamed, D. S., El-Baky, R.M.A, Sandle, T., Mandour, S. A. and Ahmed, E. F. (2020) Antimicrobial Activity of Silver-Treated Bacteria against other Multi-Drug Resistant Pathogens in Their  Environment, Antibiotics, 9 (4),181: https://doi.org/10.3390/antibiotics9040181

The paper can be accessed here: https://www.mdpi.com/2079-6382/9/4/181

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

Modern myth #7: Gloves

Only natural latex gloves can give me an allergy.

Chemical allergy is more commonly encountered than natural latex allergy, but is often confused with the latter. With natural latex and nitrile gloves, chemical allergy is frequently derived from the accelerators (e.g. thiazoles, dithiocarbamates, thiurams etc) that are used in the vulcanisation process.  Plasticisers such as phthalates are often found in vinyl gloves and can also trigger a chemical allergy.

All nitrile gloves offer the same chemical resistance.

With nitrile offering a broad range of chemical protection, this glove material is often selected where chemical exposure is a concern. In the face of increasing price pressure and perhaps also to give users latex-like comfort, manufacturers have been steadily reducing the thickness of their gloves. If we look at the palm thickness – the part of the glove that is most likely to be in contact with chemical exposure – then the thickness of nitrile gloves may vary from 0.07mm to 0.14mm. With such a wide variation in palm thickness, comes varying levels of chemical protection. Sp, not all nitrile gloves offer the same level of protection. Seek out data on palm thickness and even better ask a glove manufacturer to provide glove-specific chemical data.

All gloves have the same barrier properties.

Gloves are often worn as a barrier for personal protection or for process protection and often for both. Prior to use, gloves may exhibit equivalent barrier properties as defined by AQL. The latter refers to the statistical probability of holes in the gloves. In-use, glove material, thickness, degradation etc. will influence the potential to develop holes. A simulated use study by Kerr revealed failure rates of respectively 35% and 9% in vinyl and latex. To assess the barrier performance of your gloves, you can perform your own test by wearing a pair for a defined time then filling them up with water to see whether they leak.

Selecting gloves is a complex business and the huge diversity in glove choices does not make it easy. We have discussed a range of topical subjects which may cloud judgement. Hopefully a better understanding of the realities surrounding glove myths will contribute to selecting the correct glove for particular applications.

See: https://www.pharmamicroresources.com/2015/09/lab-gloves-myths-and-realities.html

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

Buying Antibiotics Online in the UK: What You Need to Know

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The online pharmaceutical industry is under scrutiny after a 2017 study showed that nearly half of 20 online pharmacies observed don’t ask for a prescription when selling antibiotics. This practice can seriously impact the effort of the medical community to prevent microbial resistance due to the improper use of antibiotics.

What is the legal requirement to sell medication online in the UK?

The law requires every online medicine dispensary to register with MHRA and GPhC. These agencies regulate the selling and distribution of drugs to consumers. Of course, anytime you want to buy antibiotics online, if the store isn’t registered with any of these agencies, it should be a red flag that warns buyers about unethical pharmaceutical practices.

Fortunately, it doesn’t appear to be dire for all consumers. There are plenty of online pharmacies that ensure to require buyers to present their prescription before selling any prescription medication. There are also several ways by which an online pharmacy can verify the suitability of selling antibiotic and other prescription meds to a consumer.

·         Some online pharmacies let customers choose the dosage, type, and treatment duration when buying antibiotics. This process is dangerous as it puts the consumers at risk. Without a doctor’s script, they could end up taking too much or too little of the right medicine.

·         There are online pharmacies that use a process where the consumer can click on symptoms, and the website will direct them to the type of antibiotic to buy before checking out. Once again, this process is dangerous and very subjective.

·         The right process involves allowing the consumer to fill out a questionnaire which will be evaluated by a doctor who will assess the consumer’s suitability to buy antibiotics.

In addition to a questionnaire, online pharmacies also need to educate the consumer about the proper and safe use of antibiotics. There needs to be detailed information on potential side effects, especially when taken along with other prescription medication.

What results from improper use of antibiotics?

Improper use of antibiotics results in microbial resistance. Microbes often mutate and develop resistance to a medication when the patient doesn’t take the right dosage or complete the recommended treatment period. We’ve all heard about superbugs which no longer respond to common antibiotics available today. Unfortunately, getting infected by antibiotic-resistant microbes is fatal as there’s no medication available to treat the patient. Also, it will take time for researchers to discover new antibiotics that can cure these new infections.

The problem with common infections is the misconception that when you’re no longer experiencing symptoms, you can stop taking medication. Also, many people today tend to self-medicate based on the limited information they find online.

The bottom line

Online pharmacies are available to provide consumers with a more convenient way to buy medication. But, consumers should exercise caution and be more conscious about protecting their health. Although it’s easy to research symptoms online, these aren’t as accurate as visiting a doctor and getting a thorough examination. If you want to buy antibiotics online, make sure to obtain a prescription first and buy from a pharmacy registered with health regulatory agencies.

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