Quantitative assessment of the germicidal efficacy of ultrasonic energy

Biofilm formation by Listeria monocytogenes from the meat processing industry environment and the use of different combinations of detergents, sanitizers, and UV-A radiation to control this microorganism in planktonic and sessile forms

This study aimed to evaluate the ability of biofilm formation by L. monocytogenes from the meat processing industry environment, as well as the use of different combinations of detergents, sanitizers, and UV-A radiation in the control of this microorganism in the planktonic and sessile forms. Four L. monocytogenes isolates were evaluated and showed moderate ability to form biofilm, as well as carried genes related to biofilm production (agrB, agrD, prfA, actA, cheA, cheY, flaA, sigB), and genes related to tolerance to sanitizers (lde and qacH). The biofilm-forming isolates of L. monocytogenes were susceptible to quaternary ammonium compound (QAC) and peracetic acid (PA) in planktonic form, with minimum inhibitory concentrations of 125 and 75 ppm, respectively, for contact times of 10 and 5 min. These concentrations are lower than those recommended by the manufacturers, which are at least 200 and 300 ppm for QAC and PA, respectively. Biofilms of L. monocytogenes formed from a pool of isolates on stainless steel and polyurethane coupons were subjected to 14 treatments involving acid and enzymatic detergents, QAC and PA sanitizers, and UV-A radiation at varying concentrations and contact times. All treatments reduced L. monocytogenes counts in the biofilm, indicating that the tested detergents, sanitizers, and UV-A radiation exhibited antimicrobial activity against biofilms on both surface types. Notably, the biofilm formed on polyurethane showed greater tolerance to the evaluated compounds than the biofilm on stainless steel, likely due to the material's surface facilitating faster microbial colonization and the development of a more complex structure, as observed by scanning electron microscopy. Listeria monocytogenes isolates from the meat processing industry carry genes associated with biofilm production and can form biofilms on both stainless steel and polyurethane surfaces, which may contribute to their persistence within meat processing lines. Despite carrying sanitizer tolerance genes, QAC and PA effectively controlled these microorganisms in their planktonic form. However, combinations of detergent (AC and ENZ) with sanitizers (QAC and PA) at minimum concentrations of 125 ppm and 300 ppm, respectively, were the most effective.

Optimizing the use of low-frequency ultrasound for bacterial detachment of in vivo biofilms in dental research-a methodological study

OBJECTIVES

Low-frequency, low-intensity ultrasound is commonly utilized in various dental research fields to remove biofilms from surfaces, but no clear recommendation exists in dental studies so far. Therefore, this study aims to optimize the sonication procedure for the dental field to efficiently detach bacteria while preserving viability.

MATERIALS AND METHODS

Initial biofilm was formed in vivo on bovine enamel slabs (n = 6) which were worn by four healthy participants for 4 h and 24 h. The enamel slabs covered with biofilm were then ultrasonicated ex vivo for various time periods (0, 1, 2, 4, 6 min). Colony-forming units were determined for quantification, and bacteria were identified using MALDI-TOF. Scanning electron microscopic images were taken to also examine the efficiency of ultrasonications for different time periods.

RESULTS

Ultrasonication for 1 min resulted in the highest bacterial counts, with at least 4.5-fold number compared to the non-sonicated control (p < 0.05). Most bacteria were detached within the first 2 min of sonication, but there were still bacteria detached afterwards, although significantly fewer (p < 0.0001). The highest bacterial diversity was observed after 1 and 2 min of sonication (p < 0.03). Longer sonication periods negatively affected bacterial counts of anaerobes, Gram-negative bacteria, and bacilli. Scanning electron microscopic images demonstrated the ability of ultrasound to desorb microorganisms, as well as revealing cell damage and remaining bacteria.

CONCLUSIONS

With the use of low-frequency, low-intensity ultrasound, significantly higher bacterial counts and diversity can be reached. A shorter sonication time of 1 min shows the best results overall.

CLINICAL RELEVANCE

This standardization is recommended to study initial oral biofilms aged up to 24 h to maximize the outcome of experiments and lead to better comparability of studies.

A Study on the Contributions of Sonication to the Identification of Bacteria Associated with Intubation Cannula Biofilm and the Risk of Ventilator-Associated Pneumonia

Ventilator-associated pneumonia is one of the most severe complications of critically ill patients that need mechanical respiratory support, as it poses a significant risk of prolonging hospitalization, disability, and even death. This is why physicians worldwide target newer methods for prevention, early diagnosis, and early target treatment for this condition. There are few methods for a quick etiological diagnosis of pneumonia, especially point of care, and most are only readily available in some intensive care units. This is why a new, simple, and cheap method is needed for determining the bacteria that might be infectious in a particular patient. The manner in question is sonication. Method: In this prospective, observational, single-center study, endotracheal cannula specimens will be collected from at least 100 patients in our intensive care unit. This specimen will be submitted to a specific sonication protocol for bacteria to dislodge the biofilm inside the cannula. The resulting liquid will be seeded on growth media, and then a comparison will be made between the germs in the biofilm and the ones in the tracheal secretion of the patient. The primary purpose is to determine the bacteria before the appearance of a manifest infection.

Visible Light-Responsive Selenium Nanoparticles Combined with Sonodynamic Therapy to Promote Wound Healing

In this paper, we synthesized selenium nanoparticles (SeNPs) that could be effectively excited by pure yellow light (YL) source to enhance antibacterial ability. Meanwhile, YL could also play the role of anti-inflammatory and promote wound healing. In addition, in order to overcome the problem of low penetration depth of photodynamic therapy (PDT), SeNPs were encapsulated with polyethylenimine (PEI), then modified with the sound sensitive agent indocyanine green (ICG), realizing the combined photoacoustic therapy to promote the healing of wounds infected by drug-resistant bacteria. The antibacterial efficiency of methicillin-resistant Staphylococcus aureus (MRSA) and Escherichia coli (E. coli) reached more than 99% in in vitro and in vivo experiments within 10 min, which could safely and quickly kill drug-resistant bacteria to repair and heal wounds.

Recent trends in the applications of sonochemical reactors as an advanced oxidation process for the remediation of microbial hazards associated with water and wastewater: A critical review

Water is one of the major sources that spread human diseases through contamination with bacteria and other pathogenic microorganisms. This review focuses on microbial hazards as they are often present in water and wastewater and cause various human diseases. Among the currently used disinfection methods, sonochemical reactors (SCRs) that produce free radicals combined with advanced oxidation processes (AOPs) have received significant attention from the scientific community. Also, this review discussed various types of cavitation reactors, such as acoustic cavitation reactors (ACRs) utilizing ultrasonic energy (UE), which had been widely employed, involving AOPs for treating contaminated waters. Besides ACRs, hydrodynamic cavitation reactors (HCRs) also effectively destroy and deactivate microorganisms to varying degrees. Cavitation is the fundamental phenomenon responsible for initiating many sonochemical reactions in liquids. Bacterial degradation occurs mainly due to the thinning of microbial membranes, local warming, and the generation of free radicals due to cavitation. Over the years, although extensive investigations have focused on the antimicrobial effects of UE (ultrasonic energy), the primary mechanism underlying the cavitation effects in the disinfection process, inactivation of microbes, and chemical reactions involved are still poorly understood. Therefore, studies under different conditions often lead to inconsistent results. This review investigates and compares other mechanisms and performances from greener and environmentally friendly sonochemical techniques to the remediation of microbial hazards associated with water and wastewater. Finally, the energy aspects, challenges, and recommendations for future perspectives have been provided.

Physical Approaches to Prevent and Treat Bacterial Biofilm

Prosthetic joint infection (PJI) presents several clinical challenges. This is in large part due to the formation of biofilm which can make infection eradication exceedingly difficult. Following an extensive literature search, this review surveys a variety of non-pharmacological methods of preventing and/or treating biofilm within the body and how they could be utilized in the treatment of PJI. Special attention has been paid to physical strategies such as heat, light, sound, and electromagnetic energy, and their uses in biofilm treatment. Though these methods are still under study, they offer a potential means to reduce the morbidity and financial burden related to multiple stage revisions and prolonged systemic antibiotic courses that make up the current gold standard in PJI treatment. Given that these options are still in the early stages of development and offer their own strengths and weaknesses, this review offers an assessment of each method, the progress made on each, and allows for comparison of methods with discussion of future challenges to their implementation in a clinical setting.

Invariant in variants

The coronavirus Covid-19 mutates quickly in the pandemic, leaves people struggling to verify and improve the effectiveness of the vaccine based on biochemistry. Is there any physical invariant in the variants of such kind of pathogen that could be taken advantage to ease the tensions? To this point, extensive numerical experiments based on continuity mechanics have been accomplished to discover the consistent vibration modes and the range of natural frequency of coronavirus Covid-19. Such invariant could help us in developing some flexible technique to deactivate the coronavirus, like as resonantly breaking the viral spike by ultrasound wave. The fundamental mechanisms governing such process are demonstrated via solving the coupled acoustic wave and elastic dynamic equations, after which the practical strategies are proposed to efficiently realize the technique concept.

Ultrasonic cleaning is effective in removing carbonized clots and tissue from the insulation‐tipped diathermic knife‐2

Objectives

Since carbonized clots and tissue (debris) tend to adhere firmly to the tip of the endoscopic submucosal dissection (ESD) knife as the procedure proceeds, manual removing the firm debris is often challenging and time‐consuming. Recently, effective ultrasonic cleaning for other medical devices has been reported. The aim of the present study was to clarify whether ultrasonic cleaning is effective in removing the debris on the insulation‐tipped diathermic (IT) knife‐2.

Methods

This study was an ex‐vivo experimental randomized study. A total of 40 IT knife‐2 knives with debris on their tip surfaces were prepared and randomly assigned to two groups (Group A and Group B). The knives in Group A were cleaned using the conventional scrubbing method for 30 s (conventional cleaning method), while those in Group B were cleaned using a combined method of scrubbing for 20 s and ultrasonic cleaning for 10 s (combined ultrasonic cleaning method). The tip electrode of the knife after cleaning was photographed under a microscope (40x). The 40 images of the knives were evaluated by independent three endoscopists and two clinical engineers using the five‐step evaluation criteria ranging from cleaning score 1 (dirty) to 5 (clean).

Results

The mean cleaning score of 3.78 (range: 2.33–4.67) in Group B was significantly higher than that of 1.68 (range: 1.00–2.83) in Group A.

Conclusions

The combined ultrasonic cleaning method could remove debris adhering to the IT knife‐2 more effectively than the conventional cleaning method. Ultrasonic cleaning may be applied for real‐world ESD.

Enhanced antimicrobial activity through the combination of antimicrobial photodynamic therapy and low-frequency ultrasonic irradiation

The rapid increase of antibiotic resistance in pathogenic microorganisms has become one of the most severe threats to human health. Antimicrobial photodynamic therapy (aPDT), a light-based regimen, has offered a compelling nonpharmacological alternative to conventional antibiotics. The activity of aPDT is based on cytotoxic effect of reactive oxygen species (ROS), which are generated through the photosensitized reaction between photon, oxygen and photosensitizer. However, limited by the penetration of light and photosensitizers in human tissues and/or the infiltration of oxygen and photosensitizers in biofilms, the eradication of deeply located or biofilm-associated infections by aPDT remains challenging. Ultrasound irradiation bears a deeper penetration in human tissues than light and, sequentially, can promote drug delivery through cavitation effect. As such, the combination of ultrasound and aPDT represents a potent antimicrobial strategy. In this review, we summarized the recent progresses in the area of the combination therapy using ultrasound and aPDT, and discussed the potential mechanisms underlying enhanced antimicrobial effect by this combination therapy. The future research directions are also highlighted.

Viability, Sublethal Injury, and Release of Cellular Components From Alicyclobacillus acidoterrestris Spores and Cells After the Application of Physical Treatments, Natural Extracts, or Their Components

Alicyclobacillus acidoterrestris is a spoiling microorganism regarded as one of the most important causes of spoilage of fruit juices and acidic products. In this paper, four strains of A. acidoterrestris (type strain-DSM 3922; two wild strains isolated from soil-C8 and C24; wild strain isolated from a spoiled pear juice CB1) were treated through natural extracts/active compounds from essential oils (EOs), and physical treatments were used to assess their susceptibility and the presence of sublethal injury. The characterization of damage was also performed. The results suggest that it is possible to control A. acidoterrestris through alternative approaches, although the effect relied upon the age of spores. In addition to the mere antimicrobial effect, some treatments could cause a sublethal injury on spores. Lemon extract was the most effective treatment for both the antimicrobial effect and the sublethal injury, as evidenced by the release of proteins, and calcium dipicolinate [dipicolinic acid (DPA)] by fresh spores and only DPA (with an exception for C8) by old spores. A sublethal injury with protein release was also found for physical treatments [US (ultrasound) or heating]. For the first time, this paper reports on the existence of a sublethal injury for A. acidoterrestris, and this evidence could also be a challenge, because injured microorganisms could restore their metabolism, or an opportunity to design new preserving treatments.

Biofilm Management in Wound Care

LEARNING OBJECTIVES

After studying this article, the participant should be able to: 1. Understand the basics of biofilm infection and be able to distinguish between planktonic and biofilm modes of growth. 2. Have a working knowledge of conventional and emerging antibiofilm therapies and their modes of action as they pertain to wound care. 3. Understand the challenges associated with testing and marketing antibiofilm strategies and the context within which these strategies may have effective value.

SUMMARY

The Centers for Disease Control and Prevention estimate for human infectious diseases caused by bacteria with a biofilm phenotype is 65 percent and the National Institutes of Health estimate is closer to 80 percent. Biofilms are hostile microbial aggregates because, within their polymeric matrix cocoons, they are protected from antimicrobial therapy and attack from host defenses. Biofilm-infected wounds, even when closed, show functional deficits such as deficient extracellular matrix and impaired barrier function, which are likely to cause wound recidivism. The management of invasive wound infection often includes systemic antimicrobial therapy in combination with débridement of wounds to a healthy tissue bed as determined by the surgeon who has no way of visualizing the biofilm. The exceedingly high incidence of false-negative cultures for bacteria in a biofilm state leads to missed diagnoses of wound infection. The use of topical and parenteral antimicrobial therapy without wound débridement have had limited impact on decreasing biofilm infection, which remains a major problem in wound care. Current claims to manage wound biofilm infection rest on limited early-stage data. In most cases, such data originate from limited experimental systems that lack host immune defense. In making decisions on the choice of commercial products to manage wound biofilm infection, it is important to critically appreciate the mechanism of action and significance of the relevant experimental system. In this work, the authors critically review different categories of antibiofilm products, with emphasis on their strengths and limitations as evident from the published literature.

Control Measures of Pathogenic Microorganisms and Shelf-Life Extension of Fresh-Cut Vegetables

We investigated the combined effect of using slightly acidic electrolyzed water (SAEW), ultrasounds (US), and ultraviolet-C light-emitting diodes (UV-C LED; 275 nm) for decreasing pathogenic Escherichia coli and Staphylococcus aureus (SEA) in fresh-cut vegetables, including carrots, celery, paprika, and cabbage. Survival of pathogenic E. coli and SEA and quality properties of fresh-cut vegetables at 5 and 15 °C for 7 days were also investigated. When combined treatment (SAEW + US + UV-C LED) was applied to fresh-cut vegetables for 3 min, its microbial reduction effect was significantly higher (0.97~2.17 log CFU/g) than a single treatment (p < 0.05). Overall, the reduction effect was more significant for SEA than for pathogenic E. coli. At 5 °C, SAEW + US and SAEW + US + UV-C LED treatments reduced populations of pathogenic E. coli and SEA in all vegetables. At 15 °C, SAEW + US + UV-C LED treatment inhibited the growth of both pathogens in carrot and celery and extended the shelf life of fresh-cut vegetables by preventing color changes in all vegetables. Although the effects of treatments varied depending on the characteristics of the vegetables and pathogens, UV-C LED can be suggested as a new hurdle technology in fresh-cut vegetable industry.

A Review on Sonochemistry and Its Environmental Applications

Sonochemistry is a significant contributor to green science as it includes: (i) the use of less toxic compounds and environmentally safe solvents, (ii) improvement of reaction conditions and selectivity, (iii) no toxic sludge generation, (iv) reduction in the energy use for chemical transformations, (v) reusability of materials. In water and wastewater treatment, ultrasound is used as an advanced oxidation process to eliminate refractory pollutants. Ultrasound is also used as a very effective sludge pretreatment technology in wastewater treatment plants to facilitate biogas production. Moreover, sonochemical synthesis of nanoparticles has recently attracted great attention as a greener protocol. This paper presents the main applications of ultrasound in environmental remediation and protection. The study also introduces mechanism for the degradation of pollutants from water via sonication in aqueous media and the principle factors affecting the cavitational effect.

Microbiological properties of poultry breast meat treated with high-intensity ultrasound

Lactic acid, psychrophilic, and mesophilic bacteria, Escherichia coli, Salmonella spp. and Staphylococcus aureus were enumerated on chicken breasts after treatment with different high intensity ultrasound (frequency 40 kHz, intensity 9.6 W/cm^-2) application times (0, 30, and 50 min) and packaging atmospheres (aerobic and vacuum) after a 7-day storage. The experiment was performed in commercial 7-week-old chicken breasts. Counts were performed prior to and immediately after ultrasonication, and on the 7th day of chill-storage. After sonication and storage, mesophiles, psychrophiles, LAB and S. aureus increased statistically. Psychrophiles decreased significantly under anaerobic packaging. There were no differences among ultrasonication times in terms of mesophiles, psychrophiles, LAB, E. coli and Salmonella spp. S. aureus numbers had a significant reduction after 50 min sonication. Under these experimental conditions, high-intensity ultrasound for 50 min is a control method of S. aureus and the anaerobic packaging reduces numbers of psychrophiles in chicken breast. The effect of ultrasound is only significant after the storage time.

Organic-solvent-free extraction of carotenoids from yeast Rhodotorula glutinis by application of ultrasound under pressure

The extraction of Rhodotorula glutinis carotenoids by ultrasound under pressure (manosonication) in an aqueous medium has been demonstrated. The influence of treatment time, pressure, and ultrasound amplitude on R. glutinis inactivation and on the extraction of carotenoids was evaluated, and the obtained data were described mathematically. The extraction yields were lineal functions of those three parameters, whereas inactivation responded to a more complex equation. Under optimum treatment conditions, 82% of carotenoid content was recovered. Extraction of carotenoids in an aqueous medium was attributed to the capacity of ultrasound for cell disruption and emulsification. Cavitation caused the rupture of cell envelopes and the subsequent formation of small droplets of carotenoids surrounded by the phospholipids of the cytoplasmic membrane that would stabilize the emulsion. Analysis of the dispersed particle size of the extracts demonstrated that a fine, homogeneous emulsion was formed after treatment (average size: 230 nm; polydispersity <0.22). This research describes an innovative green process for extracting carotenoids from fresh biomass of R. glutinis in which only two unit operations are required: ultrasonic treatment, followed by a centrifugation step to discard cell debris. The extract obtained thanks to this procedure is rich in carotenoids (25 mg/L) and could be directly incorporated as a pigment in foods, beverages, and diet supplements; it can also be utilized as an ingredient in drugs or cosmetics.

Effects of ultrasonic treatment on the ammonia-oxidizing bacterial (AOB) growth kinetics

Ultrasound has in the past few decades found applications in a variety of disciplines including chemistry, medicine, physics, and to a much less extent microbiology. Our previous studies found that ultrasonic treatment increases the activity of ammonia-oxidizing bacteria (AOB) while suppressing nitrite-oxidizing bacteria (NOB), resulting in beneficial effects in wastewater treatment. In this study, the kinetic and microbiological features of nitrifying microorganisms in activated sludge intermittently treated with ultrasound were investigated to gain an improved understanding of the mechanism involved in ultrasound-induced stimulation of AOB kinetics. The nitrifying microorganisms were initially enriched over 100 days in a laboratory sequential batch reactor (SBR). Ultrasonic treatment of the sludge was then applied with the treatment time in each 12 h SBR cycle progressively increased from 4 to 24 min. Application of the treatment for 21 days led to a doubled maximum specific ammonia oxidation rate, and also the enhanced dominance of known AOB Nitrosomonas genus in the biomass. This stimulatory effect is well described by a modified enzyme catalyzed reaction model, showing a good linear relationship between the natural logarithm value of μ_max,AOB and the applied ultrasonic energy density. This result suggests that ultrasonic treatment likely reduced the activation energy of key enzymes involved in ammonium oxidation.

Ultrasonic debridement management of lower extremity wounds: retrospective analysis of clinical outcomes and cost

Objective:

The aim of this study was to assess wound healing outcomes following direct, low-frequency, high-intensity, ultrasonic debridement as a surgical adjunct for non-healing lower extremity wounds.

Methods:

A retrospective review was conducted for patients undergoing lower extremity wound treatment with direct, low-frequency (22.5 kHz), high-intensity (~60 W/cm2) ultrasonic debridement between January 2010 and January 2016. Clinical outcomes were assessed up to 180-days post-ultrasonic debridement. Descriptive statistics, cost and univariate analysis were performed.

Results:

Overall, 82 wounds in 51 patients were included. Mean age was 57.0 years (range: 32–69), and average body mass index (BMI) was 30.8 kg/m². Patient comorbidities consisted of smoking (47%; n=24), hypertension (75%; n=38), diabetes (45%; n=23), and peripheral vascular disease (51%, n=26). Average wound age at initial presentation was 1013 days (range: 2–5475 days) with an average wound size of 9.0cm x 7.4cm. At 180-days post-debridement, 60% (n=49) of wounds had completely healed. Readmission (47%; n=24) and reoperation (45%; n=23) rates were characterised by the reason for readmission and reoperation respectively. Readmission for wound healing (70%, n=39) was primarily for further debridements (41%; n=16). Wound infection (30%; n=7) was the most common readmission for wound complications (30%; n=17). Reoperations primarily consisted of treatments for further wound healing 96% (n=51). Cost analysis showed a lower total treatment cost for patients with improved healing ($78,698), compared with non-improved wounds ($137,707).

Conclusion:

In a complex, heterogeneous cohort of chronic extremity wounds, the use of direct, low-frequency, high-intensity, ultrasonic debridement is a safe and reliable adjunctive therapy for the management of these wounds.

Achieving mainstream nitrogen removal via the nitrite pathway from real municipal wastewater using intermittent ultrasonic treatment

Achieving mainstream nitrogen removal via the nitrite pathway (NH₄⁺ → NO₂^- → N₂) is highly beneficial for energy neutral/positive wastewater treatment. Our previous batch assays revealed that ultrasonic treatment can suppress nitrite-oxidizing bacteria (NOB) while enhancing the activity of ammonia-oxidizing bacteria (AOB). Based on this concept, this study investigated the feasibility of applying ultrasonication to achieve the nitrite pathway in mainstream wastewater treatment. Two lab-scale sequencing batch reactors were set-up in parallel and fed with real municipal wastewater. With 100% of the sludge treated every 12 h at a treatment energy input of 0.066 kJ per mg mixed liquor suspended solids, the nitrite pathway was rapidly (within two weeks) established in the experimental reactor with stable effluent nitrite accumulation ratio (NO₂^-/(NO₂^- + NO₃^-)) of above 80% and significantly decreased NOB population. In comparison, the control reactor always possessed the conventional nitrification and denitrification pathway. Economic analysis indicated that energy consumption is too high for practical applications. However, this technology may be used in conjunction with other technologies, whereby this ultrasonic treatment can be used infrequently (e.g. once every few months) when the nitrite pathway becomes unstable.

Effect of ultrasonication and thermal and pressure treatments, individually and combined, on inactivation of Bacillus cereus spores

Bacillus cereus spores are a concern to the food industry due to their high resistance to processing and their ability to germinate to vegetative cells under suitable conditions. This research aimed to elucidate the mechanisms of Bacillus cereus spore inactivation under ultrasonication (US) combined with thermal (thermosonication, TS) treatments, with pressure (manosonication, MS) treatments, and with thermal and pressure (manothermosonication, MTS) treatments. Electronic microscopy, dipicolinic acid (DPA) release, and flow cytometric assessments were used to investigate the inactivation effect and understand the inactivation mechanisms. The sporicidal effects of the US and thermal treatment were slight, and the MS and TS also showed little inactivation effect. However, ultrasonication promoted the detachment of the exosporium, thereby reducing the spore's ability to adhere to a surface, while the thermal treatment induced a decrease in the electron density in the nucleoid of bacterium, which retained a relatively intact exosporium and coat. MS caused 92.54% DPA release, which might be due to triggering of the germinant receptors or releasing of ions and Ca²⁺-DPA. In addition, the morphological changes such as core hydration and cortex degradation were significant after treatment with MS. The release of DPA and the morphological changes were responsible for the reduction in thermal resistance. The MTS showed a remarkable inactivation effect of 3.12 log CFU/mL reductions after 30 min of treatment. It was the most effective treatment and exhibited a large fraction of damage. In addition, the MTS had a significant impact on the intracellular structure of the spores, with the coat destroyed and the cortex damaged. These results indicated that ultrasonication combined with thermal and pressure treatments had a significant sporicidal effect on Bacillus cereus spores and could be a promising green sterilization technology.

Ultrasound mediated accelerated Anti-influenza activity of Aloe vera

Aloe vera (AV) is popular and has been commercialized as a beauty product, laxative, herbal medicine, the antimicrobial activity of AV is proven. The antiviral activity of AV however, has not been well documented except for a handful reports. Till date extraction of AV compounds is popularized using organic solvents, since the active components are effectively extracted in methanol. In the current work, we have employed a 5 min ultrasound based extraction for the effective extraction of aloin and aloe-emodin compounds from AV in water. This rapid, one-pot extraction process resulted in enhanced extraction of flavonoids and phenolics and enrichment of the aloin and aloe-emodin moieties in the ulrasonicated water extracts. The extracts were tested for their anti-influenza activity and, the results showed that the ultrasound extraction enabled the water extracts to show excellent anti influenza activity comparable to that seen in the methanolic extracts. Compared to the methanolic extracts which showed high cytotoxicity, the water extracts showed zero cytotoxicity. Spectrophotometric scans of the extracts confirmed the enrichment of the aloin and aloe emodin peaks in the ultrasonicated extracts of AV, suggesting their handiwork behind the anti-influenza activity. The demonstrated technique if appropriately implicated, would lead to promising solutions in the pharmaceutical pursuit against influenza virus.

Quantitative analysis of Staphylococcus aureus in patients with chronic rhinosinusitis under continuous ultrasound treatment

BACKGROUND AND OBJECTIVES

Bacterial pathogens, in particular drug resistant strains, involved in chronic rhinosinusitis may result in treatment failure. Ultrasound waves are able to destroy bacterial population in sinus cavities and can recover patients.

MATERIALS AND METHODS

Twelve patients with chronic sinusitis and 10 healthy controls were treated by continuous ultrasound waves. Clinical specimens were collected before and after treatment. Serial diluted specimens were cultured on blood agar, chocolate and MacConkey agar plates for bacterial isolation. Bacterial DNA was extracted and used for Staphylococcus aureus detection using quantitative PCR.

RESULTS

S. aureus was the most isolated bacterium (10 patients), which was eradicated from 8 patients after treatment. Using phenotypic methods at the beginning, 3 out of 10 healthy individuals were found to be positive. From 11 positive patients for S. aureus identified by real time qPCR, 9 showed significant reduction after treatment. In the healthy group, S. aureus was detected in 4 samples using qPCR, but they were clean at the second sampling.

CONCLUSION

According to our phenotypic and molecular experiments, continuous ultrasound treatment effectively reduced the bacterial population in studied patients (p < 0.01). This was a hopeful basis for doing more studies with ultrasound therapy as a treatment option.

Diagnostic and Therapeutic Ultrasound on Venous and Arterial Ulcers: A Focused Review

GENERAL PURPOSE

To provide information about the use of ultrasound for diagnostic and therapeutic treatment of venous and arterial ulcers.

TARGET AUDIENCE

This continuing education activity is intended for physicians, physician assistants, nurse practitioners, and nurses with an interest in skin and wound care.

LEARNING OBJECTIVES/OUTCOMES

After completing this continuing education activity, you should be able to: ABSTRACT: To review the diagnostic and therapeutic use of ultrasound on venous and arterial ulcers.

METHODS

PubMed was searched for peer-reviewed articles using the search terms "ultrasound for venous ulcers" and "ultrasound for arterial ulcers." The search yielded 282 articles on ultrasound for venous ulcers and 455 articles for ultrasound on arterial ulcers. Data from 36 articles were selected and included after abstract review.

RESULTS

Ultrasound is an established diagnostic modality for venous and arterial disease and is indicated for wound debridement. Recent evidence continues to support its superiority over standard of care in healing venous ulcers, but findings conflict in terms of the effectiveness of low-frequency ultrasound over high-frequency ultrasound. There are currently no standardized treatment protocols for ultrasound.

CONCLUSIONS

Diagnostic ultrasound is used to assess venous and arterial disease and guide appropriate treatment for ulcers. Therapeutic low-frequency ultrasound is used to debride the wound bed, as an adjunctive topical wound treatment with standard of care, and to guide the application of other advanced therapies to chronic wounds. Better trial designs and consistent data are needed to support the effectiveness of ultrasound therapy on venous and arterial ulcers.

Inactivation of Planktonic Escherichia coli by Focused 1-MHz Ultrasound Pulses with Shocks: Efficacy and Kinetics Upon Volume Scale-Up

This study addresses inactivation of E. coli in either 5- or 10-mL volumes, which were 50- to 100-fold greater than used in an earlier study (Brayman et al. 2017). Cells were treated with 1-MHz pulsed high-intensity focused ultrasound (10 cycles, 2-kHz repetition frequency, +65/-12.8 MPa focal pressures). The surviving fraction was assessed by coliform assay, and inactivation demonstrated curvilinear kinetics. The reduction of surviving fraction to 50% required 2.5 or 6 min in 5- or 10-mL samples, respectively. Exposure of 5 mL for 20 min reduced the surviving fraction to ∼1%; a similar exposure of 10-mL samples reduced the surviving fraction to ∼10%. Surviving cells from 5-min exposures appeared normal under light microscopy, with minimal debris; after 20 min, debris dominated. Transmission electron microscopy images of insonated samples showed some undamaged cells, a few damaged but largely intact cells and comminuted debris. Cellular damage associated with substantive but incomplete levels of inactivation can be variable, ranging from membrane holes tens of nanometers in diameter to nearly complete comminution.

[Research progress of chronic wound debridement]

Objective

To review the research progress of chronic wound debridement.

Methods

The recent related literature concerning the mechanisms, advantages, limitations, and indications of the technologies of chronic wound debridement was extensively consulted, reviewed, and summarized.

Results

Debridement is essential for chronic wound healing, which includes autolytic debridement, enzymatic debridement, biodebridement, mechanical debridement, sharp/surgical debridement, ultrasound debridement, hydrosurgery debridement, and coblation debridement. Each technique has its own advantages and disadvantages.

Conclusion

There are many types of technologies of chronic wound debridement, which can be chosen according to clinical conditions. It is showed there are more significant advantages associated with the technique of coblation debridement relatively, which also has greater potential. Further study is needed to improve its efficacy.

What Is the Role of Diagnostic and Therapeutic Sonication in Periprosthetic Joint Infections?

BACKGROUND

Periprosthetic joint infection (PJI) is one of the most dreaded complications in joint replacement surgery. Diagnosis and treatment can be difficult and biofilms are of major concern due to their low susceptibility toward antibiotics.

METHODS

This review focuses on the use of sonication as an evolving diagnostic and adjunct treatment modality in the context of PJI. Therapeutic application of sonication is discussed separately for its (i) direct action on bacteria, (ii) synergistic effects with antibiotics, and (iii) effects on release of antibiotics from bone cement.

RESULTS

Used as a diagnostic tool, sonication shows promising results with respect to sensitivity and specificity when compared to conventional methods, notably after previous administration of antibiotics. As an adjunct treatment modality, the chemical, physical, and mechanical effects of sonication are primarily driven by cavitation and recognized as the main cause for bactericidal effects but the exact underlying mechanisms have not been identified yet. Sonication alone does not have the ability to completely eradicate biofilms but synergistic effects when used in conjunction with antibiotics have been reported. There is also evidence for enhanced antibiotic release from bone cement.

CONCLUSION

Sonication is as an evolving modality in the context of PJIs. As a diagnostic tool, it has not been introduced in routine clinical practice and sonication as a treatment modality in PJIs is still in an experimental stage. Factors such as frequency, pressure, chemical activity, intensity, and exposure time need to be evaluated for optimal application of sonication and may also improve study comparison.

Antifungal photodynamic inactivation against dermatophyte Trichophyton rubrum using nanoparticle-based hybrid photosensitizers

Trichophyton rubrum is one of the most common dermatophytes, which can cause fungal nail and ringworm infections. Infections associated with T. rubrum have become a global phenomenon. Herein, we report the antifungal photodynamic inactivation of T. rubrum (ATCC 28188) using the mesoporous silica-coated silver nanoparticle-based hybrid photosensitizers without involving antifungal drugs. Results show that the hybrid photosensitizers display low cytotoxicity under the experimental conditions where significant killing (∼3 orders of magnitude) against T. rubrum is observed. These results demonstrate the potential applications of the nanoparticle-based hybrid photosensitizers in antifungal photodynamic therapy against T. rubrum.

Microbial Quality and Shelf Life of Blueberry Purée Developed Using Cavitation Technology

Blueberry purée was developed using hydrodynamic cavitation technology. The product was made from entire blueberries without adding any food additives. In this study, microbial reduction following each processing stage (at the industry setting) and after product pasteurization at 86, 88, 90, 92, 94, and 96 °C was investigated. Microbial quality including total plate counts, yeast and molds, and heat-resistant molds counts was determined. Shelf life of pasteurized products stored for up to 24 weeks at room temperature were assessed for microbial quality, soluble solids (°Brix), titratable acidity (citric acid %), pH, viscosity (cP) and flow rate (cm/30 s). Our results indicated that heat-resistant molds, initially present in frozen blueberries with counts at 2.03 log CFU/200g, were totally inactivated at 94 to 96 °C with 1 to 2 min holding time. Shelf life study showed that no product spoilage was caused by bacteria, yeasts and heat-resistant molds along with non-significant changes of textural characteristics. This study provided useful information for the food industry to develop variety of fruit purée products with no wastes of fruit materials.

PRACTICAL APPLICATION

This study provides useful information for the food industry to develop safe liquid food products using cavitation technology without wasting any raw materials.

Inactivation of filter bound aerosolized MS2 bacteriophages using a non-conductive ultrasound transducer

The inactivation of viruses that retain their infectivity when transmitted through the air is challenging. To address this issue, this study used a non-contact ultrasound transducer (NCUT) to generate shock waves in the air at specific distances, input voltages, and exposure durations, targeting bacteriophage virus aerosols captured on to H14 HEPA filters. Initially, a frequency of 27.56 kHz (50V) at 25-mm distance was used, which yielded an inactivation efficiency of up to 32.69 ± 12.10%. Other frequencies at shorter distances were investigated, where 29.10 kHz had the highest inactivation efficiency (up to 81.95 ± 9.79% at 8.5-mm distance and 100 V). Longer exposure times also influenced virus inactivation, but the results were inconclusive because the NCUT overheated with time. Overall, NCUT appears to be a promising method for inactivating virus aerosols that may be safer than other forms of inactivation, which can cause genetic mutations or produce dangerous by-products.

Effect of ultra-sonication and its use with sodium hypochlorite as antifouling method against Mytilus edulis larvae and mussel

Biofouling is a stubborn problem in cooling systems where using raw water from lakes, rivers, and sea. The effect of ultrasound and its sequential application with sodium hypochlorite (chlorination) upon marine bivalve Mytilus edulis (blue mussel), a massive fouling organism, has been studied and discussed here. The results obtained from the work carried out have shown that 42 kHz ultrasound is better than 28 kHz in accordance with veliger larvae mortality. The 42 kHz ultrasound has enhanced the mortality rate of veliger larvae than only free-residual chlorination up to 99%. On the other side, the 14-mm size mussel was less resistance than 25-mm size mussel to 42 kHz ultrasonication, among the studied two sizes (14 and 25 mm) of the blue mussel. Lethal time (100%) have decreased by 1-12% used for the sequential action of 42 kHz ultrasonic followed by free-residual chlorination compare with only free-residual chlorination treatment. The obtained results are put forward that the application of ultra-sonication before chlorination can reduce the mussel extinct time up to 12%. Obviously, this result will provide a possible use of ultra-sonication with famous chlorination antifouling treatment and eventually can decrease the chlorine exposure time and dose. It could discharge low chlorine by-products that may provide an environment friendly way.

Efficient inactivation of MS-2 virus in water by hydrodynamic cavitation

The aim of this study was to accurately quantify the impact of hydrodynamic cavitation on the infectivity of bacteriophage MS2, a norovirus surrogate, and to develop a small scale reactor for testing the effect of hydrodynamic cavitation on human enteric viruses, which cannot be easily prepared in large quantities. For this purpose, 3 mL scale and 1 L scale reactors were constructed and tested. Both devices were efficient in generating hydrodynamic cavitation and in reducing the infectivity of MS2 virus. Furthermore, they reached more than 4 logs reductions of viral infectivity, thus confirming the scalability of hydrodynamic cavitation for this particular application. As for the mechanism of page inactivation, we suspect that cavitation generated OH^- radicals formed an advanced oxidation process, which could have damaged the host's recognition receptors located on the surface of the bacteriophage. Additional damage could arise from the high shear forces inside the cavity. Moreover, the effectiveness of the cavitation was higher for suspensions containing low initial viral titers that are in similar concentration to the ones found in real water samples. According to this, cavitation generators could prove to be a useful tool for treating virus-contaminated wastewaters in the future.

Inactivation of Planktonic Escherichia coli by Focused 2-MHz Ultrasound

This study was motivated by the desire to develop a non-invasive means to treat abscesses, and represents the first steps toward that goal. Non-thermal, high-intensity focused ultrasound (HIFU) was used to inactivate Escherichia coli (∼1 × 10⁹ cells/mL) in suspension. Cells were treated in 96-well culture plate wells using 1.95-MHz ultrasound and incident focal acoustic pressures as high as 16 MPa peak positive and 9.9 MPa peak negative (free field measurements). The surviving fraction was assessed by coliform culture and the alamarBlue assay. No biologically significant heating was associated with ultrasound exposure. Bacterial inactivation kinetics were well described by a half-life model, with a half-time of 1.2 min. At the highest exposure levels, a 2log inactivation was typically achieved within 10 min. The free field-equivalent peak negative acoustic pressure threshold for inactivation was ∼7 MPa. At the highest acoustic pressures used, inactivation efficacy was insensitive to reciprocal changes in pulse length and pulse repetition frequency at constant duty factor. Although treated volumes were very small, proof of principle was provided by these experiments.

Low-Frequency Ultrasound Debridement in Chronic Wound Healing: A Systematic Review of Current Evidence

Chronic wounds are painful and debilitating to patients, pose a clinical challenge to physicians, and impose financial burden on the health-care system. New treatment options are therefore highly sought after. Ultrasound debridement is a promising technology that functions to disperse bacterial biofilms and stimulate wound healing. In this review, we focus on low-frequency ultrasound (20-60 kHz) and summarize the findings of 25 recent studies examining ultrasound efficacy. Ultrasound debridement appears to be most effective when used 3 times a week and has the potential to decrease exudate and slough, decrease patient pain, disperse biofilms, and increase healing in wounds of various etiology. Although current studies are generally of smaller size, the results are promising and we recommend the testing of low-frequency ultrasound therapy in clinical practice on a larger scale.

Ultrasonic Treatment Enhanced Ammonia-Oxidizing Bacterial (AOB) Activity for Nitritation Process

Oxidation of ammonia to nitrite rather than nitrate is critical for nitritation process for wastewater treatment. We proposed a promising approach by using controlled ultrasonic treatment to enhance the activity of ammonia-oxidizing bacteria (AOB) and suppress that of nitrite-oxidizing bacteria (NOB). Batch activity assays indicated that when ultrasound was applied, AOB activity reached a peak level and then declined but NOB activity deteriorated continuously as the power intensity of ultrasound increased. Kinetic analysis of relative microbial activity versus ultrasonic energy density was performed to investigate the effect of operational factors (power, sludge concentration, and aeration) on AOB and NOB activities and the test parameters were selected for reactor tests. Laboratory sequential batch reactor (SBR) was further used to test the ultrasonic stimulus with 8 h per day operational cycle and synthetic waste urine as influent. With specific ultrasonic energy density of 0.09 kJ/mg VSS and continuously fed influent containing above 200 mg NH3-N/L, high AOB reproductive activity was achieved and nearly complete conversion of ammonia-N to nitrite was maintained. Microbial structure analysis confirmed that the treatment changed community of AOB, NOB, and heterotrophs. Known AOB Nitrosomonas genus remained at similar level in the biomass while typical NOB Nitrospira genus disappeared in the SBR under ultrasonic treatment and after the treatment was off for 30 days.

Evaluation of Ultrasound-Induced Damage to Escherichia coli and Staphylococcus aureus by Flow Cytometry and Transmission Electron Microscopy

As a nonthermal sterilization technique, ultrasound has attracted great interest in the field of food preservation. In this study, flow cytometry and transmission electron microscopy were employed to investigate ultrasound-induced damage to Escherichia coli and Staphylococcus aureus. For flow cytometry studies, single staining with propidium iodide (PI) or carboxyfluorescein diacetate (cFDA) revealed that ultrasound treatment caused cell death by compromising membrane integrity, inactivating intracellular esterases, and inhibiting metabolic performance. The results showed that ultrasound damage was independent of initial bacterial concentrations, while the mechanism of cellular damage differed according to the bacterial species. For the Gram-negative bacterium E. coli, ultrasound worked first on the outer membrane rather than the cytoplasmic membrane. Based on the double-staining results, we inferred that ultrasound treatment might be an all-or-nothing process: cells ruptured and disintegrated by ultrasound cannot be revived, which can be considered an advantage of ultrasound over other nonthermal techniques. Transmission electron microscopy studies revealed that the mechanism of ultrasound-induced damage was multitarget inactivation, involving the cell wall, cytoplasmic membrane, and inner structure. Understanding of the irreversible antibacterial action of ultrasound has great significance for its further utilization in the food industry.