Efficacy of citric acid and sodium hypochlorite as disinfectants against Mycoplasma bovis

Chemical Characterization and Effect of a Lactobacilli-Postbiotic on Streptococcus mutans Biofilm In Vitro

Postbiotic is the term used to define the soluble factors, metabolic products, or byproducts released by live probiotic bacteria or after its lysis. The objective of this study was to carry out the chemical characterization of the postbiotic of Lacticaseibacillus rhamnosus LR-32 and to evaluate its in vitro effect on the development of the Streptococcus mutans biofilm. After the cultivation of the probiotic strain, the postbiotic was extracted by centrifuging the culture and filtering the supernatant. This postbiotic was characterized by using gas chromatography coupled with mass spectrometry (GC-MS), and then it was used to determine the growth inhibition of S. mutans in its planktonic form; additionally, its effects on the following parameters in 48 h biofilm were evaluated: viable bacteria, dry weight, and gene expression of glucosyltransferases and VicR gene. The control group consisted of the biofilm without any treatment. A paired t-test was performed for statistical analysis, with the p-value set at 5%. Seventeen compounds of various chemical classes were identified in the postbiotic, including sugars, amino acids, vitamins, and acids. The treatment with the postbiotic led to an inhibition of the growth of S. mutans in its planktonic form, as well as a decrease in the number of viable bacteria, reduction in dry weight, and a negative regulation of the gene expression of gtfB, gtfC, gtfD, and vicR in its biofilm state, compared with the nontreated group (p < 0.05). The postbiotic of L. rhamnosus impaired the development of S. mutans biofilm.

Obg plays a significant role in temperature sensitivity of Mycoplasma synoviae live attenuated vaccine strain MS-H

The MS-H vaccine strain (Vaxsafe MS®; Bioproperties Pty. Ltd., Australia) is a live attenuated temperature sensitive derivative of a virulent strain of M. synoviae, 86079/7NS, and is used to prevent diseases from M. synoviae challenges in poultry farms. The genome sequence of MS-H includes 32 single nucleotide polymorphisms (SNPs) compared to that of 86079/7NS. To investigate the nature of mutations responsible for temperature sensitivity, MS-H strain was subjected to thermal adaptation in vitro and in vivo. The only observed variation detected in the MS-H culture following sequential passages with incremental incubation temperature from 33 °C to 39.5 °C was an Ala210Val variation in Obg protein, associated with loss of temperature sensitivity phenotype. An identical variation was detected in the MS-H culture reisolated from one out of five bird 28 days after inoculation with MS-H. These findings suggest that M. synoviae is capable of thermoadaptive evolution and Obg plays a significant role in this trait.

Assessment of acute inhalation toxicity of citric acid and sodium hypochlorite in rats

BACKGROUND

Citric acid (CA) and sodium hypochlorite (NaOCl) have been used to disinfect animals to protect them against avian influenza and foot-and-mouth disease.

OBJECTIVES

We performed a good laboratory practice (GLP)-compliant animal toxicity study to assess the acute toxic effects of CA and NaOCl aerosol exposure in Sprague-Dawley rats.

METHODS

Groups of five rats per sex were exposed for 4 h to four concentrations of the two chemicals, i.e., 0.00, 0.22, 0.67, and 2.00 mg/L, using a nose-only exposure. After a single exposure to the chemicals, clinical signs, body weight, and mortality was observed during the observation period. On day 15, an autopsy, and then gross findings, and histopathological analysis were performed.

RESULTS

After exposure to CA and NaOCl, body weight loss was observed but recovered. Two males died in the CA 2.00 mg/L group and, two males and one female died in the 2.00 mg/L NaOCl group. In the gross findings and histopathological analysis, discoloration of the lungs was observed in the CA exposed group and inflammatory lesions with discoloration of the lungs were observed in the NaOCl exposed group. These results suggest that the lethal concentration 50 (LC50) of CA is 1.73390 mg/L for males and > 1.70 mg/L for females. For NaOCl, the LC50 was 2.22222 mg/L for males and 2.39456 mg/L for females.

CONCLUSIONS

The Globally Harmonized System is category 4 for both CA and NaOCl. In this study, the LC50 results were obtained through a GLP-based acute inhalation toxicity assessment. These results provide useful data to reset safety standards for CA and NaOCl use.

Synthesis, determination, and bio-application in cellular and biomass-bamboo imaging of natural cinnamaldehyde derivatives

Cinnamon essential oil (CEO) is the main ingredient in the renewable biomass of cinnamon, which contains natural cinnamaldehyde. To valorize the value of cinnamaldehyde, two simple and useful compounds (1 and 2) from CEO were synthesized using a Schiff-base reaction and characterized by infrared spectra (IR), nuclear magnetic resonance (NMR), and high-resolution mass spectrometry (HRMS). Compound 1 was used to confirm the presence of Fe³⁺ and ClO⁻ in solution, as well as compound 2. Using fluorescence enhancement phenomena, it offered practicable linear relationship of 1’s fluorescence intensity and Fe³⁺ concentrations: (0–8.0 × 10⁻⁵ mol/L), y = 36.232x + 45.054, R² = 0.9947, with a limit of detection (LOD) of 0.323 μM, as well as compound 2. With increasing fluorescence, F₄₀₄/F₄₂₆ of 1 and the ClO⁻ concentration (0–1.0 × 10⁻⁴ mol/L) also had a linear relationship: y = 0.0392x + 0.5545, R² = 0.9931, LOD = 0.165 μM. However, the fluorescence intensity of 2 (596 nm) was quenched by a reduced concentration of ClO⁻, resulting in a linear. In addition, compounds 1 and 2 were used to image human astrocytoma MG (U-251), brain neuroblastoma (LN-229) cells, and bamboo tissue by adding Fe³⁺ or ClO⁻, with clear intracellular fluorescence. Thus, the two compounds based on CEO could be used to dye cells and bamboo tissues by fluorescence technology.

Rational development and evaluation of novel formulations for urinary health

OBJECTIVE

Urinary tract infections (UTI) among women form a substantial part of medical practice and both patients and medical professionals have an interest in non-antibiotic treatments and preventative measures. This research provides preliminary data on a multi-functional composition, DAPAD, which explored several biologic activities of relevance to UTI.

STUDY DESIGN

This formulation included D-mannose, citric acid, three prebiotic compounds, and extracts of dandelion and astragalus. Studies performed employed 4 bacterial strains that have relevance to UTI including E. coli, Proteus mirabilis, Streptococcus agalactiae and Enterococcus faecalis.

RESULTS

Key findings from in vitro studies included: DAPAD at full- and half-strength inhibited growth of all UTI bacteria. Evidence for D-mannose agglutination of E. coli was demonstrated. D-mannose also showed unexpected effects on bacterial membrane integrity with vital staining and modest growth restriction. We did not demonstrate growth inhibition by dandelion or astragalus extracts but the latter showed diminished cytokine elaboration by bladder epithelial cells.

CONCLUSION

DAPAD is a multifunctional composition that may warrant further development as a UTI treatment or preventive if supported by clinical evaluation.

Synthesis, optical properties, determination and imaging in living cells and bamboo of cinnamaldehyde derivatives

Two Schiff-base fluorescent probes (1 and 2) were directly synthesized from natural cinnamaldehyde, and they were characterized by FT-IR, ¹H and ¹³C NMR, HRMS. Compound 1 had no fluorescence, while compound 2 could emit significant yellow fluorescence in solid and provide green light in solution. Probe 1 could selectively sense ClO^- with a fluorescence enhancement, providing a good linear relationship between the fluoresence intensity and ClO^- concentrations (0-5.5 × 10^-5 mol/L), y = 175.64x-19.399, R² = 0.9937, and the limit of detection (LOD) was 39.4 nM. Probe 2 was sensitive for Cu²⁺ by quenching with two linear relationships at the Cu²⁺ concentrations from 0 to 2.1 × 10^-5 mol/L, LOD = 73.9 nM. Furthermore, live celluar imaging of human astrocytoma U-251 MG cells and human liver cancer cells (Hu-7) had achieved using the 1 + ClO^- and 2, offering clear intracellular fluorescence. Finally, the 1 + ClO^- and 2 could also be used to dye bamboo tissues for a good use. Thus, the cinnamaldehyde derivatives could be further used in the field of celluar and bamboo imaging.

Biocide Use in the Antimicrobial Era: A Review

Biocides are widely used in healthcare and industry to control infections and microbial contamination. Ineffectual disinfection of surfaces and inappropriate use of biocides can result in the survival of microorganisms such as bacteria and viruses on inanimate surfaces, often contributing to the transmission of infectious agents. Biocidal disinfectants employ varying modes of action to kill microorganisms, ranging from oxidization to solubilizing lipids. This review considers the main biocides used within healthcare and industry environments and highlights their modes of action, efficacy and relevance to disinfection of pathogenic bacteria. This information is vital for rational use and development of biocides in an era where microorganisms are becoming resistant to chemical antimicrobial agents.

Analysis of Commercial Hand Sanitisers amid CoViD-19: Are We Getting the Products that We Need?

The CoViD-19 pandemic has caused a sudden spike in demand and production of hand sanitisers. Concerns are rising regarding the quality of such products, as the safeguard of consumers is a priority worldwide. We analyse here the ethanolic content of seven off-the-shelf hand sanitiser gels (two biocides and five cosmetics) from the Italian market, using gas chromatography. The WHO recommends that products containing ethanol should have 60-95% (v/v) alcohol. Four of the tested hand gels have ethanolic contents within the recommended range, while three products (all cosmetics) contain < 60% (v/v), i.e. 52.1% (w/w), ethanol. The product with the lowest alcoholic content has 37.1% w/w ethanol. Toxic methanol is not found in any of the hand sanitisers. We show, in addition, that products with the highest ethanolic content have generally greater antibacterial activity. In conclusion, all tested products are complying with the EU regulations, as the three "substandard" products are classified as cosmetics, whose purpose is cleaning and not disinfecting. Nevertheless, if such hand cleaners were inappropriately used as hand disinfectants, they might be ineffective. Thus, consumer safety relays on awareness and ability to distinguish between biocidal and cosmetics hand gels. The obtained results might sensitise the scientific community, health agencies and ultimately consumers towards the risks of using hand sanitisers of substandard alcoholic concentration. If the wrong product is chosen by consumers, public health can be compromised by the inappropriate use of "low-dosed" cosmetic gels as disinfectants, particularly during the period of the CoViD-19 pandemic.

Mycoplasma bovis Infections-Occurrence, Diagnosis and Control

Mycoplasma bovis is a cause of bronchopneumonia, mastitis and arthritis but may also affect other main organs in cattle such us the eye, ear or brain. Despite its non-zoonotic character, M. bovis infections are responsible for substantial economic health and welfare problems worldwide. M. bovis has spread worldwide, including to countries for a long time considered free of the pathogen. Control of M. bovis infections is hampered by a lack of effective vaccines and treatments due to increasing trends in antimicrobial resistance. This review summarizes the latest data on the epizootic situation of M. bovis infections and new sources/routes of transmission of the infection, and discusses the progress in diagnostics. The review includes various recommendations and suggestions which could be applied to infection control programs.

Effects of citric acid on fermentation characteristics and bacterial diversity of Amomum villosum silage

To study the effects of citric acid on fermentation process of Amomum villosum silage, A. villosum was ensiled without or with 1%, 2% citric acid and fermentation parameters and bacterial diversity were analyzed after 3, 7, 14, 30 days ensiling, respectively. Citric acid treated silages had lower dry matter loss (1.83% vs 2.23%), pH (3.84 vs 6.02), ammonia-N (0.33 vs 1.79 g/kg DM) and coliform bacteria number (<2.00 vs 7.27 log₁₀ CFU/g FM) than the control after 30 days ensiling. The relative abundance of lactic acid bacteria, Pediococcus and Lactobacillus increased, whereas undesirable microorganisms like Enterobacter, Escherichia-Shigella and Pantoea decreased in citric acid treated A. villosum silage. These results indicated that quality A. villosum silage could be obtained by citric acid addition.