Methods to detect potability of water samplevimala rodhe
Water is precious and it is the base for living, Several disease causing pathogens are transmitted through water. There are various methods to detect the presence of pathogens in drinking water samples.Some of the methods to detect microbiological quality of water are discussed.
Methods to detect potability of water samplevimala rodhe
Water is precious and it is the base for living, Several disease causing pathogens are transmitted through water. There are various methods to detect the presence of pathogens in drinking water samples.Some of the methods to detect microbiological quality of water are discussed.
Detection and Enumeration of Coliforms in Ganga WaterTuhin Samanta
MPN is most generally applied for quality testing of water i.e to guarantee whether the water is protected or not as far as microorganisms present in it. A gathering of microscopic organisms normally alluded as fecal coliforms go about as a pointer for fecal pollution of water. The nearness of not many fecal coliform microbes would show that a water presumably contains no disease‑causing living beings, while the nearness of huge quantities of fecal coliform microscopic organisms would demonstrate an extremely high likelihood that the water could contain disease‑producing life forms making the water hazardous for utilization.
In Vitro Antibacterial Activities of Cochlospermum planchonii Roots Crude Ext...iosrjce
The antibacterial activities of the methanolic, hot water, chloroform and petroleum ether of
Cochlospermum planchonii root extracts on some clinical bacterial isolates and reference organisms were
investigated using conventional microbiological and microdilution indicator technique. Phytochemical
screenings were also carried on the extracts. The root extracts of the plant exhibited antibacterial activities
against reference strains and clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus
aureus, Shigella flexneri, and Salmonella typhii. However, the susceptibility pattern of the bacteria did not
differ significantly from each other (p>0.05). The methanolic root extracts exhibited the highest antibacterial
activity, its minimum inhibitory concentration (MIC) ranging between 1.25 mg/ml and 5.00mg/ml; and its zones
of inhibition diameter on the various test microorganisms ranging between 8mm and 12mm. The petroleum
ether extracts had the weakest antibacterial activity, with minimum inhibitory concentration of 5.00mg/ml and
its zones of inhibition diameter ranging between 4mm and 7mm. The bioactive constituents in the plant were
alkaloids, tannins, saponins, cardiac glycosides, and sterols. The methanolic extracts of root appeared to be
more biologically active than other extracts and may be more useful in treating human infections caused by
these pathogens.
Objective: To evaluate the antibacterial effects of 4 different cavity disinfectants on Streptococcus mutans, Lactobacillus acidophilus, and Enterococcus faecalis bacteria in different time periods.
Study Design: The antibacterial effects of Cavity Cleanser, Tubulicid Red Label, Chloraxid 2%, and Oxygenated Water cavity disinfectant solutions on E. faecalis (ATCC 29212), S. mutans (ATCC 25175), and L. acidophilus (RSKK 03037) bacterial strains were evaluated by disk diffusion method. In the study where vancomycin antibiogram disc constituted the positive control group, physiological saline solution was used as the negative control group. Standard, sterile, blank antibiogram discs of 5 mm in diameter, in which 15 μL of each material were added, were placed on agar plates at 2.5–3 cm intervals. The inhibition zone diameters formed around the discs that were left to incubate for 24–48 hours at 37°C were measured in millimeters. Statistical analysis of the data was performed using one-way analysis of variance, Kolmogorov-Smirnov, Levene, and Bonferroni tests.
Results: At the end of the study the solutions tested showed a statistically significant antibacterial effect on all bacterial strains used (p<0.05). Cavity Cleanser disinfectant containing 2% chlorhexidine showed the highest antibacterial effect on S. mutans and L. acidophilus, and benzalkonium-containing Tubulicid Red disinfectant on E. faecalis.
Conclusion: The antibacterial effect of all cavity disinfectants used in the study was found to be higher at the end of the 48th hour than at the end of the 24th hour, but there was no statistically significant difference (p>0.05).
Keywords: antibacterial agents; antibacterial effect; cavity disinfectants; chlorhexidine; contamination; dental caries; disinfection; disc diffusion; gram-negative bacteria; gram-positive bacteria
Detection and Enumeration of Coliforms in Ganga WaterTuhin Samanta
MPN is most generally applied for quality testing of water i.e to guarantee whether the water is protected or not as far as microorganisms present in it. A gathering of microscopic organisms normally alluded as fecal coliforms go about as a pointer for fecal pollution of water. The nearness of not many fecal coliform microbes would show that a water presumably contains no disease‑causing living beings, while the nearness of huge quantities of fecal coliform microscopic organisms would demonstrate an extremely high likelihood that the water could contain disease‑producing life forms making the water hazardous for utilization.
In Vitro Antibacterial Activities of Cochlospermum planchonii Roots Crude Ext...iosrjce
The antibacterial activities of the methanolic, hot water, chloroform and petroleum ether of
Cochlospermum planchonii root extracts on some clinical bacterial isolates and reference organisms were
investigated using conventional microbiological and microdilution indicator technique. Phytochemical
screenings were also carried on the extracts. The root extracts of the plant exhibited antibacterial activities
against reference strains and clinical isolates of Escherichia coli, Pseudomonas aeruginosa, Staphylococcus
aureus, Shigella flexneri, and Salmonella typhii. However, the susceptibility pattern of the bacteria did not
differ significantly from each other (p>0.05). The methanolic root extracts exhibited the highest antibacterial
activity, its minimum inhibitory concentration (MIC) ranging between 1.25 mg/ml and 5.00mg/ml; and its zones
of inhibition diameter on the various test microorganisms ranging between 8mm and 12mm. The petroleum
ether extracts had the weakest antibacterial activity, with minimum inhibitory concentration of 5.00mg/ml and
its zones of inhibition diameter ranging between 4mm and 7mm. The bioactive constituents in the plant were
alkaloids, tannins, saponins, cardiac glycosides, and sterols. The methanolic extracts of root appeared to be
more biologically active than other extracts and may be more useful in treating human infections caused by
these pathogens.
Objective: To evaluate the antibacterial effects of 4 different cavity disinfectants on Streptococcus mutans, Lactobacillus acidophilus, and Enterococcus faecalis bacteria in different time periods.
Study Design: The antibacterial effects of Cavity Cleanser, Tubulicid Red Label, Chloraxid 2%, and Oxygenated Water cavity disinfectant solutions on E. faecalis (ATCC 29212), S. mutans (ATCC 25175), and L. acidophilus (RSKK 03037) bacterial strains were evaluated by disk diffusion method. In the study where vancomycin antibiogram disc constituted the positive control group, physiological saline solution was used as the negative control group. Standard, sterile, blank antibiogram discs of 5 mm in diameter, in which 15 μL of each material were added, were placed on agar plates at 2.5–3 cm intervals. The inhibition zone diameters formed around the discs that were left to incubate for 24–48 hours at 37°C were measured in millimeters. Statistical analysis of the data was performed using one-way analysis of variance, Kolmogorov-Smirnov, Levene, and Bonferroni tests.
Results: At the end of the study the solutions tested showed a statistically significant antibacterial effect on all bacterial strains used (p<0.05). Cavity Cleanser disinfectant containing 2% chlorhexidine showed the highest antibacterial effect on S. mutans and L. acidophilus, and benzalkonium-containing Tubulicid Red disinfectant on E. faecalis.
Conclusion: The antibacterial effect of all cavity disinfectants used in the study was found to be higher at the end of the 48th hour than at the end of the 24th hour, but there was no statistically significant difference (p>0.05).
Keywords: antibacterial agents; antibacterial effect; cavity disinfectants; chlorhexidine; contamination; dental caries; disinfection; disc diffusion; gram-negative bacteria; gram-positive bacteria
Evaluation of Bactericidal and BacteriostaticRajsingh467604
What are disinfectants?
As per the definition given by WHO ( World health organization ) : a disinfectant is a chemical agent, which destroys or inhibits growth of pathogenic microorganisms in the non-sporing or vegetative state.
Why Evaluation?
Evaluation of disinfectants is used to check the ability or efficacy of any disinfectant against specific microorganisms to establish its effectiveness.
Evaluation tests of bactericide.
1. RIDEAL WALKER TEST
This test is also known as the phenol coefficient test,in which any chemical is compared with phenol for its antimicrobial activity.
The result is shown in the form of phenol coefficient.
▪ If a phenol coefficient of a given test disinfectant is less than 1, it means that disinfectant is less effective than phenol.
▪ If a phenol coefficient of a given test disinfectant is more than 1, it means that disinfectant is more effective than phenol.
Procedure
1.1 Different dilutions of the test disinfectant and phenol are prepared and 5 ml of each dilution is inoculated with 0.5ml of the 24 hour growth culture of the organisms.
1.2 All tubes(Disinfectant + organisms & phenol + organisms) are placed in a water bath ( at 17.5° C)
1.3 Subcultures of each reaction mixture are taken and transferred to 5ml sterile broth at an interval of 2.5 minutes from zero to 10 mintues.
1.4 Broth tubes are incubated at 37° C for 2 to 3 days & examined for the presence or absence of the growth.
1.5 Then the Rideal Walker coefficient is calculated :
2. CHICK MARTIN TEST.
CHICK MARTIN test is performed in the much similar way as the RIDEAL Walker test but with a little variation.
Principle : This test is carried out in the presence of organic matter like 3% human feces or dried yeast.
Procedure
2.1 Serial dilutions of test solution and phenol is prepared in distilled water.
2.2 To this 3% yeast suspension is also added.
2.3 To this solution the S. typhi is added
2.4 After contact time of 30 mins the above mixture is transferred to the freshly prepared 10 ml of broth.
2.5 The test tubes are incubated at 37°C for 48 hours.
2.6 Presence or absence of the growth is calculated.
Evaluation tests of Bacteriostatic.
1. Tube dilution & Agar plate Method
1.1 The chemical agent is incorporated into nutrient broth or agar medium and inoculated with test micro-organisms.
1.2 These tubes are incubated at 30° TO 35°C for 2 to 3 days and then the results in the form of turbidity or colonies are observed.
1.3 The results are recorded and the activity of the given disinfectant is compared.
2. Cup plate method
2.1 Agar is melted and cooled at 45° Celsius.
2.2 Then inoculated with test micro-organisms and poured into a sterile petri plate.
2.3 In the cup plate method, when the inoculated agar has solidified, holes around 8mm in diameter are cut in the medium with a steel cork borer.
2.4 Now the antimicrobial agents are directly placed in the holes.
In vitro controlling of selected human diarrhea causing bacteria by clove ext...Open Access Research Paper
Antibacterial activity of clove extracts (Syzygium aromaticum L.) was proven against five diarrhea causing bacteria. This was further confirmed when compared with commonly used three commercial antibiotics (ciprofloxacin, tetracycline and erythromycin) as a positive control. Significant differences (P<0.0001) were observed in the effect of the antimicrobial agents (clove extracts and antibiotics), and in the sensitivities of the bacterial species (P<0.0001) to the antimicrobial agents. Clove extracts had significant (P<0.001) activity with the acetone extract demonstrating highest activity followed by antibiotics and other extracts against tested bacteria. The zone of inhibition of clove extracts was ranged from 7.33 to 12.00 mm whereas in antibiotics, it was 0.00 to 11.67 mm. Of all the bacteria, Salmonella typhimurium was the most susceptible against all of the extracts as well as concentrations of clove, while low MIC (180 mgml-1) and MBC (680 mgml-1) of the extracts were observed against Shigella dysenteriae. Consequently, clove has a significant antidiarrheal activity and it could be used as an effective antibacterial agent, alternative to the use of antibiotics.
TESTING OF DISINFECTANT CLASSES OF DISINFECTANTS METHOD FOR TESTING DISINFEC...VeerendraMaravi
HISTORY
INTRODUCTION
CLASSES OF DISINFECTANTS
METHOD FOR TESTING DISINFECTANTS
CARRIER TEST
CAPACITY TEST
SUSPENSION TESTS
PRACTICAL TEST
IN USE TEST
Testing schemes
TEST ORGANISMS
Pharmacological activity of the methanolic extract of sea urchins against esc...Innspub Net
This study elucidated the pharmacological potential of sea urchins using methanol as extracting medium. The antibacterial potential was evaluated using the paper disc method and zone of inhibition against Escherichia coli and Staphylococcus aureus was measured. Antioxidant properties of sea urchins were evaluated using DPPH radical scavenging assay. Three species of sea urchin randomly collected along the intertidal zone of Diguisit, Baler Aurora were identified using diagnostic keys by the National Museum of the Philippines and they were identified as follows; Echinothrix diadema, Echinometra mathaei, and Echinometra oblonga. E. diadema recorded the highest diameter zone of inhibition against E. coli and S. aureus after 24 hours of incubation with 11.03 ± 1.75mm and 13.52 ± 1.13mm respectively while E. mathaei only inhibited S. aureus with zone of inhibition of 9.27 ± 2.06mm in 24 hours of incubation as well. As the zone of inhibition prolongs, the zone of inhibition decreases as observed in 48 hours of incubation. E. oblonga did not show inhibitoy effect, however it recorded the highest radical scavenging activity with 64.46% among the three species of sea urchins. This was followed by E. mathaei (51.52%) and E. diadema (37.38%). All collected species manifested antioxidant potential. Based on the results, the collected species of sea urchins has a pharmacological potential.
Respuesta a Solicitud de Estudios de Calidad de Agua, Municipio San Luis Poto...ricguer
Cuando existe "Transparencia de la Información", se puede acceder por cuaquier medio. Sin embargo, el Municipio de San Luis Potosi, obliga a que si alguien quiere conocer la información pública, se presente, con identificación y en los horarios que ellos imponen para que hagan el favor de enseñar la información pública. Esta es una aberración de la "Transparencia".
Estudios de Calidad de Agua, Municipio de Monterrey, Nuevo León 2014 Estudios...ricguer
PRIMER ATLAS DE CALIDAD DE AGUA POR COLONIA DE MEXICO : http://www.ecodomestico.com
Calidad de Agua del Municipio de Monterrey, Estado de Nuevo León, México. En este estudio se muestran exclusivamente los Análisis Fisico-químicos. No se entrega la Información por Colonia y en su lugar se entregan los Estudios por POZOS, TANQUES Y RED que existe en diversos puntos del Municipio de Monterrey. Cabe destacar, que de los 46 parámetros que indica la norma, se entregan 42 parámetros, faltando únicamente 4 parámetros, totalmente contrario a lo que entregó, por ejemplo el municipio de Toluca, en el Estado de México. Los niveles de Dureza son elevados en general. Es necesario monitorear los niveles de Cianuro, Fluoruros, Arsénico, Aluminio, Sulfatos y Sodio, ya que podrían variar y sobrepasar la norma establecida fácilmente y ser altamente peligrosos para la Salud.
Estudios de Calidad de Agua, Municipio de Monterrey, Nuevo León 2014 Cloro Re...ricguer
PRIMER ATLAS DE CALIDAD DE AGUA POR COLONIA DE MEXICO : http://www.ecodomestico.com
Calidad de Agua del Municipio de Monterrey, Estado de Nuevo León, México. En este estudio se muestran exclusivamente los Análisis de Cloro Residual. No se entrega la Información por Colonia y en su lugar se entregan los Estudios de Cloro Residual que existe en diversos puntos del Municipio de Monterrey.
Calidad de Agua del Municipio de Aguascalientes, Aguascalientes Mexico junio ...ricguer
Se solicita la Calidad de Agua del Municipio de Aguascalientes, Estado de Aguascalientes, México. NO NOS ENTREGAN LOS ESTUDIOS, pero la respuesta es que : SE CLASIFICA COMO INFORMACION RESERVADA, porque ".. su divulgamiento pondría en peligro la estabilidad Financiera del municipio...".
Según el titular, porque estan en proceso un análisis de inversión para equipamiento de los pozos.
Sin embargo, no exsite relación alguna para impedir a los ciudadanos el conocer la Calidad de Agua que distribuyen. Este "Clasificación de Información Reservada" es un claro signo que puede indicar Alertas de Corrupción en este ayuntamiento o de ocultamiento de la Información, a fin de que la población no tenga ni la mas mínima idea del probable veneno que distribuyen a los ciudadanos. En todo caso, es un raro, pero típico caso de Ocultamiento de la Información en detrimento de la población a la que dicen servir y de la cual se sirven con un inmerecido salario.
Calidad de Agua de Cancún, Municipio Benito Juárez, Quintana Roo. Mayo 2014 ...ricguer
PRIMER ATLAS DE CALIDAD DE AGUA POR COLONIA DE MEXICO : http://www.ecodomestico.com
Calidad de Agua de Cancún, dentro del Municipio de Benito Juárez, en el estado de Quintana Roo, México. Faltan 37 parámetros de medición establecidos por la Norma Oficial Mexicana de los 46 establecidos. 3 de estos solo aparecen ls encabezados. Con los Datos Proporcionados, este municipio cuenta con una de las peores Calidades de Agua de Todo el País, administrada por una compañia privada llamada AGUAKAN.
Los niveles de Nitratos se encuentran muy por encima de los niveles máximos de la norma. Los elevados niveles de Cloruros y de Solidos Disueltos Totales -SDT- (sales y residuos orgánicos) hacen que el agua sea prácticamente imbebible.En Estados Unidos, el límite máximo de SDT es de 500, mientras que en México se permiten 1000 ppm.
El nivel de Dureza (calcio y magnesio) es generalmente muy alto en la casi totalidad de las fuentes que suministran agua. La elevada dureza del agua puede generar hipercalcemia, insuficiencia renal, hipertiroidismo o cáncer de pulmón, además que las tuberías se tapan por la acumulación de calcio.
La empresa AGUAKAN presume en su página de internet el contar con el Premio Nacional de Cloración, olvidando los 45 parámetros restantes y obligatorios para proporcionar Agua Potable. En este caso NO EXISTE DIFERENCIA entre una empresa privada y una pública para entregar una Calidad de agua que sea aceptable y POTABLE.
Relación entre concentraciones de aluminio en el agua potable y el alzheimer ...ricguer
Estudio Realizado en el sudoeste de Francia en Dorgogne y Gironde en 3,777 personas iniciando en 1988 y 1989, con una duración en el seguimiento por 8 años. Se investigaron los efectos de la presencia de Aluminio en el Agua Potable y sus consecuencias : Se confirman las consecuencias de personas con Alzheimer entre mayor concentraciones de Aluminio. Se corroboran las hipótesis de varios estudios mas : Aluminio = Alzheimer http://www.ecodomestico.com
Riesgos Graves del aluminio en la salud humana frricguer
En este estudio realizado en colaboración con la AFSSA (L'Agence française de sécurité sanitaire des aliments) se puede observar a partir de la página 41, los daños y la relación del consumo de este metal con la enfermedad del Alzheimer y numerosas enfermedades mas. El evitar consumirlo, significará reducir las probabilidades de llegar a padecer esta grave enfermedad. http://www.ecodomestico.com
Calidad de Agua Municipio de tepic, estado de Nayarit, Julio 2013 INFOPLACITUMricguer
PRIMER ATLAS DE CALIDAD DE AGUA DE MEXICO : http://www.ecodomestico.com
Estudios Calidad de Agua de Tepic Nayarit. No entregan análisis de 2013 porque estos no los han realizado (ya que consideran que no es importante) o porque simplemente no desean que se sepa la calidad que proveen a los ciudadanos.
38 experts on bpa panel consensus statement. effects in animals and potential...ricguer
Un conjunto de 38 prestigiados científicos de todo el mundo alertan sobre el potencial nocivo y los impactos de exposición al Bisphenol A para la salud humana.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
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These lecture slides, by Dr Sidra Arshad, offer a quick overview of physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
The prostate is an exocrine gland of the male mammalian reproductive system
It is a walnut-sized gland that forms part of the male reproductive system and is located in front of the rectum and just below the urinary bladder
Function is to store and secrete a clear, slightly alkaline fluid that constitutes 10-30% of the volume of the seminal fluid that along with the spermatozoa, constitutes semen
A healthy human prostate measures (4cm-vertical, by 3cm-horizontal, 2cm ant-post ).
It surrounds the urethra just below the urinary bladder. It has anterior, median, posterior and two lateral lobes
It’s work is regulated by androgens which are responsible for male sex characteristics
Generalised disease of the prostate due to hormonal derangement which leads to non malignant enlargement of the gland (increase in the number of epithelial cells and stromal tissue)to cause compression of the urethra leading to symptoms (LUTS
2. autoclaves, and other expensive equipment). Most studies do not include viruses due the
inherent technical degree of difficulty in separating the virions from the disinfectant solution
before assay in mammalian host cells, which are even more susceptible to the toxic effects of
the disinfectant than the viruses. Consequently, assumptions are often based on minimal data
with bacteria.
This report describes our search for a relatively non-corrosive disinfectant that could be used
to decontaminate stainless steel biosafety cabinet surfaces and have maximum killing capacity
against the spores of Bacillus anthracis. An avirulent B. anthracis (Sterne) strain was selected
as an assay system to evaluate the efficacy of a commercially available disinfectant, Vimoba™
(Quip Laboratories, Wilmington, DE, USA) containing chlorine dioxide as the principal active
ingredient. Chlorine dioxide gas has been used to kill B. anthracis spores, as reviewed by Spotts
Whitney et al. following the 2001 bioterrorism attack in the USA.1
Many laboratories working with B. anthracis spores use various concentrations (5-50%) of
household bleach (sodium hypochlorite); however, this is corrosive and causes pitting of
stainless steel. An alternative to bleach is to use solutions of chlorine dioxide, a gas dissolved
in water. Chlorine dioxide is approximately ten times more soluble than chlorine, extremely
volatile, and can be easily removed from dilute aqueous solutions with minimal aeration.3 It
is also a potent oxidiser, accepting a maximum of five electrons during its reduction to form
the Cl- ion.4 In this study, we sought to determine whether Vimoba would have biocidal activity
against B. anthracis spores and reduce the need for high concentrations of bleach in
decontaminating laboratory surfaces.
Methods
Bacteria
Bacillus anthracis Sterne was acquired from T.M. Koehler in the Department of Microbiology
and Molecular Genetics, University of Texas - Houston Health Science Center Medical School,
Houston, Texas.
Preparation of B. anthracis spores
Spores were prepared from B. anthracis Sterne by growing the bacteria at 37°C on blood agar
plates and scraping the growth from the plates into 2× Schaeffer’s sporulation medium (pH
7.0) [16 g/L Difco Nutrient Broth, 0.5 g/L MgSO4 ·7H2O, 2.0 g/L KCl, and 16.7 g/L 4-
morpholinepropanesulphonic acid, 0.1% glucose, 1 mM Ca(NO3)2, 0.1 mM MnSO4, and 1
μM FeSO4]. Cultures were grown at 37°C with gentle shaking (80-90 rpm) for 24 h, after which
the suspension was diluted five-fold with sterile distilled water. After 10-11 days of continuous
shaking, sporulation was confirmed at >99% via phase contrast microscopy, and the spores
were centrifuged at 587 g in a sealed-carrier centrifuge (Beckman Coulter, Inc., Fullerton, CA,
USA) at 4°C for 15 min. Spore pellets were then washed four times in sterile phosphate-
buffered saline (PBS) and purified by centrifugation through 58% Ficoll Paque (GE Healthcare,
Piscataway, NJ, USA).
Preparation of disinfectant
Vimoba tablets (1.5 g) were purchased from Quip Laboratories, Inc. (Wilmington, DE, USA)
and pulverised inside their sealed envelopes with a mortar and pestle immediately before use.
Chlorine dioxide was generated by adding indicated milligram amounts of powder from the
effervescent Vimoba tablets to water. Disinfectant solutions were prepared fresh for every
experiment, unless stated otherwise in the text. For some experiments, the Vimoba powder was
added to 2-5% household bleach diluted in water. The latter disinfectant was referred to as
Vimoba-bleach cocktail.
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3. Disinfectant assay
All experiments were performed inside a Class II biosafety cabinet. Initial experiments to test
the potency of Vimoba in killing B. anthracis Sterne were performed by mixing 50 μL of spores
(1 × 108 cfu) with an equal volume of the disinfectant solution diluted as indicated in capped
microfuge tubes for 3 min. The spores were quickly separated from the disinfectant by diluting
and washing with 1 mL of water and centrifugation (14 000 rpm). Subsequently, the viability
of the spores was assessed by serial dilution and plating on to 5% sheep blood agar plates. In
later experiments, the spore suspension (1 × 108 cfu) was spread on to 13 mm diameter circular
areas on the sterile surface of either stainless steel or polystyrene sheets before spraying with
or pipetting 500 μL of disinfectant on to the spots. After 3 min incubation at room temperature,
1 mL of water was added and the entire suspension was aspirated from the surface and spread
on to the surface of four or five blood agar plates. The total number of surviving spores was
estimated by plate counts. In some experiments, the disinfectant alone was first sprayed on to
surfaces to evaluate the effect of chlorine dioxide vaporisation on the potency of the
disinfectant. Samples of the spore suspension (50 μL; 1 × 108 cfu) were added to the spot for
3 min, the mixture was recovered from the surface and the survivors were determined by serial
dilution and plating on 5% sheep blood agar plates.
Results
Initial tube dilution experiments were performed to assess the potency of freshly prepared
Vimoba in killing B. anthracis Sterne spores. Table I represents a typical experiment in which
50 μL aliquots of the disinfectant, prepared from 0, 2.5, 5.0, and 10.0 mg/mL Vimoba tablets,
were distributed into microfuge tubes. After adding an equal volume of B. anthracis Sterne
spores (1 × 108 cfu) and incubating at room temperature for 3 min, the microfuge tubes were
diluted, centrifuged, and washed twice with 1 mL PBS. Subsequently, the suspensions were
diluted and plated on 5% sheep blood agar.
Table I shows the disinfectant potency when mixed in a closed tube with B. anthracis Sterne
spores for 3 min. Vimoba was highly effective in killing B. anthracis Sterne spores in a very
short period (3 min), and complete inactivation of 8 log10 of spores occurred with 10 mg/mL.
The potency was proportionately less with lower concentrations. This dose-response
experiment was very reproducible and was also observed with B. anthracis Ames spores (data
not shown). Consequently, Vimoba was considered as a potential sporicidal disinfectant for
routine contact disinfection of biosafety cabinets, carts, animal cages, and other surfaces
contaminated with B. anthracis Ames spores.
As a further test, we assessed its capacity to kill B. anthracis Sterne spores on contaminated
surfaces. We spotted 1 × 108 cfu B. anthracis spores on to 13 mm diameter circular areas on
the sterilised stainless steel work surface within a biosafety cabinet. Without allowing the areas
to dry, we sprayed or pipetted various concentrations (10-100 mg/mL) of Vimoba on to the
spots, waited 3 min, and then diluted and cultured the areas by transferring the suspension to
sectors of blood agar plates with sterile plastic ‘L’ rods. Qualitative culture of the spots revealed
many survivors even at the higher concentrations of the disinfectant with little difference
whether the Vimoba was sprayed or pipetted on to the surface (data not shown).
Since the disinfectant would usually be applied by spraying onto surfaces of equipment to
decontaminate them, we developed a quantitative experimental approach for testing the effect
of spraying or pipetting the disinfectant onto a work surface. Briefly, we sprayed or pipetted
~500 μL Vimoba onto 13 mm circular areas on each surface (sterilised 304 stainless steel work
surface and sterile polystyrene Petri dish lids) and allowed them to remain as a thin film for 3
min. Fifty microlitres of 1 × 108 B. anthracis Sterne spores were added to the spots and allowed
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4. to remain for another 3 min. After dilution, quantitative plate counts were performed using
blood agar plates incubated at 37°C.
The effect of spraying or pipetting Vimoba onto stainless steel or plastic surfaces for 3 min
prior to mixing with 1 × 108 cfu B. anthracis spores is summarised in Table II. The negative
control is shown in the top row, which shows the number of spores added (1 × 108 cfu). The
second row shows the results of a positive control (8 log10 kill) performed by mixing 20 mg/
mL Vimoba with a 50 μL spore suspension (1 × 108 cfu). The third and fourth rows show that
the Vimoba in contact with a stainless steel surface reduced its killing efficiency to <1 log10
of B. anthracis spores. By comparison, spraying or pipetting Vimoba on to a polystyrene plastic
surface resulted in a 1 log10 reduction in spore viability.
In order to compensate for the loss of potency of Vimoba when it was sprayed or pipetted onto
a surface, an experiment was performed in which various concentrations (2-5%) of household
bleach were used to prepare the Vimoba solution, instead of water. Using the disinfectant assay
spray method developed for the previous experiment (Table II), four 1 L spray bottles were
filled completely with Vimoba solution prepared in 0%, 2%, 4%, or 5% bleach. Each solution
was sprayed on to a sterile stainless steel surface and after 3 min, 50 μL aliquots were aspirated
and pipetted into microfuge tubes containing 50 μL of 1 × 108 cfu B. anthracis Sterne spores.
Table III shows that freshly prepared full bottles of Vimoba alone (5 mg/mL) reduced spore
viability by 3.1 log10, but 24 h later it retained little if any potency against B. anthracis Sterne
spores. When the Vimoba was supplemented with as little as 2% bleach, full potency was
restored enabling it to kill 8 log10 of B. anthracis Sterne spores with stability for a period of
24 h. Clearly, the optimum concentration of bleach was 5%, because it allowed the disinfectant
to be used for at least one week. However, in situations where corrosion-sensitive equipment
is being decontaminated, it might be advisable to use a low concentration of bleach (e.g. 1-2%)
and prepare it fresh daily. It should also be noted in these experiments that the Vimoba
concentration was reduced from 10 to 5 mg/mL, striving to take advantage of the enhanced
effect of Vimoba and bleach.
Considering the volatility of chlorine dioxide in solution, a final experiment was designed to
determine the effect of residual volume of Vimoba solution remaining in 1 L plastic spray
bottles on stability. Reasoning that the surface:air ratio likely is important in the rate with which
chlorine dioxide vaporises from the solution. Therefore, using the same assay spray method
used in earlier experiments, several 1 L plastic spray bottles containing various volumes
(50-1000 mL) of Vimoba (5 mg/mL) were prepared with 5% bleach. We noted that on the day
of preparation, there was no difference in potency among the various bottles, with each reducing
the viability of B. anthracis Sterne spores by 8 log10 (Table IV). It became clear that bottles
containing lower volumes of disinfectant were stable for shorter periods of time. For example,
a 1 L bottle nearly empty (50 mL) could kill only 4.3 log10 of the 1 × 108 cfu of the B.
anthracis Sterne spores by 24 h, while by the second day had lost all disinfectant capacity.
When the 1 L bottles were filled with 250-500 mL, the disinfectant retained full potency for
four days and proportionately lesser kill capacity by the end of seven days. As long as the 1 L
bottles were three-quarters full or greater, the disinfectant retained full potency for seven days,
that is, the capacity to kill 8 log10 of B. anthracis Sterne spores.
Discussion
Chlorine dioxide gas has been used previously to decontaminate indoor materials and sanitise
water supplies and equipment; however, we report for the first time that chlorine dioxide in
solution rapidly kills B. anthracis spores.1,4 The disinfectant assay parameters that we
established employed chemically resistant B. anthracis spores as a target and 3 min as the
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5. maximum period of exposure. We demonstrated by tube dilution that Vimoba had a potent
biocidal effect on B. anthracis Sterne spores in a closed tube assay system, reducing spore
viability by 8 log10 to an undetectable number in 3 min contact time. This was achieved by
preparing the chlorine dioxide solution by dissolving various amounts of the crushed
effervescent tablet (2.5-10.0 mg/mL) in water. All experiments, except where indicated, were
performed with freshly prepared disinfectant solutions. A 10 mg/mL solution produced
sufficient chlorine dioxide to completely kill 1 × 108 cfu of B. anthracis Sterne spores in a 3
min period. A 50% decrease in chlorine dioxide concentration to 5 mg/mL resulted in a 4.34
log10 reduction in spore viability. Further, by reducing the amount of chlorine-dioxide-
generating powder from 10 to 2.5 mg/mL, the disinfectant potency was reduced proportionately
to 1.57 log10.
It was noted that the disinfectant exerted a potent sporicidal effect in closed tubes. Typically
such observations should be sufficient to justify using the disinfectant in a laboratory or hospital
setting; however, additional experiments were performed to mimic the ‘real world’ scenario
of how the disinfectant would be used. Thus, we contaminated a sterile stainless steel work
surface with 13 mm spots of a suspension of B. anthracis Sterne spores (1 × 108 cfu), and then
sprayed or pipetted Vimoba onto them for 3 min. Spraying or pipetting Vimoba onto the
stainless steel work surface and spreading it out into a thin film resulted in a significant
reduction in disinfectant potential, limiting the kill capacity to approximately 1 log10 in 3 min.
Having already demonstrated that chlorine dioxide had a potent sporicidal effect in closed
microfuge tubes, we determined why the disinfectant lost so much capacity to kill the spores
when it was sprayed onto contaminated surfaces. It was thought that some loss of disinfectant
potential may have been due to oxidation of iron from the stainless steel surface, since chlorine
dioxide scavenged electrons and was known to be reduced to chlorite, chlorate, and chloride
ions. In Table II, we observed that the stainless steel surface played a minimal role, compared
with plastic, in reducing the potency of the disinfectant. Additionally, it made no difference
whether the disinfectant was sprayed or pipetted onto the work surface; both resulted in the
formation of a thin film with poor sporicidal results.
The majority of the loss in potency of Vimoba during application was postulated to result from
the rapid vaporisation of chlorine dioxide gas from the disinfectant solution at the work surface.
The flow of air within the biosafety cabinet could have promoted evaporation of the chlorine
dioxide; however, spreading the disinfectant out into a thin film seemed to be important in
diminishing potency. It is only logical that the application process would increase vaporisation
of the gaseous chlorine dioxide from the solution. Rather than discarding a potentially excellent
disinfectant from further use, we sought to improve its stability and killing capacity by
supplementing Vimoba with various concentrations of household bleach to improve its
disinfectant action and increase its stability. It was observed upon assay of the Vimoba-bleach
cocktail that addition of bleach to Vimoba restored it to full potency and extended its storage
life even when sprayed on to surfaces. In doing so, we were able to reduce the Vimoba
concentration by 50% (5 mg/mL instead of 10 mg/mL) and prepare it in 2-5% bleach. While
2% bleach supplement worked well when used immediately or within one day, 5% bleach was
considered much more reliable in killing B. anthracis spores for a period of seven days. The
combination of Vimoba and bleach was synergistic in killing B. anthracis spores (Table III),
resulting in greater combined potency than the anticipated additive effect of the two
components.
A disinfectant capable of reducing B. anthracis spore viability by 8 log10 in 3 min contact time
must be considered an excellent and reliable reagent. Few investigators would argue with the
presumption that such a disinfectant would likely exert an equal or greater effect on viruses or
vegetative cells of bacteria. The latter are considerably more susceptible to other disinfectants
than are spores, which tend to be very resistant to chemicals. As an example, B. anthracis
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6. spores are often stored in 1% phenol without loss of viability.5 Further, the criteria posed are
actually similar to those used as criteria for sterilisers based on steam, vaporised hydrogen
peroxide, or ethylene oxide. It is routine practice to expect a 6 log10 reduction in viability of
spores from B. atropheus or B. stearothermophilus as an indicator of sterility. Only one other
property that might be expected from an excellent disinfectant is for it to be totally non-
corrosive. Vimoba contains corrosion inhibitors, although chlorine dioxide gas is only weakly
corrosive.6 Corrosion testing is in progress to determine whether the Vimoba-bleach cocktail
will be corrosive for metals such as stainless steel.
The Vimoba-bleach cocktail (5 mg/mL; 5%) was shown to be stable for at least seven days
when stored virtually full in sealed plastic spray bottles. As summarised in Table IV, we
examined the disinfectant potency when bottles were only partially filled. It became apparent
that 1 L plastic spray bottles that were at least three-quarters full maintained maximum killing
potential for B. anthracis Sterne spores for seven days; however, bottles that were one-quarter
to one-half full maintained maximum potency in killing B. anthracis Sterne spores for four
days. An essentially empty bottle (50 mL) was fully potent only when made up fresh.
It was concluded that Vimoba was a potent disinfectant in closed containers; however,
substantial reduction in potency occurred when it was sprayed or pipetted on to contaminated
surfaces as a thin film. In order to compensate for the loss of chlorine dioxide, Vimoba was
prepared in 5% bleach (0.3% sodium hypochlorite) and found to be a potent formulation,
remaining stable for at least seven days. Thus, when applied as a spray to decontaminate
surfaces, Vimoba should be supplemented with dilute bleach in order to have maximum
potency.
Acknowledgments
Funding sources
This study was performed with support from contract N01-AI-30065 from the National Institute of Allergy and
Infectious Diseases. No financial support was requested or provided by the manufacturer of Vimoba™ (Quip
Laboratories, Wilmington, DE, USA).
References
1. Spotts Whitney EA, Beatty ME, Taylor TH, et al. Inactivation of Bacillus anthracis spores. Emerg
Infect Dis 2003;9:623–627. [PubMed: 12780999]
2. Davis CP, Shirtliff ME, Trieff NM, Hoskins SL, Warren MM. Quantification, qualification, and
microbial killing efficiencies of antimicrobial chlorine-based substances produced by iontophoresis.
Antimicrob Agents Chemother 1994;38:2768–2774. [PubMed: 7695260]
3. US Environmental Protection Agency. Chlorine dioxide. Alternative disinfectants and oxidants. EPA
guidance manual; Apr. 1999 p. 4-1.p. 4-28.to
4. Hubbard H, Poppendieck D, Corsi RL. Chlorine dioxide reactions with indoor materials during building
disinfection: surface uptake. Environ Sci Technol 2009;43:1329–1335. [PubMed: 19350899]
5. Ivins BE, Pitt MLM, Fellows PF, et al. Comparative efficacy of experimental anthrax vaccine
candidates against inhalation anthrax in rhesus macaques. Vaccine 1998;16:1141–1148. [PubMed:
9682372]
6. Bohner HF, Bradley RL. Corrosivity of chlorine dioxide used as sanitizer in ultrafiltration systems. J
Dairy Sci 1991;74:3348–3352.
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7. NIH-PAAuthorManuscriptNIH-PAAuthorManuscriptNIH-PAAuthorManuscript
Chatuev and Peterson Page 7
TableI
ExposureofB.anthracisSternesporestoVimoba™inmicrofugetubes
Vimobatablet
concentration(mg/mL)
Exposuretime
(min)
No.of
survivors(cfu)
Log10
reduction
%
kill
%
survival
031.0×010800100
2.532.7×1061.5797.32.7
5.034.6×1034.3499.990.01
10.030.081000
J Hosp Infect. Author manuscript; available in PMC 2011 February 1.
8. NIH-PAAuthorManuscriptNIH-PAAuthorManuscriptNIH-PAAuthorManuscript
Chatuev and Peterson Page 8
TableII
ExposureofB.anthracisSternesporestoVimoba™aftercontactwithstainlesssteelorplastic
Vimoba
concentration
(mg/mL)
Disinfectant
treatment
Exposure
time(min)
No.of
survivors
(cfu)
Log10
reduction
%
kill
%
survival
0None31×10800100
10Plastictube
control
3081000
10Sprayedonto
SS
32×1070.78020
10Pipettedonto
SS
32.3×1070.647723
10Sprayedonto
plastic
39×1061.05919.0
10Pipettedonto
plastic
38×1061.1928.0
SS,stainlesssteel.
J Hosp Infect. Author manuscript; available in PMC 2011 February 1.