Jason Warren Freeman, M.D.

• Medical Director, Stroke Program, Sibley Memorial Hospital

https://www.hopkinsmedicine.org/profiles/results/directory/profile/3784557/jason-freeman

From one molecule of butterfat containing one glycerol and three 12-carbon chains The chemoautotroph Acidithiobacillus can obtain energy from the oxidation of arsenic (As3+ As5+) chronic gastritis lasts 40 mg protonix purchase overnight delivery. The following graph shows the normal rate of reaction of an enzyme and its substrate (blue) and the rate when an excess of competitive inhibitor is present (red) gastritis y colitis order discount protonix on-line. The bacterial enzyme streptokinase is used to digest fibrin (blood clots) in patients with atherosclerosis gastritis journal pdf buy generic protonix from india. Rate of reaction With competitive inhibitor Substrate concentration Microbial Growth hen we talk about microbial growth gastritis pathophysiology order protonix online pills, we are really referring to the number of cells gastritis zoloft buy protonix 40 mg on line, not the size of the cells. Microbes that are "growing" are increasing in number, accumulating into colonies (groups of cells large enough to be seen without a microscope) of hundreds of thousands of cells or populations of billions of cells. Although individual cells approximately double in size during their lifetime, this change is not very significant compared with the size increases observed during the lifetime of plants and animals. Many bacteria survive and grow slowly in nutrient-poor environments by forming biofilms. The Serratia marcescens bacteria in the photo may form biofilms on urinary catheters or on contact lenses. Biofilms are frequently sources of health care-associated infections such as the one described in the Clinical Case. By understanding the conditions necessary for microbial growth, we can determine how to control the growth of microbes that cause diseases and food spoilage. We can also learn how to encourage the growth of helpful microbes and those we wish to study. In this article we will examine the physical and chemical requirements for microbial growth, the various kinds of culture media, bacterial cell division, the phases of microbial growth, and the methods of measuring microbial growth. This gram-negative rod produces the pigment prodigiosin, causing bright red colonies when the bacteria grow at room temperature. In the Clinic As a nurse in a plastic surgery clinic, you instruct patients on postsurgical care of their sutures. You tell patients to wash hands before removing bandages, to wash gently around the surgical site with soap and water, and to swab the wound with hydrogen peroxide. One day a patient calls, alarmed that the hydrogen peroxide caused her wound to bubble. Chemical requirements include sources of carbon, nitrogen, sulfur, phosphorus, oxygen, trace elements, and organic growth factors. Physical Requirements Temperature Most microorganisms grow well at the temperatures that humans favor. However, certain bacteria are capable of growing at extremes of temperature that would certainly hinder the survival of almost all eukaryotic organisms. Microorganisms are classified into three primary groups on the basis of their preferred range of temperature: psychrophiles (cold-loving microbes), mesophiles (moderate-temperature­ loving microbes), and thermophiles (heat-loving microbes). Notice that the reproductive rate drops off very quickly at temperatures only a little above the optimum. At either extreme of the temperature range, the reproductive rate is much lower than the rate at the optimum temperature. Each bacterial species grows at particular minimum, optimum, and maximum temperatures. The minimum growth temperature is the lowest temperature at which the species will grow. The optimum growth temperature is the temperature at which the species grows best. The maximum growth temperature is the highest temperature at which growth is possible. This happens presumably because the high temperature has inactivated necessary enzymatic systems of the cell. The ranges and maximum growth temperatures that define bacteria as psychrophiles, mesophiles, or thermophiles are not rigidly defined. Psychrophiles, for example, were originally considered simply to be organisms capable of growing at 0°C. However, there seem to be two fairly distinct groups capable of growth at that temperature. One group, composed of psychrophiles in the strictest sense, can grow at 0°C but has an optimum growth temperature of about 15°C. Most of these organisms are so sensitive to higher temperatures that they will not even grow in a reasonably warm room (25°C). The other group that can grow at 0°C has higher optimum temperatures, usually 20­30°C and cannot grow above about 40°C. Organisms of this type are much more common than psychrophiles and are the most likely to be encountered in low-temperature food spoilage because they grow fairly well at refrigerator temperatures. We will use the term psychrotrophs, which food microbiologists favor, for this group of spoilage microorganisms. Thermophiles Hyperthermophiles Mesophiles Psychrotrophs Psychrophiles Q Why is it difficult to define psychrophile, Rate of growth mesophile, and thermophile It is based on the principle that microbial reproductive rates decrease at low temperatures. Although microbes usually survive even subfreezing temperatures (they might become entirely dormant), they gradually decline in number. Psychrotrophs do not grow well at low temperatures, except in comparison with other organisms; given time, however, they are able to slowly degrade food. Such spoilage might take the form of mold mycelium, slime on food surfaces, or off-tastes or off-colors in foods. The temperature inside a properly set refrigerator will greatly slow the growth of most spoilage organisms and will entirely prevent the growth of all but a few pathogenic bacteria. Refrigerator temperatures; may allow slow growth of spoilage bacteria, very few pathogens. Temperatures in this range destroy most microbes, although lower temperatures take more time. Notice that in this example, the pan of rice with a depth of 5 cm (2 in) cooled through the incubation temperature range of the Bacillus cereus in about 1 hour, whereas the pan of rice with a depth of 15 cm (6 in) remained in this temperature range for about 5 hours. Mesophiles, with an optimum growth temperature of 25­40°C, are the most common type of microbe. Organisms that have adapted to live in the bodies of animals usually have an optimum temperature close to that of their hosts. Low temperatures decrease microbial reproduction rates, which is the basic principle of refrigeration. There are always some exceptions to the temperature responses shown here; for example, certain bacteria grow well at high temperatures that would kill most bacteria, and a few bacteria can actually grow at temperatures well below freezing. Earlier this year, he was involved in the recall of an intravenous heparin solution that was blamed for causing Pseudomonas fluorescens bloodstream infections in patients in four different states. It seemed that everything was under control, but now, three months after the recall, 19 patients in two other states develop the same P. Q Which bacterium would theoretically be more likely to grow at refrigerator temperatures: a human intestinal pathogen or a soilborne plant pathogen Many of these organisms have an optimum growth temperature of 50­60°C, about the temperature of water from a hot water tap. Such temperatures can also be reached in sunlit soil and in thermal waters such as hot springs. Endospores formed by thermophilic bacteria are unusually heat resistant and may survive the usual heat treatment given canned goods. Although elevated storage temperatures may cause surviving endospores to germinate and grow, thereby spoiling the food, these thermophilic bacteria are not considered a public health problem. Some microbes, members of the Archaea (page 5), have an optimum growth temperature of 80°C or higher. Most of these organisms live in hot springs associated with volcanic activity, and sulfur is usually important in their metabolic activity. The known record for bacterial growth and replication at high temperatures is about 121°C near deepsea hydrothermal vents. The immense pressure in the ocean depths prevents water from boiling even at temperatures well above 100°C. Nonetheless, some bacteria, called acidophiles, are remarkably tolerant of acidity. One type of chemoautotrophic bacteria, which is found in the drainage water from coal mines and oxidizes sulfur to form sulfuric acid, can survive at a pH 1. Molds and yeasts will grow over a greater pH range than bacteria will, but the optimum pH of molds and yeasts is generally below that of bacteria, usually about pH 5 to 6. When bacteria are cultured in the laboratory, they often produce acids that eventually interfere with their own growth. To neutralize the acids and maintain the proper pH, chemical buffers are included in the growth medium. The peptones and amino acids in some media act as buffers, and many media also contain phosphate salts. Phosphate salts have the advantage of exhibiting their buffering effect in the pH growth range of most bacteria. This is why a number of foods, such as sauerkraut, pickles, and Osmotic Pressure Microorganisms obtain almost all their nutrients in solution from the surrounding water. When a microbial cell is in a solution whose concentration of solutes is higher than in the cell (the environment is hypertonic to the cell), the cellular water passes out through the plasma membrane to the high solute concentration. Under these conditions, the solute concentration in the cell is equivalent to a solute concentration of 0. If the concentration of solutes such as NaCl is higher in the surrounding medium than in the cell (the environment is hypertonic), water tends to leave the cell. Thus, the addition of salts (or other solutes) to a solution, and the resulting increase in osmotic pressure, can be used to preserve foods. Salted fish, honey, and sweetened condensed milk are preserved largely by this mechanism; the high salt or sugar concentrations draw water out of any microbial cells that are present and thus prevent their growth. Some organisms, called extreme halophiles, have adapted so well to high salt concentrations that they actually require them for growth. Organisms from such saline waters as the Dead Sea often require nearly 30% salt, and the inoculating loop (a device for handling bacteria in the laboratory) used to transfer them must first be dipped into a saturated salt solution. More common are facultative halophiles, which do not require high salt concentrations but are able to grow at salt concentrations up to 2%, a concentration that inhibits the growth of many other organisms. For example, the concentration of agar (a complex polysaccharide isolated from marine algae) used to solidify microbial growth media is usually about 1. If markedly higher concentrations are used, the increased osmotic pressure can inhibit the growth of some bacteria. If the osmotic pressure is unusually low (the environment is hypotonic)-such as in distilled water, for example-water tends to enter the cell rather than leave it. Some microbes that have a relatively weak cell wall may be lysed by such treatment. Nitrogen, Sulfur, and Phosphorus In addition to carbon, microorganisms need other elements to synthesize cellular material. For example, protein synthesis requires considerable amounts of nitrogen as well as some sulfur. Nitrogen makes up about 14% of the dry weight of a bacterial cell, and sulfur and phosphorus together constitute about another 4%. Organisms use nitrogen primarily to form the amino group of the amino acids of proteins. Many bacteria meet this requirement by decomposing protein-containing material and reincorporating the amino acids into newly synthesized proteins and other nitrogen-containing compounds. Some important bacteria, including many of the photosynthesizing cyanobacteria (page 307), use gaseous nitrogen (N2) directly from the atmosphere. Some organisms that can use this method are freeliving, mostly in the soil, but others live cooperatively in symbiosis with the roots of legumes such as clover, soybeans, alfalfa, beans, and peas. The nitrogen fixed in the symbiosis is used by both the plant and the bacterium (see Chapter 27). Sulfur is used to synthesize sulfur-containing amino acids and vitamins such as thiamine and biotin. Phosphorus is essential for the synthesis of nucleic acids and the phospholipids of cell membranes. Potassium, magnesium, and calcium are also elements that microorganisms require, often as cofactors for enzymes (see Chapter 5, page 114). Trace Elements Microbes require very small amounts of other mineral elements, such as iron, copper, molybdenum, and zinc; these are referred to as trace elements. Although these elements are sometimes added to a laboratory medium, they are usually assumed to be naturally present in tap water and other components of media. Even most distilled waters contain adequate amounts, but tap water is sometimes specified to ensure that these trace minerals will be present in culture media. Oxygen We are accustomed to thinking of molecular oxygen (O2) as a necessity of life, but it is actually in a sense a poisonous gas. Chemical Requirements Carbon Besides water, one of the most important requirements for microbial growth is carbon. Carbon is the structural backbone of living matter; it is needed for all the organic compounds that make up a living cell. Chemoheterotrophs get most of their carbon from the source of their energy-organic materials such as proteins, carbohydrates, and lipids. Facultative Anaerobes Both aerobic and anaerobic growth; greater growth in presence of oxygen. Aerotolerant Anaerobes Only anaerobic growth; but growth continues in presence of oxygen.

Dogs and cats are also frequently infected with fungi that cause ringworm in children gastritis treatment probiotics discount protonix 40 mg without prescription. Ringworm of the fingernails or toenails is called tinea unguium gastritis leaky gut 20 mg protonix, or onychomycosis gastritis diet �?��� protonix 40 mg order on-line. The topical drugs available without prescription for tinea infections include miconazole and clotrimazole chronic gastritis reflux buy protonix australia. Topical allylamine preparations containing terbinafine or naftifine gastritis zdravlje buy cheapest protonix and protonix, as well as another allylamine, butenavine, are recommended and are now available without a prescription. An oral antibiotic, griseofulvin, is often useful in such infections because it can localize in keratinized tissue, such as skin, hair, or nails. When nails are infected, oral itraconazole and terbinafine are the drugs of choice, but treatment may require weeks, and both must be used with caution because of potential severe side effects. To find a control group, the health department asks each case to name up to two adults and two children who were in the pool at the same time but did not develop a rash. The health department obtains swabs from the rashes and has them inoculated onto nutrient agar and incubated at 35°C for 24 hours. Subcutaneous Mycoses Subcutaneous mycoses are more serious than cutaneous mycoses. Even when the skin is broken, cutaneous fungi do not seem to be able to penetrate past the stratum corneum, perhaps because they cannot obtain sufficient iron for growth in the epidermis and the dermis. Usually subcutaneous mycoses are caused by fungi that inhabit the soil, especially decaying vegetation, and penetrate the skin through a small wound that allows entry into subcutaneous tissues. In the United States, the most common disease of this type is sporotrichosis, caused by the dimorphic fungus Sporothrix schenkii. The fungus often enters the lymphatic system in the area and there forms similar lesions. The condition is seldom fatal and is effectively treated with itraconazole, or by ingesting a dilute solution of potassium iodide. Candidiasis the bacterial microbiota of the mucous membranes in the genitourinary tract and mouth usually suppress the growth of such fungi as Candida albicans. The ¯ ¯ morphology of these organisms is not always yeastlike but can exhibit the formation of pseudohyphae, long cells that resemble hyphae. Because the fungus is not affected by antibacterial drugs, it sometimes Based on the figure, what is the bacterium Notice the spherical chlamydoconidia (resting bodies formed from hyphal cells) and the smaller blastoconidia (asexual spores produced by budding) (see Chapter 12). On people who are obese or diabetic, the areas of the skin with more moisture tend to become infected with this fungus. If candidiasis becomes systemic, as can happen in immunosuppressed individuals, fulminating disease (one that appears suddenly and severely) and death can result. Several new treatments are now also available; for example, some of the new echinocandin class antifungals, such as micafungin and anidulafungin, are now approved for this use. Parasitic Infestation of the Skin Parasitic organisms such as some protozoa, helminths, and microscopic arthropods can infest the skin and cause disease conditions. Scabies Probably the first documented connection between a microscopic organism (330­450 m) and a disease in humans was scabies, which was described by an Italian physician in 1687. The burrows are often visible as slightly elevated, serpentine lines about 1 mm in width. However, scabies may appear as a variety of inflammatory skin lesions, many of them secondary infections from scratching. The mite is transmitted by intimate contact, including sexual contact, and is most often seen in family members, nursing home residents, and teenagers infected by children for whom they baby-sit. About 500,000 people seek treatment for scabies in the United States each year; in developing countries, it is even more prevalent. The mite lives about 25 days, but by that time eggs have hatched and produced a dozen or so progeny. Scabies is usually diagnosed by microscopic examination of skin scrapings and usually is treated by topical application of permethrin. Pediculosis (Lice) Infestations by lice, called pediculosis, have afflicted humans for thousands of years. Although usually associated in the public mind with poor sanitation, outbreaks of head lice among middle- and upper-class schoolchildren in the United States are common. Parents are usually appalled, but head lice are easily transferred by head-to-head contact, such as occurs among children who know each other well. The head louse, Pediculus humanus capitis, is not the same as the body louse, Pediculus humanus corporis. These are subspecies of Pediculus humanus that have adapted to different areas of the body. The victim is often unaware of these silent passengers until itching, which is a result of sensitization to louse saliva, develops several weeks later. During a life span of a little over a month, the female louse produces several eggs (nits) a day. As the hair grows (at the rate of about 1 cm a month), the attached nit moves away from the scalp. A point of interest is that in the United States, lice have become adapted to the cylindrical hair shafts found on whites. Twenty-five of the patients with rashes and none of the controls had used the inflatable. The inflatable is not watertight; during use, inflation is maintained with an air pump. The inflatable is used about 1 hour a day, 3 days a week, and stored next to the pool when not in use. It does this by gulping air and forcing it out the anus until it pops free, much like a champagne cork. Corneal abrasion; soft contact lenses may prevent removal of ameba by blinking Keratitis Contact with fresh water Topical propamidine isethionate or miconazole; corneal transplant or eye removal surgery may be required Treatments of head lice abound, recalling the medical adage that if there are many treatments for a condition, it is probably because none of them are really good. Nonprescription medications such as permethrin insecticide and pyrethrin insecticide are usually the first-choice treatment, but resistance has become common. Other topical preparations containing insecticides such as malathion and the more toxic lindane are also available (lindane is banned in some areas). This is a difficult, time-consuming procedure that has actually led to the appearance of professional removal services in some cities: expensive, but often worth the price to busy parents. Silver nitrate has been almost entirely replaced by antibiotics because of frequent coinfections by gonococci and sexually transmitted chlamydias, which silver nitrate is not effective against. In parts of the world where the cost of antibiotics is prohibitive, a dilute solution of povidoneiodine has proven effective. The epithelial cells covering the eye can be considered a continuation of the skin or mucosa. Many microbes can infect the eye, largely through the conjunctiva, the mucous membrane that lines the eyelids and covers the outer white surface of the eyeball. Inflammation of the Eye Membranes: Conjunctivitis Conjunctivitis is an inflammation of the conjunctiva, often called by the common name red eye, or pinkeye. Haemophilus influenzae is the most common bacterial cause; viral conjunctivitis is usually caused by adenoviruses. However, a broad group of bacterial and viral pathogens as well as allergies can also cause this condition. The popularity of contact lenses has been accompanied by an increased incidence of infections of the eye. This is especially true of the soft-lens varieties, which are often worn for extended periods. Among the bacterial pathogens that cause conjunctivitis are pseudomonads, which can cause serious eye damage. The most effective methods for disinfecting contact lenses involve applying heat; lenses that cannot be heated can be disinfected with hydrogen peroxide, which is then neutralized. Inclusion Conjunctivitis Chlamydial conjunctivitis, or inclusion conjunctivitis, is quite common today. It is caused by Chlamydia trachomatis, a bacterium that grows only as an obligate intracellular parasite. In infants, who acquire it in the birth canal, the condition tends to resolve spontaneously in a few weeks or months, but in rare cases it can lead to scarring of the cornea. Chlamydial conjunctivitis also appears to spread in the unchlorinated waters of swimming pools; in this context, it is called swimming pool conjunctivitis. Trachoma A serious eye infection, and probably the greatest single cause of blindness by an infectious disease, is trachoma-an ancient name derived from the Greek word for rough. It is caused by certain serotypes of Chlamydia trachomatis, but not the same ones that cause genital infections (see pages 770­775). In the arid parts of Africa and Asia, almost all children are infected early in their lives. Worldwide, there are probably 500 million active cases and 7 million blinded victims. Trachoma also occurs occasionally in the southwestern United States, especially among Native Americans. The disease is a conjunctivitis transmitted largely by hand contact or by sharing such personal objects as towels. Abrasion of the cornea, especially by the eyelashes, eventually causes scarring of the cornea and blindness. Trichiasis can be corrected surgically, a procedure shown in ancient Egyptian papyri. Secondary infections by other bacterial pathogens are also a factor in the disease. Antibiotics to eliminate chlamydia, especially oral azithromycin, are useful in treatment. Ophthalmia Neonatorum Ophthalmia neonatorum is a serious form of conjunctivitis caused by Neisseria gonorrhoeae, the cause of gonorrhea. Large amounts of pus are formed; if treatment is delayed, ulceration of the cornea will usually result. The disease is acquired as the infant passes through the birth canal, and infection carries a high risk of blindness. Early in the twentieth century, legislation required that the eyes of all newborn infants be treated 21-9 What is the common name of inclusion conjunctivitis The disease is an infection of the cornea, often resulting in deep ulcers, and that may be the most common cause of infectious blindness in the United States. Acanthamoeba Keratitis the first case of Acanthamoeba keratitis was reported in 1973 in a Texas rancher. Most recent cases have been associated with the wearing of contact lenses, although any cornea damaged by trauma or infection is susceptible. Contributing factors are inadequate, unsanitary, or faulty disinfecting procedures (only heat will reliably kill the cysts), homemade saline solutions, and wearing the contact lenses overnight or while swimming. In its early stages, the infection consists of only a mild inflammation, but later stages are often accompanied by severe pain. If started early, treatment with 2% chlorhexidine and propamidine isethionate eye drops or topical neomycin has been successful. Damage is often so severe as to require a corneal transplant or even removal of the eye. Diagnosis is confirmed by the presence of trophozoites and cysts in stained scrapings of the cornea. The eyelid has been pulled back to show the inflammatory nodules that are in contact with the cornea. The abrasion caused by this damages the cornea and makes it susceptible to secondary infections. Other Infectious Diseases of the Eye the diseases discussed here are characterized by inflammation of the cornea, which is called keratitis. In Africa and Asia, eye infections are mostly caused by fungi, such as Candida, Fusarium, and Aspergillus. Because the inflatable never completely dries, the bacteria probably grow inside while it is in storage. The bacteria leak out the seams and enter the body through minor abrasions, possibly obtained by contact with the inflatable. The one patient who had a rash on her legs but had not used the inflatable most likely acquired her rash from the tile. Pseudomonas dermatitis outbreaks usually occur as a result of low levels of water disinfectant in pools and hot tubs. In this case, the ability of Pseudomonas to grow on organic molecules inside the inflatable contributed to the outbreak. Guidelines for disinfecting pool equipment without damaging the equipment are being developed. A Different Kind of Public Health Campaign Traditionally, public health campaigns target the largest health threats one disease at a time. An unfortunate consequence of this approach is that certain serious infections with lower incidence rates never meet the criteria for major health campaigns. They disproportionately infect the poorest people living in the least developed areas. Main approaches include early diagnosis and treatment; zoonotic disease management; preventive chemotherapy; vector control and pesticide management; and improvement of sanitation and drinking water safety. It affects 18 million people in western and central Africa, the Middle East, and Latin America. Improved Sanitation and Hygiene Services Safe drinking water and improved sanitation systems can reduce prevalence of many diseases, including dracunculiasis, schistosomiasis, trachoma, Buruli ulcer, and yaws. Preventive Chemotherapy Pharmaceutical firms donate medication and share technology and data to develop new treatments. Grants from organizations such as the Bill and Melinda Gates Foundation fund development of portable testing devices, allowing for rapid diagnosis and immediate treatment.

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Starting in late 2016 gastritis and nausea 40 mg protonix buy amex, the Federal Drug Association banned triclosan from over-thecounter consumer washing products gastritis causes cheap protonix 40 mg with mastercard. The American Medical Association recommends using plain soap and water and proper handwashing techniques instead- Staphylococcus aureus gastric bypass diet protonix 20 mg order with mastercard. S taphylococcus aureus is a normal member of the human microbiome gastritis diet 4 life cheap protonix 20 mg without a prescription, found on the skin and in the nose gastritis diet ��� purchase protonix canada. The bacterium can switch from benign member of the skin community to a disease-causing pathogen if it gains entry to the body through a wound. Over the years, triclosan was also added to many household products, such as dishwashing detergent, toothpastes, and body washes. However, using these antimicrobial products daily seems to be a case of "too much of a good thing. Therefore, triclosan can be found in many areas of the body, these products and techniques remove microbes without the harmful unintended consequences associated with widespread triclosan use. Pine oil and tea tree oil have a broad spectrum of activity, including killing gramnegative bacteria and fungi. Halogens the halogens, particularly iodine and chlorine, are effective antimicrobial agents, both alone and as constituents of inorganic or organic compounds. It is active against all kinds of bacteria, many endospores, various fungi, and some viruses. Iodine impairs protein synthesis and alters cell membranes, apparently by forming complexes with amino acids and unsaturated fatty acids. Iodine is available as a tincture-that is, in solution in aqueous alcohol-and as an iodophor. An iodophor is a combination of iodine and an organic molecule, from which the iodine is released slowly. Iodophors have the antimicrobial activity of iodine, but they do not stain and are less irritating. Povidone is a surface-active iodophor that improves the wetting action and serves as a reservoir of free iodine. Many campers are familiar with using iodine for water treatment; it is even used to disinfect drinking water on the International Space Station. Chlorine (Cl2), as a gas or in combination with other chemicals, is another widely used disinfectant. Hypochlorous acid is the most effective form of chlorine because it is neutral in electrical charge and diffuses as rapidly as water through the cell wall. A liquid form of compressed chlorine gas is used extensively for disinfecting municipal drinking water, water in swimming pools, and sewage. This compound, once called chloride of lime, was used as early as 1825-long before the concept of a germ theory for disease-to soak hospital dressings in Paris hospitals. It was also the disinfectant Semmelweis used in the 1840s to control hospital infections during childbirth, as mentioned in Chapter 1, page 10. When the quality of drinking water is in question, household bleach can provide a rough equivalent of municipal chlorination. After two drops of bleach are added to a liter of water (four drops if the water is cloudy) and the mixture has sat for 30 minutes, the water is considered safe for drinking under emergency conditions. Chloramine is also used to sanitize eating utensils and foodmanufacturing equipment. Chloramine is a relatively stable compound that releases chlorine over long periods. Chloramine is less likely to react with organic compounds in the water than hypochlorite. Alcohol usually denatures protein, but it can also disrupt membranes and dissolve many lipids, including the lipid component of enveloped viruses. One advantage of alcohols is that they act and then evaporate rapidly, leaving no residue. When the skin is swabbed (degermed) before an injection, most of the microbial control activity comes from simply wiping away dirt and microorganisms, along with skin oils. They cause coagulation of a layer of protein under which bacteria continue to grow. The recommended optimum concentration of ethanol is 70%, but concentrations between 60% and 95% seem to kill as well (Table 7. Pure ethanol is less effective than aqueous solutions (ethanol mixed with water) because denaturation requires water. Isopropanol, often sold as rubbing alcohol, is slightly superior to ethanol as an antiseptic and disinfectant. Moreover, it is less volatile, less expensive, and more easily obtained than ethanol. Alcohol-based (about 62% alcohol) hand sanitizers such as Purell and Germ-X are very popular for use on hands that are not visibly soiled; the product should be rubbed over the surfaces of the hands and fingers until they are dry. Also, certain pathogens, such as the spore-forming Clostridium difficile and viruses that lack a lipid envelope, are comparatively resistant to alcohol-based hand sanitizers. Ethanol and isopropanol are often used to enhance the effectiveness of other chemical agents. For example, an aqueous solution of Zephiran (described on page 194) kills about 40% of the population of a test organism in 2 minutes, whereas a tincture of Zephiran kills about 85% in the same period. Heavy Metals and Their Compounds Several heavy metals, including silver, mercury, and copper, can be biocidal or antiseptic. Clear zones where bacterial growth has been inhibited are seen around the sombrero charm (pushed aside), the dime, and the penny. Q the coins used in this demonstration were minted many years ago; why were more contemporary coins not used Centuries ago, Egyptians found that putting silver coins in water barrels served to keep the water clean of unwanted organic growths. This action can be demonstrated by placing a coin or other clean piece of metal containing silver or copper on a culture on an inoculated Petri plate. When the metal ions combine with the sulfhydryl groups on cellular proteins, denaturation results. At one time, many states required that the eyes of newborns be treated with a few drops of silver nitrate to guard against an infection of the eyes called ophthalmia neonatorum, which the infants might have contracted as they passed through the birth canal. Silver-impregnated dressings that slowly release silver ions have proven especially useful against antibiotic-resistant bacteria. The enthusiasm for incorporating silver in all manner of consumer products is increasing. Among the newer products being sold are plastic food containers infused with silver nanoparticles, which are intended to keep food fresher, and silver-infused athletic shirts and socks, which are claimed to minimize odors. A combination of silver and the drug sulfadiazine, silversulfadiazine, is the most common formulation. Silver can also be incorporated into indwelling catheters, which are a common source of hospital infections, and in wound dressings. Surfacine is a relatively new antimicrobial for application to surfaces, either animate or inanimate. It contains water-insoluble silver iodide in a polymer carrier and is very persistent, lasting at least 13 days. Inorganic mercury compounds, such as mercuric chloride, have a long history of use as disinfectants. They have a very broad spectrum of activity; their effect is primarily bacteriostatic. However, their use is now limited because of their toxicity and ineffectiveness in organic matter. At present, the primary use of mercurials is to control mildew in exterior latex paints. Copper in the form of copper sulfate or other coppercontaining additives is used chiefly to destroy green algae (algicide) that grow in reservoirs, stock ponds, swimming pools, and fish tanks. If the water does not contain excessive organic matter, copper compounds are effective in concentrations of one part per million of water. To prevent mildew, copper compounds such as copper 8-hydroxyquinoline are sometimes included in paint. Mixtures based on copper ions (known as Bordeaux mixture) have long been used to control fungal diseases of plants. Copper and silver ions are used to disinfect drinking water and swimming pools and to control Legionella in hospital water supplies. Copper and silver electrodes release Ag + and Cu 2+ ions when an electric current is applied. These have been used for wound dressings and to prevent growth of biofilms on indwelling devices such as catheters. Long-term use of alcohol-based hand sanitizers often causes problems with skin dryness. A relatively new hand sanitizer, Xgel, does not contain alcohol but uses copper contained in a skin lotion formulation. Xgel may be more effective as an antimicrobial than alcohol-based hand sanitizers. The effect of trace amounts of zinc can be seen on weathered roofs of buildings downslope from galvanized (zinc-coated) fittings. The color of the roof is lighter where biological growth, mostly algae, is impeded. Zinc chloride is a common ingredient in mouthwashes, and zinc pyrithione is an ingredient in antidandruff shampoos. Surface-Active Agents Surface-active agents, or surfactants, can decrease surface tension among molecules of a liquid. Soaps and Detergents Soap has little value as an antiseptic, but it does have an important function in the mechanical removal of microbes through scrubbing. Soap breaks the oily film into tiny droplets, a process called emulsification, and the water and soap together lift up the emulsified oil and debris and float them away as the lather is washed off. Use soap and warm water (if possible), and rub hands together for 20 seconds (imagine singing "Happy Birthday" twice through). Then rinse, dry with a paper towel or air dryer, and try to use a paper towel to turn off the faucet. Acid-Anionic Sanitizers Acid-anionic sanitizers are very important in cleaning food-processing facilities, especially dairy utensils and equipment. Their sanitizing ability is related to the negatively charged portion (anion) of the molecule, which reacts with the plasma membrane. These sanitizers, which act on a wide spectrum of microbes, including troublesome thermoduric bacteria, are odorless, nontoxic, noncorrosive, and fast acting. Quaternary Ammonium Compounds (Quats) the most widely used surface-active agents are the cationic detergents, especially the quaternary ammonium compounds (quats). Their cleansing ability is related to the positively charged portion- the cation-of the molecule. They are strongly antimicrobial, colorless, odorless, tasteless, stable, easily diluted, and nontoxic, except at high concentrations. If your mouthwash bottle fills with foam when shaken, the mouthwash probably contains a quat. However, organic matter interferes with their activity, and quats are rapidly neutralized by soaps and anionic detergents. Anyone involved in medical applications of quats should remember that certain bacteria, such as some species of Pseudomonas, not only survive in quaternary ammonium compounds but actively grow in them. These microbes are resistant not only to the disinfectant solution but also to gauze and bandages moistened with it, because the fibers tend to neutralize the quats. Chemical Food Preservatives Chemical preservatives are frequently added to foods to retard spoilage. Among the more common additives are sodium benzoate, sorbic acid, and calcium propionate. The steeper the downward slope of the killing curve, the more effective the antiseptic. A 1% iodine in 70% ethanol solution is the most effective; soap and water are the least effective. Notice that a tincture of Zephiran is more effective than an aqueous solution of the same antiseptic. Sorbic acid- or its more soluble salt, potassium sorbate-and sodium benzoate prevent molds from growing in certain acidic foods, such as cheese and soft drinks. Calcium propionate, an effective fungistat used in bread, prevents the growth of surface molds and the Bacillus bacteria that produce the mucuslike secretion that cause ropy bread. Sodium nitrate and sodium nitrite are added to many meat products, such as ham, bacon, hot dogs, and sausage. The active ingredient is sodium nitrite, which certain bacteria in the meats can also produce from sodium nitrate by anaerobic respiration. The nitrite has two main functions: to preserve the pleasing red color of the meat by reacting with blood components in the meat, and to prevent the germination and growth of any botulism endospores that might be present. Nitrite selectively inhibits certain iron-containing enzymes of Clostridium botulinum. There has been some concern that the reaction of nitrites with amino acids can form certain carcinogenic products known as nitrosamines, and the amount of nitrites added to foods has generally been reduced in recent years for this reason. However, the use of nitrites continues because of their established value in preventing botulism. Because nitrosamines are formed in the body from other sources, the added risk posed by a limited use of nitrates and nitrites in meats is lower than was once thought.

Because of the very high incidence there diet for chronic gastritis patients discount 20 mg protonix otc, the disease is also sometimes called Valley Fever gastritis diet ������� order protonix with american express. The small area on the map in northeastern Utah indicates an outbreak in 2001 in which ten archeologists working on excavations at the Dinosaur National Monument were infected gastritis ranitidine 20 mg protonix sale. Q Why does the incidence of coccidioidomycosis increase after ecological disturbances gastritis vs heart attack buy cheap protonix online, such as earthquakes and construction Long classified as a protozoan gastritis zwieback cheap 40 mg protonix visa, this organism is now usually considered to be a fungus, but it has characteristics of both groups. Immunocompetent adults have few or no symptoms, but newly infected infants occasionally show symptoms of a lung infection. This population may also be the reservoir of the organism, which is not found in the environment, animals, or very often in healthy humans. Presumably, the loss of an effective immune defense allows the activation of a latent infection. Other groups that are very susceptible to this disease are people whose immunity is depressed because of cancer or who are receiving immunosuppressive drugs to minimize rejection of transplanted tissue. There, they form a thickwalled cyst in which spherical intracystic bodies successively divide as part of a sexual cycle. Eventually the cyst ruptures and releases them, and each body develops into a trophozoite. The trophozoite cells can reproduce asexually by fission, but they may also enter the encysted sexual stage. Blastomycosis (North American Blastomycosis) Blastomycosis is usually called North American blastomycosis to differentiate it from a similar South American blastomycosis. Approximately 100 cases are reported each year, although most infections are asymptomatic. Such diseases can be very dangerous, particularly invasive infections of pulmonary aspergillosis. As with most systemic fungal infections, there is only a limited arsenal of antifungal agents available; itraconazole and amphotericin B have proved the most useful. Q What other respiratory mycosis has a similar geographic *** Diseases in Focus 24. Cutaneous ulcers commonly appear when the yeast are disseminated in circulating monocytes. Compost piles are ideal sites for growth, and farmers and gardeners are most often exposed to infective amounts of these conidia. Similar pulmonary infections sometimes result when individuals are exposed to spores of other mold genera, such omestic and imported pet birds, as well as humans, are at risk for infection with and transmission of C. Avian infection, which has a prevalence of less than 5%, may increase to 100% under such circumstances. Unless treatment is continued for 45 days, infected birds arriving to distributors from breeders and from quarantine may shed C. A purified protein derivative test is negative; a cytological examination for cancer is also negative. A membrane, containing fibrin and dead human and bacterial cells, forms in the throat and can block the passage of air. The exotoxin inhibits protein synthesis, and heart, kidney, or nerve damage may result. Laboratory diagnosis is based on isolation of the bacteria and the appearance of growth on differential media. The upper respiratory system consists of the nose, pharynx, and associated structures, such as the middle ear and auditory tubes. Coarse hairs in the nose filter large particles from air entering the respiratory tract. The ciliated mucous membranes of the nose and throat trap airborne particles and remove them from the body. The lower respiratory system consists of the larynx, trachea, bronchial tubes, and alveoli. The ciliary escalator of the lower respiratory system helps prevent microorganisms from reaching the lungs. Earache, or otitis media, can occur as a complication of nose and throat infections. Bacterial causes include Streptococcus pneumoniae, nonencapsulated Haemophilus influenzae, Moraxella catarrhalis, and Streptococcus pyogenes. The normal microbiota of the nasal cavity and throat can include pathogenic microorganisms. Specific areas of the upper respiratory system can become infected to produce pharyngitis, laryngitis, tonsillitis, sinusitis, and epiglottitis. These infections may be caused by several bacteria and viruses, often in combination. The incidence of colds increases during cold weather, possibly because of increased interpersonal indoor contact or physiological changes. This infection is caused by group A beta-hemolytic streptococci, the group that consists of Streptococcus pyogenes. Symptoms of this infection are inflammation of the mucous membrane and fever; tonsillitis and otitis media may also occur. Many of the same microorganisms that infect the upper respiratory system also infect the lower respiratory system. The initial stage of pertussis resembles a cold and is called the catarrhal stage. The accumulation of mucus in the trachea and bronchi causes deep coughs characteristic of the paroxysmal (second) stage. A number of viruses can cause pneumonia as a complication of infections such as influenza. The etiologies are not usually identified in a clinical laboratory because of the difficulty in isolating and identifying viruses. Mycobacterium bovis causes bovine tuberculosis and can be transmitted to humans by unpasteurized milk. New foci of infection can develop when a caseous lesion ruptures and releases bacteria into blood or lymph vessels; this is called miliary tuberculosis. Chemotherapy usually involves three or four drugs taken for at least 6 months; multidrug-resistant M. Influenza is caused by Influenzavirus and is characterized by chills, fever, headache, and general muscular aches. Fungal spores are easily inhaled; they may germinate in the lower respiratory tract. Chlamydophila psittaci, the bacterium that causes psittacosis (ornithosis), is transmitted by contact with contaminated droppings and exudates of fowl. Chlamydophila pneumoniae causes pneumonia; it is transmitted from person to person. Histoplasma capsulatum causes a subclinical respiratory infection that only occasionally progresses to a severe, generalized disease. Inhaling the airborne arthroconidia of Coccidioides immitis can result in coccidioidomycosis. Melioidosis, caused by Burkholderia pseudomallei, is transmitted by inhalation, ingestion, or through puncture wounds. Opportunistic fungi can cause respiratory disease in immunosuppressed hosts, especially when large numbers of spores are inhaled. Briefly describe the procedures and positive results of the tuberculin test and what is indicated by a positive test. Identify the bacteria involved in respiratory infections using the following laboratory test results: Gram-positive cocci Catalase-positive: a. List the causative agent, symptoms, and treatment for four viral diseases of the respiratory system. Separate the diseases according to whether they infect the upper or lower respiratory system. A patient has fever, difficulty breathing, chest pains, fluid in the alveoli, and a positive tuberculin skin test. No bacterial pathogen can be isolated from the sputum of a patient with pneumonia. Match the following choices to the culture descriptions in questions 3 through 6: a. Under what conditions can the saprophytes Aspergillus and Rhizopus cause infections List the causative agent, mode of transmission, and endemic area for the diseases histoplasmosis, coccidioidomycosis, blastomycosis, and Pneumocystis pneumonia. In San Francisco, ten animal health care technicians developed pneumonia 2 weeks after 130 goats were moved to the animal shelter where they worked. Explain why it would be impractical to include cold and influenza vaccinations in the required childhood vaccinations. In August, a 24-year-old man from Virginia developed difficulty breathing and bilateral lobe infiltrates 2 months after driving through California. During initial evaluation, typical pneumonia was suspected, and he was treated with antibiotics. In October, a laryngeal mass was detected, and laryngeal cancer was suspected; treatment with steroids and bronchodilators did not result in improvement. Microbial Diseases of the Digestive System icrobial diseases of the digestive system are second only to respiratory diseases as causes of illness in the United States. Most such diseases result from ingesting food or water contaminated with pathogenic microorganisms or their toxins. These pathogens usually enter the food or water supply after being shed in the feces of people or animals infected with them. Therefore, microbial diseases of the digestive system are typically transmitted by a fecal­oral cycle. This cycle is interrupted by effective sanitation practices in food production and handling. There is also an increasing awareness of the need for new tests that will rapidly and reliably detect pathogens in foods (a perishable commodity). As more of our food products-especially fruits and vegetables-are grown in countries with poor sanitation standards, outbreaks of foodborne disease from imported pathogens are expected to increase. The bacteria (shown in the photo) that make these toxins are called Shiga toxin-producing E. M 25 Escherichia coli bacteria are essential members of the human microbiome unless they produce a toxin, such as the Shiga toxin produced by E. In the Clinic As the county public health nurse, you were contacted regarding a woman who had acute gastroenteritis after dining at a local restaurant with friends. You interviewed the diners and confirmed that three of the seven in the party had consumed New England clam chowder. Within 1 to 4 hours after consumption, the three had onset of nausea and vomiting lasting 24 to 48 hours. The restaurant had kept the clam chowder at 39°C for the lunch and dinner service. Hint: Make a list of the foodborne diseases covered in this chapter to match to this case. The purpose of the digestive system is to digest foods- that is, to break them down into small molecules that can be taken up and used by body cells. In a process called absorption, these end-products of digestion pass from the small intestine into the blood or lymph for distribution to body cells. Then the food moves through the large intestine, where water and any remaining nutrients are absorbed from it. The resulting undigested solids, called feces, are eliminated from the body through the anus. Intestinal gas, or flatus, is a mixture of nitrogen from swallowed air and microbially produced carbon dioxide, hydrogen, and methane. Throughout life, the intestinal mucosa continues to be challenged by the antigens of the intestinal microbiota and ingested. As a consequence, an estimated 70% of the immune system is located in the intestinal tract, especially the small intestine. Because of the hydrochloric acid produced by the stomach and the rapid movement of food through the small intestine, these organs house relatively few microorganisms. By contrast, the large intestine has enormous microbial populations, exceeding 100 billion bacteria per gram of feces. Most of these bacteria assist in the enzymatic breakdown of foods, especially many polysaccharides that would otherwise be indigestible. About 10 bacterial species per gram of contents are found in the esophagus, while over 1000 bacterial species per gram reside in the large intestine. Current research indicates our resident microbes may have as much to do with this sorting out of good bacteria from the bad as our own immune system does. We are born with an underdeveloped immune system and very few microbes populating our bodies. This process is enhanced by the fact that the beneficial bacteria then make compounds that hurt pathogens while leaving their and our cells intact. This antibody class exerts anti-inflammatory effects and creates a barrier in the mucosa that prevents many pathogens from attaching to the epithelial cells there. These compounds bind to the more negatively charged membranes of bacteria and lyse them, leaving the membranes of our own cells intact. The short-chain fatty acids produced by Lactobacillus and Bacteroides cause host cells to make another antimicrobial peptide, cathelicidin. An important factor in this defense is the high acid content of the stomach, which eliminates many potentially harmful ingested microbes. The small intestine also contains important antimicrobial defenses, most significantly, millions of specialized, granulefilled cells called Paneth cells. These are capable of phagocytizing bacteria, and they also produce antibacterial proteins called defensins (see antimicrobial peptides, page 469) and the antibacterial enzyme lysozyme.

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