Skin and Eye Infections Cases and Homework

________________ is caused by a Chlamydia species and is the leading cause of preventable microbial blindness. (a) Acanthamoeba keratitis (b) Trachoma (c) Viral keratitis (d) River blindness

B -- Trachoma

Which of the following primary skin lesions is a raised lesion that contains pus and is found below the skin surface? (a) Vesicle (b) Pustule (C) Papule (d) Bulla

B -- pustule

Scott is excited about starting college in about a month. He's looking forward to living on his own for the first time, meeting new friends, and taking college courses. However, he's also a little apprehensive about becoming part of this new community, full of new people who don't know him. He's particularly self-conscious about the acne on his face and neck. He always had a few pimples here and there, but over the last couple of months, his acne has gotten much more severe. He's been washing his face a lot, but still the acne just seems to be getting worse. Scott tells his mother that he's scared to start college looking this way. Although his mother assures him that it's not as bad as he thinks, she makes an appointment for Scott to see a dermatologist. At the doctor's office, Scott learns that he is not alone. Dr. Smith tells him that it is estimated that more than 80% of teenagers suffer from acne. Scott is happy to learn that although it may seem like a hopeless situation, there are several options available to help treat his acne. Dr. Smith explains to Scott that his acne is caused by a bacterium known as Propionibacterium acnes. It's the interaction between this bacterium and Scott's immune system that is leading to his acne. 1. The name Propionibacterium is derived from the fact that the organism produces propionic acid during fermentative metabolism. Which of the following statements about fermentative metabolism is true? (a) Fermentation produces significantly less ATP than aerobic respiration; however it generates NAD+, which can be used in glycolysis. (b) All fermentative organisms have the ability to perform ethanol fermentation. (c) Fermentation does not yield any ATP for the cell. (d) Fermentation is unfavorable because the production of acidic end-products provides an unfavorable environment for the organism's growth. 2. Scott is a little concerned when Dr. Smith tells him that a bacterium is in part responsible for his acne. Dr. Smith explains that bacteria are a normal part of a healthy functioning immune system and that they actually have important roles in our normal physiology. The problem in Scott's case is that things are a little out of balance. Hormonal changes are causing Scott's body to produce more sebum than is needed. Part of the reason for Scott's acne is the overproduction of sebum. Scott's initial instinct is that shutting down production of sebum would be the quickest route to eliminating his acne; however, sebum actually plays an important role in maintaining the skin as a first line of defense against pathogens. Which of the following best describes the role of sebum as a component of the first line of defense? Select all that apply. (a) Sebum creates an anaerobic environment, thereby preventing the growth of pathogenic organisms. (b) Sebum forms a protective layer over the skin. (c) Sebum contains enzymes that inhibit the growth of pathogens. (d) Sebum helps to keep the pH of the skin low, which inhibits the growth of microorganisms. 3. Dr. Smith continues to explain to Scott that the overproduction of sebum is just half of the equation. The excess sebum is not only clogging his pores, but also serving as a food source for P. acnes. This increases the growth of the bacteria, which in turn leads to inflammation. The acne on Scott's face and neck is a physical manifestation of this inflammation. Acne is the result of the inflammatory response. In this case, the inflammation is resulting in acne that is very painful (physically and emotionally) for Scott. However, inflammation is a critical component of a normal immune response. What are the main functions of the inflammatory response? Select all that apply. (a) producing antibodies, which can target and eliminate the invading organism (b) generating an increase of body temperature to inhibit the growth of the invading organism (c) destroying and eliminating the invading pathogen (d) "walling off" the site of injury or infection (e) repairing tissue damage resulting from inflammation 4. Skipped 5. Research has indicated that during the inflammatory response to P. acnes, both the classical and the alternative complement pathways are activated. Which of the following are outcomes of activating complement pathways? Select all that apply. (a) opsonization (b) generation of antibodies against P. acnes (c) activation of T cytotoxic cells (d) cytolysis (e) inflammation 6. Dr. Smith assures Scott that although inflammation may sound scary, there are several possible options for treating Scott's moderate acne. Which of the following would be the most appropriate for Scott's case? (a) topical application of salicylic acid (b) Clear Light, a nonchemical, light-based system (c) an oral antibiotic such as erythromycin (d) topical treatment with a product containing benzoyl peroxide (e) eliminating the intake of fatty foods (f) a prescription for Accutane 7. Dr. Smith prescribes oral erythromycin for Scott. She also recommends that he consider using an over-the-counter gel or cream containing benzoyl peroxide. Although this regimen should be effective at treating Scott's acne, there are some possible side effects. Which of the following are possible side effects of Scott's treatment? Select all that apply. (a) gastrointestinal problems resulting from a reduction/elimination of normal intestinal flora (b) selection of antibiotic-resistant strains of bacteria (c) excessive drying of the skin (d) immunosuppression due to prolonged use of oral antibiotics (e) inflammatory bowel disease

1. A -- Fermentation produces significantly less ATP than aerobic respiration; however it generates NAD+, which can be used in glycolysis. 2. B -- Sebum forms a protective layer over the skin. D -- Sebum helps to keep the pH of the skin low, which inhibits the growth of microorganisms. 3. C -- destroying and eliminating the invading pathogen D -- "walling off" the site of injury or infection E -- repairing tissue damage resulting from inflammation 5. A -- opsonization E -- cytolysis E -- inflammation 6. B -- Clear Light, a nonchemical, light-based system C -- an oral antibiotic such as erythromycin D -- topical treatment with a product containing benzoyl peroxide 7. A -- gastrointestinal problems resulting from a reduction/elimination of normal intestinal flora C -- excessive drying of the skin

A couple in their early forties have twin two-year-old girls, Elisa and Elizabeth, as well as a five-year-old daughter, Eowin. The twins attended daycare, and all children were current in their vaccinations. Both parents had standard vaccinations as children. One day, Elizabeth seemed a little bit under the weather. By the next day, she was complaining that the inside of her mouth hurt. Elisa had a bit of a fever and was crabby. It was the weekend, so the girls were not in daycare for a few days. No one was ill enough to take to the pediatrician, and the girls seemed fine a few days later. Over the weekend, their mother noticed a maculopapular rash on her hands. She was prone to sensitive-skin conditions, and she was extremely sensitive to poison ivy. When the twins were born, she had experienced severely itchy feet and had to seek help from a dermatologist to resolve the problem (dyshidrosis). The oldest daughter did not appear to exhibit any symptoms and neither did the father. By early the following week, a health notice was posted at the daycare to report that cases that sounded similar to what the family was experiencing were documented in some of the other children attending the daycare. 1. Which of the following should be excluded from the differential diagnosis (DDx)? Select all that apply. (a) Measles (b) Smallpox (c) Hand, foot, and mouth disease (d) Enterovirus infection (e) Rubella (f) Chickenpox 2. In the prior question (Part A) you were asked to eliminate certain diseases from the DDx listing. Here, you'll explore features of the listed diseases to support or refute their inclusion in the DDx. Sort the features as they apply to the disease. - Measles -Smallpox - Chickenpox - Rubella - Hand, foot, and mouth disease (a) Commonly spread through daycare facilities (b) Eradicated (c) Vaccine preventable (d) Associated with enterovirus 71 (e) Produces a vesicular rash (f) Produces a maculopapular rash 3. Which of the following infections best fits the described signs and symptoms? (a) Fifth disease (b) Hand, foot, and mouth disease (c) Oral herpes (d) Roseola 4. Which etiological agent is the most likely disease candidate for this case study? (a) Clostridium perfringens (b) Coxsackievirus A16 (c) Leishmania (d) Candida albicans 5. How can the spread of this infection be halted? Select all that apply. (a) Treatment of infected individuals with a broad-spectrum antibacterial drug (b) Fomite disinfection (c) Vaccination of susceptible individuals (d) Keep infected children home (e) General hygiene practices

1. A -- Measles, B -- Smallpox, E -- Rubella, F -- Chickenpox 2. Measles: C -- vaccine preventable, F -- Produces a maculopapular rash Smallpox: B -- eradicated, C -- vaccine preventable, E -- produces a vesicular rash Chickenpox: C -- vaccine preventable, E -- produces a vesicular rash Rubella: C -- vaccine preventable, F -- produces a maculopapular rash Hand, foot, and mouth disease: A -- commonly spread through daycare facilities, D -- associated with enterovirus 71, E -- produces a maculopapular rash 3. B -- Hand, foot, and mouth disease 4. B -- Coxsackievirus A16 5. B -- fomite disinfection, D -- keep infected children home, E -- general hygiene practice

A mother brings her three-year-old daughter to her pediatric office stating that the girl has had fever and chills for three days. The girl also has a large, intensely red patch with a distinct margin on her leg and a nearby swollen lymph node. When the health care provider touches the area, it is firm and warm, and the girl screams in pain. Based on these observations, the provider makes a presumptive diagnosis and begins treatment. 1. Based on the observations given, what is the probable diagnosis made by the health care provider? (a) erysipelas (b) impetigo (c) folliculitis (d) cellulitis 2. Infections with these symptoms are generally caused by which of the following pathogens? (a) Staphylococcus epidermidis (b) Streptococcus pyogenes (c) Staphylococcus aureus (d) Propionibacterium acnes 3. What is one of the virulence factors associated with the causative agent for this infection? (a) exoenzyme S (b) protein A (c) erythrogenic toxin (d) lipid A 4. What should the course of treatments for this infection entail? (a) topical antibiotics (b) debridement (c) oral antibiotics (d) aspiration 5. A chief concern of the health care provider with an infection such as this one would be which of the following? (a) the pain associated with the swollen lymph node (b) the accumulation of scar tissue due to the infection (c) the development of scalded skin syndrome (d) the bacteria spreading to the blood (bacteremia) and damaging the heart or the kidneys

1. A -- erysipelas 2. B -- Streptococcus pyogenes 3. C -- erythrogenic toxin 4. C -- oral antibiotics 5. D -- the bacteria spreading to the blood (bacteremia) and damaging the heart or the kidneys

The Davises were excited about their newborn twin boys and couldn't wait to take them to see Mr. Davis's father. Grandfather Davis was excited to see his first grandsons as well and thought their visit might help take his mind off the pain of his shingles, which had suddenly appeared only days before. 1. Which virus is responsible for Grandfather Davis's shingles? (a) varicella-zoster virus (b) orthopoxvirus (c) papillomavirus (d)Epstein-Barr virus 2. Which nucleic acid is part of the varicella-zoster virion? (a) dsRNA (b) ssRNA (c) dsDNA (d) ssDNA 3. Is Grandfather Davis contagious? (a) No. The twins would not develop chicken pox after their visit with Grandfather Davis. (b) Yes. The twins would probably develop chicken pox two weeks after their visit with Grandfather Davis. (c) No. The twins would probably develop measles two weeks after their visit with Grandfather Davis. (d) Yes. The twins would probably develop Reye's syndrome after their visit with Grandfather Davis. 4. What is the recommended schedule for the first chicken pox vaccine in infants? (a) 2 days of age (b) 6 months of age (c) 12 months of age (d) 5 years of age 5. What type of vaccine would be used to vaccinate the twins? (a) attenuated virus vaccine (b) inactivated virus vaccine (c) subunit vaccine (d) genetically engineered vaccine

1. A -- varicella-zoster virus 2. C -- dsDNA 3. B -- Yes. The twins would probably develop chicken pox two weeks after their visit with Grandfather Davis. 4. C -- 12 months of age 5. A -- attenuated virus vaccine

A 24-year old female automotive technician presents herself at the doctor's office. She complains of fever and of pain in her left hand. On physical examination, the patient had a deep wound on her left palm that was oozing pus. She had purplish, red streaks running up her left arm. She had enlarged lymph nodes at the elbow and under her arm. The patient's skin was warm and dry. In her history, the patient had punctured her left palm with sharp metal from the undercarriage of a "real cherry" 1977 Malibu about a week earlier. She said the wound had bled for a few minutes and she thought that she had washed it "real good" with soap and water. She had covered the wound with a large "band-aid" and gone back to work. She developed a fever about three days later. For the past couple of days, she "did not feel so good" and had vomiting and diarrhea. 1. What type of infection do you believe she has in this hand? (a) Streptococcus pyogenes (b) Staphylococcus aureus (c) Clostridium (d) Pseudomonas (e) Pasteurella multocida 2. From complaint and physical examination, which of the symptoms lead you to your choice of agent? (a) the fever and pain in the hand (b) the fever, wound with oozing pus and enlarged lymph nodes (c) the lymph nodes and red streaks (d) the warm dry skin (e) the pain, red streaks and enlarged lymph nodes 3. From the history, which of the information confirmed your choice? (a) The wound had bled for a while. (b) The wound was cleaned with soap and water. (c) The wound had been covered and had perhaps become anaerobic. (d) She had diarrhea and vomiting. (e) The cut was from a rusting car frame. 4. Which of the following is most likely to follow this infection? (a) gangrene and amputation (b) toxic shock syndrome (c) muscle spasms (d) neurological disfunction of the hand (e) arthritis

1. B -- Staphylococcus aureus 2. B -- the fever, would with oozing pus and enlarged lymph nodes 3. D -- She had diarrhea and vomiting. 4. B -- toxic shock syndrome

___________ is caused by a Gram-positive resident, Propionibacterium, which uses sebum as a nutrition source. (a) Acne (b) Cellulitis (c) Necrotizing fasciitis (d) Impetigo

A -- Acne

In the 1970s, archeologists unearthed a vast cemetery in the Atacama Desert of Chile. Because the Atacama is the driest desert on Earth, bodies over 800 years old were better preserved than might be expected. Some facial and brain tissues were mummified. The skulls of four women appeared as if the bone had been eaten, though it was obvious to the archeologists that the women had lived with the condition and died from other causes. It wasn't until in 2009 that scientists were able to solve the mystery of these skulls. Genetic analysis of tissue samples revealed that a flagellated protozoan had moved from facial lesions to the women's skulls, slowly eating them away over a 20-year period. 1. Which protozoan species is most likely the causative agent for this infection? (a) Trypanosoma brucei gambiense (b) Plasmodium vivax (c) Leishmania braziliensis (d) Trypanosoma cruzi 2. What disease name is used to refer to infections with these symptoms? (a) visceral leishmaniasis (b) cutaneous leishmaniasis (c) lymphocutaneous sporotrichosis (d) mucocutaneous leishmaniasis 3. How is this disease transmitted? (a) tsetse fly bite during blood meal (b) kissing (riduvid) bug feeding (c) sand fly bite during blood meal (d) Aedes mosquito bite during blood meal 4. This disease is most prevalent in which areas of the world? (a) South America (b) North America (c) Middle East (d) Asia 5. What would be the best treatment for this disease? (a) amphotericin B (b) erythromycin (c) terbinafine (d) acyclovir

1. C -- Leishmania braziliensis 2. D -- mucocutaneous leishmaniasis 3. C -- sand fly bite during blood meal 4. A -- South America 5. A -- amphotericin B

You are the school nurse at Willowdale Elementary. This morning Ms. Matthew, one of the first-grade teachers, brings a little girl named Keisha to your office. Her right eye is swollen and bloodshot. The lining of her lower lid is bright red. There is a thick yellow discharge in the corner of the eye. 1. What is the most like diagnosis, and what is the etiology (the cause or origin of the disease)? 2. What sign leads you to believe that the infection is bacterial in origin? 3. What is the treatment for this condition? Elaborate. Is the condition communicable? 4. What are some of the eye's natural defenses that help to prevent infections? 5. Are there steps the teacher should take to prevent the spread of this infection in the classroom? If so, discuss them.

1. Conjunctivitis. 2. The yellow discharge from the eye. 3. The treatment would consist of an antibiotic eye drop. Yes, the condition is communicable. 4. An enzyme is tears, lysozyme and the conjunctiva of the eye. 5. Yes, she should disinfect commonly touched surfaces so that children do not pick up the bacteria on their hands and touch their face/eyes.

Ten-year-old Rudy has several large warts on the fingers of his right hand. They do not hurt, but their unsightly appearance causes him to shy away from people. He is afraid to shake hands, or to play with other children out of fear that he may transfer the warts to them. Initially, his mother tells him not to worry about them, but Rudy cannot help feeling self-conscious. Furthermore, Rudy fears that the warts may somehow spread on his own body. After consulting with a physician, his mother decides to have the warts surgically removed. 1. What causes warts? (a) herpes virus (b) Epstein-Barr virus (c) handling frogs and toads (d) papillomavirus 2. Is it possible for Rudy's warts to spread to other areas of his body? (a) No. You have to handle frogs to get or spread warts. (b) Yes. Papillomaviruses are spread by direct contact. (c) Yes, especially if he undergoes laser treatments. (d) No. The virus is inactivated below 35 degrees Celsius. 3. What type of cancer is more likely to develop in people who have had papillomavirus infections? (a) leukemia (b) cancer of the tonsils (c) lung cancer (d) colon cancer 4. Which of the following is NOT an accepted treatment for warts? (a) "freezing" the wart with liquid nitrogen (b) daily application of salicylic acid (c) covering the wart with a piece of duct tape for several weeks (d) daily application of tincture of iodine to the wart surface

1. D -- papillomavirus 2. B -- Yes. Papillomaviruses are spread by direct contact. 3. B -- cancer of the tonsils 4. D -- daily application of tincture of iodine to the wart surface

A 62-year old diabetic man presents in the emergency room with a swollen left leg with areas of blanching and blue mottling. A "foul odor" is coming from a dressed wound. The physicians remove the dressing and a brownish fluid is seeping from a wounded area. The fluid contains what appear to be small bits of the tissue. No pus appears to be present. The wound has a strong "rotten" odor. Five days earlier, while at his work as a farmer, he caught the leg in his manure spreader, sustaining a deep, crushing, grossly dirty injury. His wife cleaned the wound as well as she could with soap and water, dressed it with clean gauze, and wrapped it tightly with an elastic bandage to stop the bleeding. The second day they redressed the wound and applied triple antibiotic ointment. The patient treated his pain with ibuprofen (Advil). He reported the pain was not very bad for the first 72 hours. In the past 24 hours, the leg swelled and the mottling began to appear. A foul odor and severe pain accompanied the swelling. His wife convinced him to come to the emergency room even though they did not have medical insurance. 1. What is your diagnosis in this case? 2. How should this wound be treated? 3. Is this a life-threatening condition? 4. Is it likely that the patient's diabetes contributed to the problem as presented?

1. Gas gangrene 2. Remove any dead and infected tissue. Amputation may be necessary. Then treat with antibiotics to control toxins. 3. Yes, if left untreated. A person can die from the toxin produced within 1-5 days without treatment. 4. Yes, diabetic patients have more risk due to the poorer circulation in the injured limb.

Kate, your sister-in-law, is about to undergo fertility treatments. Her doctor insists that she receive the rubella vaccination, and then wait several weeks before beginning the actual fertility regimen. Kate calls you and wants to know why she has to do this. You ask her if she is able to produce evidence of vaccination for rubella (also known as German measles). She says no; her family had a house fire a few years ago and all those records were lost. "But I had German measles when I was in second grade!" she says. "I remember I was really sick and missed almost a month of school." You suggest that she follow her doctor's advice and get the immunization. 1. Why would a fertility specialist recommend the rubella vaccine? Why does he suggest a waiting period after vaccination and before conceiving? 2. When do most children in the United States receive their rubella immunization? 3. Kate suggests that she had rubella in second grade, but the disease she described doesn't sound like rubella to you. Why not?

1. Rubella can cause birth defects such as miscarriage, deafness, blindness, or nervous system damage if contacted during pregnancy. The vaccine prevents you from contracting the disease. The waiting period is suggested to ensure that no complications, if any, from the vaccine affect the mother or child. 2. Most children get the vaccine shortly after they turn 1 (around 12-15 months of age). A booster shot is administered typically before a child starts school, so around 4-6 years old. Then again at around 10 years old. 3. The time frame she gave for the illness and the symptoms described were too strong to be Rubella. Rubella subsides quickly (within a few days) and has mild symptoms (mild rash and low fever). The illness Kate described sounds more like measles which can last a few months with strong symptoms.

A woman brings her 6-month-old son to the pediatrician. You are following the doctor as part of your physician's assistant training. Before you enter the examining room the physician pulls the chart off the door and hands it to you. The nurse has written on the chart that the chief complaint is a group of lesions on the child's back. You enter the room and greet the mother. A toddler girl is leaning over to play with the baby in his carrier on the floor. The baby is giggling and appears healthy. You notice on the chart that the baby was breast-fed from birth through his fourth month. Mom explains that the spots on the baby's back just popped up two days ago and that the baby hasn't had a fever and seems well. She lifts the baby up and you examine the lesions - a group of about seven to eight blisterlike lesions localized to the left of the baby's spine. They have clear fluid in them. The physician says the lesions are diagnostic. 1. What are the lesions diagnostic of? Explain how you decided. 2. Although this particular condition is somewhat unusual in babies, the lesions indicate that the child must have experienced a common childhood illness earlier. Which one? 3. The mother says that, to her knowledge, the baby has not had this common childhood illness, but that his 3-year-old sister had it four months ago, when the baby was 2 months old. Explain the link between the girl's illness and the baby's condition. 4. What factors probably influenced the fact that the baby did not have symptomatic illness when the baby was 2 months old. Explain the link between the girl's illness and the baby's condition. 5. What factors probably influenced the fact that the baby did not have symptomatic illness when his sister was experiencing it? What factors led to the eruption of lesions now? 6. Is this a dangerous condition? Why or why not?

1. Shingles. There is a band of blister along the left of the baby's spine and the spots in the baby's mouth could be a rash in a nerve-rich area. 2. Chickenpox 3. The baby had passive immunity from the mother but still contracted the herpes zoster virus and was asymptomatic. 4. The baby received antibodies from the mother's breast milk. 5. The baby did not experience symptoms before because of the passive immunity. However, the virus has now reactivated to cause the lesions and the shingles. 6. No, as long as the condition is not congenital.

A 58-year old lawyer presents in the emergency room with headache, irritability, generalized muscle pain and uncontrollable back spasms. He has become very restless and worried because he has had the back spasms all through his court case that afternoon and they became extremely painful. In his history, the lawyer states that he has a very busy practice. He is on medication for high blood pressure (beta blocker) and has mild asthma. He injured himself about 10 days earlier, puncturing his left arm with a nail from an old barn he is tearing. The wound has produced moderate quantities of pus, but he has been keeping it clean. When asked, he did not remember having a tetanus shot since he was a kid. The wound was sampled for microscopic examination and culture. The back appears to have very tight contractions and spasms. The patient is in obvious agonizing pain. 1. What is your diagnosis here? 2. What is the proper treatment of this problem? 3. How could this have been prevented?

1. Tetanus 2. Td vaccine, tetanus immune globin debridement, muscle relaxer for any muscle spasms, and a course of antibiotics. 3. A tetanus vaccine routinely every 10 years.

In the late winter of 1988, pediatricians in big cities around the country started reporting large increases in the numbers of patients they saw with diffuse red rashes and high fevers (greater than 101 °F). The rash, usually extending downward from the hairline to the rest of the body, began after a two-week incubation period. The spots were often so close together that the entire involved area appeared red. Sometimes the skin in such an area peeled after a few days. The rash lasted five to six days. Many of the children also suffered from diarrhea. The age group most affected was preschoolers. This was a change in epidemiology (the branch of medicine that deals with the study of the causes, distribution, and control of disease in populations) for this infection, as previously the disease most often struck school-age children. A vaccine had been introduced for this disease in 1963, and since then only 5000-6000 cases a year had been reported in the United States. In 1989, 18,193 cases were reported. In 1990 the epidemic (an outbreak of a contagious disease that spreads rapidly and widely; incidence of disease above normal levels) peaked with almost 28,000 cases reported in the United States. Since then the incidence in this country has fallen rapidly and is again in the range of 5000-6000 cases a year. 1. What was this resurgent infection? 2. What are some possible reasons for the epidemic in 1989-1991? 3. What is herd immunity? Discuss it in relation to this outbreak. 4. What is the schedule for vaccination for this infection in this United States? 5. Are serious sequelae associated with this infection? If so, what are they?

1. The infection is the measles. 2. There were probably low vaccination rates. Another possible reason would be that the bacteria became immune the vaccine. 3. Herd immunity is when at high proportion of members in the community have immunity against the illness (such as via a vaccination). This is relates the outbreak because it is likely the community had low vaccination rates which made herd immunity decrease in the community. 4. Most children get the vaccine at 12-15 months and again before they start school at 4-6 years old. 5. Yes, a person could go into a coma which can be fatal.

A woman is brought to the emergency department where you are working triage. She has an extremely swollen right lower leg. You see what appears to be an old surgical wound in the mid-calf, with rough scar tissue surrounded by purplish-red skin. She is in a lot of pain and her husband speaks for her. He tells you that three weeks ago she had a group of moles removed from that area. It had appeared to heal initially, but three days ago the incision area started looking bigger rather than smaller. She did not return to the physician, hoping the condition would resolve itself. In the past three days the area has begun to swell and become very hot. You call the attending physician immediately because you know that this is a serious condition. The patient is sent straight to surgery where the wound is debrided. Gram-positive cocci growing in chains are recovered from the wound. She is transferred to intensive care and put on high-dose intravenous antibiotics for the next 18 hours, but the next evening her leg is amputated below the knee. She remains in the hospital for two months following surgery and requires long-term antibiotic therapy and multiple skin grafts on her upper leg. 1. What condition did this patient have? What features suggest that it is not Clostridium perfringens gangrene? 2. Why was amputation the best solution for the infection in this case? 3. How is the bacterium transmitted? 4. It seems like we've heard a lot more about this condition in the past few years. Is this just media hype or are more cases occurring? Explain.

1. The women likely has Staphylococcus aureus which is a flesh eating microorganism. It is not Clostridium perfringens because the organism is not rod shaped. Also, Clostridium perfringens is most commonly found in the intestines, not the leg. 2. Many S. aureus are now resistant to many antibiotics. 3. S. aureus are found on the skin of health individuals but can cause problems when there is a cut and a break in the skin's natural defenses. 4. S. aureus is commonly found on the skin and the increase in antimicrobial resistance is causing more cases to pop up as it becomes resistant to common antibiotic treatments.

Which of the following diseases is incorrectly matched with its characteristics? (a) Hand, foot, and mouth disease: mild disease that is mainly caused by coxsackievirus A16 and enterovirus 71 (b) Fifth disease: caused by a parvovirus and presents with a red facial rash (c) Roseola: rare childhood infection that tends to present without a fever (d) Rubella: also known as German measles and presents with a rash and swollen lymph nodes

C -- Roseola: rare childhood infection that tends to present without a fever

Which of the following is not a Staphylococcus aureus virulence factor? (a) Coagulase (b) A polysaccharide capsule (c) Exfoliative toxin (d) M-protein

D -- M-protein