Wound Infection in Automotive Technician Case Study
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.
- What type of infection do you believe she has in this hand?
- From complaint and physical examination, which of the symptoms lead you to your choice of agent?
- From the history, which of the information confirmed your choice?
- Which of the following is most likely to follow this infection?
A "Strep" Infection in a Young Child Case Study
When 8-year-old Tyler from West Chester, Ohio, returned from a basketball tournamentin early March 2016, he had no idea what the next few days, weeks, andmonths had in store for him. When he awoke the next morning, he had a painin his hip and upper leg. Suspecting the pain was associated with an unseen bump from theprevious day, his father treated the symptoms. As the day progressed, the pain continued andTyler developed a fever. As a precaution, Tyler was taken to a local medical facility for evaluation.Other than pain and continuing fever, nothing unusual was found. A test for bacterialinfection was negative and he was sent home. His condition did not improve, and by midnighthe had become delirious. A call to the doctor, followed by a call to 911, resulted in Tyler being admitted to the Children'sHospital Medical Center in Cincinnati.
By the next morning, his condition had improved but the worst was not over. Whatfollowed was a seemingly unending array of pokes, prods, and procedures to test for "everydisease imaginable" including cancer. The most significant finding was a positive test for"Strep." A decision was made to transfer him to the ICU where he spent the next 6 weeks.
1. What is the organism commonly referred to as "Strep"?
2. What conditions are usually associated with this organism?
Animal Hides and Anthrax Disease Case Study
A 35-year-old male presentedto a London hospital complaining of difficulty breathing. His symptomsprogressed quickly, and he was transferred to the hospital's intensive treatment unit suffering from respiratoryfailure, which soon progressed to multiple organ failure. A blood culture revealed gram-positive, encapsulated,nonmotile rods preliminarily identified as Bacillus anthracis. This is the bacterium that causes the diseaseanthrax, and it has the ability to survive for long periods of time without water or nutrition. The presence ofB. anthraciswas later confirmed by the Novel and Dangerous Pathogens Division of Britain's Health Protection
Agency.
1. What characteristic of B. anthracisallows the bacterium to survive without water or nutrition?
2. Where is B. anthracisfound?
The 5 I's are Used in a Food Poisoning Outbreak Case Study
One August morning in 2015, a large proportion of the inmates at a Louisiana county jail awokecomplaining of nausea, vomiting, and diarrhea. The local health department suspected an outbreak of foodborneillness, and along with the Louisiana Department of Health and Human Services, initiated an investigation.
Because of the strict routine and controlled environment of prison life, it was relatively easy to findout what the inmates had eaten in the past 24 hours and how their food had been prepared. A writtenquestionnaire distributed to the inmates revealed 194 probable cases of food intoxication. Four respondentscommented on the unusual taste of the casserole they had eaten the night before, which contained macaroni,ground beef, ground turkey, frozen vegetables, and gravy. Stool samples were obtained from six symptomaticinmates and cultured for the presence of pathogenic bacteria.
1. What five basic techniques are used to identify a microorganism in the laboratory?
2. What types of media might a lab technician use to differentiate bacteria from one another?
Hepatitis C Infections at a Dialysis Clinic Case Study
Hepatitis C is achronic liver infection that can be either silent (with no noticeable symptoms) or
debilitating. Either way, 80% of infected individuals experience continuing liver destruction. Chronic hepatitis C infection is the leading cause of liver transplants in the United States. The virus that causes it is bloodborne, and therefore patients who undergo frequent procedures involving transfer of blood are particularly susceptible to infection. Kidney dialysis patients belong to this group. In 2008, a for-profit hemodialysis facility in New York was shut down after nine of its patients were confirmed as having become infected with hepatitis C while undergoing hemodialysis treatments there between 2001 and 2008.
When the investigation was conducted in 2008, investigators found that 20 of the facility's 162 patients had been documented with hepatitis C infection at the time they began their association with the clinic. All the current patients were then offered hepatitis C testing, to determine how many had acquired hepatitis C during the time they were receiving treatment at the clinic. They were considered positive if enzyme-linked immunosorbent assay (ELISA) tests showed the presence of antibodies to the hepatitis C virus.
1. Health officials did not test the workers at the hemodialysis facility for hepatitis C because they did not view them as likely sources of the nine new infections. Why not?
2. Why do you think patients were tested for antibody to the virus instead of for the presence of the virus itself?
Multiple Drug Resistance Case Study
Acinetobacterbaumanniiis a gram-negative bacterium commonly found in soil andwater. It has occasionally been linked with health-care-associated infections. Amonghospitalized patients, infections caused by A. baumanniihave become increasinglydifficult to treat due to an increasing number of isolates showing multiple drug resistance.Military medical facilities have seen an increasing number of patients with bloodstreaminfections caused by A. baumannii. Many of these patients had received traumatic injuries inIraq, Kuwait, or Afghanistan. Antimicrobial testing of isolates from patients being treated atLandstuhl Regional Medical Center in Germany and Walter Reed Army Medical Center in theDistrict of Columbia showed widespread resistance to antimicrobials commonly used to treatthis organism.
1. What could be the source of the infections seen in the military facilities?
2. What do we call infections that are acquired in a medical setting?
3. What is the significance in these isolates being resistant to multiple antibiotics?
MRSA Infection at the Zoo Case Study
Over the past severalyears, methicillin-resistant Staphylococcus aureus(MRSA) has become infamous asthe cause of skin infections among football players, wrestlers, fencers, and other athletes who share equipmentor engage in contact sports. MRSA strains are resistant to many drugs, including methicillin, a penicillinderivative commonly used to treat staphylococcal infections. Clinicians now distinguish between HA (hospital acquired)MRSA and CA (community-acquired) MRSA. Spread of the bacterium from the initial infection sitecan lead to serious (often fatal) involvement of the heart, lungs, and bones.
Humans are not the only victims of MRSA. On January 29, 2008, the San Diego Zoo reported a MRSAoutbreak involving a newborn African elephant and three of its human caretakers. The humans exhibitedcutaneous pustules that were laboratory confirmed as MRSA infection. An investigation was initiated todetermine the course and scope of the outbreak.
1. Was this an instance of HA-MRSA or CA-MRSA?
2. How is S. aureuscommonly spread?
Tracking a Measles Outbreak Case Study
The Ohio State Departmentof Health confirmed a diagnosis of measles in a 6-year-old girl who washospitalized in Cincinnati while visiting relatives in May 2005. Because the patient was a resident of Indiana, theIndiana State Department of Health initiated an investigation that eventually identified a total of 34 cases ofmeasles occurring between May 16 and June 24. Of the 34 infected persons, 33 had participated in a churchgathering in northwestern Indiana on May 15-or were family members of a participant. The final case occurredin a phlebotomist who worked at a hospital where one of the measles patients had been admitted; childhood school records indicated that he had received only one of two recommended doses of measles vaccine.
Three of the 34 patients were hospitalized, two with dehydration and one with pneumonia requiring6 days of mechanical respiratory support. Complications seen in the 31 nonhospitalized patients included16 cases of diarrhea and 2 cases of otitis media (ear infection). State and local health departments in Ohio,Indiana, and Illinois (where one patient lived) immediately began tracing the contacts of all 34 patients todetermine the outbreak's epidemiology.
1. What type of infectious agent is responsible for measles? How is measles spread?
2. Does this look like a point-source epidemic or a propagated epidemic? (See chapter 13 for a review of epidemiology.)
Warming Water and the Appearance of Gastrointestinal Illness Case Study
A Nevada resident whohad just returned home from a cruise on Prince William Sound in July 2007was struck by gastrointestinal distress so severe that medical intervention was required. Laboratory testsfor this patient indicated the presence of Vibrio parahaemolyticus, a pathogenic bacterium known to causegastroenteritis. Infection usually occurs through consuming raw or undercooked shellfish, particularly oysters.In this case, the patient's illness began 3 days after eating raw oysters from Prince William Sound.
Further investigation by the epidemiology section of the Alaska Division of Public Health revealed thata total of 54 people had developed watery diarrhea, along with various other gastrointestinal symptoms,beginning within 2 days of consuming raw oysters collected from Alaskan waters. Stool samples providedby eight patients all contained V. parahaemolyticus. However, the discovery of this bacterium was puzzlingbecause V. parahaemolyticusrequires a minimum water temperature of 16.5°C to survive, and the waters ofPrince William Sound have historically been colder than that.
1. Into which of three temperature classifications for bacteria does V. parahaemolyticusfall?
2. What could explain the change in the ability of V. parahaemolyticusto survive?
A Respiratory Infection Returns Case Study
Dana, a 21-year-old college student, was suffering from a persistent cough, fever, andconstant fatigue. She was asked whether she had these symptoms in the past and ifshe had been treated for them at that time. She reported that she had gotten sickwith similar symptoms before but never received any treatment. Since she had mild fever, andher chest X-rays were normal, her doctor prescribed streptomycin and cough medicine. Hersymptoms improved drastically within a week and, consequently, she decided to stop takingher medication.
After 2 months, she felt ill again. Her symptoms included coughing, loss of appetite, highfever, and night sweats. She said the cough, which had lasted for the past 3 weeks, was accompaniedby a blood-stained sputum.
A preliminary diagnosis was made based on the symptoms. Chest X rays, MantouxPPD test, and an acid-fast stain from a sputum sample were later performed. She also wastested for HIV. Based on the results of the tests and her symptoms, a cocktail of antibiotics,including isoniazid and rifampin, was prescribed. She was instructed to take the antibioticsfor 9 months.
1. What disease is described here?
2. Why might Dana's symptoms have resurfaced despite the original streptomycin treatment?
3. Why was it necessary to place Dana on a multidrug treatment?
Prairie Dog Die-Off Related to Teenager's Death Case Study
In August of 1996, a teenage girl living in Colorado was seen in the local hospital emergencydepartment. Her presenting symptoms were numbness in her left arm accompaniedby pain in the axilla region. Her temperature, pulse rate, blood pressure, and chest filmwere all within normal ranges. She reported recently having fallen from a trampoline. She wasreleased from the emergency department with a diagnosis of possible nerve injury to her leftarm and a prescription for painkillers.
Four days later, she was back in the emergency room in very bad shape. She was semiconscious,had a fever of 102.5°F, and pulse of 170 beats per minute. A new chest X-ray revealed bilateralpulmonary edema. She experienced respiratory failure while in the emergency room andwas intubated. Blood and cerebrospinal fluid (CSF) samples were taken for culture, cell count,glucose and protein analysis, and for Gram staining. Gram-positive diplococci were detectedin the blood. At this point, she was diagnosed with septicemia, disseminated intravascular coagulation,adult respiratory distress syndrome, and possible meningitis. A Gram stain of sputumrevealed no bacteria. Treatment for gram-positive sepsis was initiated.
The patient died later that day. Two days later, her blood and CSF cultures revealed anunidentified gram-negative rod and Streptococcus pneumoniae .As part of the epidemiological investigation after her death, health officials visited her home. The only possibly relevant informationthey found was a family cat with a healing abscess in its jaw and evidence of an extensiveprairie dog die-off in the vicinity.
1. What do you suppose was the cause of death in this case?
2. How is the pain in the left arm and underarm related to her infection?
Pertussis Case Study
In recent years vaccine-preventable diseases have caused a number of outbreaks in the United States. Such was the case in an Amish community in Kent County in southern Delaware.Between September 2004 and February 2005, a total of 345 cases of pertussis (also known as whooping cough) were identified in this close-knit community of 1,711 people. Nurses from the Delaware Department of Public Health detected the first cases among patients that were beingseen in the Southern Health Services clinic that serves the area. In order to control the spread ofthe disease, special pertussis clinics were set up in the Amish schools within the community. Theclinics provided a means to educate community members about prevention, control, and treatmentmeasures. In addition, local doctors and health care providers were notified and providedwith diagnostic kits. To determine the full extent of the outbreak, surveillance strategies weredeveloped. These included self-administered questionnaires and household interviews.
1. What causes pertussis and how is it diagnosed?
2. What measures can be taken to prevent outbreaks such as this one?
Foul Odor Accompanies Leg Wound Case Study
A 62-year old diabetic Black 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.
- What is your diagnosis in this case?
- How should this wound be treated?
- Is this a life-threatening condition?
- Is it likely that the patient's diabetes contributed to the problem as presented?
Fecal Accidents in Community Swimming Pool Case Study
During June of 2000, several children in Delaware, Ohio, were hospitalized at GradyMemorial General Hospital (GMH) after experiencing watery diarrhea, abdominalcramps, vomiting, and loss of appetite. Dr. McDermott, a new gastroenterologist atGMH, who also had a strong interest in infectious diseases, was asked to examine the children.Their illness lasted from 1 to 44 days, and nearly half of them complained of intermittent boutsof diarrhea. By July 20, over 150 individuals-mainly children and young adults between theages of 20 and 40-experienced similar signs or symptoms. Dr. McDermott suspected thattheir illness was due to a microbial infection and queried the Delaware City County HealthDepartment (DCCHD) to investigate this mysterious outbreak further.
Dr. McDermott helped the DCCHD team in surveying individuals hospitalized for intermittent diarrhea. They questioned individuals about recent travel, their sources of drinking water, visits topools and lakes, swimming behaviors, contact with sick persons or young animals, and day-careattendance. The DCCHD's investigation reported that the outbreaks were linked to a swimmingpool located at a private club in central Ohio. The swimming pool was closed on July 28. A totalof 700 clinical cases among residents of Delaware County and three neighboring counties wereidentified during the entire span of the outbreak that began late June and continued throughSeptember. At least five fecal accidents were observed during that time period at the pool. Onlyone of these accidents was of diarrheal origin. Outbreaks of gastrointestinal distress associatedwith recreational water activities have increased in recent years, with most being caused by theorganism in this case.
1. Do you know what microorganism might be the cause of the outbreak?
2. How can a single fecal accident contaminate an entire pool and cause so many clinical cases of gastrointestinal distress?
Diagnosing a Sore Throat Case Study
A lethargic 22-month old black female was presented by her mother to the emergency room at 2:15am on a Sunday. The child had a history of a runny nose, hoarse cough and low-grade fever (~99F) for the past 48 hours. The mother was concerned about the forced and noisy breathing of the child. The pediatrician examined the child and found cloudy eyes and mild inflammation of the ears, but no overt signs of bacterial infection (no significant changes in the eardrums). The throat of the child was red and coated with mucus. The larynx was swollen and raw.
The physician performed a rapid Strep test and found it was negative. Throat swabs were taken for culture. The physician placed the child in a room with a warm vaporizer for about 30 minutes. This dramatically improved the breathing of the child.
- What is the presumptive diagnosis for this case?
- Will the throat cultures likely show evidence of Streptococcus pyogenes? How about Staphylococcus aureus?
- Do you believe that this is a bacterial or viral disease? Why?
- What further treatment is indicated for this case?
Dangerous Waters Case Study
There are bacteria adaptedto survive in every kind of habitat. There are marine bacteria and freshwater bacteria -and even some that thrive only in brackish waters, which are part marine and part fresh.Lately, bacteria that live in brackish waters have been causing serious wound infections, and even somedeaths, in humans.
In 2006, a mortgage broker in his 30s fell into a harbor in Hawaii 6 days after a sewage pipe failure hadallowed 48 million gallons of sewage to flow into the harbor water. The man was admitted to the hospital, andwithin days he died from massive organ failure caused by septicemia with Vibrio vulnificus. You may be familiarwith Vibrio cholerae, the diarrhea agent. Its relative, V. vulnificus, tends to invade breaks in the skin and thenproliferate in the bloodstream, often causing massive infections necessitating amputation, and sometimes even leading to death.
1. Once the man was admitted to the hospital, what steps would you take to determine what was making him ill?
2. If you were a public official in charge of Hawaii's recreational waters, how would you determine when the waters were safe again?
Controlling Microbial Levels at a Water Park Case Study
The popular interactive waterfountain, or "sprayground," at Seneca Lake State Park closed for theremainder of the summer on August 17, 2005, after the New York State Health Commissioner announced thatan outbreak of cryptosporidiosis had been traced to the park. Cryptosporidiosis results from ingesting watercontaminated with the protozoan Cryptosporidium parvum. Symptoms include diarrhea, vomiting, fever, andabdominal cramps.
The sprayground itself is an 11,000-square-foot deck with hundreds of individual water jets, spouts, andhoses. After being sprayed into the air, water flows back into a holding tank below the play area before beingrecycled through the jets once again. This type of water playground has become immensely popular becauseeven small children can play there, without the risk of drowning commonly associated with swimming pools.
1. Would Cryptosporidium be more or less resistant to physical and chemical methods of control than most other microbes?
2. What level of microbial control would be most appropriate in this case: disinfection, sterilization, antisepsis, or decontamination?
Attempts to Control Salmonellosis Outbreak Case Study
An outbreak of salmonellosis occurred in a large university veterinary teaching hospital.
During the first 7 weeks of the outbreak, Salmonella infantiswas isolated from35 animals, including 28 horses, 4 cows, 1 camel, 1 goat, and 1 dog. Bacterial culturesof fecal samples collected at the time of admission were all negative for S. infantis. During thecourse of the outbreak, several infected horses developed fever and diarrhea, and some veterinarystudents felt that they might have been infected.
A total of 148 environmental samples were collected for bacterial culture during weeks 1 through 7 of the outbreak, and isolates of S. infantiswere obtained from rectal thermometers,the rubber mat flooring of a horse stall, and from the hands of one hospital worker.
The large-animal portion of the veterinary teaching hospital was closed. The facility wasthen cleaned by high-pressure power washing and disinfected with a quaternary ammoniumproduct. Surgical recovery stall mats were cleaned a second time with a hydrogen peroxideproduct. Individual stall-side thermometers were stored in 0.5% chlorhexidine solution.Salmonella was not isolated upon resampling of the cleaned facility, and the hospital wasreopened.
The first two animals admitted after reopening, a horse and a cow, were found to be positivefor S. infantisin their feces after only a few days. Environmental samples were again positive.
A second outbreak ensued. The second outbreak was worse-over 80% of the animals with Salmonella in their feces also had fever or diarrhea. Two foals failed to respond to treatment andwere humanely euthanized.
1. Why do you think the sanitizing and disinfection failed to control the Salmonella?
Botulism from Chili Sauce Case Study
An Indiana husband and wife,both feeling ill, went to separate hospitals to be examined, and severalpotential diagnoses were suggested. A few days later, on July 11, 2008, both patients were evaluated at thesame hospital. There, physicians were able to make a preliminary diagnosis of botulism based on the couple'sshared symptoms, which included cranial nerve palsy and descending flaccid paralysis. Both patients requiredmechanical ventilation. During a search of the couple's refrigerator, local health officials found an unlabeledbag of leftover chili sauce that, when analyzed, contained botulin, the bacterial toxin that causes botulism.Botulin is produced by Clostridium botulinum, an endospore-forming bacterium. Because botulism is a reportable disease, the facts of the case were forwarded to the Indiana State Department of Health and theCenters for Disease Control and Prevention (CDC).
Four days earlier, the CDC had received a similar report from Texas, where two siblings had beendiagnosed with botulism, again only after being examined at the same hospital. Both children had eatenCastleberry's Hot Dog Chili Sauce for lunch on June 28. Although the can from this meal had been discarded,another can, bought at the same time, was found in the home.
Based on these two cases, the CDC suspected a common source epidemic.
1. What conditions encourage the germination of Clostridium botulinum endospores?
2. What is a common source epidemic?
Back Pain Appears Following Nail Puncture Case Study
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.
- What is your diagnosis here?
- What is the proper treatment of this problem?
- How could this have been prevented?