A 65-year-old woman with ovarian cancer undergoing chemotherapy is hospitalized due to fever, headache, ataxia, and progressive confusion. Two days later, a 26-year-old pregnant woman is admitted to the same hospital with fever, nausea, vomiting, diarrhea, and muscle aches and spontaneously delivers a preterm infant who has generalized skin rash. Laboratory evaluation reveals that these patients' conditions were caused by the same microbial organism. The state health department is notified. Reports of similar illnesses are noted in neighboring cities. A subsequent investigation reveals that 8 people were affected, all of whom consumed food products from a single processing facility. Which of the following organisms is most likely responsible for this outbreak?

Question

A 65-year-old woman with ovarian cancer undergoing chemotherapy is hospitalized due to fever, headache, ataxia, and progressive confusion.  Two days later, a 26-year-old pregnant woman is admitted to the same hospital with fever, nausea, vomiting, diarrhea, and muscle aches and spontaneously delivers a preterm infant who has generalized skin rash.  Laboratory evaluation reveals that these patients' conditions were caused by the same microbial organism.  The state health department is notified.  Reports of similar illnesses are noted in neighboring cities.  A subsequent investigation reveals that 8 people were affected, all of whom consumed food products from a single processing facility.  Which of the following organisms is most likely responsible for this outbreak?

Quizplus · Accepted Answer

Listeria monocytogenes is a facultative intracellular gram-positive bacillus that can multiply at refrigerated temperatures in both anaerobic and microaerophilic conditions. It is an important cause of foodborne illness; outbreaks are frequently associated with consumption of contaminated food products (eg, processed meats, soft cheeses, raw fruits & vegetables). Healthy patients who ingest high inoculums of Listeria are at risk for febrile gastroenteritis. Invasive infections such as sepsis and meningoencephalitis are primarily seen in patients with impaired cell-mediated immunity (eg, AIDS, malignancy, extremes of age, pregnancy). Pregnant women are at greatest risk in the third trimester and often present with flu-like symptoms and diarrhea. Infection during pregnancy can cause preterm labor, neonatal sepsis, or granulomatosis infantiseptica (ie, infant with papular & pustular skin lesions, widespread abscesses/granulomas). (Choice A) Epidemic fungal meningitis due to Aspergillus fumigatus has been associated with contaminated glucocorticoid injections. Aspergillus is not typically associated with foodborne illness. (Choices B and D) Cytomegalovirus and herpes simplex virus can cause a variety of clinical syndromes in immunocompromised patients, including encephalitis, esophagitis, pneumonitis, and colitis. These viruses are ubiquitous and not associated with foodborne outbreaks. (Choice C) Foodborne outbreaks of Escherichia coli O157:H7 have been linked to the ingestion of contaminated beef (primarily) and are usually associated with hemorrhagic colitis. Patients may also develop hemolytic uremic syndrome. Meningitis and neonatal infection would be atypical. (Choice F) Neisseria meningitidis causes sepsis and acute meningitis. It is transmitted primarily by respiratory droplets; most cases occur in those who live in congregate settings (eg, dormitories, military barracks). (Choice G) Streptococcus pneumoniae is a common cause of bacterial meningitis in elderly and immunocompromised individuals but is not associated with foodborne outbreaks. (Choice H) Toxoplasma may be acquired via consumption of undercooked meat and unwashed produce or contact with cat feces. It is associated with meningoencephalitis in immunocompromised patients (eg, advanced AIDS). In immunocompetent individuals, toxoplasmosis is usually asymptomatic but may present with flu-like symptoms and lymphadenopathy; diarrhea would be less likely. Educational objective: Listeria is a relatively common foodborne illness associated with outbreaks after the consumption of contaminated food, particularly processed meats and dairy products. Healthy patients may develop gastroenteritis; patients with impaired cell-mediated immunity are at risk for invasive infection (eg, sepsis, meningoencephalitis); and listeriosis in pregnancy is associated with adverse fetal outcomes (eg, fetal death, premature birth).

A 65-Year-Old Woman with Ovarian Cancer Undergoing Chemotherapy Is Hospitalized