<unk>  is a heterogeneous group of infectious diseases caused by Listeria spp. (commonly Listeria monocytogenes), a flagellated, catalase-positive, facultatively intracellular, anaerobic, gram-positive bacillus.<unk>  is a relatively uncommon infection with an annual incidence of<unk>  in the United States ranging between 0.2 to 0.3 cases per 100,000 individuals. Listeria is commonly transmitted via contaminated food or via vertical transmission from mother to fetus. Following transmission, Listeria encodes thermoregulated virulence factor in the human host, invades the intestinal epithelium, and multiplies intracellularly within phagocytic phagolysosomes. Following transmission, Listeria may cause any the following syndromes: neonatal<unk> , genitourinary infection, gastroenteritis, central nervous system infection, endocarditis, bacteremia, and localized infection. Risk factors in the development of<unk>  include ingestion of uncooked meats and vegetables, unpasteurized (raw) milk and cheeses, processed (or ready-to-eat) meats and smoked seafood.  Populations at higher risk of developing<unk>  include immunosuppressed patients (e.g. transplant recipients, patients with history of splenectomy, patients receiving immunosuppressive therapy, or patients with advanced diabetes, kidney/ liver disease, or active malignancy),  neonates, pregnant women, and elderly patients. The majority of healthy patients do not develop clinical manifestations or may develop a mild, transient bacteremia. Early clinical manifestations (usually fever) typically develop early within 24 hours of transmission. If left untreated, patients typically progress within 1-90 days to develop Listeria-associated complications, including bacteremia, abscess formation, pneumonia, ARDS, acute kidney injury, and CNS impairment. Among healthy children and young adults, the prognosis of<unk>  is generally good. Prognosis is poorer among high-risk populations, who are more likely to develop complications and death even with prompt management. For symptomatic patients, diagnosis of<unk>  is confirmed following the isolation of Listeria monocytogenes from a normally sterile site, such as blood, spinal fluid (in the setting of nervous system involvement), or amniotic fluid/placenta (in the setting of pregnancy). Nonetheless, the diagnosis of<unk>  requires a high pre-test probability, given the organism's morphological similarity to other organisms, variability in clinical manifestations, and low rates of Gram-staining. All patients with<unk>  require antibiotic therapy. Ampicillin, with or without gentamicin, is the antibiotic of choice for the treatment of<unk> . Patients intolerant to penicillins may be managed with trimethoprim-sulfamethoxazole. Duration of therapy depends on the clinical syndrome and may range from several days in non-complicated gastroenteritis to 6 weeks in endocarditis or encephalitis. Listerial gastroenteritis is frequently self-limited among healthy adults, but a short course of oral ampicillin may be considered among immunocompromised or pregnant individuals or those who have ingested food implicated in outbreaks. Non-gastroenteritis<unk>  often requires hospitalization and intravenous (IV) antibiotic therapy. Surgery may be required among patients who develop complications, such as abscess formation or advanced endocarditis. General recommendations for the primary prevention of infection with Listeria include appropriately washing and handling of food, maintaining a clean and safe kitchen and environment, cooking meat and poultry thoroughly, safely storing foods, and choosing safe foods. There are no vaccines against<unk> , and pharmacologic prophylaxis is not recommended.
Listeriosis
Scarlet fever
Scrub typhus
Boutonneuse fever
Bartonellosis
Salmonellosis
Leptospirosis
Legionellosis