Author: Dr Katherine Allnutt, Resident, Monash Health, Melbourne, Australia. DermNet NZ Editor-in-Chief: A/Prof Amanda Oakley, Dermatologist, Hamilton, New Zealand. February 2018. 

What is listeriosis?

Listeriosis is a bacterial infection caused by the bacteria Listeria monocytogenes. It is typically a food-borne illness and usually affects those with impaired immunity. Its presentation may range from febrile gastroenteritis to potentially fatal invasive disease, including sepsis, central nervous system infection and perinatal infection [1].

Listeriosis may also uncommonly present with cutaneous eruptions.

Who gets listeriosis?

Most cases of reported listeriosis are sporadic but a number of outbreaks have occurred [1].

Clinical listeriosis mostly occurs in high-risk groups including [2]:

What causes listeriosis?

Listeria monocytogenes is an anaerobic gram-positive bacillus found in vegetation, soil and animals. Consumption of contaminated food is thought to be the main route of transmission. The bacterium can survive acidic, salty and cold food processing techniques and can continue multiplying even with proper refrigeration [1]. The incubation period is variable and outbreaks have occurred 3–70 days following exposure to implicated food products [4]. The median incubation period is approximately 3 weeks.

 The following are considered high-risk products [4]:

  • Unpasteurised dairy products
  • Soft cheese
  • Pâté
  • Raw or smoked seafood
  • Pre-packed cold salads
  • Delicatessen foods that have not been reheated adequately
  • Sprouted seeds and raw mushrooms.

Listeria monocytogenes may also be transmitted from mother to baby, via the placenta or from ascending vaginal infection [1].

Rarely, Listeria monocytogenes may be transmitted from animals to humans [1].

Most cases of cutaneous listeriosis in adults result from direct inoculation of the skin [3]. This is most commonly seen in veterinarians or farmers who come in contact with animal products of conception or soil carrying the bacteria. Cutaneous listeriosis may also appear from invasive disease through haematogenous spread in individuals with impaired immunity [3].

Foods that may carry listeria

What are the clinical features of listeriosis?

In immune-competent individuals, non-invasive listeriosis typically manifests as febrile gastroenteritis with self-limiting nausea, vomiting and diarrhoea [2].

  • In elderly patients and those with impaired immunity, invasive listeriosis most frequently presents as sepsis or central nervous system infection with fever and neurological signs.
  • Listerial bacteraemia or septic emboli from listerial endocarditis can lead to localised infections including hepatitis, cholecystitis, peritonitis, splenic abscess, pericarditis, pleuritis, endophthalmitis and osteomyelitis.
  • Cellulitis, lymphadenitis and conjunctivitis from direct inoculation have been described [2].

Maternal T-cell immunity is most affected during the third trimester and this is when listeriosis in pregnancy typically occurs [1].

  • Mothers tend to develop flu-like symptoms but may be asymptomatic [5].
  • Perinatal infection can result in miscarriage, stillbirth, preterm delivery, neonatal sepsis or meningitis.
  • Neonatal listeriosis may be classified as early-onset, which occurs within the first week of life and is most often associated with sepsis, or late-onset, which is commonly associated with meningitis [5].
  • Granulomatosis infantisepticum is a severe form of generalised neonatal infection, which can cause granulomatous lesions involving multiple organs including the skin [5].

Clinical features of cutaneous listeriosis

Cutaneous listeriosis typically presents as purpuric, papulopustular or vesicopustular eruptions that are painless and non-pruritic [3].

  • Cellulitis with abscess formation has less commonly been described [6].
  • Eruptions generally occur on exposed areas such as hands and forearms [3].
  • The median time from exposure to onset of rash is 2 days.
  • Many patients experience systemic symptoms, of which fever is the most common.
  • Associated regional adenopathy and lymphangitis have been reported [7].
  • In neonates, the rash is typically more widespread. Granulomatosis infantisepticum presents with an erythematous rash with widespread small, pale papules [8].

How is listeriosis diagnosed?

Listeriosis is diagnosed by isolating Listeria monocytogenes from a site that is normally sterile, such as blood, cerebrospinal fluid, gastric washings, amniotic fluid, meconium, placenta or fetal tissue specimens [1]. The bacterium may also be isolated from a skin biopsy.

  • Listeria may be present asymptomatically as normal vaginal and gut flora therefore samples of these are not useful in diagnosis [9].
  • Microscopy and culture or polymerase chain reaction (PCR) may be used for detection.
  • Molecular subtyping may help determine the association between isolates from cases and any products that test positive for Listeria monocytogenes [4].
  • Serology testing for listeriosis is not very specific or sensitive [1].

Histopathology may demonstrate:

  • Mild spongiosis and lymphocytic exocytosis or pustules with subcorneal intraepidermal collections of neutrophils [10].
  • Mixed acute and chronic inflammatory infiltrate in the dermis including prominent macrophages with intracellular and free coccobacillus on Gram stain or heamatoxylin and eosin (H&E) stain.
  • Ggranulomas in granulomatosis infantisepticum [8].

An elevated white cell count on full blood examination is usually found.

Imaging may demonstrate abscesses on internal organs such as the liver and brain.

What is the differential diagnosis for cutaneous listeriosis? 

Listeriosis presents like many other infectious diseases that cause fever and constitutional symptoms. The differential diagnosis for cutaneous listeriosis is wide and may include:

  • Folliculitis
  • Contact dermatitis
  • Localised herpetic infection.

Differentials to consider based on histopathology include infections with intracellular microorganisms such as granuloma inguinale, rhinoscleroma and leishmaniasis [10].

What is the treatment for listeriosis?

Listeriosis is treated with antibiotics.

Penicillin alone, or with gentamicin, is considered the drug of choice for treatment of listeriosis. Vancomycin, meropenem and linezolid have also been used successfully in case reports [1,11,12,13]. In patients who are allergic to pencillin, trimethoprim-sulphamethoxazole or erythromycin may be used [1]. Listeria monocytogenes is resistant to cephalosporins.

The duration of treatment varies depending on age, location and severity of illness.

There is limited evidence on the role of antibiotics in primary cutaneous listeriosis but it has been proposed that a 5–7 day course of oral amoxicillin or trimethoprim-sulphamethoxazole may be warranted [3]. 

Listeriosis should be notified to the relevant local authorities [4]. If contaminated products are implicated these may need to be recalled. 

How can listeriosis be prevented?

Immunisation for listeriosis is not currently available.

  • The risk of exposure may be minimised through hygienic food preparation and storage.
  • It is recommended that pregnant women and immunocompromised individuals avoid high-risk food products.
  • Wearing protective equipment such as gloves when working with livestock or gardening may assist in preventing cutaneous listeriosis.  

What is the outcome for listeriosis?

Listeriosis is usually a self-limiting disease in immunocompetent individuals, however, mortality rates in invasive disease may be as high as 20% [14]. One third of cases of listeriosis in pregnancy result in miscarriage or stillbirth [1].

Primary cutaneous listeriosis usually resolves without long-term consequence [3].  

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Related information



  1. Allerberger F, Wagner M. Listeriosis: a resurgent foodborne infection. Clin Microbiol Infect 2010; 16:1 6-23. DOI: 10.1111/j.1469-0691.2009.03109.x. PubMed.
  2. Doganay M. Listeriosis: clinical presentation. FEMS Immunol Med Microbiol2003; 35: 173–75. PubMed.
  3. Goodshall C, Suh G, Lorber B. Cutaneous listeriosis. J Clin Microbiol 2013; 51(11): 3591-3596. DOI: 10.1128/JCM.01974-13. PubMed.
  4. New Zealand Ministry of Health. Listeriosis. Communicable Disease Control Manual. 2012. Available at: (accessed 17 December 2017).
  5. Posfay-Barbe KM, Wald ER. Listeriosis. Sem Fetal Neonat Med 2009; 14(4): 228-233. DOI: 10.1016/j.siny.2009.01.006. PubMed.
  6. Vásquez A, Ramos JM, Pacho E, Rodríguez-Pérez A, Cuenca-Estrella M, Esteban J. Cutaneous listeriosis in a patient infected with the immunodeficiency virus. Clin Infect Dis 1994; 19(5): 988–989. PubMed.
  7. Laureyns J, Moyaert H, Werbrouck H, Catry B, de Kruif A, Pasmans F. Pustular dermatitis by Listeria monocytogenes after the assisted delivery of a dead calf. Vlaams Diergeneeskundig Tijdschrift 2008; 77: 29–34.
  8. Baker CJ. Listeriosis. In: Red Book Atlas of Pediatric Infectious Diseases, 3rd edn. American, Academy of Pediatrics, 2017: 339-343.
  9. Jankiraman V. Listeriosis in pregnancy: diagnosis, treatment and prevention. Rev Obstet Gynecol 2008; 1(4): 179–185. PubMed.
  10. Cockerell C, Mihm MC, Hall B, Chisholm C, Jessup C, Merola MC. Bacterial Infections. In: Dermatopathology: Clinicopathology Correlations. Springer Science and Business Media, 11 Dec 2013: 201-214.
  11. Lorber B. Listeria monocytogenes. In: Principles and Practice of Infectious Diseases, 7th edn, Mandell GL, Bennett JE, Dolin R (Eds), Churchill Livingstone, Philadelphia 2010: 2707.
  12. Morosi S, Francisci D, Baldelli F. A case of rhombencephalitis caused by Listeria monocytogenes successfully treated with linezolid. J Infect 2006; 52: e73-75. DOI: 10.1016/j.jinf.2005.06.012. PubMed.
  13. Manfredi R, Sabbatani S, Marinacci G, Salizzoni E, Chiodo F. Listeria monocytogenes meningitis and multiple brain abscesses in an immunocompetent host. Favorable response to combination linezolid-meropenem treatment. J Chemother 2006; 18: 331-333. DOI: 10.1179/joc.2006.18.3.331. PubMed.
  14. Guevara R, Mascola L, Sorvillo F. Risk factors for mortality among patients with non- perinatal listeriosis in Los Angeles County, 1992-2004. Clin Infect Dis2009; 48(11): 1507-15. DOI: 10.1086/598935. PubMed

On DermNet NZ

Other websites

  • Listeriose — translation of this page in Portuguese by Artur Weber and Adelina Domingos
  • Centers for Disease Control and Prevention. Listeriosis. Available at: Updated 16 March 16 2015 (accessed 17 December 2017).
  • Listeria — Ministry of Health, New Zealand.
  • Listeria —, US Department of Health & Human Services

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