L. monocytogenes is a bacterial agent that leads to two separate clinical manifestations, depending on the age and immunological status of the infected individual.

To begin with, listeriosis presents with a clinical picture of food poisoning accompanied by fever in otherwise healthy individuals. Symptoms derived from the invasion of the gastrointestinal tract predominate and the disease recedes after some time, similar to food poisoning from other pathogens. Contrary to this, people of younger or older ages (senior population and newborns), people who are immunocompromised and women who are pregnant exhibit symptoms of a more profound illness that includes meningoencephalitis and septicemia, when infected with the microorganism.

Specifically with regard to neonates, listeriosis can either be diagnosed within less than 5 days after birth (early onset) or within a period of time that exceeds the 5-days limit (late onset). The manifestations differ according to the type of neonate listeriosis: early onset infection leads to meningitis and septicemia, while late onset disease is more commonly associated with purulent meningitis. Neonates usually present with an irregular temperature fluctuation, respiratory imbalance, lethargy and poor appetite, while appearing irritable, tachypnoic and prone to epileptic phenomena. The typical histopathological characteristic of listeriosis is the presence of a rash that is identified as containing granulomatous nodules.

• Fever

  Listeriosis is a rare cause of fever of unknown origin in patients with oral cancer. We report two patients who, because of pain and discomfort, ate large quantities of soft cheeses; this caused listeriosis and fever. [ncbi.nlm.nih.gov]

  Symptoms of meningitis include fever, headache, stiff neck, loss of balance, decreased level of consciousness and seizures. Symptoms of a blood infection include fever, nausea, vomiting and severe muscle aches. [healthlinkbc.ca]

  chills, severe headache, vomiting, and other influenza-type symptoms. [18, 28] Along these same lines, the CDC notes that infected individuals may develop fever, muscle aches, and sometimes gastrointestinal symptoms such as nausea or diarrhea. [11] [about-listeria.com]

• Chills

  Two of a patient's blood cultures grew L monocytogenes after she experienced chills, headache, myalgia, and diarrhea. [ncbi.nlm.nih.gov]

  Symptoms vary but may include: fever and chills headache stiff neck and sensitivity to light confusion and drowsiness muscle aches and pains nausea (feeling sick) diarrhoea. [healthywa.wa.gov.au]

  You can get it from lots of types of food, but it's mainly a problem with chilled, ready-to-eat foods, such as: cooked sliced meats and cured meats smoked fish and cooked shellfish blue veined and mould-ripened soft cheeses, like camembert and brie pâté [nhs.uk]

  Symptoms can include fever, fatigue, chills, headache, backache, general aches, upset stomach, abdominal pain and diarrhea. [fsis.usda.gov]

• Fatigue

  Pregnant women : Pregnant women typically experience only fever and other flu-like symptoms, such as fatigue and muscle aches. [cdc.gov]

  […] self-limited gastro enteritis, watery diarrhea Pregnant women: flu-like illness, chorioamnion itis, spontaneous abortion, sepsis Infants : neon atal meningitis or sepsis, granulomatosis infantiseptica Immunocompromised : Fever, headache, muscle aches, fatigue [amboss.com]

  Symptoms can include fever, fatigue, chills, headache, backache, general aches, upset stomach, abdominal pain and diarrhea. [fsis.usda.gov]

• Malaise

  Soft cheeses and unpasteurized milk have been the most frequently incriminated dairy products. [4, 5, 6, 7, 8, 9, 10] Ingestion of Listeria by pregnant women can result in nausea, vomiting, diarrhea, fever, malaise, back pain, and headache. [11] Many [emedicine.medscape.com]

  General malaise and fever may be present after a few days. This generalized disease may be fatal. Colonization of various parts of the body, such as joints or endocardium, may lead to chronic disease accompanied by local symptoms. [ncbi.nlm.nih.gov]

• Veterinarian

  Most cases follow direct inoculation of the skin in veterinarians or farmers who have exposure to animal products of conception. Less commonly, skin lesions may arise from hematogenous dissemination in compromised hosts with invasive disease. [ncbi.nlm.nih.gov]

  This infection occurs after direct exposure to L. monocytogenes by intact skin and is largely confined to veterinarians who are handling diseased animals, most often after a listerial abortion.It can be more common in patients with hemochromatosis. [en.wikipedia.org]

• Sore Throat

  Symptoms of listeriosis range from showing no symptoms to having diarrhea, fever, muscle pain, joint pain, headache, stiff neck, backache, chills, sensitivity to bright light, and/or sore throat with fever and swollen glands. [mothertobaby.org]

  Fever, backache, headache, vomiting/diarrhea, myalgias and sore throat may occur. Importantly, up to 30% of gravidas with listeriosis will be asymptomatic. [clinicaladvisor.com]

  You might also have muscle aches or a sore throat.” Some people also have diarrhea. Because the symptoms are so nonspecific, it’s impossible to tell if you have listeriosis solely based on symptoms. [thebump.com]

• Diarrhea

  The patient had cirrhosis, a portosystemic shunt, and diarrhea for which she was being evaluated. Only one previous report has linked colonoscopy to listeriosis. [ncbi.nlm.nih.gov]

  [11] When present, the diarrhea usually lasts 1-4 days (with 42 hours being average), with 12 bowel movements per day at its worst. [18] Most healthy adults and children who consume contaminated food experience only mild to moderate symptoms. [about-listeria.com]

  Healthy adults: self-limited gastro enteritis, watery diarrhea Pregnant women: flu-like illness, chorioamnion itis, spontaneous abortion, sepsis Infants : neon atal meningitis or sepsis, granulomatosis infantiseptica Immunocompromised : Fever, headache [amboss.com]

• Nausea

  Ten (28%) of 36 party attenders met a case definition, which included isolation of Listeria monocytogenes from blood or stool or two of the following: fever, musculoskeletal symptoms, nausea, vomiting, diarrhea. [ncbi.nlm.nih.gov]

  The infection starts with flu-like symptoms such as fever, chills, muscle aches, nausea, and sometimes diarrhoea. "In immunosuppressed patients, listeriosis usually presents as a brain inflammation, brain abscess or blood poisoning. [abc.net.au]

  Symptoms of a blood infection include fever, nausea, vomiting and severe muscle aches. Listeriosis can also cause miscarriage or stillbirths in pregnant women. [healthlinkbc.ca]

  Clinical features A person with listeriosis usually presents with fever, headache, and sometimes gastrointestinal symptoms such as nausea, vomiting and diarrhoea. [chp.gov.hk]

• Abdominal Pain

  — Amy Barrett also : a disease or sickness caused by infection with this bacterium : listeriosis Listeria symptoms include high fever, severe headache, stiffness, nausea, abdominal pain and diarrhea. — Sierra Brown [merriam-webster.com]

  Symptoms can include fever, fatigue, chills, headache, backache, general aches, upset stomach, abdominal pain and diarrhea. [fsis.usda.gov]

• Tachycardia

  Under antibiotics (ampicillin and ciprofloxacin), the course was marked by respiratory failure requiring mechanical ventilation, coma, hypotension, tachycardia. and death 12 days after admission. [ncbi.nlm.nih.gov]

  Clinicians should be particularly suspicious for listeria infection if the patient develops evidence of chorioamnionitis (fever, uterine tenderness, fetal tachycardia) in the absence of rupture of the fetal membranes. [clinicaladvisor.com]

• Back Pain

  Others have a fever and other flu-like symptoms, such as chills, aches, and headache; back pain; or possibly gastrointestinal symptoms. Less commonly, the infection attacks your central nervous system. [babycenter.com]

  Soft cheeses and unpasteurized milk have been the most frequently incriminated dairy products. [4, 5, 6, 7, 8, 9, 10] Ingestion of Listeria by pregnant women can result in nausea, vomiting, diarrhea, fever, malaise, back pain, and headache. [11] Many [emedicine.medscape.com]

• Myalgia

  Two of a patient's blood cultures grew L monocytogenes after she experienced chills, headache, myalgia, and diarrhea. [ncbi.nlm.nih.gov]

  Fever, backache, headache, vomiting/diarrhea, myalgias and sore throat may occur. Importantly, up to 30% of gravidas with listeriosis will be asymptomatic. [clinicaladvisor.com]

  Symptoms include fever, myalgias, arthralgias and headache. Miscarriage, stillbirth and preterm labor are complications of this infection. Symptoms last 7–10 days. Neonatal infection (granulomatosis infantiseptica): There are two forms. [en.wikipedia.org]

• Headache

  Two of a patient's blood cultures grew L monocytogenes after she experienced chills, headache, myalgia, and diarrhea. [ncbi.nlm.nih.gov]

  Listeriosis can start with symptoms, such as: fever; nausea vomiting diarrhea; muscle aches; and headache Listeriosis can cause serious illness such as meningitis, blood infection and even death. [healthlinkbc.ca]

  […] infection Oculoglandular listeriosis Sepsis due to Listeria monocytogenes Clinical Information Gram positive bacterial infection with the genus listeria including listeria meningitis which causes clinical manifestations including fever, altered mentation, headache [icd9data.com]

  […] infection, the resulting illness is either mild or quite severe, in what is sometimes referred to as a “bimodal distribution of severity.” [13, 28] On the mild end of the spectrum, listeriosis usually consists of the sudden onset of fever, chills, severe headache [about-listeria.com]

• Confusion

  We describe a case of presumed listeria monocytogenes rhomboencephalitis, which was initially confused with leptomeningeal carcinomatosis in a patient with a malignant carcinoid tumor. [ncbi.nlm.nih.gov]

  If infection spreads to the nervous system, symptoms such as headache, stiff neck, confusion, loss of balance, or convulsions can occur. [epi.publichealth.nc.gov]

• Ataxia

  We present the case of a 62-year-old male with an unremarkable medical history admitted to the Iasi Infectious Diseases Hospital for fever. headache, ataxia, and diplopia. [ncbi.nlm.nih.gov]

  […] meningitis or sepsis, granulomatosis infantiseptica Immunocompromised : Fever, headache, muscle aches, fatigue Nausea, vomiting, watery diarrhea Sepsis Listeria meningitis Neck stiffness Mental status change, impaired consciousness (even coma ) Tremor, ataxia [amboss.com]

• Neck Stiffness

  […] illness, chorioamnion itis, spontaneous abortion, sepsis Infants : neon atal meningitis or sepsis, granulomatosis infantiseptica Immunocompromised : Fever, headache, muscle aches, fatigue Nausea, vomiting, watery diarrhea Sepsis Listeria meningitis Neck [amboss.com]

  Symptoms of listeriosis are often flu-like and can include nausea, vomiting, cramps, diarrhea, high fever, severe headache and neck stiffness. [web.archive.org]

In order to diagnose a Listeria infection, the culprit has to be isolated from samples that should, under normal conditions, be completely sterile. For this reason, blood and cerebrospinal fluid cultures are the first samples provided from testing. Depending on the affected regions, other fluids can prove helpful: joint fluid, pericardial and pleural fluid, alongside the amniotic fluid and placenta can be used in order to identify a suspected Listeria infection. In case the brain or hepatic regions appear affected, a magnetic resonance imaging scan or a computerized tomography scan can be performed, in order to detect possible abscesses.

Given that listeriosis can prove fatal to the population groups that are most sensitive to the infection, every pregnant woman who presents with fever and symptomatology compatible with food poisoning should undergo a blood culture in order to exclude this specific infection.

• Neutrophilia

  Laboratory test showed leukocyt osis with neutrophilia. pathological CSF findings (high WBC count with predominance of neutrophils, low glucose and high protein levels), increased liver enzymes (ALAT, ASAT, AP, gammaGT), and important renal impairment [ncbi.nlm.nih.gov]

• Listeria Monocytogenes

  Listeria monocytogenes infections in patients with AIDS: report of five cases and review. Rev Infect Dis. 1991 May-Jun. 13(3):413-7. [Medline]. Farber JM, Peterkin PI. Listeria monocytogenes, a food-borne pathogen. [emedicine.com]

  Seza Arslan and Selin Baytur, Prevalence and antimicrobial resistance of Listeria species and subtyping and virulence factors of Listeria monocytogenes from retail meat, Journal of Food Safety, 10.1111/jfs.12578, (e12578), (2018). [doi.org]

  Listeria monocytogenes was isolated from cerebrospinal fluid (CSF) and blood of the baby, and also from the genital tract of the mother. Unfortunately, the baby died before the preliminary report could be communicated. [ncbi.nlm.nih.gov]

• Gram-Positive Rods

  […] lis·te·ria | \ li-ˈstir-ē-ə \ : any of a genus ( Listeria ) of small, gram-positive, rod-shaped bacteria that do not form spores and have a tendency to grow in chains and that include one ( Listeria monocytogenes ) that causes listeriosis A common germ [merriam-webster.com]

  Structure and Classification Erysipelothrix rhusiopathiae is a slender, Gram-positive rod similar to L monocytogenes. In general, E rhusiopathiae rods are longer, especially in rough variants. [ncbi.nlm.nih.gov]

  L monocytogenes is a facultative anaerobe Gram-positive rod. More than likely, gravidas presenting with the flu-like symptoms noted above indeed have a viral syndrome. [clinicaladvisor.com]

  Background Information L. monocytogenes is a motile gram-positive rod. It produces disease and asymptomatic carriers in both humans and animals. [viceprovost.tufts.edu]

  Student Presentation on Listeria monocytogenes by Jamie Puglisi Introduction Listeria monocytogenes, a motile, gram-positive rod, is an opportunistic food-borne pathogen capable of causing listeriosis in humans. [web.uconn.edu]

• Blood Culture Positive

  Blood-culture positive patients and those receiving adjunctive dexamethasone had higher neurolisteriosis mortality. [32] Age Listeria infections occur most often in newborns and elderly patients. [emedicine.medscape.com]

  In this outbreak, another attendee hospitalized two days after the meal for fever and diarrhea, had blood cultures positive for Lm. He was subsequently treated and did not develop CNS symptoms. [bmcinfectdis.biomedcentral.com]

• Gram-Positive Bacteria

  Listeria are gram-positive bacteria which can infect humans as well as animals. [flexikon.doccheck.com]

  Listeriosis requires rapid treatment with antibiotics and most drugs suitable for Gram-positive bacteria are effective against L. monocytogenes. [ncbi.nlm.nih.gov]

Newborns are amongst the individuals who are expected to develop severe complications from listeriosis, if the infection remains undiagnosed or treated inappropriately. For these reasons, a neonate diagnosed with listeriosis should receive adequate antimicrobial coverage and supportive cardiovascular, pulmonary and nutritional care and monitoring. Extremely complicated cases of listeriosis in newborns should be mandatorily treated in an intensive care unit.

Antibiotics

The most effective antimicrobial agents against listeria are those that are able to penetrate the host's cellular barrier and achieve concentrations high enough in order to combat the pathogen. Adherence to the microorganism's PBP3 (penicillin-binding protein 3) is necessary, so as to eradicate the bacterium. Especially for cases diagnosed during pregnancy, the antibiotic has to possess the ability to surpass the placental barrier as well.

Ampicillin is the drug of choice and it is administered simultaneously with an antibiotic of the aminoglycoside group, most commonly gentamicin. The dosage depends on the age, gestational or not, and the severity of the clinical picture. Penicillin G can also be administered as an alternative to ampicillin and Sulfamethoxazole/Trimethoprim as a second alternative therapeutic approach in cases of penicillin hypersensitivity.

Prognosis relies upon the presence of complications such as meningitis, hydrocephalus or shock. Although there are protocols for the treatment of Listeria-induced meningitis [7], other manifestations, such as rhombencephalitis or the spread of the infection to the cranial nerves [8] [9] are still markedly grim prognostic factors.

Listeria monocytogenes is a bacterium responsible for the infection known as listeriosis. The pathogen can be contracted from various sources, but food is the most common of all. Soft cheese, milk that has not undergone pasteurization, dairy products, uncooked, unwashed vegetables, as well as beef and poultry that are not maintained in the correct circumstances are substrates on which listeria can ideally reproduce. Its proliferation is facilitated in cold temperatures (4-10°C) and ingestion of infected products suffices for the infection to be initiated.

The bacterium is facultative anaerobic, motile and does not form spores. Direct transmission from mother to child during labor or pregnancy is possible.

Listeriosis is a rather rare medical entity. it is believed that only 3 cases per million people are diagnosed each year. Paradoxically, 700 individuals were found to have listeriosis in the USA in the year 2004.

The infection's frequency may be scarce, but it escalates amongst particular groups which display a diminished immunological response. Pregnant women are more susceptible to Listeria monocytogenes, as the prevalence seems to be approximately 12 per 100,000 women. Elderly individuals and other patients whose immune system has been weakened due to various causes (pharmacologic treatment, congenital diseases, other co-infections) are in a greater risk of contracting the bacterium too. In fact, mortality seemed to be particularly high between 2009 and 2011; every patient who succumbed due to listeriosis-induced complications belonged to one of the aforementioned high-risk groups [3].

With regard to newborns, the infection can start to be symptomatic within less than 5 days after birth (early onset) or within more than 5 days after birth, in which case it is termed as late onset. The early onset infection type is accompanied by an extremely high mortality rate amongst newborn children as well [4], a rate that is believed to reach up to 40%.

Any individuals can be infected with Listeria monocytogenes after ingesting food which is infected with the pathogen, such as inappropriately preserved poultry or meat in general, raw vegetables that have not been adequately cleaned and seafood.

Patients are expected to develop the first symptoms and sings within 1 day, with reference to a food poisoning, and after an average period of a month, when we refer to meningitis, encephalitis or bacteremia.

Concerning the acquisition of the microbe by a newborn baby, this can occur via two pathways: either by transplacental transmission, or by an infected birth canal (vaginal canal) [5] [6], although the latter way is less common.

The infection is initiated with the translocation of bacteria from the intestine to the visceral organs, with the liver being the first target. Bacterial proliferation occurs within the hepatic region until an immunological reaction starts. In otherwise healthy individuals, the infection is self limited; since Listeria monocytogenes is often found in products one consumes, the organism possesses memory T cells against the microorganism. Individuals belonging to the high-risk groups, however, exhibit a decline in their defense mechanisms, which leads to the system's inability to hinder the profound reproduction of bacteria in the liver. Thus, severe complications and extensive disease are rendered possible.

It is widely known that all types of products an individual can eat contain a certain number of Listeria pathogens, especially processed products [10]. The most common food products associated with a Listeria infection include soft cheeses, processes products that have not received the necessary degree of sterilization or preservation, wrong pasteurization techniques and vegetable products that are consumed without rinsing them before.

All individuals can be protected from such an infection, by following basic hygienic advice with regard to the maintenance and cooking of food, such as cooking meat products for a considerable amount of time, not allowing for uncooked meat to be in contact with cooked products and washing one's hands after touching uncooked meat. Surfaces have to be adequately cleaned after raw poultry or meat in general have been in contact with them. High-risk people such as pregnant women should not consume soft cheese or delicatessen products during pregnancy, unless the latter have been heated in high temperatures.

Listeriosis is an infection that is not frequently diagnosed in everyday clinical practice. The etiologic agent behind this infection is Listeria monocytogenes, which is a facultative anaerobic bacterium [1] [2]. It is usually isolated from contaminated food, soil, wood and decaying natural materials. It has also been found in processed meat products, dairy products, raw vegetables that have not been cleaned, and seafood. Listeriosis is particularly common amongst women who are expecting, older patients and individuals with a dysfunctional immunological response.

In some occasions, listeriosis can cause a potentially lethal type of food poisoning; the most dangerous complication is the expansion of the infection to the brain. It has been estimated that listeriosis-induced death occurs in approximately 1/3 of the patients.

Listeriosis is a type of infection caused by a specific bacterium, Listeria monocytogenes. L. monocytogenes typically resides in various locations: the soil, raw vegetables, uncooked meat or meat preserved under the wrong circumstances, milk that has not been pasteurized well or dairy products produced from this milk. Soft cheeses are more frequently linked to listeria infections in comparison to other cheese types and ready delicatessen meals can also contain the bacteria, if their processing has not been conducted in the correct way.

Listeriosis can cause two types of symptoms, depending on how strong the patient's immune system is. In healthy individuals, it causes food poisoning with relevant symptomatology, such as diarrhea, vomiting and nausea. People whose immune system is weakened, however, tend to develop severe disease, including meningitis, encephalitis (infection of the brain matter) and sepsis, namely the spreading of the bacteria in the bloodstream. People who are more susceptible to a severe listeria infection include newborn kids whose immune system has not yet matured, older people, pregnant women and generally immunocompromised patients, either due to a congenital disease, transplantation etc. These groups suffer from an infection of the meninges, brain and an extensive infection of the internal organs which can possibly lead to death.

Listeriosis can be diagnosed when the Listeria pathogen is detected in the blood, the spinal fluid, the joint or pleural fluid as well as in other locations. It is a treatable condition, for which antibiotics such as ampicillin or gentamicin are used.

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