Types of Infections & Treatments

About Listeriosis

Listeriosis is a type of serious bacterial infection caused by eating food contaminated by the bacteria known as Listeria monocytogenes.

Causative Agent:

Listeria monocytogenes.


The infection is seen worldwide and usually sporadic with outbreaks occasionally caused by contaminated food. The infection is usually mild in healthy individuals but can have serious consequences in some patient subgroups : viz: pregnant women, elderly patients, and immunocompromised patients. The incidence increases in those more than 50 years of age. Infection in pregnancy can be a mild disease for the mother but can result in fetal loss, still births, premature labour and severe neonatal sepsis of the newborne. Infection in immunocompromised individuals can result in serious disease including meningitis, brainstem encephalitis and strokes, resulting in death. It is also more likely in patients with liver, renal disease, diabetes and alcoholism.

Implicated Food:

Screening for TB is usually done if you are exposed to an index patient with pulmonary tuberculosis. Usually, the index patient will be a household contacts or work colleague sharing the same office area. First year university students who come from countries endemic with tuberculosis may also be screened for TB upon entry to the university. In addition, screening for TB may be a company policy for health care workers and expatriate staff posted to a country endemic for tuberculosis.

The tests that are usually done are the tuberculin skin test (TST) and the interferon-gamma release assays (IGRA) such as the Quantiferon TB test and the T-spot TB test. These tests indirectly measure TB infection by measuring the immune response to TB proteins. “Reactive tests” indicate that an individual has been exposed to TB. These tests are imperfect and each of them has false positive and false negative testing rates. These tests also cannot be used to determine if an individual who has been exposed to TB will progress to develop active disease. In addition, the tests cannot distinguish between latent tuberculosis and active tuberculosis.

Clinical Presentation:

Can present with the following syndromes :

Mild flu-like illness


Meningo-encephalitis / stroke

Neonatal sepsis of newborne

Mild cases are usually seen in otherwise healthy people and can present like a flu-like illness with fever, muscle aches, nausea and diarrhoea. Meningitis can be severe and present as headaches, fever, seizures or drowsiness. It can also present as a gastroenteritis with nausea, vomiting and diarrhoea.


The diagnosis can be confirmed by isolation of the bacteria by culture in the blood, stools or cerebrospinal fluid depending on the specimens obtained based on the syndrome.


Usually with antibiotics. Penicillins or sulphur drugs alone or in combination can be used for treatment.


  1. Adopt eating safe food practice i.e. eating cooked food, stored properly and consuming only pasteurised diary produce
  2. Do not mix cooked and raw food, use different cutting boards and knives and store them apart in the fridge
  3. Pregnant and immunocompromised patients should not consume undercooked or raw food or unpasteurised diary food.
  4. Practice food and water hygiene

There is no place for antibiotic prophylaxis and there is no vaccine available for this infection.

Points to Note:

HIV is considered to be a chronic infection and at this time, there is no known drug (s) that can eradicate the virus. There are several reports of “cure” but these are very rare cases and they are “1 in many millions’’ occurrences.

HIV is a notifiable disease in Singapore. Do not worry about restriction of travel if you are a Singaporean, the notification is for statistics purposes. However, if you are a foreigner, you may face a travel entry ban unless your physician applies for a permit for you to re-enter Singapore for treatment.
There are also anonymous testing facilities in Singapore if you are concerned about HIV notification.

For more information, please see MOH ( Ministry of Health ) or HPB ( Health Promotion Board ) websites.

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