The 64-year-old singer was admitted to the intensive care unit (ICU) and had to be intubated after being found unconscious on June 24, according to health news site Healthline.

After several days in the ICU, her health is improving and she was discharged on June 29.

It is unclear what type of bacteria Madonna contracted.

There are several types of infections, ranging from pneumonia and meningitis to skin or soft tissue infections or blood infections.

These infections can have serious health implications, but knowing how to prevent them can significantly reduce your risk, Dr. Norman Ng, an emergency physician at Staten Island University Hospital, told Healthline.

How does this infection spread?

People can get serious infections in a number of different ways.

The first is through direct contact with a sick person or contaminated surface that contains dangerous bacteria, said Dr. Ng. Examples include whooping cough, tuberculosis, strep throat and meningococcal meningitis.

Vectors, such as ticks, fleas, and mosquitoes, can also transmit the bacteria to humans by biting the skin.

Bacteria, including Staphylococcus, Streptococcus, and Pseudomonas, can cause infections after surgical procedures. These bacteria can be transmitted through contaminated surgical instruments or spread into the wound through the air or by infected caregivers.

Another common route is through consuming contaminated food and water. For example, Salmonella can be contracted by eating undercooked meat or food contaminated with feces from infected animals.

Or you can get Listeria by eating raw vegetables, meat, unpasteurized milk or processed foods like cold cuts, which contain the bacteria, according to Healthline.

People at highest risk include people with diabetes, the elderly, pregnant women, young children, and people with weakened immune systems such as those with AIDS, cancer patients, or organ transplant recipients.

Why can infections cause serious illness?

Early signs of infection include fever, nausea and vomiting, rapid heart rate, and unconsciousness.

An infectious disease expert, Dr. Amesh Adalja, senior scholar at the Center for Health Security at Johns Hopkins University (USA), said these symptoms can cause patients to be admitted to the emergency room (ED).

Different sites of infection will cause different symptoms. For example, someone with bacterial pneumonia may have difficulty breathing and need to go to the emergency room, or someone with a bacterial urinary tract infection may have burning when urinating and need to go to the emergency room, Dr. Adalja said.

Patients may also need to be admitted to the ICU if they cannot maintain oxygen levels, blood pressure, or have severe organ damage.

Additionally, in some cases, the infection can spread to the bloodstream and cause sepsis, which may require ICU admission, according to Healthline.

What can I do to prevent infection?

There are some simple steps to reduce your risk of infection and avoid serious complications.

• Limit touching your face and wash your hands frequently
• When going out, apply insect repellent, wear long sleeves and long pants to avoid insect bites, Dr Ng added.
• Handle food properly, such as washing hands before eating and cooking food thoroughly
• Practice proper hygiene, stay home if sick, and wash your hands often to prevent the spread of infections, according to Healthline.