What are bacterial infections?

A bacterium is a single, but complex, cell. It can survive on its own, inside or outside the body.

Most bacteria aren’t harmful. In fact, we have many bacteria on and inside our body, especially in the gut to help digest food. But some bacteria can cause infections. Bacterial infections can affect the throat, lungs, skin, bowel and many others parts of the body. Many are mild; some are severe.

Examples of bacterial infections include whooping cough, strep throat, ear infection and urinary tract infection (UTI).

What are the symptoms of a bacterial infection?

The symptoms of a bacterial infection will depend on the location of the infection and the type of bacteria.

There are some general signs of bacterial infection:

• fever
• feeling tired or fatigued
• swollen lymph nodes in the neck, armpits, groin or elsewhere
• headache
• nausea or vomiting

What causes bacterial infections?

A bacterial infection occurs when bacteria enter the body, increase in number, and cause a reaction in the body. Bacteria can enter the body through an opening in your skin, such as a cut or a surgical wound, or through your airway and cause infections like bacterial pneumonia.

When should I see my doctor?

Signs that you may have a bacterial infection and should see doctor include:

• difficulty breathing
• a persistent cough, or coughing up pus
• unexplained redness or swelling of the skin
• a persistent fever
• frequent vomiting and trouble holding liquids down
• blood in urine, vomit or poo (stool)
• severe stomach pain or severe headache
• a cut or burn that is red or has pus

What are the complications of bacterial infections?

It’s important to seek treatment because an untreated bacterial infection can lead to serious problems.

For example, an untreated infected cut can cause cellulitis and a life-threatening condition called sepsis.

Sepsis (also known as 'septicaemia' or 'blood poisoning') is a serious blood infection that can lead to shock, organ failure and death if it’s not treated quickly.

Sepsis is always a medical emergency. Seek immediate medical attention if you have any of the following:

• fever
• chills
• uncontrolled shaking
• rapid breathing and heart rate
• tiredness
• headaches

How are bacterial infections treated?

Most bacterial infections can be effectively treated with antibiotics. They either kill bacteria or stop them multiplying. This helps the body’s immune system to fight the bacteria.

Your doctor’s choice of antibiotic will depend on the bacteria that is causing the infection. Antibiotics that work against a wide range of bacteria are called broad-spectrum antibiotics.

Antibiotic resistance is a growing problem so antibiotics may be prescribed only for serious bacterial infections.

How can bacterial infections be prevented?

Bacterial infections can be highly contagious, so you need to take special care to avoid spreading infections by washing hands, covering up when sneezing and coughing, and not sharing cups and drink bottles.

Resources and support

If you think you may have a bacterial infection, use healthdirect's online Symptom Checker.