Bacterial infections (2024)

Key facts

  • Not all bacteria are harmful.
  • Bacterial infections are one cause of infectious diseases.
  • Serious bacterial infections can be treated with antibiotics.
  • Antibiotic resistance is a serious problem.

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 inside our body and on our skin. Bacteria in our intestines (gut) help us to digest our food.

But some bacteria can cause infections. Bacterial infections can affect many parts of your body, including your:

  • throat
  • lungs
  • skin
  • bowel

Many infections are mild, but some are severe.

Some examples of bacterial infections are:

  • Legionnaires’ disease
  • meningococcal disease
  • Q fever
  • strep throat
  • tuberculosis (TB)
  • whooping cough (pertussis)

Other causes of infectious diseases are viruses, parasites and fungi.

What are the symptoms of a bacterial infection?

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

There are some general signs of bacterial infection:

  • fever
  • feeling tired
  • swollen lymph nodes in your neck, armpits, groin or elsewhere
  • headache
  • nausea or vomiting
CHECK YOUR SYMPTOMS — Use the Symptom Checker and find out if you need to seek medical help.

What causes bacterial infections?

Bacterial infections occur when bacteria enter your body. Once in your body they increase in number. This causes an immune reaction in your body.

Bacteria can enter your body through:

  • a cut on your skin
  • eating or drinking contaminated food or water
  • breathing in droplets from an infected person
  • touching dirty surfaces and then touching your eyes, nose, or mouth

Bacteria can also be transmitted by contact with blood and other bodily fluids.

Bacterial infections and weather events

The risk of getting a bacterial infection increases when you are in contact with flood water. Flood water can come from storms or cyclones.

Touching items affected by flooding can also increase your risk of bacterial infection. You should avoid contact with flood water and practice good hand hygiene. Wash your hands with soap and clean water. If clean water isn’t available, use hand sanitiser.

When should I see my doctor?

Signs that you have a bacterial infection depend on the type of bacteria and the part of your body that is infected. You should see your doctor if you have:

  • a persistent fever or chills
  • severe headache or neck stiffness
  • eye redness and crusting (pus)
  • persistent ear pain or wetness (discharge)
  • persistent facial pain and runny nose
  • difficulty breathing
  • a persistent cough, or coughing up blood or pus
  • frequent vomiting and trouble holding liquids down
  • severe stomach pain
  • blood or mucus in your poo (stool)
  • discomfort when urinating (doing a wee) or urine that is smelly, cloudy or contains blood
  • any abnormal genital discharge
  • unexplained skin redness or swelling
  • a skin wound that is red, hot, swollen, or has pus
  • a rash that doesn’t fade when you press it
  • difficulty eating or drinking
  • unexplained weight loss
FIND A HEALTH SERVICE — The Service Finder can help you find doctors, pharmacies, hospitals and other health services. ASK YOUR DOCTOR — Preparing for an appointment? Use the Question Builder for general tips on what to ask your GP or specialist.

How are bacterial infections treated?

Serious bacterial infections can be effectively treated with antibiotics. These medicines either kill the bacteria or stop them multiplying. This helps your body’s immune system fight the bacteria.

Your doctor’s choice of antibiotic will depend on the bacteria that is causing your infection.

Antibiotics that work against a wide range of bacteria are called broad-spectrum antibiotics.

Antibiotic resistance is a growing problem so antibiotics must always be used appropriately and as prescribed.

How can bacterial infections be prevented?

Bacterial infections can be highly contagious. Bacterial infections are spread between people through:

  • coughing
  • sneezing
  • vomiting
  • bodily fluids, from sex or sharing dirty needles

You need to take special care to avoid spreading infections by:

  • washing your hands properly
  • covering up when sneezing and coughing
  • not sharing cups and drink bottles
  • having safe sex
  • not sharing needles

Complications of bacterial infections

It’s important to seek treatment because untreated bacterial infections can lead to serious problems. For example, an untreated infected cut can cause cellulitis, a spreading skin infection.

Untreated bacterial infections can sometimes lead to serious, life-threatening conditions.

  • Septicaemia is a serious blood infection. It is when bacteria enter the bloodstream and cause blood poisoning.
  • Sepsis is a condition that happens when the body damages its own tissues in response to a bad infection. Sepsis can cause shock, organ failure and death if it’s not treated quickly.

Sepsis is a medical emergency and can be fatal if not treated quickly. If you suspect you or someone else has sepsis, call triple zero (000) for an ambulance.

Ask your doctor ‘Could this be sepsis?’ if:

  • you are feeling very unwell
  • you are not getting better from a generalised illness
  • you are quickly getting worse
  • there is any chance of an infection
  • you are more concerned about your child than you normally are when they are sick

Resources and support

You can download the app Could this be sepsis? from the Australian Sepsis Network (ASN), to check your symptoms.

You can find out more about what Australia is doing to limit antimicrobial resistance here.

You can call the healthdirect helpline on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak with 24 hours a day, 7 days a week.

Bacterial infections (2024)


Bacterial infections? ›

Bacterial infections are diseases that can affect your skin, lungs, brain, blood and other parts of your body. You get them from single-celled organisms multiplying or releasing toxins in your body. Common bacterial diseases include UTIs, food poisoning, STIs and some skin, sinus and ear infections.

What are the five most common bacterial infections? ›

There are skin infections, respiratory tract infections, the dreaded “gastro” or food poisoning, sexually transmitted diseases and urinary tract infections.

Can bacterial infections go away on their own? ›

“Some bacterial infections get better on their own, but that's rare,” Dr. Price said. Most of the time, your doctor will prescribe an antibiotic. If that's the case, it's essential to take the entire course—even if you feel better, you need to take all of your medication to make sure you clear the infection.

What is the best way to fight a bacterial infection? ›

Most bacterial diseases can be treated with antibiotics, although antibiotic-resistant strains are starting to emerge.

What happens to your body when you are infected by bacteria? ›

Sometimes bacteria multiply so rapidly they crowd out host tissues and disrupt normal function. Sometimes they kill cells and tissues outright. Sometimes they make toxins that can paralyze, destroy cells' metabolic machinery, or precipitate a massive immune reaction that is itself toxic.

Can your body rid itself of a bacterial infection? ›

Not all bacterial infections need to be treated — some go away on their own. When you do need treatment, healthcare providers use antibiotics. Depending on where your infection is and how serious it is, antibiotics can be prescribed as: Oral medication (pills).

Can you get rid of a bacterial infection without antibiotics? ›

However, Some bacterial infections don't necessarily require antibiotics because they tend to resolve independently with basic at-home comfort care measures.

What is the most serious bacterial infection? ›

Most Deadly Bacterial Infections
  • Botulism.
  • Pseudomonas Infection.
  • MRSA Infection.
  • E.Coli Infection.
  • Meningitis.
  • Gonorrhea.
  • Bubonic Plague.
  • Syphilis.

What are signs your body is fighting a virus? ›

Symptoms of a viral infection depend on where you're infected, but some common ones include: Flu-like symptoms: fever, head and body aches, fatigue. Upper respiratory symptoms: sore throat, cough, sneezing. Digestive symptoms: nausea, vomiting, diarrhea.

Is a bacterial infection contagious? ›

Many bacterial infections are contagious, meaning that they can be transmitted from person to person. There are many ways this can occur, including: close contact with a person who has a bacterial infection, including touching and kissing.

What are the signs of sepsis? ›

  • Chills.
  • Confusion or delirium.
  • Fever or low body temperature (hypothermia)
  • Lightheadedness due to low blood pressure.
  • Rapid heartbeat.
  • Skin rash or mottled skin.
  • Warm skin.

How many days does bacterial infection last? ›

Bacterial infections may be the result of "secondary infection" (meaning that the virus initiated the process but a bacteria followed) when the: Symptoms persist longer than the expected 10-14 days a virus tends to last.

What is the hardest bacterial infection to get rid of? ›

Methicillin-Resistant Staphylococcus Aureus

This type of bacteria is resistant to many antibiotics, including methicillin. Most methicillin-resistant Staphylococcus aureus, or MRSA, infections contracted outside of a hospital are skin infections.

What kills bacteria most rapidly? ›

The World Health Organization (WHO) notes that bacteria are rapidly killed at temperatures above 149°F (65°C). This temperature is below that of boiling water or even a simmer.

What is the closest thing to antibiotics over the counter? ›

What Is the Closest Thing to Antibiotics Over the Counter?
  • Bacitracin (Neosporin)
  • Benzoyl Peroxide (Polysporin)
  • Neomycin (Neosporin + Pain Relief)
  • Polymyxin (Proactiv)
Mar 11, 2022

How do you know if your body is fighting an infection? ›

Know the Signs and Symptoms of Infection
  • Fever (this is sometimes the only sign of an infection).
  • Chills and sweats.
  • Change in cough or a new cough.
  • Sore throat or new mouth sore.
  • Shortness of breath.
  • Nasal congestion.
  • Stiff neck.
  • Burning or pain with urination.

How does a bacterial infection make you feel ill? ›

But infectious bacteria can make you ill. They reproduce quickly in your body. Many give off chemicals called toxins, which can damage tissue and make you sick.

How do you know if you have a bacterial cold or virus? ›

You may have developed a bacterial infection if: symptoms last longer than 10 to 14 days. symptoms continue to get worse rather than improve over several days. you have a higher fever than normally observed with a cold.

How does a woman know if she has a bacterial infection? ›

Symptoms of bacterial vaginosis include: Thin, vagin*l discharge that may be gray, white or green. Foul-smelling, "fishy" vagin*l odor.


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