Bacterial Infection

Bacterial infections are illnesses or skin conditions that you get from bacteria. Bacteria are single-celled organisms that can multiply quickly in your body and make you sick. Some also release harmful toxins.

There are millions of bacteria that live all around us — in soil and water, and on surfaces where we live and work. There are even millions of bacteria that live on your skin and inside your body. Most bacteria aren’t harmful, and many are even helpful. But even the helpful ones can hurt you if they grow in your body where they’re not supposed to.

Bacteria can enter your body through a break in your skin, bug bites, or contaminated food, water or surfaces. Almost any part of your body can get a bacterial infection.

Types

Bacteria can cause many types of infections, depending on how you’re exposed and what part of your body it infects. Some common types of bacterial infections include:

• Food poisoning (gastroenteritis)
• Some skin, ear or sinus infections
• Some sexually transmitted infections (STIs)
• Bacterial pneumonia
• Most urinary tract infections (UTIs)

Examples of bacterial infections

Common bacterial infections include:

• Bacterial vaginosis, an overgrowth of bacteria in your vagina
• Campylobacter and Salmonella infections, common types of food poisoning
• C. diff, an infection in your intestines
• Cellulitis, boils and impetigo, types of skin infections
• Chlamydia and gonorrhea, types of sexually transmitted infections
• E. coli, a common cause of urinary tract infections
• Lyme disease, a disease spread by ticks
• Pneumococcal disease, including ear and sinus infections and some types of pneumonia
• Strep throat, a common infection in kids that causes a sore throat

Symptoms of bacterial infections

Symptoms depend on where in your body the infection is. Common symptoms of bacterial infections include:

• Fever
• Chills
• Fatigue (tiredness)
• Headache

Additional symptoms can include:

• Skin: Redness, blisters, ulcers, and swollen or painful skin
• GI tract: Diarrhea, stomach pain, nausea and vomiting
• Lungs: Cough, shortness of breath, chest pain and phlegm (sputum)
• Lining around your brain (meningitis): Neck stiffness, nausea or vomiting, confusion and sensitivity to light
• Sepsis or bacteremia (bloodstream infection spreading to your organs): High fever, weakness, sweating and low blood pressure
• Heart (endocarditis): High fever, chest pain, night sweats, shortness of breath, cough, and muscle and joint pain
• Urinary tract or genitals: Burning or pain when you pee, discharge from your penis or vagina, increased need to pee and painful intercourse

Bacterial infection causes

Many kinds of bacteria cause infections. You usually get an infection when bacteria enter your body through your mouth, nose or eyes, or through a cut in your skin. Sometimes, bacteria that normally live on your skin or in your body get into places they’re not supposed to (like through an injury) and reproduce.

Bacteria can hurt your body either by reproducing or by releasing poisons (toxins) that damage your cells.

Transmission

Different bacterial infections spread in different ways. Most have one specific way that they’re most likely to spread, but they may spread other ways, too. Common modes of transmission include:

• Airborne or droplet: Bacteria that spread through contaminated dust or droplets of water, or infected mucus (like phlegm or snot). Common infections that spread this way include strep throat and pertussis (whooping cough).
• Contact: Bacteria that spread through contact with infected skin, body fluids or mucous membranes (direct contact) or through contaminated objects and surfaces (indirect contact). Skin infections and bacterial STIs spread mainly through direct contact. But many other types of bacteria can spread through indirect contact, too.
• Vector: Bacteria that spread through bug bites. Diseases like Lyme disease and shigellosis spread through vectors (mosquitoes, ticks, fleas and other bugs).
• Vehicular: Bacteria that spread through contaminated water or food (the “vehicle” of transmission). Examples include E. coli, Campylobacter and Salmonella.

How do you get a bacterial infection?

Common ways you can get bacterial infections include:

• Eating or drinking contaminated food or water
• Eating or drinking unpasteurized dairy products
• Antibiotic use, which can kill the good bacteria that usually fight off bad bacteria
• From contaminated surfaces
• From other people (through coughing or close contact)
• From getting contaminated water into your lungs (aspirating)
• Through oral, anal or vaginal sex
• Through contaminated dirt (soil)
• From a bite from an infected tick, mosquito or flea
• From surgery or intubation (tube in your throat)

Are bacterial infections contagious?

Yes, many bacterial infections are contagious from person to person, including pertussis, tuberculosis, strep throat, meningococcal disease, STIs and MRSA. Infections you get from food, mosquitoes or ticks are usually not contagious.

Risk factors

Anyone can get a bacterial disease, and most of us will at some point in our lives. You’re at higher risk if you have:

• Diabetes
• A weakened immune system
• An open wound
• Had surgery recently

Complications

Not all bacterial infections are serious. But some can lead to sepsis, a severe reaction to an infection. Sepsis causes organ damage and can be fatal.

How doctors diagnose bacterial infections

A healthcare provider diagnoses a bacterial infection by listening to your symptoms, examining you and taking samples to test for bacteria. They’ll send body fluid or tissue samples to a lab to look for signs of an infection. A lab technician might also try to grow bacteria from your samples.

Types of samples they might take include:

• Skin or other affected tissue
• Blood
• Phlegm (sputum)
• Fluid around your brain and spinal cord (CNS fluid)
• Pee (urine)
• Fluid from your eye (secretions)
• Poop (stool)

If your provider thinks that you have bacteria in your lungs, brain or another internal organ, they might get X-rays, ultrasound images, MRI scans or CT scans to look for signs of infection.

How are bacterial infections treated?

Healthcare providers treat bacterial infections with antibiotics. Depending on where your infection is and how serious it is, antibiotics can be prescribed as:

• Oral medication (pills)
• IV medication, given to you directly into a vein at a doctor’s office or hospital
• Ointment or cream
• Eye drops

Sometimes, certain antibiotics stop working and don’t kill or slow down bacteria (antibiotic resistance). Because of this, healthcare providers are careful about when and how they prescribe antibiotics. They only prescribe them if they think they’ll help you. It’s important for you to take any medication as prescribed, even if you start to feel better.

Some infections don’t need treatment. It’s always best to check with a provider, though.

When should I see my healthcare provider?

Contact a healthcare provider if you have symptoms of a bacterial infection, especially if you’ve had them for more than a couple of days. Make sure to follow up with your provider if you’ve been treating an infection and your symptoms aren’t getting better or are getting worse.

Go to the nearest ER or seek immediate medical attention if you have signs of a serious infection, including:

• High fever (103 degrees Fahrenheit or 39.4 degrees Celsius)
• Confusion or other mental changes
• Neck stiffness with other symptoms of meningitis (headache, nausea, vomiting)
• Low blood pressure

What can I expect if I have a bacterial infection?

What to expect depends on what kind of bacterial infection you have. You can treat less serious bacterial infections with medication at home. Others require a hospital stay and can cause lasting damage. Bacterial infections in your internal organs or blood can be life-threatening.

Infections that only affect the surface of your skin or mucous membranes (like your throat or intestines) aren’t usually serious. But sometimes, bacteria can spread in your body and cause life-threatening illnesses.

How long do they last?

If you’re prescribed antibiotics for a bacterial infection, you’ll usually have to take them for a week or two. But you’ll probably feel better sooner. Take all your medication as prescribed. Otherwise, you might not get rid of all the bacteria.

Can bacterial infections be prevented?

Ways to reduce your risk of various types of bacterial infections include:

• Get vaccinated: There are vaccines for many bacterial diseases, including tetanus, whooping cough, diphtheria and bacteria that cause certain forms of meningitis (Neisseria meningitides), pneumonia (Streptococcus pneumoniae, Haemophilus influenzae type b) and bloodstream infections.
• Practice good hygiene: This includes maintaining good handwashing habits, wearing clean and dry clothes and not sharing personal items with other people.
• Keep wounds clean: Breaks in your skin allow bacteria to get in. Clean and cover cuts or wounds in your skin.
• Practice safe food habits: This includes storing food properly, heating meat to a temperature that kills bacteria, and washing or peeling fruits and vegetables before eating.
• Practice safe sex: Use a condom or dental dam during any kind of sex.
• Protect yourself from bug bites: Wear protective clothing, use bug spray, and check yourself and your pets for ticks after being outdoors.

What’s the difference between a bacterial infection and viral infection?

Both viruses and bacteria can cause infections that may have similar symptoms. But different organisms cause these infections. Living, single-celled organisms that can reproduce on their own cause bacterial infections.

Viruses — non-living organisms that are made up of genetic information wrapped in a shell — cause viral infections. Viruses always need to infect humans or other living things to create more copies of themselves.

Antibiotics can treat most bacterial infections, but only a few viral infections have medications that treat them.