Find Information About:

Drugs & Supplements

Get information and reviews on prescription drugs, over-the-counter medications, vitamins, and supplements. Search by name or medical condition.

Pill Identifier

Pill Identifier

Having trouble identifying your pills?

Enter the shape, color, or imprint of your prescription or OTC drug. Our pill identification tool will display pictures that you can compare to your pill.

Get Started

My Medicine

Save your medicine, check interactions, sign up for FDA alerts, create family profiles and more.

Get Started

WebMD Health Experts and Community

Talk to health experts and other people like you in WebMD's Communities. It's a safe forum where you can create or participate in support groups and discussions about health topics that interest you.

  • Second Opinion

    Second Opinion

    Read expert perspectives on popular health topics.

  • Community


    Connect with people like you, and get expert guidance on living a healthy life.

Got a health question? Get answers provided by leading organizations, doctors, and experts.

Get Answers

Sign up to receive WebMD's award-winning content delivered to your inbox.

Sign Up

HIV & AIDS Health Center

Select An Article

HIV, AIDS, and Mycobacterium Avium Complex

Font Size

Mycobacterium avium complex (MAC) is a group of bacteria that are related to tuberculosis. These germs are very common in food, water, and soil. Almost everyone has them in their bodies. If you have a strong immune system, they don't cause problems. But they can cause serious illness in people with HIV (human immunodeficiency virus). With the right combination of medications, however, you can prevent or treat MAC. In some cases, you may need lifelong therapy.

How Mycobacterium Avium Complex Develops

With HIV, MAC infection usually happens only after you receive a diagnosis of AIDS (acquired immunodeficiency syndrome) and when CD4 cell counts drop below 50.

MAC is an opportunistic infection that takes advantage of a weakened immune system. It can infect one part of your body, such as your lungs, bones, or intestines. This is called localized infection. It can spread and cause disease throughout your body. This is called disseminated infection.

Symptoms of Mycobacterium Avium Complex

If MAC spreads throughout your body, you may have symptoms such as:

You may develop other problems as well, such as:

Diagnosing Mycobacterium Avium Complex

Many opportunistic infections can cause the same symptoms as MAC. It's important to get a diagnosis to know how best to treat it. In addition to performing a physical exam, your doctor may order lab tests to find the MAC bacteria in samples of:

  • Blood
  • Urine
  • Sputum
  • Bone marrow
  • Tissue

These samples are allowed to grow for several weeks, called a culture. Then a health care provider checks the samples for signs of MAC.

While waiting for the results of the culture, your doctor may conduct other tests, including:

  • Blood tests to check for problems such as anemia
  • Serum alkaline phosphatase, a blood test to check for an enzyme that is often high with MAC
  • Computed tomography (CT) scan of your chest and abdomen to check for problems with lymph nodes or enlargement of the liver or spleen

To diagnose MAC, your doctor may also take a tissue sample and examine it under a microscope (called a biopsy).

Next Article:

Today on WebMD

How much do you know?
contemplative man
What to do now.
Should you be tested?
HIV under microscope
What does it mean?
HIV AIDS Screening
man opening condom wrapper
HIV AIDS Treatment
Discrimination Stigma
Treatment Side Effects
grilled chicken and vegetables
obese man standing on scale
cold sore