Cows and chickens fed antibiotics to make them grow faster. Humans who beg their doctors for antibiotics to treat colds and other viral ills that will go away on their own, or who don't finish the course of antibiotics their doctor prescribed to treat genuine bacterial infections.

Related: Do You Really Need That Antibiotic?

All of these factors contribute to drug-resistant germs, which have evolved over time the power to elude the antibiotics we used to use against them.

According to the CDC, at least 2 million Americans develop antibiotic-resistant infections — such as MRSA — annually, and 23,000 people a year die as a result.

You can do your part to stop more bacteria strains from become antibiotic resistant by learning about illnesses that don't normally require antibiotics and what you can do to relieve your virus symptoms naturally. (Antibiotics don't treat viruses.)

The Centers for Disease Control and Prevention (CDC) outlined in a 2013 report the top 18 drug-resistant threats to the United States, divided the germs into three threat levels: urgent, serious and concerning. Here's the full list.

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Urgent

  • Clostridium difficile (C. diff), which causes life-threatening diarrhea
  • Carbapenem-Resistant Enterobacteriaceae (CRE), which causes bloodstream infections in hospitalized patients
  • Neisseria gonorrhoeae, which causes gonorrhea

Serious

  • Acinetobacter, a gram-negative bacteria that causes pneumonia or bloodstream infections among critically ill patients
  • Campylobacter, which usually causes diarrhea (often bloody), fever, and abdominal cramps, and sometimes causes serious complications such as temporary paralysis
  • Candida, yeasts that cause fungal infections, including blood infections
  • Extended-spectrum Enterobacteriaceae. These germs contain enzymes that allow the bacteria to resist strong antibiotics.
  • Vancomycin-resistant enterococci (VRE), intestinal and skin bacteria that can cause serious infections anywhere in the body
  • Multi-drug resistant Pseudomonas aeruginosa, a common cause of healthcare-associated infections including pneumonia, bloodstream infections, urinary tract infections and surgical site infections
  • Non-typhoidal salmonella, which causes diarrhea (sometimes bloody), fever, and abdominal cramps
  • Salmonella serotype Typhi, which causes typhoid fever
  • Shigella, which causes diarrhea (sometimes bloody), fever, and abdominal pain
  • Methicillin-resistant Staphylococcus aureus (MRSA), which causes a range of illnesses, from skin and wound infections to pneumonia and bloodstream infections
  • Streptococcus pneumoniae, the leading cause of bacterial pneumonia and meningitis in the United States
  • Mycbacterium tuberculosis, which causes tuberculosis, one of the most common infectious diseases and a frequent cause of death worldwide

Related: Having Surgery? 8 Ways to Avoid a Hospital Infection

Concerning

  • Staphylococcus aureus, a bacterium that can enter the body during medical procedures
  • Erythromycin-Resistant Group A Streptococcus, which causes strep throat, necrotizing fasciitis (“flesh-eating” disease), scarlet fever, rheumatic fever and skin infections such as impetigo
  • Clindamycin-Resistant Group B Streptococcus, a type of bacteria that can cause severe illness in people of all ages

Related: What Do Gram-Negative and Gram-Positive Mean?

Learn more about antibiotic-resistant germs in the infographic below.

world antibiotic(Photo: CDC)