Antimicrobial resistance (AMR) is when microbes are less treatable with one or more medication used to treat or prevent infection. This makes these medications less effective in both treating and preventing infection. Resistant microbes may require other medications or higher doses – often with more side effects, some of which may be life threatening on their own. Some infections become completely untreatable due to resistance. All classes of microbes develop resistance: fungi – antifungal resistance, viruses – antiviral resistance, protozoans – antiprotozoal resistance, and bacteria – antibiotic resistance. Microbes which are resistant to multiple antimicrobials are termed multidrug resistant (MDR) (or, sometimes in the lay press, superbugs). Antimicrobial resistance is a growing problem in the world, and causes millions of deaths every year.Antibiotics should only be used when needed and only when prescribed. Health care providers should try to minimize spread of resistant infections by using proper sanitations techniques including handwashing or disinfecting between each patient. Prescribing the correct antibiotic is important and doses should not be skipped. The shortest duration needed should be used. Narrow-spectrum antibiotics should be used rather than broad-spectrum antibiotics when possible. Cultures should be taken before treatment when indicated and treatment potentially changed based on the susceptibility report.Some organisms are naturally resistant but the term most often refers to acquired resistance, which can be a result of either new mutations or transfer of resistance genes between organisms. The increasing rates of antibiotic resistant infections are caused by antibiotic use from human and veterinary medicine. Any use of antibiotics can increase selective pressure in a population of bacteria, promoting resistant bacteria and causing vulnerable bacteria to die. As resistance to antibiotics becomes more common there is greater need for alternative treatments. Call for new antibiotic therapies have been issues, but there is continuing decline in the number of approved drugs. Infection by resistant microbes may occur outside of a healthcare institution or within a healthcare institution. Common types of drug-resistant bacteria include: methicillin-resistant Staphylococcus aureus (MRSA), vancomycin-resistant S. aureus (VRSA), extended spectrum beta-lactamase (ESBL), vancomycin-resistant Enterococcus (VRE), multidrug-resistant A. baumannii (MRAB).Antibiotic resistance is a serious and growing global problem: a World Health Organization (WHO) report released April 2014 stated, ""this serious threat is no longer a prediction for the future, it is happening right now in every region of the world and has the potential to affect anyone, of any age, in any country. Antibiotic resistance—when bacteria change so antibiotics no longer work in people who need them to treat infections—is now a major threat to public health."" There have been increasing public calls for global collective action to address the threat, including a proposal for an international treaty on antimicrobial resistance. Antibiotic resistance is not properly mapped across the world, but the countries that are affected the most are poorer countries with already weaker healthcare systems.