What is Anti-Microbial Resistance?

Antimicrobial resistance (AMR) is when microbes (bacteria, parasites, viruses and fungi) are less treatable with one or more drugs used to treat infection, where microbes resist the effect of drugs and are not killed and their growth is not stopped. This makes these medications less effective in both treating and preventing infection. Although some people are at greater risk than others, no one can completely avoid the risk of antibiotic-resistant infections. Infections with resistant organisms are difficult to treat, requiring costly and sometimes toxic alternatives. Microorganisms inevitably find ways of resisting the drugs developed by humans, which is why aggressive action is needed to keep new resistance from developing and to prevent the resistance that already exists from spreading. It is an increasingly serious threat to global public health that requires action across all government sectors and society. New resistance mechanisms emerge and spread globally.

Some Key facts about AMR: (Ref: http://www.who.int/mediacentre/factsheets/fs194/en/)

•  In 2012, WHO reported a gradual increase in resistance to HIV drugs. Since then, further increases in resistance to first-line treatment drugs were reported, which might require using more expensive drugs in the near future.
• In 2013, there were about 480 000 new cases of multidrug-resistant tuberculosis (MDR-TB). Extensively drug-resistant tuberculosis (XDR-TB) has been identified in 100 countries. MDR-TB requires treatment courses that are much longer and less effective than those for non-resistant TB.
• Resistance to the best available treatment for falciparum malaria, artemisinin-based combination therapies (ACTs), has been reported.
• Huge proportions of antibiotic resistance in bacteria that cause common infections (e.g. urinary tract infections, pneumonia, bloodstream infections) are being reported in all regions of the world.
• A high percentage of hospital-acquired infections are caused by highly resistant bacteria such as methicillin-resistant Staphylococcus aureus(MRSA) or multidrug-resistant Gram-negative bacteria.
• Treatment failures due to resistance to treatments of last resort for gonorrhoea (third-generation cephalosporins) have been reported from various countries.
• Patients with infections caused by drug-resistant bacteria are generally at increased risk of worse clinical outcomes and death, and consume more health-care resources than patients infected with the same bacteria that are not resistant.

Present situation

Resistance in bacteria

WHO’s 2014 report on global surveillance of antimicrobial resistance revealed that antibiotic resistance is no longer a prediction for the future; it is happening right now, across the world, and is putting at risk the ability to treat common infections in the community and hospitals. Without urgent, coordinated action, the world is heading towards a post-antibiotic era, in which common infections and minor injuries, which have been treatable for decades, can once again kill.

• Treatment failure to the drug of last resort for gonorrhoea – third-generation cephalosporins – has been confirmed in several countries. Untreatable gonococcal infections result in increased rates of illness and complications, such as infertility, adverse pregnancy outcomes and neonatal blindness, and has the potential to reverse the gains made in the control of this sexually transmitted infection.
• Resistance to one of the most widely used antibacterial drugs for the oral treatment of urinary tract infections caused by E. coli – fluoroquinolones – is very widespread.
• Resistance to first-line drugs to treat infections caused by Staphlylococcus aureus – a common cause of severe infections acquired both in health-care facilities and in the community – is also widespread.
• Resistance to the treatment of last resort for life-threatening infections caused by common intestinal bacteria – carbapenem antibiotics – has spread to all regions of the world. Key tools to tackle antibiotic resistance – such as basic systems to track and monitor the problem – reveal considerable gaps. In many countries, they do not even seem to exist.

Resistance in tuberculosis

In 2013, there were an estimated 480 000 new cases of MDR-TB in the world. Globally, 3.5% of new TB cases and 20.5% of previously treated TB cases are estimated to have MDR-TB, with substantial differences in the frequency of MDR-TB among countries. Extensively drug-resistant TB (XDR-TB, defined as MDR-TB plus resistance to any fluoroquinolone and any second-line injectable drug) has been identified in 100 countries, in all regions of the world.

Resistance in malaria

The emergence of P. falciparum multidrug resistance, including resistance to ACTs, in the Greater Mekong subregion is an urgent public health concern that is threatening the ongoing global effort to reduce the burden of malaria. Routine monitoring of therapeutic efficacy is essential to guide and adjust treatment policies. It can also help to detect early changes in P. falciparum sensitivity to antimalarial drugs.

Resistance in HIV

HIV drug resistance emerges when HIV replicates in the body of a person infected with the virus who is taking antiretroviral drugs. Even when antiretroviral therapy (ART) programmes are very well-managed, some degree of HIV drug resistance will emerge.

Available data suggest that continued expansion of access to ART is associated with a rise in HIV drug resistance. In 2013, 12.9 million people living with HIV were receiving antiretroviral therapy globally, of which 11.7 million were in low- and middle-income countries.

HIV drug resistance may rise to such a level that the first-line and second-line ART regimens currently used to treat HIV become ineffective, jeopardizing people’s lives and threatening national and global investments in ART programmes.

As of 2010, levels of HIV drug resistance among adults who had not begun treatment in countries scaling up ART were found to be about 5% globally. However, since 2010, there are reports suggesting that pre-treatment resistance is increasing, peaking at 22% in some areas.

Continuous surveillance of HIV drug resistance is of paramount importance to inform global and national decisions on the selection of first and second-line ART and to maximize overall population level treatment effectiveness.

Resistance in influenza

Over the past 10 years, antiviral drugs have become important tools for treatment of epidemic and pandemic influenza. Several countries have developed national guidance on their use and have stockpiled the drugs for pandemic preparedness. The constantly evolving nature of influenza means that resistance to antiviral drugs is continuously emerging.

By 2012, virtually all influenza A viruses circulating in humans were resistant to drugs frequently used for the prevention of influenza (amantadine and rimantadine). However, the frequency of resistance to the neuraminidase inhibitor oseltamivir remains low (1-2%). Antiviral susceptibility is constantly monitored through the WHO Global Surveillance and Response System.