We live in an era in which we depend on antibiotics, and other antimicrobial medicines to treat conditions those decades ago, or even a few years ago in the case of HIV/AIDS, would have proved fatal. When antimicrobial resistance - also known as drug resistance - occurs, it renders these medicines ineffective. For World Health Day 2011, WHO calls for intensified global commitment to safeguard these medicines for future generations? Antimicrobial resistance and its global spread, threatens the continued effectiveness of many medicines used today to treat infectious diseases. WHO also calls on governments and stakeholders to implement the policies and practices needed to prevent and counter the emergence of highly resistant microorganisms.
Antimicrobial agents are medicines used to treat infections caused by micro organisms, including bacteria, fungi, parasites and viruses. The discovery of antimicrobials is one
of the most important advances in health in human history – alleviating suffering from disease and saving billions of lives over the past 70 years. Antimicrobials include antibiotics, chemotherapeutic agents, antifungal, antiparasitic and antiviral medicines.
Most of us live longer and healthier lives today, partly because powerful and effective medicines – known as antimicrobials – are available to treat infectious diseases. Until the discovery and availability of antimicrobials in the 1940s, people died needlessly from infectious diseases. Today, none of us can imagine living in a world without antimicrobials.
Antimicrobial resistance is facilitated by the inappropriate use of medicines, for example, when taking substandard doses or not finishing a prescribed course of treatment. Low-quality medicines, wrong prescriptions and poor infection control also encourage the development and spread of drug resistance. Lack of government commitment to address these issues, poor surveillance and a diminishing arsenal of tools to diagnose, treat and prevent also hinder the control of drug resistance.
Often, antibiotics are administered to patients with bacterial infections. But antibiotics kill a large proportion of various bacteria instead of killing only the bacteria that are responsible for the disease. Misuse of antibiotics promotes emergence of resistant bacteria known as Antimicrobial resistance which is the ability of certain micro-organisms to withstand attack by antimicrobials. And, its uncontrolled rise threatens lives and wastes limited healthcare resources.

Emerging Infectious Diseases
 Emerging infectious diseases are closing, or have the potential to close windows of opportunity for infectious disease eradication or elimination. The eradication of smallpox stands as one of the outstanding achievements in the history of public health. Eradication was achieved because of a worldwide effort that was supported by the necessary political will and human and technical resources. The world took advantage of opportunity for smallpox eradication because a safe vaccine was available.
 In the year that smallpox was declared eradicated, human immunodeficiency virus, HIV, appeared and rapidly colonized Africa and the world. Today, the prevalence of HIV is greater than 25 percent in some adult populations, such as in the Democratic Republic of Congo (formerly Zaire). In the United States, a military recruit who was immunized against smallpox developed generalized vaccinia because he was HIV seropositive, and died. That tragic event highlights the fact that if the global smallpox eradication campaign had been postponed, the world would not have been able to eradicate smallpox as easily as it did before 1980.
 The prevalence of tuberculosis (TB) and multidrug-resistant TB is increasing globally. The emergence of HIV facilitated the resurgence of TB, which provides another example of a case in which an opportunity has been lost. 
 Today, the malaria parasite is resistant to the drugs of choice chloroquine or pyrimethamine-sulfadoxine, or both because of improper treatment. Drug-resistant malaria takes longer to respond to treatment. In addition, the mosquito species that transmit the parasite are resistant to the insecticide that previously controlled them be- cause of the improper use of insecticides and a breakdown of public health infrastructure. A window of opportunity to eliminate malaria and mitigate its impact has been lost as increasing numbers of adults are losing work and more children are dying because of the resurgence of malaria.
 The spread of meningitis may be due to the extreme droughts brought about by changing climate conditions in those areas. The bovine spongiform encephalopathy (BSE) outbreak in cows in the United Kingdom, with the subsequent resulting outbreak among humans of a variant of Creutzfeldt-Jacob disease (vCJD), is an example of carelessness in food-handling practices and public health measures. That is, in the late 1970s the procedures for rendering bone meal and other products from animal carcasses changed. The resultant food products were used in animal feed. However, infectious agents were transmitted through the animal feed from infected carcasses back into ruminants, resulting in the BSE epidemic and the transmission of the BSE agent to humans, resulting in vCJD. At a time when infectious diseases are on the rise when 48 percent of deaths between birth to 44 years of age are largely due to one of six infectious diseases and when in the span of 30 years AIDS has become the second most important infectious killer in the world—the costs of treating infectious diseases are also rising.
 At the same time, infectious diseases are taxing economies. The 1991 cholera epidemic in Peru cost that country an estimated $770 million. The plague epidemic in India cost that country $1.8 billion. Between 1990 and 1998, BSE in the United Kingdom is thought to have cost more than $6 billion. Although while these diseases may not be high on the list of causes of mortality, they are high on the list of causes of economic morbidity.
 Emerging infections are a critical phenomenon. The globalization occurring in the world community provides a reminder of this fact. Efforts to combat emerging infections require a global response to provide adequate financial support. Public commitment needs to be developed, for where there is public commitment it will be followed by political resolve, and where there is both political and public determination there are windows of opportunity to eradicate and eliminate infectious diseases.
 WHO estimates that infectious diseases account for more than 17 million deaths per year worldwide and that at least 30 new infectious diseases have emerged within the last two decades. The world's more than 7 billion people are at risk for many endemic diseases, with the most populated and economically weak countries in Southeast Asia at highest risk. 
New microorganisms capable of causing disease in human continue to be detected. Whether an emerging microorganism develops into a public health threat depends on factors related to the microorganisms and its environment, or the infected human and his/her environment. Such factors include ease of transmission between animals and people and among people, potential for spread beyond the immediate outbreak site, severity of illness, availability of effective tools to prevent and control the outbreak, and ability to treat the disease. Some of the new agents detected in the past 30 years are now genuine public health problems on a local, regional or global scale.

Antimicrobial Resistance
Antimicrobial resistance (AMR) is resistance of a microorganism to an antimicrobial medicine to which it was previously sensitive. Resistant organisms are able to withstand attack by antimicrobial medicines, such as antibiotics, antivirals, and antimalarials, so that standard treatments become ineffective and infections persist and may spread to others. AMR is a consequence of the use, particularly the misuse, of antimicrobial medicines and develops when a microorganism mutates or acquires a resistance gene. Infections caused by resistant microorganisms often fail to respond to the standard treatment, resulting in prolonged illness and greater risk of death. AMR reduces the effectiveness of treatment because patients remain infectious for longer, thus potentially spreading resistant microorganisms to others.
In many regions, the low cost, first choice antibiotics have lost their power to clear infections of Eschercichia coli, Neisseria gonohorrea, Pneumococcus, Shigella, Staphylococcus aureus – increasing the cost and length of treatment of many common diseases including epidemic diarrhoeal diseases, gonorrhea, pneumonia, and otitis. Further problems stem from the use of antimicrobial substances in food animal production.
In an age of expanding air travel and international trade, infectious microbes are transported across borders every day, carried by infected people, animals, and insects, and contained within commercial shipments of contaminated food. Moreover, unforeseen disease problems continue to appear. Left unchecked, today’s emerging diseases can become the endemic diseases of tomorrow. This is what happened with HIV/AIDS, which spread from a remote part of Africa to all other continents 30 years ago, and is now entrenched all over the world, necessitating a major international control efforts.
Infectious diseases do not recognize borders. Infectious diseases like malaria and AIDS act as a massive societal brake, slowing both economic and human development. Each year, malaria slows economic growth in several sub-Saharan African countries by as much as 1.3 percent per person per year.
 Infections caused by resistant microorganisms often fail to respond to conventional treatment, resulting in prolonged illness and greater risk of death. About 440 000 new cases of multidrug-resistant tuberculosis (MDR-TB) emerge annually, causing at least 150 000 deaths.
A high percentage of hospital-acquired infections are caused by highly resistant bacteria such as methicillin-resistant Staphylococcus aureus (MRSA). Inappropriate and irrational use of antimicrobial medicines provides favourable conditions for resistant microorganisms to emerge, spread and persist.
Many infectious diseases risk becoming uncontrollable and could derail the progress made towards reaching the targets of the health-related United Nations Millennium Development Goals set for 2015.
When infections become resistant to first-line medicines, more expensive therapies must be used. The longer duration of illness and treatment, often in hospitals, increases health-care costs and the financial burden to families and societies.
The achievements of modern medicine are put at risk by AMR. Without effective antimicrobials for care and prevention of infections, the success of treatments such as organ transplantation, cancer chemotherapy and major surgery would be compromised.
Resistance is an emerging concern for treatment of HIV infection, following the rapid expansion in access to antiretroviral medicines in recent years; national surveys are underway to detect and monitor resistance.
Ciprofloxacin is the only antibiotic currently recommended by WHO for the management of bloody diarrhoea due to Shigella organisms, now that widespread resistance has developed to other previously effective antibiotics. But rapidly increasing prevalence of resistance to ciprofloxacin is reducing the options for safe and efficacious treatment of shigellosis, particularly for children. New antibiotics suitable for oral use are badly needed.
AMR has become a serious problem for treatment of gonorrhoea, involving even "last-line" oral cephalosporins, and is increasing in prevalence worldwide. Untreatable gonococcal infections would result in increased rates of illness and death, thus reversing the gains made in the control of this sexually transmitted infection.
New resistance mechanisms, such as the beta-lactamase NDM-1, have emerged among several gram-negative bacilli. This can render powerful antibiotics, which are often the last defence against multi-resistant strains of bacteria, ineffective.
Inappropriate and irrational use of medicines provides favourable conditions for resistant microorganisms to emerge and spread. For example, when patients do not take the full course of a prescribed antimicrobial or when poor quality antimicrobials are used, resistant microorganisms can emerge and spread.
Underlying factors that drive AMR include: inadequate national commitment to a comprehensive and coordinated response, ill-defined accountability and insufficient engagement of communities; weak or absent surveillance and monitoring systems; inadequate systems to ensure quality and uninterrupted supply of medicines, inappropriate and irrational use of medicines, including in animal husbandry: poor infection prevention and control practices;  depleted arsenals of diagnostics, medicines and vaccines as well as insufficient research and development on new products.
The emergence of AMR is a complex problem driven by many interconnected factors; single, isolated interventions have little impact. A global and national multi-sectoral response is urgently needed to combat the growing threat of AMR. Antimicrobial resistance occurs everywhere but is particularly a concern in countries where prescription of antimicrobials is unregulated and where you can buy antibiotics over the counter.
We are now on the brink of losing this precious arsenal of medicines. The use and misuse of antimicrobials in human medicine and animal husbandry over the past 70 years have increased the number and types of micro organisms resistant to these medicines, causing deaths, greater suffering and disability, and higher health-care costs.
If this phenomenon continues unchecked, many infectious diseases risk becoming uncontrollable and could derail progress made towards reaching the health related United Nations Millennium Development Goals for 2015. Furthermore, the growth of global trade and travel allows resistant organisms to spread worldwide within hours. The emergence of AMR is a complex problem driven by many interconnected factors. It is imperative on all key stakeholders, including policy-makers and planners, the public and patients, practitioners and prescribers, pharmacists and dispensers, and the pharmaceutical industry, to act and take responsibility for combating antimicrobial resistance.

Prof. Syed Amin Tabish (FRCP, FAMS, FRCPE, FACP, MHA (AIIMS) is Chiarman Accident & Emergency Department, Head, Hospital administration & Medical Superintendent, Sher-i-Kashmir Institute of Medical sciences, Srinagar.

Lastupdate on : Wed, 6 Apr 2011 21:30:00 Makkah time
Lastupdate on : Wed, 6 Apr 2011 18:30:00 GMT
Lastupdate on : Thu, 7 Apr 2011 00:00:00 IST