Antimicrobial resistance: Global public health nightmare

SINCE their discovery, antibiotics have served as the cornerstone of modern medicine; fight against life threatening infectious diseases such as pneumonia, battle against conditions such as cancer, where antibiotics are crucial in helping chemotherapy patients avoid and fight opportunistic infection, enhancing huge advances in surgical procedures like organ transplants and caesarean sections, which have now become routine and relatively low risk, thanks to our ability to effectively stave off or treat acute infections with antibiotics. However, the persistent overuse and misuse of antibiotics in human and animal health have encouraged the emergence and spread of antibiotic resistance, which occurs when microbes, such as bacteria, become resistant to the drugs used to treat them.

Antimicrobial resistance (AMR) has become one of the biggest threats to global health and endangers other major priorities, such as human development. All around the world, many common infections are becoming resistant to the antimicrobial medicines resulting in longer illnesses and more deaths. At the same time, not enough new antimicrobial drugs, especially antibiotics, are being developed to replace older and increasingly ineffective ones. Common and life-threatening infections like pneumonia, gonorrhoea, and post-operative infections, as well as HIV, tuberculosis, and malaria are increasingly becoming untreatable because of AMR. Left unchecked, AMR is predicted to have significant social, health security, and economic repercussions that will seriously undermine the development of countries.

In 25 May 2015, The World Health Assembly delegates agreed resolutions to tackle antimicrobial resistance; improve access to affordable vaccines and address over- and under-nutrition at Geneva. A global action plan to tackle antimicrobial resistance was endorsed – including antibiotic resistance, the most urgent drug resistance trend. The maiden edition of World Antimicrobial Awareness Week (WAAW) was launched 16-22 November 2015, and ever since, each November is WAAW. WAAW aims to increase global awareness of antibiotic resistance and to encourage best practices among the general public, health workers and policy makers to avoid the further emergence and spread of antibiotic resistance. Similarly, Global leaders met at the United Nations General Assembly in New York in September 2016 to commit to fighting antimicrobial resistance together. This was only the fourth time in the history of the UN that a health topic is discussed at the General Assembly (HIV, noncommunicable diseases, and Ebola were the others). Heads of State and Heads of Delegations addressed the seriousness and scope of the situation and agreed on sustainable, multi-sectoral approaches to addressing antimicrobial resistance.

The high levels of AMR already seen in the world today are the result of overuse and misuse of antibiotics and other antimicrobials not just in our hospitalsor in humans, but animals (including farmed fish), and crops, as well as the spread of residues of these medicines in soil, crops, and water, which one way or the other serve as training ground for adaptation to subinhibitory concentration of the antibiotic(s) in question.. Within the broader context of AMR, resistance to antibiotics is considered the greatest and most urgent global risk requiring international and national attention.Agriculture must shoulder its share of responsibility, both by using antimicrobials more responsibly and by cutting down on the need to use them, through good farm hygiene.

Nigeria and other sub-Saharan African countries face an increasing number of healthcare associated infections caused by multi-drug resistant (MDR) Gram-negative bacteriaand Gram positive cocci;methicillin resistant Staphylococcus aureus(MRSA); vancomycin resistant Staphylococcus aureus(VRSA). Pathogenic species have evolved resistance to multiple antimicrobial agents including the mainstays of treatment. This is of concern as there are few new antibiotics in development with activity against bacteria. Carbapenems have become a mainstay of therapy for the treatment of multidrug resistant Gram-negative bacteria. This has led to an increase in carbapenem use for treatment of serious infections. As a result, there has been a selective pressure for carbapenem resistance and carbapenem resistant strains have spread globally. Worryingly, carbapenem-resistant bacteria are often resistant to other classes of antibiotics including aminoglycosides, fluoroquinolones and other ß-lactams, with often colistin and tigecycline as the only effective drugs. Resistance to both these antibiotics can also easily evolve making them unreliable as ‘last resort’ therapies.

Perhaps most worryingly, this does not appear to be a problem restricted to hospital patients with resistance rates in commensal isolates being carried commensally equally highfrom humans and animals in Nigeria and in isolates from products of the food chain and sewage, demonstrating a variety of sources and reservoirs for these resistance determinants. These resistant bacteria can enter the human food chain through the consumption of meat or by direct contact, colonizing the human gut. This underpins the urgent requirements for enhanced surveillance of drug-resistance in sub-Saharan Africa and the need for interventions to minimise the selection and transmission of antibiotic resistant bacteria. In conclusion, the uncontrolled use of antibiotics in Nigeria is likely to have contributed largely to this situation. Research needs to continue to ensure there is not a return to the conditions of a pre-antibiotic era as multi-drug resistant bacteria become dominant. Given the ease and frequency with which people now travel, antibiotic resistance is a global problem, requiring efforts from all nations and many sectors using one health (health, agriculture and environment) approach for intervention. The loss of antimicrobial action would make modern medicine impossible, it would not only affect infection; simple wounds, UTIs, pneumonia, meningitis, septicaemia but all branches of medicine including trauma, surgery, childbirth, cancer treatments and transplants would become hazardous.

• Ogbolu, PhD, is Reader, Infectious Diseases & Antimicrobials at Ladoke Akintola University of Technology, Ogbomoso, Oyo State.