MThe term ‘antimicrobial agent’ refers to specific synthetic or natural substances such as drugs, chemicals, or extracts that have the ability to either kill or inhibit the growth of microbes, including bacteria, fungi and algae [1]. Antibiotics have played a tremendous role in attenuating mortality and morbidity of humans since the antibiotic era started at the early of the last century [2,3]. The introduction of antibiotics into therapeutics has extended the average human life expectancy by around 23 years in just 100 years [4]. However, because of widespread misuse of antibiotics, bacteria have developed mechanisms to escape from antimicrobial agents. Although antibiotic resistance is a natural phenomenon [5] (it was observed before the extensive use of penicillin [6]), its pace has been accelerated due to overuse, inappropriate prescribing and extensive agricultural use [7]. Today, antimicrobial resistance is one of the greatest challenges for global health, and the World Health Organization (WHO) has declared it one of the top threats for humanity [8]. In the United States, more than 2.8 million people are infected by antibiotic-resistant bacteria, with over 35,000 deaths every year. An estimated USD $4.6 billion is spent to fight only six multidrug-resistant pathogens [9]. Globally, drug resistant infections cause half a million deaths each year, and the toll is suspected to exceed 10 million by 2050 [10]. Many first-line antibiotics are predicted to be ineffective by 2025 and, consequently, the ‘post antibiotic era’ will start soon, or may already has started [9,11]. Though the discovery of new antibiotics is critical, concerning the pace of antibiotic resistance, unfortunately, a huge innovation gap has been created in antibiotic drug discovery after the end of its ‘golden era’ between 1950 and 1970 [12]. It is almost 50 years since the last new antibiotic was discovered, and research funding to find new antibiotics has been drastically reduced in both the pharmaceutical and academia domain, which considering such investment nonprofitable during an economic crisis [13,14]. In 2017, the WHO published a global priority pathogen list comprising 12 species of bacteria categorized by critical, high, and medium antibiotic resistance, with the aim of ensuring quick R&D responses, guiding strategic directions and achieving new antibiotics for urgent public health needs (Figure 1) [15]. The United States Centers for Disease Control and Prevention’s (CDC) 2019 AR Threats Report listed 18 germs, including bacteria and fungi, on three levels of human health concern: urgent, serious, and concerning, as a measure of estimation of antibiotic resistance burden in the USA [9]. Today, the world is witnessing how an emerging infectious disease such as the COVID-19 pandemic, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), can result from a lack of appropriate medicines, in addition to many other causes. The pandemic led to more than 4.8 million documented deaths globally in the 23 months up to 6 October 2021 [16].
29/12/2021