What is antimicrobial Resistance (AMR)
What is Antimicrobial Resistance, it's causes and impact
One of the biggest challenges infront of us as a society, a silent killer is the occurrence of Antimicrobial Resistance (AMR).
AMR is the emergence of resistance in disease causing bacterial strains towards most if not all antibiotics that are traditionally used to treat them, rendering large swathes of human population unprotected especially in areas where these infections and infectious agents are highly prevalent and known to cause infections.
Some of the recorded occurrences of antimicrobial resistance in bacterial strains include:
Methicillin-resistant Staphylococcus aureus (MRSA): These strains are resistant to methicillin and other beta-lactam antibiotics.
Vancomycin-resistant Enterococcus (VRE): Vancomycin is a last-resort antibiotic for treating gram-positive bacterial infections. These strains are resistant to this antibiotic.
Extended-spectrum beta-lactamase (ESBL)-producing Enterobacteriaceae: Resistant to many beta-lactam antibiotics, including penicillins and cephalosporins.
Carbapenem-resistant Enterobacteriaceae (CRE): Resistant to carbapenems, a class of antibiotics used for severe or high-risk bacterial infections.
Multidrug-resistant Pseudomonas aeruginosa: Resistant to multiple classes of antibiotics, making infections difficult to treat.
Multidrug-resistant Acinetobacter baumannii: Resistant to several antibiotics, often causing healthcare-associated infections with limited treatment options.
The emergence of resistance is usually manifested as changes in the genome or epigenetic changes where drug targets for existing antibiotics are no longer addressable or the organism develops additional mechanisms that remove or block the effects of the drug.
A key contributor to the emergence of these resistant strains are
Overuse and incorrect usage of antibiotics for treating infections in humans
Indiscriminate usage of antibiotics in farming and animal husbandry
No new antibiotics - the innovation funnel in this space has dried out
Inadequate infection prevention programs and
Increase in global travel and spread of infections through highly mobile individuals
This variety in the causes of AMR highlights that tackling this is a multi-pronged challenge and therefore requires cross sectoral systems thinking for us as a society to come together and tackle AMR. Efforts like the One Health initiative are aimed at achieving optimal health outcomes by understanding the interconnected nature and relationships between human, animal and environmental health by acting at the global, national and regional levels through multi-sectorial levels of activities.
Source: CDC
The impact of AMR is that previously curable infections are getting less and less addressable through existing drugs and infections which previously had been of minor consequence are now manifesting into serious health hazards with limited to no recourse to effective treatment options.
This means that very soon we might find ourselves in a scenario where none of the existing antibiotics are able to offer protection against some pathogens and result in deaths to the tune of 1·27 million (95% uncertainty interval 0·911–1·71) in 2019, directly attributable to AMR (read paper by Murray and colleagues here). This number is equal to the number of malaria and AIDS related deaths out together.
Due to the emergence or resistance, some of the pathogens that require urgent innovation that develops new antibiotics as per the priority list of WHO include
Source: REPAIR Impact Fund, WHO pathogen list (2017)
A number of these pathogens, especially those with the “critical” status are hospital related infections and infections that occur in immune compromised patients like those being treated by chemotherapy. These are commonly occuring infections, and can often be unavoidable. Considering this, it is scary the drug discovery efforts to target these pathogens haven't either been actioned or have not yet produced meaningful results.
Recent announcements from companies like Bug Works with a first-in class, novel bacterial topoisomerase inhibitor (GYROX) shows promise. With phase 3 trials expected to start in 2024, more news on it's rollout to patients in the future is expected.
In the next set of posts, I will explore each of the issues contributing to the emergence of AMR, stakeholders who will need to play important roles in tackling these issues and discuss potential solutions being used to address the different causes of AMR.
By doing this, I hope to have provided you an insight and a framework that you can use to understand AMR, know about areas where solutions exist and where lot more needs to be done and finally think about how you can make a positive impact to this global effort to address the emergence of AMR.
I hope you have a great week ahead