Antimicrobial resistance is an increasingly serious threat to global public health that shows no signs of abating. In fact new modes of resistance are constantly evolving amongst the microorganisms (such as bacteria, fungi, viruses, and parasites) when they are exposed to antimicrobial drugs (such as antibiotics, antifungals, antivirals, antimalarials, and anthelmintics).

This leads to increased incidences of rapidly spreading strains of highly pathogenic microorganisms (such as the now familiar MRSA - methicillin-resistant Staphylococcus aureus) threatening our ability to treat common infectious diseases, resulting in prolonged illness, disability, and death. For example people with MRSA are estimated to be 64% more likely to die than people with a non-resistant form of the infection.

As such, identifying and understanding the sources and pathways for antimicrobial-resistant bacteria (ARB) is critical.

A recent study led by UCC School of BEES researchers Dr Jean O’Dwyer, Dr John Weatherhill and Luisa Andrade (with collaborators in Dublin and Canada) has revealed that almost a third of the studied groundwater sources harboured resistant bacteria.

This study is the first systematic review and pooled analysis of antimicrobial resistant bacteria occurrence in global groundwater supplies, which are used as primary drinking water sources by 2.2 billion people worldwide and are recurrently linked to significant outbreaks of infection

Findings from the study showed that:

• 4% ± 32.6 of studied sources harboured resistant bacteria.
• In total, 80.2% ± 29.0 of aggregated isolates were antimicrobial-resistant.
• Overall, 57% ± 36.8 of isolates were resistant to ≥3 antimicrobials.

These results leave little doubt that groundwater represents a major global reservoir for antimicrobial resistance, however significant research is required to establish environmental determinants and mechanisms mediating their occurrence

Full paper can be read here