Hospital acquired infections (HAIs) are a major issue affecting those in hospital care and can lead to increased morbidity and mortality. It has been shown that approximately 80% of all HAIs are caused by bacteria and are predominately spread via contaminated instruments, surfaces and person-to-person contact. While HAIs are a potential risk to all patients, those most at risk are patients in the intensive care unit, burn victims, organ receivers and neonates. In addition to contributing to increased mortality and morbidity rates, recent studies have shown that HAIs caused by the bacteria Clostridiodes difficile contribute $1 billion in excess medical costs per year and approximately 14,000 deaths.
Current detection systems in the hospital environment are time expensive and can lead to false negatives due to the ever-evolving nature of bacteria. Highlighting the need for a rapid detection system that can detect the presence of common HAI causing bacteria on surfaces and instruments to enable appropriate disinfection and ultimately prevent their spread.
A promising new form of detection system is the use of short single-stranded oligonucleotides folded into a three-dimensional shape, known as aptamers. Aptamers a generated through a process known as SELEX, which involves the selection of ligands that bind to the desired target molecules. By generating aptamers specific to unique, conserved proteins expressed on the surface of common HAI causing bacteria a rapid point-of-care detection system may be developed. Here we show that two of the more common HAI causing bacteria, Staphylococcus aureus and C. difficile; each have a unique surface expressed protein that is conserved throughout most strains of these species. Protein A is expressed by S. aureus and is used to evade the host immune system and N-acetyl-muramoyl-L-alanine amidase is expressed by C. difficile and is used in the replication process. Aptamers targeting these and other similar proteins could be utilised for immediate detection of these bacterial species, with subsequent action to sterilise and decontaminate surfaces and instruments, thus potentially reducing the impact of HAIs.