Bacteria (“bugs”) are becoming increasingly resistant to antibiotic drugs, and some bacteria are now resistant to some of our last-resort antibiotics, a class of drug known as carbapenems. Carbapenem resistance is encoded by several genes, or packages of genetic material, which can be passed from one bacterial bug to another. The bacteria do this by sharing pieces of DNA (genetic material) known as plasmids, which contain these carbapenem resistance genes. Common carbapenem resistance genes include NDM-1.
An outbreak of infections caused by a type of bug known as Serratia, which is known to cause disease in small babies and hospitalised patients, was identified across two hospitals in Romania. The Serratia causing infection in these patients were resistant to carbapenems and several other class of antibiotic. We used a new type of whole genome sequencing (known as long-read sequencing) to fully decipher the genetic code of these Serratia, in combination with the more commonly-used short read sequencing. Using this information, we could work out that the same plasmid was responsible for the spread of the NDM-1 gene across multiple species, or types, of bacterial bug, and several different types of Serratia. This NDM-1 plasmid has been seen in other countries, and has spread globally.
· Understanding how resistance genes spread is crucial to developing effective interventions to limit how quickly this occurs
· Whole genome sequencing is currently the most accurate method in understanding how resistance genes spread
· Resistance gene spread in bacteria is an international phenomenon, and efforts to target it must take into account this global dimension
The full article is available here:
Illumina short-read and MinION long-read WGS to characterize the molecular epidemiology of an NDM-1 Serratia marcescens outbreak in Romania
H T T Phan, N Stoesser, I E Maciuca, F Toma, E Szekely, M Flonta, A T M Hubbard, L Pankhurst, T Do, T E A Peto, A S Walker, D W Crook, D Timofte
This work was supported by the Health Innovation Challenge Fund [a parallel funding partnership between the Wellcome Trust (WT098615/Z/12/Z) and the Department of Health (grant HICF-T5-358)]; the National Institute for Health Research (NIHR) Oxford Biomedical Research Center (BRC) Program; and the Health Protection Research Unit (NIHR HPRU) in Healthcare Associated Infections and Antimicrobial Resistance at the University of Oxford, in partnership with Public Health England (PHE); and the Microbiology Society (International Development Fund, IDF14/01).