Multi-antibiotic resistant Enterobacteriaceae and near-patient environmental decontamination: are current methods adequate in the face of changing epidemiology and enhanced transmission
Dr D Fitzgerald-Hughes
Monday, December 02, 2019
Competition Funded PhD Project (Students Worldwide)
Patients with infections caused by antibiotic-resistant bacteria are at increased risk of worse clinical outcomes and death. Klebsiella pneumoniae – a common intestinal bacteria that can cause life-threatening infections, is increasingly resistant to a last resort antibiotic, carbapenem, making it a multidrug resistant (MDR) pathogen and an almost untreatable ‘superbug’. Carbapenemaseproducing (CP) Enterobacteriaceae (CPE) which include mainly K. pneumoniae and Escherichia coli have spread to all regions of the world. CPE are a major cause of hospital-acquired infections such as pneumonia, bloodstream infections, and infections in newborns and intensive-care unit patients. In some countries, because of resistance, carbapenem antibiotics do not work in more than half of people treated for K. pneumoniae infections and hence morbidity rates as high as 50% are reported.
Infections rates involving CPE are rising and outbreaks are increasingly reported globally. To protect patients and prevent transmission in the USA, agencies such as the Centre for Disease Control and Prevention (CDC), Health Protection England and the Irish Health Protection Surveillance Centres provide recommendations for prevention and control of CPE that include contact precautions, patient/staff cohorting, hand-washing, surveillance and antibiotic stewardship. However, guidelines lack emphasis on the environments role in the transmission of CPE. Aggressive decontamination of the environment close to patients colonised with CPE has been pursued in some hospitals but mainly in response to the identification of environmental reservoirs and the finding of ineffective disinfection. Appropriate and effective decontamination of the healthcare environment in relation to CPE requires a more evidence-based understanding of the epidemiology and transmission of CPE in healthcare settings, a goal that this proposal will address.
We showed that CP Klebsiella survive longer than other CPE on surfaces commonly found in patient bedspaces and are more resistant to disinfectants at twice the recommended concentrations. In this project, we will further investigate the survival of antibiotic-resistant and -susceptible K. pneumoniae and E. coli on surfaces, correlated with the adherence traits of these organisms and bacterial fitness. Bacterial survival on surfaces, decontaminated using current disinfection guidelines, will be investigated under laboratory conditions and the development of disinfectant tolerance will be investigated. In a hospital-based study, we will determine the burden of K. pneumoniae and E. coli in the environment of colonised/infected patients. We will determine the effectiveness of routine surface cleaning in relation to target organisms and simultaneously we will evaluate the cleaning standard achieved on surfaces, based on removal of a fluorescent dye applied to multiple surfaces. The relatedness of environmental isolates and isolates recovered from patients will be investigated by whole genome sequencing to identify routes and reservoirs of transmission. These studies will provide evidence of potential clinical sources of patient acquisition and will determine the relationship between cleaning thoroughness and cleaning effectiveness for recovery of these pathogens. As such, it will inform future infection prevention and control policy with regard to CPE.