Zero tolerance for healthcare-associated MRSA bacteraemia: is it realistic?

Simon R. Harris,Michael E. D. Allison,M. Estée Török,Nicholas M. Brown,Direk Limmathurotsakul,Kathy E. Raven,Edward J. P. Cartwright,Sharon J. Peacock,Michael A. Quail,Julian Parkhill,Matthew T. G. Holden,Daniel Greaves

doi:10.1093/jac/dku128

Abstract

BackgroundThe term ‘zero tolerance’ has recently been applied to healthcare-associated infections, implying that such events are always preventable. This may not be the case for healthcare-associated infections such as methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia.MethodsWe combined information from an epidemiological investigation and bacterial whole-genome sequencing to evaluate a cluster of five MRSA bacteraemia episodes in four patients in a specialist hepatology unit.ResultsThe five MRSA bacteraemia isolates were highly related by multilocus sequence type (ST) (four isolates were ST22 and one isolate was a single-locus variant, ST2046). Whole-genome sequencing demonstrated unequivocally that the bacteraemia cases were unrelated. Placing the MRSA bacteraemia isolates within a local and global phylogenetic tree of MRSA ST22 genomes demonstrated that the five bacteraemia isolates were highly diverse. This was consistent with the acquisition and importation of MRSA from the wider referral network. Analysis of MRSA carriage and disease in patients within the hepatology service demonstrated a higher risk of both initial MRSA acquisition compared with the nephrology service and a higher risk of progression from MRSA carriage to bacteraemia, compared with patients in nephrology or geriatric services. A root cause analysis failed to reveal any mechanism by which three of five MRSA bacteraemia episodes could have been prevented.ConclusionsThis study illustrates the complex nature of MRSA carriage and bacteraemia in patients in a specialized hepatology unit. Despite numerous ongoing interventions to prevent MRSA bacteraemia in healthcare settings, these are unlikely to result in a zero incidence in referral centres that treat highly complex patients.

Highlights

Evidence that this can be achieved includes an 87% reduction in methicillinresistant Staphylococcus aureus (MRSA) bacteraemias reported to Public Health England from 7291 in 2001/02 to 924 in 2012/13.3 This followed the introduction of mandatory surveillance for S. aureus bacteraemia, together with the implementation of a package of infection control measures including hand hygiene, MRSA screening and decolonization, patient isolation and infection prevention care bundles
Clinical and bacterial genomic investigation of four patients with MRSA bacteraemia Five MRSA bacteraemias occurred in four patients admitted to the hepatology ward at Cambridge University Hospitals NHS Foundation Trust (CUH) between September 2011 and August 2012
The antibiotic susceptibility profiles for the MRSA bacteraemia isolates from three patients (P1, P2 and P4) were identical and showed two antibiotic susceptibility differences from the isolate from P3, which was resistant to erythromycin, with inducible resistance to clindamycin

Summary

Introduction

Reducing healthcare-associated infections caused by methicillinresistant Staphylococcus aureus (MRSA) represents an important healthcare priority.[1,2] Evidence that this can be achieved includes an 87% reduction in MRSA bacteraemias reported to Public Health England from 7291 in 2001/02 to 924 in 2012/13.3 This followed the introduction of mandatory surveillance for S. aureus bacteraemia, together with the implementation of a package of infection control measures including hand hygiene, MRSA screening and decolonization, patient isolation and infection prevention care bundles.1,2,4 – 8 England has entered a new phase of control in which the term ‘zero tolerance’ has been used with reference to healthcare-associated infections, including MRSA bacteraemia.8,9‘Zero tolerance’ was first used to describe policing techniques in New York City in situations relating to criminal acts, often resulting in punishment for minor infringements and not taking into# The Author 2014. England has entered a new phase of control in which the term ‘zero tolerance’ has been used with reference to healthcare-associated infections, including MRSA bacteraemia.. The term ‘zero tolerance’ has recently been applied to healthcare-associated infections, implying that such events are always preventable. This may not be the case for healthcare-associated infections such as methicillin-resistant Staphylococcus aureus (MRSA) bacteraemia

Methods

Results

Conclusion