Infection prevention strategies reviewed

As the 7th international conference of the Hospital Infection Society approaches, it is worth taking a moment to reflect on the progress achieved in the field of infection prevention and control, in recent years. Where are we now and where do efforts need to be concentrated in the future? Infection control teams have a great deal to celebrate, as sustained efforts have resulted in major reductions in MRSA and C. difficile infections in recent years. Driven by stringent targets, introduced by the previous Government, annual figures showed a 35% reduction in MRSA cases and a 29% reduction in C. difficile cases, compared to the previous year.1 Announcing the results, Dr Christine McCartney, from the HPA, commented that this was a “credit to the hard work of colleagues in the NHS which continues to strengthen good practice in infection control measures.” However, there can be no room for complacency. In particular, extra efforts will be required to address the variability in performance across UK Trusts. A report by the National Audit Office (NAO), entitled Reducing Healthcare Associated Infections in Hospitals in England,2 observed that improvements have not been evident across all Trusts and significant scope remains for hospitals to improve infection control further. According to the report, the biggest threat remains antibiotic resistance – with poor data on hospital prescribing limiting the ability to evaluate the effectiveness of usage, while other barriers to further improvement include bed occupancy and the availability of isolation facilities. Earlier this year, the healthcare regulator, Monitor, also revealed concerns that the economic downturn will affect hospital performance on MRSA and C. difficile. Despite the immense challenges posed by the financial pressures ahead, the Department of Health responded with a statement that “Trusts will be expected to continue to reduce rates of HCAIs”. Furthermore, the NHS should “aim for a zero tolerance approach to all healthcare-associated infections”.3 The new Government has already introduced some changes in the infection control arena. Patients will now have access to more data on their local hospital’s infection control performance in the wake of a decision to publish weekly hospital data on MRSA bloodstream infections and C. difficile. Previously, data was only published monthly, by NHS Trusts, but infection figures for every NHS hospital in England will now be updated on data.gov.uk, on a weekly basis, giving statistics for each of the previous 12 weeks. According to Health Secretary, Andrew Lansley, this will enable patients to make meaningful choices based on comparisons between different hospitals and healthcare organisations. The Department of Health is also exploring the possibility of taking this further – for example, by providing data on other infections and by looking at whether information could be published at department or ward level. Previously, the NAO concluded that there has been insufficient focus on other HCAIs and highlighted the fact that rates of Escherichia coli and klebsiella blood stream infection are now on the increase. It is hoped that, if the Government expands surveillance, the monitoring of other infections may go some way to address this imbalance. Although plans to report on other infections are yet to unfold, it would appear that the NHS will be coming under greater scrutiny in the not too distant future.

New threats

Unfortunately, just as progress is achieved with one group of antibiotic-resistant superbugs, another threat appears on the horizon – the headlines have been dominated in recent weeks with news of an enzyme that can make bacteria resistant to even the most powerful antibiotics. Although around only 50 cases of the NDM-1-infected bacteria have been identified in the UK so far, scientists and doctors fear the superresistant strains could spread quickly. Professor Tim Walsh, from the Cardiff School of Medicine’s Department of Medical Microbiology, first identified the NDM-1 gene in Klebsiella pneumoniae and E. coli bacteria taken from a Swedish patient admitted to hospital in India in 2009.4 The new NDM-1-producing bacteria are resistant to many antibiotics including carbapenems, a group of antibiotics generally reserved for use in emergencies and the treatment of infections caused by multi-resistant bacteria. Prof. Walsh investigated how common the NDM-1 producing antibiotic resistant bacteria are in Bangladesh, India, and Pakistan and the importation of these bacteria into the UK via patients returning from these countries. He commented: “A new gene NDM-1 that enables bacteria to be highly resistant to almost all antibiotics is widespread in Enterobacteriaceae taken from patients in India and Pakistan, and has also been found in UK patients who travelled to India for elective surgery.” The study collected bacteria samples from patients presenting with various hospital and community-associated infections in Chennai and Haryana in India, and from patients referred to the UK’s national reference laboratory between 2007 and 2009. Samples were tested for antibiotic susceptibility and the presence of the NDM-1 gene using polymerase chain reaction (PCR) and sequencing. They identified 44 (1.5%) NDM-1 positive bacteria in Chennai, 26 (8%) in Haryana, 37 in the UK, and 73 in other sites in Bangladesh, India, and Pakistan. NDM-1 was mostly found in E. coli (36), the most common cause of communityassociated urinary tract infections, and K. pneumoniae (111). The NDM-1-producing bacteria were highly resistant to all antibiotics except tigecycline and colistin. In some cases, isolates were resistant to all antibiotics. The emergence of NDM-1 positive bacteria is potentially a serious global public health problem as there are few new anti-Gram-negative antibiotics in development and none that are effective against NDM-1. Prof. Walsh commented: “The rapid emergence of these multi-drug resistant NDM-1 producing bacteria and their potential worldwide spread could herald a period in which antibiotics become redundant and demands very close international monitoring and surveillance.”