Year: 2015

Molecular diagnostics for C. difficile infection: too much of a good thing?

Jon Otter (@jonotter) C. difficile , , , ,

A study in JAMA Internal Medicine suggests that we may be ‘overdiagnosising’ C. difficile in this era of molecular diagnostics. The researchers from California grouped the 1416 patients tested for C. difficile into three groups: Tox+/PCR+ (9%), Tox-/PCR+ (11%), and Tox-/PCR+ (79%) (see Figure). Perhaps unsurprisingly, compared with Tox+/PCR+ cases, Tox-/PCR+ cases had lower bacterial load, less prior antibiotic exposure, less faecal inflammation, a shorter duration of diarrhoea, were less likely to suffer complications, and were less likely to die within 30 days. Perhaps even more importantly, patients with Tox-/PCR+ were pretty much identical to patients with Tox-/PCR- specimens in all of these metrics. In short: these patients had C. difficile in their gut, but they did not have C. difficile infection. The key message here is that we should not be treating patients who are C. difficile “positive” by molecular tests only.

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Reflections from Infection Prevention 2015 Part III: Thinking outside the box

Jon Otter (@jonotter) Conferences , , , , , , ,

think outside the box

For the third and final installment of my blog-report from Infection Prevention 2015, I thought I’d cover some of the more innovative approaches in and around the IPC sphere:

Part I: Beating the bugs

Part II: Improving the systems

Part III: Thinking outside the box

New technology to improve hand and environmental hygiene

I for one am pretty sick of seeing unrealistically high levels of hand hygiene compliance being reported from peer-to-peer manual auditing approaches. One way to get more realistic compliance data is through automated approaches to hand hygiene compliance, reviewed here by Drs Dawson (Warwick) and Mackrill (Imperial College London), who also presented their findings at the conference, and by another group here. Drs Dawson and Mackrill considered issues around product usage, self-reporting, direct observation, perceptions of technology (often viewed, unhelpfully, as a ‘silver bullet’), and staff perceptions of need and benefit. They divided the technology into those that monitored product usage, surveillance systems that monitored individual performance, and systems that monitored both product usage and individual performance. Although automated surveillance systems will always be imperfect and involve a degree of inference, would you rather monitor the 5 moments sporadically / badly or have robust measurements of a smaller number of moments? Automated surveillance methods will not replace manual audits – at least for now – but it’s time to take a long hard look at what is available.

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Reflections from Infection Prevention 2015 Part II: Improving the systems

Jon Otter (@jonotter) Conferences , , , , ,

Swiss_cheese_model_of_accident_causation

Welcome to the second installment of my blog-report from Infection Prevention 2015, focused on improving the systems around the delivery of safe healthcare, and infection prevention and control:

Part I: Beating the bugs

Part II: Improving the systems

Part III: Thinking outside the box

The economics of HCAI is going to become increasingly important as the NHS – and healthcare systems worldwide – continue to “seek efficiency savings” (aka demand more for less). So the overview of HCAI economics from Dr Nick Graves (QUT, Australia) was timely. I find it remarkable that we are still so reliant on the 2000 Plowman report to gauge the cost of HCAI – surely there must be a more sophisticated approach? There is something rather uncomfortable about setting an ‘acceptable’ level of HCAI, or putting a £ value that we would be prepared pay to save a life, but this is exactly what we have to do to manage the demands of scarcity. Dr Graves presented some useful worked examples to illustrate his point, around coated catheters, hip replacements, hand hygiene improvement, and MRSA screening. In most cases, there comes a point where a health benefit is too expensive to ‘purchase’, which is an uncomfortable but very real choice across all areas of healthcare (e.g. cancer drugs).

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Reflections from Infection Prevention 2015 Part I: Beating the bugs

Jon Otter (@jonotter) Conferences , , , ,

time person of the year

Infection Prevention 2015, the annual conference of IPS, was held in Liverpool this year. I’m delighted to say that the abstracts from the submitted science are published Open Access in the Journal of Infection Prevention. This first instalment of my report will be “bug-focussed”, followed by another two on different themes:

Part I: Beating the bugs

Part II: Improving the systems

Part III: Thinking outside the box

Opening lectures

The conference kicked off with fellow ‘Reflections’ blogger Prof Andreas Voss. By Andreas’ own admission, he was given a curve-ball of a title: ‘CRE, VRE, C. difficle or MRSA: what should be the priority of infection prevention?’ [No idea where that could have come from…] Andreas developed a framework for grading the priority of our microbial threats, accounting for transmissibility, virulence, antibiotic resistance, at-risk patients, feasibility of decolonisation, cost, and impact of uncontrolled spread. And the result? Any and all microbes that cause HCAI should be a priority of infection prevention. Even those that seem to have less clinical impact (such as VRE) are good indicators of system failure. If we focus too much on one threat, we risk losing sight of the bigger picture.

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What is the fitness cost of mupirocin resistance?

Guest Blogger MRSA , ,

Jon posted a blog last week on mupirocin resistance in MRSA. This week, guest blogger Dr Gwen Knight (bio below) writes about a companion paper also published in the Journal of Antimicrobial Chemotherapy, which models mupirocin resistance…

It is a truth universally acknowledged, that acquiring most mechanisms of drug resistance incurs a fitness cost to the host bacterium. Determining the size of this cost and the impact that this cost will have on the spread of drug resistance is difficult. Is a 10% reduction in growth rate in the laboratory enough to stop resistance spreading in a hospital?

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CRE -> CPE

Jon Otter (@jonotter) CRE , , , ,

CRE CPE 2

I have thought a lot (probably too much) about the best way to describe the issue of carbapenem resistance in Enterobacteriaceae. I decided ages ago that CRE (a la the CDC) is the way to go as a generic term to describe the problem. But the more I think about it, the more I am coming around to the idea that CPE (a la PHE) is better. And here’s why:

  • The real issue from a clinical and infection control viewpoint is CPE. Enterobacteriaceae that are resistant to carbapenems by means other than an acquired carbapenemase (i.e. CRE that are not carbapenemase producers) are important, but they don’t seem to have the same capacity to spread as carbapenemase producers.
  • It’s a really confusing situation in terms of terminology. From the “end user” staff member on the front line and patient, all that really counts is whether it is a CPE or not. It’s really rather confusing to tell a patient that the have a “CRE that is also a carbapenemase producer” – easier just to say “you have a CPE”. (I accept that you will also need to tell a patient if they have a CRE that is not a carbapenemase producer – but I think this way around is easier.)
  • CPE is already en vogue in the UK (mainly due to the PHE Toolkit) so using any other term risks confusion at the time of patient transfer. (Clearly, this point is reversed if you are working in the US!)

I still think that “CRO/CPO” is not the way to go, given the gulf in epidemiology between the Enterobacteriaceae and the non-fermenters (although, sometimes, begrudgingly, you have to go there). What I mean by this is that you will sometimes detect a carbapenemase gene from a PCR but don’t yet know whether it is from a non-fermenter or Enterobacteriaceae species. In this circumstance, this has to go down as a ‘CPO’.

So, there you have it, a personal U-turn. CRE -> CPE. But I wonder whether CDC and PHE and the international community will ever agree a common term…

State of the World’s antibiotics

Andreas Voss (@AVIPNL) Antibiotic resistance ,

Schermafbeelding 2015-09-24 om 20.07.42

The State of the World’s antibiotcs, 2015, was just released by the Center for Diseases Dynamics, Economics & Policy (http://www.cddep.org). For all those interested in antimicrobial resistance this report is a must read.

To cite from the publication, this State of the World’s Antibiotics report records the status of this important global resource and provides critical policy analysis on three issues:

  • global patterns and trends in antibiotic resistance and 
antibiotic use in human beings and animals
  • the existing antibiotic supply and the research and development pipeline
  • interventions that have been shown to help rationalize antibiotic use and are practicable in all countries.

While being wonderful, the reports include a figure from a 2013 Lancet ID publication, a colleague (@ChristinaGrauls) alerted me to. According to figure 2-2: Carbapenem retail sales in selected countries, 2005–2010, the retail sales and thus probable consumption of carbapenems per 1,000 population is identical for the Netherlands and the USA. Somehow, I find that hard to believe.

Mupirocin use drives mupirocin resistance…or does it?

Jon Otter (@jonotter) MRSA , , ,

mupirocin

I’ve blogged before that mupirocin resistance is an inevitable consequence of mupirocin use. Whilst I still think that this is true, my old colleagues from GSTT / KCL have just published an article suggesting that mupirocin resistance in MRSA has more to do with clonal variation than with mupirocin use.

The study is part of an ambitious project to sequence the genome of around 1000 MRSA isolates from across Central and South-East London (Guy’s and St. Thomas’, King’s, and Lewisham). Each isolate was then tested for phenotypic high (HMR) and low (LMR) mupirocin resistance, the genome was scoured for the genetic determinants known to be associated with mupirocin resistance, and clone was derived from the genome sequence. Risk factors for both HMR and LMR were then explored.

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Antibiotics and the Netherlands

Andreas Voss (@AVIPNL) Antibiotic resistance , ,

Schermafbeelding 2015-09-13 om 21.03.43

Antimicrobial resistance, control of antibiotic use and infection control are some of the things the Dutch presumably do well. Some of the Dutch infection control policies, such as “Search & Destroy” helped to stop the introduction of MRSA for a long time. I addition, the prevalence of other MDRO is low in comparison to many other countries. Still, more needed to be done, and consequently, the Dutch were (one of) the first that made antimicrobial stewardship teams (A-teams) compulsory for every hospital and presently plan introduction in other healthcare settings. Last but not least, the fight against antimicrobial resistance will be an important topic, while the Dutch hold the Presidency of the European Union in the first half of 2016.

Thus, what else could we ask for? A few weeks ago, I had at least one request: basic antibiotics.

Due to fading reimbursement policies and the constant pressure to sale drugs for decreasingly lower prices, the production for and/or distribution of several drugs within the Netherlands is no longer possible. Latest victim: i.v. penicillin, which is no longer available in my country (high-resource setting). While it seems difficult to argue for small spectrum antibiotics in the absence of one of the important ones, there is some good news: I no longer have to argue whether to use penicillin or a 3rd generation cephalosporin for certain indications. Ceph it is!

Reconsidering the burden of CRE screening

Jon Otter (@jonotter) CRE , , , , ,

 

swabs

Shortly after the PHE Toolkit was published, I blogged some crude sums to size the burden of CRE admission screening a la Toolkit. I’m pleased to report that colleagues at Imperial have done a much better job of this, published in a letter in the Journal of Infection. The study provides some evidence that the recommendation in the PHE CRE Toolkit to perform pre-emptive isolation of suspected carriers whilst obtaining three negative screens is simply not feasible. The team then compare an alternate strategy – of applying the Tookit triggers to admissions to high risk specialties only (intensive care, nephrology, cardiothoracic surgery, neurosurgery and oncology).

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