Autumn 2014 Update


Autumn NY 2014It’s been another busy quarter on the Micro Blog, with posts on Ebola, coverage of Infection Prevention 2014, and updates on multidrug-resistant Gram-negative rods (especially CRE):

As ever, if you have any questions, fire away. We love the interaction!

Image credit: ‘Autumn in New York’.

Journal Roundup September 2014: Ebola, Environmental science, and MDR-GNR

Ebola CDC global

Another month, another Journal Roundup (free and open acces in Journal of Hospital Infection). This month, Ebola tops the bill as the outbreak continues unabated, it seems inevitable that repatriations of healthcare workers from West Africa will continue and increase. The big journals discuss the appropriate level of PPE, and how to test experimental medicines, amongst other things.

A number of useful environmental science updates feature in the Roundup. For example, an age-old question is whether contaminated hands or surfaces contribute most to transmission. A modeling study found that improvements in hand hygiene compliance are about twice as effective in preventing the transmission of multidrug-resistant organisms compared with improvements in environmental hygiene. So hands are more important right? Well, as the single most important intervention to prevent transmission, then yes.

Several studies on the theme of multidrug resistant Gram-negative rods (MDR-GNR) serve mainly to highlight the limitations in the evidence base for establishing what works to prevent MDR-GNR. One of the major problems here is that ‘MDR-GNR’ is a heterogeneous group comprised of several species and resistance mechanisms, not to mention strain variation. The prevention and control prospects for MDR-GNR are different to pathogens like MRSA, VRE and C. difficile. You need to cover all bases – and there are more bases to cover!

The Reviews and Guidelines section includes a thoughtful piece considering the “hygiene hypothesis” vs. the idea of “biome depletion”, the inadequate level of funding in HCAI research, infection control practice in the ER, the cost of CDI, prospects of phage therapy and interrupting regulatory RNA function.

And finally, a UK study finds pretty high levels of ATP on the beverage trolley. So time to ban the beverage trolley as an infection control risk (along with flowers, pets and child visitors)? Not yet – it’s not that surprising to find ATP (which may originate from food, not microbes) on a beverage trolley. That said, if they’d found a lot of MRSA or, worse, CRE then I’d think twice about a cuppa!

Image credit: CDC Global.

Ebola: PPE and paranoia

The contrast in the stringency of the CDC and UK Department of Health / Health and Safety Executive guidelines for infection prevention and control when dealing Ebola virus disease (EVD) patients is striking. This is particularly acute with regard to recommendations for Personal Protective Equipment (PPE) and terminal disinfection. Having recently reviewed both documents for a webinar on Ebola infection prevention and control (you can download the slides here, by the way), I thought I’d share the contrast:

Table: PPE and disinfection recommendations for dealing with patients with Ebola virus disease. Source: US CDC patient and environmental guidelines, and UK Department of Health. (Please note – this summary chart is designed to be illustrative rather than definitive.)Ebola ppe table

So is there any reason why the level of PPE and type of terminal disinfection required should be any different depending on which side of the Atlantic you happen to be? None whatsoever. So why the discrepancy? It’s difficult to say. This difference in recommendations has prompted the question of “To CDC or not to CDC” in terms of PPE for Ebola, and an opinion piece in Annals of Internal Medicine justifying the CDC approach. It is probably true that the level of PPE recommended by CDC is enough to block transmission, and that the risk of environmental contamination is low enough such that fumigation is not necessary. Probably. But is that good enough when Ebola is on the line? It is certainly true that you can be wearing all the PPE in the world but if you put in on incorrectly, don’t take care of it during use or remove it carelessly you will put yourself at risk.

When I came to decontaminate a room using hydrogen peroxide vapour following a case of Lassa fever in London some years ago, I wore all the PPE that I could lay my hands on (see below)!

Me illustrating the “belt and braces” (aka paranoid) approach to PPE (a la UK, not CDC recommendations).Lassa PPE me_annotated

Did this level of PPE match the risk of exposure to viable Ebola? Perhaps not, but it certainly made me feel a whole lot more secure about entering the room to do the job!

My close shave with viral haemorrhagic fever (VHF)

ebolaAs the outbreak of Ebola continues unabated in Sierra Leone and Liberia (1323 cases and 729 deaths as of July 27), I thought it would be an opportune moment to share a close shave that I had with the closely related Lassa viral haemorrhagic fever (VHF) virus in 2009.

A patient was transferred from Mali to a London hospital with a diagnosis of malaria. The case was initially thought to represent a low risk of VHF (to be fair, Lassa had never been reported in Mali, and the patient came with a diagnosis of malaria). This led to the potential exposure of 123 healthcare workers and visitors, and a busy week for the infection prevention and control team to follow each of these individuals. The useful risk assessment now available from Public Health England may have helped to reduce the number of people exposed.

The patient died in a negative pressure ICU room on the day of admission. At that time, there were no clear recommendations about how to decontaminate the room, so I was involved in developing a decontamination plan with the hospital. Due to the rarity of VHF in the UK, the plan took a week to be authorized by the Health and Safety Executive. This meant that by the time it came to decontaminating the room, the bags of blood-soaked clinical waste, spots of blood on the bed, and used consumables on the floor had been festering for a week. Not ideal.

Our decontamination plan included the use of hydrogen peroxide vapour (HPV) for terminal room disinfection due to the risk that VHF viruses can survive when protected by blood for several weeks on surfaces. This is borne out by some sampling during an outbreak that found intact RNA from the Ebola virus on blood contaminated fomites (although not on fomites that were not contaminated with blood). It’s reassuring that the Department of Health / Health and Safety Executive guidelines published a few years after this case also recommend the use of fumigation for terminal decontamination of hospital rooms.

I ended up being tasked with setting up the HPV equipment that was used to decontaminate the room. We decided it would be better to clean the room after the decontamination to provide some protection to the cleaners. This meant that I was the first person to enter the room after the body of the patient had been removed. I will never forget donning my Tyvek suit, gloves and face-fitted FFP3 mask (see below!). It was exciting: I felt a lot like Dustin Hoffman in Outbreak (the movie that got me interested in medical microbiology in the first place). But it was also frightening. The most frightening part was collecting the bags of clinical waste and consumables from the floor, knowing that they were still likely harbouring live Lassa fever virus. To think that one slip could have infected me with a deadly virus for which there is no treatment…

Lassa PPE me

Figure: Me kitted out in PPE (and looking somewhat apprehensive)

There is legitimate concern that we may see cases of Ebola in the UK and USA in this globalized, interconnected world. If so, then we need to be prepared, and some have questioned our state of readiness. We are fortunate to have comprehensive guidelines from the Department of Health / Health and Safety Executive, including clear guidance on how to decontaminate a room following a case of VHF.

My close shave with VHF has given me a great deal of respect and, frankly, veneration for the brave healthcare workers who are risking their lives on the front line in bringing the current outbreak of Ebola under control.

Photo: Ebola courtesy of Phil Moyer and CDC/Cynthia Goldsmith.